Loading and unloading mechanism

An improved device for offering high speed transfer of articles between first, second and third stations. The device includes a pair of gripping devices each of which is movable along a first path with the first gripping device being operative to pick up an article at the first station and deposit it at the second station. The other gripping means is effective to grip the article at the second station and move it to the third station for release.

BACKGROUND OF THE INVENTION 
This invention relates to a loading and unloading mechanism and more 
particularly to an improved material handling device for transferring an 
article from a first station to a second station and then removing the 
articles from the second station and placing it at a third station. 
Various types of material handling devices have been proposed for moving 
articles from one station to another. Such devices have particularly 
utility in production lines where they can be used to reduce the necessity 
for an operator to do tedious labor and also can be used in areas where it 
is desired to protect the operator from possible injury by the associated 
machinery. Frequently, it is desirable to take an article from a first 
location, place it in a machine for an operation and subsequently remove 
the article from the machine and place it at another location. Devices 
have been proposed for this purpose that use a single gripper that picks 
up the article at the first station, transfers it to the machine and then 
removes it from the machine an places it at the other station. By using a 
single gripper, however, the speed of production is sustantially reduced. 
Alternatively, devices have been proposed that sequentially move an 
article in a hand-over-hand fashion down a sequence of steps. Such 
devices, however, are usable only when the successive stations are aligned 
with each other. 
It is, therefore, a principal object of this invention to provide an 
improved loading and unloading mechanism for handling articles. 
It is another object of this invention to provide a loading and unloading 
mechanism that permits two articles to be handled at the same time, thus 
increasing the speed of production. 
It is a further object of this invention to provide a loading and unloading 
mechanism that is capable of handling more than one article and which uses 
a simplified drive mechanism. 
SUMMARY OF THE INVENTION 
A first feature of this invention is adapted to be used in a material 
transfer device for sequentially moving articles from a first station to a 
second station and from the second station to a third station. Such a 
device comprises a single driven member and motion transfer means for 
moving said single driven member between a first position and a second 
position. First gripping means adapted to selectively grip and release an 
article is supported for movement along a path from a first position 
wherein an article at the first station may be gripped and a second 
position wherein the gripped article may be deposited at the second 
station. Second gripping means which are also adapted to selectively grip 
and release a workpiece is supported for movement along a path from a 
first position wherein an article at the second station may be gripped and 
a second position wherein the gripped article may be deposited at the 
third station. Mechanical motion translation means are provided for moving 
the first gripping means between its first position and its second 
position and the second gripping means between its first position and its 
second position in response to movement of the single driven member 
between its first position and its second position. 
Another feature of this invention is also adapted to be embodied in a 
material transfer device for sequentially moving articles from a first 
station to a second station and from the second station to the third 
station. In accordance with this feature of the invention, a drive member 
and a support member are interrelated with motion transfer means for 
moving the drive member and the support member between first positions and 
second positions and for moving the drive member relative to the support 
member between relative positions and second relative positions. First and 
second gripping means each adapted to selectively grip and release an 
article are each supported upon the support member for movement along 
paths from a first position to a second position. In its first position, 
the first gripping means is adapted to grip an article at the first 
station and deposit it when the first gripping means is in its second 
position. The second gripping means adapted to grip an article at the 
second station when in its first position and deposit an article at the 
third station when in its second position. First mechanical motion 
translation means are operative between the drive member and the first 
gripping member for moving the first gripping member between its positions 
in response to movement between the drive member and the support member 
from their first relative positions to their second relative positions. 
Second mechanical motion translation means is operative between the drive 
member and the second gripping member for moving the second gripping 
member between is first position and its second position in response to 
relative movement between said drive member and said support member from 
their first relative positions to their second relative positions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring first to FIGS. 1 through 3, a loading and unloading mechanism 
constructed in accordance with an embodiment of the invention is 
identified generally by the reference numeral 11. The loading and 
unloading mechanism 11 is particularly adapted for use in picking up 
articles at a first position from a conveyor 12 and placing them into a 
work station 13. The articles are then removed from the work station 13 
and placed upon a discharge conveyor 14. 
The device 11 includes a supporting member 15 that is adapted to be 
sequentially raised and lowered by a mechanism to be described. The 
supporting member 15 has a pair of outwardly extending arms each of which 
terminates in a respective portion 17, 18. The bearing portions 17 and 18 
each support a pair of respective guide rods 19, 21. The guide rods 19 
have affixed at their forward end a gripping device 22 that includes a 
pair of jaws 23 that are sequentially opened and closed in a suitable 
manner, as by means of a pneumatically operated cylinder 24. In a like 
manner, a gripping mechanism 25 is supported at the outer ends of the 
guide rods 21 and includes a pair of gripping jaws 26 that are operated by 
a pneumatic cylinder 27. A block 28 having a groove 29 (FIG. 5) formed 
therein is affixed to the guide rods 19. A similar block 31 has a similar 
groove and is affixed to the guide rods 19. 
A drive member 32 is provided that is moved vertically with the support 
member 15, in a manner to be described, and which is also rotated while 
the support member 15 is held against rotation. The drive member 32 has a 
pair of outwardly extending arms that carry respective pins 33 and 34 that 
are received in the grooves of the blocks 28, 31, respectively, so as to 
effect reciprocation of the rods 19, 21 and gripping members 22, 25 in a 
manner to be described. 
Referring now to FIGS. 4 and 6 through 9, the mechanism for operating the 
support member 15 and drive member 32 will be described. The drive 
mechanism is indicated generally by the reference numeral 35. The support 
member 15 is carried by a pair of depending guide pins 36 and 37 which are 
held in place by means of clamp plates 38 and 39, respectively. The pins 
36 and 37 are suitably supported for axial movement in pairs of bushings 
41, 42 which are, in turn, affixed to a generally cylindrical supporting 
assembly 43. The supporting assembly 43 is, in turn, affixed to a housing 
assembly 44. It should thus be clear that the support member 15 is axially 
slidable relative to the housing assembly 44 by virtue of the bushings 41 
and 42 but is held against rotation. 
The drive member 32 is affixed to a cylindrical post 45 that depends 
downwardly through an opening in the center portion of the support member 
15. The drive member 32 is supported on the upper side of the support 
member 15 in a suitable manner so that the support member 15 will rise and 
lower the drive member 32, in a manner to be described. The cylindrical 
post 45 is supported for axial movement relative to an axially fixed 
sleeve 46 but is keyed for rotation with the sleeve 46 by a key and keyway 
construction indicated at 50. Thus, in addition to being axially movable 
with the supporting member 15, the drive member 32 is rotatable relative 
to it. The mechanism for raising and lowering the supporting member 15 and 
drive member 32 and for rotating the drive member 32 is contained within 
the housing 44. 
Referring to this portion of the construction, a drive motor 47 has an 
output shaft 48 which is drivingly coupled to a worm gear 49 which is 
journalled in spaced bearing 51 (FIG. 6). The worm gear 49 is enmeshed 
with a worm wheel 52 that is fixed in a suitable manner to a camshaft 53. 
The camshaft 53 is journalled in the housing 44 in any suitable manner, as 
by means of spaced bearings 54 and 55. Between the bearings 54 and 55, two 
cams are affixed for rotation with the camshaft 53. These cams include a 
globoidal, roller-type cam, indicated generally by the reference numeral 
56, and a face cam, indicated generally by the reference numeral 57. The 
globoidal roller-type cam 56 controls the rotational or oscillatory 
movement of the drive member 32 while the face cam 57 controls the axial 
or up and down movement of the support member 15 and drive member 32. 
A plurality of roller followers 58 are journalled on pins 59 which extend 
radially from an annular collar 61 integrally formed on the lower end of 
the sleeve 46. The roller followers 58 coact with the roller-type 
globoidal cam 56 and cause an oscillation of the sleeve 46 and 
accordingly, the drive member 32 through the action of the key and keyway 
50 upon rotation of the roller-type globoidal cam 56. The roller-type 
globoidal cam 56 is configured so that during a given cycle of operation, 
the drive member and the components driven by it and particularly the 
gripper devices 22, 25 will dwell at a first angular position (home), 
rotate to a second angular position, go through a dwell stage, rotate to a 
third angular position, dwell again, and then return back to the first 
angular position (home). This cycle of operation is achieved during single 
rotation of the camshaft 53. Alternative cycles of operation are believed 
obvious to those skilled in the art as is how such variations in cycle can 
be achieved. 
The face cam 57 has a cam groove 62 formed in the face adjacent the 
globoidal cam 56. A lever 63 is journalled between the two cams 56 and 57 
on a shaft 64 that is affixed in any suitable manner to the housing 44. 
Intermediate its ends, the lever 63 carries a roller follower 65 that is 
received in the cam groove 62 so as to cause oscillation of the lever 63 
about the shaft 64 upon rotation of the cam shaft 53. 
At a lower end of the lever 63, a pin 65 connects the lever 63 to a link 
66. The opposite end of the link 66 is pivotally connected by a pivot pin 
67 to an upstanding bifurcated arm 68 of a bell crank, indicated generally 
by the reference numeral 69. The bell crank 69 is, in turn, pivotally 
supported by the housing 44 upon a pivot shaft 71. The bell crank 69 has a 
second bifurcated arm 72, the terminal ends of which carry inwardly 
extending pins 73 which journal rollers 74. The rollers 74 are received in 
a circumferential groove 75 formed in a collar 76. The collar 75 engages 
the underside of a collar 77 to which the lower ends of the pins 36 and 37 
are affixed. Pivotal movement of the bell crank 69 in a clockwise 
direction as viewed in FIG. 5 will cause the collar 76 and collar 77 and, 
accordingly, the support member 15 and drive member 32 to be elevated. If, 
however, the support member 15 or drive member 32 or any of the components 
carried thereby engage an obstacle that prevents downward movement, the 
collar 75 can move freely away from the collar 77 so that no force will be 
exerted on the obstacle. This provides safety effect. 
The face cam 57 and its follower mechanism is configured so as to give rise 
to a sequence of operations that consist of a dwell, a activating movement 
that effects lowering of the support member 15 and drive member 32, rising 
of the drive member 32 and support member 15, lowering of these members, 
raising of them, and a further dwell operation. 
The total operation of the mechanism will now be described. FIG. 1 
illustrates the mechanism as it appears at rest. In this condition, the 
support member 15 and drive member 32 are elevated so that the grippers 22 
and 25 will also be elevated. The drive member 32 is in a home or neutral 
position so that the gripping members 22 and 25 will be disposed between 
the extreme ends of their two paths of movement. When a cycle of operation 
is initiated by energization of the motor 47, the globoidal cam 56 will 
effect movement of the drive member 32 in a counterclockwise direction as 
shown in FIG. 1. At this time, both the drive member 32 and support member 
15 are still in their elevated positions. This rotation of the drive 
member 32 continues until the pin 33 has caused the block 28 and the 
support rods 19 to have moved to withdraw the gripper 22 to a first 
position that is aligned with the conveyor 12. At the same time, the arm 
carrying the pin 34 will have moved so as to cause the block 31, support 
rods 21 and gripper 25 to move to its first outward position in alignment 
with the work station 13. These relative positions are as shown in FIG. 2. 
When the gripper 22 is aligned with the conveyor 12 and the gripper 25 is 
in position at the work station 13, the cam 56 goes into a dwell stage and 
the face cam 57 is effective to cause lowering of the support member 15 
and, accordingly, lowering of the drive member 32. Hence, the grippers 22 
and 25 are both lowered. In the event an obstacle prevents such downward 
movement, the drive member 32 and support member 15 will be retained 
upwardly while the bell crank 69 will be pivoted in a counterclockwise 
direction and cause the collar 76 to move downwardly away from the collar 
77. Assuming that there is no obstacle beneath the supporting member 15 or 
drive member 32 or the elements carried thereby, the grippers 22 and 25 
will be lowered so that they will be in alignment with the conveyor 12 and 
work station 13. At this time, the respective gripping jaws 23, 25 will be 
held open. When the cam 57 has effected full lowering, the grippers 22 and 
25 are actuated by the cylinders 24 and 27 so that a workpiece will be 
gripped from the conveyor 12 and if a workpiece is present in the station 
13, it will also be gripped. 
During this downward movement and the operation of the grippers 22 and 25, 
the roller cam 56 will be in a dwell position. Once the articles are 
gripped, the face cam 57 causes the drive member 21 and support member 15 
to be re-elevated. Once this elevation has been completed, the face cam 57 
goes into a dwell stage and the roller globoidal cam 56 goes into an 
active stage. This active stage of the roller globoidal cam 56 effects 
pivotal movement of the drive member 32 in a clockwise direction. This 
rotation causes the block 28, support rods 19 and gripper 22 to be moved 
from a first position in alignment with the conveyor 12 to a second 
position wherein the article is positioned at the work station 13. At the 
same time, the gripper 25 is moved from its first position in alignment 
with the work station 13 to its second position in alignment with the 
conveyor 14. 
Once the globoidal cam 56 has accomplished this movement, it goes into a 
dwell stage and the face cam 57 causes lowering of the support member 15 
and drive member 32 and, accordingly, the grippers 22 and 25. The jaws 23, 
26 are then actuated by operating the cylinders 24 and 25 so that a 
workpiece will be deposited at the work station 13 by the gripper 22 and 
the removed workpiece from the work station 13 will be deposited on the 
conveyor 14 by the gripper 25. The mechamism is then actuated so as to 
return it to the home position as shown in FIG. 1. The mechanism by which 
this is accomplished is believed to be obvious from the foregoing 
description. 
It should be readily apparent that this construction permits a rapid 
handling of a maximum number of workpieces in view of the fact that there 
are two gripping mechanisms each operating in synchronism with each other 
while at the same time avoiding any interference between them. 
Although an embodiment of the invention has been illustrated and described, 
it is to be understood that various changes and modifications may be made 
without departing from the spirit and scope of the invention as defined by 
the appended claims.