Patent GB-803416-A (GB)
Title: Improvements relating to mechanisms for mounting work on machine tools having rotarywork spindles
IPC: B23B31/40
Filed: 1956-12-28
Abstract: 803,416. Chucks; gear-cutting. GLEASON WORKS. Dec. 28, 1956 [Dec. 30, 1955], No. 39549/56. Class 83 (3). A collet and end-clamping chuck, particularly for securing gear-blanks G to the indexible spindle 10 of a gear-cutting machine, comprises a chuck-body 15 connected to the spindle and providing a seating 27 for the rear-face of the work, a collet 28 secured to the body 15 and expanded against the bore of the work by the rearward movement, effected by a spring 16, of a member 31, a clamp 36 supporting a number of fingers 41 brought into engagement with the front face of the work by rearward movement of a draw-rod 18, and an abutment 54, on the rod 18, to move the expander 31 forwardly and allow contraction of the collet upon forward movement of the rod. The chuck, located in the spindle by its tapered-shank 22 and a key 26, is fixed by bolts 23 to a mounting-ring 24 bolted to the spindle. Screws 29 secure the collet to the shank 22, in which the expander 31 slides and is guided by lugs 34 on the chuck-body 15 and projecting between the split portions of the collet through openings in the resilient-material (102, Fig. 3, not shown), in the splits. The chuck is operated hydraulically by a cylinder 19 bolted to the spindle 10, and by a piston 17 secured to the draw-rod by nuts 56- 58 and having a sleeve-extension 54 providing the abutment engageable with a sleeve-extension 32 of the expander 31 for releasing the collet. A distributer 66 on the cylinder-head controls the hydraulic supply to the cylinder and has a passage 77 to discharge hydraulic leakage collected in grooves 61, 65 in the cylinder. An index-mechanism, with a plate 21 on the spindle and having peripheral index-notches (not shown), engaged by a pawl, is associated with a control-valve supplying hydraulic fluid to the space between flexible members 87, 88 on the spindle-housing 11 to deflect the member into binding engagement with the walls 85, 86 of an annular recess in the spindle when the indexing- mechanism is inoperative, as described in Specification 803,417. A switch 79 on the distributer co-operates with the nut 56 on the drawrod to determine the position of the rod. The fingers 41, in radial slots in the clamping-plate 36 and in a ring 39 secured to the plate, have openings 43 to receive the ends of levers pivoted in a carrier 45 bolted to the expander 31. Co-operating cam-surfaces 47-49, 51 on the draw-rod 18 and levers operate the latter on movement of the draw-rod. Springs 39, acting between the clamping-plate 36 and expander 31, are mounted on bolts 38 permitting the plate 36 a limited axial movement. Operation. To release the work, hydraulicfluid is admitted to the cylinder-space 73 to advance the draw-rod, and release the pressure applied on the fingers by a nut 35 on the drawrod and acting through the clamping-plate 36. The piston-sleeve 54 then contacts the expandersleeve 32 and displaces the expander against the force of the closing-spring 16, allowing the collet to contract and release the work, which may be removed when the fingers 41 have been retracted by engagement between the camsurfaces 47, 48.