JPH0725035B2 - Clutch mechanism of 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 is related 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 power, and tightens the screw to a desired part such as a building material, especially the driving force from the driver bit drive shaft. Connection of drive transmission force to the nose member that slides after receiving transmission
The present invention relates to a clutch mechanism that disconnects.

[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.

In view of the above background, the applicant of the present invention has a driver body having a driver bit that is rotationally driven, a driver bit drive shaft provided in the driver body, and screws that are mounted and supported on a connecting band. A screw supply means for supplying on the axis of the driver bit, a nose member provided with a chuck means for holding the screw on the axis of the driver bit, and a relative slidability of the nose member along the axis of the driver bit. A slide member that supports and is slidably supported relative to the driver body, and a nose member that is most outwardly protruded from the driver body by receiving a driving force from the driver bit drive shaft. Nose member moving means for slidingly moving from the protruding position to the retracted position moved inward of the driver body, the nose member moving means and the driver A clutch mechanism for connecting / disconnecting driving force transmission to / from the babbit drive shaft, wherein the engaging operation of the clutch mechanism causes a retracting operation by the nose member moving means, whereby the most protruding position of the nose member. The first stage is slid and then the second stage is slid to the retracted position of the nose member and the slide member, and when the retracted position is reached, the disengagement operation of the clutch mechanism is performed. We are proposing an automatic screw tightening machine.

According to the proposed structure, the nose member is the first.
While the slide movement of the first stage is performed, the feed operation of one pitch of the connecting body is performed, and in the slide movement of the next second stage, not only the nose member but also the slide member is pulled in together. 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 embodying the above proposed structure, the nose member reaches the retracted position in the case of a clutch mechanism for connecting and disconnecting the driving force transmission between the nose member moving means and the driver bit drive shaft. At the same time, it is necessary to cancel the transmission of the driving force to the nose member moving means and, on the other hand, to transmit the driving force to the nose member moving means so as to slide the nose member from the most projecting position in response to the start of the screw tightening work. is there.

As such a mechanism, for example, a structure in which a sensor for detecting the position of the nose member is provided and the actuator is operated by receiving a signal from the sensor is conceivable.
Since an electric controller for moving the actuator has to be installed, there is a problem that it is difficult to design the automatic screw tightening machine as a whole in a compact size and the cost becomes high. When mechanical means is used instead of such electrical means, the members are normally moved in the axial direction in order to engage and disengage the clutch, but in order to achieve an overall compact design. Was expected to have a structure in which the amount of movement in the axial direction was suppressed as much as possible.

[0010]

SUMMARY OF THE INVENTION Therefore, the present invention has been made in view of the configuration proposed above, and its purpose is to:
An object of the present invention is to provide a clutch mechanism for an automatic screw tightening machine, which facilitates downsizing of the entire automatic screw tightening machine and ensures reliable operation.

In order to achieve the above object, the present invention is based on the above-mentioned proposed structure, and a clutch mechanism is operatively connected to the nose member moving means and a driven shaft for operating the nose member moving means by rotation, An operating member movable between an operating position for rotationally coupling the driven shaft to the driver bit drive shaft and an inactive position for separating rotation transmission of both shafts, and an operating member cooperating with the nose member, First response means that operates in response to the arrival at the retracted position to move the operating member to the inoperative position; and the operating member from the inoperative position to the operating position in response to the rotation start of the driver bit drive shaft. The present invention proposes a clutch mechanism for an automatic screw tightener, which is characterized by a second response means to be moved and a configuration including the second response means.

Further, regarding the above-mentioned clutch mechanism of the present invention,
Further, the second response means includes a rotating member that rotates integrally with the driver bit drive shaft, a claw member pivotally supported on the rotating member, and a claw member formed on the outer periphery of the operating member. It is also proposed to provide a configuration including a spiral concave-convex portion that can be selectively engaged.

According to the structure of the present invention, when the nose member moving means moves the nose member to the retracted position, the first response means engages with the operating member in response to the position of the nose member. Then, the clutch is moved to the inoperative position, the clutch is disengaged, the driving force transmission to the nose member moving means is interrupted, and the retracting operation of the nose member is completed.
On the other hand, in order to retract the nose member at the most protruding position in the unused state in response to the start of the screw tightening operation, the second response means is actuated by the rotation of the driver bit drive shaft and the operating member is moved from the inoperative position to the actuated position. To the clutch engagement state, the driving force is transmitted to the nose member moving means, and the retracting operation of the nose member is started.

Further, the second response means is automatically moved to the operating position by turning together with the rotating member in a state where the claw member pivotally supported on the rotating member is engaged with the spiral uneven portion on the operating member. The operation member is moved back.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an automatic screw tightening machine having a clutch 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
a, a through hole 34 formed in a, a recess 36 formed in the inner peripheral surface of the sleeve wall 10a of the driver body 10 slidingly contacting the outer peripheral surface of the sleeve wall 24a, and a sleeve of the nose member 14 slidingly contacting the inner peripheral surface of the sleeve wall 24a. It has a recess 38 formed on the outer peripheral surface of the wall 14b.

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 arranged on the driver main body 10 at the lower position of the operation member 54 is simultaneously pressed, whereby A driver bit driving motor 58 electrically connected to the switch button 56 is started to have an interlocking structure for rotationally driving the driver bit 12.

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
Is in the position (operating position) of FIG. 4, the pressing portion 106a prevents the rolling element 112 from projecting outward, and as a result,
The clutch mechanism 76 is placed in the clutch engagement state shown in FIG. 12, and 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 operation member 106 moves to the left from the position of FIG. 4 and moves to the position shown in FIG. 6 (inoperative position).
The release portion 106b is located on the rolling element 112,
As a result of allowing the rolling elements 112 to project outward, the clutch mechanism 76 switches to the clutch disengaged state shown by the chain line in FIG. As a result, power is not transmitted from the shaft 82 to the driven shaft 86, and as a result, the driven shaft 86 becomes free, and during this time, the rewinding operation is performed in the nose member moving mechanism 74 as 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. When the nose member 14 is retracted and reaches the retracted position, these pins 114 come into contact with the end wall 14c of the member as shown in FIG.
It is designed to be pushed inward of 8. This allows
The operating member 106 moves to the left in FIG.
06b is located on the rolling element 112, and the clutch is disengaged. That is, the operation pin 114 constitutes a first response means that moves the operation member 106 from the operating position to the inactive position in response to the movement of the nose member 14 to the retracted position and causes the clutch disengagement.

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
Although 16b is in a state of projecting outward as shown by a chain line in FIG. 13, when the nose member 14 is retracted, the sleeve wall 14b is fitted into the component including the rotating member 88 by the outside. The tapered edge 14d formed at the tip of the sleeve wall 14b is pushed inward by the cam action. Therefore, the claw member 116
Is forcibly disengaged 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, and during this time, the rewinding operation of the nose member moving mechanism 74 is performed by the biasing of the spring 89, and the winding drum 90 moves. The reverse rotation causes the driven shaft 86 to also reversely rotate via the planetary gear mechanism. Then, there is a possibility that the operation member 106 will also follow up with this,
Here, rotation of the O-ring 108 is stopped by a frictional force between the O-ring 108 and the inner surface 96b of the housing, and the O-ring 108 remains 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. That is, when the screw tightening work is started, the automatic return mechanism 78 responds to the rotation of the driver bit drive shaft 82 to move the operating member 106 from the inoperative position to the operating position to engage the clutch by the second response means. Make up.

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
No. 0 has a through hole 124 formed therein, in which a spherical rolling element 126 is housed, and is slid on the outer peripheral surface of the driver body 10 by the pressing portion 46a of the locking ring 46 on the outside. Protrusion is suppressed by the operating ring 128 that contacts. The operation ring 128 is a compression coil spring 130.
Is biased toward the original position shown in FIG. 4 and is held against the spring bias by an appropriate stopper (not shown).

When the operation member 54 is pushed down as shown in FIG. 2 at the start of the screw tightening work, the operation causes the operation rod 50 to move the slider 120 to the right in FIG. 4 to compress the spring 122. . As a result, the rolling element 126 in which the pressing portion 46a of the locking ring 46 is partially exposed.
Continue to apply inward pressing force to. In this state, when the nose member 14 is retracted to the retracted position together with the slide member 24 by the rotation of the driver bit 12 and the operation of the nose member moving mechanism 74 corresponding to this, FIG.
As indicated by, the slide member 24 retracts the operation ring 128 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 partially engaged with the recess 132 by the urging force of the pressing portion 46a. Along with this, the locking ring 4
6 rapidly moves to the locking 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 prevents the rolling element 126 from protruding upward. 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 operation member 54 (FIG. 2) is released, the operation rod 50 correspondingly returns the locking ring 46 to the original position of FIG. 4 and the locking portion 46b is released. It comes off from the rolling element 126, and instead, the pressing portion 46.
a is located again. As a result, the rolling element 126 has the recessed portion 1 depending on the action of the slide member 24 returning in the protruding direction.
It escapes from 32 and the holding state is eliminated. 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 can give a larger component force in the escape direction to the rolling element 126, so that a smooth switching operation is performed. In the same sense, the pressing portion 46a of the locking ring 46 has a tapered edge.

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. Corresponding at the initial position shown by the rib 140 by escaping while rotating clockwise. 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, in response to the movement of the nose member to the retracted position, the operating member is moved from the operating position to the non-operating position by the first response means to disengage the clutch. When the screw tightening operation is started, the second response means moves the operating member from the inoperative position to the operating position in response to the rotation of the driver bit drive shaft to form the clutch engagement state. Therefore, various mechanical effects can be achieved, such as a compact structure with only mechanical parts without using an electric control device such as a sensor, and reliable engagement and disengagement of the clutch.

[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 clutch 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 12 Driver Bit 14 Nose Member 18 Screw Supply Mechanism 24 Sliding Member 26 Cooperating Mechanism 74 Nose Member Moving Mechanism 76 Clutch Mechanism 78 Automatic Return Mechanism 80 Holding Mechanism 82 Driver Bit Drive Shaft 86 Driven Shaft 88 Rotating Member 106 Operating Member 106c Spiral Concavo-convex part 112 Rolling element 114 Operation pin

Claims (2)

[Claims] 1. A driver main body having a driver bit that is rotationally driven, a driver bit drive shaft provided on the driver main body, and a screw for mounting and mounting a screw on a connecting band on the axis of the driver bit. A supply means, a nose member provided with a chuck means for holding a screw on the axis of the driver bit, a nose member supporting the nose member so as to be relatively slidable along the axis of the driver bit, and with respect to the driver body. A slide member that is relatively slidably supported, and a driving force from the driver bit drive shaft that obtains a driving force from the nose member to the innermost side of the driver body from the most projecting position that projects the nose member most outwardly from the driver body. Driving force transmission between the nose member moving means for slidingly moving to the retracted position moved toward and the nose member moving means and the driver bit drive shaft. A clutch mechanism for engaging and disengaging is provided, and the engaging operation of the clutch mechanism causes a retracting operation by the nose member moving means, whereby the first stage slide movement from the most protruding position of the nose member is performed. In the automatic screw tightener, the nose member and the slide member are subsequently slid to the retracted position in the second step and the clutch mechanism is disengaged when the retracted position is reached; The clutch mechanism is operatively connected to the nose member moving means and operates a driven shaft for operating the nose member moving means by rotation, an operating position for rotationally coupling the driven shaft to a driver bit drive shaft, and rotation transmission of both shafts. An operating member movable between an inoperative position to be separated and the nose member cooperates with each other to reach the retracted position of the nose member. In response to the operation of moving the operating member to the inoperative position, and a second response means for moving the operating member from the inoperative position to the operating position in response to the rotational start of the driver bit drive shaft. A clutch mechanism for an automatic screw tightener, comprising: a response means and a response means. 2. The second response means is formed on a rotating member which rotates integrally with a driver bit drive shaft, a claw member pivotally supported on the rotating member, and an outer periphery of the operating member, and The clutch mechanism according to claim 1, comprising a claw member and a spiral concave-convex portion that can be selectively engaged.