Patent Application
20160032722
The present invention relates to an apparatus for performing cutting operations by a mining machine and the method of making the apparatus.
Cutting chains are frequently found in mining operations, including in continuous longwall miners. These chains have tool bits mounted to them that act as picks to repeatedly break apart the surface being mined as the chain is driven around a sprocket.
Although mining chains are well known in the prior art, previously known mining chains are prone to failure due to breakage rather than normal wear. Often, the point of failure in a cutting link occurs at spots that have been welded, especially where the tool bit holder attaches to the link body. Due to the repeated stress of the mining bits on the hard mining material, the welded locations can eventually break or fracture, thus causing the chain to fail. The structure and operation of a continuous miner and the cutting chain for mining machines is set forth in detail in U.S. Pat. No. 5,031,964, and is herein incorporated by reference for all that it teaches.
As can be seen from the prior art depicted in
However, as our own analysis has shown, the weld of the tool bit holder to the chain link is often the point of weakness.
Prior cutting links that were cast instead of welded were unable to provide a strong link having the necessary features for modern mining chains. U.S. Pat. No. 3,968,995 also depicts a cutter link of a mining chain that includes a tool mounting hub that could either be welded or be integrally cast. However, this prior art cutting link employed an expanding ring around the shank of the tool bit that secured the shank within the mounting hub, making it difficult to replace.
Another prior art cutting link is depicted in
Another frequent area for failure of the mining chain occurs in the connection between links. The links of a mining chain are connected together by drive pins. However, the retention system for the drive pin uses dowel pins that can shear or break from lateral force or contact with the mining material. When this occurs, the chain breaks and the miner fails.
The breakage of the chains results in significant downtime and loss of productivity as the continuous longwall miner can no longer function until the chains are repaired or replaced. We further disclose herein a drive pin retention mechanism that does not suffer from the problems of the prior art.
We disclose herein a new link that is stronger than those described in the prior art. The claimed link does not employ welding to attach the tool bit holder, but instead is integrally cast as one piece. The cast link does not suffer the common failure at the weld and provides a much stronger link because you can put additional steel at the points you need it to give strength.
The disclosed link also employs the use of a rubber sandwich pin or steel spring pin with a drive pin retainer that covers the rubber or steel pin to provide a superior retention system for the pin in the retainer thereby doing a better job of retaining the retainer on the drive pin.
Further advantages of the invention will become apparent by reference to the detailed description of preferred embodiments when considered in conjunction with the drawings:
The following detailed description is presented to enable any person skilled in the art to make and use the invention. For purposes of explanation, specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that these specific details are not required to practice the invention. Descriptions of specific applications are provided only as representative examples. Various modifications to the preferred embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. The present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest possible scope consistent with the principles and features disclosed herein.
As will be also appreciated from
The cutting link 400 is designed to resemble other roller links found in the mining chain. It is comprised of a link body 401 that has a two transverse bores 410 at the longitudinal ends of the link body 401, wherein each of the transverse bores 410 can accept a drive pin 840 (also called a pivot pin) to pivotally connect the cutting links 400 to other roller links in the mining chain. The leading transverse bore 410 is on the side of the cutting link 400 that approaches the surface being mined first when in normal use, with the trailing transverse bore 412 residing on the trailing side of the cutting link 400 and last to approach the mining surface. In a preferred embodiment, the roller links may be carburized as to harden the metal.
An outwardly projecting tool mounting hub 420 extends from the link body 401 and has within it an open bore 422 through its length that is sized to snugly receive the shank 26 of a tool bit 25 (as pictured in
It should be appreciated that the tool mounting hub 420 may be angled to the left or right if it is a clearance bit intended to cut the kerf. The cutting tool bits depicted in
In a preferred embodiment, the upper surface of the tool mounting hub 420 is connected to the trailing end of the link body 401 by a curved convex surface. This rigid section of metal provides additional support and structure to the cutting link 400 so that impact forces on the tool bit 25 during mining are distributed throughout the whole cutting link 400, thus reducing stress on the tool mounting hub 420.
As can be seen in
The cutting link 400 is made by casting it as one single piece and does not have any welds holding it together. As a result, it is a much stronger link. Where required, the cast can be constructed to add additional steel in areas that require greater strength, creating a cutting link that is as strong as any other link in the chain.
It should be appreciated that the integral casting is much cheaper to make than forging and welding a link. Although an integral link having a tool mounting hub could be forged, it would require extensive drilling and machining to create the tool mounting hub and broaching to create the shank access gap.
Another point of failure in mining chains of the prior art is in the retention mechanism that holds the drive pins 840 (also known as pivot pins) in place. The drive pin 840 is a generally cylindrically-shaped pin that passes through the transverse bores 410 of the mining chain links. It has a pin head 842 on one end and a fastener end 844 at the opposite end.
Often, in the prior art, the drive pin 840 was held in place by a retainer 850 that surrounds the fastener end 844 of the drive pin 840. A dowel pin was driven through a hole in retainer 850, and through drive pin hole 848 in the side of the drive pin 840. The dowel pin protruded through the retainer 850, and could easily shear or break from the lateral force or contact with the mining material. When this occurs, the mining chain would break, and the miner fails. Some prior art roller links had protective rings surrounding the retainer that was intended to contain the dowel pin in its location. However, this protective ring could break off, and because there is no positive retention holding the dowel pin in, it could slide out.
In the presently disclosed invention, the pivot pin has a retainer 850 held on by pins that are substantially flush with the retainer. In one embodiment, such as depicted in
In another embodiment, as shown in
Because this rubber sandwich pin 860 or steel spring pin 870 does not substantially protrude past the retainer, there is a significantly reduced chance that either pin will become damaged resulting in the retainer 850 separating from the drive pin 840.
Other potential retainers and dowel pins are shown in
The presently disclosed drive pin retention system can be used with any shaped retainer 850 that fits over the fastener end 844 of the drive pin 840. In one embodiment, a D-shaped retainer is used in applications where the drive pin has at least one flat surface cut into the curved sidewall of the drive pin. In another embodiment, the drive pin 840 can be threaded such that the retainer 850 screws into place. Once the holes in the retainer and the drive pin hole 848 are aligned, a rubber sandwich pin or steel spring pin can be placed into the hole.
As will be appreciated from FIG. 18(A)-(D), the notched dowel pin 880 is held in place by two retainer rings 882 located in the holes of the drive pin 840. Each of the two retainer rings 882 acts individually as a lock to keep the dowel pin 880 in place. The double locking mechanism ensures that the dowel pin 880 stays in place, even if one retainer ring 882 fails.
To operate this drive pin retention system, the retainer 850 is placed over the end of the drive pin 840 such that the holes of the retainer 850 line up with the holes of the drive pin 840. The dowel pin 880 is then hammered through the first hole of the retainer 850 and to the first hole of drive pin 840 which has a retainer ring 882 against its opening, held in place by the plastic seal 884. The hammering of the dowel pin 880 causes the retainer ring 882 to open up as the dowel pin 880 is squeezed through. As the hammering continues, the dowel pin 880 will then pass through the second retainer ring 882 causing it to open up. As the leading notch of the dowel pin 880 passes through the second retainer ring 882, the retainer 850 closes around the leading dowel pin notch. The first retainer ring 882 will then also close around the trailing notch. Thus, each retaining ring 882 will be wrapped tightly in a closed position around the notches of the dowel pin 880.
It should be appreciated that the cutting link 400 and the pin retention mechanism does not require a whole new mining chain, but instead can be employed by replacing specific links or the retainer cap. Furthermore, although the invention has been described for use with mining, it can be used in other applications, such as trencher chains. The pin retention system can also be used in any chain application.
The terms “comprising,” “including,” and “having,” as used in the claims and specification herein, shall be considered as indicating an open group that may include other elements not specified. The terms “a,” “an,” and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The term “one” or “single” may be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as “two,” may be used when a specific number of things is intended. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.
The invention has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention. It will be apparent to one of ordinary skill in the art that methods, devices, device elements, materials, procedures and techniques other than those specifically described herein can be applied to the practice of the invention as broadly disclosed herein without resort to undue experimentation. All art-known functional equivalents of methods, devices, device elements, materials, procedures and techniques described herein are intended to be encompassed by this invention. Whenever a range is disclosed, all subranges and individual values are intended to be encompassed. This invention is not to be limited by the embodiments disclosed, including any shown in the drawings or exemplified in the specification, which are given by way of example and not of limitation.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
All references throughout this application, for example patent documents including issued or granted patents or equivalents, patent application publications, and non-patent literature documents or other source material, are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in the present application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).
| Number | Date | Country | |
|---|---|---|---|
| 62030893 | Jul 2014 | US |
