Patent Application
20080053711
Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or 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. Use of “including” and “comprising” and variations thereof as used herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Use of “consisting of” and variations thereof as used herein is meant to encompass only the items listed thereafter and equivalents thereof. Further, it is to be understood that such terms as “forward”, “rearward”, “left”, “right”, “upward” and “downward”, etc., are words of convenience in reference to the drawings and are not to be construed as limiting terms.
Referring now to the drawings wherein the showings are for purposes of illustrating the present preferred embodiments of the invention only and not for purposes of limiting same, the Figures show a mining machine cutting drum (not shown) which supports a cutting bit 12 by means of a bit holder 18.
As is well known in the art, the cutting drum (not shown) is supported by a mining machine (not shown) for rotation while being vertically moveable and while the mining machine advances forward. As is also well known, the cutting drum (not shown) typically includes a plurality of cutting bits 12 arranged thereon; however, the present description will now be directed to a single cutting bit 12 and the structure of a single present bit holder 18.
The bit holder 18 may be attached directly or indirectly to the drum 10. For example, the bit holder may be welded or clamped to the drum 10 or may be secured to a mounting block attached to the drum 10. As described hereinafter, the bit holder 18 receives and retains a sleeve 50 which rotatably receives the bit 12.
The cutting element or bit 12 includes a central cylindrical shank portion 24 and having an enlarged conical cutting portion or nose 26 attached thereto such that a shoulder area 28 is formed there between. The cutting bit has a central axis shown at 29 with a hard cutting tip 30 on one end of the cutting bit 12. The cutting bit 12 includes on its other end a recessed notch 32 and terminates in an end shoulder 34 such that a retaining ring (not shown) may be received within the notch 32 to prevent the axial removal of the cutting bit 12 from a sleeve 50. In other embodiments (not shown), the shoulder area 28 can be omitted.
The bit holder 18 has a body portion 38 and a base portion 40. The base portion 40 attaches directly to the cutting drum (not shown) or indirectly by means of a mounting block (not shown). The body portion 38, which is integral to the base portion 40, includes an aperture 42 for receiving a coaxial sleeve 50. The aperture 42 defines an inner surface 42a. The body portion 38 includes a contact face 44 which is shown as perpendicular to the longitudinal axis 46, which is the same as the central axis 29 of the aperture 42, but which may also be formed as a cone whose surface is at an angle with respect to the longitudinal axis 46 of the aperture 42.
The sleeve 50 has an elongated body member 52 and a collar 54, the collar 54 having an inside surface 56 and an outside surface 58. The inside surface 56 of the collar 54 abuts the contact face 44. The collar 54 is shown as having an inside surface 56 which is perpendicular to the longitudinal axis 46 of the aperture 42; however, the inside surface can be conical having a conical surface at an angle with respect to the longitudinal axis 46 corresponding to the angle of the contact face 44. The outside surface 58 of the collar 54 has a beveled surface 60 and a flat surface 62. The body member 52 of the sleeve 50 defines an outer surface 52a.
The body member 52 of the sleeve 50 has a bore 64 which is coaxial with the bit axis 29. The bit 12 is rotatably received by the bore 64. The shank 24 of the bit 12 is slightly smaller than the bore 64. The shank 24 is retained in the bore 64 by the retaining ring and the shank may rotate about the central axis 29 in order to avoid uneven wearing of the tip 30 of the cutting bit 12. The shoulder area 28 of the bit 12 abuts the flat surface 62 to position the bit 12 axially in the bore 64 and transmit cutting forces.
More particularly, as shown in
In the preferred embodiment, the inner core 86 is made of diamond, but in less preferred embodiments, a hardened form of tungsten carbide can be used. The diamond core 86 is a solid diamond, not a coated structure. Further, in the preferred embodiment, the inner core 86 is exposed at the outer end 90. The inner core 86 is made from a sheet of material, but in other embodiments (not shown), the inner core 86 may be cylindrical, or any other shape. Further, in an alternate embodiment, as shown in
Various other features and advantages of the invention will be apparent from the following claims.
| Number | Date | Country | |
|---|---|---|---|
| 60824563 | Sep 2006 | US |
