Patent GB-1218841-A (GB)
Title: Honing, grinding and finishing machines
Inventor: SUNNEN JOSEPH
IPC: B24B33/06
Filed: 1968-02-05
Abstract: 1,218,841. Honing, grinding and finishing machines. J. SUNNEN and A. SUNNEN Jnr. 5 Feb., 1968, No. 5761/68. Heading B3D. A machine of the type operating on cylindrical surfaces by rotating a tool relative to the surface and reciprocating it parallel to the surface axis, includes means sensitive to the instantaneous torque necessary to rotate the tool which controls the speed of the tool. The speed varied may be that of reciprocation, permitting dwell to remove " high spots" or alternatively the speed of rotation may be altered. A honing tool 36 is connected by a universal joint 34 to a drive tube 30 connected by a universal joint 32 to a spindle assembly 28 rotated (through belts 26, 22, 18 and clutch 14) by a motor 10. The motor 10 is mounted on an arm 38 pivotally supported by a shaft 40 on the machine base. The motor 10 drives (through the clutch 14, the belt 18 and a belt 44) a coupling device 50 which drives (through a belt 56 and a gear reducer 62) a crank 66. To the crank 66 is pivotally connected one end of a rod 68 the other end of which is pivotally connected by a member 69 to a rocker 70. The rocker 70 is pivoted on a shaft 72 mounted on a plate 74 fixed to the arm 38. The rocker 70 includes a rod 76 on which a slide 78 is adjustably secured; for accurate adjustment a pointer 90 on the slide 78 registers with a scale 88 positioned adjacent the rod 76. The slide 78 is pivotally connected to a rod 80 secured, by a releasable coupling 86, in a tube 82 pivoted at 84 to the machine base. Rotation of the crank 66 thus effects reciprocation of the tool 36, the ampli. tude of the stroke being determined by adjusting the slide 78. On releasing the coupling 86, the arm 38 can be raised by a handle 92 to lift the tool 36 above the workpiece W. The coupling device 50 in the drive to the crank 66 is preferably electromagnetic, e.g. an eddy current device. The amount of slip in the coupling device 50 is determined by a winding 110 receiving a signal corresponding to the input current required to drive the motor 10, which is sensed by a transformer winding 100 coupled to an input lead 98. When the torque on the tool 36 increases the speed of the crank 66 is substantially simultaneously reduced. The electric circuit, Fig. 5, includes a nulling potentiometer 115 whereby only currents greater than no-load are available at the control circuit input. The grid circuit of a thyratron 116 includes a control potentiomoter 118 one side of which, marked " slow " is supplied with halfwave rectified negative voltage and the other side of which, marked " fast," is supplied with half-wave rectified positive voltage. Under normal operating conditions potentiometer 118 is adjusted to produce a positive potential on the grid somewhat greater than the minimum necessary for conductivity of the thyratron. When a load increase is detected by transformer 100 an increasing negative potential is produced by the sensor circuit. The magnitude of the current surge produced and the setting of potentiometer 118 establishes the degree of conductivity or non-conductivity and hence the power delivered to the clutch winding 110 of the eddy current device 50. The output of the coupling can be varied from a normal preestablished stroking rate to a condition wherein the stroke rate is very slow. Factors which affect the torque include bore diameter variations, condition of the stores, material and construction of the work, finish of work surface, portions of work having different hardness, type of lubricant and type of feed-up mechanism. Mechanical load sensing devices may be used instead of electrical means; these can include mechanical or electrical transducers or strain detectors. Means sensing the tension in one or more of the drive belts may be used. The coupling device may alternatively be a magnetic particle type clutch, an hydraulic coupling device or any other variable slip electrical or mechanical device. The control means may be caused to increase the speed of rotation of the head 36 as increase of torque is sensed and vice versa.