Patent GB-1031933-A (GB)
Title: Grinding machine
IPC: B24B47/06
Filed: 1963-04-11
Abstract: 1,031,933. Grinding. HEALD MACHINE CO. April 11, 1963 [Aug. 17, 1962], No. 14562/63. Heading B3D. A grinding machine for the internal grinding of a rotating workpieee has a base, a workhead table mounted on the base, the workhead table including a lower member and an upper member slidable relative thereto along an imaginary line, and a wheelhead table also mounted on the base, the wheelhead table including a lower member and an upper member slidable relative thereto in a direction extending transversely of the said line, a first swivel member being mounted on the upper member of the workhead table and being adapted to carry a workhead with a workpiece, a second swivel member being mounted on the upper member of the wheelhead table and being adapted to carry a wheelhead with an abrasive wheel, and means being provided for bringing about sliding movement of the upper members of the workhead and wheelhead tables to bring about engagement of the wheel and workpiece for a grinding operation. During "rough grind " with high grinding pressure the workpieee 31, Fig. 33, is inclined at an angle B to line XX and the wheelhead 13 at an angle C. During " finish grind " with low grinding pressure, Fig. 31, the workpiece remains at the angle B but the wheelhead angle C is reduced to zero. By thus compensating for the deflection of the grinding-wheel spindle a cylindrical bore or one having a desired taper is produced. General.-A grinding machine has a workhead 12 and a wheelhead 13 mounted on a base 11. Around the front of the base is a removable splash guard 14. Transverse shoots 34 in the base 11 terminate in a longitudinal trough 35 leading to a pipe 21 returning coolant to a tank 19. A control cabinet 18 has wheels running on rails carried by arms 16, 17 projecting forwardly from a superstructure 15 extending upwardly from the rear of the base; the cabinet is connected to the rest of the machine by flexible cables 62 and can be moved from a forward position, in which it is accessible but overlies the working elements, to a rearward position in which it is out of the way. Workhead.-The workhead 12 is of the type carrying a set of shoes on which an annular workpiece 31, e.g. the oute race of a roller bearing, is mounted for rotation about its axis while its bore is ground. The workhead 12 is bolted on a swivel member 25 mounted on a slide 24 movable, in the general direction of the workpiece axis, i.e. longitudinally of the machine, on a member 23 bolted to the base 11. The longitudinal movement of the slide 24 effects advance of the workpiece toward the grinding-wheel and reciprocation of the workpiece during grinding. The member 23 has a flat way 38 and a V-way 42 on which the slide 24 moves. The line of action of the workpiece and winding-wheel is located substantially above the way 38. The slide bearing surface 41 co-operating with the flat way 38 has a circular hydrostatic pocket 87 surrounded by a relief groove 119 having a radial groove 121; the way 38 is flanked by drain ways 122 123. Oil is supplied to the pocket 87 from a manifold 127 through a thin coil 125 of plastic tube, steel tube 124 and passage 88 in the slide 24. The surface 41 has a second pocket 117 supplied through a passage 118. The slide bearing surfaces co-operating with the V-way 42 have pockets 89, 91, 115, 116 supplied through passages. The passages supplying the above-mentioned pockets lead back to an oil box 94 mounted at the rear of the slide 24 and containing the manifold 127 and the restriction coils such as 125. A fan 45 located at the rear of the base 11 supplies air through a conduit 44 to the spaces between the slide 24 and the member 23; the outward flow of air prevents the access of abrasive swarf and moisture to the sliding parts. The slide 24 has side apron portions 46, 47. The left-hand end of the slide 24 has an apron portion 95 in which are formed doorways 96, 97 corresponding to the flat way 38 and V-way 42, flexible webs being mounted in the doorways to restrict the flow of air therethrough ; a similar arrangement is provided at the right-hand end of the slide 24. Movement of the slide 24 to the left is limited by a shock-absorber 71 mounted on the member 23. A piston 74 secured to the member 23 is located in a cylinder 75 secured to the slide 24. A vertical shaft 81 mounted in the member 23 has at its lower end a pulley 82 driven by a motor 66 and at its upper end an inner cam portion 84 on which is rotatably adjustable an outer cam portion 85 co-operating with a roller follower 86. The follower 86 is mounted on one end of a crank arm 98 pivoted on an extension of the slide 24. The other end of the crank arm is engaged by the rod of a piston 110 located in a cylinder bore in the slide 24. Pressure oil conduits lead to opposite sides of the pistons which thus acts as a shock absorber and maintains the crank arm in a normal position of clockwise rotation about its pivot. Dogs 61 on the slide 24 no-operate with switches carried by a switch box 59 on the member 23. The top surface of the slide 24 has a diagonal T-slot 104 in which a slide 105 is adjustable by a screw 112. The slide 105 carries a bolt 109 which extends through a closely fitting bore in the swivel member 25. Bolts mounted in a threaded aperture 106 in the slide 105 and in a threaded aperture 108 in a second slide 107 project through arcuate slots in the swivel member 25, these slots being concentric with the first bolt 109. The slide 105 carries a pinion gear 114 engaging an arcuate rack on the swivel member 25, the rack being concentric with the pivot bolt. Wheelhead.-The wheelhead 13 comprises a spindle 32 carrying a grinding-wheel 33. The wheelhead and its drive motor 29 are bolted on a swivel member 36 mounted on a slide 28 movable, transversely of the machine, on a member 27 bolted to the base 11. The transverse movement of the slide 28 feeds the grinding-wheel towards the workpieee. The member 27 has a flat way 48 and a guide bar 53 on which the slide 28 moves. The guide bar 53 is secured to parts 194, 195, 196 of the member 27 and extends through bores in parts 199, 201 of the slide 28. Each bore has hydrostatic pockets 203 arranged in groups of three around the bar and supplied through restriction coils 205 from a manifold 206. The flat way 48 has hydrostatic pockets similar to those already described in connection with the flat way 38 for the workhead slide 24. An oil box is provided. The slide 28 has side aprons 55, 56 and end aprons 197, 198. At its left-hand end the bar 53 has a reduced portion 207 extending through a cylinder head 208 secured to the part 199 to form a cylinder to which pressure oil can be admitted through a passage 209 to move the slide 28 forwardly of the machine and so move the grinding-wheel out of contact with the workpiece. At the other end the bar 53 has a reduced portion extending through a cylinder head 212 secured to the part 201 to form a cylinder to which pressure oil can be admitted through a passage 213 to move the slide 28 rearwardly of the machine and so feed the grinding-wheel to the workpiece. Dogs 58 on the slide 28 co-operate with switches carried by a switch box 57 on the member 27. Forward movement of the slide 28 is regulated by the engagement of a stop 131 thereon with a compensating slide 132 carried in a horizontal guideway 139 on the member 27. A spring-loaded pin 163 mounted in the guideway 139 presses against a portion 160 of the slide 132 to urge it forwardly. The slide 132 is also controlled by a compensating screw 133. Mounted at the front of the slide 132 are a switch 164 for terminating the " rough grind " portion of the cycle and setting up the " finish grind " portion of the cycle, and a switch 134 for terminating the grinding cycle; the switches are actuated respectively by pins 228, 165 adjustable on the apron 197 of the slide 28. The compensating screw 133 can be rotated by a handwheel 147, through a chain drive 149, or automatically. A reset motor 136, for moving the slide 132 back when a worn grinding-wheel is replaced by a new wheel, is connected to the screw 133 through a gear reduction unit 137, a chain drive 138, an electric clutch 141 and a clutch 142. The outer shell of the clutch 142 is connected by a metal band 143 to one end of the piston rod 144 of a compensating cylinder 145, the other end of the piston rod co-operating with a cone 146, the setting of which determines the stroke of the piston rod. The cone 146 is mounted on a shaft 151 having a piston 152, located in a cylinder 153, and a flange 154 engageable alternatively with flanges 155, 159 on shafts threaded into a block 157 and rotatable by knobs 158, 162 respectively. Although the apparatus would normally use the controlled-force feed method provision is made for using the controlled-rate feed method. A pin 216 located on the apron 197 of the slide 28 is associated through screw means with a shaft 215 having a gear 214 engaging a rack 217 on the rod of a piston 218 in a cylinder 219. Pressure oil is supplied to the cylinder either through a valve 222 adjustable by a knob 225 to control the feed during " rough grind " or through another valve adjustable by a knob 226 to control the feed during " finish grind." A dial indicator 223 has an actuating rod extending through the apron 197 into contact with an extension of the compensating slide 132 so as to show the position of the slide 28. The swivel member 36 has undercut recesses 166, 167. Reeds 168, 171 are fastened to vertical surfaces of the recesses and by plates 169, 172 to the upper surface of the slide 28. The lefthand end of the swivel member has a notch 173, over which the wheelhead 13 is mounted, flanked by undercut recesses 174, 175. A member mounted on the surface of the slide underlying the notch 173 has reeds 177, extending upwardly and attached to vertical surfaces of the recesses 174, 175. The swivel member thus moves as though it were