Pick-type mining bit with support block having rotatable seat

Abstract

A pick type mining bit with a cylindrical shank has a support block with a bore and a hard insert detachably and rotatably mounted in the bore. The insert has a bore for rotatably receiving the shank of the bit. The bit has a cylindrical working end projecting from the support block which tapers in at the tip and has a hard insert mounted in the tip. .Iadd.

What is claimed is:  .[.1. In combination; a none rotatable support block having a bore, a sleeve of hard wear resistant material rotatably mounted in said bore, first means retaining said sleeve in said bore while permitting rotation of the sleeve in the bore, a pick type bit having a cylindrical shank at one end and tapering in at the other end to a point, said shank being receivable in one end of said sleeve and being rotatable therein, second means detachably retaining said shank in said sleeve while permitting rotation of the shank in the sleeve whereby rotation of said bit can occur during working either with or without rotation of said sleeve, and said sleeve and support block having interengaging shoulders thereon for sustaining axial thrusts imposed on said sleeve by said bit during working operations, the said shoulder on said sleeve facing away from the said one end of the sleeve..]. .[.2. The combination according to claim 1 wherein said bore in said support block has a larger end part nearest the bit and a smaller end part remote from the bit, and the said shoulder on the block is at the juncture of said parts of said bore, and said sleeve has a larger end part nearest the bit and a smaller end part remote from the bit, rotatably fitting the larger and smaller end parts respectively of said bore, the shoulder on the sleeve being formed at the 
     
        juncture of the respective end parts thereof..]. 3. The combination according to claim .[.2.]. .Iadd.19 .Iaddend.in which said shoulders taper 
     
     
        outwardly toward the bit end of said sleeve. 4. The combination according to claim 3 in which the smaller end part of said sleeve projects beyond said block and said first means is mounted on the projecting portion of 
     
     
        said smaller end part of the sleeve outside said block. 5. The combination according to claim 3 in which said bit comprises a flared seat at the juncture of the shank of the bit with the other end of the bit, said 
     
     
        sleeve having a flared region engaged by said seat. 6. The combination according to claim 4 in which said sleeve has an integral groove past which said shank extends when the bit is mounted in the sleeve, and keeper means engaging the shank and groove and releasably retaining the shank in 
     
     
        the sleeve. 7. The combination according to claim 6 in which said keeper means is resilient so that the bit can be pried out of the sleeve and 
     
     
        forced into the sleeve. 8. The combination according to claim 7 in which said shank has an annular recess and said keeper means is mounted in the 
     
     
        recess and is captive on said shank. 9. The combination according to claim 8 in which said keeper means is in the form of a spring band. .Iadd. 10. The combination according to claim 19 in which said cylindrical shank of said bit is partially axially coextensive with the bore in said support block. .Iaddend. .Iadd. 11. The combination according to claim 18 in which said shoulders taper outwardly toward the bit end of said sleeve. .Iaddend..Iadd. 12. The combination according to claim 11 in which the smaller end part of said sleeve projects beyond said block and said first means is mounted on the projecting portion of said smaller end part of the sleeve outside said block. .Iaddend..Iadd. 13. The combination according to claim 11 in which said bit comprises a flared seat at the juncture of the shank of the bit with the other end of the bit, said sleeve having a flared region engaged by said seat. .Iaddend..Iadd. 14. The combination according to claim 12 in which said sleeve has an integral groove past which said shank extends when the bit is mounted in the sleeve, and keeper means engaging the shank and groove and releasably retaining the shank in the sleeve. .Iaddend..Iadd. 15. The combination according to claim 14 in which said keeper means is resilient so that the bit can be pried out of the sleeve and forced into the sleeve. .Iaddend..Iadd. 16. The combination according to claim 15 in which said shank has an annular recess and said keeper means is mounted in the recess and is captive on said shank. .Iaddend..Iadd. 17. The combination according to claim 16 in which said keeper means is in the form of a spring band. .Iaddend. .Iadd. 18. In combination: a non-rotatable support block having a bore; a sleeve of hard wear resistant material rotatably mounted in said bore; and a pick type bit having a shank rotatably receivable in one end of said sleeve; first means retaining said sleeve in said bore while permitting rotation of the sleeve in the bore; and second means detachably retaining said shank in said sleeve while permitting rotation of the shank in the sleeve so that rotation can occur both with and without rotation of said sleeve; said bore having a larger end part nearest the bit and a smaller end part remote from the bit; and a shoulder formed on the block at the juncture of said parts of said bore; said sleeve having a larger end part nearest the bit and a smaller end part remote from the bit and a shoulder, facing away from said one end of said sleeve, formed at the juncture of the respective end parts of the sleeve; said sleeve rotatably fitting the larger and smaller end parts respectively of said bore; said bit having a cylindrical shank at one end and tapering in at the other end to a point with said shank in said sleeve being partially axially coextensive with said bore in said support block; cooperating elements of abutment means between said sleeve and said bit; and said shoulders on said sleeve and said support block interengaging one another for sustaining axial thrusts imposed on said sleeve by said bit during working operations. .Iadd. 19. In combination: a non-rotatable support block having a bore; a sleeve of hard wear resistant material rotatably mounted in said bore; and a pick type bit having a shank rotatably receivable in one end of said sleeve; first means retaining said sleeve in said bore while permitting rotation of the sleeve in the bore; and second means detachably retaining said shank in said sleeve while permitting rotation of the shank in the sleeve so that rotation can occur both with and without rotation of said sleeve; said bore having a larger end part nearest the bit and a smaller end part remote from the bit; and a shoulder formed on the block at the juncture of said parts of said bore; said sleeve having a larger end part nearest the bit and a smaller end part remote from the bit and a shoulder facing away from said one end of said sleeve formed at the juncture of the respective end parts of the sleeve; said sleeve rotatably fitting the larger and smaller end parts respectively of said bore; said bit having a cylindrical shank at one end and tapering in at the other end to a point and said shoulders on said sleeve and said support block interengaging one another for sustaining axial thrusts imposed on said sleeve by said bit during working operations. .Iaddend.