JPS594269B2 - material handling equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to material handling equipment, and more particularly to an improved high speed 15 material handling equipment.

In many cases there is a need for a device that can be used to automatically move a workpiece from one position to another. Examples of such equipment can be found in Applicant's US Canadian publication entitled "Material Handling Equipment" published August 3, 1976.
No. 3,973,422, my U.S. Pat. No. 4,002,245 (now reissued as RE 29797 on October 10, 1978) entitled ``Material Handling Apparatus with Grasping Device for Moving''. Each of these devices is particularly suitable for grasping a workpiece in one position, moving it to another position, and releasing the workpiece. While these devices are particularly suited for this purpose, it is an object of the present invention to provide a material handling device that operates more quickly and provides a greater range of motion. 35 The present invention is embodied in a material handling device for moving workpieces.

The device is equipped with a gripping device for selectively gripping the workpiece to be moved. The first support device supports the grasping device for movement along a first path, and the second support device supports the grasping device for movement along a second path. The camshaft is rotatably supported, and the D1 cylindrical cam is mounted as a second cam so as to rotate together with the camshaft.
The first follower wheel is supported for reciprocating motion about an axis disposed transversely to the axis of the camshaft and engages the cylindrical cam for reciprocating motion upon rotation of the camshaft.
A second follower wheel engages the second cam and is movable upon rotation of the camshaft. The first motion conversion device converts the reciprocating motion of the first driven vehicle about the axis of the first driven vehicle into movement of the grasping device along a first path. The second movement converter is a second motion converter.
Converting the movement of the follower vehicle into movement of the grasping device along the second path. The invention will be explained below with reference to the drawings.

1-6, reference numeral 11 generally indicates material handling equipment constructed in accordance with a first embodiment of the present invention.

This material handling device 11 includes a drive motor 12, a cam and follower device 13, a support structure 14 and a workpiece gripping device 15.
Equipped with As will become clear below, these elements are configured such that the workpiece gripping device 15 is moved along a predetermined path. Workpiece gripping device 15, shown only in FIG. 1, includes a pair of pivoting jaws 16 which are actuated by actuating cylinders 17 between an open release position and a closed gripping position.

Grasping device 15 may be any known type of device that is commercially available. The grasping device 15 is shown only in FIG.
1 in any desired orientation.

Arm 21 is attached in any known manner to the disc assembly, designated generally by the reference numeral 22 and shown in detail in FIG. The disc assembly 22 supports a pair of depending guide pins 23, 24 which are held in place by clamp plates 25, 26, respectively. pin 23
, 24 are suitably supported for axial movement within a pair of bushes 27, 28 which are mounted on a substantially cylindrical support assembly 29.

The support assembly 29 is rotatably mounted on the upper wall of the housing assembly 31 by anti-friction bearings 32.
Disc 22 is therefore rotatably supported by assembly 29 and bearing 332 and is axially slidable relative to screw assembly 29 by bushes 27,28.

The rotational and axial movement of the disk 22 and therefore of the grasping device 15 supported thereby is controlled by the cam and follower assembly 13. Referring to this portion of the structure, it can be seen that the drive motor 12 includes an output shaft 33 drivingly coupled to a worm gear 34 which is mounted on spaced bearings 35 (FIG. 3).

The worm gear 34 meshes with a worm wheel 36 which is fixed in any suitable manner to the camshaft 37. camshaft 37
is pivoted within housing 31 by any suitable force, such as spaced bearings 38, 39. Two cams are mounted between bearings 38 and 39 to rotate together with camshaft 37. These cams include a cylindrical cam, generally designated by the reference numeral 41, and a front force cam, generally designated by the reference numeral 42. The cylindrical force '1.41 controls the rotational or reciprocating movement of the gripping device 15, while the front cam 42 controls the axial or vertical movement of the gripping device 15. A plurality of roller followers 43 are mounted on pins 44 that extend radially from an annular collar 45 formed on the lower end of support assembly 29 . Roller follower 43
cooperates with the cylindrical cam 41 to cause reciprocating movement of the support assembly 29, disc 22, arm 21 and gripping device 15 upon rotation of the cylindrical cam 41. The cylindrical cam 41 ensures that during a given operating cycle the support assembly 29 and the above-mentioned elements, in particular the grasping device 15, rest in a first angular position and rotate to a second angular position;
It is shaped to return to the first angular position through a rest stage. This cycle of operation takes place during a single revolution of the camshaft 37. It is believed that alternative operating cycles will be apparent to those skilled in the art since it is clear to those skilled in the art how such changes in cycle may be accomplished. The front cam 42 is formed on a surface adjacent to the cylindrical cam 41. The lever 47 is pivoted between the two cams 41, 42 on a shaft 48 which is attached to the housing 31 in any suitable manner. A lever 47 supports a roller follower 49 in the middle of the end.
This follower wheel is received in the cam groove 46 in such a way that when the camshaft 37 rotates, the rotation of the shaft 48 causes the lever 47 to vibrate. The pin 51 at the lower end of the lever 47
is connected to the link 52.

The opposite end of this link 52 is connected by a pivot pin 53 to an upright forked arm 54 of a bellcrank, generally designated by the reference numeral 55.
It is rotatably connected to. The bell crank 55 is rotatably supported on a pivot shaft 56 by the housing 31. The bellcrank 55 has a second forked arm 57, the end of which supports an inwardly extending pin 48 which pivots on a roller 59. Roller 59 engages the underside of collar 61. Collar 61 is attached to the lower end of a tube 62 which extends through the center of support assembly 29 and is axially guided by a pair of bushes 63.
The upper end of tube 62 is attached to disk 22 by machine screws 64. The tab-like member 65 is juxtaposed to the lower end of the collar 61 and forms a horizontally extending shoulder 66 such that the roller 59 is normally captured between the shoulder 66 and the collar 61.

...The tab-like member 65 passes through the hole 69 of the collar 61 and the tube 6.
2 is threaded into a reduced diameter threaded end 67 of a rod 68 which extends through the interior of the rod 68. The central bore of tube 62 is formed with a shoulder 71 near its midpoint. Coil compression spring 72 engages shoulder 71 at its lower end and engages a locking nut 73 mounted on the upper end of rod 68. As will be revealed later, the spring 72 is connected to the arm 2 for safety reasons.
1 and gripping assembly 15 to allow the rod 68 to move downwardly. The operation of the embodiment of FIGS. 1-6 is as follows.

Motor 12 is driven continuously or periodically to produce a single revolution of camshaft 37. Figure 1 shows the mechanism in situ. In this position, the gripping jaws 16 are opened and the workpiece is positioned adjacent to the gripping jaws so that it can be received and gripped by any suitable device. The cylinder 17 is now actuated, closing the jaws 16 and grasping the workpiece.
When the camshaft 37 rotates, the cylindrical cam 41 is in the rest position and the arm 21 is in the first angular position. The front cam groove 46 is shaped so that when the camshaft 37 rotates clockwise in FIG. 6, it presses the follower wheel 49 and turns the lever 47 counterclockwise to the right. This rotation is link 5
2 and the bell crank 55 in the clockwise direction.
is rotated around its support shaft 56. roller 59
engages the underside of collar 61 and forces the end of tube 62 upwardly. During this upward movement, the tab 65 is also raised due to the action of the spring 72. This upward movement continues until the front cam groove 46 reaches its rest position. During this upward movement, disk 22 and pins 23, 24 are moved upwardly by virtue of their axial relationship with support assembly 29.

The workpiece gripped by gripping assembly 15 is therefore raised. When the camshaft 37 continuously rotates, the cylindrical cam 4
1 causes the entire assembly to rotate in cooperation with the follower wheel 43. Since the disc 22 is effectively keyed to the support assembly 29 by the action of the pins 23, 24, the arm 22 and grasping assembly 15 rotate from their first angular position to their second angular position. At the completion of this movement, follower wheel 49 is moved from the resting portion of front cam groove 46 and lever 47 and bell crank 55 are again pivoted to lower arm 22 and grasping assembly 15. As mentioned above, this downward movement is effected by gravity, and spring 72 will only deflect if arm 21 or grasping assembly 15 is prevented from moving downwards. At this point, cylinder 17 is actuated to release the retained workpiece from jaws 16. The downward movement described above occurs during another rest cycle of the front cam 41.

At the completion of the lowering operation, the front cam 41 causes the follower vehicle 43 to rotate again, but this time in the opposite direction. The arm 21 thus rotates back to its original position. The above-mentioned passage and operation cycle can be changed by changing the shapes of the grooves of the front cam 42 and the cylindrical cam 41.

Additionally, the opening and closing of the jaws 16 and the starting and stopping of the motor 12, if desired, can be controlled in a known manner by using limit switches. The second embodiment of the present invention is the seventh to
14 and is generally designated by the reference numeral 101.

The material handling device 101 is substantially the same as that of the embodiment described above, but this embodiment includes two cylindrical cams to effect movement in each path of motion. Additionally, a different type of overload relief mechanism is used, and in this embodiment both motion paths are rectangular in shape. The material handling device 101 includes a drive motor 102, a cam and follower device 103, a support structure 104, and a grasping device 105.

Grasping device 105 includes a pair of rotatably supported jaws 106 which are operated in any known manner between an open position and a grasping position, such as by a pneumatically actuated cylinder 107. The grasping device is suitably secured to the end of arm 108 and supported by the arm in any selected orientation. Arms 108 are attached to a pair of rods 109, and these arms are slidably supported by a support mechanism for movement as described below.

Rod 109 is slidably supported by a bush (not shown) formed in the gear link assembly, generally designated by reference numeral 111. The gear link assembly 111 has a horizontally extending hole 112 through which the rod 109 is inserted.
Further, the carriage assembly 111 has a vertically extending hole in which a bushing 113 is provided which is attached to the top and bottom walls of the housing 115 of the support assembly 104. A pair of rods 1
The gear link assembly is slidably supported for vertical movement on the gear ring assembly 14. Thus, as can be seen, the gear link 111 is supported for vertical up and down movement on the rod 114, and the rod 109 is supported on the gear link 111.
It is slidably supported so as to move inward and outward, and moves vertically together with the gear ring. The mechanism for moving gear link 111 and rod 109, and the grasping mechanism 105 supported thereby, includes a drive motor 102.

The output shaft of this drive motor is connected to a worm gear 116 (
Figure 7) is supported. The camshaft 118 is secured to the housing 115 by a pair of spaced bearings 119 (FIG. 8).
supported within. Camshaft 11 between bearings 119
8, a first cylindrical cam 121 and a second cylindrical cam 122 are attached. The follower vehicle and motion transmission mechanism are gearline 111
and cooperates with the cylindrical cam 121 to produce vertical movement of the grasping device 105.

The mechanism includes a plurality of roller followers 123 supported on a shaft 124 supported by a support collar 125. Support collar 125 is supported by housing 115 for oscillatory movement on axis 126 . axis 1
26 is connected to arm 127 by an overload release device, generally designated by reference numeral 128. Although this overload release device 128 combined with the follower vehicle 123 is not shown in detail, it is the same as that combined with the cylindrical cam 122.
This will be explained in more detail below. A pin 129 is carried at the outer end of the arm 127 and is received in a groove formed by a bearing block 131 which is fixed with the gear ring 111.

Therefore, arm 1 about the axis defined by axis 126
The oscillating movement of 27 thereby causes the supported gear ring and gripping device 105 to move vertically. A plurality of roller followers 132 are combined with the cylindrical cam 122.

These roller followers are connected to the collar 1 attached to the shaft 135.
It is supported on a pin 133 fixed to 34. axis 1
35 is pivoted to the housing 115 by spaced anti-friction pairings 136. A similar device is used to support collar 125, as described above. A disk 137 having a plurality of pockets 138 is attached to shaft 135.

Ball 139 is urged into engagement with pocket 138 by compression spring 141 to form an overload relief 1 drive connection between disc 137 and hub 142 integrally formed with arm 143. There is. The preload of spring 141 is set by screw 144. The roller follower 145 is the arm 14
3 and engages within a slot 146 formed in block 147.

The block 147 is attached to the inner end of the rod 109 (FIG. 14).As can be seen, the reciprocating movement of the shaft 135 about its axis causes the rod 10
The extension of the slot 146 adapted to receive the follower wheel 145, which causes a rotational movement of the arm 143 so that the gear 9 reciprocates back and forth, allows this reciprocating movement regardless of the vertical position of the gear link 111. do. As in the previous embodiment, the movement path of the grasping device 105 is formed by cams 121 and 1222.
It is related to the shape of Two possible paths of motion are shown at 10th and 11th. First, considering the path of motion according to FIG. 10, the original position is indicated by point 151. At this point, when the camshaft 118 rotates, the cam 122 is in the rest position and the rear wheel 132 is not activated. On the other hand, cam 1
21 is in the drive position, causing rotation of the overload release mechanism 128 and the rear wheel arm 127 in the counterclockwise direction as viewed in FIG. Thus, the gripping device 105, which was previously actuated to grip the workpiece at position 151, is now moved to position 152 by movement of gear link 111 along rod 114.
be forced to rise to Cam 121 then reaches its rest position and cam 122 reaches its drive position. When this occurs, the gear link 111 is maintained in its upper position and the cam 12
2 rotates the arm 143 in the clockwise direction as shown in FIG.
causes the rotation of This causes rod 109 within gear link 111 to move to the outer position indicated by point 153.
This causes a sliding movement. As mentioned above, this movement of the rod 109 causes the slot 14 in which the follower vehicle 145 is received.
6, this is possible even when the gear link 111 is in its raised position. Gear ring 111 and grasping device 105
When reaches point 153, cam 122 advances to its rest position and cam 121 is actuated again to rotate arm 127 in the clockwise direction b as shown in FIG. Place device 105 at position 154
let it descend to

At this point, jaws 106 are released and the workpiece is lowered at point 154. Grasping device 105 then moves from point 154 to point 153.
, 152, 151 to the original position. The above-mentioned operating procedure is performed by connecting appropriate switches, such as switches 155 and 156, to the cam 1 mounted on the camshaft 118.
57,158. It is believed that it will be clear to those skilled in the art how such sequences can be used. Switches 155, 156 can control grasping device 105 and motor 102, for example. FIG. 11 shows another possible operating procedure.

In this case, the cams 121 and 122
53 is first moved horizontally from the original position 161 to position 162 by the cam 122, and by the action of the cam 121 it moves to point 1.
63 and is raised to position 164 by cam 122.
4 and lowered by cam 121 to point 161. Again, limit switches for other timing devices may be incorporated to properly operate grasping device 105 and control motor 102. As mentioned above, overload relief devices are incorporated between each shaft 126, 135 and the elements driven by them (gear link 111 or rod 109).

These overload relief devices are disclosed in U.S. Patent Application No. 19, filed March 12, 1979, entitled "Overload Relief Mechanisms."
It may be of the type shown in No. 910. When an obstacle is encountered that prevents further movement, the balls 139 are pressed outward against the action of the spring 141, so that the rotational movement of the shaft is not transmitted to the rotational movement of the respective arm 127 or 143. Do it like this. The device re-engages when this obstruction is removed. 15 to 19 show the third embodiment of the present invention.
A material handling device constructed in accordance with an embodiment of the invention is generally designated by the reference numeral 201.

This material handling device 201 has certain features common to the two previously described embodiments. For example, in this embodiment, the gripping device and the workpiece associated therewith are arranged to oscillate about an axis, and as in the embodiment of FIGS. It is movable in a reciprocating manner along another axis parallel to . Similar to the embodiment of FIGS. 7-14, this material handling device 201 uses two cylindrical cams. The material handling device 201 comprises a gripping device and a support arm as in the two embodiments described above.

Although such a device is not shown in FIGS. 15-19, it can take the same form and have the same support arrangement as shown in FIGS. 1-6. Support mechanism 20
2 is incorporated to provide support for the grasping device. A cam and follower mechanism, generally designated by the reference numeral 203, is incorporated to provide the desired path of motion. The cam and follower mechanism 203 is operated by a drive motor, generally designated by the reference numeral 204. The grasping device and arm are attached to disk 205 in the manner described in connection with the embodiment of FIGS. 1-6. A pair of pins 2 extending downward
06, 207 are attached to the disk 205. These pins 206, 207 are slidably supported within a support housing generally indicated by the reference numeral 208 by a pair of spaced apart bushings 209 and a single bushing 211, respectively. Support: The housing 208 is located outside the assembly.
- Rotatably supported within housing 203 by anti-friction bearing 202.

The central column 214 is attached to the disc 205 and is slidably supported by a housing 208 by means of a device including a bush 215.

Collar 216 along with another collar 217 on column 214
is attached to the lower end of to provide a circumferential groove 218. Roller 219 is received within groove 218 and rotates arm assembly 22.
It is supported on a shaft attached to the outwardly extending portion of 2. The arm assembly 222 includes a shaft portion 223 which is mounted on a shaft 225, and the shaft 225 is connected to the housing 21 by spaced anti-friction bearings 226 (FIG. 16).
It is mounted on a shaft at 3. The hub portion 223 has an axially extending bore 2 terminating in an end bore 228 in which a ball 227 is received.
24.

The compression spring 229 is a disk 23 attached to the bulb 233.
Press the ball 227 into the pocket 231 formed by the ball 227. Therefore, the overload release connection includes the same elements as in the embodiment of FIGS. 7-14--branch 233 and arm assembly 22.
It is formed between the two. A shaft 234 is attached to the hub 233 and supports a roller follower 235 at its outer end.

These roller followers 235 cooperate with a first cylindrical cam 236 to cause reciprocating movement of arm assembly 222 about an axis defined by shaft 225. The cylindrical cam 236 is connected to the housing 21 by spaced bearings 238.
The camshaft 237 is mounted on the camshaft 237 mounted on the camshaft 3. A second cylindrical cam 239 is also attached to the camshaft 237. A roller follower 241 (FIG. 19) is supported on a pin 242 and
cam 239. Roller follower 241 and pin 2
44 indicates that the movement of the cylindrical cam 239 and the follower wheel 241 is about the axis defined by the bearing assembly 212.
Support . . . is supported by the lower end of the housing 208 to cause vibration of the housing 208. Camshaft 237 has a worm wheel 243 attached to its outer end.

This worm wheel 243 is driven by a worm 244 attached to the output shaft of the motor 204. cam 2
45 and 246 are attached to the outer end of camshaft 237 and cooperate with limit switches 247 and 248, respectively, to control the operating cycle.

As in the case of the two previous embodiments, the desired movement path can be obtained by this mechanism, which is related to the shape of the cylindrical cams 236, 239.

Figure 16 shows possible movement paths. Following this path, the grasping device is normally in its original position 251. In this original position, the other parts of the device are in the configuration shown. As camshaft 237 rotates, cam 236 rotates arm assembly 222, thereby raising post 214 and attached disk 205 to point 252. When this occurs, the cylindrical cam 239 is in its rest position;
Therefore, around the axis of the housing assembly 208...
No reciprocation or rotation of housing assembly 208 occurs.
When point 252 is reached, cam 236 is at rest and cam 239 begins its drive movement. Therefore, support...
The housing 208 and the arm and gripping device supported thereby are rotated to position 253. Once position 253 is reached, cam 239 is again at rest and cam 236 causes disk 204 to move axially from point 253 to point. Next, the workpiece is placed at this point 25 as in the previous embodiment.
4, it is lowered by releasing the grasping device. Next, the mechanism is point 2
54, 253, 252 and 251 and returned to its original position. Having thus described several material handling devices with a wide range of motion, it will be readily appreciated that their construction allows for very rapid operating cycles.

It will be appreciated that an overload relief device is also incorporated to prevent damage to the equipment. The present invention is susceptible to various changes and modifications without departing from its spirit and scope.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a material handling device according to the invention, with a portion cut away to show construction details. FIG. 2 is a top view of the embodiment of FIG. 1 with the grasping device and its support arms removed to show certain portions of the structure in detail. FIG. 3 is an enlarged cross-sectional view taken along a plane parallel to the plane of FIG. 2 passing through the axis of the camshaft. Figure 4 is line 4-4 in Figure 3.
FIG. 5 is a partially sectional side view taken in the direction of arrow 5 in FIG. 4. FIG. Figure 6 shows the line 6- in Figure 3.
FIG. 6 is a cross-sectional view according to No. 6. FIG. 7 is a top view of a material handling device according to a second embodiment of the invention. Figure 8 is the 7th
8 is a cross-sectional view of the embodiment of FIG. 7 taken along line 8-8; FIG.
FIG. 9 is a cross-sectional view taken along line 9--9 of FIG. 10th
The figure is a schematic diagram showing one possible movement path for the embodiment of FIGS. 7-9. 11 is a schematic diagram of parts similar to FIG. 11, illustrating other possible movement paths for this embodiment; FIG. FIG. 12 is a cross-sectional view taken along line 12--12 of FIG. 13 is a partially sectional end view taken in the direction of arrow 13 in FIG. 8. FIG. FIG. 14 is a side view taken in the direction of arrow 14 in FIG. 12, with the cover plate removed. FIG. 15 is a top view of a third embodiment of a material handling device according to the present invention, with the grasping device removed to show the structure in detail. FIG. 16 is a schematic diagram showing the movement path of the embodiment of FIG. 15. FIG. 17 is a cross-sectional view taken along line 17--17 of FIG. 18. FIG. 18 is a cross-sectional view taken along line 18--18 of FIG. 15. Figure 19 is the first
5 is a cross-sectional view taken along line 19-19 of FIG. 5; FIG. 11...
Material handling device, 12... Drive motor, 13... Cam and follower device, 14... Support structure, 15... Grasping device, 16... Jaw, 17... Actuation cylinder, 21
... Support arm, 22 ... Disc (assembly), 23, 24
... Guide pin, 25, 26 ... Clamp plate, 27,
28...button, 29...support assembly, 31...
... C: Ring assembly, 32... Bearing, 3
3... Output shaft, 34... Worm gear, 35...
Bearing, 36... Worm wheel, 37...
Camshaft, 38, 39... Bearing, 41... Cylindrical cam, 42... Front cam, 43... Roller follower, 4
4... Pin, 45... Collar 46... Cam groove, 4
7... Lever, 48... Shaft, 49... Roller follower, 51... Pin, 52... Link, 53... Pivot pin, 54... Arm, 55... Bell Crank, 56・
...Axis, 57...Arm, 59...Roller, 61...
・Color, 62...Tube, 63...Butsuyu, 64・
...Machine screw, 65...Tub-shaped member, 66...Shoulder, 67...Screw end, 68...Rod, 69...Hole, 71...Shoulder, 72... Spring, 73... Locking nut, 101... Material handling device, 102... Drive motor, 103... Cam and follower device, 104... Support structure, 105... Grasping device, 106 ...chin, 1
07... Cylinder, 108... Arm, 109... Rod, 111... Gear link assembly, 112... Hole,
113...butsuyu, 114...rod, 115.
... Uzing, 116... Worm gear, 117.
...Worm wheel, 118...Camshaft, 119.
... Bearing, 121, 122 ... Cylindrical cam, 12
3... Roller follower, 124... Axis, 125... Collar, 126... Axis, 127... Arm, 128...
Overload release device, 129... Pin, 132... Roller follower, 133... Hiso, 134... Collar, 13
5... Shaft, 137... Disc, 138... Pocket, 139... Ball, 141... Compression spring, 142
...Hap, 143...Arm, 144...Screw, 14
5... Roller follower, 146... Slot, 147...
...Protsuku, 151, 152, 153, 154...
Point (position), 155, 156...Switch, 157,
158...Cam, 161...Original position, 163, 16
4... Point (position), 201... Material handling device, 2
02... Support mechanism, 203... Cam and follower device,
204...1 drive motor, 205...disk, 206
, 207... Pin, 208... Support...Using,
209,211...butsuyu, 214...pillar, 21
5...Butsuyu, 216,217...Color, 21
8...Groove, 221...Shaft, 222...Arm assembly,
223...B part, 225...Shaft, 226...
・Bearing, 227...Ball, 228...Edge hole, 229...Compression spring, 231...Pocket,
233... Hub, 234... Pin, 235... Roller follower, 236... Cylindrical cam, 237... Camshaft, 238... Bearing, 241... Roller follower,
242... Pin, 243... Worm wheel, 2
44...Worm, 245,246...Cam, 24
7,248...Limit switch, 251...Original position, 252,253,254...Point (position).

Claims (1)

[Claims] 1 a gripping device for selectively gripping the workpiece to be moved; a first support device supporting the gripping device for movement along a first path; and a gripping device for supporting the gripping device for relative movement along a second path. a second support device which is above the first support device and supports the grasping device; a camshaft rotatably supported; a roller-type cam having a raised cam surface for rotation with the camshaft; a second camshaft mounted to rotate with the camshaft;
Cam: A plurality of pins that are supported to reciprocate around a driven vehicle axis that is arranged transversely to the axis of the camshaft, and that extend radially outside the axis of reciprocating movement, and the pins. and at least two of the rollers are in constant contact with opposite sides of the cam surface of the roller-type cam during rotation of the camshaft. The first driven vehicle is arranged to reciprocate around the axis of the driven vehicle, and the second driven vehicle is
a second follower wheel constantly engaged with the cam and capable of moving as said camshaft rotates; reciprocating motion of said first follower wheel about the axis of said first follower wheel in said first path; a first motion converting device that converts the motion of the grasping device along the second path; and a second motion converting device that converts the motion of the second driven vehicle into the motion of the grasping device along the second path. A material handling device for moving workpieces, characterized by: