GB957577A - Automatic balancing means - Google Patents

Abstract

957,577. Grinding. NORTON CO. April 11, 1962, No. 13946/62. Heading B3D. Apparatus for balancing a rotatable element, such as a grinding wheel 36, comprises balancing means 175 periodically operable automatically to complete a balancing operation in response to a given signal impulse to balance the rotatable element, sensing means automatically operable in response to a predetermined stimulus to generate a given impulse, and means operatively interconnecting the sensing means and the balancing means to transmit the given impulse from the sensing means to the balancing means. The balancing means consists of weights 175 freely rotatably carried on the end of a rod 101 having a tapered portion 156 to which is secured a portion 25 of a spindle 23, the grinding wheel 36 being secured by a nut 75 to the portion 25. The tapered portion 156 is at the end of flexible tapered portion 142 of the rod which has a part 145 slidable in a part 24 of the spindle. The end of the rod 101 is rotatably supported by bearings 105 in a piston 102 slidable in a cylinder 111 prevented from rotating by an arm 131 engaging a fork 133. The cylinder is supported by bearings 121 in a sheave 33 which is secured by a nut 65 to the spindle part 24 and driven by belts 34 from a pulley 32 on the shaft of an electric motor 31. The portion 25 of the spindle carries a ring 181 which is normally urged by springs 182 to position wherein serrations 182 on its face are engaged by pins 176 carried by the balance weights to retain the weights in their adjusted positions. Cables 193 between the ring 181 and a flange 191 permit the ring to move only a portion of the movement of the rod 101 so that during a balancing operation, when the rod is moved to the left from the position shown, the pins are disengaged from the serrations to free the weights. In operation, the grinding which is reciprocated axially by rocking movement of a forked lever engaging a non-rotatable sleeve 42 on the spindle 23, the lever being rocked by a cam or eccentric rotated by a worm wheel driven by a worm 48 on the spindle. A sensing means, which may be responsive to a predetermined degree of vibration, the passage of time, or the completion of a number of grinding operations, operates an electro-hydraulic circuit to start a balancing operation by actuating a timer TR1, a warning light 2 and a solenoid S1 to move a valve spool 228 of a valve V1 to an alternative position to that shown in Fig. 5. Fluid pressure from a pump P then passes to a conduit 116 leading to a chamber 118 of the cylinder 111 to move the piston 102 to the left. The movement of the piston displaces rod 101 firstly to disengage a conical part 152, Fig. 2, of the rod from a seating 154 so that the part 25 of the spindle carrying the grinding wheel is now free to move radially, being supported only by the flexible tapered portion 142 of the rod 101. Further movement of the rod 101 causes the pins 176 associated with the balance weights to be disengaged from the serrations of the locking rings, the weights then automatically moving to a position to effect balancing of the wheel. After a period of time determined by the timer TR1, the solenoid S1 is de-energized to permit the spool 228 to return to its initial position and reverse the fluid pressure connections to the cylinder 111. The return movement of the rod 101 causes the pins 176 to re-engage the serrations of the locking ring 181 and then the conical part 152 of the rod to engage the seating 154 to prevent radial movement between the parts of the spindle. At the completion of the return movement, a solenoid S2 of a valve V2 is energized to direct fluid pressure to the cylinder of a truing diamond. At the end of the stroke of the diamond across the wheel, a limit switch LS1 is operated to deenergize the solenoid S2 to move the valve to its initial position and return the diamond to its initial position. Push buttons permit a balancing and/or truing operation to be initiated independently of the automatic means. When the sensing means are of the type responsive to vibrations, a timer PR3 is provided which is operative during starting of the grinding wheel from rest so that it is only the vibrations produced when the wheel is running at its operative speed which actuate the automatic balancing means. U.S.A. Specifications 1,584,717, 1,808,401 and 1,967,163 are referred to.