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.

Description

FIELD

The present disclosure relates to a sleeve for a block and sleeve assembly. In particular, the sleeve has a central bore with a rearwardly opening taper to allow rearward removal of a shank of a sheared cutting pick from the sleeve.

BACKGROUND

In the discussion of the background that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art.

Various different forms of equipment and machinery can be employed for mining and excavation operations. Typically, it is the type of mining or excavation taking place, and the type of earth being mined or excavated, that dictates the type of equipment and machinery that is appropriate. Commonly, equipment and machinery for such purposes include a cutting pick mounted on a rotating element either directly or via a block or via a block and sleeve assembly. In operation, the cutting picks rotate with the rotating element to impact against and to dislodge or fragment earth from the face being contacted. Cutting picks employed for the above purpose generally have a hard cemented tungsten carbide tip, which is fixed, usually by brazing, to a head of the cutting pick, and a steel shank. Cutting picks of this kind are disclosed in various publications, such as U.S. Pat. No. 6,113,195.

Sleeved block systems can be press-fit in openings in holder blocks. However, press-fitting makes removing and installing sleeves in the field very difficult and time consuming. Extreme force is often required to remove these sleeves from their holders. Hydraulic jacks are typically needed to perform this task. In some operating environments the use of hydraulic jacks or other equipment to remove press-fit sleeves is difficult and time-consuming.

As an alternative to press-fit systems, sleeve retaining methods have been used, such as clips, nuts or wedges in slots. Generally, nuts and wedges provide an advantageous biasing force to hold the sleeve in the opening. However, nuts are difficult to adjust and the slots for wedges increase manufacturing complexity and introduce a fracture generating hole in the shank of the sleeve. Clips have provided a size restriction to sleeve removal and are easily manipulated by a user, but have not generally provided a biasing force. A clip combining both a size restriction and a biasing force would be advantageous.

Another problem with existing sleeve designs is evident when an installed cutting pick breaks in the sleeve. Typically, it is the head of the cutting pick that shears off, leaving the shank in the bore of the sleeve. These broken pick shanks cannot easily, if at all, be removed in the field while the sleeve is in the block due to limited space behind the sleeve and/or due to compacted debris in the block and sleeve assembly or even in open portions of the sleeve bore. Therefore, the sleeve with a broken shank must first be removed from the block in order to remove the broken shank.

SUMMARY

An exemplary embodiment of a block and sleeve assembly comprises 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.

An exemplary embodiment of a hollow sleeve adapted to be mounted in a holder block and to receive a shank of a cutting pick comprises 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.

An exemplary embodiment of an assembly comprises a holder block, a hollow sleeve, and a cutting pick, wherein the hollow sleeve includes a shank portion, a head portion, and a shoulder portion, and a central bore extending rearwardly along a 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, 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, and wherein a shank of the cutting pick is inserted into the central bore of the hollow sleeve

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWING

The following detailed description can be read in connection with the accompanying drawings in which like numerals designate like elements and in which:

FIG. 1 is a cross-sectional view of an exemplary embodiment of a block and sleeve assembly.

FIG. 2 is another cross-sectional view of the exemplary embodiment of a block and sleeve assembly shown in FIG. 1.

FIG. 3 is a cross-sectional view of an exemplary embodiment of an assembly showing the position of a cutting pick when installed in the sleeve bore of a block and sleeve assembly.

FIG. 4 is a cross-sectional view of an exemplary embodiment of a block and sleeve assembly showing the rearward removal from the sleeve bore of the shank of a shorn cutting pick.

FIG. 5 is a schematic, isometric view of an exemplary embodiment of a block and sleeve assembly utilizing an exemplary embodiment of a retainer clip.

DETAILED DESCRIPTION

FIG. 1 is a cross-sectional view of an exemplary embodiment of a block and sleeve assembly. The illustrated block and sleeve assembly 2 comprises a holder block 10 and a hollow sleeve 30. The holder block 10 generally includes a base portion 12 and a body portion 14 and the hollow sleeve 30 generally includes a shank portion 32, a head portion 34, a shoulder portion 36, and a central bore 38.

The holder block 10 can be any suitable holder block. In an exemplary embodiment, the holder block 10 includes a first opening 16 extending longitudinally from a front face 18 of the body portion 14 to receive the shank portion 32 of the hollow sleeve 30. The illustrated example of a holder block is a bridge-type holder block and includes a second opening 20 extending from a first side edge 22 to a second side edge 24 and includes a bridge portion 26.

The hollow sleeve 30 can be any suitable hollow sleeve. In an exemplary embodiment, the central bore 38 of the hollow sleeve 30 extends rearwardly along the central axis A from a first opening 40 in a forwardmost surface 42 of the head portion 34 to a second opening 44 in a rearwardmost surface 46 of the shank portion 32. The central bore 38 has at least two portions, the first portion 48 located axially forward of the second portion 50. The first portion 48 has a surface located at a first radius R₁ and the second portion 50 has a surface with a rearwardly opening taper 52 terminating at the second opening 44. The second opening 44 has a second radius R₂, where the second radius R₂ is larger than the first radius R₁.

FIG. 2 is another cross-sectional view of the exemplary embodiment of a block and sleeve assembly shown in FIG. 1. FIG. 2, among other things, shows the relationships between the rearwardly opening taper 52 and other features of the holder block 10 and the hollow sleeve 30. For example, the rearwardly opening taper 52 has a first end 54 and a second end 56. The first end 54 has a smaller radius than the second end 56 and contacts the first portion 48 at a transition plane P. The second portion 50 of the central bore 38 is axially rearward of the shoulder portion 36, i.e., the transition plane P is axially rearward of the shoulder portion 36.

In another exemplary embodiment, 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 second opening in the holder block are sized to allow rearward removal of a shank of a sheared cutting pick from the sleeve. For example, an angle of the rearwardly opening taper is suitably sized to allow, singly or in combination with the distance from the beginning of the taper of the central bore of the sleeve to the surface of the side-to-side second opening in the holder block, rearward removal of the shorn shank. An example of a suitable angle θ of the rearwardly opening taper 52 is at least about (±10%) 10° relative to the central axis A. Alternatively, the angle θ is from about 10° to about 45°, alternatively about 10° to about 20°. In another example, a minimum distance from the first end 54 of the second portion 50 of the hollow sleeve 30 to a surface 58 of the second opening 20 in the holder block 10 is suitably sized to allow, singly or in combination with the angle of the rearwardly opening taper, rearward removal of the shorn shank. The minimal distance is measured along the surface of the rearwardly opening taper 52 and a rearward projection 52′ thereof. An example of a minimal distance is equal to or greater than an axial length L of the first portion 48 of the hollow sleeve 30.

The features and geometries of the central bore 38 can be manufactured by any suitable techniques. In an exemplary embodiment, the central bore 38 can be drilled or reamed, formed by other machining methods or forged.

Exemplary embodiments of the hollow sleeve optionally have at least a portion of an outer circumferential surface 60 of the shank portion 32 forwardly tapered, alternatively all of the outer circumferential surface of the shank portion is forwardly tapered. The angle θ of the forwardly tapered outer circumferential surface 60 is at least about (±10%) 2° to about 15° relative to the central axis A. Alternatively, the angle θ is about 5° to about 6° relative to the central axis A. A surface 28 of the first opening 16 in the holder block 10 is complementarily tapered to the forwardly tapered outer circumferential surface 60 of the shank portion 32. This taper provides optimal support by distributing the load through the holder block 10. Although this provides a tight fit between the hollow sleeve 30 and the holder block 10, the hollow sleeve can be easily dislodged, e.g., by a mallet strike or a tool puller.

As illustrated in the figures, the first opening 40 can include a flared or countersunk feature without impacting the operating principles of the block and sleeve assembly 2 disclosed here. Such a feature can accommodate, for example, a surface of the cutting pick or a washer associated therewith, as shown in FIG. 3. Likewise, the second opening 44 can also have a flared or countersunk feature.

FIGS. 3 and 4 illustrate a block and sleeve assembly 2 with a cutting pick 100 installed therein. A rearwardmost end 102 of the shank 104 of the cutting pick 100 is positioned within the first portion 48 of the central bore 38. Alternatively, the rearwardmost end 102 of the shank 104 can be co-terminus with the first end 54 of the second portion 50. During use, all or a portion of a head portion 106 or a head portion 106 and a shoulder portion 108 of the cutting pick 100 can be shorn off, leaving the shank 104 installed in the central bore 38 of the hollow sleeve 30. Removing the shorn shank 110 can be time consuming or difficult, even requiring removal of the sleeve before clearing of the bore can be accomplished. In addition, the second opening 20 in the holder block 10 and the second portion 50 of the central bore 38, e.g., the portion of the central bore 38 not occupied by a properly installed cutting pick 100, collects compacted debris from operations. This compacted debris further complicates the removal of the shorn shank 110 by requiring the compacted debris to be cleared before access is gained to the rearwardmost surface 46 of the shank portion 32 of the hollow sleeve 30 and to the rearwardmost end 102 of the shank 104 of the cutting pick 100.

FIG. 4 illustrates an example of removal of a shorn cutting pick shank. In the instant case, the sizing of the rearwardly opening taper 52 and/or the minimum distance from the first end 54 of the second portion 50 of the hollow sleeve 30 to a surface 58 of the second opening 20 in the holder block 10 allows the shorn cutting pick shank 110 to be driven rearwardly and out of the central bore 38. Driving of the shorn cutting pick shank 110 can be by any suitable means, such as by a punch and hammer. The shorn shank 110, in addition to being driven rearward, can be angled within the rearwardly opening taper 52 of the hollow sleeve 30 and within the second opening 20 in the holder block 10 to facilitate removal.

To provide sufficient retention of the hollow sleeve 30 in the holder block 10, a retainer can be used. An exemplary retainer 120 is shown in FIG. 5, which also illustrates the retainer 120 installed in a retainer groove 122. The retainer 120 snaps into the groove 122 at the rear of the shank portion 32 of the sleeve 30 (see, e.g., FIG. 1) and provides a force, urging the sleeve 30 rearward relative to the holder block 10 and into the first opening 16 of the holder block 10. In an exemplary embodiment, the retainer 120 is made from spring steel with a curved profile. When installed, the curved profile is positioned with the concave portion oriented forwardly. The retainer 120 has a tab 124 with a slot 126 to assist with removal of the retainer 120 from the groove 122.

In exemplary embodiments, the base portion 12 of the holder block 10 is adapted for mounting on a rotatable element of a machine for mining, excavating, tunneling, road planing and/or construction (not shown), such as an Alpine Miner mining machine available from Sandvik AB. The holder block 10 has a large footprint providing ample weld surface area. It also has locating holes 130 in the base portion 12 (see, e.g., FIG. 1), which can be used for easy alignment onto the machine.

The sleeve disclosed herein, and any associated holder block, can also incorporate rotation inhibiting cooperating features. An example of rotation inhibiting cooperating features includes a polygon-shaped shoulder region of the sleeve that provides a flat, which contacts a corresponding surface of a stop on the block to prevent or limit rotation of the sleeve. The polygon-shaped head region of the sleeve is also optionally inscribed within the shoulder of the pick, or washer if used, which facilitates pick removal. Such cooperating features and optional head region inscribed within the cutting pick shoulder are disclosed in U.S. Patent Application No. 61/053,268, entitled “BLOCK AND SLEEVE WITH ROTATION-INHIBITING FEATURE”, filed on May 15, 2008, the entire contents of which are incorporated herein by reference.

Although described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without department from the spirit and scope of the invention as defined in the appended claims.

Claims

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.