Patent GB-575361-A (GB)
Title: Improvements in or relating to work-holding devices for machine tools and the like
IPC: B23B31/12
Filed: 1944-03-13
Abstract: 575,361. Chucks. GOOD, I. E., and KEIGHLEY GRINDERS (MACHINE TOOLS), Ltd. March 13, 1944, No. 4599. [Class 83 (iii)] In a chuck operating mechanism of the kind in which the chuck may be operated whilst rotating, by endways movement of an operating member mounted coaxially with the chuck spindle and moved by the thrust exerted on a circumferential abutment on the said member by a non-rotating control means, the control means has a connection to an abutment which engages a corresponding abutment on the chuck-spindle, the said connection being such as to urge the abutments oppositely to the movement of the chuck-operating member so that the reaction of the displacing force exerted by the control means on the operating member is transmitted to the spindle and balances the force transmitted to the spindle from the operating member. The chuck comprises a back plate 16 secured to the spindle 11 by screws 17 and a main body 14 comprising a cylindrical outer wall and an internal flange 18. At three equidistant places the cylindrical wall is cut away and its outer surface machined to afford flat faces to which are screwed plates 20 which support wedges 21 on which slide the chuck jaws 22. Jaw-operating blocks 27 pivoted on pins 26 are connected to resilient tongues 28 which pass through the flange 18 and are screwed to a head 30 mounted on a shank 31 screwed into the chuck operating member 33 and secured by a locking screw 34. The member 33 passes through the spindle 11 mounted in bearings, not shown, in the headstock casting 12 and extending into a casing 40 supported from the casting 12 by a bracket 41. A slidable but non-rotatable cup member 47 within the casing 40 engages an extension or abutment 42 of the spindle through a thrust bearing 48, 49 and a similar opposed cup member 50 at the other end of the casing engages a shoulder 53 on the operating member 33 through a thrust bearing 51, 52. The ends of the cup members are internally screwthreaded with threads of opposite hand and are coupled by a screw-threaded sleeve 58 surrounded by a gear ring 59 adapted to be rotated through gearing from a hand lever 65 (not shown) outside the casing. Rotation of the hand-lever and sleeve 58 in one direction draws the cup members 47, 50 together, thus moving the operating member 33 outwardly relative to the spindle 11 thus opening the chuck jaws 22. Movement of the hand-lever in the opposite direction moves the members 47, 50 apart thus allowing the chuck to be closed through the action of two compression springs 44, 45 acting between the spindle extension 42 and a collar 46 screwed on to the operating member 33, The thrust of the springs may be adjusted by altering the position of the collar on the member 33 by inserting a tommy bar into holes 72, 80 while rotating the spindle. According to the Provisional Specification the chuck comprises a split collet movable endways within a conical bore in the chuck body. Specification 550,460 is referred to. Lubricating machines and work.-The chuck jaws are lubricated through a nipple 36 and the cup-members and sleeve 58 through cups 75 and passages 76. Lubricant is supplied to the work 24 through a passage 66 and a bore in the member 33 and locking screw 34, a thrower 70 preventing leakage into the mechanism. Lubricant thrown off by the thrower is collected by a pipe 73.