Patent Number: 051903334
Section: description

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to FIG. 1, there is illustrated a linkage in one environment of use. The linkage, indicated by the reference numeral 10 is attached to a tube 12 that serves as a frame to which linkage 10 can be mounted and positioned in the general vicinity of need. Depending from linkage 10 is an end effector, such as a gripper 14. Within tube 12 is an actuator such as an air cylinder 20 with an air hose 22 and a shaft or rod 24 moved by the injection of and release of air from air cylinder 20. Adjacent to air cylinder 20, on one side is stationary bracket 26; on the other side is a stopping bracket 28, the functions of which will be explained presently. Gripper 14 is illustrated as being operated by its own air cylinder 36 supplied by a separate air hose 38. However, other end effectors manipulated by other means may be deployed by linkage 10 equivalently. Linkage 10 has three links: a first link 44, a second link 46, and a third link 48. First link 44 has a first end 52 and a second end 54. Second link 46 has a first end 58 and a second end 60. Third link 48 has a first end 64 and a second end 66. As will be seen by comparing FIGS. 1 and 3, each link is doubled, in the preferred embodiment, for equalization of forces and stresses. First end 52 of first link 44 is pivotally attached to a bar 70 that is attached to rod 24. Second end 54 of first link 44 is pivotally attached to second link 46 at a point 72 between first end 58 and second end 60 of second link 46. First end 58 of second link 46 is pivotally attached to a stop 74 on the end of stopping bracket 28. Second end 60 of second link 46 is pivotally attached to the side of gripper 14 at 76. First end 64 of third link 48 is pivotally attached to stationary bracket 26, and second end 66 of third link 48 is pivotally attached to the end of gripper 14 at 78. When linkage 10 is holding gripper 14 in line with an axis 82, the arrangement presents a compact, small diameter device, suitable for inserting in narrow channels. In FIGS. 2 and 4, however, gripper 14 has been rotated about a second axis 84 perpendicular to axis 82 to invert gripper 14. The inversion is achieved by the pulling of rod 24 which in turn pulls first link 44. First link 44 pulls at 72 on second link 46 causing it to rotate about its first end 58. Third link 48 moves with gripper 14 and acts to prevent gripper 14 from swinging about second end 60 of second link 46 at 76 where it meets gripper 14. Third link 48 therefore serves a stabilizing function. Second link 46 affects the amount and direction of rotation of gripper 14. Second link 46 has a right angle bend as illustrated which divides the 180.degree. required for the inversion into two 90.degree. portions. The first portion is achieved by first end 58 of second link 46 as it moves from engagement with a first face 92 of stop 74 to a second face 94 90.degree. from first face 92. Meanwhile, second end 60 of second link 46 pivots with respect to side 76 from parallel to perpendicular to complete the inversion. It will be apparent to those skilled in the art that many changes and substitutions can be made to the preferred embodiment herein described without departing from the spirit and scope of the present invention. For example, the inversion does not have to be 180.degree. but can be less or a little more depending on such factors as the angle between first and second faces 92, 94 and the length of first link 44. The end effector can be a gripper, as referred to in the present description, or some other tool or manipulator or operative device such as a welding torch. Similarly, air cylinder 20 could be replaced by an hydraulic cylinder or electro-mechanical device, so long as it is capable of controlled motion of rod 24. The invention is, therefore, to be defined by the appended claims.