Patent GB-1018060-A (GB)
Title: Method and apparatus for holding workpieces for a material removal operation
Inventor: BELL RAMSAY MOYER
IPC: B24B41/06
Filed: 1964-11-17
Abstract: 1,018,060. Grinding. HAMMOND MACHINERY BUILDERS, Inc. Nov. 17, 1964, No. 46830/64. Heading B3D. A method of holding a sharply bent, elongated workpiece W, Figs. 1 and 4 (not shown), such as an automotive window frame, in position for engagement by a tool 17, such as a grinding wheel, buffing wheel or abrasive belt, comprises loosely supporting-the workpiece substantially at the zone A where it is bent so that portions W L , W R  on each side of the zone hang downwardly and are maintained in such position by gravity but are free to swing about the support position, applying a clamping force to a first position on the workpiece spaced from the zone, and resisting the clamping force at a second position spaced from the zone, whereby the workpiece is rigidly supported at three positions when the clamping force is applied. In apparatus for carrying out the method, a number of work stations 1 to 6 are provided through which workpieces are passed in a stepwise manner. The support for the bent zone A of the workpiece consists of a hollow beam 1 which extends through the stations and is supported on pedestals 2. A pair of rub bars 6 are mounted on the upper part and a drive bar 7 is reciprocatable in the beam by a fluid-pressure device 9 and has retractable lugs 8, Fig. 2 (not shown), which in one direction of movement of the bar move the workpieces W along the beam and in the other direction are retracted against the force of a light spring 10. An abutment bar 31 extends along one side of some of the stations for engagement by the portions W L  of the workpieces when the portions W R  are engaged by the clamping means which consist of pads on the rods of fluid pressure devices 34 mounted on the frame 23 of the apparatus. At station 1, a workpiece is placed in the beam and is moved therealong by a lug 8 on the beam until it engages a stop 11 at the station 2 which has an abrading device 16 comprising a grinding wheel 17 mounted on a yoke 18 movable along a slide 19 by a fluid pressure device 25, the slide being movable about a pivot 21 by a fluid pressure device 26 to engage the grinding wheel with the workpiece. After operation at station 2, the stop 11 can be retracted by a fluid pressure device 12 to enable the workpieee to be moved by the lugs 8 on beam 7 to the next station 3 for further operation by another abrading device. If the workpiece has two bent zones A, B, Fig. 6 (not shown), during its movement from station 3 to station 4 by the lugs 8 on the bar 7, a cam 42 having ends 42a, 42b engages the workpieee to rotate it about the bent zone A so that it slides to a position in which the zone B is supported by the beam 1. When the workpieee is then moved to station 5, a clamping device engages a portion of the workpiece one side of the zone B to urge a portion the other side of the zone against an abutment 31a which extends through the next station 6, stations 5 and 6 having abrading devices similar to those in stations 2 and 3. In another embodiment, the movement of zone B of the workpiece on to the beam 1 is effected by a fluid-pressure cylinder 51, Fig. 11 (not shown), having a shoe 52 for engaging the workpiece, a cam 50 being engaged by the workpiece as it moves. In a further embodiment, Figs. 14 and 15 (not shown), work supports 84, 85, 86 at the stations are mounted on stands 81, 82, 83 and provided with slots 91 for a bar 92 which is reciprocable by a rod 99 connected to a disc 98 and is movable vertically by cams 103, 104, 105 driven by a shaft 108 in timed relation to the reciprocation by the rod 99. In operation, a workpiece is placed against a stop 95 on the support 84 and the bar is raised by the cams and moved by the rod 99 and disc 98 to carry the workpiece to the support 85 when it is clamped as described above for an abrading operation after which it is moved to the next support for a further clamping and abrading operation. In yet a further embodiment, the workpieces are carried from station to station by supports mounted on an endless conveyer belt. In an embodiment for operating on a single bent workpiece, the latter is supported by its bent zone on rails 113, 114, Fig. 18 (not shown), and has a portion engaging a fixed abutment 116. The workpiece is held against the rails and abutment by a clamp 117 acting between the abutment and the rails.