Patent GB-1394434-A (GB)
Title: Grinding machines and loading mechanisms therefor
IPC: B24B19/06
Filed: 1972-08-21
Abstract: 1394434 Grinding NEWALL ENG CO Ltd 24 Oct 1973 [21 Aug 1972] 38964/72 Heading B3D [Also in Division B8] A loading mechanism for a grinding machine comprises a magazine 11 which is arranged to deliver a series of components 33 to a loading station 34, a slidable component carrier 39 which is adapted to receive a component from the magazine at the loading station and to carry the component from the loading station to a grinding station 47, a rotary head 13 disposed at the grinding station, and a controllable magnet positioned for attracting a component from the carrier into engagement with the rotary head for rotation therewith. The machine has a grinding wheel 2 which is driven by a motor 3 and is dressed by a tool unit 7 on a traverse slide 6 movable along a feed slide 5 under the control of a pawl-and-ratchet drive mechanism 8. A carriage 20 is movable along slides 21 on a base member 22 by a pneumatic cylinder 16, and the base member is adjustable along a slide 24 on the machine frame 23 by a pawl-and-ratchet drive 26. The magazine is in the form of a pair of shoots provided by inclined grooves 11 in a plate 31, to which is secured a backing plate 32, for feeding a pair of components, such as the inner rings of bearings, to a pair of grinding stations. The plates extend into a chamber formed by the carriage 20 and slide 21, the components rolling down the grooves to loading stations 34 wherein, when, the carriage is in the retracted position shown in Fig. 3, air supplied through passages 35 transfers the lowermost components through bores 36 in plate 31 on to shoes 37, 38 adjustably mounted on a plate 39 which is adjustable about a pivot 40 on the carriage. The components may be held by small permanent magnets on the shoes 37, 38 and are sensed by magnetic switches 43 which disconnect the air supply to the passages 35 and actuate the pneumatic cylinder 16 to advance the carriage towards the grinding station. Microswitches are then actuated so that the electromagnetic face plate 46 of reach rotary head 13 is energized to hold the components while the heads are rotated by belt drive 50 from a continuously rotating D.C. motor 48, the components also being guided by further fixed shoes 51. During the advance of the carriage, the pin 40 engages a lever 52 to actuate a dashpot 54 which slows down the speed of the carriage as the shoes 37, 38 press the workpiece against the grinding wheel 2, the advance being terminated by stops 55 for spark-out determined by a timer 56. On retraction of the carriage, the current to the face plate is switched off and a lip 57 displaces the components from the shoes 51 so that they fall into a discharge shoot 14 and pass a demagnetizer 15 and a post-process gauging unit. After a number of grinding operations determined by a counter 60, the grinding wheel is dressed and the base member 22 is advanced a distance to compensate for wear of the grinding wheel. In another embodiment for loading one component at a time, the component may be transferred from a magazine in the form of a tubular member to the carriage by air pressure or gravity, the carriage acting on a gate so that only one component at a time is fed to the grinding station.