SLEEVE RETENTION FOR CUTTING PICK ASSEMBLY
A cutting assembly is configured to be coupled to a drum that is rotatable about an axis. The cutting assembly includes a block having a leading surface and an inner surface. The inner surface forms a block bore extending along an axis through the leading surface and at least partially through the block. The cutting assembly also includes a sleeve having a sleeve shank with an outer surface, a flange, and a sleeve bore extending through the flange and at least partially through the sleeve shank. During installation of the sleeve to the block, an interface between the outer surface of the sleeve shank and the inner surface of the block bore transitions from an interference fit to a clearance fit.
This application claims priority to U.S. Provisional Patent Application No. 62/730,209, filed Sep. 12, 2018, the content of which is incorporated herein by reference.
BACKGROUNDThe present disclosure relates to bits or picks for cutting rock, and particularly to sleeve retention for a cutting pick assembly.
Cutting heads (e.g., for continuous mining and entry development machines) include multiple cutting pick assemblies. In some embodiments, each cutting pick assembly includes a holder block coupled to a rotating drum. The holder block includes a slot for receiving a sleeve. The sleeve in turn includes a bore for receiving a pick.
SUMMARYIn one independent aspect, a cutting assembly is configured to be coupled to a drum that is rotatable about an axis. The cutting assembly includes a block having a leading surface and an inner surface. The inner surface forms a block bore extending along an axis through the leading surface and at least partially through the block. The cutting assembly includes a sleeve having a sleeve shank with an outer surface, a flange, and a sleeve bore. The sleeve bore extends through the flange and at least partially through the sleeve shank. The sleeve shank is positionable within the block bore. The cutting assembly includes a step positioned on one of the inner surface of the block bore and the outer surface of the sleeve shank. The cutting assembly includes a protrusion positioned on the other of the inner surface of the block bore and the outer surface of the sleeve shank. The protrusion engages the step to maintain the sleeve shank within the block bore.
In another independent aspect, a cutting assembly is configured to be coupled to a drum that is rotatable about an axis. The cutting assembly includes a block having a leading surface and an inner surface. The inner surface forms a block bore extending along an axis through the leading surface and at least partially through the block. The cutting assembly also includes a sleeve having a sleeve shank with an outer surface, a flange, and a sleeve bore extending through the flange and at least partially through the sleeve shank. During installation of the sleeve to the block, an interface between the outer surface of the sleeve shank and the inner surface of the block bore transitions from an interference fit to a clearance fit.
In yet another independent aspect, a cutting assembly is configured to be coupled to a drum that is rotatable about an axis. The cutting assembly includes a block having a leading surface and an inner surface. The inner surface forms a block bore extending along an axis through the leading surface and at least partially through the block. The cutting assembly also includes a sleeve having a sleeve shank with an outer surface, a flange, and a sleeve bore extending through the flange and at least partially through the sleeve shank. The sleeve moves from a first position to a second position relative to the block during installation of the sleeve to the block. An interface between the outer surface of the sleeve shank and the inner surface of the block bore provides a compressive force on the sleeve shank when in the first position. The compressive force is decreased when in the second position.
Other aspects will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “mounted,” “connected” and “coupled” are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical or hydraulic connections or couplings, whether direct or indirect. Also, electronic communications and notifications may be performed using any known means including direct connections, wireless connections, etc. Terms of degree, such as “substantially,” “about,” “approximately,” etc. are understood by those of ordinary skill to refer to reasonable ranges outside of the given value, for example, general tolerances associated with manufacturing, assembly, and use of the described embodiments.
As shown in
Referring to
As shown in
As shown in
In the illustrated embodiment, the sleeve shank 106 further includes a third portion 132 positioned between the recess 126 and the flange 110 with respect to the bore axis 128, and the third portion 132 has a third outer diameter OD3. The third outer diameter OD3 is larger than the first outer diameter OD1. In other embodiments, the third outer diameter OD3 can be substantially equal to the first outer diameter OD1, or the third outer diameter OD3 can be less than the first outer diameter OD1. In addition, the outer surface 121 of the sleeve shank 106 includes a first step 133 (e.g., a first transition portion) between the sleeve protrusion 122 and the recess 126 along the axis 128 and a second step 135 (e.g., a second transition portion) between the recess 126 and the third portion 132 along the axis 128. In some embodiments, the recess 126 includes the first and second steps 133, 135. In further embodiments, the sleeve protrusion 122 includes the first step 133.
Referring again to
As best shown in
In the illustrated embodiment, the block bore 150 further includes a third portion 202 positioned between the block protrusion 198 and the leading surface 134, and the third portion 202 further includes a third inner diameter ID3. The third inner diameter ID3 is larger than the first inner diameter ID1. In other embodiments, the third inner diameter ID3 can be substantially equal to the first inner diameter ID1, or the third inner diameter ID3 can be less than the first inner diameter ID1. In addition, the inner surface 151 of the block bore 150 includes a third step 203 (e.g., a third transition portion) between the first portion 194 and the block protrusion 198 along the axis 128 and a fourth step 205 (e.g., a fourth transition portion) between the block protrusion 198 and the third portion 202 along the axis 128. In some embodiments, the block protrusion 198 includes the third and fourth steps 203, 205.
As shown in
With further insertion of the sleeve shank 106 into the block bore 150, the sleeve protrusion 122 slides past the block protrusion 198 to be received within the first portion 194 of the block bore 150 (
The clearance fit interface between the sleeve shank 106 and the block bore 150 when in the fully inserted position decreases the compressive force F acting on the sleeve shank 106 in the press-fit zone 206 (
Furthermore, the clearance fit interface between the sleeve shank 106 and the block bore 150 when in the fully inserted position allows for rotation of the sleeve shank 106 relative to the holder block 82. Such rotation of the sleeve shank 106—and ultimately the bit 74—relative to the holder block 82 facilitates wear on the bit 74 to be evenly distributed during operation of the machine 10.
Conventional blocks may be secured to a cutting drum by welding while a sleeve is positioned within the block bore in an interference fit or press fit (e.g., the sleeve is in compression while the inner surface of the block is in tension). However, heat generated by the welding process can be sufficient to relieve the residual stresses, thereby creating a fit or engagement that permits the sleeve to be easily dislodged from the block bore. In contrast, the sleeve shank 106 can only be inserted or extracted by passing through the press-fit zone 206, yet the sleeve shank 106 is not in a stressed condition in the fully installed position. As a result, heat will not relax the stresses and modify the engagement of the sleeve shank 106 and block bore 150. In some embodiments, the stress induced on the sleeve protrusion 122 of the sleeve shank 106 and the block protrusion 198 of the block bore 150 by the interference fit does not exceed the yield strength of the sleeve shank 106 or the block 82, thereby avoiding plastic deformation.
In other embodiments, the interfacing features between the sleeve 78 and the holder block 82 can be oriented in an opposite configuration. For example, at least one of the protrusion 122, the recess 126, the third portion 132, the first step 133, the second step 135, etc. can be formed on the holder block 82 and at least one of the first portion 194, the protrusion 198, the third portion 202, the third step 203, the fourth step 205, etc. can be formed on the sleeve 78.
Although the cutting bit assembly 66 has been described above with respect to a continuous mining machine 10, it is understood that the cutting bit assembly 66 could be incorporated onto various types of cutter heads and various types of mining machines.
Although aspects are described in detail above with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects as described. Various features and advantages of the invention are set forth in the following claims.
Claims
1. A cutting assembly configured to be coupled to a drum that is rotatable about an axis, the cutting assembly comprising:
- a block including a leading surface and an inner surface, the inner surface forming a block bore extending along an axis through the leading surface and at least partially through the block;
- a sleeve including a sleeve shank having an outer surface, a flange, and a sleeve bore, the sleeve bore extending through the flange and at least partially through the sleeve shank, the sleeve shank positionable within the block bore;
- a step positioned on one of the inner surface of the block bore and the outer surface of the sleeve shank; and
- a protrusion positioned on the other of the inner surface of the block bore and the outer surface of the sleeve shank, the protrusion engaging the step to maintain the sleeve shank within the block bore.
2. The cutting assembly of claim 1, wherein the protrusion is a sleeve protrusion positioned on the outer surface of the sleeve shank, wherein the inner surface of the block bore includes a block protrusion having the step, wherein the block protrusion includes an inner diameter and the sleeve protrusion includes an outer diameter, and wherein the outer diameter is greater than the inner diameter.
3. The cutting assembly of claim 2, wherein the sleeve protrusion slides past the block protrusion as an interference fit during installation of the sleeve to the block.
4. The cutting assembly of claim 3, wherein the sleeve forms a clearance fit with the block bore after the sleeve protrusion slidably engages the block protrusion.
5. The cutting assembly of claim 4, wherein the sleeve forms a clearance fit with the block bore before the sleeve protrusion slidably engages the block protrusion.
6. The cutting assembly of claim 1, wherein the protrusion is a sleeve protrusion positioned on the outer surface of the sleeve shank, wherein the inner surface of the block bore includes a block protrusion having the step, wherein the sleeve shank includes a recess positioned between the sleeve protrusion and the flange along the axis, and wherein the recess receives the block protrusion.
7. The cutting assembly of claim 6, wherein the inner surface of the block bore includes a portion, wherein the block protrusion is located between the portion and the leading surface along the axis, and wherein the portion receives the sleeve protrusion.
8. The cutting assembly of claim 1, wherein the inner surface of the block bore includes a block protrusion having the step, wherein the block protrusion includes a constant inner diameter along the axis.
9. The cutting assembly of claim 8, wherein the block protrusion angularly extends 360-degrees about the axis.
10. The cutting assembly of claim 1, wherein the protrusion is a sleeve protrusion positioned on the outer surface of the sleeve shank, wherein the sleeve protrusion includes a constant outer diameter along the axis.
11. The cutting assembly of claim 10, wherein the sleeve protrusion angularly extends 360-degrees about the axis.
12. The cutting assembly of claim 1, wherein the protrusion is a sleeve protrusion positioned on the outer surface of the sleeve shank, wherein the sleeve includes a notch extending through the sleeve protrusion, and wherein the notch enables resilient movement of the sleeve protrusion during installation of the sleeve to the block.
13. The cutting assembly of claim 1, further comprising a bit including a tip, a bit shank, and a shoulder position between the tip and the bit shank, wherein the bit shank is positioned within the sleeve bore, and wherein the shoulder abuts the flange of the sleeve.
14. A cutting assembly configured to be coupled to a drum that is rotatable about an axis, the cutting assembly comprising:
- a block including a leading surface and an inner surface, the inner surface forming a block bore extending along an axis through the leading surface and at least partially through the block; and
- a sleeve including a sleeve shank having an outer surface, a flange, and a sleeve bore extending through the flange and at least partially through the sleeve shank,
- wherein during installation of the sleeve to the block, an interface between the outer surface of the sleeve shank and the inner surface of the block bore transitions from an interference fit to a clearance fit.
15. The cutting assembly of claim 14, wherein the clearance fit allows for rotational movement of the sleeve relative to the block about the axis.
16. The cutting assembly of claim 14, wherein the inner surface of the block bore includes a block protrusion and the outer surface of the sleeve shank includes a sleeve protrusion, and wherein the interference fit includes engagement between the block protrusion and the sleeve protrusion.
17. The cutting assembly of claim 16, wherein the outer surface of the sleeve shank includes a recess positioned between the sleeve protrusion and the flange along the axis, and wherein the clearance fit includes the block protrusion received within the recess.
18. The cutting assembly of claim 17, wherein the inner surface of the block bore includes a portion, wherein the block protrusion is positioned between the portion and the leading surface along the axis, and wherein the clearance fit includes the sleeve protrusion received within the portion of the block bore.
19. The cutting assembly of claim 14, further comprising a bit including a tip, a bit shank, and a shoulder position between the tip and the bit shank, wherein the bit shank is positioned within the sleeve bore, and wherein the shoulder abuts the flange of the sleeve.
20. A cutting assembly configured to be coupled to a drum that is rotatable about an axis, the cutting assembly comprising:
- a block including a leading surface and an inner surface, the inner surface forming a block bore extending along an axis through the leading surface and at least partially through the block; and
- a sleeve including a sleeve shank having an outer surface, a flange, and a sleeve bore extending through the flange and at least partially through the sleeve shank,
- wherein the sleeve moves from a first position to a second position relative to the block during installation of the sleeve to the block, wherein an interface between the outer surface of the sleeve shank and the inner surface of the block bore provides a compressive force on the sleeve shank when in the first position, and wherein the compressive force is decreased when in the second position.
21. The cutting assembly of claim 20, wherein the inner surface of the block bore includes a block protrusion and the outer surface of the sleeve shank includes a sleeve protrusion, and wherein the compressive force is provided by engagement between the block protrusion and the sleeve protrusion.
22. The cutting assembly of claim 21, wherein the outer surface of the sleeve shank includes a recess positioned between the sleeve protrusion and the flange along the axis, and wherein the compressive force is decreased when the block protrusion is received within the recess.
23. The cutting assembly of claim 22, wherein the inner surface of the block bore includes a portion, wherein the block protrusion is located between the portion and the leading surface along the axis, and wherein the compressive force is decreased when the sleeve protrusion is received within the portion of the block bore.
24. The cutting assembly of claim 20, wherein the second position is a fully inserted position of the sleeve shank within the block bore.
Type: Application
Filed: Sep 12, 2019
Publication Date: Mar 12, 2020
Inventor: Christopher G. Stewart (Oil City, PA)
Application Number: 16/569,178