Sleeve with widening taper at rearward end of bore

Abstract

A block and sleeve assembly and a sleeve per se are disclosed. The sleeve has a central bore with a rearwardly opening taper. The holder block has a side-to-side opening with a bridge. An angle of the rearwardly opening taper and/or the distance from the beginning of the taper of the central bore of the sleeve to the surface of the side-to-side opening are sized to allow rearward removal of a shank of a sheared cutting pick from the sleeve. Optionally, an outer circumferential surface of at least a portion of the sleeve shank is forwardly tapered and the opening in the holder block is complementarily tapered to receive the sleeve shank. A rearward biasing retainer clip can also optionally be included.

1 . A block and sleeve assembly, comprising:
 a holder block; and   a hollow sleeve,   wherein the hollow sleeve includes a shank portion, a head portion, and a shoulder portion, and a central bore extending rearwardly along the central axis from a first opening in a forwardmost surface of the head portion to a second opening in a rearwardmost surface of the shank portion,   wherein the central bore has at least two portions, a first portion of the central bore has a surface located at a first radius and a second portion of the central bore has a surface with a rearwardly opening taper, and the first portion is axially forward of the second portion, and   wherein the holder block comprises a base portion and a body portion, a first opening extending longitudinally from a front face of the body portion to receive the shank portion of the hollow sleeve, a second opening extending from a first side edge to a second side edge, and a bridge portion.   
     
     
         2 . The block and sleeve assembly of  claim 1 , wherein the rearwardly opening taper has a first end and a second end, the first end has a smaller radius than the second end, and the first end contacts the first portion. 
     
     
         3 . The block and sleeve assembly according to  claim 1  or  2   claim 1 , wherein an angle of the rearwardly opening taper is at least 10° relative to the central axis. 
     
     
         4 . The block and sleeve assembly as in,  claim 1 , wherein the second portion of the central bore is axially rearward of the shoulder portion. 
     
     
         5 . The block and sleeve assembly as in  claim 1 , wherein at least a portion of an outer circumferential surface of the shank portion is forwardly tapered. 
     
     
         6 . The block and sleeve assembly of  claim 5 , wherein an angle of the forwardly tapered outer circumferential surface of the shank portion is at least about 2° to about 15° relative to the central axis. 
     
     
         7 . The block and sleeve assembly as in  claim 1 , wherein a minimum distance from the first end of the second portion of the hollow sleeve to a surface of the second opening in the holder block is equal to or greater than an axial length of the first portion of the hollow sleeve. 
     
     
         8 . The block and sleeve assembly of  claim 7 , wherein the minimum distance is measured along the surface of the rearwardly tapered section and a rearward projection thereof. 
     
     
         9 . The block and sleeve assembly as in  claim 1 , comprising a retainer groove in an outer circumferential surface of the shank portion and comprising a clip inserted into the retainer groove and biasing the hollow sleeve rearward relative to the holder block. 
     
     
         10 . A hollow sleeve adapted to be mounted in a holder block and to receive a shank of a cutting pick, the hollow sleeve comprising:
 a shank portion;   a head portion; and   a shoulder portion,   wherein the shank portion, head portion and shoulder portion are arranged longitudinal along a central axis with the shoulder portion separating the shank portion from the head portion,   wherein a central bore extends rearwardly along the central axis from a first opening in a forwardmost surface of the head portion to a second opening in a rearwardmost surface of the shank portion, and   wherein the central bore has at least two portions, a first portion of the central bore has a surface located at a first radius and a second portion of the central bore has a surface with a rearwardly opening taper, and the first portion is axially forward of the second portion.   
     
     
         11 . The hollow sleeve of  claim 10 , wherein the rearwardly opening taper has a first end and a second end, the first end has a smaller radius than the second end, and the first end contacts the first portion. 
     
     
         12 . The hollow sleeve according to  claim 10 , wherein an angle of the rearwardly opening taper is at least 10° relative to the central axis. 
     
     
         13 . The hollow sleeve as in  claim 10 , wherein the second portion of the central bore is axially rearward of the shoulder portion. 
     
     
         14 . The hollow sleeve as in  claim 10 , wherein at least a portion of an outer circumferential surface of the shank portion is forwardly tapered. 
     
     
         15 . A machine for mining, excavating, tunneling, road planing and/or construction, comprising:
 a rotatable element; and   the block and sleeve assembly as in  claim 1  mounted on the rotatable element.