JP7632311B2 - Radial Plate Fixation Screw Tool - Google Patents

Description

The present invention relates to a tool for radial fixation plate fixation screws, which rotates the fixation screws when fixing a radial fixation plate to a radius.

When the radius is fractured, a radius fixation plate is known that spans the fractured portion to immobilize the fractured portion of the radius, instead of a splint (i.e., a splint) or a plaster or FRP cast.

When fixing the radial fixation plate to the radius, multiple fixation screws are screwed into the radius to secure the plate to the radius.

Traditionally, radial fixation plates have been made of metal such as titanium or its alloys, which are strong, lightweight, and highly biosafe.

However, metal plates do not allow X-rays to pass through, meaning that it is not possible to grasp the condition of the fractured area covered by the radius fixation plate.

In recent years, instead of metal plates, plastic radius fixation plates have been developed (see, for example, Patent Document 1). When fixing such plastic radius fixation plates to the radius with screws, if the fixation screws are screwed into the radius too far, the radius fixation plate will crack and break, or the fixation screws will penetrate the radius fixation plate. Therefore, it is necessary to regulate the screw tightening depth and excessive rotation so that the fixation screws are not screwed into the radius too far.

When using metal plates, it was possible to control the torque using a commercially available torque limiter to regulate the depth to which the screws were tightened.

JP 2016-16168 A

However, even when such commercially available torque limiters are used, the following problems remain. For example, in the case of a conventional metal radius fixation plate, if the fixation screw is tightened excessively beyond the required torque, the metal radius fixation plate is able to withstand that torque. However, in the case of a plastic radius fixation plate, if the fixation screw is tightened excessively beyond the required torque, the plastic radius fixation plate cannot withstand that torque and may be damaged or penetrated. Thus, conventional torque limiters were unable to regulate the tightening depth and rotation of the screw.

Therefore, the object of the present invention is to solve the above problems and to provide a tool for fixing screws of a radial fixation plate that can easily and reliably regulate the tightening depth and rotation of the fixing screws of a plastic radial fixation plate.

In order to achieve the above objective, the present invention is configured as follows.

According to a first aspect of the present invention, there is provided a radial fixation plate fixation screw tool for rotating a fixation screw that fixes a radial fixation plate to a radius, the tool comprising:
a rotational force input unit to which a rotational force for rotating the fixing screw is input;
a rotation shaft portion extending in an axial direction from a tip of the rotational force input portion and rotatable relatively to the rotational force input portion;
a center cylinder having a screw coupling portion at a tip end of the rotating shaft portion protruding from the tip end, the center cylinder being disposed outside the rotating shaft portion so as to be movable in the axial direction between a rotating position and an idling position, and the center cylinder having a first engagement projection on an outer circumferential surface;
an outer cylinder that is rotatable integrally with the rotational force input portion and has a second engagement protrusion on its inner circumferential surface, the second engagement protrusion being arranged outside the middle cylinder so as to be relatively movable in the axial direction, and being capable of engaging with the first engagement protrusion and rotatable integrally with the middle cylinder when the middle cylinder is located at the rotation position, and being disengaged from the first engagement protrusion and rotatable relative to the middle cylinder when the middle cylinder is located at the idling position;
A radial fixation plate locking screw tool is provided, comprising:
According to a second aspect of the present invention, there is provided a radial fixation plate fixation screw tool for rotating a fixation screw that fixes a radial fixation plate to a radius, the tool comprising:
a rotational force input unit to which a rotational force for rotating the fixing screw is input;
a rotating shaft portion that extends in an axial direction from a tip of the rotational force input portion, is rotatable integrally with the rotational force input portion, has a screw coupling portion at a tip, and has a first engagement portion on a base end side;
a guide tube that is a separate member from the rotating shaft portion, the guide tube being capable of relatively rotating and relatively moving in the axial direction when the rotating shaft portion is inserted, the guide tube being capable of contacting at its tip end with a guide tube regulating portion of a screw insertion hole of the radial fixation plate or a screw insertion hole of a screw guide block placed on the radial fixation plate, and having at its base end a second engaging portion that engages with the first engaging portion;
In addition to providing
a second rotation stopper portion that can be engaged with a first rotation stopper portion of the screw insertion hole of the screw guide block placed on the radial fixation plate, the second rotation stopper portion being provided on an outer periphery of the guide tube;
A third engagement portion is provided on a base end side of the rotating shaft portion,
a fourth engaging portion that contacts and engages with the third engaging portion at a base end side of the guide tube to restrict movement of the rotation shaft portion in a screw-in direction,
A tool for fixing screws of a radial fixation plate is provided in which the first engagement portion engages with the second engagement portion and the third engagement portion contacts and engages with the fourth engagement portion, thereby restricting the relative rotation between the guide tube and the rotating shaft portion and restricting the movement of the rotating shaft portion in the screwing direction .

According to the first aspect of the present invention, when the first engaging projection and the second engaging projection are engaged, the rotational force generated when the rotational force input unit is rotated is transmitted to the rotating shaft unit through the outer tube and the middle tube, and the fixing screw engaged with the rotating shaft unit is rotated in the tightening direction. On the other hand, when the fixing screw is screwed into the radius and the tightening depth of the fixing screw reaches a dimension to be regulated, the middle tube comes into contact with the radius fixation plate or the guide block arranged on the radius fixation plate, and the middle tube is moved back toward the rotational force input unit relative to the shaft unit, and the engagement around the axis between the first engaging projection and the second engaging projection is released. Then, even if the rotational force input unit is rotated to rotate the outer tube, the outer tube and the middle tube rotate freely, so that the rotational force from the outer tube is not transmitted to the shaft unit, and the rotation is regulated. At the same time, the fixing screw is not screwed in beyond the dimension, and the depth (i.e., the tightening depth of the screw) can also be regulated. Therefore, the tightening depth and rotation of the fixing screw of the resin radius fixation plate can be easily and reliably regulated.
According to the second aspect of the present invention, when the rotational force input part is rotated with respect to the guide tube arranged in the screw insertion hole of the radius fixation plate or the guide block, the rotational shaft part rotates and the first engagement part engages with the second engagement part, so that the rotational shaft part cannot rotate any further and the fixing screw cannot be screwed into the radius together with the rotational shaft part, thereby restricting the depth (i.e., the screw fastening depth) and the rotation. Thus, the fastening depth and rotation of the fixing screw of the resin radius fixation plate can be easily and reliably restricted.

These and other objects and features of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a perspective view showing a state in which a radial fixation plate is fixed to a radius by a fixing screw using a tool for fixing a radial fixation plate to a radius according to a first embodiment of the present invention; A perspective view of a guide block to be placed on a radial fixation plate. A side view of the guide block of FIG. FIG. 1 is a partially perspective explanatory view showing a state in which a fixing screw is inserted through a guide block and a radial fixation plate and fastening is started using a tool for fixing screws of a radial fixation plate according to a first embodiment of the present invention; FIG. 1 is a partially perspective explanatory diagram showing the state where the fixation screw is nearly completed when the fixation screw is inserted through the guide block and the radial fixation plate using a tool for fixing the radial fixation plate screws. FIG. 1 is a partially perspective explanatory diagram showing the state in which the center cylinder is in contact with the guide block and in the idling position when the fixing screw is inserted through the guide block and the radial fixation plate by the radial fixation plate fixing screw tool and tightened. Side view of radial plate locking screw tool FIG. 8 is a vertical cross-sectional view taken along line VIII-VII of FIG. 10 is a cross-sectional view taken along line XI-XI of FIG. A perspective view of a rotating shaft of a tool Side view of the tool barrel A perspective view of the tool's center tube Right side view of the tool's center cylinder A perspective view of the outer cylinder of the tool Longitudinal cross section of the tool's outer cylinder FIG. 13 is a schematic explanatory view, partially in perspective, of a state in which the center cylinder is in contact with the radial fixation plate and is positioned at an idling position to complete fastening when the fastening screw is inserted through the radial fixation plate by the tool for fastening the radial fixation plate screws according to the modified example of the first embodiment of the present invention; FIG. 16B is a perspective view of an example of a radial bone fixation plate for explaining the state of FIG. 16A . FIG. 16B is a partially enlarged perspective view of the FIG. 16B is a vertical cross-sectional view of the vicinity of the screw insertion hole. FIG. 13 is a perspective view of a main body of a tool for fixing a radial bone plate screw according to a second embodiment of the present invention; FIG. 13 is a perspective view of a guide tube of a tool for fixing a radial bone plate screw according to a second embodiment of the present invention; FIG. 19 is a vertical cross-sectional view of the guide tube of FIG. FIG. 19 is a left side view of the guide tube of FIG. FIG. 1 is a perspective view of a state in which the fixation screw is inserted through the guide block and the radial fixation plate by the radial fixation plate fixation screw tool and then tightened; FIG. 1 is a longitudinal sectional view showing a state in which a fixation screw is inserted through a guide block and a radial fixation plate by a radial fixation plate fixation screw tool and tightened; FIG. 1 is a longitudinal cross-sectional view showing a state in which a fixing screw is inserted through a guide block and a radial fixation plate using a radial fixation plate fixing screw tool and then tightened. A longitudinal cross-sectional view showing the state in which the fixation screw is inserted into the radial fixation plate using a radial fixation plate fixation screw tool without a guide block and tightened.

Before continuing with the description of the present invention, reference is made to the accompanying drawings in which like parts are designated by like reference numerals.
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

The tool 1 for fixing a radial fixation plate screw according to the first embodiment of the present invention is a tool for rotating a fixing screw 4 for fixing a radial fixation plate 2 to a radius 3, as shown in Fig. 1. When fixing a radial fixation plate 2 to a radius 3 across a fractured portion 3a of the radius 3, in order to facilitate the screw tightening operation of rotating the fixing screw 4 with the tool 1 for fixing a radial fixation plate 2, a guide block 5 as shown in Figs. 2 and 3 is placed on top of the radial fixation plate 2, and then the screw tightening operation is performed using the screw insertion hole 5d of the guide block 5. After fixing the radial fixation plate 2 to the radius 3, the guide block 5 is removed from the radial fixation plate 2. However, as will be described later in a modified example, the guide block 5 does not have to be used.

As shown in Figure 1, the fractured portion 3a of the radius 3 is divided into the radius body 3b and the fractured fragment 3c by the fractured portion 3a. The radius body 3b and the fractured fragment 3c may be completely separated or may be partially connected.

The radius fixation plate 2 is placed on the radius 3 so that the fractured fragment 3c is fixed in a normally connected state to the radius body 3b.

The radial fixation plate 2 is made of, for example, a thermoplastic resin or a composite material thereof. Examples of thermoplastic resins include PEEK (polyetheretherketone) or polyetherimide.

As an example, the radius fixation plate 2 is a T-shaped plate member made up of a wide distal portion 2a and a proximal portion 2b extending from the distal portion 2a. Here, in this specification, the "proximal portion" refers to the portion of the radius fixation plate 2 that is closer to the heart, and the "distal portion" refers to the portion of the radius fixation plate 2 that is farther from the heart than the proximal portion.

The distal portion 2a is fixed to the fractured portion 3c with a number of screws 4, and the proximal portion 2b is fixed to the radial body 3b with a number of screws 4, so that the radial fixation plate 2 straddles the fractured portion 3a and the fractured portion 3c is normally connected to the radial body 3b.

The distal portion 2a and the proximal portion 2b each have a number of circular screw insertion holes 2d extending in the axial direction in the thickness direction of the radius fixation plate 2 or in a direction in which the tip is inclined outward relative to the thickness direction. If necessary, a fixing screw 4 is inserted into the screw insertion hole 2d, and the fixing screw 4 is screwed into both a part of the screw insertion hole 2d of the radius fixation plate 2 and the radius 3 to fix the radius fixation plate 2 to the radius 3. As shown in Figures 4 to 6, each screw insertion hole 2d is composed of a large-diameter head storage portion 2e and a small-diameter female screw portion 2f that is smaller than the inner diameter of the head storage portion 2e.

As shown in Figures 4 to 6, the fixing screw 4 inserted into the screw insertion hole 2d is made of hard metal and is composed of a head 4c and a shaft 4a connected to the head 4c.

The shaft portion 4a has a diameter smaller than the inner diameter of the female threaded portion 2f of the screw insertion hole 2d, and is capable of penetrating the female threaded portion 2f. The shaft portion 4a is formed with a main thread 4b that self-taps into the radius 3 after penetrating the screw insertion hole 2d.

As an example, the head 4c has an outer diameter that is the same as the inner diameter of the female threaded portion 2f, and is stored in the head storage portion 2e when the screw is tightened. A sub-thread 4d is formed on the outer peripheral surface of the shaft side of the head 4c, which is screwed into the female threaded portion 2f of the screw insertion hole 2d. Note that instead of a configuration in which the sub-thread 4d is screwed into the female threaded portion 2f, the female threaded portion 2f may be used as a threaded portion without a female thread being formed in advance, and the sub-thread 4d may be used to screw into the threaded portion by performing a self-tapping action.

A hexalobular hole 4j is formed on the top surface of the head 4c, and the screw coupling portion 12c of the rotating shaft portion 12 of the tool 1 described later is coupled thereto, allowing the fixing screw 4 to rotate forward and backward. The hexalobular hole 4j is an example, but the hexalobular hole 4j and the screw coupling portion 12c in the shape of a hexalobular wrench are in contact with each other at the crest and the valley, and are preferable because they do not slip unless both are completely smoothed. In other words, the hexalobular hole 4j has the effect of efficiently transmitting the tightening torque and reducing the risk of damage to the tool or the screw head by eliminating stress concentration.

As shown in Figures 4 to 6, the guide block 5 is placed on top of the radial fixation plate 2 to facilitate the screw tightening operation when rotating the fixation screw 4 with the radial fixation plate fixation screw tool 1.

2 and 3, as an example, the outer shape of the guide block 5 is the same as that of the radius fixation plate 2, so that it covers the entire radius fixation plate 2 and is easy to stack. Specifically, the guide block 5 has a wide distal portion 5a with the same shape as the wide distal portion 2a of the radius fixation plate 2, and a proximal portion 5b extending from the distal portion 5a and with the same shape as the proximal portion 2b of the radius fixation plate 2, forming a T-shaped member. The guide block 5 makes it easier to guide the fixation screw 4 than in a state without the guide block.

3, the outer periphery of the back surface of the guide block 5 has a retaining claw 5c that can be engaged and held on the outer periphery of the radius fixation plate 2. Holding with the retaining claw 5c is just one example, and the guide block 5 may be fixed to the radius fixation plate 2 by a fixing method other than the retaining claw 5c, such as a dedicated screw or a dual-purpose screw.

In the distal portion 5a and the proximal portion 5b, a number of circular screw insertion holes 5d are formed, each extending in the thickness direction of the guide block 5 or in the direction in which the tip is inclined outward relative to the thickness direction, in other words, in the thickness direction of the radius fixation plate 2 or in the direction in which the tip is inclined relative to the thickness direction. Each screw insertion hole 5d is formed and arranged to correspond to each screw insertion hole 2d.

As shown in Figure 4, each screw insertion hole 5d is composed of a large-diameter center tube guide portion 5e and a small-diameter rotating shaft portion through-hole 5f that is smaller than the inner diameter of the center tube guide portion 5e. A center tube regulating portion 5h composed of an annular edge is formed at the boundary between the center tube guide portion 5e and the rotating shaft portion through-hole 5f. The tip of a center tube 13 of a tool 1 described later comes into contact with the center tube regulating portion 5h, regulating the position of the center tube 13 so that it does not enter the rotating shaft portion through-hole 5f in each screw insertion hole 5d beyond the center tube regulating portion 5h.

As shown in Figs. 4 to 15, the tool 1 for fixing a radial fixation plate screw includes at least a rotational force input section 11, a rotating shaft section 12, a middle cylinder 13, and an outer cylinder 14. For example, the tool 1 may be made entirely of metal, or the middle cylinder 13 and the outer cylinder 14 may be made of synthetic resin and the remaining parts may be made of metal. The tool 1 for fixing a radial fixation plate screw may further include a biasing member 15. Figs. 4 to 6 are diagrams showing an outline of the tool 1, and Figs. 7 to 15 are diagrams showing the specific configuration of the tool 1, but the functions of both are almost the same. In particular, the major difference is that the shapes of the first engagement protrusion 13c and the second engagement protrusion 14c are simplified and illustrated as gear shapes rather than plate shapes with trapezoidal cross sections as described later, but the functions are the same.

The rotational force input unit (rotational force input member) 11 is a part that applies a rotational force around the axis to the tool 1, and is composed of a rod-shaped member. As an example, the rotational force input unit 11 may be connected to a surgical tool, and the rotational force from the surgical tool may be input to the rotational force input unit 11 to enable the tool 1 to rotate forward and backward around the axis. Or, as another example, when rotating by hand, the tool 1 can be rotated forward and backward around the axis by having a flat surface portion 11a extending in the axial direction and pinching the flat surface portion 11a and the curved back surface portion of the flat surface portion 11a with the fingers. The flat surface portion 11a is not necessarily required since the rotational force input unit 11 only needs to rotate forward and backward around the axis to tighten and loosen the fixing screw 4. The tip of the rotational force input unit 11 has a cylindrical fitting recess 11b.

As shown in Figures 7 to 10, the rotating shaft portion (rotating shaft member) 12 is arranged coaxially with the rotational force input portion 11 and comprises a shaft portion main body 12a having a hexagonal cross section, a tapered screw connection portion 12c at the tip of the shaft portion main body 12a, a cylindrical fitting protrusion 12d arranged at the base end of the shaft portion main body 12a, and an annular spring locking protrusion 12e located near the base end of the shaft portion main body 12a and protruding radially beyond the outer diameter of the shaft portion main body 12a.

The fitting protrusion 12d is fitted and connected into the cylindrical fitting recess 11b at the tip of the rotational force input unit 11 so as to be relatively rotatable around the axis. Therefore, the shaft body 12a extends in the axial direction from the tip of the rotational force input unit 11 via the fitting protrusion 12d and is rotatable relative to the rotational force input unit 11. The method of connecting the rotating shaft unit 12 and the rotational force input unit 11 may be such that the relationship between the protrusion and the recess is reversed.

The screw coupling portion 12c is a hexalobular screw rotation portion that is disposed at the tip of the shaft body 12a and can be coupled to the hexalobular hole 4j of the head 4c of the fixing screw 4 so as not to rotate relative to the hexalobular screw, and allows the fixing screw 4 to rotate forward and backward in order to tighten or loosen the fixing screw 4. The screw coupling portion 12c is configured as a hexalobular screw rotation portion in the shape of a hexalobular wrench that can engage with the hexalobular hole 4j of the head 4c when the hexalobular screw 4 is used as the fixing screw 4.

The middle tube 13 is made of a cylindrical member, as shown in Figures 7 to 9 and Figures 11 to 13.

The middle tube 13 comprises a middle tube main body 13a and a first engagement protrusion 13c protruding radially from the outer peripheral surface of the base end of the middle tube main body 13a.

The middle tube body 13a is arranged on the outer peripheral surface of the base end side of the hexagonal cross-sectional shaft body 12a of the rotating shaft portion 12, and has a hexagonal cross-sectional through hole 13b which is an example of a part that cannot rotate around the axis relative to the hexagonal cross-sectional shaft body 12a (in other words, can rotate integrally with the hexagonal cross-sectional shaft body 12a) and can move in the axial direction between a rotation position A and an idling position B.

The screw connection portion 12c at the tip of the rotating shaft portion 12 always protrudes from the tip of the middle tube body 13a.

Near the base end of the shaft body 12a, a coil spring 15 as an example of a biasing member 15 is arranged in a slightly compressed state between the annular base end surface 13d of the middle tube body 13a and the annular spring locking protrusion 12e, and the spring force of the coil spring 15 constantly biases the middle tube body 13a toward the tip side relative to the shaft body 12a, so that the middle tube body 13a is always located at the rotation position A rather than the idling position B. However, the coil spring 15 is not necessarily required. For example, in a tool 1 with a simple configuration, the coil spring 15 can be omitted, and the middle tube 13 can be returned to the initial position, the rotation position A, by hand every time the fixing screw 4 is tightened, and the middle tube 13 can be used while being careful not to move the middle tube 13 when tightening the fixing screw. Even in such a case, the above-mentioned idling operation can be performed at the idling position B.

As an example, the first engagement protrusion 13c is formed in a plate shape with one or more in the circumferential direction and a trapezoidal cross section curved in the radial direction. For example, four first engagement protrusions 13c are formed at a predetermined interval, for example, at 90 degree intervals, and the space on the outer circumferential surface between adjacent first engagement protrusions 13c functions as a first engagement recess 13e into which a second engagement protrusion 14c described later enters in the axial direction so as to be removable. The tip side of each first engagement protrusion 13c has an inclined surface 13g that is inclined so as to approach the radial center as it approaches the tip in the axial direction, allowing smooth engagement and disengagement with the second engagement protrusion 14c described later.

The outer tube 14 is composed of a cylindrical member having a tapered shape and a larger diameter than the inner tube 13.

The outer tube 14 is arranged outside the middle tube 13 so as to be relatively movable in the axial direction, and is provided with an outer tube body 14a having a circular through hole 14b, and a second engagement protrusion 14c formed on the inner peripheral surface of the middle part of the outer tube body 14a so as to protrude toward the radial center and engageable with the first engagement protrusion 13c.

The through hole 14b has a large inner diameter at the base end and gradually becomes smaller in diameter toward the tip, so that the middle tube 13 cannot come off the outer tube 14 in the axial direction toward the tip.

The outer cylinder 14 is arranged so that the tip end portion of the middle cylinder 13 is exposed from the tip of the outer cylinder 14, and covers the base end portion of the middle cylinder 13, the base end portion of the rotating shaft portion 12, and the tip end portion of the rotational force input portion 11. Furthermore, a fixing pin 16 is inserted diametrically into the tip end portion of the rotational force input portion 11 and the base end portion of the outer cylinder 14 to fix the tip end portion of the rotational force input portion 11 and the base end portion of the outer cylinder 14. Therefore, the rotational force input portion 11 and the outer cylinder 14 are configured to rotate forward and backward as a unit.

As an example, the second engagement protrusion 14c of the outer tube 14 is formed in one or more circumferential directions, and is a plate-like shape with a trapezoidal cross section curved in the radial direction. For example, the second engagement protrusion 14c is formed in four pieces at predetermined intervals, for example, at 90 degree intervals, and the space on the outer circumferential surface between adjacent second engagement protrusions 14c functions as a second engagement recess 14e into which the first engagement protrusion 13c enters in the axial direction so as to be removable.

Therefore, the first engagement protrusion 13c can move axially forward and backward relative to the second engagement recess 14e between rotation position A and idling position B. At rotation position A, the first engagement protrusion 13c enters the second engagement recess 14e, and the first engagement protrusion 13c and the second engagement protrusion 14c engage around the axis, making them unable to rotate relative to each other around the axis. At idling position B, the first engagement protrusion 13c is pulled out of the second engagement recess 14e, and the engagement between the first engagement protrusion 13c and the second engagement protrusion 14c around the axis is released, making them able to rotate relative to each other around the axis.

At the same time, within the first engagement recess 13e, the second engagement protrusion 14c can advance and retreat in the axial direction between rotation position A and idling position B. At rotation position A, the second engagement protrusion 14c enters the first engagement recess 13e, and the first engagement protrusion 13c and the second engagement protrusion 14c are engaged around the axis, making them unable to rotate relative to each other around the axis. At idling position B, the second engagement protrusion 14c is pulled out of the first engagement recess 13e, and the engagement between the first engagement protrusion 13c and the second engagement protrusion 14c around the axis is released, making them able to rotate relative to each other around the axis.

The base end of each second engagement protrusion 14c has an inclined surface 14g that is inclined so as to approach the radial center as it approaches the tip in the axial direction, and the inclined surface 14g is slidable against the inclined surface 13g of the first engagement protrusion 13c, allowing smooth engagement and disengagement with the first engagement protrusion 13c around the axis.

The coil spring 15 is positioned near the base end of the rotating shaft portion 12 with a gap between it and the rotating shaft portion 12 so as not to interfere with the forward and reverse rotation of the rotating shaft portion 12, and constantly biases the middle tube 13 toward the tip side along the axial direction so that the middle tube 13 is located at rotation position A.

Tool 1 having such a configuration can be used as follows.

First, the guide block 5 is placed on the radius fixation plate 2 and held in place using a fixing method such as the retaining claws 5c, a dedicated screw, or a dual-purpose screw. Then, as shown in Figure 4, the guide block 5 and the radius fixation plate 2 are placed together on the radius 3 so that the radius fixation plate 2 straddles the fractured portion 3a of the radius 3.

4, a fixing screw 4 is inserted into one screw insertion hole 5d of the guide block 5 and into the screw insertion hole 2d of the radius fixation plate 2, and the screw coupling portion 12c of the rotating shaft portion 12 of the tool 1 is coupled into the hexalobular hole 4j of the head 4c of the fixing screw 4. In this state, the screw insertion hole 2d, the screw insertion hole 5d, the fixing screw 4, and the tool 1 are held coaxially with each other.

Next, the rotational force input unit 11 of the tool 1 is started to rotate in the direction of tightening the fixing screw 4. As a result, the rotational force from the rotational force input unit 11 is transmitted to the outer tube 14, the middle tube 13 biased to the rotational position A by the coil spring 15, the rotational shaft 12, and the fixing screw 4, and the fixing screw 4 is screwed into the radius 3 while being guided by the screw insertion hole 5d of the guide block 5. That is, since the middle tube 13 is located at the rotational position A, the rotational force from the outer tube 14 is reliably transmitted to the middle tube 13 by the engagement around the axis between the first engagement protrusion 13c and the second engagement protrusion 14c. At this time, the screw insertion hole 5d of the guide block 5 guides the fixing screw 4 so that it advances smoothly in its axial direction, and the shaft 4a of the fixing screw 4 begins to be screwed into the radius 3. When the fixing screw 4 is screwed in, the main thread 4b of the shaft 4a of the fixing screw 4 performs a self-tapping action on the radius 3 and is screwed in.

5, as the fixing screw 4 continues to rotate in the tightening direction and is screwed into the radius 3, the center tube 13 advances in the center tube guide portion 5e of the screw insertion hole 5d, and the center tube 13 comes into contact with the center tube regulating portion 5h. As the fixing screw 4 continues to rotate in the tightening direction even after the contact, it is further screwed into the radius 3 and advances in the axial direction, and the center tube 13 begins to retreat relative to the rotating shaft portion 12. This means that the center tube 13 begins to move from the rotation position A toward the idling position B. At this time, as an example, the auxiliary thread 4d of the head 4c of the fixing screw 4 is screwed into the female thread portion 2f of the screw insertion hole 2d of the radius fixation plate 2 or performs a self-tapping action, and the radius fixation plate 2 is fixed in close contact with the radius 3.

As a result, as shown in FIG. 6, the fixing screw 4 is positioned at a predetermined position (i.e., the fixing screw tightening position) relative to the radial fixation plate 2. Here, the predetermined position is, for example, a position where the head 4c of the fixing screw 4 contacts the countersunk surface of the screw insertion hole 2d of the radial fixation plate 2 (i.e., the boundary between the head storage section 2e and the female thread section 2f). At this time, the lower end of the head 4c of the fixing screw 4 is positioned at a certain distance (for example, 2 mm) from the countersunk surface of the screw insertion hole 2d. However, this is only one example, and the predetermined position may be a position shifted toward the opening side of the head storage section 2e from the countersunk surface, or conversely, a position that is inserted into the female thread section 2f side from the countersunk surface. When the fixing screw 4 is positioned at such a predetermined position, if the tool 1 moves the middle cylinder 13 from the rotation position A to the idling position B, the engagement between the first engagement protrusion 13c and the second engagement protrusion 14c around the axis is released. Then, the outer cylinder 14 rotates idly relative to the middle cylinder 13, and it becomes impossible to transmit any more rotational force from the tool 1 to the fixing screw 4, and the screw tightening operation becomes impossible. As a result, the fixing screw 4 is maintained in a predetermined position relative to the radius fixation plate 2, and the depth and rotation of the fixing screw 4 are restricted. Note that the certain distance is determined by the thickness of the radius fixation plate 2 or the thickness of the head 4c of the fixing screw 4, and varies, so it is difficult to uniformly prescribe the certain distance, and so it is illustrated as an example.

When releasing the tightening, the fixing screw 4 can be loosened and removed by rotating the rotating shaft portion 12 in the reverse direction using the tool 1 or a general screwdriver without the guide block.

According to the first embodiment, at the rotation position A of the middle cylinder 13, the first engagement protrusion 13c and the second engagement protrusion 14c are engaged, and the rotational force generated when the rotational force input unit 11 is rotated is transmitted to the rotating shaft unit 12 via the outer cylinder 14 and the middle cylinder 13, and the fixing screw 4 connected to the rotating shaft unit 12 is rotated in the tightening direction. On the other hand, when the fixing screw 4 is screwed into the radius 3 by a predetermined distance, the middle cylinder 13 comes into contact with the guide block 5 arranged on top of the radius fixing plate 2, and the middle cylinder 13 is moved back toward the rotational force input unit 11 side relative to the rotating shaft unit 12. This means that the middle cylinder 13 moves axially from the rotation position A to the idling position B, and the engagement around the axis between the first engagement protrusion 13c and the second engagement protrusion 14c is released. Then, even if the outer tube 14 is rotated by rotating the rotational force input portion 11, the outer tube 14 and the middle tube 13 rotate idly, and the rotational force from the outer tube 14 is not transmitted to the rotating shaft portion 12, so that the rotation is restricted, and the fixing screw 4 is not screwed in beyond the predetermined dimension, so that the depth can also be restricted. Therefore, the tightening depth and rotation restriction of the fixing screw 4 of the resin radius fixation plate 2 can be easily and reliably implemented. In other words, by moving the middle tube 13 from the rotation position A to the idling position B to disengage, the depth restriction and rotation restriction can be implemented, and excessive tightening force is prevented from being applied to the fixing screw 4 and the radius fixation plate 2 any more.

The present invention is not limited to the first embodiment, and can be embodied in various other ways. For example, as shown in Figs. 16A to 16D, when the guide block 5 is not used, the radial fixation plate 2 may be provided with a middle tube regulating portion 2h as an edge portion as a position regulating portion for the middle tube 13 to move from the rotation position A to the free rotation position B by contacting the middle tube 13. That is, the screw insertion hole 2d of the radial fixation plate 2 is not constituted by the head storage portion 2e and the female thread portion 2f, but a middle tube guide portion 2j corresponding to the middle tube guide portion 5e and a rotating shaft portion penetrating portion 2k corresponding to the rotating shaft portion penetrating portion 5f, which have an inner diameter larger than that of the head storage portion 2e, are formed in the portion closer to the opening side of the screw insertion hole 2d than the head storage portion 2e, and the middle tube regulating portion 2h corresponding to the middle tube regulating portion 5h is provided at the boundary portion between the two. As a result, as the rotation of the fixing screw 4 in the tightening direction progresses and the fixing screw 4 is screwed into the radius 3, the center cylinder 13 advances within the center cylinder guide portion 2j of the screw insertion hole 2d, and the center cylinder 13 comes into contact with the center cylinder regulating portion 2h. As the rotation in the tightening direction continues even after the contact, the fixing screw 4 is further screwed into the radius 3 and advances in the axial direction, and the center cylinder 13 begins to retreat relative to the rotating shaft portion 12. This means that the center cylinder 13 begins to move from the rotation position A toward the idling position B. The subsequent operations are the same as those in the first embodiment.

According to this modified example, depth position regulation and rotation regulation can be performed by the tool 1 without using a guide block 5.

The radial fixation plate fixation screw tool 71 according to the second embodiment of the present invention is a tool that can be used in the same manner as the radial fixation plate fixation screw tool 1 shown in Figure 1.

Each screw insertion hole 5d of the radius fixation plate 2 is provided with a rotation stop notch 5g cut radially at a predetermined circumferential position, for example, at 120 degree intervals around the axis, as an example of a first rotation stopper. Rotation stop protrusions 8g protruding radially at 120 degree intervals, for example, on the outer peripheral surface of the guide tube 8 of the tool 71 as an example of a second rotation stopper, which will be described later, fit into and engage with the rotation stop notch 5g, thereby restricting the rotation of the rotating shaft portion 12 and preventing it from rotating.

As shown in Figure 21 etc., similar to the first embodiment, the fixing screw 4 inserted into the screw insertion hole 2d is made of hard metal and is composed of a head 4c and a shaft 4a connected to the head 4c.

As shown in Figures 2 to 3 and 21, the inner tube guide portion 5e of each screw insertion hole 5d can be read as the guide tube guide portion 5e. Therefore, each screw insertion hole 5d is composed of a large-diameter guide tube guide portion 5e and a small-diameter rotary shaft portion through-hole 5f that is smaller than the inner diameter of the guide tube guide portion 5e. A guide tube restricting portion 5h composed of an annular edge is formed at the boundary between the guide tube guide portion 5e and the rotary shaft portion through-hole 5f. The tip of the guide tube 8 of the tool 71 described later comes into contact with the guide tube restricting portion 5h, restricting the position of the guide tube 8 so that it does not enter the rotary shaft portion through-hole 5f in each screw insertion hole 5d beyond the guide tube restricting portion 5h.

As shown in Figures 17 to 20, the tool 71 for fixing the radial fixation plate screws is composed of a main body 7 and a guide tube 8 which is a separate member from the main body 7. As an example, the main body 7 and the guide tube 8 can be made of a metal such as stainless steel.

The main body 7 has a rotational force input portion (rotational force input member) 81 and a rotating shaft portion (rotating shaft member) 82.

The rotational force input unit 81 is a part that applies a rotational force around the axis to the tool 71, and is composed of a rod-shaped member. As an example, the rotational force input unit 81 may be connected to a surgical tool, and the rotational force from the surgical tool may be input to the rotational force input unit 81 to enable the tool 71 to rotate forward and backward around the axis. Or, as another example, when rotating by hand, the tool 71 may have a flat surface portion 81a extending in the axial direction, and may be rotated forward and backward around the axis by pinching the flat surface portion 81a and the curved back surface portion of the flat surface portion 81a with the fingers. The flat surface portion 81a is not necessarily required for the rotational force input unit 81, as long as it is possible to rotate forward and backward around the axis to tighten and loosen the fixing screw 4.

The rotating shaft 82 is arranged coaxially with the rotational force input section 81 and includes a shaft body 82a having a circular cross section, a tapered screw coupling section 82c at the tip of the shaft body 82a, and a first engagement section arranged on the base end side of the shaft body 82a, i.e., at or near the base end. The shaft body 82a may be integrally formed with the rotational force input section 81 as a single member, or may be formed as a separate member from the rotational force input section 81 and connected to it.

The screw coupling portion 82c is a hexalobular screw rotation portion that is disposed at the tip of the shaft body 82a and can be non-rotatably coupled to the hexalobular hole 4j of the head 4c of the fixing screw 4, and allows the fixing screw 4 to rotate forward and backward in order to tighten or loosen the fixing screw 4. When a hexalobular screw is used as the fixing screw 4, the screw coupling portion 82c is configured as a hexalobular screw rotation portion in the shape of a hexalobular wrench that can engage with the hexalobular hole 4j of the head 4c.

The base end of the shaft body 82a is configured with a ring-shaped protrusion 82k that protrudes in the radial direction. This ring-shaped protrusion 82k functions as an example of a third engagement portion, which will be described later.

A first engagement portion 82j is formed adjacent to the annular protrusion 82k at the tip side of the shaft body 82a. The first engagement portion 82j is, as an example, configured with a male thread. The male thread of the first engagement portion 82j is formed to be radially smaller than the outer diameter of the annular protrusion of the annular protrusion 82k.

As shown in Figures 18 to 20, the guide tube 8 is composed of a cylindrical member into which the rotating shaft portion 82 is inserted so that it can move relatively in the axial direction and rotate relatively around the axis.

The guide tube 8 comprises a guide tube main body 8m and an annular projection 8n that projects radially from the outer peripheral surface of the base end of the guide tube main body 8m and has a base end face 8k as an example of a fourth engagement portion. The inner diameters of the guide tube main body 8m and the annular projection 8n are the same, allowing the rotating shaft 82a to be inserted so that it can smoothly advance and retreat in the axial direction and rotate forward and backward around the axis. As described below, the base end face 8k contacts an annular projection 82k, allowing the rotating shaft 82 to be restricted from moving in the axial direction toward the tip side relative to the guide tube 8.

The length of the guide tube 8 can be determined taking into consideration the length of the screw insertion hole 2d in the radius fixation plate 2 and the length of the rotation shaft portion through-hole 5f of the screw insertion hole 5d in the guide block 5 so that when the guide block 5 is placed on the radius fixation plate 2 and the fixation screw 4 is screwed into the radius 3, the screw-in depth (i.e., depth) of the fixation screw 4 screwed into the radius 3 will be a predetermined dimension.

On the inner circumferential surface of the annular protrusion 8n, a female thread into which the male thread of the first engagement portion 82j is screwed is formed as an example of the second engagement portion 8j. When the male thread of the first engagement portion 82j is completely screwed into the female thread of the second engagement portion 8j, the annular protrusion 82k contacts the base end face 8k, and the first engagement portion 82j cannot be screwed further into the second engagement portion 8j. As a result, the contact between the annular protrusion 82k and the base end face 8k restricts the depth and rotation of the fixing screw 4.

In addition, the thread pitch of the female thread of the second engagement portion 8j and the male thread of the first engagement portion 82j can be the same as the thread pitch of the secondary thread 4d of the head 4c of the fixing screw 4.

The reason for keeping the pitch the same is to avoid the following problems:

First, when the thread pitch of the female thread of the second engagement portion 8j and the male thread of the first engagement portion 82j is larger than the thread pitch of the secondary thread 4d of the head portion 4c, a load equivalent to the pitch difference is applied between the guide tube 8 and the guide block 5, or between the tip of the screw connection portion 82c of the rotating shaft portion 82 and the fixing screw 4, or between the fixing screw 4 and the female thread portion 2f of the radius fixation plate 2, which may result in premature wear or damage to each component or damage to the female thread portion 2f of the radius fixation plate 2.

Furthermore, when the thread pitch of the female thread of the second engagement portion 8j and the male thread of the first engagement portion 82j is larger than the thread pitch of the secondary thread 4d of the head portion 4c, a gap begins to form between the tip of the screw coupling portion 82c of the rotating shaft portion 82 and the fixing screw 4. In other words, this means that the tip of the screw coupling portion 82c of the rotating shaft portion 82 is not properly engaged with the fixing screw 4. This causes the tip of the screw coupling portion 82c of the rotating shaft portion 82 to become "stripped."

If it is necessary to prevent these problems from occurring, the pitch can be made the same as described above.

On the outer peripheral surface of the guide tube body 8m of the guide tube 8, rotation stopper protrusions 8g are formed at predetermined circumferential positions, for example, at intervals of 120 degrees around the axis, so as to protrude radially and extend along the axial direction in order to stop rotation in the radial direction. Therefore, when a part of the lower side of the guide tube 8 is inserted into the guide tube guide portion 5e of one screw insertion hole 5d of the guide block 5, the three rotation stopper protrusions 8g of the guide tube 8 are fitted into the three rotation stopper notches 5g of the male screw insertion hole 5d to lock it around the axis, thereby stopping the rotation of the guide tube 8 relative to the screw insertion hole 5d. In this way, the first rotation stopper and the second rotation stopper are locked and locked at intervals of 120 degrees, in other words evenly around the axis, so that the rotation around the axis can be restricted smoothly and reliably compared to the case where the rotation stopper parts are arranged unevenly.

A tool 71 having such a configuration can be used as follows.

First, the guide block 5 is placed on the radius fixation plate 2 and held in place using a fixing method such as the retaining claws 5c, dedicated screws, or dual-purpose screws. Then, as shown in Figure 21, the guide block 5 and the radius fixation plate 2 are placed together on the radius 3 so that the radius fixation plate 2 straddles the fractured portion 3a of the radius 3.

Next, insert a part of the lower side of the guide tube 8 into the guide tube guide portion 5e of one of the screw insertion holes 5d of the guide block 5, bring the tip of the guide tube 13 into contact with the guide tube restriction portion 5h, and fit the rotation stop protrusion 8g of the guide tube 8 into the rotation stop notch 5g of the male screw insertion hole 5d to stop the guide tube 8 from rotating relative to the screw insertion hole 5d. In this state, insert the fixing screw 4 into the guide tube 8.

Next, the rotating shaft 82 of the main body 7 is inserted into the guide tube 8, and the screw coupling portion 82c of the rotating shaft 82 of the tool 71 is coupled into the hexalobular hole 4j of the head 4c of the fixing screw 4. In this state, the screw insertion hole 2d, the screw insertion hole 5d, the fixing screw 4, and the tool 71 are held coaxially with each other.

Next, the rotational force input portion 81 of the tool 71 is started to rotate in the direction of tightening the fixing screw 4. As a result, the rotational force from the rotational force input portion 81 is transmitted to the rotating shaft portion 82 and the fixing screw 4, and the fixing screw 4 is screwed into the radius 3 while being guided by the screw insertion hole 5d of the guide block 5. At this time, the shaft portion 4a of the fixing screw 4 begins to be screwed into the radius 3 while the screw insertion hole 5d of the guide block 5 guides the fixing screw 4 so that it advances smoothly in its axial direction. When the fixing screw 4 is screwed in, the main thread 4b of the shaft portion 4a of the fixing screw 4 performs a self-tapping action on the radius 3 and is screwed in. When the fixing screw 4 is screwed into the radius 3 to a certain extent, the male thread of the first engagement portion 82j of the rotating shaft portion 82 begins to be screwed into the female thread of the second engagement portion 8j. At this time, as an example, the auxiliary thread 4d of the head 4c of the fixing screw 4 is screwed into the female thread portion 2f of the screw insertion hole 2d of the radius fixing plate 2, so that the radius fixing plate 2 is fixed in close contact with the radius 3.

22, the fixing screw 4 is located at a predetermined position (so to speak, the fixing screw tightening position) with respect to the radial fixation plate 2. Here, the predetermined position is, for example, a position where the head 4c of the fixing screw 4 contacts the countersunk surface of the screw insertion hole 2d of the radial fixation plate 2 (i.e., the boundary between the head storage section 2e and the female thread section 2f). At this time, the lower end of the head 4c of the fixing screw 4 is located at a position up to a certain distance (for example, 2 mm) from the countersunk surface of the screw insertion hole 2d. However, this is only one example, and the predetermined position may be a position shifted toward the opening side of the head storage section 2e from the countersunk surface, or conversely, a position that is inserted into the female thread section 2f side from the countersunk surface. When the fixing screw 4 is located at such a predetermined position, the annular protrusion 82k contacts the base end surface 8k with the tool 71, and the first engagement section 82j cannot be screwed further into the second engagement section 8j. As a result, due to contact between the annular protrusion 82k and the base end face 8k, it becomes impossible to transmit any more rotational force from the tool 71 to the fixation screw 4, and the screw tightening operation cannot be performed. This maintains the fixation screw 4 in a predetermined position relative to the radius fixation plate 2, and restricts the depth and rotation of the fixation screw 4. Note that the certain distance is determined by the thickness of the radius fixation plate 2 or the thickness of the head 4c of the fixation screw 4, and varies, so it is difficult to uniformly prescribe the certain distance, and is therefore illustrated as an example.

When releasing the tightening, the fixing screw 4 can be loosened and removed by rotating the rotating shaft portion 82 in the reverse direction using the tool 71 or a general screwdriver without the guide block.

According to the second embodiment, the rotational force input unit 81 is rotated to rotate the rotating shaft unit 82 relative to the guide tube 8 inserted into the screw insertion hole 5d of the radius fixation plate 2 or the guide block 5, and the fixing screw 4 is started to be screwed into the radius 3. After that, when the fixing screw 4 is screwed into the radius 3 and the fastening depth of the fixing screw 4 reaches a predetermined dimension, the annular protrusion 82k and the base end surface 8k come into contact and engage. At this time, the rotating shaft unit 82 cannot rotate any further, and the fixing screw 4 cannot be screwed into the radius 3 together with the rotating shaft unit 82, and the depth can be restricted. At the same time, the male thread of the first engagement unit 82j and the female thread of the second engagement unit 8j are screwed into each other, and the annular protrusion 82k and the base end surface 8k come into contact and engage with each other, preventing the rotating shaft unit 82 from rotating, thereby preventing overrotation and restricting rotation.

The present invention is not limited to the second embodiment, and can be embodied in various other ways. For example, as shown in FIG. 23, when the guide block 5 is not used, a rotation stop notch 2g similar to the rotation stop notch 5g is formed in the male screw insertion hole 2d as shown in FIG. 1. That is, in each screw insertion hole 2d of the radius fixation plate 2, a rotation stop notch 2g cut radially at a predetermined position in the circumferential direction, for example, at intervals of 120 degrees around the axis, is arranged as an example of a third rotation stopper. As with the rotation stop notch 5g, the rotation stopper protrusions 8g protruding radially at intervals of 120 degrees from the outer circumferential surface of the guide tube 8 of the tool 71 as an example of a second rotation stopper enter and engage with the rotation stopper protrusions 8g, which are an example of a second rotation stopper, and restrict the rotation of the rotating shaft portion 82 so that it does not rotate, thereby preventing the rotation from being stopped. At this time, the inner diameter of the screw insertion hole 2d is made larger than the outer diameter of the guide tube main body 8m so that at least a part of the screw insertion hole 2d enters the guide tube main body 8m.

Therefore, while holding the guide tube 8 with one hand along the axial direction of the screw insertion hole 2d of the radius fixation plate 2, the guide tube 8 is inserted into the screw insertion hole 2d, and the rotation stop protrusion 8g enters and engages the rotation stop notch 2g, restricting the rotation shaft portion 82 from rotating and preventing rotation. Next, with the other hand, the fixing screw 4 is inserted into the guide tube 8 and the rotating shaft portion 82 is inserted, and the rotating shaft portion 82 is rotated in the same manner as in the second embodiment, screwing in the fixing screw 4 and screwing the first engagement portion 82j into the second engagement portion 8j.

Thereafter, when the tightening depth of the fixing screw 4 reaches a predetermined dimension, the first engagement portion 82j can no longer be screwed into the second engagement portion 8j, and the annular protrusion portion 82k comes into contact with and engages with the base end face 8k, preventing the rotating shaft portion 82 from rotating and advancing any further. As a result, the fixing screw 4 together with the rotating shaft portion 82 cannot be screwed into the radius 3, and rotation and depth restrictions can be performed.

According to this modified example, depth position regulation and rotation regulation can be performed by the tool 71 without using the guide block 5.

In addition, by appropriately combining any of the various embodiments or modifications described above, it is possible to achieve the effects of each of them. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features of different embodiments or examples are also possible.
Although the present invention has been fully described in connection with the preferred embodiment with reference to the accompanying drawings, various changes and modifications will become apparent to those skilled in the art, and such changes and modifications are to be understood as being included within the scope of the present invention as defined by the appended claims, unless they depart therefrom.

The tool for fixing screws of a radial fixation plate according to the above aspect of the present invention can easily and reliably regulate the tightening depth and rotation of the fixing screws of a plastic radial fixation plate.

1 Tool for fixing screws of radial fixation plate 2 Radial fixation plate 2a Distal portion 2b Proximal portion 2d Screw insertion hole 2e Head storage portion 2f Female thread portion 2h Center tube regulating portion 2j Center tube guide portion 2k Rotation shaft portion through portion 3 Radius 3a Fracture portion 3b Radius body 3c Fracture fragment 4 Fixation screw 4a Shaft portion 4b Main screw 4c Head portion 4d Sub-screw 4j Hexalobular hole 5 Guide block 5a Distal portion 5b Proximal portion 5c Holding claw 5d Screw insertion hole 5e Center tube guide portion (guide tube guide portion)
5f Rotating shaft penetrating portion 5h Center tube regulating portion (guide tube regulating portion)
7 Main body 8 Guide tube 8g Rotation stop protrusion 8j Second engagement portion 8k Base end surface 8m Guide tube main body 8n Annular convex portion 11 Rotational force input portion 11a Flat surface portion 11b Fitting recess 12 Rotational shaft portion 12a Shaft main body 12c Screw coupling portion 12d Fitting protrusion 12e Spring locking protrusion 13 Middle tube 13a Middle tube main body 13b Through hole 13c First engagement protrusion 13d Base end surface 13e First engagement recess 13g Inclined surface 14 Outer tube 14a Outer tube main body 14b Through hole 14c Second engagement protrusion 14e Second engagement recess 14g Inclined surface 16 Fixing pin 71 Tool for fixing screw of radius fixation plate 81 Rotational force input portion 81a Flat surface portion 82 Rotational shaft portion 82a Shaft main body 82c Screw coupling portion 82j First engagement portion 82k Annular protrusion A Rotation position B Idle position

Claims (7)

A radial fixation plate fixing screw tool for rotating a fixing screw that fixes a radial fixation plate to a radius, comprising:
a rotational force input unit to which a rotational force for rotating the fixing screw is input;
a rotation shaft portion extending in an axial direction from a tip end of the rotational force input portion and rotatable relatively to the rotational force input portion;
a center cylinder having a screw coupling portion at a tip end of the rotating shaft portion protruding from the tip end, the center cylinder being disposed outside the rotating shaft portion so as to be movable in the axial direction between a rotating position and an idling position, and the center cylinder having a first engagement projection on an outer circumferential surface;
an outer cylinder that is rotatable integrally with the rotational force input portion and has a second engagement protrusion on its inner circumferential surface, the second engagement protrusion being arranged outside the middle cylinder so as to be relatively movable in the axial direction, and being capable of engaging with the first engagement protrusion and rotatable integrally with the middle cylinder when the middle cylinder is located at the rotation position, and being disengaged from the first engagement protrusion and rotatable relative to the middle cylinder when the middle cylinder is located at the idling position;
A radial fixation plate fixation screw tool comprising: The rotary shaft further includes a biasing member that biases the center cylinder in the axial direction so that the center cylinder is positioned at the rotation position.
2. The radial fixation plate locking screw tool of claim 1. The screw coupling portion of the rotating shaft portion is a hexalobular screw rotating portion that can be engaged with a hexalobular hole in a head portion of a hexalobular screw serving as the screw.
3. A tool for fixing a radial fixation plate screw according to claim 1 or 2. The rotation shaft portion and the rotational force input portion are configured as separate members.
4. A tool for radial fixation plate fixation screws according to claim 1. A radial fixation plate fixing screw tool for rotating a fixing screw that fixes a radial fixation plate to a radius, comprising:
a rotational force input unit to which a rotational force for rotating the fixing screw is input;
a rotating shaft portion that extends in an axial direction from a tip of the rotational force input portion, is rotatable integrally with the rotational force input portion, has a screw coupling portion at a tip, and has a first engagement portion on a base end side;
a guide tube that is a separate member from the rotating shaft portion, the guide tube being capable of relatively rotating and relatively moving in the axial direction when the rotating shaft portion is inserted, the guide tube being capable of contacting at its tip end with a guide tube regulating portion of a screw insertion hole of the radial fixation plate or a screw insertion hole of a screw guide block placed on the radial fixation plate, and having at its base end a second engaging portion that engages with the first engaging portion;
In addition to providing
a second rotation stopper portion that can be engaged with a first rotation stopper portion of the screw insertion hole of the screw guide block placed on the radial fixation plate , the second rotation stopper portion being provided on an outer periphery of the guide tube;
A third engagement portion is provided on a base end side of the rotating shaft portion,
a fourth engaging portion that contacts and engages with the third engaging portion at a base end side of the guide tube to restrict movement of the rotation shaft portion in a screw-in direction,
the first engaging portion and the second engaging portion engage with each other, and the third engaging portion and the fourth engaging portion come into contact with each other and engage with each other, thereby restricting the relative rotation between the guide tube and the rotating shaft portion and restricting the movement of the rotating shaft portion in the screwing direction.
Tool for radial fixation plate fixation screws. the first engagement portion is a male screw,
The second engagement portion is a female screw into which the male screw is screwed.
6. The radial fixation plate locking screw tool of claim 5. The screw coupling portion of the rotating shaft portion is a hexalobular screw rotating portion that can be engaged with a hexalobular hole in a head portion of a hexalobular screw serving as the screw.
The tool for radial fixation plate fixing screws according to any one of claims 5 to 6 .

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