Patent GB-397718-A (GB)
Title: Improvements in or relating to apparatus for truing the grinding discs of grinding machines
IPC: B24B53/08
Filed: 1932-11-15
Abstract: 397,718. Trueing rotating tools. WERNER AKT.-GES., F., Marienfelde, and JUNGE, C., 20, Kaiserallee, Marienfelde, Berlin. Nov. 15, 1932, No. 32290. [Class 60.] Diamonds 2, 3, 4, Fig. 1, are moved to and fro against a disc 1 of a grinding machine by a plurality of hydraulic pistons 13, 14, 7, Fig. 3, the movements of which are automatically started and finished. One of the pistons 7 is connected with a main control valve 23 controlling the movements of the other pistons, so that mutual adjustment of the piston strokes is obtained. Counting mechanism 27 &c. is used to bring the apparatus to a stop after a predetermined number of strokes. A carrier 5 of the diamond 2 can rotate about an axis 6 and is firmly attached to the hydraulic wing piston 7. All the diamonds have micrometer adjustment and those marked 3, 4 can be moved parallel to the sloping edges of the disc 1 by the pistons 13, 14. Cylinders 15, 16 with the casing carrying the rotary piston 7 are firmly connected together on a carriage 18 which can be adjusted along another carriage 21, Fig. 11, by a screw spindle 20. In Fig. 3 the sections of the three cylinders are shown as lying in the plane of the drawing. A casing 22 of the control valve 23 is joined to the cylinder 17 of the rotary piston 7 and on the same axis. The spindle 6 on the rotary piston 7 is continued into the casing 22 to form a slotted rotating body 24. A sliding piece 26 fits a slot 25 in the body 24 and is firmly fixed to the control valve 23 so that this valve rotates with the piston 7. The control valve can however move axially relatively to the piston. A member 23<1> of the valve 23 has channels 49, 50 which communicate alternately with inlet channel 51 and outlet 52 and cause axial movement of the valve 23. The wing piston 7 can rotate between stops 57, 58, Fig. 8, through 90‹. One end of the casing is connected through channel 59 with the pressure conduit and the other alternately to the pressure conduit or the return through channel 60. The effective surfaces of the piston 7 are unequal, pressure by the channel 59 acting upon the smaller one. Pressure from channel 60 would rotate the piston against constant pressure from 59. The hydraulic counting-mechanism, Fig. 3, consists of a piston 47 in a cylinder connected to two opposed racks 27, 28 the teeth of which are alternately held by catch teeth attached to pistons 29, 30 in a cylinder 31. Pressure fluid enters at 32 to act permanently on the upper free surfaces and at 33 from time to time against the lower surfaces. In each piston the effective underside is the greater. Also the lower side of 29 is greater than that of 30. Pressure from above actuates piston 30 first and similarly 29 from below. Piston 47 is limited in movement by adjusting screw 34. If flow through 35 is interrupted spring 36 acts and presses piston to right and the teeth of the racks against catch teeth of pistons 29, 30. For commencing the movements the valve 37 guided in cylinder 65 is used, a rod 38 resting against a controlling rotating cam disc 41. Channels 42 are provided in a part 37<1> of the valve to lead pressure oil entering at 43 continuously to left face of valve to press roller 39 against cam 40. The valve 37 is connected to a double-armed lever 45 carrying a pawl 66 engaging ratchet wheel 46. The ratchet is firmly attached to the shaft 20. When the valve moves left the carriage 18 is driven towards the grinding disc. Operation is as follows. The valve 37, Fig. 3, is forced right by driving medium from channel 43 through channel 42 to its left face with roller 39 against shallow part of cam disc 41. The driving medium passes from 43 through cylinder 65 and channel 35 to right side of piston 47 pressing it left against the spring 36 to screw 24. Supply channels 53, 51 are shut off by valve 371. The driving means however flows constantly from the pump through the channel 61 to the right face of control valve 23 and holds it fixed in the left-hand end position. It also flows through 54, 55 to upper side of piston 14 and holds it fixed against constant pressure from 56. Finally pressure flows from 55 through 33 against lower surfaces of pistons 29, 30 and keeps them in their highest position, the catch tooth of piston 29 engaging in a tooth of rack 27. Wing piston 7 is held as in Fig. 5, and 13 as in Fig. 3, as conduits 60, 62 are connected through control valve 23 with return 63 while pistons receive pressure through conduits 59, 64. By rotating shaft 40 the valve 37 can be brought to position, Fig. 6. Carriage 18 is thereby moved an amount corresponding to the layer to be removed from the disc by the diamonds. The channel 35 is closed and piston 47 is pressed by spring 36 and flow is released from 43 through 65, 53 and channel 48 to 51. The pressure medium passes from channel 51 to 49 to left side of piston 23 and drives it right, the sliding piece 26 moving in the slot 25. In this way supply 54 connects with 60, 62 and channel 55 to waste 63. Pressure reaches larger surface of wing piston 7 and rotates it counterclockwise whereby diamond 2 makes operating stroke. Piston 13 is forced down and piston 14 upwards thereby executing their movements with diamonds 4, 3. By rotation piston 7 has brought sliding piece 26 into position, Fig. 6. Channel 50 is connected to discharge and connection of 57 with 49 is interrupted. Valve 23 returns to position, Fig. 3, and the diamonds to the position, Fig. 1. With return rotation of piston 7 valve 23 is returned to position, Fig. 3, and action would commence anew if strokes were not limited by the counting mechanism 27, 28, &c. At the first axial movement of the valve 23 to the right, the lower side of pistons 29, 30 are connected through channels 33, 55 with the waste. Pressure by channel 32 reaches upper sides of pistons and gives them a downward movement, and piston 30 moves first and places itself in front of the next tooth of rack 28. When piston'29 releases a tooth, the rack 29 is forced right by the spring 36. When the valve 23 is displaced left piston 29 moves upwards to catch by means of rack 27 the piston 47 released by upward movement of piston 30. After a predetermined number of displacements piston 47 shuts off conduits 53, 51 preventing further strokes. The starting position of the piston 47 is determined by adjusting the screw 34 thus fixing the number of strokes. Instead of a hydraulic counting mechanism a mechanical one, Fig. 9, can be used. A rod 100 is connected with the valve 23 and shares in the axial but not in the turning movements of the valve. A pawl 101 rotates in a cavity of the rod with one end in connection with a fixed stop 103 and the other partly in a rack 104 and partly over a slide behind it. A block 106 carrying the rack 104 has a slanting guide groove 107 in which is guided the slide 105 with a corresponding rib. The slide is supported against the block by a spring 110. A rod 111 attached to the slide can move in the guiding piece 112. The guide 112 is attached to the rod of the hydraulic piston 113, the cylinder 109 of which is in connection on the one side through the conduit 35 with the cylinder 65 and on the other through conduit 114 with the discharge. In the position shown, the driving medium flows from 65 through 35 to the right of piston 113 and presses block 106 against the screw 115 through the slide 105 and spring 110. If the valve 37 is moved left by the cam 41 the valve 23 carries out its double strokes as before. During displacement towards the right the pawl 101 acting on the rack 104 takes the block 106, slide 105, and piston 113 with it through distance of one tooth until it is lifted out of engagement by the fixed stop 103. This is repeated until the slide 105 strikes against a fixed stop 116.