Patent GB-1255746-A (GB)
Title: A machine tool for grinding pins of a crank shaft
IPC: B24B5/42
Filed: 1969-04-18
Abstract: 1,255,746. Grinding crank-shafts. TOYODA KOKI K.K., [trading as TOYODA MACHINE WORKS Ltd.]. 18 April, 1969 [30 April, 1968], No. 20064/69. Heading B3D. A machine tool for grinding the pins 104a, 104b, 104c, 104d of a crankshaft 103, Fig. 1, comprises bearing faces 20, 90 against which journals 156, 160 of the crankshaft are clamped whilst the crankshaft is rotated for grinding a pin, and work centres 24, 91 which raise the journals 156, 160 from the bearing faces 20, 90 while the crankshaft is indexed between grinding operations. The machine also comprises a headstock 1 and footstock 11 with aligned rotatable spindles 2, 12, respectively, clamping fixtures 19, 89 mounted respectively on the spindles 2, 12 and provided with the bearing faces 20, 90 to support the crank-shaft thereon with the axis of a pin of the crankshaft in alignment with the common axis of the spindles, means for clamping the crank-shaft 103 on the bearing faces 20, 90, and indexing mechanism in the head-stock operable to turn the crankshaft relative to the fixtures 19, 89 for indexing and thereby positioning the axis of a pin or pins of the crank-shaft in alignment with the common axis of the spindles 2, 12. The work centres 24, 91 are slidably mounted in the fixtures 19, 89 and lift the crank-shaft a predetermined distance up from the bearing faces when they are advanced so that the crank-shaft can be indexed without any contact between the crank-shaft and the bearing faces. In operation of the machine, a crank-shaft 103 is placed on the clamping fixtures 19, 89 with the pins 104a and 104d lowermost. A spring-urged pin on the fixture 19 engages in a recess in the crank-shaft to position it. A magnetic clutch 17, Fig. 2, is then energized so that the drive from a rotary hydraulic motor 18 is connected via a shaft 14 to an indexing plate 21, Fig. 1, mounted on the cylinder of an hydraulic motor 22 of which the piston 23 carries the work centre 24. A recess in the plate 21 is thus urged against a spring-loaded stop 29 to accurately locate the plate so that the axis of pins 104a, 104d is aligned with that of spindles 2, 12. An aligning device is then operated to move the crank-shaft axially so that the pin 104d is located adjacent a grinding-wheel 106. Fluid under pressure is then admitted to a pair of hydraulic motors 53, 94, which causes clamping arms 57, 93 to be moved to clamp the journals 156, 160 against the bearing faces 20, 90. The clutch 17 is then de-energized and the aligning device withdrawn. The spindles 2, 12 are then rotated by a shaft 6 and the grinding-wheel 106 fed in on a slide to effect grinding of the pin 104d. When the pin is of the desired size, a signal is generated to retract the wheel 106. The pin 104a is then aligned with the wheel 106 as described for the pin 104d and ground to size. The pin 104c is then positioned opposite the wheel 106 while the spindles 2, 12 are stationary, and the clamping arms 57, 93 are released. The work centres 24, 91 are then advanced by their hydraulic motors to raise the crankshaft from the bearing faces 156, 160, and these are then cleaned by air jets applied through nozzles 67, 68, 98, and 99. The clutch 17 is then reenergized so that shaft 14 and hence indexing plate 21 and the crank-shaft 103 are rotated. After 180 degrees rotation, an arm 74 on the shaft 14 actuates a switch 73, Fig. 2, which reverses the motor 18 and rotation is reversed until the stop 29 engages in a second recess in the plate 21. The centres 24, 91 are then retracted, the pin 104c aligned with the wheel 106 and the clamping arms 57, 93 actuated so that the crank-shaft is held with the pins 104c, 104b coaxial with the spindles 2, 12. The pins 104c, 104b are then ground in the same manner as pins 104d, 104a before the crank-shaft is indexed to its original position, in a manner similar to the first indexing, and is then removed.