Patent GB-920257-A (GB)
Title: Work indexing means for disc grinders
Inventor: PRICE RALPH ELDRIDGE
IPC: B24B7/16
Filed: 1959-06-23
Abstract: 920,257. Grinding. GARDNER MACHINE CO. June 23, 1959, No. 21405/59. Class 60. A disc grinder for grinding pairs of parallel faces of a workpiece comprises rotatable abrasive discs having opposed operative surfaces, a rotatable work carrier having peripherally spaced work holders for carrying workpieces between the discs, means for transferring a partly finished workpiece from the work carrier to an indexer, means associated with the indexer for reorientating a workpiece thereon for subsequent grinding of a second pair of parallel faces, and means for returning a reorientated workpiece from the indexer to the work carrier. A machine comprises opposed rotatable abrasive discs 17, 18 and a rotatable work carrier 10 having around its periphery workholding fixtures 11 each having notches for receiving a workpiece 13, e.g. a universal joint spider. The workpieces are held in the fixtures by a belt 14. Means for indexing the workpieces to present a second pair of parallel faces for grinding consists of a rotatable member 20 having around its periphery work-holding fixtures. Each of these consists of a rotatable member 25 having notches for receiving a workpiece and having an integral stub shaft 27 journalled on a support member 28. An index wheel 30 attached by a pin 31 to a reduced portion 29 of the stub-shaft 27 co-operates with a spherical member 40 supported on a bracket 41. A ball 35 urged by a spring 36 into a depression 37 in the underside of member 25 locates the latter for proper alignment of a workpiece in the indexed position for transfer back into a fixture 11 of the work carrier 10. Transfer of the workpieces from the work carrier 10 to the member 20 and vice versa is effected by axially spaced members 50 having control fingers 51 for engaging each of a pair of axially spaced journals in a workpiece. On either side of the fingers and spaced therefrom are guide portions 54, 55. Members 50 are pivotally mounted at 52 on spaced support members 56, 57 and are urged in a clockwise direction by a spring 53. Discharge of finished work pieces from the work carrier 10 and retention cf halfground workpieces in the work carrier for transfer to the member 20 is effected by a pair of fingers 60 pivotally mounted in the support members 56, 57 and urged in a counterclockwise direction by a spring 61. The member 20 is driven through gearing by a motor 70 and drives the work carrier 10 through a chain 72. A limit switch LS1 mounted on a bracket 75 in position to engage a series of pads 76 angularly. spaced about one side of the carrier 10 is connected in series with a pair of gauge contacts 77 located so as to be contacted by a workpiece after it has passed through the grinding zone, the disposition of parts being such that when the workpiece is passing through the gauge the limit switch is actuated by one of the pads and the gauge circuit is operative only at this time. The gauge contacts may be used to measure overall width and give a visual signal for information of the operator or may be used to provide separate signals to adjust the corresponding grinding discs. A limit switch LS2 mounted on the bracket 75 has an arm resting on a projection 81 on a work-engaging shoe 82 pivotally mounted on the bracket and held against a workpiece by a spring, so that so long as there is a workpiece in each work-holding fixture the switch will be closed. If an empty work-holding fixture 11 attempts to pass the shoe 82, the switch will open and break the circuit to motor 70. In the cover 100 is mounted a limit switch LS3 to which is hinged a feeler member 101 resting upon a ledge inside the cover and including an adjustable bar having a pair of fingers 102 spaced to coincide with the journals on a workpiece. If the workpiece is not solidly positioned in the work-holding fixture, it will engage fingers 102 and actuate limit switch LS3 to break the circuit to motor 70. Switches LS2, LS3 are in series so that both must be closed to keep motor 70 in operation.