GB984957A - Vacuum gripper - Google Patents

Abstract

984,957. Chucks. DUNHAM TOOL CO. Inc. Feb. 10, 1964, No. 5529/64. Headings B3B and B3D. A work-holding apparatus for holding a workpiece 13, Fig. 1, having an annular internal surface comprises a gripper body 10 having a generally annular surface which is adapted to mate with the internal surface of the workpiece and has circumferential groove means 21 therein, a vacuum actuated piston means 26, passage means 15, 18 connecting the groove means and piston means to a source of vacuum, and mechanical means 25 movable by the piston means to exert holding forces on the workpiece placed over the gripper body, the groove means being adapted to be sealed from the atmosphere by the workpiece to form a vacuum chamber accommodating the exertion of a holding force on the workpiece. upon connection of the passage means to a source of vacuum whereby the workpiece is held by a combination of mechanical and vacuum forces. As shown, the gripper body 10 has three grooves 21, 22, 23 which are connected by passages 18, 19, 20 to the passage 15 connectable to the vacuum source. The passage 15 also communicates with a recess 17 for a pin 26 which is secured to the mechanical means 25 in the form of a piston-like plate having a shoulder 27 for engagement with the internal wall of the workpiece and an O-ring 29 for sealing a vacuum chamber 31. In operation, the workpiece, which may be a rocket part, such as a nozzle skirt, is placed over the body and the plate applied over the end of the body, a knob 30 facilitating this operation. When vacuum is applied to the passage 15, it acts in the chamber 31 so that the plate 25 acts like a piston to press the workpiece on to the body 10 sealing the grooves from atmosphere to permit the vacuum to act in the grooves to also hold the workpiece on the body. In another embodiment for holding a workpiece 51, Fig. 2, in the form of a nozzle cone of a rocket, the gripper body 56 comprises an upper part 57 having a plurality of grooves 58 connected by passages 59 to a further passage 60 connectable to a vacuum source, and a lower part 55 in the form of a piston slidable in a cylindrical recess 71 in an upstanding part 54 mounted on a base 53. The lower portion of the upper part 57 and the lower part of the part 54 are formed with oppositely-inclined tapered surfaces 63, 64 which are engaged by a plurality of cylindrical segments 65 urged radially inward by a spring 66; a spring 72 also acts on the piston 55 to separate the surfaces 63, 64. The ends of the portion 57 have 0-rings 61, 62 for sealingly engaging the workpiece and surface of the body 56 so that when the vacuum source is connected to the passage 60, the workpiece is first held on the body by the vacuum forces in the grooves 58, the vacuum then acting in the chamber 71 to draw the piston 55 downwardly to move the tapered surface 63 towards the surface 64 so that the segments 65 are urged outwardly to grip the workpiece. The vacuum may be supplied to the base 53 of the chuck.