Article Gripper Mounting Device

The invention concerns multi-axis manipulators and more particularly a mounting device for supporting the article gripper portion of a multi-axis manipulator in a manner that allows the latter to have an additional degree of freedom so that the manipulator can be used for inserting and removing articles from a stationary member along a straight line located in a substantially vertical plane.

In the preferred form, the article gripper mounting device according to the invention is combined with the wrist assembly located at the end of the support arm of a multi-axis manipulator. The wrist assembly has a gear unit that serves to pivot a carrier about a horizontal axis and rotates an output shaft about an axis lying in a vertical plane passing through the longitudinal axis of the support arm. More specifically, the article gripper mounting device includes a ring member which is adapted to be rigidly secured to the carrier so as to provide a circular track located concentrically with respect to the axis of the output shaft and in a plane perpendicular thereto. A support member is adapted to be secured to the output shaft and has a plurality of circumferentially spaced rollers supported for movement along the circular track of the ring member. The support member is provided with bearing means for slidably supporting a pair of parallel guide rods which form a part of a movable carriage. An actuator is connected between the support member and the carriage for moving the latter between two extreme positions and the carriage is formed with suitable means for carrying the article gripper.

The objects of this invention are to provide a new and improved article gripper mounting device for a multi-axis manipulator that permits the article gripper to move along a straight line that is parallel to the longitudinal axis of the gripper member without requiring concurrent movement of the manipulator's supporting arm; to provide a new and improved article gripper mounting device that is attachable to the wrist assembly of a multi-axis manipulator to provide an additional degree of movement for the article gripper; and to provide a new and improved mounting device for an article gripper that is adapted to be combined with the wrist assembly of a multi-axis manipulator to allow the latter to be used for accurately inserting components into another member along a straight line located in a substantially vertical plane.

A more complete understanding of the invention will be derived from the following detailed description when taken with the drawings in which:

FIG. 1 is a perspective view showing a multi-axis manipulator equipped with an article gripper mounting device according to the invention;

FIG. 2 is an enlarged elevational view taken on line 2--2 of FIG. 1 showing the article gripper mounting device with some parts broken away;

FIG. 3 is a side elevational view of the article gripper mounting device taken on line 3--3 of FIG. 2;

FIG. 4 is a plane view of the article gripper mounting device taken on line 4--4 of FIG. 3; and

FIG. 5 is a side elevational view showing a modified form of the article gripper mounting device of FIGS. 1-4.

Referring to the drawings and more particularly FIG. 1 thereof, a multi-axis manipulator 10 is shown which is suitable for programmed control movement to achieve universal work processing relationship with respect to parts such as the support stand 12. The manipulator 10 comprises an elongated support arm 13 which has the rear end thereof mounted on a pedestal type base 14 that extends into a housing 16. The housing 16 includes the usual controls for automatically causing the work end of the manipulator 10 to move along various axes under the control of a program. Inasmuch as the controls form no part of the present invention, further description will proceed with reference to the mechanical parts of the manipulator 10 that provides the requisite movement of an article gripper 18 which is supported by a mounting device 20 made according to the invention.

The support arm 13 includes a pair of axially movable tubular member 22 and 24 which terminate at their outer ends with a wrist assembly 26, which in turn, supports the mounting device 20. Both tubular members 22 and 24 are concurrently movable by a suitable drive unit (not shown) along the rectilinear path indicated by reference numeral 28. The wrist assembly 26 includes a gear unit which serves to rotate the mounting device 20 along a first circular path 30 and along a second circular path 32. In addition, the rearward end of the arm is pivotally supported on the base 14 so as to provide pivotal movement of the entire arm member about a horizontal axis along a circular path 34. The base 14 is also rotatable about a vertical axis along a circular path 36 so that the entire support arm 13 can swing in an arc and position the article gripper 18 at different locations.

Thus, it should be apparent from the above description that the manipulator 10 has five degrees of freedom which permits the machine to perform various material handling operations. It will be noted, however, that in this case, the mounting device 20 allows the manipulator 10 to have an additional degree of freedom, namely, movement along a straight line path 38 located in a plane that passes through the longitudinal axis of the arm member 13. This additional degree of freedom allows the article gripper 18 to move along the path 38 downwardly to remove a cylindrical member 40 located within an opening provided in the supporting stand 12. In this regard, it will be noted that the article gripper 18 is of a conventional type having a pair of pivoted jaws 42 and 44 which are movable towards and away from each other when commanded to do so by the control system of the manipulator 10. Thus, as seen in FIG. 1, the jaws 42 and 44 of the article gripper 18 are in the open-position and will remain in this position until the mounting device 20 moves the article gripper 18 downwardly to a point where they are located adjacent to and on diametrically opposed sides of the cylindrical member 40 whereupon the control system, when so programmed, will cause the jaws 42 and 44 to move towards each other into engagement with the outer surface of the cylindrical member 40. The article gripper 18 is then moved upwardly by the mounting device 20 while holding the cylindrical member 40 and the latter is deposited at another point as required by the programmed control system.

Referring now to FIGS. 2, 3 and 4, the mounting device 20 comprises a spider-like support member 46 which is rigidly connected with an output shaft 48 and rotatably carries six rollers 50, 52, 54, 56, 58, and 60. The rollers 50, 54, 56 and 60 are located on the front side of and move along a circular track provided by a ring member 62. The ring member 62 is secured to a carrier 63 having a pair of laterally spaced arms 64 and 66 pivotally mounted on shafts 68 and 70 which are part of the wrist assembly 26. The rollers 52 and 58 are located on the rear side of the ring member 62 which also provides a circular track along which the latter mentioned rollers can travel. It will be noted that the ring member 62 is concentrically located relative to the rotational axis of the output shaft 48 so that upon rotation of the latter, the support member 46 is guided for similar rotation by the rollers as they move along the circular track on the opposed sides of the ring member 62.

A gear unit is provided within the wrist assembly 26 for rotating the output shaft 48 and thereby causing the mounting device 20 to rotate as a unit in the circular path 32 shown in FIG. 1. The same gear unit also causes the mounting device 20 to rotate along the path 30, and as seen in FIG. 4, the gear unit of interest comprises a pair of identical bevel gears 72 and 74 which are supported for rotation within the tubular members 22 and 24 respectively of the arm member 13. The gear 74 meshes with a bevel gear 76 which is fixed to the shaft 70 the inner end of which rigidly carries a bevel gear 78 that is of the same size as the gear 76. The gear 78 meshes with a bevel gear 80 which is fixed to the output shaft 48. Thus, by rotatably driving gear 74, the gear 78 is rotated to provide rotating movement of the output shaft 48 and accordingly the support member 46 along circular path 32. As to realizing rotation of the support member 46 along path 30, it will be noted that the gear 72 meshes with a bevel gear 82 secured to shaft 68, which in turn, is fixed with the housing 86 of the wrist assembly 26. The housing 86 forms a part of the carrier 63 so that upon rotatably driving both gears 72 and 74 simultaneously in the same direction, the carrier 63 is rotated in the path 30 so that the mounting device 20 is pivoted about a horizontal axis passing through the shafts 68 and 70.

As seen in FIG. 2, the support member 46 rigidly supports a pair of laterally spaced housings 88 and 90 each of which is provided with a pair of axially aligned cylindrical bushings 92 and 94. The housings 88 and 90 serve to slidably support a pair of guide rods 96 and 98, respectively, the outer ends of which are fixedly connected to a carriage 100. The carriage 100 consists of a rectangular frame composed of side bars 102 and 104, a top bar 106, and a bottom bar 108. The latter two bars are rigidly secured to the outer ends of the guide rods 96 and 98. The frame has a frontal plate 110 fixed thereto that supports a bracket 112, which in turn, carries the article gripper 18 as seen in FIG. 3. Between the housings 88 and 90, an interconnecting bar 113 is provided that serves as a base for one end of a double rod-ended air cylinder 114. The air cylinder 114 consists of the usual cylinder portion the lower end of which is fixed to the support member 46 through the bar 113 and has the piston rod thereof extending through an opening 116 in the bar 113 for threaded connection with the bottom bar 108 of the carriage 100. Thus, by directing pressurized air to the upper end of the air cylinder 114 through an air line 118, the carriage 100 is movable along the path 38 from the full position shown in FIG. 1 to the dotted line position. Similarly by directing pressurized air to the lower end of the air cylinder 114 through the air line 119, the carriage 100 is movable along a straight line from the dotted line position to the full line position. Thus, once the mounting device 20 is properly oriented above the stand 12 relative to the cylindrical member 40, no further movement of the support arm 13 or of the wrist assembly 26 is required for the removal or the insertion of the cylindrical member 40 except the actuation of the air cylinder 114 and the article gripper 18.

FIG. 5 shows a modified form of the invention, and it will be noted that parts thereof corresponding to the parts of the manipulator 10 and mounting device 20 shown in FIG. 1-4 are identified by the same numerals but primed. In this case, in addition to providing the straight line movement of the article gripper 18', the modified mounting device identified by reference numeral 200 also allows the article gripper 18' to rotate about its longitudinal center axis. Thus, an additional degree of freedom is provided for the manipulator 10 so that the article gripper 18' is movable along seven axes. This seventh degree of freedom is realized by having the article gripper 18' rotatably supported within a housing 120, which in turn, is fixed to a bracket 122 secured to the carriage 100'. It will be noted that the article gripper 18' has its upper end connected to a shaft 124 that is rotatably carried by a pair of bearing assemblies 126 and 128 located within the housing 120. The upper end of the shaft 124 extends through a gear housing 129 and is splined to a gear 130 in a manner that allows axial movement of the upper end of the shaft relative to the gear 130 maintaining a rotary drive connection therewith. The gear 130 meshes with a gear 132 rotatably driven by a telescoping rotary drive 134 the upper end of which has a joint 136 that is universally pivotable about mutually perpendicular axes. The lower end of the drive 134 similarly has a joint 138 that is supported for universal pivotal movement about mutually perpendicular axes. The drive 134 is connected to an output shaft 140 supported by the arm member 13' of the manipulator. Accordingly, in this instance the wrist assembly 26' will provide rotational movement of the mounting device 200 about the circular paths 30 and 32, as seen in FIG. 1, while the air cylinder 114' will permit the carriage 100' and the attached article gripper to move along a straight line along path 38. In addition, the gear 130 when rotatably driven in one direction of the other by the gear 132 will cause the article gripper 18' to be rotated in a similar direction about its longitudinal center axis.

Various changes and modifications can be made in this construction without departing from the spirit of the invention. Such changes and modifications are contemplated by the inventor and he does not wish to be limited except by the scope of the appended claims.