Patent GB-1429018-A (GB)
Title: Internal grinding machines
IPC: B24B55/00
Filed: 1973-09-11
Abstract: 1429018 Grinding TOYODA-KOKI KK 11 Sept 1973 [19 Oct 1972] 42587/73 Heading B3D  A machine for internally grinding a workpiece W comprises a grinding wheel 19 carried by a wheelhead 50 on a table 37 movable towards and away from a spindle head 2 slidably mounted on a bed 1, a spindle 7 rotatably mounted in the head and having a chuck housing 11 fixed at one end and providing a reference face 12, and clamping means 16 axially slidable relative to the spindle to clamp the workpiece to the reference face. Aligning means 24 are disposed within the spindle to establish alignment between the axes of the spindle and workpiece by engagement with the cylindrical bore of the workpiece, and positioning means 20, 21 are operatively connected to the aligning means to project the same from the chuck housing so that the workpiece may be received on the aligning means. The spindle head 2 has a main body 5 adjustable angularly about a pivot 6 on a base 3 slidable on a guideway 4 of the carriage 2a on the bed 1. The spindle 7 is rotatable in the head and at one end has a face plate 10 carrying the chuck 11 to which is attached the reference face 12. An operating member 13 is axially slidable in the spindle and has a pivot 15a for a supporting disc 15 having pivots 17 for jaws 16, movement of the operating member to the left causing cam surfaces 16a to co-operate with holes 12a in the face 12 to pivot the jaws against springs 18 and clamp the workpiece to the reference surface. The operating member is connected to a piston 21 slidable in a cylinder 20 secured to the main body 2 and fluid is supplied to the ends of the cylinder through a rotatable distributor 22. A plate 39 is secured to the operating member and obstructs an air nozzle 40 of a detector 44 when the member is in the position in which the jaws effect clamping of the workpiece. A rod 23 is disposed within the operating member 13 and at one end has a measuring gauge 24 having a tapered portion 24a and a cylindrical portion 24b. The other end of the rod has a rotatable member 25 connected by a ball 28 to a first swing arm 27 carried by a shaft 30 connected by a coupling 31 to a second shaft 32 rotatable in a bracket 29 on the main body 2. An arm 35 is secured to the coupling 31 and a second swing arm 33 is secured to the lower end of the shaft 32. A cylinder 36 having a pair of pistons 46, 47 is secured to the body 2, the piston 47 having an abutment 48 for engagement with the arm 35 of the coupling which is engaged with a limit switch 45 during retraction of the rod 23, the pistons being operable to position the rod 23 and house the gauge 24 in any one of three positions, a retracted position, an intermediate position, in which the tapered portion 24a extends from the face 12 for alignment of the workpiece, and an extended position in which the cylindrical portion 24b is projected from the face to measure the workpiece. The second swing arm 33 is movable against a spring 34 by an abutment 38 on the table 37 carrying the grinding wheel when the wheel is advanced into the workpiece to retract the alignment and measuring gauge 24 from the workpiece. In operation, when a workpiece is fed to the chuck, the pistons 46, 47 are positioned to act on the arm 35 and hence the member 23 to position the gauge 24 so that its tapered portion 24a extends from the reference face 12 and receives the workpiece W which is thereby aligned while the piston 21 is moved to cause the operating member to move the jaws 16 to clamp the workpiece on the face. When clamped, the plate 39 obstructs the nozzle 40 and valve 44 is actuated to cause the pistons 46, 47 to move the gauge to its retracted position so that the grinding wheel can be advanced for rough grinding. After rough grinding, the wheel is dressed and the workpiece finely ground. The pistons 46, 47 are actuated to cause the rod 23 to advance the gauge 24 until its cylindrical portion 24b is extended from the reference face. If the bore of the workpiece has not been sufficiently ground, the portion 24b cannot enter the bore and the grinding wheel is again advanced to effect further grinding, the abutment 38 engaging the second swing arm 33 to cause retraction of the gauge as the wheel is advanced. When the bore is to size, the gauge enters the bore and a limit switch 42 is actuated by a bolt 43 on the arm 27 to retract the grinding wheel and unclamp the workpiece.