Patent GB-991841-A (GB)
Title: Automatic chamfering machine
IPC: B24B41/00
Filed: 1963-08-07
Abstract: 991,841. Grinding; machine tool details. BENDIX CORPORATION. Aug. 7, 1963 [Aug. 8, 1962], No. 31201/63. Heading B3B, B3D and B3K. A machine tool comprises a work supporting surface 28, Fig. 3, a stop means 76 against which a workpiece L is to be positioned, and a clamp member 78 which is reciprocably movable towards and away from the surface and has limited rotation about an axis 80, whereby it engages the workpiece between the axis and stop means before its clamping stroke is completed so that completion of the stroke causes the clamp member to rotate and thereby slide the workpiece against the stop means. The workpieces may comprise brake linings which are to have their ends chamfered, the work supporting surface 28 being formed on a member 62 mounted on an intermediate member 60 secured to a support member 50 which is rockable about a shaft 24 by a pneumatic motor 64 to present the end of the workpiece to a face of a grinding wheel 12 or other revolving tool having forwardly facing cutting edges; the members 60, 62 are replaceable with others of different size to accommodate various sizes of workpieces. The support member 50 carries an arm 52 which supports a pneumatic motor 86 having a rod 84 joined by a pin 80 to the clamping member 78. A weight on one end of the member rocks the latter to a position abutting a stop 88 so that, in its upper, inoperative position, the weighted end is nearer the work supporting surface than the other end. When the clamping member is lowered, the weighted end engages the workpiece and slides it along the supporting surface to a position abutting the stop 76, the completion of the stroke clamping the workpieee against the supporting surface. The shaft 24 about which the support member 51 rocks, is mounted in bearings in a carriage C which is adjustable along slideways 16 by a screw-and-nut arrangement 19, 20; the shaft 24 also carries abutments for actuating limit switches controlling the operation of the machine. The workpieces are fed to the supporting surface 28 from a magazine G, Fig. 4, having a roller conveyer part 34 leading to a vertical portion 36, 38 in which the workpieces are stacked one upon another on a loading surface 30. A pusher 32 is connected to the rod 48 of a pneumatic motor 40 and is operable to slide the lowermost workpiece along the surface 30 to the work supporting surface 28. In operation, when a start button is pressed, a solenoid-operated valve 100, Fig. 7, is actuated to cause the motor 40 to advance the pusher 32 at a speed controlled by a throttle 106 to feed a workpiece to the supporting surface until a limit switch LSI is operated to reverse the motor which retracts the pusher at a fast speed and actuates a limit switch to cause a solenoidoperated valve 124 to cause the motor 86 to lower the clamping member 78 to position and clamp the workpiece. Simultaneously, a solenoid-operated valve 112 is actuated to cause the motor 64 to rock the support member 51, the motor being controlled by valves 114, 116 and limit switches so that the workpiece is first advanced at a rapid speed and then at a slow speed to a forward position in which the end of the workpiece is chamfered by the wheel, abutments 90, 122 extending from the shaft 24 and limit switches LS-3 and LS-4 controlling the change of speed and reversal of the motor 64 and motor 86 so that the workpiece is unclamped when the work support reaches its initial position and abutment 90 again actuates switch LS-2 and the motor 40 is again operated to feed a new workpiece to the supporting surface. The control circuit has provision for manual operation of the machine. The positions of the limit switches are adjustable to adapt the machine for different sizes of workpieces. The grinding wheel may be dressed by a tool 170, Fig. 1, which is mounted on a cross-slide 172 traversable by a hand wheel 180, the cross-slide being adjustable axially of the wheel by a lead screw and hand wheel 178. The screw-and-nut arrangement 18, 20, in addition to adjusting the depth of chamfer, adjusts the carriage C for wear of the grinding wheel. The machine may be used to chamfer workpieces other than brake lining, to contour the ends of workpieces and to machine workpieces to predetermined lengths. In other embodiments, the motors are in the form of hydraulic cylinders, electrical solenoids, or gear trains.