GB930947A - Apparatus for testing lip-seal units - Google Patents

Abstract

930,947. Locating magnetic bodies. GENERAL MOTORS CORPORATION. Feb. 12, 1962 [April 4, 1961], No. 5251/62. Class 37. [Also in Group XXVI] Apparatus for testing lip-seal units 28 for the presence of garter springs 32 comprises a seal unit support, a spring sensor head 59 movable to and from a seal unit when the unit is on the support, and a seal unit guide 82 movable, in response to signals from the sensor head, to determine the direction of travel of the units after testing. The apparatus is mounted on a plate 10 and includes a feed shoot 14, an exit shoot 78 for seals with garter springs and an exit shoot 80 for seals without garter springs. The sensor head 59 is mounted on the end of a shaft 55 adjustably secured to an arm 52 carried at one end 48 of the piston 50 of an air cylinder 46, a cam 60 being mounted on the other end of the piston. The seal unit 28 is supported by three pins 22, 24, 26 and clamped in position by a magnet 33 on the end of the piston 34 of an air cylinder 35. The guide 82 is pivoted at 84 and movable to either of the positions shown by the piston 86 of an air cylinder 88. The supply of air to the cylinders 35, 46 and 88 is controlled by electrically operable control valves. In operation, a seal unit 28 to be tested passes down the shoot 14 until it rests on the pins 22, 24, 26 and actuates a switch 36, Fig. 3; by contacting an arm 38 extending through the plate 10. Operation of the switch 36 causes air to be supplied first to the cylinder 35 and then, after actuation of a switch 62 by the cam 60, to the cylinder 46. The piston 34 is actuated to extend the magnet 33 into clamping engagement with the metal casing 29 of the unit 28 before the piston 50, whose movement is delayed by an air throttling device, brings the sensor head 59 into contact with the lip 31 of the unit 28 and causes the cam 60 to operate a switch 64 to complete an electric relay circuit for signals from the head. If a garter spring 32 is present the conductance of the head 59 is altered and a signal is passed which actuates the air supply to the cylinder 88 to hold the piston 86 and guide 82 in the position shown in Fig. 1. If the unit 28 is without a garter spring the signal from the bead 59 causes the piston to be retracted so that the guide is moved to the position indicated in dot-dash lines and the unacceptable seal is directed into the shoot 80. After an electrically predetermined time delay, the sensor head 59 and the magnet 33 are retracted by movement of the piston 50 and the piston 34 respectively. The seal unit 28 is carried with the magnet until the unit meets two pins 66 and 68 when it is disengaged from the magnet and passes into one or other of the shoots 78 or 80 according to the position of the guide 82.