JPH11129182A - Work reversing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably position works even when outer peripheral surfaces of the works are different in their outer peripheral shapes from each other at non-cut surfaces by reversing the works via a jig pin without directly grabbing the works so that the central position of holes of the works are not displaced before and after reversing. SOLUTION: The lower side shaft part of a collar part Sa of a jig pin S is vertically grabbed by grabbing claws 9Ba, 9Bb of a second gripper element 8B, grabbing claws 9Aa, 9Ab of a first gripper element 8A are opened, a work W is allowed to stand by at an inserting position by fingers R, R of a pick and place. The work W is inserted into the collar part Sa of the jig pin S, and the grabbing claws 9Aa, 9Ab of the first gripper element 8A grab the upper side shaft part of the jig pin S. The gripper element is vertically reversed, the work W is reversed, the second gripper element 8B previously placed on the lower side comes to the upper side, and therefore, the grabbing claws 9Ba, 9Bb is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for reversing a workpiece which are effective when operations such as machining and assembling are performed on upper and lower surfaces of parts and the like. More specifically, the present invention relates to a method and an apparatus for reversing a work in which at least one hole penetrating between two surfaces is formed.

[0002]

2. Description of the Related Art Conventionally, various types of work reversing devices are known. For example, in the case of Japanese Utility Model Laid-Open No. 4-79089, as shown in FIGS.
The work 102 on the object 01 is inverted at that position. In this reversing device, a housing 105 is moved up and down by a hydraulic cylinder device 106 along a guide 104 provided on a machine frame 103. The housing 105 has a pair of gripping claws 107 and 10 for gripping the work.
A revolving body 108 provided at the front end so as to be able to open and close 7 is rotatably supported. This pair of gripping claws 107, 107
Is provided so as to be openable and closable by forward and backward movement of a piston 109 of a fluid pressure cylinder device at a tip portion of the revolving body 108. The revolving unit 108 is provided with a pinion 111 between shaft bearings, and a rack 114 of a piston 113 of an air cylinder 112 provided so as to be orthogonal to the axis of the revolving unit 108 is engaged with the pinion 111 so that a cylinder is formed. 1
The revolving unit 108 is rotated 180 ° by the piston 113 which is moved by the pressure fluid supplied alternately to the chambers on both sides of the revolving unit 12. Therefore, the work 102 is inverted at the same position on the table 101 when the grip claws 107, 107 grip the work 102 and move upward by 180 ° inversion.

[0003]

The gripping claw (chuck) of the prior art directly grips the outside of a work. For example, the work has a non-linear outer peripheral surface such as a die-cast molded product or a cast product. In the case of a non-cutting surface, there is a problem that the position where the workpiece is gripped is not constant, so that the workpiece position is not uniform with respect to the gripping center, and the rotational positioning accuracy of the inverted workpiece before the inversion is poor. Was.

In order to cope with various kinds of works,
It is necessary to form and prepare a large number of gripping claws of the gripping means so as to fit each work, and these must be managed and stored. there were. Each time the workpiece to be gripped is changed, the gripping claw must be replaced with a suitable one, which requires a man-hour for replacement, which lowers the production efficiency. Further, in order to reverse the gripped workpiece and grip the next workpiece, it is necessary to return the gripping claw of the gripping unit to the original position before the reversal, so that there is a problem that the reversal tact of the workpiece becomes longer and the production efficiency is reduced. .

[0005] The present invention has been made in view of such problems of the prior art.
In the case where the outer peripheral surface of the work is a non-cut surface such as a die cast or a casting, it is easy to grip the work with the work having the upper and lower through-holes, and a single work can be performed even for various kinds of work. It is an object of the present invention to provide a reversing method and device capable of being gripped by gripping claws (chuck). Another object of the present invention is to provide a reversing device for a workpiece that can be continuously gripped without returning a gripping claw to an original position in order to grip a next workpiece.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is a method for reversing a work having at least one hole penetrating between two surfaces, wherein the gripping center is concentric. One end of a jig pin that can be inserted into a hole of the work by using a reversing device in which two sets of grippers that can be opened and closed separately can be integrally turned around a center of the thickness of the work and an axis perpendicular to the gripping center. After gripping the part with one of the two sets of grippers, inserting the hole of the work into the jig pin, and gripping the other end of the jig pin protruding from the work with the other gripper, the axis of the jig pin is removed. By inverting the gripper and opening the gripper previously gripped to take out the work, the center position of the hole in the work is inverted via the jig pin without directly gripping the work so as not to shift before and after the inversion.

[0007] In addition, at least one penetrating between the two surfaces.
A jig pin that can be inserted into the hole of the work and that is longer than the distance between the front and back surfaces, and that can independently hold both ends of the jig pin and that can be independently opened and closed. A pair of grippers provided in parallel with two sets of grippers openable and closable by a drive mechanism with their respective grip centers being the same, and a rotation drive capable of reversing and positioning by rotating the axis of the jig pin gripped by the grippers. And a control means for operating the gripping means for independently opening and closing the two sets of grippers and the turning drive means for turning and positioning the jigs, one end of which is held by one of the grippers. Insert the hole of the work into the pin, grip the other end of the jig pin protruding from the work with the other gripper, and turn the jig pin to the position where the axis of the jig pin is reversed by the turning drive means. In which turning over the work.

A work is inserted into a jig pin gripped by one gripper, and a portion of the jig pin protruding from the work is gripped by the other gripper, and the gripping means is reversed. By inserting the holes of the work into the jig pins, the position of the work hole after the reversal is stabilized and the same gripping claws can cope with various kinds of works.

Also, a fixed protrusion provided on one of the grippers of the pair of gripping means, to which the side surface of the work can abut, and the work piece being held on the same side of the work with respect to the fixed protrusion with respect to the work holding center. A movable projection that is provided on the side surface and is capable of moving forward and backward to press and rotate the work is provided, and both ends of the jig pin inserted into the hole of the work are gripped by a pair of gripping means, and then moved. The projection is advanced, the work is rotated about the jig pin, and is brought into contact with the fixed projection, thereby performing rotation positioning with respect to the hole center of the inverted work. After or during the reversal of the work, the work is rotated and positioned with respect to the jig pin. For this reason, even a workpiece having a complicated shape can be positioned in a fixed state.

[0010] Further, a pair of gripping means is provided on both sides of the gripping center of the work in parallel in a direction perpendicular to the gripping center, and the retreating end can be positioned at an arbitrary position to press the same side surface of the work. Two movable projections which can move forward and backward,
When one of the two moving projections is positioned at the retreating end, the other is advanced or when the other is positioned at the retreating end, the one is advanced. A control means for controlling the operation and related operations is provided, and after holding both ends of the jig pin inserted into the hole of the work by a pair of gripping means, one of the moving projections is set at the retracted end position. Positioning, moving the other moving projection forward, rotating the work around the jig pin, and pressing the work against the moving projection positioned backwards to rotate the work relative to the hole center of the inverted work. That is what we do. After taking out the workpiece by alternately using one of the two moving projections as the positioning projection, the gripping means is reversed by exchanging the positioning projection and the work pressing projection. The next work can be accepted as it is, and work efficiency is improved. The work can be always rotated and positioned in a constant state.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIG. 1 showing a side view, FIG. 2 showing a plan view, FIG. 3 showing a reversing drive mechanism of turning drive means, and FIG.

A cylinder having a pair of parallel operating portions of turning drive means which is operated by pressure fluid supplied alternately from pressure fluid supply pipes 6A and 6B provided on the same side surface is provided on a stand portion 1a of the machine base 1. The body 2 is fixed. This cylinder body 2 is provided with two cylinders 2A and 2B,
Linear pistons 4A and 4B are fitted to the cylinders 2A and 2B so as to be able to reciprocate, and racks 4Aa and 4Ba are engraved on the linear pistons 4A and 4B so as to face each other. A pinion shaft 3 is supported on the cylinder body 2 between the linear motion pistons 4A and 4B so that one end protrudes perpendicularly to the operating axis of the linear motion pistons 4A and 4B. The pinion shaft 3 has a rack 4Aa. , 4Ba are carved with pinions 3a.

Therefore, by supplying the pressure fluid from the pressure fluid supply pipe 6A and setting the pressure fluid supply pipe 6B on the discharge side, the linear motion piston 4A moves forward, the pinion 3a rotates, and the communication passages at the ends of the cylinders 2A, 2B. The fluid in the cylinder 2A is sent to the cylinder 2B from 2a, and the direct acting piston 4B is moved in the opposite direction (FIG. 3). Linear piston 4A, 4
Permanent magnets 5A and 5B are attached to B, respectively, and the magnetic sensors 5C and 5D detect the positions thereof so that the moving end of the piston can be confirmed. Of course, the cylinder body 2 is made of a non-magnetic material, for example, aluminum.

Conversely, the pressure fluid is supplied from the pressure fluid supply pipe 6B, and by moving the pressure fluid supply pipe 6A to the discharge side, the moving directions of the linear motion pistons 4A and 4B are reversed.
By this repetitive operation, the pinion shaft 3 is rotated forward / reversely via the pinion 3a, and the revolving unit 7 described later is inverted by 180 °. The protruding end of the pinion shaft 3 has a flange 3
b is formed, and the revolving unit 7 is formed on its end surface such that the work gripping center of the first and second gripper bodies described later is vertical.
Are fastened by bolts. The revolving unit 7 has a stepped portion 7a at an upper and lower symmetrical position with respect to a revolving axis of the pinion shaft 3 (hereinafter, referred to as a revolving center) at intervals above and below a reversing work which can be gripped. , 7b, and grippers 8A, 8B having a pair of gripping claws respectively attached to a pair of gripping means.

The grippers 8A and 8B have the same mechanism. Accordingly, the same parts of the upper and lower gripper bodies (hereinafter referred to as first and second gripper bodies) are identified by adding the same numbers to A and B, and the first gripper body 8A at the upper position in FIG. explain.

The first gripper body 8A has a pair of gripping claws 9A.
a and 9Ab are located at the upper position of the turning center (FIG. 1) and are spaced symmetrically (FIG. 4) with respect to the turning center, and one ends of the gripping claws 9Aa and 9Ab are turned around the first gripper body 8A. Keys are attached to the oscillating shafts 11Aa and 11Ab, respectively, which are movably supported in the vertical direction (perpendicular to the center of rotation of the revolving unit 7). The other end has an arc or a V-plane formed at a position where they can face each other and is formed parallel to the swing shafts 11Aa and 11Ab, and can vertically grip a jig pin S described later when the gripping claws 9Aa and 9Ab are closed. is there. And the swing shaft 11Aa, 1
1Ab has the same number of pinions 12Aa and 12A respectively.
b is engraved integrally.

A cylinder 13A is provided in the first gripper body 8A at the center between the pinions 12Aa and 12Ab and parallel to the center of rotation, and a piston 14A is fitted so as to reciprocate. Racks 16Aa and 16Ab carved on both sides of the piston rod 16A fixed to the piston 14A and projecting from the pinion-side cylinder wall are engaged with the pinions 12Aa and 12Ab, respectively. Therefore, the pressure fluid is alternately supplied to the pressure fluid supply pipes 17Aa, 17Ab in the front and rear chambers separated by the piston 14A in the cylinder 13A, so that the pair of gripping claws 9Aa, 9Ab swing by the forward and backward movement of the piston 14A. Shaft 11Aa, 1
It is opened and closed via 1Ab.

A permanent magnet 18A is attached to the piston 14A, and a magnetic sensor 19A detects the positions of the front and rear ends of the permanent magnet 18A, and opens and closes the forward and backward ends of the piston 14A, that is, the holding claws 9Aa and 9Ab. Is output. Of course, the gripper body 8A is made of nonmagnetic aluminum. A pair of gripping claws 9Aa,
A first gripper composed of 9Ab and a first gripper body 8A including a cylinder 13A and a piston 14A of the opening and closing drive mechanism, and a pair of gripping claws 9Ba and 9Bb and a first gripper including a cylinder 13B and a piston 14B of the opening and closing drive mechanism. The second gripper composed of the two gripper bodies 8B is vertically symmetrical with respect to the center of rotation of the revolving body 7 with respect to the center of revolving of the revolving body 7 as described above, and can be independently opened and closed independently of the work thickness. It is provided in. The gripping claws 9Aa and 9Ab of the first gripper and the gripping claws 9Ba and 9Ba of the second gripper,
The surfaces facing each other 9Bb serve to position the upper and lower surfaces of the work W in a direction perpendicular to the upper and lower surfaces of the work W inserted into the jig pin S.

Further, as a moving projection, a revolving body 7 is provided on a protruding portion 7c of the revolving body 7 between the first and second gripper bodies 8A and 8B.
A cylinder 21A is provided in parallel with the center of rotation of the cylinder (at right angles to the gripping axis of the gripper), and a protrusion 23A is screwed onto the tip of a piston rod 22A on the work side of a reciprocable piston (not shown) so that the position can be adjusted. ing. Then, the workpiece W in which the advancing protrusion 23A is inserted into the jig pin S
The work W can be pressed against the side surface of the work W. Further, a spring is inserted in the chamber on the protruding side of the cylinder 21A, and when the pressure fluid in the rear chamber is discharged, the piston is pushed and the protruding part 23A is set to the retreat position.

As a fixed projection, a positioning pin 24 capable of contacting the side surface of the workpiece W inserted into the jig pin S is provided on the gripping claw 9Ba of the second gripper farther from the movable projection than the workpiece gripping center. It is planted at a position parallel and eccentric from the center of rotation. Therefore, the work W inserted into the jig pin S is pressed by the advancing projection 23A and rotated about the jig pin S, and the work W is rotated at a position where the side surface of the work W contacts the positioning pin 24. Positioning is performed.

As a sensor for detecting whether or not the work W has been inserted into the jig pin S gripped by the second gripper, a light emitter 26a and a light receiver 26b each containing a light emitting diode are provided in a stand portion 1b of the machine base 1. Are provided as a pair, and the light beams cross the work W inserted into the jig pin S. Therefore, the presence / absence of insertion of the work W is detected based on the presence / absence of light reception of the light receiver 26b.
R and R are pick-and-place fingers for inserting or removing the workpiece W from the jig pin S.

Another embodiment of the rotation positioning of the work with respect to the axis of the jig pin S will be described with reference to FIG. Instead of the positioning pin 24 of the fixed projection shown in FIG.
A, piston rod 22A, protrusion 23 with adjustable access
A of the cylinder 21B,
A second moving projection composed of a piston rod 22B and an adjustable projection 23B is provided on the projection 7c in the same direction in parallel with a symmetric position on the opposite side with respect to the center of rotation of the revolving body 7.
In this case, since one of the movable projections is a fixed projection, the positions of the projections 23A and 23B are adjusted so that the rotational position of the work W is determined at the retracted end of the piston. Therefore, positioning can be performed on either side of the rotation direction of the work W.

Next, in FIG. 6 showing a control block diagram, reference numeral 31 denotes a light cutoff signal of the light receiver 26b of the photoelectric switch.
Magnetic sensor 5C, 5D of double cylinder of cylinder body 2
, A signal of the magnetic sensor 19A of the cylinder of the first gripper, and a signal of the magnetic sensor 19B of the cylinder of the second gripper, and a command that can be input to output a necessary signal. Reference numeral 32 denotes a quasi-five-port two-position switching solenoid valve for switching the supply pressure to the pressure fluid supply pipes 6A and 6B of the cylinder body 2 according to the output of the control circuit 31. Reference numeral 33 denotes a quasi five-port two-position switching solenoid valve for switching the pressure fluid to the cylinder 13A of the first gripper body 8A according to the output of the control circuit 31. 34 is the second output signal from the control circuit 31.
This is a quasi five-port two-position switching solenoid valve that switches the pressure fluid to the cylinder 13B of the gripper body 8B. Reference numeral 35 denotes a switching solenoid valve which switches on and off the pressure fluid to and from the cylinder 21A of the first moving projection according to the output of the control circuit 31. Reference numeral 36 denotes a switching solenoid valve for switching the pressure fluid into and out of the cylinder 21B of the second moving projection.

The operation of the present invention in a state where two moving projections having such a configuration are provided will be described. FIG. 6 showing a control block diagram, gripping claws 9Ba, 9Bb of the second gripper body 8B
, The lower shaft portion of the flange portion Sa of the jig pin S is vertically gripped,
FIG. 7 shows a state in which the gripping claws 9Aa and 9Ab of the first gripper body 8A are opened, and the workpiece W is on standby at the insertion position by the pick and place fingers R. FIG. FIG. 8 shows a state in which the gripping claws 9Aa and 9Ab of the first gripper body 8A are inserted and grips the upper shaft portion of the jig pin S. FIG. Upper side, gripping claws 9Ba, 9
This will be described with reference to FIG. 9 showing a state where Bb is opened and FIG. 10 showing a flow of operation.

When the work W having at least one hole is specified, a jig pin S is selected in which the diameter of the flange Sa of the jig pin S matches the hole diameter of the specified work W. The retracting ends of the first and second movable projections are aligned with the side surfaces corresponding to the rotational positioning position of the work W, and the projections 23A, 23B
Adjust the position of. The control circuit 31 outputs an initial state command. That is, light is emitted from the light emitter 26a of the photoelectric switch, and the switching solenoid valves 33 and 34 are switched so that the first gripper and the second gripper are opened.
The pressure fluid in the cylinders 21A and 21B of the moving projection is shut off, and the switching solenoid valve 32 is switched to the cylinder body 2 so that the first gripper is on the upper side and the second gripper is on the lower side. Next, a manual input is performed, and the switching electromagnetic valve 34 of the second gripper is switched by the control circuit 31 so that the lower second gripper (gripping claw 9
Ba, 9Bb) to hold the shaft portion below the flange portion Sa of the jig pin S, and the upper first gripper (gripping claws 9Aa, 9A).
b) is made to stand by in an opened state (FIG. 7).

In step S1, the work W is inserted into the jig pin S by the fingers R. In step S2, it is confirmed from the light emitter 26a of the photoelectric sensor that the light beam received by the light receiver 26b has been blocked by the work W. If NO, the work is not yet inserted, and the insertion is awaited. Steps S1 and S2 are repeated. If the signal is sent from the light receiver 26b to the control circuit 31 and the light beam is cut off by the work, and if YES, the switching solenoid valve 33 is switched by the command of the control circuit 31 in step S3, and the pressure fluid is supplied to the front chamber of the cylinder 13A of the first gripper. Feed gripping claws 9Aa, 9
The Ab is closed and the shaft above the flange Sa of the jig pin S is gripped (FIG. 8).

In step S4, it is confirmed whether or not a signal indicating that the grip has been completed has been output from the magnetic sensor 19A. In the case of NO, steps S3 and S4 are repeated until the confirmation signal is output. The signal of the electromagnetic sensor 19A is input to the control circuit 31 and Y
In the case of ES, the process proceeds to step S5, in which the switching solenoid valve 32 is switched by a command of the control circuit 31 to supply the pressure fluid to the cylinder 2A from the pressure supply pipe 6A of the cylinder body 2, and the pressure fluid supply pipe 6B is set to the discharge side to directly change the pressure fluid. The dynamic piston 4A is moved to invert the pinion shaft 3 by 180 ° via the pinion 3a.

In step S6, the magnetic sensors 5C, 5
It is determined whether the output of D has been switched and if NO, steps S5 and S6 are repeated, and the process waits until switching. When the switched signal is confirmed by the control circuit 31, the result is YES, and in step S7, the switching solenoid valve 35 is switched by the command of the control circuit 31, and the cylinder 21 of the first moving projection is switched.
A pressure fluid is sent to the rear chamber of A, the piston rod 22A is advanced, the projection 23A is brought into contact with the side surface of the work W, and the work W is rotated around the jig pin S. The work W is pressed by the protrusion 23A at a position where the work W comes into contact with the protrusion 23B serving as a child, and is reliably positioned. This step S7 can be incorporated during the reversing operation of step S6.

In step S8, the switching solenoid valve 34 is switched to reverse, and the pressure fluid is sent to the rear chamber of the cylinder 13B of the second gripper, which is in the upper position, and the piston 14B is advanced to open the gripping claws 9Ba and 9Bb. In step S9, the magnetic sensor 19B determines whether a detection signal indicating the open state of the gripping claws 9Ba and 9Bb (the forward movement of the piston 14B) is output, and if NO, steps S8 and S9 are repeated to wait for the output of the open signal. Grip 9B from magnetic sensor 19B
If the release signal of a, 9Bb is output and YES, the grippers of the pick-and-place fingers R, R waiting above are lowered to grip the work W and to remove it from the jig pin S.

When the extraction is completed, the switching solenoid valve 35 is switched by a command from the control circuit 31 according to a signal from the pick-and-place (not shown) or a signal from a timer or the like, and the pressure fluid sent to the cylinder 21A is shut off. The piston is pushed by the force of the spring and
A retreats and becomes a fixed-side protrusion. This ends the inversion cycle. In the case of the fixed positioning pin 24 instead of the second moving projection, in step S10, the switching solenoid valve 32 is switched by instructing the cylinder body 2 to be inverted by 180 ° to return to the initial start state. It is. Then, in the next step, it is determined whether reversal is completed and YES
If so, the inversion cycle ends.

[0031]

As described above, the present invention has the following effects. According to the first and second aspects of the present invention, stable positioning can be performed even when the outer peripheral surface of the workpiece is a non-cut surface and there is an individual difference in the outer peripheral shape. In addition, a single type of gripping claw can be used to grip a variety of workpieces, thereby reducing the manufacturing and storage costs of various types of gripping claws.

According to the third aspect of the present invention, since the rotational positioning after the reversal of the workpiece is constant, the flow of the next operation process is improved. According to the fourth aspect of the present invention, since two moving projections are provided for rotationally positioning the work, the first and second retreating positions can be determined by determining the retreat positions of the two moving projections.
There is no need to return the vertical position of the second gripper, and the rotation position of the work can be kept constant only by switching between the fixed side and the movable side of the movable projection, and the operation of returning the first and second grippers to their original positions. Becomes unnecessary and work efficiency is improved.

[Brief description of the drawings]

FIG. 1 is an explanatory side view of the present invention.

FIG. 2 is an explanatory top view of the present invention.

FIG. 3 is a diagram of a reversing drive mechanism of the turning drive means.

FIG. 4 is an opening and closing mechanism diagram of a gripping means.

FIG. 5 is a top view showing another embodiment of the rotation positioning of the work.

FIG. 6 is a block diagram of control.

FIG. 7 is a state diagram of a gripper immediately before a workpiece is inserted.

FIG. 8 is a diagram illustrating a state in which a first gripper is closed after a work is inserted.

FIG. 9 is a diagram showing a state in which the second gripper is opened after reversing from the state of FIG. 8;

FIG. 10 is a diagram showing a control flow.

FIG. 11 is a view showing a conventional work reversing device.

FIG. 12 is a view showing the reversing mechanism of FIG. 11;

FIG. 13 is a view showing the gripper opening / closing mechanism of FIG. 11;

[Explanation of symbols]

 2 Cylinder body 3 Pinion shaft 5C, 5D, 19A, 19B Magnetic sensor 7 Revolving body 8A, 8B Gripper body 9Aa, 9Ab, 9Ba, 9Bb Gripping claw 13A, 13B, 21A, 21B Cylinder 14A, 14B Piston 23A, 23B Projector 24 Positioning pin 26a Emitter 26b Receiver R Pick and place finger S Jig pin

Claims (4)

[Claims] 1. A method of reversing a work having at least one hole penetrating between two surfaces, comprising two sets of grippers, which are concentric with a gripping center and can be opened and closed separately, are provided at a center of a thickness of the work. And one end of a jig pin that can be inserted into a hole of the work is gripped by one of the two sets of grippers, using a reversing device that can rotate integrally with an axis orthogonal to the grip center. Through the jig pin, grip the other end of the jig pin protruding from the work with the other gripper, flip the axis of the jig pin, open the gripper that was gripped earlier, and take out the work. A method of reversing the center of a hole of a workpiece via a jig pin without directly gripping the workpiece before and after the reversal. 2. A device for reversing the front and back of a work having at least one hole penetrating between the two surfaces, the jig pin being insertable into the hole of the work and being longer than the distance between the two surfaces. A pair of gripping means provided in parallel with two sets of grippers capable of gripping both ends of the jig pin and capable of being opened and closed by independent opening / closing drive mechanisms, each having the same gripping center, and the gripper gripped by the gripping means. Turning means for turning the axis of the jig pin and reversing the position; and controlling means for operating the respective gripping means for independently opening and closing the two sets of grippers and the turning drive means for turning and positioning the two sets of grippers independently. After inserting the hole of the work into the jig pin one end of which is gripped by one gripper and gripping the other end of the jig pin protruding from the work by the other gripper, the jig is rotated by the rotation driving means. A work reversing device characterized by reversing the front and back of a work by turning the pin to a position where the axis of the pin is reversed. 3. A fixed projection provided on one gripper of a pair of gripping means, to which a side surface of the workpiece can abut, and a fixed projection of the workpiece on the same side of the workpiece with respect to the fixed projection with respect to the gripping center of the workpiece. A movable projection that is provided on the side surface and is capable of moving forward and backward to press and rotate the work is provided, and both ends of the jig pin inserted into the hole of the work are gripped by a pair of gripping means, and then moved. 3. The work according to claim 2, wherein the projection is advanced, the workpiece is rotated about the jig pin, and the workpiece is brought into contact with the fixed projection.
3. The work reversing device according to claim 1. 4. A pair of gripping means provided on both sides of the center of gripping the workpiece in parallel in a direction perpendicular to the gripping center, and a retreating end can be positioned at an arbitrary position to press the same side surface of the workpiece. Two movable projections which can be moved forward and backward, and one of the two movable projections is moved forward when one of the two movable projections is positioned at the retreat end, or the one is advanced when the other is positioned at the retreat end. Control means for controlling the forward and backward movements of the two moving projections and the movement of the gripping means are provided in parallel,
After grasping both ends of the jig pin inserted into the hole of the work by a pair of grasping means, one of the moving protrusions is positioned at the set retreat end position, and the other moving protrusion is moved forward to jig the work. 3. The work reversing device according to claim 2, wherein the work is turned around a pin to press and abut against a moving projection which positions the work backward, so as to perform rotation positioning with respect to the hole center of the inverted work.