JPH05131390A - Mounting structure for multifunctional arm - Google Patents

Abstract

PURPOSE: To provide an attaching structure for supporting an arm over the long axial distance so that the arm may not be slip in the total supporting distance in the attaching structure, requiring no large space in front of the attaching structure, and having low force to be applied to the arm in order to move the arm in the attaching structure. CONSTITUTION: An arm 28 is provided with a pair of separated enlarged sections 37, 47 and an intermediate recessed section 38 located between them. An attaching structure is provided with a first attaching part 41 having an upward opening extending over the length larger than the diameter of the recessed section, a second attaching part 44 provided behind the first attaching part 41, and an intermediate releasing part 46 formed on the attaching structure between the first and second attaching parts. The recessed section 38 of the arm is moved to a part above the opening of the first attaching part and then moved downward, the arm is moved rearward, and therefore, the first and second enlarged sections are housed in the first and second attaching parts.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to mounting a multifunctional arm to a support structure. More particularly, the present invention relates to a method and apparatus for quickly attaching an arm to a support structure that is efficient both in terms of space and time required.

[0002]

Many types of attachment structures exist in the prior art for connecting arms to support structures. Many prior art mounting structures must be disassembled and then reassembled to mount the arm. These structures are unsatisfactory because they require a relatively long time to complete the installation.

A mounting structure on which the arm can be mounted quickly without complete disassembly is the subject of the invention. If the arm is slid into the mounting structure, it is necessary to support the arm over a sufficient axial distance, defined here as the axial support distance, whereby the stress or force of the arm is dependent on the mounting structure. Can be absorbed. Furthermore, if the arm is aligned with the open front end of the mounting structure and is slid into it over the entire axial support distance, it requires a relatively large amount of clearance spacing in front of the mounting structure, which is There are things you can't do.

In some applications utilizing the arm, the space near the mounting structure does not allow much room for moving the parts. There may be insufficient clearance for the arm to be positioned in front of the mounting structure over the entire axial support distance. For this reason described above, prior art constructions are undesirable.

It is self-evident that sufficient axial support distance must be maintained in order to properly support the arm. For the reasons discussed above, it may not be possible to provide an arm that has a length that is adequately supported while at the same time being short enough to fit into a mounting structure.

Another problem with the prior art construction involves the arms utilized to mount electrical equipment which requires complex electrical connections to the power supply and control equipment. As will be appreciated by those skilled in the art, arms designed for quick connection to attachment structures such as those described herein present a real problem if electrical connection is required.

[0007]

Therefore, a multifunctional arm in which the arm is not positioned in front of the mounting structure for coupling and therefore does not require pushing the arm into the mounting structure over the entire axial bearing distance. It is an object of the present invention to provide a mounting structure for

It is another object of the present invention to provide a mounting structure that allows an electrical device to be quickly coupled to a power supply or control device.

[0009]

The present invention includes a mounting structure for mounting an arm to a support structure such as a work transfer assembly. In the disclosed embodiment, the arm is connected to the workpiece gripper handle. In this embodiment, the electrical connection of the gripping handle passes through the arm and mounting structure and into the work transfer assembly.

The disclosed embodiment of the invention includes an arm having a first enlarged area axially spaced from the recessed area. The mounting structure includes a first supporting first expanded area
Including the mounting part. The first mounting portion includes an additional flange or leg that defines an opening that is larger than the cross-sectional dimension of the recessed area. The recessed areas are aligned above the openings and moved down between the flanges into the openings. The arm is then moved rearward until the first enlarged area is received within the first mounting portion.

In a preferred embodiment of the invention, a second enlarged area is formed on the side of the recessed area opposite the first enlarged area. The mounting structure also includes a second mounting portion and an intermediate open portion between the two mounting portions.
When the arm is positioned with the recessed area aligned over the opening described above, the second enlarged area is aligned over the open portion. The arm is then moved downwards and backwards so that the first and second enlarged portions are received within the first and second mounting portions, respectively.

The axial support distance is defined as the distance between the ends of the two mounting portions and is the distance the arm is supported within the mounting structure. It is important that this distance is sufficient to allow the mounting structure to absorb stresses or forces on the arm.
The arm according to the invention is positioned in front of the mounting structure at a distance much smaller than the axial distance prior to mounting. The arm need only be positioned in front of the mounting structure over a distance approximately equal to the length of the first enlarged area. This still provides sufficient axial support distance while at the same time resulting in both a reduction in space and force required to mount the arm as compared to prior art constructions.

In the most preferred embodiment of the present invention, a latching structure latches the arm within the mounting structure. A spring biases the latch member in the second mounting portion to pivot about the axis and force the latch tooth into the notch formed in the second enlarged area. A flange formed on the second enlarged area causes the latch member to pivot against the force of the spring as the arm is moved within the second mounting portion. As the flange is moved past the latch member, the spring biases the latch member back into the notch and the arm is latched.

The second mounting portion has an intermediate slot that includes an upper surface and a lower surface. The locking structure moves the upper surface downwardly toward the lower surface to close the slot and reduce the inner diameter of the second attachment portion, thereby locking the second enlarged area of the arm within the second attachment portion. ..

A flat guide surface is provided near the first mounting portion and a corresponding flat guide surface is formed on the bottom of the first enlarged area. The two flat surfaces align the arm and allow it to be smoothly guided into or out of the mounting structure.

In another aspect of the invention, a quick change electrical connector is mounted on the rear portion of the mounting structure. The arm has a mating electrical connection that plugs into an electrical connector to connect the arm to a power or control device. The flat guide surface ensures that the mating plug portion of the arm and the electrical connector are properly aligned when the arm is moved within the mounting structure.

These and other features and objects of the present invention can be best understood from the following description and drawings.

[0018]

DETAILED DESCRIPTION OF THE INVENTION A work transfer assembly 20 having a gripper handle 22 for gripping a work piece 24 is illustrated in FIG. A series of links 26 with ball joints are used for the grip body handle 2.
2 is connected to the arm 28. The arm 28 is connected to the work transmission device 30 via a mounting structure 32. As illustrated in this figure, the wall and table 33 limit the space available for movement near the arm 28. The wall and table 33 schematically represent another structure that can limit the amount of space available for movement of the arm 28. In a typical environment, there may be multiple industrial machines or conveyors positioned around the work transfer assembly 20, which limit available space.

The arm 28 is received within the mounting structure 32. In the prior art, the arm 28 had to be axially positioned in front of the mounting structure. Such prior art mounting structures often required a relatively large space in front of the mounting structure. In the illustrated environment, there may be insufficient space for the arm to be positioned anterior to the mounting structure 32 over its entire axial support distance. At the very least, the use of prior art structures made it difficult to attach the arm 28 to the work transfer device 30. in addition,
The combination of gripper handle 22, ball jointed link 26, and arm 28 is relatively cumbersome to operate manually, and pushing it into mounting structure 32 over the entire axial support distance is undesirable. Sometimes.

Although the mounting structure 32 and arm 28 are illustrated in combination with the work transfer assembly 20, the teachings of the present invention are for any application in which any type of arm is mounted to the structure. This is true. Although work transfer device 30 provides some motion to arm 28, the teachings of the present invention also apply to mounting the arm to a stationary structure.

FIG. 2 is an enlarged view showing a mounting structure 32 for mounting the arm 28. The ball-jointed link 26 extends forward of the arm 28 and can be adjusted to any one of a number of positions. Links with ball joints are described in US Pat. No. 4,898,
No. 490, the disclosure of which is incorporated herein by reference.

In the disclosed embodiment, the arm 28 comprises a tubular outer member 34 extending forward of the mounting structure 32 and an inner mounting member 35 received within the tubular outer member 34.
The tubular outer member 34 is fixed over the inner mounting member 35 by a clamp 36.

The inner mounting member 35 has a first enlarged area 37 axially positioned in front of the intermediate recessed area 38. The mounting structure 32 includes a mounting plate 40 positioned at a front end and a first enlarged area 37 of the arm 28 that receives the first enlarged area 37.
And a mounting portion 41 of. The mounting plate 40 has an upwardly open channel in which a portion of the first enlarged portion 37 extends forward of the first mounting portion 41 and rests in this channel for reasons to be described below. The first mounting portion 41 has a pair of spaced-apart, opposed flanges 42 and 43 that define a top opening that provides an access slot to the lumen within the inner perimeter of the flanges 42 and 43. The arm 28 and the mounting structure 32 each extend along the axis from the front position to the rear position. Due to the opening between the flanges 42 and 43, the inner circumference of the first mounting part 41 has a radius of 3 mm about this axis.
It does not extend over 60 degrees. A second mounting portion 44 is axially positioned behind the first mounting portion 42 and an intermediate open portion 46 is positioned between the first mounting portion 42 and the second mounting portion 44. ing. The second enlarged area 47 formed behind the recessed area 38 is the second
Received in the mounting portion 44 of the. The inner circumference of the second mounting portion 44 extends around the axis for approximately 360 degrees. The intermediate open portion 46 opens vertically upwards about 180 degrees about the axis described above.

In the preferred embodiment of the invention, the first enlarged area 37 has a first outer dimension and the recessed area 38 is first.
Has a second outer dimension that is less than the dimension. The opening between the flanges 42 and 43 is larger than the second dimension so that the recessed area 38 can pass between the flanges 42 and 43. The dimensions of the channel in the mounting plate 40 are larger than the first outer dimension so that the first enlarged area 37 can pass therethrough. When mounting the arm 28 to the mounting structure 32, the recessed area 38 is positioned over the opening between the flanges 42 and 43 and the first enlarged area 37 is mounted on the mounting plate 4.
A second enlarged area 47 positioned above the 0 channel
Is positioned over the open portion 46. As will be described in more detail below, the arm 28 is then removed from the first and second arms.
The enlarged areas 37 and 47 of the first and second mounting portions 41
And 44, respectively, and can be moved downwards and directions until received.

A stop nut 48 is received within the second mounting portion 44, which includes a handle 50 for locking the arm 28 within the mounting structure 32. A latch member 52 is received in the second mounting portion 44 and latches the arm 28 within the mounting structure 32.

FIG. 3 is a partial cutaway view of the second mounting portion 44 and illustrates a second enlarged area 47, which is larger than the outer dimension of the recessed area 38. Three
With outer dimensions of. The first mounting portion 41 has an inner dimension approximately equal to the inner dimension of the first enlarged area 37, whereas the second mounting portion 44 has a second enlarged area 47.
It should be understood that it has an inner dimension approximately equal to the outer dimension of the. First and second expanded areas 37 and 4
7 can have the same outer dimensions, but it is not necessary. In addition, although sections 37, 38 and 47 are illustrated as cylindrical, they can have some other geometric shape. If areas 37, 38 and 4
If 7 are cylindrical, the outer dimensions mentioned above are their respective diameters.

A notch 56 is formed in the second enlarged area 47. The latch member 52 has notches 56 with latch teeth 62.
A spring 58 about a pivot 60 for receipt therein.
Biased by. The stop nut 48 has a pivot hole 6
0 through which latch member 52 pivots about stop nut 48. When the latch teeth 62 are received within the notches 56, the flange 57 positioned behind the notches 56 prevents movement of the arm 28 outward of the mounting structure 32.

As shown, the latch member 52 extends radially into the lumen defined by the second attachment portion 44. When the arm 28 is moved into the mounting structure 32, the flange 57 contacts the latch member 52 and biases it outward of the lumen. As the flange 57 moves past the latch tooth 62, the spring 58 causes the latch member 52 to pivot radially back into the lumen, causing the latch tooth 62 to move into the notch 56. In this way, the mounting structure is self-latching when the arm 28 is moved therein.

A flat guide surface 63 is shown in the bottom portion of the first enlarged area 37. The flat guide surface 63 is the mounting plate 4
Aligning with the zero mating guide surface ensures that the arm 28 is properly aligned within the mounting structure 32.

Further details of the mounting structure 32 can be seen from FIG. The arm 28 has a tubular outer member 34 connected to an inner mounting member 35 by a clamp 36. The inner mounting member 35 has a first enlarged area 37 and a second enlarged area 37.
2 has an enlarged area 47 and a recessed area 38. The notch 56 is formed near the rear end of the second enlarged area 47, and the flange 57 is formed behind the notch 56. Set nut 48 and handle 50 extend through holes 64 in second mounting portion 44 and through pivot holes 60 downwards. The slot 65 is defined between the upper surface 66 and the lower surface 67 of the second mounting portion 44. The bolt 68 extends upward through a hole (not shown) formed in the lower surface 67 and then through the pivot hole 60. The stop nut 48 is received on the bolt 68 and when turned by the handle 50 tightens the upper surface 66 downwardly toward the lower surface 67,
By reducing the inner dimensions of the mounting portion 44 of the arm 28
Lock in the mounting structure and firmly grip the second enlarged area 47.

The mounting plate 40 has a flat guide surface 68 formed parallel to and below the channels and openings in the first mounting portion 41. The flat guide surface 68 corresponds to the flat surface 63 formed on the bottom of the first enlarged area 37. Arm 2
When the 8 is guided into the mounting structure 32, the flat surface 63 is positioned on the flat guide surface 68 and the arm 28 is slid backwards. The two flat surfaces ensure that the arm 28 is properly aligned and smoothly guided into the mounting structure 32.

Both flat guide surface 63 and notch 56 can be illustrated in FIG. 4, which is slightly rotated relative to notch 56 from its actual position in FIG. The flat guide surface 63 extends from the rear end of the first enlarged area 37 towards the flange 70, which has the same outer dimensions as the rest of the first enlarged area 37. Flange 70 abuts lip 71 on mounting plate 40 when arm 28 is properly received within mounting structure 32.

Both the inner mounting member 35 and the outer mounting member 34 are preferably hollow, lightweight members and may include cables that provide electrical connection to the gripper handle 22. If so, a quick change electrical connector 72 can be connected between the electrical supply 73 and the mating connection in the arm 28. Bolt 74 is connector 7
2 is fixed to the mounting structure 32. Plug 76 is connector 7
2 forward and connected to a coupling plug in arm 28.
The electrical connector 78 extends radially outward of the first enlarged area 37 and can be coupled to an electrical sensor or other electrical device on the outer circumference of the arm 28.

Removing the arm 28 from the mounting structure 32 is illustrated in somewhat simplified form in FIGS. The inner mounting member 35 is secured to the rest of the arm 28 and is received within the mounting structure 32. In the mounted position shown in FIG. 5, spring 58 pivots latch member 52 into pivot hole 60 such that latch tooth 62 is received within notch 56.
Is biased around. The outward movement of the inner mounting member 35 is hindered by the latch member 52 because the latch teeth 62 are in contact with the flange 57. The set nut 48 is initially in the locked position, the upper surface 66 has been moved downwardly toward the lower surface 67, and the inner mounting member 35 is attached to the mounting structure 32.
It is locked inside.

When it is desired to remove the inner mounting member 35 from the mounting structure 32, the handle 50 is moved to the unlocked position 82, shown in phantom in FIG. Stop nut 4
8 moves on the bolt 68, allowing the upper surface 65 to move vertically upwards away from the lower surface 66. This releases the inner mounting member 35 from the mounting structure 32 by increasing the inner dimension of the second mounting portion 44. The latch teeth 62 remain in the notches 56 and allow the inner mounting member 35 to
Remain latched in the mounting structure 32.

As shown in FIG. 6, the force F is applied to the latch member 5.
2 to pivot the latch member 52 about the pivot hole 60 so that the latch tooth 62 disengages from the notch 56. The latch member 52 is at the latch position 8 shown in phantom.
It has been moved from 4 and is shown in the latch release position. When the latch teeth 62 are disengaged from the notches 56, the inner mounting member 35 is released from the mounting structure 32 as well as released from the latch.

As shown in FIG. 7, the inner mounting member 35 can then be moved axially forward until the recessed section 38 is aligned with the first mounting portion 41. The second enlarged area 47 is aligned with the intermediate open portion 46 and the inner mounting member 35 can be moved vertically upwards and removed from the mounting structure 32. The recessed area 38 is a flange 42
And between the openings defined by 43, the second enlarged area 47 passes upwardly through the open middle portion 46. During the first forward movement, the plug connection in arm 28 is removed from plug 76 in electrical connector 72.

The mounting plate 40 and the guide surfaces 63 and 68 are shown in FIG.
~ Not shown in Figure 7. However, when the arm 28 is removed from the mounting structure 32, the guide surface 63 becomes
It should be understood that the first movement of the arm 28 received on 8 is properly guided relative to the mounting structure 32.
In addition, the flat guide surfaces 63 extend a substantially greater axial distance than the guide surfaces 68 so that the guide surfaces rest on each other over most of the movement of the arm 28 relative to the mounting structure 32.

To remove the arm 28, it need only be moved forward of the mounting structure 32 by an axial distance approximately equal to the length of the first enlarged section 37, in the illustrated embodiment. , Which is about one-third of the total axial support distance. Prior art constructions may require the arm to move forward over the entire axial bearing distance. The present invention provides effective utilization of space near the mounting structure. By reducing the required travel distance, the frictional force that must be overcome to remove the arm 28 is greatly reduced. The arm 28 can be utilized for a variety of purposes and can be fitted with a multipurpose member such as a gripper handle 22.

When mounting arm 28 within mounting structure 32, the steps of FIGS. 5-7 are reversed. The recessed area 38 is aligned over the first mounting portion 41 and the second enlarged area 47.
Is received in the open middle portion 46. The arm 28 is moved downwards, the recessed area 38 passes into the opening in the first mounting portion 41 and the first enlarged area 37 passes into the channel in the mounting plate 40. The arm 28 is then moved backwards and the flat surface 63 follows the flat guide 68 until the flange 70 abuts the lip 71 and the second enlarged area 47 is received in the second mounting portion 44. Will be guided. During this rearward movement, the flange 47 contacts the latch member 52 and causes it to pivot against the force of the spring 58. Flange 57
As the spring moves past the latch teeth 62, the spring 58 pivots the latch member 52 in the opposite direction, causing the latch teeth 62 to move into the notches 56. The arm 28 is latched to the mounting structure 32. The handle 50 is then turned back from the unlocked position to the locked position and the arm 28 is locked to the mounting structure 32.

While the arm 28 is slid rearward, the flat guide surface 63 ensures that the arm is properly oriented with respect to the mounting structure 32 and the electrical connector 72. Plug 7
6 is properly aligned with the mating plug in arm 28 so that the necessary electrical connection is made quickly.

FIG. 8 is a side view of electrical connector 72 which includes a plug extending rearwardly of connector 70. The connecting portion 73 is received on the plug 80.

FIG. 9 is a front view of the electric connector 72.
The plug 76 is shown with a number of contact members that mate with corresponding members in the arm 28.

Although the present invention has been illustrated in combination with a work transfer assembly, its teachings apply to any application requiring attachment of an arm to a structure.

While a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention and are therefore intended to determine the true scope and content of this invention. The claims should be considered.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a work transfer assembly embodying a mounting structure of the present invention.

FIG. 2 is a perspective view of an arm and a mounting structure according to the present invention.

FIG. 3 is a partial cutaway view of the area indicated by arrow 3 in FIG.

FIG. 4 is an exploded view of the arm and the mounting structure shown in FIG.

FIG. 5 is a cross-sectional view illustrating a first step of removing the arm from the attachment structure of the present invention.

FIG. 6 is a diagram illustrating the subsequent steps of removing the arm from the mounting structure of the present invention.

FIG. 7 illustrates the final step of removing the arm from the mounting structure of the present invention.

FIG. 8 is a side view of an electrical connector according to the present invention.

9 is a front view of the electric connector shown in FIG.

[Explanation of symbols]

 20 Work Transmission Assembly 22 Grip Handle 24 Workpiece 28 Arm 30 Work Transmission Device 32 Mounting Structure 34 Tubular Outer Member 35 Inner Mounting Member 36 Clamp 37 First Enlarged Area 38 Intermediate Recessed Area 40 Mounting Plate 41 1st Mounting portion 42, 43, 70 flange 44 second mounting portion 46 intermediate open portion 47 second enlarged area 48 locking nut 52 latch member 56 notch 58 spring 60 pivot 62 latch tooth 63 guide surface 65 slot 66 upper surface 67 Lower surface 68 Bolt 71 Lip 72,78 Electric connector 73 Electric supply 76,80 Plug

Claims (22)

[Claims] 1. An arm extending from a front position to a rear position along an axis of the arm, the arm having a first outer dimension.
An enlarged area and a second recessed area of a second outer dimension, the second dimension being less than the first dimension, the recessed area being axial from the first enlarged area. A mounting structure extending along a mounting axis from a front position to a rear position and having an inner peripheral surface, the first mounting part comprising: Having an inner dimension that is approximately equal to a first outer dimension, the first enlarged area is received in a first mounting portion, and the inner peripheral surface extends through less than 360 degrees about the mounting axis. An access slot is defined as a 360 degree portion in which the inner peripheral surface does not extend, the access slot providing access to the inner peripheral surface of the first mounting portion, the access slot being The recessed area connects the access slot An attachment structure extending over a dimension greater than said second dimension for passage therethrough. 2. The assembly of claim 1, wherein the enlarged area and the recessed area have a generally cylindrical outer perimeter and the inner peripheral surface is generally cylindrical. 3. The mounting structure has a second mounting portion that is axially rearwardly spaced from the first mounting portion, and an intermediate portion of the mounting structure is between the first and second mounting portions. Spaced apart, the intermediate portion is open upward, the arm has a second enlarged area supported in the second mounting portion, and the recessed area has the first and second recessed areas. The assembly of claim 1 axially midway between the expansion zones. 4. The assembly of claim 3, wherein the access slot is formed in a vertical uppermost area of the first mounting portion. 5. The second enlarged area has a third outer dimension, the second mounting portion has an inner dimension approximately equal to the third dimension, and the third dimension has the third dimension. The assembly of claim 3 having a size greater than two. 6. The second mounting portion has spaced apart upper and lower surfaces defining a slot therebetween, the second mounting portion defining the second enlarged area within the second mounting portion. 4. The assembly of claim 3 which receives a bolt for moving the upper surface downwardly toward the lower surface for locking at. 7. The slot receives a latch member, the second enlarged area has a notch, the latch member is normally spring biased into the notch, and the latch member is about a pivot hole. 7. The assembly of claim 6, wherein said assembly is pivoted to and said bolt extends through said pivot hole. 8. The second enlarged area has a flange behind the notch, and movement of the second enlarged area forward of the second mounting portion causes the latch member to abut the flange. The assembly of claim 7, wherein the assembly is hindered by. 9. The assembly of claim 1, wherein a latch member is attached to the mounting structure and retains the arm in the mounting structure in a latched position. 10. The assembly of claim 9, wherein the latch member is spring biased into the arm. 11. The mounting structure has a flat guide surface,
The assembly of claim 1, wherein the first enlarged area has mating flat surfaces. 12. The mating flat surface on the first enlarged area terminates in a flange, the flange being a lip on the mounting structure when the arm is fully received within the mounting structure. The assembly of claim 11, which abuts against. 13. The assembly of claim 1, wherein the arm is hollow. 14. The assembly of claim 1, wherein said arm mounts a gripper handle of a work transfer assembly. 15. An electrical connector is attached to the mounting structure, the electrical connector is coupled to an electrical connection, the electrical connector has a plug, the arm has a mating plug, and the plug has the mounting structure. The assembly of claim 1 coupled to the arm from a location outside of the arm and providing an electrical connection. 16. The assembly of claim 15, wherein there is a device to ensure that the arms are properly aligned within the mounting structure and the plugs are properly aligned with each other. 17. A grip body handle for gripping a workpiece, a work transmission device for moving the grip body handle, an interconnecting connection between the grip body handle and the work transmission device, and along the axis of the arm. An arm extending from a front position to a rear position, the arm having a first enlarged area of a first outer dimension and a second recessed area of a second outer dimension, the second dimension Is smaller than the first dimension, the recessed area extends axially from the first enlarged area in an axial direction, and extends from the front position to the rear position along the attachment axis and A mounting structure having a first mounting portion for supporting, wherein the first mounting portion is the first mounting portion.
An inner dimension approximately equal to an outer dimension of the first mounting portion, the first mounting portion having an access slot to the inner dimension of the first mounting portion, the access slot having the recessed area defining the access slot. A work transfer assembly including a mounting structure extending over a dimension greater than said first dimension for passage therethrough. 18. The mounting structure includes a second mounting portion that is axially rearwardly spaced from the first mounting portion, and an intermediate portion disposed between the first and second mounting portions. 18. The intermediate portion is upwardly open, the arm has a second enlarged area, and the recessed area is axially intermediate the first and second enlarged areas. Work transfer assembly. 19. An electrical connector is attached to the mounting structure, the electrical connector is coupled to an electrical connection, the electrical connector has a plug, the arm has a mating plug, and the plug has the mounting structure. 18. The work transfer assembly of claim 17, wherein the work transfer assembly is coupled to the arm from a location outside of the arm and provides an electrical connection. 20. The work transfer assembly of claim 19 wherein there is a device that ensures that the arms are fitted within the mounting structure and that the plugs are properly aligned with each other. 21. An arm connected to an electric device and a mounting structure for mounting the arm, the mounting structure having an electrical connector at one end, the electrical connector corresponding to an electrical plug on the arm. A mounting structure having an electrical plug that allows the plug of the arm to be received in contact with the plug of the electrical connector to provide an electrical connection to the electrical device from outside the mounting structure. And a mounting structure for ensuring that the arms are properly oriented within the mounting structure and the plugs are properly oriented with respect to each other. 22. The device for ensuring that the arm is properly oriented within the mounting structure includes the arm and the mounting structure such that the arm is guided into the mounting structure in the proper orientation. 22. The mounting structure of claim 21, including flat guide surfaces disposed on both sides.