Self-centering jaw chuck

Abstract

A self-centering, radially reciprocating jaw chuck for machine tools and the like comprising a chuck body member, a plurality of master jaws secured to the body member, each of the master jaws having a pair of circumferentially spaced fixed portions rigidly secured to the body member and a radially reciprocable portion positioned circumferentially between the fixed portions. Resilient means integral with both the fixed portions and the radially reciprocable portion connect these portions, and a work gripping member is secured to each of the radially reciprocating portions. Axially reciprocable means is provided within the body member for radially reciprocating the radially reciprocable portions, and work gripping members attached thereto, whereby flexure of the resilient means provides a self-centering action of the work gripping members with respect to the longitudinal axis of the chuck and the work.

What is claimed is: 
     
       1. A radially reciprocating jaw chuck for machine tools and the like comprising: a. a chuck body member,   b. a plurality of master jaws,   c. each of said master jaws .Iadd.being symmetrical about a radial line passing through the center thereof and .Iaddend.further having a .[.pair of circumferentially spaced.]. fixed .[.portions.]. .Iadd.portion .Iaddend.rigidly secured to said body member and a radially reciprocable portion .[.positioned circumferentially between said fixed portions.].,   d. .Iadd.a pair of leaf members .Iaddend.resilient .[.means.]. integral with and connecting said fixed .[.portions.]. .Iadd.portion .Iaddend.and said radially reciprocable portion .Iadd.and chordally disposed with respect to said body member.Iaddend.,   e. work gripping members secured to each of said radially reciprocable portions,   f. cam means axially reciprocable in said body member .[.for.]. .Iadd.operable to .Iaddend.radially .[.reciprocating.]. .Iadd.reciprocate .Iaddend.said radially reciprocable portions and associated work gripping members between work gripping and release positions,   g. whereby the flexure of said resilient .[.means provides.]. .Iadd.leaf members provide .Iaddend.a self-centering action of said work gripping members with respect to the longitudinal axes of the chuck and the work. .[.   
     
     
       2.  A jaw chuck as in claim 1 and wherein: a. each of said master jaws is symmetrical about a radial line passing through the center thereof..]. .[.3. A jaw chuck as in claim 2 and wherein:   a. said integral resilient means comprises leaf means..]. .[.4. A jaw chuck as in claim 3 and wherein:   a. said leaf means comprises a pair of leaf members associated with each of   
     
     
        said master jaws..]. 5. A jaw chuck as in claim .[.4.]. .Iadd.1 .Iaddend.and wherein: a. each of said leaf members of each pair is substantially U-shaped with each leg of each leaf member of each pair being parallel to the other legs   
     
     
        of said pair. 6. A jaw chuck as in claim 5 and wherein: a. said body member is circular, and   b. each leg of each leaf member of each pair is chordally disposed with   
     
     
        respect to said body member. 7. A jaw chuck as in claim .[.2.]. .Iadd.1 .Iaddend.and wherein: a. said axially reciprocable cam means comprises a draw plug axially reciprocable in said body member,   b. a cam plate member secured to each of said master jaws on an inner surface thereof,   c. a recess in each of said master jaws adjacent said cam plate member,   d. an elongate slot in each of said cam plate members,   e. a cam head in each of said recesses between said cam plate member and said master jaw,   f. bolt means passing through said slot for securing said cam head to said draw plug,   g. whereby upon reciprocation of said draw plug, said cam head acts on said   
     
     
        cam plate to radially reciprocate said cam plate and said master jaw. 8. A jaw chuck as in claim 7 and including: 
     
     
       a. a bushing around said bolt means and positioned in said slot. 9. A jaw chuck as in claim .[.2.]. .Iadd.1 .Iaddend.and including: a. spacer means having a thickness slightly greater than the thickness of said master jaws for maintaining an operating clearance between said work gripping members and said fixed portions and between said radially   
     
     
        reciprocable portion and said body member. 10. A jaw chuck as in claim 9 and wherein: a. said spacer means comprises a plurality of bolts positioned in spaces between said master jaws,   b. each of said bolts having an enlarged head portion, a shank portion, and a thread portion,   c. a bushing member having a thickness slightly greater than the thickness of said master jaws and positioned around said shank portion,   d. said thread portion threadedly engaging said body member, and   e. recesses formed in said work gripping members to provide working   
     
     
        clearance around said head portion. 11. A jaw chuck as in claim 6 and wherein: a. said leaf members, said fixed portions and said radially reciprocable   
     
     
        portions are all defined by slots provided in said master jaws. 12. A jaw chuck as in claim 11 and including: 
     
     
       a. three of said master jaws. 13. A master jaw for use in a reciprocating jaw chuck comprising: a. an element having a configuration generally of a truncated sector,   b. said element being symmetrical,   c. a first pair of slots of substantially equal length extending chordally inwardly from .[.said arc.]. .Iadd.the outer periphery of said truncated sector.Iaddend. ,   d. a second pair of slots of substantially equal length extending into said element substantially perpendicularly to said first slots and having terminal portions extending outwardly substantially parallel to said first slots,   e. said slots dividing said element into two spaced portions attachable to a chuck body and an intermediate portion movable with respect to said   
     
     
        spaced portions for supporting a work gripping jaw. 14. A master jaw as in claim 13 and wherein: a. said truncated sector is formed by two radii, an included arc, and a   
     
     
        chord intersecting said radii. 15. A master jaw as in claim 14 and wherein: a. said element is symmetrical with respect to a radial line bisecting the   
     
     
        angle between said two radii. 16. A master jaw as in claim 15 and wherein: 
     
     
       a. said first pair of slots are substantially parallel to said chord. 17. A master jaw as in claim 16 and wherein: a. said second pair of slots are substantially parallel to said radial line of symmetry.