1345875 Honing DELAPENA HONING EQUIPMENT Ltd 16 Sept 1971 [19 Sept 1970] 44732/70 Heading B3D A honing machine comprises stone pressure control means consisting of a lever 57 having a fixed fulcrum 59, a connection at a fixed distance from the fulcrum between the lever and a mechanism, having a part 55, for expanding a honing tool 16, and a member 60 contacting the lever, urged by resilient means 62 in a direction to expand the tool, and adjustable towards and away from the fulcrum. The tool 16 is mounted in an adjustable chuck 15 on a spindle 11 rotatable in bearings 12, 13 in a casing 10 by a belt-drive 17 and consists of an abrasive element 18 which is radially adjustable by an axially movable wedge 22 and is diametrically opposite a wear element 21; the chuck is radially adjustable to compensate for wear of the element. The wedge 22 is connected by a hooked portion 23 to a slot 41 in a feed rod 40, the end of which has a collar 39 radially adjustable but axially fixed to a sleeve 34 rotatable with the spindle 11. The sleeve is rotatably connected by a bearing 31 to a further feed rod 29 which is guided for axial movement in a bearing 30 in the casing 10 and has a pin- and-slot connection 27, 28 with one end of a beam 24. An intermediate part of the beam is mounted by a pivot 42 on a sleeve 43 screwthreaded on a feed spindle 45 at one end guided for axial movement in a bearing 46 in the casing 10 and, at the other end, connected by a collar 49 to a sleeve 51 axially movable by movement of a lever 53 which is operable by a foot pedal that also controls a clutch for engaging the belt-drive 17 to the spindle 11. The feed spindle is rotatable by a calibrated hand wheel 48. The other end of the beam is movable between stops 56 and connected by a pin 54 to a rod 55 connected to the lever 57 at the fixed distance from the fulcrum 59 of the lever consisting of a pin held in lugs 58 on the casing. A member 60 has a knife edge engagement 63 with the lever 57, the knife edge being between a pair of arms 61 each connected to a spring 62, the other ends of the springs being attached to a lever 64 movable into one or other of two positions by an overcentre cam 65 and hand lever 66 to vary the tension in the springs. The other end of member 60 has a surface 76 urged by a spring 77 into engagement with a cam surface 68 on a member secured to a spindle 72 which is rotatable by a calibrated hand wheel 71 and has a conical projection 73 engaging a conical recess 74 for releasably locking the spindle in position. In operation, depression of the foot pedal engages the clutch for the belt-drive 17 and further depression causes lever 53 to axially displace sleeve 51 and spindle 45 and the beam 24 to pivot about pin 54 so that the feed rods 29, 40 act to cause wedge 22 to expand the tool 16 until it engages the surface of the bore to be honed, whereupon the beam pivots about the pin 27 and transmits movement to the rod 55 and lever 57 against the action of the springs 62. Rotation of the hand wheel 71, with the conical surfaces disengaged, rotates the cam 68 to vary the point of engagement of the knife edge of member 60 with lever 57 to adjust the pressure of the honing stone against the bore of the workpiece. The variation is effected over a range determined by one rotation of the hand wheel 71, and the range is altered by operation of the lever 66. The movement of the lever 57 is proportional to the increase in diameter of the bore and the wear on the stone 18 and is shown on a dial indicator 80 connected to rod 55. The extent of radial movement on the stone 18 is adjusted by rotation of hand wheel 48 causing the sleeve 43 to move the pivot 42 of the beam. When wear of the element 21 occurs, the chuck can be adjusted so that the honing tool is central, the collar 39 being radially movable in the sleeve to permit such adjustment.