Patent Application
20100052406
The present invention relates to tools and tool assemblies for mining and construction applications and, more particularly, is concerned with prolonging the life of the cutting tools in these applications.
Cutting tool assemblies for such applications as mining or road milling typically comprise a cutting tool, rotatably mounted within a support block. The support block in turn is mounted onto a drum, chain or other body, typically by welding, which in turn is driven by a suitable drive means. A number of such support blocks carrying cutting tools are mounted onto said drum to continually mine and remove material such as coal, rock, asphalt or concrete. The material removed by the cutting tool is pulverized by the cutting tool as each tip is rotated about the drum or chain into contact with the material. Some of the pulverized material collides against the support block and other cutting tool structure. The continual collision of cutting pick and material being removed causes abrasion and wear of the cutting tool and any other components mounted on or near the support block. The wear leads to eventual failure of the tool necessitating downtime of the associated equipment so the worn parts can be replaced.
Wear sleeves have been devised to help protect the front of support block and to provide easily replaceable wear components in comparison to the entire block. It is known to equip a cutting tool assembly with a spray nozzle for spraying fluid onto a cutting tool so as to cool the tool thereby lengthening tool life. It is also known that free rotation of a cutting bit within the support block of the cutting tool promotes tool life by promoting even wear of the cutting bit. Current cutting tool assemblies often affix a shank of the cutting bit within a bore or a wear sleeve of the support block or within the a bore of the support block so the bit can rotate within a bore. It is a common occurrence for the cutting bits to seize within the bore preventing free rotation of the cutting bit and causing premature failure of the cutting bit.
The present invention has been developed in view of the foregoing.
The present invention provides a cutting tool assembly including a support block, wear sleeve and cutting but which lubricates an interface of the cutting bit and the wear sleeve to promote even wear of the cutting bit thereby deterring premature failure of the cutting bit. A seal between the support block and the wear sleeve allows the fluid to pass from a passage in the support block to a passage in the wear sleeve. The wear sleeve passage discharges into a bore of the wear sleeve which holds a shank of the cutting bit. The fluid lubricates the space between the shank of the cutting bit and the bore of the wear sleeve. The lubrication promotes free rotation of the shank of the cutting bit within the bore of the wear sleeve.
An aspect of the present invention provides a cutting tool assembly for use in mining or road milling, comprising a support block having a bore and a fluid passage; a wear sleeve having a shank structured to fit at least partially within the bore of the support block, a collar, a bore for receiving a cutting bit and a fluid conduit, the fluid conduit extending from the collar to bore of the wear sleeve; and a seal located between collar of the wear sleeve and the support block, wherein the seal has at least one channel capable of delivering fluid from the fluid passage of the support block to the fluid conduit of the wear sleeve.
Another aspect of the present invention provides a method of lubricating a cutting tool assembly for use in mining and road milling comprising the steps of providing a cutting tool assembly with a support block, wear sleeve and cutting bit having a shank inserted into the wear sleeve and injecting a fluid between the wear sleeve and the shank of the cutting bit to lubricate the shank and permit the cutting bit to rotate.
Yet another aspect of the present invention provides a method of lubricating a cutting bit for use in mining and road milling comprising the steps of providing a cutting tool assembly having a support block with a fluid passage, a wear sleeve inserted into the support block having a bore and a fluid conduit having a discharge end in the bore, a seal between a shoulder of the wear sleeve and the support block, the seal having at least one opening to allow fluid to pass from the fluid passage of the support block to the fluid conduit of the wear sleeve, and a cutting bit having a shank inserted into the wear sleeve; providing fluid to the support block whereby the fluid is conveyed through the fluid passage of the support block, through at least one opening of the seal, through the fluid conduit of the wear sleeve and into the area between the shank of the cutting bit and the bore of the wear sleeve.
These and other aspects will become more apparent from the following description.
For purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. In this application, the use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, in this application, the use of “or” means “and/or” unless specifically stated otherwise, even though “and/or” may be explicitly used in certain instances.
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The fluid passage 80 of the pedestal 100 is in fluid communication with a distribution channel 90 of the seal 60. A series of openings 136 about the distribution channel 90 of the seal 60 allow fluid to pass to one or more fluid conduits 34 in the wear sleeve 30. The fluid conduit 34 extends from the seal 60 to the annular ring 38 of the wear sleeve 30. At this point, fluid can pass around the annular slot 38 of the wear sleeve 30 and recess 44 of the cutting bit 40, around the spring clip 46 and between the shank 42 of the cutting bit 40 and bore 31 of the wear sleeve 30 before exiting through the front or rear of the bore 31 of the wear sleeve 30. The fluid flow lubricates the area between the shank 42 and the bore 31 and helps to keep it free from dust and debris. This helps to keep cutting bit 40 rotating. Rotation of the cutting bit 40 promotes even wear and reduces the likelihood of premature bit failure.
A more detailed view of the seal 60 is shown in
In certain respects, the seal 60 is made from polyurethane, nitrile rubber, fluoroelastomer, ethylene propylene, natural rubber, silicone rubber, poly(tetrafluoroethene) (PTFE), polyoxymethylene and like material. In other respects, the seal is a metallic material. Although the seal 60 is shown, as an annular ring coaxially located about the shank of the wear sleeve, it is contemplated that the seal may be any suitable configuration for delivering fluid from the support block to the wear sleeve. For example, instead of extending around the shank of the wear sleeve, the seal may be entirely located adjacent shank of the wear sleeve and the fluid passage of the support block and the fluid conduit of the wear sleeve.
Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims.
