GB1397107A - Grinding machines - Google Patents

Abstract

1397107 Grinding; chucks NEWALL ENG CO Ltd and S W HOARE 25 June 1973 [10 May 1972] 21930/72 Headings B3D and B3B A machine for grinding the external surface of a tubed or like elongate member comprises a workhead 13, Fig. 1, including a rotatable hollow spindle 14 and means for intermittently clamping the member for rotation with the spindle, grinding means 16, a feed mechansim 12 for intermittently traversing the member through the hollow spindle and past the grinding means, and indexing means for halting the motion of the member past the grinding means at predetermined intervals. In one embodiment, the member is in the form of a coil of tubing 1 on a drum 2 freely rotatable about a spindle 3 carried by a bracket 4 from a plate 5 on a shaft 6 belt-driven from a motor 8, the axis of the shaft 6 being tangential to the drum. From the drum the tubing is drawn by the feed mechanism 12 through a straightening device 9 having two sets of rollers 10, 11 and fed intermittently to the chuck 14 of the workhead 13. The end of the tubing extends from the chuck and is supported by steadys 20, 24 for grinding by a profiled wheel 16, which is supported for transverse movement along a slideway 17 and is dressed by a roller 19, and for severing by a cut-off wheel 21 driven by a motor 22 movable along a guideway 23. In another embodiment, a series of bars 33, Figs. 2 and 3, are fed by means of a hopper 30 to the chuck 14 and past the grinding wheel to positions determined by an indexing lever 31. The hopper has an inclined support 32, a lower fixed part 35, and a series of movable upper parts 36 each of which is movable by an arm 37 rockable about a pivot 38. The lowest bar on the supports rests against an abutment 40 and when the upper parts 36 are raised, fingers 39 are rotated about a pivot 41 to push the lowest bar over the abutment into the fixed part 35. A link element 42 limits the movement of the fingers 39. The fingers 39 and overhead bar supports 45 are adjustable for differing diameters of bars. The bar resting in the fixed part 35 is moved towards the chuck 14 by a pusher bar driven by a chain 50 in a housing 51. The distance the bar is pushed at each step is determined by an indexing deice 31, Fig. 5, consisting of a lever 90 which is pivotable about an axis 91 and has a series of stops 92, 93, 94 which can be brought selectively into alignment with the path of the bar. The lever is biased into the position shown by a spring 95 so as to engage a stop 98 and is indexed to bring the stops 92, 93 into alignment with the bar by a pneumatic cylinder 100, the positions of the lever being determined by resiliently biased rollers 102, 103, 104 engaging respective notches 105, 106, 107 in a wheel 101. The stop 92 is only operative to position the front end of a new bar. Thereafter, the stops 93 and 94 are alternately operative to position the bar for grinding by wheel 16 and cutting by wheel 21. The workhead 13 consists of a spindle 60, Fig. 4, driven by a belt 61 and has a bore 62 for receiving the bar workpiece 64. A collet 63 in the chuck 14 grips the tail end of the workpiece for withdrawal thereof on completion of the grinding operations, the collet being connected to the drive chain 50 of the hopper. A collar 65 is fixed in the workhead and has bearings for rotatably supporting the spindle 60. A passage 68 is selectively connectible to a high pressure source of fluid and is connected by an annular chamber 69, axial passages 70, and bores 71 in an end cover of the chuck to a space 74 to move an element 75 against springs 77 so as to release the pressure of a tapered part 80 from jaws 81 gripping the workpiece to permit the intermittent advance thereof.