Holder block assembly with mechanical extraction device

Abstract

A holder block assembly for a drum-type cutting tool has a holder block and a sleeve that is removably held in the holder block to carry a cutter bit. The sleeve includes a shank received in a hole in a cutter block and a nut threaded on the shank. The nut is turned by a hand tool to extract the sleeve from the holder block.

Claims

1. A holder block assembly for holding a cutter bit, the holder block assembly comprising: a holder block, a sleeve removably holdable in the holder block, and a mechanical extraction system operable to remove the sleeve when held by the holder block from the holder block; the holder block comprising a hole extending along an axis, and a hole wall surrounding the hole; the sleeve extending along the axis between opposite first and second ends, the sleeve comprising a hole opening from the first end of the sleeve and a shank disposed at the second end of the sleeve, a first portion of the shank being receivable in the hole of the holder block; the mechanical extraction system comprising a nut and a second portion of the shank, the second portion of the shank being externally threaded and being disposed between the first end of the sleeve and the first portion of the shank, the nut being threadable on the second portion of the shank to form a threaded connection between the nut and the second portion of the shank, the nut being rotatable about the threaded connection and thereby axially movable along the threaded connection between a first axial position closest to the first end of the sleeve and a second axial position spaced away from the first axial position; and the nut when threaded on the second shank portion and in the first position is abuttable against the holder block and thereby resists further insertion of the shank into the holder block hole when the first shank portion is received in the holder block hole, the holder block wall and the first portion of the shank cooperatively forming a connection therebetween when the first shank portion is inserted into the holder block hole that resists axial displacement of the first shank portion out of the holder block hole.

2. The holder block assembly of claim 1 wherein the sleeve comprises a radially enlarged flange disposed at the first end of the sleeve, the shank extending from the flange to the second end of the sleeve.

3. The holder block assembly of claim 2 wherein the nut abuts the flange when the nut is in the first position.

4. The holder block assembly of claim 1 wherein the connection between the holder block hole wall and the first shank portion comprises at least one interference fit therebetween.

5. The holder block assembly of claim 1 wherein the first portion of the shank tapers inwardly as the first portion of the shank extends towards the second end of the sleeve.

6. The holder block assembly of claim 1 wherein the first portion of the shank and the holder block hole wall each have a forward end and a plurality of axially adjacent surface sections that each have an axial length and become successively smaller in cross-section in a direction away from the forward end, and the connection between the first portion of the shank and the holder block hole wall comprises respective interference fits between facing pairs of surface sections.

7. A cutting drum comprising a plurality of holder block assemblies as defined in claim 1.

8. A mining machine comprising the cutting drum defined in claim 7.

9. A method of extracting a sleeve held in the hole of the holder block assembly of claim 1, the sleeve being configured to hold a cutter bit, the method comprising the steps of: (a) providing the nut threaded on the sleeve, the nut threadably movable in a first direction towards the holder block whereby the nut would engage the holder block and transmit a force to the sleeve urging the nut away from the holder block and the sleeve out of the holder block hole; and (b) applying a torque to the nut urging the nut against the holder block, the torque generating sufficient force transmitted to the sleeve to move the sleeve away from the holder block; and (c) continuing to apply torque to the nut urging the nut against the holder block until the sleeve moves out of the holder block a sufficient distance to release the sleeve from the holder block.

10. The method of claim 9 wherein the sleeve is held in the holder block by at least one interference fit, and step (b) comprises the step of: (d) transmitting a sufficient force to the sleeve sufficient to overcome resistance of the at least one interference fit.

11. The method of claim 10 wherein a portion of the sleeve is in the holder block hole when the sleeve is released from the holder block.

12. The method of claim 9 wherein the nut abuts the holder block when the sleeve is retained by the holder block.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a depiction of an earth working operation including a drum with holder block assemblies in accordance with this disclosure attached to a support of a mining machine.

(2) FIG. 2 is a vertical sectional view of a holder block assembly shown in FIG. 1.

(3) FIG. 3 is a front view of the holder block of the holder block assembly shown in FIG. 2.

(4) FIG. 4 is a sectional view of the sleeve shown in FIG. 3 taken along line 4-4 of FIG. 3.

(5) FIG. 5 is a front view of the sleeve of the holder block assembly shown in FIG. 2.

(6) FIG. 6 is a vertical sectional view of the sleeve shown in FIG. 5.

(7) FIG. 7 is a top view of the nut of the holder block assembly shown in FIG. 2.

(8) FIG. 8 is a sectional view of the nut shown in FIG. 7 taken along line 8-8 of FIG. 7.

(9) FIGS. 9 and 10 are front and side views respectively of a spanner wrench for applying torque to the nut shown in FIG. 7.

DETAILED DESCRIPTION

(10) FIG. 1 illustrates a number of like holder block assemblies 10 in accordance with this disclosure mounted on the outer periphery of a cutting drum D of a mining machine M used in coal mining. The cutting drum rotates to impact cutter bits carried by the holder block assemblies against a coal seam or earthen material C.

(11) FIG. 2 is a sectional view of one of the holder block assemblies 10. The holder block assembly is shown carrying a conventional cutter bit 12. The holder block assembly includes a holder block 14 that mounts the assembly to the drum D and removably carries a sleeve 16. The sleeve removably carries the cutter bit 12. The holder block assembly includes a mechanical extraction system in which a nut 20 threaded on the sleeve, the nut enabling removal of the sleeve from the holder block using a simple hand tool as explained in more detail below.

(12) The holder block 14 is illustrated in FIGS. 3 and 4. The holder block has a curved lower wall surface 22 that mounts the holder block to the cutting drum D. A flat outer peripheral wall surface 24 faces towards the intended cutting direction of the cutter bit. A through hole 26 extends from the outer surface 24 and into the holder block along an axis 28 that is perpendicular to the outer surface. The through hole is defined by an annular hole wall 30. The hole wall includes a number of axially adjacent, circular surface sections 32 that have a common axial length and become successively smaller in diameter in a direction extending axially away from the outer wall surface 24.

(13) The sleeve 16 is illustrated in FIGS. 5 and 6. The sleeve extends along a central axis 50. An enlarged head or flange 52 is located on one end of the sleeve. A reduced-diameter shank 54 extends axially from the flange to an opposite end of the sleeve. A central through-hole 56 extends the length of the sleeve and is sized to receive the cutter bit 12.

(14) The flange 52 has a generally flat rear shoulder or rear surface 58 surrounding the shank 54 that is perpendicular to the axis 50. The rear surface faces towards the opposite end of the sleeve.

(15) The shank 54 includes an externally threaded, circular shank portion 60 adjacent to the flange 52 and a tapered shank portion 62 extending away from the threaded shank portion to the opposite end of the sleeve. The shank may also include a stress relief undercut located between the flange and the threaded shank portion.

(16) The tapered shank portion 62 includes a number of axially adjacent, circular outer surface sections 64. The outer circular sections 64 have a common axial length and become successively smaller in diameter in a direction extending axially away from flange 52.

(17) The tapered shank portion 62 also includes a first O-ring groove 66 adjacent to the threaded shank portion 60 and a second O-ring groove 68 adjacent to the other end of the sleeve 16. The O-ring grooves receive O-rings that form seals between the sleeve and the holder block 14 when the sleeve is received in the holder block.

(18) The nut 20 is illustrated in FIGS. 7 and 8. The nut is a generally circularly cylindrical metal body having a length dimension 70 and an internally threaded through bore 72. The internal threads of the nut are sized to be threadable with the external threads of the sleeve 16. The nut can receive the tapered shank portion 54 of the sleeve to enable the nut to be threadably attached to the sleeve as shown in FIG. 2.

(19) Equally spaced around the outer periphery of the nut 20 are four like blind holes 74. The blind holes are used in cooperation with a spanner wrench described below to apply torque to the nut. In other embodiments the nut can be configured as a hex nut intended to be used with an open end wrench.

(20) FIGS. 9 and 10 illustrate a spanner wrench 80 for turning the nut 20. The wrench includes an open end 82 that receives the nut and an elongate handle 84 extending from the open end. A pair of pins or lugs 86 extends from the open end. The pins are spaced 90 degrees from one another and are received in respective blind holes 74 of the nut to form a non-rotatable connection between the wrench and the nut.

(21) FIG. 2 illustrates the sleeve 16 being held by the holder block 14. The nut 20 is threaded onto the sleeve shank threaded portion 60 and tightened against the flange surface 58 before the shank 54 is driven into the holder block hole 26. My '148 patent describes driving the sleeve shank into the holder block to form interference fits between corresponding surfaces 64, 30 of the sleeve shank and holder block, and so insertion of the sleeve into the holder block will not be discussed in detail herein.

(22) The nut 20 is larger than the holder block hole and so the nut is sandwiched between the sleeve flange and the holder block when the sleeve shank is fully received into the holder block. The length dimension 70 of the nut establishes the maximum depth of insertion of the sleeve shank into the holder block to form the interference fits between the shank and the holder block when the sleeve shank is fully driven into the holder block.

(23) The nut 20 and the threaded shank portion 60 cooperatively form a mechanical extraction system that enables mechanical extraction of the sleeve from the holder block.

(24) To extract the sleeve from the holder block, the nut 20 is rotated by applying torque to the nut so that the cooperating threads of the nut and shank sleeve urge the nut towards the holder block 14. The applied torque generates an axial force urging the sleeve away from the holder block with sufficient force to overcome the resistance to axial movement of the sleeve shank relative to the holder block generated by the interference fits between the sleeve shank and the holder block. Rotation of the nut displaces the sleeve axially away from the holder block. The nut has to rotate only enough for the sleeve to displace relative to the holder block the axial length of a surface section as previously described for the sleeve shank to be free of the holder block.

(25) While one or more embodiments have been disclosed and described in detail, it is understood that this is capable of modification and that the scope of the disclosure is not limited to the precise details set forth but includes modifications obvious to a person of ordinary skill in possession of this disclosure, including (but not limited to) changes in material selection, size, shape, or configuration and also such changes and alterations as fall within the purview of the following claims.