JPH0725036B2 - Holding mechanism in automatic screw tightener - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sets a nose member to which a connecting band having a row of screws is set and sequentially feeding the connecting band.
It relates to an automatic screw tightener that removes the screw sent on the bit axis from the connecting band by a driver bit that is driven to rotate by a drive motor and tightens the screw to a desired part such as building material, especially the retracted position at the start of screw tightening work. The present invention relates to a holding mechanism that holds a nose member that is slid to the retracted position.

[0002]

2. Description of the Related Art Generally, in this type of automatic screw tightening machine, a screw feeding mechanism for feeding a connecting band, in which screws are mounted and supported, to the axis of a driver bit for each screw tightening operation, is a nose member. It employs a configuration that supplies screws using the initial operation. That is, slightly rotate the wheel engaged with the coupling band by one tooth from the most projecting position where the nose member is pressed against the site such as the building material where the screw is to be tightened and slid to the driver body side. One screw is positioned, and the driver bit is engaged with the screw by the stroke of the subsequent nose member so as to project outward, and the screw is driven at a desired portion by rotationally driving the bit.

For example, this type of automatic screw tightening machine is disclosed in US Pat. No. 4,590,034, and Japanese Utility Model Publication No. 60-26921.
It is disclosed in Japanese Utility Model Laid-Open No. 2-127676.

[0004]

However, in the known screw tightening machine of this type, the tip of the driver bit remains in the retracted position where it does not engage with the screw until the screw feeding operation by the wheel is completed. Therefore, there is a mechanical restriction that the tip of the bit cannot be projected so much longer than the driver main body. Therefore, there is a problem that the stroke cannot be set sufficiently long in the operation of tightening the screw while the bit engages the screw and the nose member slides into the driver body.

The above problem is particularly noticeable in a work environment where there are irregularities such as stepped portions around the screw tightening site, or when a screw hole is provided deeply from the side surface to which the screw is tightened. Is. Especially in today's construction materials where screws are tightened, the need for screw tightening work at deep holes is increasing from the viewpoint of design so that the screw head does not come out on the member surface. There is. That is, in such a case, before the screw is guided into the screw hole, the tip of the screw tightening machine hits and is blocked by the peripheral unevenness and the mating surface, so that the driver bit reaches the screw tightening site. However, the problem that the screw tightening work was impossible was unavoidable. On the other hand, for example, as a measure to increase the amount of protrusion of the driver bit, a device such as increasing the wheel diameter may be considered, but the overall size, weight, and cost of the screw tightener including the nose member that supports the wheel are increased. There were other problems such as ups.

From the background described above, the applicant of the present invention has found that a driver body having a driver bit, a driver bit driving motor for rotating the driver bit, and a screw mounted in a row on the connecting band for the driver bit shaft. A screw supply means for supplying the screw on the wire, a nose member having a chuck means for holding the screw on the axis of the driver bit, and a nose member which supports the nose member so as to be relatively slidable along the axis of the driver bit. A slide member that is slidably supported relative to the driver body, a most projecting position where the nose member projects most outwardly from the driver body, and a retracted position that moves inward of the driver body. And a nose member moving means for slidingly moving the nose member to a retracted position from an intermediate position of movement of the nose member. The nose member is slid from the most projecting position to the first step by the retracting operation by the nose member moving means, and then the nose member and the slide member are integrally moved to the retracted position. It proposes an automatic screw tightener configured to perform a second-stage sliding movement.

According to the proposed structure, the nose member is the first.
While the slide movement of the first step is performed, the feed operation of one pitch of the connecting band is performed, and not only the nose member but also the slide member is pulled in at the next slide movement of the second step. The stroke of slide movement can be lengthened,
Since the driver bit can be exposed to the outside for a longer time regardless of the diameter of the feed wheel, it is possible to freely perform the screw tightening work on the above-mentioned uneven portion which cannot be handled by the conventional machine.

In implementing the above proposed structure, a holding mechanism is required to hold the nose member and the slide member at the retracted position during the screw tightening operation. A spring that constantly urges the nose member and the slide member toward the most projecting position acts on the nose member and the slide member.
It is necessary to quickly perform the release switching operation.

As such a holding mechanism, for example, a so-called hook-engaging type conventional one in which an engaging pin or an engaging hole is provided in a spring-biased slide member and a hook member for engaging with and disengaging from the driver body is provided. Possible configurations. However, in this case, when the hook member is disengaged from the engagement pin or the engagement hole, a sufficient disengagement force is needed to overcome the spring bias, so the engagement and disengagement operation of the hook member is heavy, quick and light. I couldn't expect it to work. Further, the engagement / disengagement operation requires interlocking with the operating member for starting the screw tightening work and corresponding structure with the slide member moving to the retracted position, but there is a problem that the interlocking structure for this becomes complicated. there were.

[0010]

SUMMARY OF THE INVENTION Therefore, the present invention has been made in view of the configuration proposed above and the problems thereof.
The purpose is to provide a holding mechanism in an automatic screw tightener that can quickly and lightly hold and release the nose member and slide member at the retracted position and that has a simple structure and is easy to downsize. To provide.

In order to achieve the above object, the present invention is based on the above-mentioned proposed structure, and in order to releasably hold the nose member and the slide member, which are integrally moved to the retracted position, at the retracted position,
A rolling element that is inserted in the tubular portion of the driver body so as to be movable only in the radial direction, and a rolling element that is movably arranged along the inner peripheral surface of the tubular portion of the driver body and is radially inward. Portion of the rolling element radially inwardly of the rolling element, which is always biased to the original position to prevent the nose member and the slide member from moving to the retracted position and moves from the original position. Outside holding arranged so as to be movable along the outer peripheral surface of the tubular portion of the driver main body between the inside holding member that allows the dynamic projection and the holding position that holds the rolling element at the position protruding radially inward. A member, an operating member for moving and operating the outer holding member to the biasing position and the holding position, and an outer periphery of the slide member so as to engage with the rolling element that partially protrudes corresponding to the rolling element in the retracted position. It consists of a recess provided in the The engagement between the recess and, restrained by the outer retaining member which is operated to move the holding position, thereby proposes a holding mechanism having the configuration to hold the nose member and the slide member in the retracted position.

Further, regarding the slide mechanism of the present invention,
There is also provided a interlocking means for causing the switch means for starting the driver bit drive motor to respond to the movement operation of the outer holding member by the operation member, and the holding mechanism for actuating the switch means simultaneously with the movement operation of the operation member by the interlocking means. It is a proposal.

[0013]

According to the above-mentioned structure of the present invention, the inside and outside of the driver body are provided with rolling elements such as spheres which are inserted in the tubular portion of the driver body so as to be movable only in the radial direction. Due to the interaction of the holding members, the nose member and the slide member are restrained at a position that partially protrudes inward in the radial direction and correspondingly engage with the recess provided in the outer peripheral portion of the slide member. It can be held in the retracted position, one of the inner retaining members is operated in response to the movement of the nose member and the slide member to the retracted position, and the other outer retaining member is interlocked with the operation member for starting the screw tightening work. Thus, the holding operation and the releasing operation of the holding mechanism can be performed extremely quickly and lightly, and the structure can be simple and compact.

Further, if the operation member is interlocked with the switch means for activating the driver bit drive motor through the interlocking means, the switch means can be operated simultaneously with the moving operation of the operation member, so-called one-touch operation. This is preferable in that both operations can be performed and the configuration can be simplified.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an automatic screw tightening machine having a holding mechanism according to the present invention will be described below with reference to the drawings.

FIG. 1 shows the tip of this automatic screw tightening machine. Reference numeral 10 denotes a driver main body which accommodates a driver bit 12 along the axis XX, and 14 denotes a chuck 1.
6, a nose member provided with the screw supply mechanism 18 and a guide surface 14a for guiding the connecting band 22 made of synthetic resin in which the screws 20 are arranged at intervals, and 24 is the driver body 10 and the nose member 14 And a slide member 26 interposed between the driver body 10, the nose member 14 and the slide member 24.
It is a cooperation mechanism that selectively performs fixing and releasing between members.

In FIG. 1, the nose member 14 is at the most projecting position, and this position is the state in which the nose member 14 projects in the direction most distant from the driver body 10 (rightward in the figure), and the screw tightening operation starts. Alternatively, it is in a dormant state. At the most projecting position, the nose member 14 has a stopper 28, which is a screw head screwed into the member 14, abutting one end of the opening 30 of the slide member 24 to regulate the position in the projecting direction, and the slide member 24. Is fixed to the driver main body 10 by the cooperation mechanism 26 in a relative slidable state along the axis XX.

The linkage mechanism 26 is a rolling element 3 made of a sphere.
2. The sleeve wall 24 of the slide member 24 that accommodates the same
The sleeve wall 10a forming the tubular portion of the driver body 10 that is in sliding contact with the through hole 34 formed in a and the outer peripheral surface of the sleeve wall 24a
And a recess 38 formed on the outer peripheral surface of the sleeve wall 14b of the nose member 14 slidingly contacting the inner peripheral surface of the sleeve wall 24a.

When the nose member 14 is at the most protruding position,
The rolling element 32 is not aligned with the recess 38 of the nose member 14, but is aligned with the recess 36 of the driver body 10 and is partially engaged therewith as shown in the drawing.
Thus, the slide member 24 and the driver body 10 are fixed so as not to move relative to each other as described above. In this embodiment, the linkage mechanisms 26 including the rolling elements 32 are provided one by one in a diametrically opposed manner. Each of the recesses 36, 38 is a truncated cone-shaped hole that partially receives the spherical surface of the rolling element 32,
As shown in the figure, the peripheral wall surface of the recess is slightly inclined so as to open outward, and this inclined surface imparts a component force for pushing the rolling element 32 outward. Thereby, a smoother switching movement of the rolling element 32 is possible.

The driver body 10, the nose member 14 and the slide member 24 are designed so as not to rotate relative to each other around the axis XX. That is, the opening 28 of the slide member 24 into which the stopper 28 on the nose member 14 has entered.
Has a width that allows the stopper 28 to slide exactly in the axial direction, so that the relative rotation of the two members 14 and 24 is prevented by this relationship. On the other hand, a stop screw 40 is screwed into the sleeve wall 10a of the driver body 10 from the outside, and the tip end portion of the stop screw 40 is slidably attached to the slide member 24.
Is engaged with a guide groove 42 formed on the outer peripheral surface of the sleeve wall 24a in the direction of the axis XX, and the width of the groove 42 is dimensioned to just slide the tip of the screw 40. Due to this relationship, relative rotation of both members 10 and 24 is prevented. It should be noted that, in FIG. 1, only the portions where the stop screw 40 and the guide groove 42 are provided are shown in different sectional views in different rotation directions for the sake of explanation.

FIG. 2 shows the appearance of the automatic screw tightening machine according to the present invention in a screw tightening operation state. As shown in the drawing, the tip of the driver bit 12 can be projected longer than the nose member 14 and the chuck 16, so that the screw tightening portion 44a of the mating member 44 such as a building material to be screwed is located at the deep hole position. In any case, the site 44
Up to a, it can be introduced with the screw 20 attached to the tip. On the outer circumference of the cylinder of the driver body 10, a locking ring 46 is movable along the outer peripheral surface by a predetermined distance.
Is provided, one end of the operating rod 50 enters the elongated hole 48 formed in the axial direction, and the other end is rotatably supported by the pivot shaft 52 at the rear end of the driver body 10. It is connected to the operation member 54. A pair of elongated holes 48 are formed in the diametrical direction, and correspondingly, the operating rod 50 extends from the operating member 54 in a bifurcated shape to correspond to each elongated hole 48. In the figure, the operating member 54, together with the operating rod 50 and the locking ring 46, is shown for the sake of convenience in a non-operating state or a rest state of the screw tightener. The operation member 5
When 4 is pressed in the direction of the arrow against the compression coil spring 53 at the start of the screw tightening work, the start switch button 56, which is a switch means disposed on the driver body 10 below the operating member 54, is simultaneously pressed. As a result, the driver bit driving motor 58 electrically connected to the switch button 56 is started, and the driver bit 12 is rotationally driven. In the embodiment, the operation member 5
The operation of the switch 4 and the switch button 56 is interlocked by mechanical contact, and the mutual contact portions constitute the interlocking means, but a member such as a link may be separately used as the interlocking means.

A holder 59 attached to the driver body 10.
The tip 59a of the guides the long connecting strip 22 between the connecting strip reel (not shown) and the nose member 14, but the holder and other parts are known.

The screw supply mechanism 18 shown in FIGS. 1 and 3
In the figure, reference numeral 60 is a feed wheel, 62 is a feed operation lever described later, and 64 is a reverse rotation preventing pawl similarly described later.
The feed wheel 60 has teeth on its outer periphery that engage with the side edges of the coupling band 22, a pair is provided corresponding to each side edge, and the driver bit 12 passes through a space 66 between the pair of wheels. Has become. As shown in FIG. 3, the driver bit 12 passes through the space 66 along an axis YY that connects the support shafts 68 of the individual wheels 60 supported by the nose member 14 along the axis XX.

Chuck 16 attached to nose member 14
As shown in FIG. 3, a pair of openable and closable shafts 70 on the nose member 14 are used as fulcrums, and are normally closed by the compression coil springs 72.

In FIG. 4, 74 is a nose member moving mechanism which is a main part of the slide mechanism according to the present invention for moving the nose member 14, and 76 is power from the driver bit driving motor 58 for the nose member moving mechanism 74. A clutch mechanism for selectively engaging / disengaging the clutch mechanism with a common power source as a common power source. After disengaging the clutch mechanism 76 once, the clutch mechanism 76 is automatically operated in response to the start of rotational driving of the driver bit. An automatic return mechanism for returning to the clutch engagement state, 80 is the locking ring 46 described in FIG.
Is a holding mechanism that holds the nose member 14 together with the slide member 24 at the most retracted position in the driver body 10 direction.

The driver bit drive shaft 82, which serves as the power source of each of the above mechanisms, is connected to the motor shaft 58a of the motor 58 at one end (the left end in FIG. 4) and the driver bit 12 at the other end (the right end in FIG. 4). Pin 84 on the base end
Are detachably operably connected to each other. A driven shaft 86 having a cylindrical shape is fitted on the drive shaft 82, and the rotary member 8 is provided adjacent to the driven shaft 86 on the outer peripheral portion of the drive shaft 82.
8 is attached so as to be integrally rotatable. A compression coil spring 89 is stretched between the driver body 10 and the tip of the sleeve wall 14b of the nose member 14, whereby the nose member 14 is always urged toward the most protruding position.

First, the nose member moving mechanism 74 will be described with reference to FIGS. 4 and 11. 90 is a take-up drum arranged concentrically with the driver bit drive shaft 82, 92 is a plurality of planetary gears connected to the take-up drum 90 by a shaft 94, and 96 is integral with the driver body 10. Is a housing extending in a tubular shape along the axis X-X. The housing 96 has an internal gear section 96a that meshes with the planet gears 92. Each planet gear 92 is externally meshed with a sun gear portion 86a formed on the driven shaft 86. As shown in FIG. 11, the support shaft 9 is attached to the housing 96.
A pulley 100 is rotatably supported in a plane parallel to the axis X-X via a shaft 8. A string-shaped body 102 formed of a flexible wire rope or the like is wound around the cylindrical outer peripheral surface of the winding drum 90, and one end of the string-shaped body 102 is fixed to the drum 90. Pulley 1
The direction is changed by 90 degrees through 00 to be stretched in the driver main body 10 in parallel with the axis X-X, and the other end is connected to the nose member 14 as shown in FIG. That is, the other end of the cord-like body 102 is attached by the fixed terminal 104 at the end wall 14c of the nose member 14. In addition, each cord-shaped body 1
Since 02 passes through the passage 103 formed in the housing 96 in the portion suspended by the pulley 100, it does not interfere with the housing 96.

When the winding drum 90 rotates in one direction, the cord-shaped members 102 start pulling the nose member 14 from the most projecting position (FIG. 1) via the pulley 100 accordingly. . When the driven shaft 86 is rotated by the winding drum 90 via the clutch mechanism 76, this rotation causes the rotation of the sun gear 86a, the planetary gear 92, and the internal gear 9.
The rotation speed is transmitted through the shaft 94 in a state where the rotation speed is converted by the planetary gear mechanism 6a.

Next, the clutch mechanism 76 will be described with reference to FIGS. 4, 6 and 12. Reference numeral 106 denotes a collar-shaped operation member which is fitted in the driven shaft 86 so as to be movable in the axial direction, and the pressing portion 1 which protrudes inward in a ring shape on the inner peripheral surface side.
06a and an outer peripheral surface of the driven shaft 86 have a release portion 106b that forms a space, and an O-ring 108 is provided on the outer peripheral surface side for slidingly contacting the tip inner surface 96b of the housing 96 with a predetermined frictional force. The spiral uneven portion 10 associated with an automatic return mechanism 78 described later is formed on the outer peripheral surface of the small diameter.
6c is integrally formed.

A pair of through holes 110 are formed in the driven shaft 86 in the diameter direction, and a spherical rolling element 112 is housed in each through hole.
Corresponding to this, the driver bit drive shaft 82 is particularly shown in FIG.
2, a clutch shaft portion 8 having a cutout portion 82a formed therein.
2b is provided, and the driver bit drive shaft 82 and the driven shaft 86 are coupled / disengaged in the form of a roller clutch via the rolling element 112. That is, the operating member 106
4 is located at the position shown in FIG.
Of the clutch mechanism 76 in the clutch engagement state shown in FIG. 12, whereby power is transmitted from the shaft 82 to the shaft 86. As a result, a winding operation for pulling in the nose member 14 by the nose member moving mechanism 74 is performed. On the other hand, the operating member 106 moves to the left from the position of FIG. 4 to move the release portion 1 onto the rolling element 112 as shown in FIG.
When 06b is positioned, the rolling element 112 is allowed to project outward, and as a result, the clutch mechanism 76 is switched to the clutch disengaged state shown by the chain line in FIG. This makes axis 8
No power is transmitted from the driven shaft 86 to the driven shaft 86. As a result, the driven shaft 86 becomes free, and the nose member moving mechanism 74 performs a rewinding operation during this period, as will be described later.

In the clutch mechanism 76, the switching operation from clutch engagement to disengagement is performed by the operation pin 114. A pair of the pins 114 are diametrically supported by the rotating member 88 so as to be slidable in the direction of the axis XX, and the inner end enlarged portion 114a is in contact with the inner wall of the rotating member 88 at all times, that is, in the clutch engaged state, as shown in FIG. It is in the most protruding state. These pins 114, when the nose member 14 is retracted, end wall 14c of the member as shown in FIG.
And is pushed inward from the rotating member 88 from the most protruding state. As a result, the operating member 106 moves to the left in FIG. 4, and the release portion 106b moves to the rolling element 1
12 and the clutch is disengaged.

The switching from the clutch disengaged state of the clutch mechanism 76 to the clutch engaged state shown in FIG. 4 is performed by the automatic return mechanism 78, and will be described below with reference to FIGS. 4 and 13 in particular. As described above, the spiral concavo-convex portion 106c is formed on the small-diameter outer periphery of the operation member 106, and correspondingly, the spiral concavo-convex portion 106c is formed on the rotary member 88, particularly in FIG.
As shown by 3, a pair of claw members 116 facing each other in the diametrical direction.
Is pivotally supported by a shaft 118, and these claw members 1
16 is an engaging tooth 1 at the end of one arm with the shaft 118 as a fulcrum.
16 a and the other arm 116 b is formed to be long, and is configured to be rotatable from the solid line position (non-engaging position) shown to the chain line position (engaging position) by centrifugal force when the rotating member 88 rotates. . Only the engaging teeth 116a are formed narrow according to the groove width of the valley portion so that they can be engaged with the valley portion of the spiral uneven portion 106c. The other arm 116b does not enter the valley portion even if it contacts the mountain portion of the uneven portion 106c. Further, the claw member 116 is in the engagement position and the other arm 1
16b is in a state of protruding outward as shown by a chain line in FIG. 13, but when the nose member 14 is retracted, the sleeve wall 14b is fitted into the component portion including the rotating member 88 by the outside. The taper edge 14d formed at the tip of the sleeve wall 14b is pushed inward by the cam action. Therefore, the claw member 11
6 is forcibly removed from the spiral uneven portion 106c. In FIG. 13, the passing position of the sleeve wall 14c is shown by a chain line.

As described above, the release portion 1 of the operating member 106.
At a clutch disengagement position 06b corresponding to the rolling element 112, the driven element 86 is in a free state, during which the rewinding operation of the nose member moving mechanism 74 is performed by the bias of the spring 89, and the winding drum 90 is reversed. It rotates, and this also reversely rotates the driven shaft 86 via the planetary gear mechanism. Then, along with this, the operation member 106 may also follow and rotate, but in this case, the O-ring 108 is stopped due to the frictional force between the O-ring 108 and the inner surface 96b of the housing, and is left stationary.

In the above state, when the driver bit drive shaft 82 rotates with the start of the screw tightening work, the rotating member 88 also rotates, and the claw member 116 is engaged with the spiral uneven portion 106c by the centrifugal action. Then, since the rotating member 88 continues to rotate in this state, the spiral concavo-convex portion 106 is formed.
Due to the engagement relationship between c and the claw member 116, the operation member 106 is relatively moved in the axial direction on the driven shaft 86 in a screw feed manner. During this time, the operating member 106 is the O-ring 108.
The rotation is stopped by the action of. Operation member 106 described above
Is moved until the pressing portion 106a reaches the rolling element 112, and when the clutch engagement state is brought about by this, the driven body 86 starts to rotate and the operating member 106 also rotates, so that the relative movement of the operating member 106 in the axial direction. The movement stops and the clutch engagement state is maintained. In this way, the clutch mechanism 7
6 can be automatically returned to the clutch engagement state at the start of the screw tightening work by the automatic return mechanism 78.

Next, the holding mechanism 80 will be described with reference to FIGS. 4 and 6. Locking ring 46 and driver body 1
The slider 120 having the end portion of the operation rod 50 attached thereto is inserted into the space between the outer peripheral surface of the slider 0 and the outer peripheral surface so as to be movable in the axial direction, and the compression coil spring 122 is inserted between the slider 120 and the locking ring 46. Has been done. Driver body 1
A through hole 124 is formed in the sleeve wall 10a that forms a cylindrical portion of 0, and a spherical rolling element 126 is inserted therein so as to be movable only in the radial direction, and the locking ring 46 that serves as an outer holding member is pressed on the outside. Protrusion is suppressed by the portion 46a and inside by an operation ring 128 which is an inner holding member which is in sliding contact with the inner peripheral surface of the cylindrical portion of the driver body 10. The operation ring 128 is biased toward the original position shown in FIG. 4 by the compression coil spring 130, and is held against the spring bias by an appropriate stopper (not shown).

When the operation member 54 is pushed down against the spring 53 as shown in FIG.
This operation causes the operating rod 50 to move the slider 120 to the position shown in FIG.
At, the spring 122 is compressed by moving it to the right. As a result, the pressing portion 46a of the locking ring 46 continues to apply an inward pressing force to the rolling element 126 that is partially exposed.
In this state, when the nose member 14 is retracted to the retracted position integrally with the slide member 24 by the rotation of the driver bit 12 and the operation of the nose member moving mechanism 74 corresponding thereto, as shown in FIG. Causes the operating ring 128 to retract from the original position against the spring 130, and causes the recess 132 formed on the outer peripheral surface of the sleeve wall 24a of the slide member 24 to correspond to the rolling element 126. As a result, the rolling element 126 is assisted by the urging force of the pressing portion 46a of the locking ring 46 at the pressing position, and the recess 132 is formed.
Partially enrolled in. At the same time, the locking ring 46 rapidly moves to the holding position where it abuts against the projecting edge 10b of the driver body 10 shown in FIG. 6 by the bias of the spring 122, and the lower end locking portion 46b moves upward of the rolling element 126. Since the protrusion is prevented, the rolling element 126 is restrained in the engagement state with the recess 132. Therefore, the slide member 24 and the nose member 14 are securely held in this retracted position during the screwing operation of the driver.

When the screwing operation of the driver is completed and the operating member 54 (FIG. 2) is released, the operating ring 50 returns the locking ring 46 to the pressing position of FIG. It comes off from the rolling element 126, and instead, the pressing portion 4
6a is located again. As a result, the rolling element 126 receives a force outward in the radial direction from the concave portion 132 in response to the action of the slide member 24 returning in the projecting direction by the bias of the spring 89, and the rolling element 126 escapes from the concave portion 132 and the held state is eliminated. To do. As a result, the operation ring 128 also returns to the original position and returns to the state of FIG.

The edge of the groove of the recess 132, particularly the left edge in FIG. 6, in other words, the edge 132a on the side that directly contacts the rolling element 126 for engagement and disengagement, is tapered as shown. As a result, when the rolling element 126 escapes, the tapered surface functions as a cam and a larger component force in the escape direction can be applied to the rolling element 126, so that a smooth switching operation is performed. Further, in the same meaning, the pressing portion 46 of the locking ring 46 is
Also, a has an edge with a tapered structure.

Next, the screw feeding operation of the screw supply mechanism 18 shown in FIGS. 1 and 2 will be described with reference to FIGS. Corresponding to each feed wheel 60, a feed actuating lever 62 is rotatably supported by a support shaft 134 on a slide member 24 at a proximal end thereof, and is urged clockwise by a spring 136 in the drawing, and the slide member 2
It is held against the spring 136 by a stopper 138 provided on the upper part of the table 4. A plurality of ribs 140 are radially provided integrally with the feed wheel 60 on the side of the feed wheel 60 by the number of feed pitches (six in the embodiment), and one engaging surface has a substantially mountain shape or V-shaped first and second inclined surfaces 140a and 140b are formed. The roller 141 at the end of the actuating lever 62 is engaged with the inclined surfaces 140a and 140b.

At the initial position of the feed shown in FIG. 7, the roller 142 corresponds to the first inclined surface 140a, and by the relative movement of the nose member 14 and the slide member 24 from here,
While the roller 142 presses the first inclined surface 140a, the wheel 60 is rotated in the clockwise direction (feed direction) indicated by the arrow. During this time, the lever 62 contacts the stopper 138 to move the roller 142 in a straight relative direction parallel to the axis XX. As the rotation of the wheel 60 progresses, the roller 14
In the case of No. 2, the correspondence naturally shifts from the first inclined surface 140a to the second inclined surface 140b, and the state goes toward the inside of the rib 140 in the radial direction, and the feed for one pitch shown in FIG. The next upper screw 20 is set at the feed position along the axis XX.

Since the inclined surfaces 140a and 140b are formed in this manner, the direction of action of the reaction force from the rib 140 on the roller 142 always passes in the vicinity of the support shaft 134 of the lever 62. Lever 62 during the feeding operation
Does not move against the spring 136 in a direction away from the engagement with the rib 140.

After the feed for one pitch is completed, the nose member 14
In the returning operation in which the roller relatively moves in the direction away from the slide member 24, as shown in FIG. 9, the roller 142 slides on the surface 140c on the opposite side of the adjacent next rib 140 and resists against the spring 136. While rotating in the clockwise direction, it escapes and operates so as to come off the rib 140, and corresponds to the next rib 140 at the initial position shown in FIG. 7. During this time,
The wheel 60 is restrained in the reverse rotation direction by the reverse rotation prevention 64, and holds the screw 20 set at the feed position at that position.

A pair of reverse rotation preventing claws 64 are provided corresponding to each wheel 60, and as shown in FIG.
The spring 1 is rotatably supported by the upper support shaft 142 and
It is urged in one direction (clockwise in FIG. 10) by 44, so that one arm 64a of the bifurcated shape is applied to each wheel 6
The toothed wheel 146, which is integrally provided on the side surface of No. 0, is elastically engaged. The number of teeth around the wheel 146 is equal to the pitch of the wheel 60 (6 in the embodiment).
), Correspondingly provided. As the wheel 146 rotates during the feeding operation, the arm 64a of the pawl 64 overcomes the teeth against the spring 144 and returns to the engaging position of the wheel 146 again. In the state where the one-pitch feed operation is completed, the arm 64a is placed in the proximity position immediately after overcoming the corresponding tooth on the wheel 146 as shown in FIG. It is blocked by contact with 64a.

The other arm 64b of the reverse rotation preventing claw 64 prevents the feed wheel from rotating too far beyond a predetermined pitch. Although the reverse rotation direction is blocked as described above, for example, when the feed wheel 60 is rotationally driven by one pitch by the relative movement operation of the nose member 14 and the slide member 24, the wheel 60 becomes particularly abrupt. If the screw is rotated, it may rotate more than 1 pitch due to inertia or the like, and the screw may not be accurately set at the feed position. In order to prevent this, the reverse rotation preventing claw 64 is further provided with an arm 64b. When the wheel 60 is rapidly rotated in the feeding direction indicated by the arrow, the toothed wheel 146 that rotates integrally with this is engaged. One arm 64a doing
Against the spring 144, as shown by the chain line, the reverse rotation preventing claw 64 is rotated more counterclockwise than in the normal state. The other arm 64b is set in such a positional relationship that it does not enter the locus of the teeth of the toothed wheel 146 during a normal slow feeding operation. As shown by, the state enters the locus and comes into contact with the corresponding tooth. Since this rotational position is made to coincide with the one-pitch feed completed state, when the wheel 60 tries to rotate too much, the other arm 64b is prevented from coming into contact with the teeth.

The relative movement of the three members of the nose member 14, the slide member 24, and the driver body 10 in a series of screw tightening operations in the automatic screw tightener constructed as described above will be collectively described below.

In the state immediately before the start of the screw tightening work or in the unused condition, the screw tightener has the nose member 14 at the most projecting position as shown in FIG. It is in a fixed state. When the screw tightening work is started from this state, the clutch mechanism 76 is brought into a coupled state, and the winding drum 9
The string-shaped body 102 is wound around the drum by the rotation of 0, and the string-shaped body 102 is pulled by this, and the force is transmitted to the nose member 14 via each pulley 100. Is drawn from the most projecting position as the first stage drawing stroke, and as shown in FIG. 1, during the stroke A up to the position (intermediate position) shown in FIG. 5 where the concave portion 38 matches the rolling element 32 (intermediate position). The screw feed of 1 pitch is performed by 18. Then, here, the nose member 14 and the slide member 24 are fixed to each other by the switching operation of the cooperation mechanism 26, and are integrally drawn further by the continuous rotation of the winding drum 90, and the holding mechanism 80 is held in the recess 132 of the slide member 24. At the position where the rolling element 126 is engaged (the retracted position), the retracting operation ends and the clutch is disengaged. During this period, both members 14 and 24 are further retracted by the stroke B shown in FIG. 6 as the second stage retracting stroke. On the other hand, since the driver bit 12 is only rotated with respect to the driver body 10 and is fixed in the direction of the axis X-X, the tip portion of the driver bit 12 is moved by the second step retracting stroke as shown in FIG. Nose member 1
Therefore, the screw 20 held at the tip portion can be easily tightened at a portion having an unevenness such as a deep hole as shown in FIG.

[0047]

As described above, according to the present invention, rolling elements such as spheres, which are inserted in the tubular portion of the driver body so as to be movable only in the radial direction, are arranged inside and outside the driver body. By the interaction of the arranged inner and outer holding members,
The nose member and the slide member are brought to the retracted position by restraining the rolling element in a position that partially protrudes inward in the radial direction and correspondingly engaging with a recess provided in the outer peripheral portion of the slide member. It can be securely held, one inner holding member is operated in response to the movement of the nose member and the slide member to the retracted position, and the other outer member is interlocked with the operating member for starting the screw tightening work. The corresponding structure can be easily made, and the holding mechanism and the releasing operation of the holding mechanism can be performed extremely quickly and lightly by using the rolling element, and further, the structure is simple and the structure can be made compact.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a tip end portion of an embodiment of an automatic screw tightener having a holding mechanism according to the present invention.

FIG. 2 is an overall external view showing the automatic screw tightener shown in FIG. 1 in a screw tightening operation state in which a driver bit is projected.

3 is an axial line X- of the driver bit at the tip shown in FIG.
FIG. 3 is a vertical sectional view taken along line XIII-XIII.

FIG. 4 is an enlarged vertical sectional view of a central portion of the automatic screw tightening machine shown in FIG.

FIG. 5 is an operation explanatory view corresponding to FIG. 1 showing the nose member in the intermediate position.

FIG. 6 is an operation explanatory view of the main part of the automatic screw tightening machine shown with the nose member in the retracted position together with the slide member.

FIG. 7 is a longitudinal sectional view of an essential part of an automatic screw tightening machine showing an initial operation of a screw supply mechanism.

FIG. 8 is a view corresponding to FIG. 7 showing a feeding completion operation of the screw supply mechanism.

FIG. 9 is a view corresponding to FIGS. 7 and 8 showing the returning operation of the screw supply mechanism.

FIG. 10 is a schematic diagram of a rotation control mechanism of a feed wheel in the screw supply mechanism.

11 is a transverse cross-sectional view taken along line 11-11 of FIG.

12 is a cross-sectional view taken along line 12-12 of FIG.

13 is a transverse sectional view taken along line 13-13 of FIG.

[Explanation of symbols]

 10 Driver Main Body 10a Sleeve Wall (Cylinder) 12 Driver Bit 14 Nose Member 18 Screw Supply Mechanism 24 Slide Member 26 Cooperating Mechanism 46 Locking Ring (Outside Holding Member) 46a Pressing Part 46b Lower End Locking Part 50 Operation Rod 54 Operation Member 56 Switch button 74 Nose member moving mechanism 76 Clutch mechanism 78 Automatic return mechanism 80 Holding mechanism 126 Rolling element 128 Operation ring (inner holding member)

Claims (2)

[Claims] 1. A driver body having a driver bit,
A driver bit drive motor for rotating the driver bit, a screw supply means for supplying a screw mounted and mounted on the connecting band onto the axis of the driver bit, and a chuck means for holding the screw on the axis of the driver bit. A nose member that is provided, a slide member that supports the nose member slidably along the axis of the driver bit, and is slidably supported relative to the driver body, and the nose. A nose member moving means for slidingly moving the member between the most projecting position projecting most outward from the driver body and the retracted position moving inward of the driver body, and an intermediate position of movement of the nose member. The nose member is provided with a cooperation means for cooperatively fixing the nose member and the slide member to the retracted position, and the nose portion is moved by the retracting operation by the nose member moving means. In the automatic screw tightener configured to perform the first-stage sliding movement from the most projecting position, and subsequently the nose member and the sliding member integrally perform the second-stage sliding movement to the retracted position; The nose member and the slide member, which have moved integrally to the position, are releasably held at the retracted position, the rolling element being inserted in the tubular portion of the driver body so as to be movable only in the radial direction, and the driver. It is arranged so as to be movable along the inner peripheral surface of the tubular portion of the main body, and is constantly biased to an original position that prevents the rolling elements from protruding radially inward, and to the retracted position of the nose member and slide member. And an inner holding member that moves from the original position in response to the movement of the rolling element to allow a partial protrusion of the rolling element inward in the radial direction, and a pressing force that pushes the rolling element inward in the radial direction. Position and the rolling element An outer holding member that is movably disposed to the holding position for holding a position protruding radially inwardly along the outer peripheral surface of the cylindrical portion of the driver main body,
An operating member for moving and operating the outer holding member to the pressing position and the holding position, and an outer peripheral portion of the slide member so as to engage with the rolling element corresponding to the rolling element and partially protruding at the retracted position. The outer holding member moved to the holding position restrains the engagement between the rolling element and the recess, and thereby holds the nose member and the slide member at the retracted position. A holding mechanism in the characteristic automatic screw tightening machine. 2. An interlocking device is provided for causing the switch device for activating a driver bit drive motor to respond to a moving operation of the outer holding member by the operating member, and by the interlocking device, the switching device is operated simultaneously with the moving operation of the operating member. The holding mechanism according to claim 1, which is activated.