JP2011200978A - Automatic screw tightening machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress run-out at a distal end of a screw when screwing the screw, in an automatic screw tightening machine.SOLUTION: This automatic screw tightening machine includes a driver bit 20 engaged to a head part of the screw 18 to screw a screw part 18A of the screw 18 into an object, and rotates the driver bit 20 and moves the driver bit 20 in a direction attachable/detachable to/from the object. The head part of the screw 18 is brought into contact with a circular-arc groove, an intermediate part of the screw part 18A is brought into contact with a feeding claw, and a distal end side of the screw part 18A is inserted into a guide groove 78 of a slide guide 76, to prevent run-out on the distal end side of the screw part 18A.

Description

  The present invention relates to an automatic screw tightening machine provided with a screw linear movement holding mechanism for holding the straightness of a screw when the screw is screwed into an object.

  Various automatic screwing machines capable of automatically screwing an object into an object have been proposed (see, for example, Patent Documents 1 to 3).

Japanese Patent Laid-Open No. 63-2297. Japanese Patent Laid-Open No. 61-6058.

  However, in the apparatus disclosed in Patent Document 1, a screw is placed in a pilot hole of an object, and then the screw head is fitted with a spring arranged on a driver bit, and the screw is screwed in. It is not possible to screw a screw into an object that does not exist.

In the device disclosed in Patent Document 2, when there is a relative misalignment between the screw and the screw hole, the screw is automatically aligned, and when the screw hole is not formed in the object, I can not cope.
When screwing a screw vertically into an object, it is necessary to prevent the tip of the screw from shaking, but the above-described conventional technique cannot be applied to an object in which a pilot hole is not formed.

  The present invention has been made in consideration of the above facts, and an object thereof is to provide an automatic screw tightening machine that can suppress the deflection of the screw tip when the screw is screwed in with a simple configuration.

  The automatic screw tightening machine according to claim 1, further comprising a driver bit that engages with a screw head to screw a screw portion of the screw into an object, and rotates the driver bit and contacts and separates from the object. A screw tightening machine main body that moves in a moving direction; a loading unit that includes a waiting unit that is loaded with the screw and waits for the screw at a position facing the driver bit; and a screw that is disposed in the standby unit. First head side holding means provided on the first direction side of the axial direction intersecting with the axial direction of the head so as to be able to contact the head, and the screw loaded in the standby unit A second head-side holding means provided on the second direction side opposite to the first direction side of the screw portion so as to be able to contact the screw side portion of the longitudinal intermediate portion of the screw portion; The tip side of the screw part of the screw arranged in the part is inserted And the movement of the front end side of the screw portion toward the first direction side is prevented by the inner peripheral wall of the groove when the front end side of the screw portion is inserted into the groove. A tip-side holding means that crosses the direction and the second direction and prevents movement in an axial direction that intersects the axial direction of the screw portion, and is disposed in the standby portion. The screws come into contact with the grooves of the first head-side holding means, the second head-side holding means, and the tip-side holding means, thereby causing a vibration in a direction crossing the axial direction of the screw portion tip side. Be blocked.

Next, the operation of the automatic screw fastening machine according to claim 1 will be described.
In the automatic screw tightening machine according to the first aspect of the present invention, as a preparation, a screw is arranged in the standby section of the loading section.

The screws arranged in the standby unit are supported as follows.
In the automatic screw tightening machine according to claim 1, the first head side holding means is provided on the first direction side of the head of the screw disposed in the standby portion so as to be able to contact the head. When the screw head contacts the first head-side holding means, the screw arranged in the standby portion is prevented from moving in the first direction.
Further, since the second head side holding means is provided on the second direction side of the screw loaded in the standby portion so as to be able to contact the screw side portion of the middle portion in the longitudinal direction of the screw portion, When the middle portion in the longitudinal direction comes into contact with the second head-side holding means, in the screw disposed in the standby portion, the movement of the portion in contact with the second head-side holding means to the second direction side is Be blocked.

Here, the screw loaded in the standby portion is prevented from moving in the first direction when the head contacts the first head-side holding means, and the middle portion in the longitudinal direction of the screw portion is the second head. Since the contact portion is prevented from moving in the second direction by contacting the side holding means, the screw is prevented from tilting and the tip end side of the threaded portion swinging in the second direction.
However, there is no member that prevents the screw from moving on the second direction side of the head and the second direction side of the intermediate portion of the screw portion (the portion facing the second head side holding means). When the external force acts on the screw, the screw may be inclined and the tip side of the threaded portion may swing toward the first direction (when there is no tip side holding means).

In the automatic screw tightening machine according to claim 1, even if the tip end side of the screw is about to swing in the first direction by inserting the tip end side of the screw arranged in the standby portion into the groove of the tip side holding means, the tip end of the screw Since the side is in contact with the inner peripheral wall of the groove, the deflection of the tip end side of the screw toward the first direction is prevented.
Furthermore, even if the distal end side of the screw disposed in the standby portion swings in a direction intersecting the first direction, the second direction, and the axial direction of the screw, the distal end side of the screw is Since it contacts the inner peripheral wall of the groove, the tip end side of the screw is prevented from swinging in the direction intersecting the two directions of the first direction and the second direction and the axial direction of the screw.

Thus, in the automatic screw tightening machine according to the first aspect of the present invention, the front end side holding means suppresses the shake in the direction which cannot be suppressed by the first head side holding means and the second head side holding means on the front end side of the screw. Therefore, vibrations in all directions on the front end side of the screw can be suppressed.
In the automatic screw tightening machine according to claim 1 configured as described above, since the deflection of the screw tip side can be suppressed until the screw tip portion is screwed into the object, the tip of the driver bit is attached to the above-mentioned screw bit. The screw can be screwed into the object without being inclined by engaging with the head of the screw held in this manner and moving the screw in a direction approaching the object while rotating.

  According to a second aspect of the present invention, in the automatic screw tightening machine according to the first aspect, the loading portion includes a band-shaped member in which the screw portions of the plurality of screws are locked. A screw holding body is mounted, and the second head side holding means is a feed claw that is movable in the first direction side and the second direction side, and is fixed to the band-shaped member. Is sent to the standby portion by the feed claw moved to the first direction side, and the groove is opened toward the second direction side.

Next, the operation of the automatic screw fastening machine according to claim 2 will be described.
In the automatic screw tightening machine according to the second aspect, a screw holding body configured to include a band-like member in which a plurality of screw thread portions are locked can be attached to the loading portion.
The screw locked to the band-shaped member can be sent to the standby portion by a feed claw (second head side holding means) that is moved in the first direction.
The feed claw can move the second screw to the first direction side by moving the leading screw to the first direction side and then moving to the second direction side. Therefore, by repeating the movement of the feeding claw in the first direction and the movement in the second direction, a plurality of screws can be sequentially sent to the standby unit.
Further, in the automatic screw tightening machine according to claim 2, since the groove of the tip side holding means is opened toward the second direction side, the screw is fed to the first direction side, that is, the standby side by the feed claws. Thus, the threaded portion can be inserted as it is into the groove. Therefore, there is no need to move or change the direction of the tip side holding means when inserting the threaded portion into the groove.

  According to a third aspect of the present invention, in the automatic screw tightening machine according to the first or second aspect, the support means for supporting the tip side holding means movably in the first direction side and the second direction side. And an elastic member that urges the tip side holding means in the second direction side, and is formed in the tip side holding means, is inclined with respect to the moving direction of the tip side holding means, and the head contacts And the tip side holding means resists the biasing force of the elastic member when the head of the screw moved by the driver bit comes into contact with the inclined surface. The head is moved in the first direction to allow the head to move.

Next, the operation of the automatic screw fastening machine according to claim 3 will be described.
In the automatic screw tightening machine according to claim 3, when a screw having a threaded portion in the groove is moved while being rotated by a driver bit, and the head of the screw comes into contact with the inclined surface of the tip side holding means, A force in a direction against the urging force of the elastic member acts on the side holding means, and the tip side holding means moves in a direction against the urging force of the elastic member as the head slides on the inclined surface.
For this reason, the groove escapes in a direction away from the screw, and movement of the head having a diameter larger than that of the screw portion is allowed.

  According to a fourth aspect of the present invention, in the automatic screw tightening machine according to the third aspect, the support means is configured as a separate body from the mounting portion, and is fixed to the mounting portion using a fixing means. .

Next, the operation of the automatic screw fastening machine according to claim 4 will be described.
In the automatic screw tightening machine according to claim 4, the support means separated from the mounting part is configured to be detachably fixed to the mounting part using the fixing means. On the other hand, the support means formed as a separate part can be easily fixed to the mounting portion.

  According to a fifth aspect of the present invention, in the automatic screw tightening machine according to any one of the first to fourth aspects, the groove has a circular arc shape when viewed from the axial direction of the screw. The screw side portion on the tip side of the screw portion comes into contact with the groove bottom and the groove side walls on both sides, thereby preventing the vibration on the tip side of the screw portion.

Next, the operation of the automatic screw fastening machine according to claim 5 will be described.
In the automatic screw tightening machine according to claim 5, when the threaded portion is inserted into the groove, for example, when the threaded portion is about to swing in the first direction side, the threaded side portion of the threaded portion has an arc shape of the groove. When the threaded portion comes into contact with the groove bottom and the threaded portion tries to swing in a direction intersecting the two directions of the first direction and the axial direction of the screw, the threaded side of the threaded portion is the side wall of the groove. To prevent the thread from swinging.

  According to a sixth aspect of the present invention, in the automatic screw tightening machine according to the second aspect of the present invention, the head engaged with the tip of the driver bit does not interfere with the feed claw in the screwing process of the screw. The feeding claw is temporarily retracted from the passage route of the head.

Next, the operation of the automatic screw fastening machine according to claim 6 will be described.
In the automatic screw tightening machine according to claim 6, since the feed claw is temporarily retracted from the passage of the head during the screwing and moving process of the screw, the head engaged with the tip of the driver bit is the feed claw. The screw can be screwed in smoothly.

  As described above, according to the automatic screw tightening machine of the first aspect, it is possible to suppress the deflection of the tip of the screw when the screw is screwed in with a simple configuration, and to the object without tilting the screw. Can be screwed in.

  According to the automatic screw tightening machine of the second aspect, the screw can be inserted to the depth of the groove of the tip side holding means only by sending the screw toward the standby part.

  According to the automatic screw tightening machine of the third aspect, the head of the screw can be allowed to move with a simple configuration.

  According to the automatic screw tightening machine of the fourth aspect, the supporting means formed as a separate part with respect to the mounting portion can be easily fixed to the mounting portion. In addition, the supporting means can be provided in the mounting part and the tip side holding means of the present invention can be provided without making a significant design change such as a shape change with respect to the existing mounting part.

  According to the automatic screw tightening machine of the fifth aspect of the present invention, it is possible to reliably prevent the three-way vibration on the tip side of the screw by bringing the tip side of the screw portion into contact with the groove bottom and both side walls of the groove. it can.

  According to the automatic screw tightening machine of the sixth aspect, the screw can be screwed smoothly.

It is a right view which shows the substantially whole automatic screw fastening machine which concerns on embodiment of this invention. It is a front view of the principal part of an automatic screw fastening machine. It is a longitudinal cross-sectional view of the principal part of an automatic screwing machine. It is a perspective view of the principal part of an automatic screw fastening machine. (A) is a plan view (top view) around the loading unit, and (B) is a longitudinal sectional view in the vicinity of the loading unit. (A) is a horizontal sectional view around the loading unit, (B) is a longitudinal sectional view near the loading unit, and (C) is a front view around the loading unit. (A) is a plan view (top view) of the tip holding device, and (B) is a longitudinal sectional view of the tip holding device. (A) is the top view (top view) of the front-end | tip holding device which looked at the state at the time of a head passing from the upper side, (B) is a longitudinal cross-sectional view of the front-end | tip holding device shown to FIG. 8 (A). . It is a top view (top view) of a slide guide according to another embodiment.

An automatic screw fastening machine 10 according to an embodiment of the present invention will be described with reference to FIGS.
First, the correspondence between the direction of the present invention and the direction used in the embodiment will be described.
The “axial direction of the screw head disposed in the standby portion” of the present invention is “Z-axis direction (Z + and Z− direction)” in the embodiment.
The “first direction” of the present invention is the “X-direction” in the present embodiment.
The “second direction” of the present invention is the “X + direction” in the present embodiment.
In the present embodiment, “the crossing axial direction” of the “axial direction intersecting the first direction and the second direction and intersecting the axial direction of the thread portion” of the present invention is “ Y-axis direction (Y + and Y− direction) ”.
Further, the “screw axial direction” and the “screw axial direction” of the present invention are both “Z-axis directions (Z +, Z− directions)” in the present embodiment.

  As shown in FIGS. 1 and 2, the automatic screw fastening machine 10 of the present embodiment includes a main body 12 with a built-in motor (not shown), and is provided on the lower end side (Z-side in FIG. 1) of the main body 12. The head 16 for holding and transporting the screw continuous binding body (also called a roll screw or roll screw) 14 and the screw 18 at the head (arrow X-direction side) of the screw continuous binding body 14 supported by the head 16 are screwed into the object 50. For this purpose, a screwdriver screw 20 for screwing that can be driven and rotated by an electric motor, a steady stopper 22 that suppresses shaking of the screw continuous binding body 14, a screw tip holding device 24, and the like are provided.

  As shown in FIG. 2, the screw continuous binding body 14 temporarily holds a number of screws 18 oriented in a direction perpendicular to the tape longitudinal direction at a fixed interval in the tape longitudinal direction on a synthetic resin connecting band 26. For example, it is spirally wound and accommodated in a case (not shown), and is pulled out from the case and supported at the head 16 by the head 16.

As shown in FIGS. 2 and 3, the head 16 has a base 28 for loading and holding the screw continuous binding body 14.
As shown in FIG. 2, the base 28 is provided with a steady rest 22 including a pressing member 29 that presses the screw continuous binding body 14 against the base 28 so that the screw continuous binding body 14 does not swing. The pressing member 29 is supported so as to be swingable about the pin 31 of the base 28, and is urged by a spring 33 so as to lightly press the screw continuous body 14 against the base 28. 14 swings are suppressed.

  As shown in FIGS. 2 and 3, the conical inclined surface 18 </ b> Ba of the head portion 18 </ b> B of the screw 18 is in contact with the corner portion (extending in the X-axis direction) on the Y− direction side on the upper side of the base 28. A chamfer 32 is formed.

As shown in FIGS. 2 to 4, a protrusion 34 that protrudes from the base 28 toward the Y-direction side is formed on the side surface of the base 28 on the Y-direction side in the X-direction side.
As shown in FIG. 5, the corner portion formed by the side surface on the Y− direction side of the base 28 and the side surface on the X + direction side of the protrusion 34 has a radius R0 of the head 18B as viewed along the Z axis. A circular arc groove 36 extending in the vertical direction (Z-axis direction) having a slightly larger radius R1 is formed.

The arc groove 36 has a circumference that is more than 1/4 circle as viewed along the Z axis so that at least the end of the head 18B on the X-direction side and the end of the head 18B on the Y + direction side abut. The direction length is long. The X-direction side of the circular arc groove 36 corresponds to the first head side holding means of the present invention.
As shown in FIG. 5A, when the base 28 is viewed from the Z + side, the chamfering start line 32A of the chamfer 32 coincides with the tangent of the arc curve of the arc groove 36.

As shown in FIGS. 4 and 5, a notch 38 is formed in the vertical middle portion of the protrusion 34, and a lever 40 extending substantially along the X axis is disposed inside the notch 38. . Note that one end of the lever 40 protrudes toward the X + side of the protrusion 34.
When viewed from the Z + side, an arc-shaped recess 42 is formed on one end side (X + side) of the lever 40 on the base side (Y + direction side).
As shown in FIG. 5A, the radius of curvature R2 of the recess 42 is slightly larger than the radius of curvature R0 of the head 18B of the screw 18 so as not to interfere with the head 18B that moves when the screw is screwed. Has been.

The lever 40 is supported so as to be swingable in a horizontal plane around a pin 44 penetrating the intermediate portion in the longitudinal direction of the lever 40. As shown in FIG. 5A and FIG. It is biased in the A direction (counterclockwise direction when viewed from the Z + side). The pin 44 is supported by the protrusion 34.
Normally, the lever 40 is arranged so that the center of curvature of the recess 42 coincides with the axis of the driver bit 20 (not shown in FIG. 5 (A), FIG. 6). Even when a gap is formed between the screw portion 18A and the concave portion 42 and the screw 18 moves downward (Z-direction) and the head portion 18B corresponds to the concave portion 42, the head portion 18B and the concave portion 42 A slight gap is formed between them, and the lever 40 does not interfere with the movement of the head 18B when the screw is screwed.
The diameter of the driver bit 20 of the present embodiment is smaller than the head 18B of the screw 18.

As shown in FIG. 5A, the lever 40 is formed with a tapered surface 40A on the side facing the base 28 and on one end side (X + side) of the recess 42.
The tapered surface 40A is located on the X-direction side of the screw portion 18A of the second screw 18. Therefore, when the screw 18 is moved to the X-direction side, the screw portion 18A slides on the tapered surface 40A inclined with respect to the moving direction (X-axis direction) of the screw portion 18A, and the lever 40 is not shown. It is rotated in the direction opposite to the arrow A direction (clockwise as viewed from the Z + side) against the biasing force of the spring.

When the threaded portion 18A passes through the tapered surface 40A to the X− side and corresponds to the concave portion 42, the lever 40 is rotated in the direction of arrow A (counterclockwise as viewed from the Z + side) by the biasing force of the spring, and the initial position Returned to.
When the head side of the screw 18 arranged between the concave portion 42 of the lever 40 and the base 28 tends to swing greatly in the Y-direction, the screw portion 18A comes into contact with the concave portion 42 of the lever 40. In the portion corresponding to, a large touch to the Y-direction side is suppressed.

  As shown in FIGS. 2 to 4, the projection 34 is formed with a slit-like through hole 45 penetrating along the X axis. The through hole 45 is formed in a rectangular cross section so that the connection band 26 can be inserted. The cross-sectional dimension of the through hole 45 is formed to be slightly larger than the width and thickness of the connection band 26, and serves to guide the movement of the connection band 26.

As shown in FIGS. 1 and 2, the head 16 protrudes from the main body 12 so as to advance and retreat, and is biased in the extension direction (Z-direction) by a spring (not shown) built in the main body 12. 46 is provided at the tip.
When the screw 18 is screwed, the pair of shafts 46 slide to the main body 12 side by moving the main body 12 in the direction of the target object 50 (Z-direction) with the lower end of the head 16 facing the target object 50. The driver bit 20 advances toward the object 50 together with the main body 12 and engages with the head 18B of the screw 18 on the top (X-side) of the screw continuous binding body 14 so that the head screw 18 faces the object 50. The top screw 18 can be screwed into the object 50.

Note that the movement of the main body 12 (Z-axis direction) is performed by an actuator 53 as shown in FIG. The actuator 53 can raise a drive mechanism including a cylinder driven by air pressure or hydraulic pressure, a motor, and a feed screw, but may have other configurations.
Then, in conjunction with the movement of the main body 12, the screw continuous binding body 14 is connected to the pitch X in the direction of the arrow X-perpendicular to the screwing direction by the screw continuous binding body feeding mechanism 52 provided in the head 16, which will be described in detail below. The distance between the screws 18 temporarily held in the band 26) is sent.

(Screw continuous feed mechanism)
As shown in FIG. 1, the screw continuous body feed mechanism 52 is provided at the tip of an arm 56 integral with the main body 12, a link mechanism (not shown) built in the base 28, a feed claw 54 driven by the link mechanism. It comprises an actuating member 58 for actuating the link mechanism.

  When the main body 12 is pushed closer to the object 50 when the screw 18 is screwed in (Z-direction), the operation member 58 moves forward to operate the link mechanism, so that the feed claw 54 contacts the second screw 18. So that the feed pawl 54 passes through the second screw 18 to the X + direction side and to the side of the second screw 18 on the X + direction side. After being positioned, it protrudes from the base 28 and stops (indicated by a two-dot chain line in FIG. 4).

  When the main body 12 further approaches the object 50 and the driver bit 20 comes into contact with the head 18B of the screw 18, the motor is rotated to start the rotation of the driver bit 20, and the driver bit is placed on the head 18B of the screw 18. When the tip of 20 is engaged and the screw 18 is rotated, the screw 18 is detached from the connecting band 26 and approaches the object 50 while rotating. Since the feed claw 54 stands by on the side of the second screw 18 on the X + direction side, it does not come into contact with the head 18B of the leading screw 18.

  After the screw 18 is screwed into the object 50, the main body 12 is moved away from the object 50 (moved toward the Z + direction) to return the main body 12 to the original position. In the returning process, the actuating member 58 moves backward to return the link mechanism, so that the feed claw 54 (shown by a two-dot chain line in FIG. 4) protruding from the base 28 becomes the X + of the screw portion 18A of the next screw 18. The head 18B of the next screw 18 abuts against the side of the direction side and stops until the screw 18 moves to the X-direction side until the head 18B of the next screw 18 abuts against the arc groove 36 (see the feed claw 54 shown by the solid line in FIG. 4). ).

  In addition, this screw continuous binding body feeding mechanism 52 can use a mechanism (for example, a mechanism disclosed in Japanese Patent Publication No. 1-58029) generally used in this type of automatic screw fastening machine.

(Screw holding device)
As shown in FIG. 2, the screw tip holding device 24 is provided on the lower end side of the base 28.
As shown in FIGS. 4 and 7, the screw tip holding device 24 of the present embodiment includes a main body 60, a slide guide 76, a hexagon socket head bolt 64, a coil spring 66, and a nut 68.

  The main body 60 is viewed from above (Z + side), a mounting portion 60A extending in a direction perpendicular to the side surface of the base 28 (Y-axis direction), and a direction (X +) orthogonal to the Y-direction side end of the mounting portion 60A. And a support portion 60 </ b> B extending in the direction), and is formed in a substantially L shape as a whole.

  As shown in FIG. 2, the main body 60 is attached by bolts 59 to the side surfaces of the protrusions 70 whose mounting portions 60 </ b> A protrude from the side surfaces of the base 28. Therefore, the screw tip holding device 24 can be easily attached to and detached from the base 28.

  As shown in FIGS. 4 and 7, a protrusion 72 is formed on the X + direction side of the support portion 60B toward the base side (arrow Y + direction side). The protrusion 72 is formed with a relief groove 74 that has an arc shape when viewed from above and extends along the Z-axis. The radius of curvature of the escape groove 74 is slightly larger than the radius of curvature of the head 18B of the screw 18 (1/2 of the diameter). The center of curvature of the escape groove 74 is on an extension line of the axis of the driver bit 20. Therefore, the head 18B of the screw 18 moved downward by the driver bit 20 can move below the protrusion 72 without contacting the protrusion 72.

A block-shaped slide guide 76 is disposed below the protrusion 72.
As shown in FIG. 7A, when this slide guide 76 is viewed from above (Z + side), a guide groove 78 extending in the vertical direction (Z-axis direction) and opening to the X + side is formed on the X + side. Yes.

  Further, when the guide groove 78 is viewed from above (Z + side), the guide groove 78 has a semicircular arc shape at the groove bottom portion 78A, and the distance between the groove side walls 78B and 78C increases toward the X + side. Further, it is inclined with respect to the X axis. The Y-side groove side wall 78B is shorter than the Y + side groove side wall 78C.

The curvature radius of the groove bottom portion 78A is slightly larger than the curvature radius of the screw portion 18A of the screw 18, and the tip side (lower end side) of the screw portion 18A of the screw 18 enters the guide groove from the X + side. Thus, when the screw portion 18A hits the groove bottom portion 78A, the tip side of the screw 18 is prevented from moving in the X-direction, the Y + direction, and the Y-direction.
As an example, when the diameter of the screw portion 18A is φ4 mm (curvature radius 2 mm), the curvature radius of the groove bottom portion 78A can be set to, for example, more than 2.0 mm and 2.5 mm or less. If the curvature radius of the groove bottom portion 78A becomes too large with respect to the curvature radius of the screw portion 18A, it is impossible to suppress the deflection of the screw 18 in the Y + direction and the Y− direction.

  On the other hand, as shown in FIG. 7B, in the longitudinal section when the slide guide 76 is viewed from the Y− side, the slide guide 76 has an inclined surface 80 that is lowered toward the X + side on the X + side of the upper surface. Yes.

  As shown in FIG. 7, a hole 82 along the X axis is formed in the attachment portion 60 </ b> A of the main body 60, and a hexagon socket bolt 64 is inserted into the hole 82 from the X− side. A screw tip portion of the hexagon socket head cap screw 64 is screwed into a female screw portion formed in the slide guide 76. Further, a nut 68 is screwed into the threaded portion 64A of the hexagon socket head cap screw 64, and the nut 68 is provided on the side surface of the slide guide 76 so that the hexagon socket head cap screw 64 screwed into the slide guide 76 does not loosen. Are in strong contact.

The hexagon socket head cap screw 64 is provided with a coil spring 84 between the nut 68 and the mounting portion 60 </ b> A, and the slide guide 76 is urged in the X + direction by the coil spring 84.
For this reason, at the normal time (when the screw 18 does not enter the guide groove 78), as shown in the figure, the head portion 64B of the hexagon socket head cap screw 64 is in contact with the mounting portion 60A.

  In the normal state, the center of curvature of the groove bottom portion 78 </ b> A having the arc shape of the slide guide 76 is on the extension line of the axis of the driver bit 20. That is, at the normal time, the driver bit 20 has both the center of curvature of the groove bottom portion 78A formed into the arc shape of the slide guide 76 and the center of curvature of the arc-shaped escape groove 74 formed in the protrusion 72 of the main body 60. It is on the extension line of the axis.

(Function)
Next, the operation of the automatic screw fastening machine 10 of this embodiment will be described.
First, the screw continuous binding body 14 is mounted on the automatic screw fastening machine 10. As shown in FIG. 4, the leading end side of the connecting band 26 is passed through the through hole 45, and the leading screw 18 is disposed in the circular arc groove 36 as a standby portion.
When the screw 18 is disposed in the arc groove 36, the end on the X-direction side of the lever 40 is pushed to the Y + side, the end on the X + side of the lever 40 is moved to the Y- side, and separated from the base 28, The leading screw 18 is inserted into the circular arc groove 36 through the opened gap. After the leading screw 18 is inserted into the arc groove 36, the lever 40 is returned to its original position (see FIGS. 4 to 6).

  The state of the screw 18 inserted into the circular arc groove 36 will be described in detail. When some external force is applied to the screw 18, as shown in FIG. The X-side movement of the head 18B is prevented by contacting the X-side groove wall (first head side holding means) of the groove 36, and the Y + side of the head 18B is the groove on the Y + side of the arc groove 36. The movement of the head 18B on the Y + side is prevented by contacting the wall.

  As shown in FIG. 4, below the feed claw 54, the screw portion 18A of the screw 18 is locked to the connecting band 26. Therefore, at the position locked to the connecting band 26, the screw portion 18A is connected to the X axis. The movement in the direction and the Y-axis direction is restricted to some extent.

  As shown in FIGS. 4 and 6, in the upper screw portion 18A of the connecting band 26, the feed claw 54 (second head side holding means) is in contact with the X + side of the screw portion 18A. In the portion where the claw 54 is in contact, the movement of the screw portion 18A toward the X + side is prevented.

By the way, when some external force is applied to the screw 18, at the upper part of the screw 18, the X-side of the head 18B contacts the X-side groove wall of the arc groove 36, and the X + side of the intermediate portion of the screw portion 18A feeds. 2, the screw 18 is prevented from inclining to the left side of the drawing in FIG. 2, but the upper side of the screw 18 restricts (contacts) the screw 18 to the right side. In some cases, the screw 18 tilts to the right and the tip of the screw 18 swings to the X-side (for example, a swing of about 2 mm).
Since the connecting band 26 made of synthetic resin is elastically deformed, it is difficult to restrain the movement of the screw 18 so that the tip of the screw 18 does not swing to the X-side.

  Further, on the upper side of the screw 18, as shown in FIG. 4, the Y− side of the threaded portion 18 </ b> A is fixed to the elastically deformable connecting band 26, and the Y + side of the head 18 </ b> B is a groove on the Y + side of the arc groove 36. Since it is in contact with the wall, if the connecting band 26 is deformed by some external force, the tip of the screw 18 may swing greatly (for example, about 5 mm) to the Y + side or the Y− side.

  Even if the tip of the driver bit 20 is temporarily engaged with the head 18B of the screw 18 held in this state, if the screw tip holding device 24 is not provided, the screw 18 is connected to the driver bit 20 and the head 18B. The tip of the screw 18 swings in the X− direction, the Y + direction, and the Y− direction when some external force acts on the screw 18.

  However, in the automatic screw tightening machine 10 of the present embodiment, the distal end side of the screw 18 is inserted into the guide groove 78 of the slide guide 76 provided in the screw distal end holding device 24, and the X-direction, Y + direction, Y on the distal end side is inserted. Since the movement in the − direction is prevented, the shake in the X + direction, the X− direction, the Y + direction, and the Y− direction, that is, the horizontal direction on the tip side of the screw 18 is completely suppressed.

The operation when the screw 18 set in the arc groove 36 as the standby portion is screwed into the object 50 in this way will be described below.
(1) First, the main body 12 is lowered by an actuator 53 (not shown), but at the beginning of the lowering, the driver bit 20 is not rotated, and the driver bit 20 comes into contact with the head 18B of the screw 18 after the tip of the driver bit 20 comes into contact. Is rotated. The screw 18 is detached from the connecting band 26 when the screw 18 is rotated by engaging the driver bit 20 with the head 18B.

If the tip of the driver bit 20 engages the head 18B of the screw 18, the head 18B of the screw 18 will not swing in the horizontal direction (X-axis direction, Y-axis direction).
Naturally, since the distal end side of the screw 18 is fitted and supported in the guide groove 78 of the slide guide 76, the X + direction, the X− direction, the Y + direction, and the Y− direction on the distal end side of the screw 18, that is, the horizontal direction. The shake is suppressed. That is, the axis of the screw 18 is not inclined with respect to the axis of the driver bit 20.
Therefore, in this state, if the screw 18 whose tip deflection is suppressed is pushed by the driver bit 20 and proceeds toward the object 50, the screw 18 is screwed into the object 50 without being inclined. It will be.

(2) In the automatic screw tightening machine 10 of the present embodiment, since the concave portion 42 that allows the head 18B to escape is formed in the lever 40, the head 18B of the screw 18 does not interfere with the lever 40 and the lever 40 Passes downward (Z-side).
Further, in order to prevent the head 18B of the screw 18 from descending and interfering with the feed claw 54, the feed claw 54 is pulled into the base by the link mechanism while the screw 18 is being lowered. Therefore, the feeding claw 54 does not become an obstacle to screwing of the screw 18.

(3) Further, when the screw 18 is lowered, the head 18B of the screw 18 passes downward without contacting the protrusion 72 of the screw tip holding device 24, and thereafter, the inclined surface 18Ba of the head 18B is moved to the slide guide 76. To touch.
As the screw 18 descends in a state where the inclined surface 18Ba of the head 18B is in contact with the slide guide 76, the slide guide 76 uses the inclined surface 80 of the slide guide 76 as the inclined surface of the head 18B as shown in FIG. As the coil spring 66 is compressed and moved in the X-direction while sliding with 18Ba, the head 18B of the screw 18 finally corresponds to the wide portion of the guide groove 78. 18B passes through the guide groove 78 while sliding in the guide groove 78.
The urging force of the coil spring 66 can suppress the deflection of the tip end side of the screw 18 before the driver bit 20 is engaged, and is screwed in when the head 18B passes below the slide guide 76. A small force that does not become an obstacle is sufficient.
Therefore, although the slide guide 76 contacts the head 18B, the screw 18 is smoothly screwed.

(4) When the head 18B passes through the guide groove 78 downward, the slide guide 76 biased by the coil spring 66 is pushed in the X + direction to return to the original position.
When the head 18B comes into contact with the object 50 and the screwing is completed, the rotation of the driver bit 20 is stopped.
(5) After the screw 18 is screwed in, the actuator 12 moves the body 12 away from the object 50 (moves in the Z + direction) by the actuator 53 and returns to the original position. In the process of returning the main body 12 to the original position, the feeding claw 54 sends the next screw 18 to the X-side and enters a standby state.

As described above, in the automatic screw tightening machine 10 of this embodiment, the use of the screw tip holding device 24 can completely suppress the deflection of the tip of the screw 18, and the screw 18 is attached to the object 50. Can be screwed in without tilting.
In the screw tip holding device 24, the guide groove 78 that holds the screw portion 18 </ b> A of the screw 18 is opened toward the side opposite to the feeding direction of the screw 18, so that the screw 18 is only fed by the screw continuous binding feed mechanism 52. Thus, the leading end side of the screw portion 18A can be inserted into the guide groove 78, and the leading end side of the screw 18 can be prevented from shaking.
Therefore, even if the screw 18 is long (for example, 80 mm or more), the deflection on the tip side of the screw 18 can be reliably suppressed.

Further, the screw tip holding device 24 has a simple configuration in which the slide guide 76 is biased by the coil spring 66 without using a complicated mechanism such as an actuator, and the head 18B of the screw 18 being screwed in can be moved. It can be escaped and screwing can be performed smoothly.
In addition, since the screw | thread front-end | tip holding | maintenance apparatus 24 of this embodiment is comprised as another component with respect to the base 28, it can also be mounted | worn with the existing automatic screw fastening machine.

[Other Embodiments]
The shape of the guide groove 78 of the slide guide 76 is not limited to the shape shown in FIG. 7A, and may be another shape such as a substantially V shape as shown in FIG. Although there are two contact points between the groove wall of the V-shaped groove and the screw portion 18A, the deflection in the X-direction, Y + direction, and Y-direction on the tip side of the screw 18 is the same as the groove shape shown in FIG. Can be suppressed.

10 Automatic screw fastening machine 12 Body (screw fastening machine body)
14 Screw chain (screw holder)
18 screw 18A screw part 18B head 20 driver bit 26 connecting band (band-shaped member)
28 base (loading section)
36 Arc groove (standby section, first head side holding means)
50 Object 53 Actuator 54 Feeding claw (second head side holding means)
59 bolts (fixing means)
60 Main body (support means)
64 bolts (support means)
66 Coil spring (elastic member)
74 Groove 76 Slide guide (tip side holding means)
78 Guide groove (groove)
78A groove bottom (inner wall, groove bottom)
78B Groove side wall (inner wall)
78C Groove side wall (inner wall)
80 inclined surface

Claims (6)

A screw tightening machine main body that includes a screwdriver bit that engages with a screw head and screwes the screw portion of the screw into an object, and that rotates the screwdriver bit and moves in a direction to contact and separate from the object;
A loading unit provided with a standby unit for loading the screw and waiting the screw at a position facing the driver bit;
First head-side holding means provided on the first direction side of the axial direction intersecting the axial direction of the head of the screw disposed in the standby portion so as to be able to contact the head. ,
A second side of the screw loaded in the standby portion is provided on the second direction side opposite to the first direction side so as to be in contact with the screw side portion of the middle portion in the longitudinal direction of the screw portion. A head-side holding means;
The screw is disposed in the standby portion, and includes a groove into which the tip side of the screw portion is inserted, and when the tip side of the screw portion is inserted into the groove, the tip of the screw portion is inserted by the inner peripheral wall of the groove. And the movement in the axial direction that intersects the first direction and the second direction and intersects the axial direction of the screw portion. A tip-side holding means,
The screw arranged in the standby portion intersects the axial direction on the tip side of the screw portion by contacting the first head side holding means, the second head side holding means, and the tip side holding means. Automatic screw tightening machine that prevents run-out in the direction of rotation. A screw holding body configured to include a band-like member in which the screw portions of the plurality of screws are locked is attached to the loading portion,
The second head side holding means is a feed claw that is movable in the first direction side and the second direction side,
The screw locked to the band-shaped member is sent to the standby portion by the feed claw moved to the first direction side,
The groove is opened toward the second direction side.
The automatic screw fastening machine according to claim 1. Support means for movably supporting the tip side holding means in the first direction side and the second direction side;
An elastic member for urging the tip side holding means toward the second direction;
An inclined surface that is formed on the distal end side holding means, is inclined with respect to the moving direction of the distal end side holding means, and the head contacts;
With
When the head portion of the screw moved by the driver bit contacts the inclined surface, the tip side holding means moves toward the first direction against the urging force of the elastic member. The automatic screw tightening machine according to claim 1 or 2, wherein the head is allowed to move.   The automatic screw tightening machine according to claim 3, wherein the support means is configured as a separate body from the mounting portion, and is fixed to the mounting portion using a fixing means.   The groove has a groove bottom having an arc shape when viewed from the axial direction of the screw, and the screw side portion on the tip side of the screw portion comes into contact with the groove bottom and the groove side walls on both sides. The automatic screw tightening machine according to any one of claims 1 to 4, wherein a vibration on a tip side of the portion is prevented.   The feed claw is temporarily retracted from a passage path of the head so that the head engaged with the tip of the driver bit does not interfere with the feed claw in the screwing process of the screw. 2. Automatic screw fastening machine according to 2.

Images