Patent GB-963864-A (GB)
Title: Dynamically actuated balancing means
IPC: B24B41/04
Filed: 1962-08-10
Abstract: 963,864. Correcting rotary unbalance. NORTON CO. Aug. 10, 1962 [Dec. 13, 1961], No. 30723/62 Heading G1X. [Also in Division B3] A grinding wheel spindle assembly having means for adjusting the balance of the grinding wheel without having to stop the machine comprises a shaft 38, a shaft 40 which carries the grinding wheel 70 at one end and is mounted for axial movement within, and rotation with, the shaft 38, balancing means 80 carried by the shaft 40 and arranged to be locked for rotation with the spindle assembly when the two shafts are in a first relative axial position (i.e. that shown) in which respective bearing portions 42, 62, 46 and 44, 64, 48 on the two shafts coact to maintain them in correct concentric relation, and actuating means 116 for the balancing means disposed in an axial passage 118 in the shaft 40 and arranged to move axially with the latter shaft until the bearing portions are disengaged to free the shaft for flexing relative to the shaft 38 and thereafter to be stopped while the shaft 40 continues to move to an extent sufficient to unlock the balancing means 80 and permit them to rotate relative to the shaft 40. The shaft 38 is mounted in bearings 39 on a slide 10 for drive by a pulley 121, and the left-hand end of the shaft 40 carries a conical support 54 for a hub 56 on which the grinding wheel 70 is mounted. The end portion 78 of the shaft 40 projects through the hub into a chamber 72 on the latter and carries a lock nut 90 for the hub, balancing means 80 in the form of three weights 84 rotatably mounted on the portion 78 for axial movement with the shaft, and a locking ring 82 held by the nut 90 against springs 98 housed in recesses 100 in the hub. In the position shown, the shaft 40 is maintained in coaxial relationship with the shaft 38 by the coacting bearing surfaces 42, 44 and 46, 48 on the two shafts and similar surfaces 62, 64 on the hub 56 and shaft 38; also in this position, the conical tips of screws 108 threaded through the weights 84 engage in radial grooves 104 in the locking ring 82 and so hold the weights against rotation relative to the shaft 40. Mounted at the right-hand end of the assembly is a piston 142 operable in a fluid pressure cylinder 144 to control the axial movement of the shaft 40; also movable with the shaft 40 at this end is a sleeve 150 and hollow shaft 156 within which is a spring 158 bearing between the inner end of the hollow shaft and a collar 160 on the end of a rod 116 which extends axially through the shaft 40 and at the left-hand end carries a disc 114 mounting a sleeve 112 serving to limit the leftward movement of the locking ring 82. To effect balancing, the shaft 40 is moved to the left by admitting fluid pressure to the cylinder 144, thus disengaging the bearing surfaces referred to and freeing the shaft 40 for flexing movement about the axis of the shaft 38. During the initial movement of the shaft 40, the rod 116 moves with the shaft and therefore the locking ring 82 remains engaged with the screws 108 to hold the weights 84 in locked condition. Where, however, the movement of the sleeve 150 is sufficient to cause a screw 172 to engage the end of the cylinder 144 the rod 116 is stopped and since the locking ring 82 is then prevented from leftward movement, the continued movement of the shaft 40 results in the screws 108 being disengaged from the locking ring and so releasing the weights 84 for their balancing operation. Upon reverse operation of the piston 142, the weights 84 are locked by the screws 108 before the shaft 40 becomes properly located by the bearing portions in the shaft 38. The screw 172 can be adjusted to vary the point at which the rod 116 and shaft 40 move together axially in the leftward direction. The spindle assembly is reciprocable in its bearings 39 by means of a forked lever 36 acted upon by a cam driven through worm gearing 32 from the shaft 38. U.S.A. Specification 3,107,550 is referred to.