Patent GB-1155631-A (GB)
Title: Improvements in and relating to Machine Tools for Machining Workpieces having Annular Flanges
IPC: B24B41/06
Filed: 1966-06-22
Abstract: 1,155,631. Grinding. LANDIS TOOL CO. 22 June, 1966 [24 June, 1965], No. 27826/66. Heading B3D. A machine tool for machining a workpiece having an annular flange comprises a cutting tool and means for effecting axial location of a workpiece relative to such cutting tool including an axially movable locating device having a plurality of locating members for engaging the flange of the workpiece and moving the workpiece axially, holding means for holding the workpiece firmly in axial engagement with the locating device at least during engagement of the locating members and workpiece and positive stop means for stopping the axial movement of the locating device. A machine for face grinding the opposite ends 18, 19 of a workpiece 16 having a cylindrical bore 23, a tapered outer surface 22 and a flange 20 includes opposed grinding discs 12, 13 rotatable by motors MTR1, MTR2 and movable towards and away from one another by mechanisms 116, 117 controlled by a valve 115 shifted by a solenoid M. The machine includes a chuck 24 of the pressure expanding type carried by a shaft 25 mounted in a bearing structure 26 carried by a support element 27. The shaft 25 is rotated, through belts 31, by a motor MTR7 on the support element. The shaft 25 has a bore 32 in which is a pressure exerting piston 34 carried by a control rod 33 which is part of a fluid motor 107 mounted within the shaft 25, a rotary union 35 being provided on the end of the shaft; the fluid motor is controlled by a valve 106 shifted by solenoids E, F. The support element 27 is mounted for pivotal movement about a shaft 28, movement being effected by a fluid motor 111 controlled by a valve 110 shifted by solenoids H, J. A workpiece is positioned on the chuck by a locator 36 carried by a shaft 37 mounted in a housing 38 for axial reciprocation effected by a fluid motor 39 controlled by a valve 105 shifted by a solenoid D. The locator comprises a plate 40 secured to the shaft 37 and a plate 41 removably secured to the plate 40. The face of the plate 41 has three radial grooves 42, each receiving the base 43 of a finger 44 secured by a screw 45. Pins 48 in the plate 41 project into sockets 49 in the bases 43 and are engaged by adjusting screws 50 for radial location of the fingers 44. Each finger 44 has a portion 51, integral with the base 43, and a portion 52 connected thereto by a resilient strap 53; the portion 52 has a recess 55 to facilitate relative pivoting of the portions. Each portion 52 carries a carbide ball 56 for simultaneous engagement with the outer surface 22 of the workpiece and the face 21 of the flange 20 thereon. Each portion 52 carries a screw 96 the screw head 97 projecting beyond the ball 56. A plate 58 secured to the locator shaft 37 carries a stop 59 co-operating with a stop 60 on the housing 38 for axial positioning of the locator relative to the chuck 24 when the locator is advanced, one of the stops being adjustable. A workpiece supply mechanism 61 includes an upstanding plate 62 carried by the machine frame 11 and having an extension 63 to which is attached a guide 64 associated with an escapement 65 for periodically releasing one workpiece at a time; operation of the escapement is controlled by a valve 114 shifted by a solenoid K. An indexing turret comprises a plate 66 on a shaft 67 driven, through an indexing unit 74, by a motor 73. The plate 66 has work-receiving notches 68 and is spaced from the plate 62 by such a distance that the flange 20 on a workpiece remains confined between the plates 62, 66 so that the workpiece is located axially. A guide 69 prevents radial movement of workpieces out of the plate 66; the guide 69 is extended below the plate 66 to form a discharge shoot 70; an upright guide 71 co-operates with the plate 62 to retain a workpiece in the discharge shoot. The plate 62 has a large opening 72 for axial passage of a workpiece, thus permitting removal of a workpieee from a pocket 68 by the locator 36 and later repositioning of the workpiece within the same packet 68. The pockets 68 are shaped so as to accurately control the position of each workpieee at the time it is engaged by the locator 36 and each pocket has a notch 98 to clear a finger of the locator 36. A stripper 75 concentric with the chuck shaft 25 is carried by rods 76 slidable in bearings 78 carried by enlargements 79 at opposite ends of the bearing structure 26. The stripper includes a front plate 82 having sockets 83 containing balls 84 biased outwardly by spring plates 85. The stripper is moved axially by a fluid motor 88 controlled by a valve 108 shifted by a solenoid G. The motor is coupled to a plate 89 mounted on the rods 76 and carrying a stop 90 engageable with an adjustable stop 91 carried by one of the projections 79 to limit the advance of the stripper. The first function of the stripper is the removal of ground workpieces from the chuck. Its second function is to facilitate positioning of the locator 36 with respect to a workpiece. When the stripper has advanced it is positioned within the opening 72 in the plate 62; as the plate 82 does not project beyond the plate 62, it does interfere with indexing of the plate 66. In this position the stripper functions as a back-up for the workpiece, holding it against movement when it is being engaged by the locator 36. The workpiece directly engages the balls 84 when the locator seats against the workpiece so that the impact of the seating operation is absorbed by the balls 84 which are substantially aligned with the locator balls 56. In the absence of a workpiece the locator screw heads 97 engage the stripper to prevent direct contact of the balls 56 therewith to minimize wear or physical damage of the balls. After a workpiece has been clamped on the chuck and the locator and stripper retracted, the chuck with the workpiece is swung in between the grinding discs 12, 13 by pivotal movement of the support element 27. Operation.-In the " at rest " position of the machine, stripper 75 is in its advanced position. (1) Switch " START HYDR. PUMP " is closed, energizing motor MTR3 driving hydraulic pump 100 and energizing the remainder of the electrical system; (2) START switches 101, 102 are closed, energizing motors MTR1, MTR2, thus rotating grinding discs 12, 13; (3) Cycle START switch 103 is closed; (4) Index switch 164 is closed, causing the turret to index to present a workpiece between locator 36 and chuck 24; (5) On completion of indexing, switch 104 opens, energizing solenoid D, thus advancing locator 36 which engages the workpiece positioned by the turret and backed up by stripper 75 so that the workpiece will be fully seated within locator 36. Further advance of the locator pushes stripper 75 back against the relatively light resistance of the fluid motor 88; (6) Locator 36 advances until stops 59, 60 engage, the workpiece carried by the locator being then accurately positioned in telescoped relation to chuck 24; at this time switch LS5 closes, energizing timer 3TR, thus energizing solenoid E and de-energizing solenoid F, resulting in pressurization of chuck 24 to clamp the workpiece carried by locator 36 in the position determined by the locator; (7) Pressure switch 2PS closes energizing timer 12TR, thus (a) de-energizing solenoid G to retract stripper 75 and (b) de-energizing solenoid D to retract locator 36; (8) Switches LS2, LS3 close (a) de-energizing solenoid H and energizing solenoid J to swing support element 27 towards the grinding discs, (b) energizing motor MTR7 to rotate chuck 24, and (c) energizing solenoid K, so actuating escapement 65 to release one workpiece and permit it to move into the open uppermost notch 68 of the turret; (9) Switch 10LS opens, followed by closure of switch 9LS, thus (a) de-energizing solenoid K, and (b) energizing solenoid M to advance grinding discs 12, 13 into opposite ends of the workpiece; (10) When the desired grinding is effected (a) gauge switch 118 opens, de-energizing solenoid M to retract grinding discs 12, 13 and (b) gauge switch 119 closes, de-energizing solenoid J and energizing solenoid H, to return support element 27 to its original position; (11) Switch 9LS opens, de-energizing motor MTR7 to stop rotation of the chuck; (12) When chuck 24 is in alignment with the locator, switch 10LS closes, de-energizing timer 3TR, de-energizing solenoid E and energizing solenoid F, to release chuck 24; (13) Switch 2PS opens, energizing solenoid G to advance stripper 75 to push the released ground workpiece off chuck 24 back into the turret notch from which it was previously removed; when the turret is next indexed, the ground workpiece enters the discharge shoot; (14) When the stripper is fully advanced, switch 1LSA closes and switch 1LSB opens, preparing the machine for a further cycle of operation upon closing index switch 104. The machine may be arranged to function automatically so long as there is a workpiece in the uppermost turret notch.