Pick Tool with a Removable Shank
Pick tool assemblies for use with formation degradation machines, such as road milling, mining, trenching or drilling machines, may be disposed on rotatable drums, wheels, continuous chains, drill bits or the like and brought into engagement with such formations as rock, asphalt, coal or concrete to break up or otherwise degrade the formations. Such pick tool assemblies may comprise a shank comprising a forward end and a rearward end wherein the rearward end may be formed for retention in a bore of a block attached to a driving mechanism and the forward end may comprise a body detachably and nonrotatably fastened thereto. Further, an impact tip may be bonded opposite the rearward end.
This application claims priority to U.S. Provisional Pat. App. No. 61/678,384 filed on Aug. 1, 2012, which is incorporated herein by reference for all that it contains.
BACKGROUND OF THE INVENTIONThe present invention relates generally to formation degradation machines such as the type used in road milling, mining, trenching or drilling. More specifically, the present invention relates to pick tools used by formation degradation machines for engaging and degrading a formation. Pick tools may be disposed on rotatable drums, wheels, continuous chains, or drill bits and brought into engagement with such formations as rock, asphalt, coal or concrete to break up or otherwise degrade the formations.
While degrading a formation, pick tools may be subjected to severe abrasion and thermal wear. However, different portions of pick tools may wear at different rates. For example, exposed portions of a pick tool may experience rapid wear while shielded portions may experience little to no wear. Thus, it may be desirable to replace those portions experiencing the most wear relatively frequently while retaining those portions in place that receive less wear.
An example of a pick tool is found in U.S. Patent No. 7,401,863 to Hall et al., herein incorporated for all that it contains, which discloses a pick comprising a shank attached to a base of a steel body, a cemented metal carbide core press fit into the steel body opposite the shank, and an impact tip bonded to a first end of the core opposite the shank. In this example, wear on any portion of the pick tool may require replacement of the entire tool, thus wasting unworn material.
Another example of a pick tool is found in U.S. Pat. No. 4,804,231 to Buljan et al., herein incorporated for all that it contains, which discloses a cutter bit holder that has a replaceable cutter tip which can be replaced in the field when the cutter tip is worn by unscrewing a flange from the shank of the holder and replacing the worn cutter tip with a new one. However, Buljan et al. relies on a threaded connection that may undesirably rotate during use.
Thus, while known pick tools may have proven acceptable for their intended applications, there remains a need for improvement in the pertinent art.
BRIEF SUMMARY OF THE INVENTIONA pick tool assembly may comprise a shank comprising a forward end and a rearward end wherein the rearward end may be formed for retention in a bore of a block attached to a driving mechanism and the forward end may comprise a body detachably and nonrotatably fastened thereto. Further, an impact tip may be bonded opposite the rearward end.
In some embodiments of the pick tool assembly, the impact tip may be bonded to the forward end. In such embodiments, the forward end may be disposed within a cavity passing completely through the body.
In other embodiments, the impact tip may be bonded to the body such as by being brazed in a recess of the body or some other means known in the art. In such embodiments, the forward end may be disposed within a socket within the body. To aid in transferring forces between the body and the shank, the body may comprise a radial flange disposed adjacent the socket that may interact with an outer shelf disposed around an exterior of the forward end.
The forward end may be press fit within the socket of the body. To aid in the press fit, the forward end in various embodiments may be hollow, slotted, tapered or combinations thereof. In some embodiments, the forward end may comprise a compliant ring disposed thereon or a pin insert to aid in retention within the socket.
The driving mechanism may comprise a drum, wheel, chain, or bit with a block attached thereto. The shank of the pick tool assembly may be nonrotatably retained in the bore of the block. Also, the body may comprise at least one detachment groove disposed adjacent the forward end to aid in detaching the body from the forward end and the forward end may comprise at least one detachment groove disposed to aid in detaching the shank from the block.
Referring now to the figures,
The body 306 and impact tip 307 may be the most quickly worn parts in the pick tool assembly 301. Having a shank 302 that is detachably fastened to the body 306 may be beneficial because it may allow for the timely replacement of the body 306 and impact tip 307. The shank 302 of the pick tool assembly 301 may last longer than the body 306 and the impact tip 307 because the shank 302 may be disposed in the bore of a block and shielded by the body 306. The shank 302 may still be functional when the body 306 and impact tip 307 have lost their usefulness. By making the shank 302 removable, the overall tool life of the pick tool assembly 301 may be increased because the shank 302 may be reused several times while the body 306 and the impact tip 307 are detached and replaced. Additionally, the proposed invention may be beneficial because the body 306 may undergo different treatments or other finishing operations than the shank 302. This may allow for more specialized customization of the properties of the shank 302 and the body 306 and improved performance and wear resistance overall. For example, the shank 302 may be made from inexpensive steel while the body 306 may be made from stronger, heat-treated steel. The body 306 may also be hard-faced with more wear-resistant materials to improve its life.
The body 306 may further comprise one or more detachment grooves 314 disposed on a flange of the trailing end 305 of the body 302. The detachment grooves 314 may aid in removal of the body 306 from the shank 302 by allowing a pick removal tool to be inserted between the body 306 and a block.
The rearward end 305 of the body 306 may comprise a socket 316 in which the forward end 303 of the shank 302 may be disposed. The forward end 303 may be press fit within the socket 316. The forward end 303 may also comprise various features that may aid in the press fit. In the embodiment shown, the forward end 303 comprises a slot 317 that may aid in the press fit by causing it to be more pliant. The forward end 303 may also comprise a slight taper as shown to aid in the press fit.
A detachment groove 424 may be disposed on the outer shelf 418. The detachment groove 424 may aid in removal of the shank 402 from a block by allowing a pick removal tool to be inserted between the outer shelf 418 and the block.
Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.
Claims
1. A pick tool assembly, comprising:
- a shank comprising a forward end and a rearward end;
- the rearward end formed for retention in a bore of a block attached to a driving mechanism;
- the forward end comprising a body detachably and nonrotatably fastened thereto; and
- an impact tip bonded opposite the rearward end.
2. The pick tool assembly of claim 1, wherein the impact tip is bonded to the forward end.
3. The pick tool assembly of claim 2, wherein the forward end is disposed within a cavity passing completely through the body.
4. The pick tool assembly of claim 1, wherein the impact tip is bonded to the body.
5. The pick tool assembly of claim 4, wherein the forward end is disposed within a socket of the body.
6. The pick tool assembly of claim 5, wherein the body comprises a radial flange disposed adjacent the socket that transfers forces to an outer shelf disposed around an exterior of the forward end.
7. The pick tool assembly of claim 5, wherein the forward end is press fit within the socket of the body.
8. The pick tool assembly of claim 7, wherein the forward end is hollow to aid in the press fit.
9. The pick tool assembly of claim 7, wherein the forward end is slotted to aid in the press fit.
10. The pick tool assembly of claim 7, wherein the forward end is tapered to aid in the press fit.
11. The pick tool assembly of claim 5, wherein the forward end comprises a compliant ring disposed thereon to aid in retention within the socket.
12. The pick tool assembly of claim 5, wherein the forward end comprises a pin insert to aid in retention within the socket.
13. The pick tool assembly of claim 1, wherein the impact tip is brazed to the body.
14. The pick tool assembly of claim 1, wherein the shank is nonrotatably retained in the bore of the block.
15. The pick tool assembly of claim 1, wherein the driving mechanism comprises a drum, wheel, chain, or bit.
16. The pick tool assembly of claim 1, wherein the impact tip is disposed within a recess of the body.
17. The pick tool assembly of claim 1, wherein the body comprises at least one detachment groove disposed adjacent the forward end.
18. The pick tool assembly of claim 1, wherein the forward end comprises at least one detachment groove disposed adjacent the block.
Type: Application
Filed: Jul 31, 2013
Publication Date: Feb 5, 2015
Inventors: David R. Hall (Provo, UT), Francis E. Leany (Salem, UT), David C. Wahlquist (Spanish Fork, UT), Braeden Brown (Provo, UT), Benjamin J. Spence (Riverton, UT)
Application Number: 13/955,094
International Classification: E21C 35/18 (20060101);