CA1215090A - Fastrack track assembly - Google Patents

Abstract

ABSTRACT OF DISCLOSURE

An improved track assembly for a track-type vehicle which includes a pair of parallel mounted track chain link assemblies engage able with the idler wheel of the vehicle and of sufficient width apart to straddle the road wheels of the vehicle so that the weight of said vehicle, borne by said road wheels, is directly borne by the inner surface(face) of the track pads, where said road wheels are of sufficient diameter to span the race of the track. When the vehicle traverses uneven or rough terrain, impact and torsional loads which cause premature wear or damage to the track assembly are minimized, thus prolonging the service life of the track assembly and the reduction of ground pressure from the track to minimize the damage to the environment from logging operations.

Description

aye r (a) TITLE OF INVENTION: FASTBACK TRACK ASSEMBLY
Inventor: John Parker ~,~
Residence: 1919 Thea Avenue NOW.
Gig Harbor, Washington 98335 Citizenship: U.S.A.

(b) RESERVED
(c) REFERENCES CITED
BACKGROUND OF THE INVENTION:
. _ _ 1. Field of Invention: This invention relates to an .
improved means of transferring the weight of a tracked vehicle to the track pads so as to minimize the pounds per square inch to be borne by the surface of the earth and so as to minimize 5 the wear Rand damage to the track from operation on rough and uneven terrain. In particular, this invention relates to a means of interfacing the road wheels to the track pads so that the weight of the vehicle is remove from the track chain while alignment of the track to the road wheels on rough or uneven 10 terrain is assured by the interlacing of the road wheel in the space between the parallel track chains both on the bottom and on the top of the track race.

2. Description of Prior Art_ It is known that vehicles, such as tractors and tanks, can be mounted on a pair 15 of endless track assemblies each including a plurality of track pads interconnected by means of a single-axis pivotal link assembly being comprised of a pin and bushing for each track.
The sprocket Ed drive wheel of the vehicle engages the pin and bushing assemblies to drive the track assembly with the track 20 assembly being guided by road wheels and an idler wheel ` I ' , ED;-:', lZ~;O9~CI

maintained in bearing contact with rail surfaces defined by the upper portions of each pair of links.
However, the existing means for transfer of -the vehicle weight to the tract pads includes the use of the track chain as 5 a bearing face for the road wheels which results in accelerated wear and damage to the pin and bushing assemblies which make up the track chain from torsion and impact loads resulting from operation of the vehicle on uneven and rough terrain. The component most susceptible to damage and wear in the tracked 10 vehicle is the pin and bushing assembly joining the track pads and making up the track chain. The applicant's invention relates specifically to a means by which to remove the direct load bearing function from the pin and bushing assemblies.
The applicant has commissioned a patent search for 15 conflicting and prior art through the firm of S~ILESINGER, ARK WRIGHT, HARVEY & DINS MORE and cites the following United States Patents as having been considered and found not conflicting for the reasons indicated. applicant has included herein what he believes to be the closest prior art of which he 20 is aware and this shall not be construed as a representation that no better art exists. Copies of the patents cited are included in the appendix per 37 CUR 1.98.
Patent No. Date Inventor Class 1,338,402 04/27/1920 GEE. Sibbett ' 305/47 The Sibbett patent discloses a tractor-tread link comprised of alternating single and double flanges and a connector pin to secure each successive link to the last. The Sibbett patent does not relate to a means for transferring the weight or tune vehicle to the track pads and therefore does not anticipate the 30 Parker invention.

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Patent No. Date Inventor Class 1,501,097 07/15/1924 ARM. Chase 305/56 The Chase patent relates to a traction belt having no hinged or jointed links or sections and having means for the drive wheels to contact the ground through the traction belt. The Chase patent does not relate to a means for transferring the weight of the vehicle to the track pad and therefore does not anticipate the Parker invention.
Patent No. Date Inventor Class . _ _ __ I 2,149,278 03/07/1939 JO Christmas 305/56 The Christmas patent relates to a pneumatic tire adapted to run on the track chain pins and bushings. The Christmas patent does not provide for direct interface of the road wheels to the track pads and therefore does not anticipate the Parker invention.
Patent No Date Inventor Class 2,350,445 06/06/1944 FOE. Burgess 305/56 The Burgess patent relates to a means of endless track construction utilizing pins and rubber bushings extending the width of the track upon which the road wheels directly interface. The Burgess patent does not provide direct interface of the road wheels to the track pads so as to protect the bushings and pins from direct loading and therefore does not anticipate the Parker invention.
Patent No. Date Inventor Class

3,829,013 04/01/1958 WIT. Patrick 305/47 I

.
The Patrick patent relates to a temporary crawler track ! mountable on existing designed rubber tired vehicles and as such does not anticipate the Parker invention.
Patent No. Date Inventor Class 3,163,249 12/29/1964 M. Ledohowski 305/57 The Ledohowski patent relates to another temporary endless tread for attachment to rubber tired vehicles being comprised of a pair of spaced rubber belts which are connected at spaced intervals by crossbars, having a convex bend so as to accommodate the rubber tires of the vehicle. The Leclohowski patent is not designed for use on rough and uneven terrain nor with sprocket-drive vehicles and therefore does not anticipate the Parker invention.

Patent No. Date Inventor Class _ _ _ _ 3.361,488 01/02/1968 JOY. Ohm 305/28 The Ohm patent is similar to the Ledohowski patent having the crossbars replaced by grouser rods. Again, conventional pneumatic rubber tired wheels are used, but the track is powered by a drive sprocket which meshes with the grouser rods. The Ohm patent does not provide a sturdy dual track chain nor a reduced pound per square inch footprint and therefore woes not anticipate the Parker invention.
Patent No. Nate Inventor Class 3,387,897 05/11/1968 KIWI. Reid 305/47 The Reid patent relates to a design of track shoe and means of putting them -together with a steel belted flexible rubber so -strip. The Reid patent is not durable when utilized on rough terrain as it does not utilize the track chain pin and bushing) heavy duty method of connection and does not provide for interface of the road wheels directly onto the track pads.
5 Therefore, it does not anticipate the Parker invention.
Patent No. Date Inventor Class 4r257l653 03/24/1981 TIC. Mazola, Jr. 305i28 The Mazola patent relates to a means of lessening the bearing load on the traditional track chain (pin and bushing) by lo using a twin track chain system and widened track roller. The Mazola patent still subjects the pin and bushing track chains to the vehicle load through the road wheels with the resulting damage to the pin and bushing assemblies from torsion and impact forces during operation on uneven and rough terrain. Therefore, 15 it does not anticipate the Parker invention.
In further effort to comply with 37 CRY 1.97, applicant cites the following commercially available tracked vehicles, having copies of their brochures included in the appendix, as non-conflicting prior art:

0 1. The Bombardier ~luskeg Skidder, produced by Bombardier Limited, Industrial Division, Valcourt, Quebec, Canada;
2. The Terraflex TF-140 Swamp Skidder produced by Bombardier, Inc. Inquisitorial Equipment Division, Valcourt, Quebec, Canada;
5 3. FMC Model 220 Multi-purpose Problem-Terrain Tractor;

4. FMC Model FOE Log Skidder FMC Corp., 200 E. Randolph Dr.
Chicago, ILL. 60601 The Skagit Corporation of Sidereal, Washington developed and field tested a low ground pressure, flexible steel track log skidder in 1968. The purpose of a low ground pressure skidder is to have a log skidder that could operate in soft, wet ground conditions with minimum soil and terrain damage.
Conventional crawler tractors and rubber tired skidders have ground pressures up to eighteen (18) pounds per square inch causing severe soil and terrain damage in soft and wet areas.
The low ground pressure track skidder has a ground pressure of

5.8 pounds per square inch evenly spread over the entire track due to each road wheel being independently supported by a torsion bar for movement. The Skagit prototype was called the lustier TT10, but was not marketed.
In 1974 the FMC Corporation developed and marketed an LOP
log skidder called the FMC 200 log skidder. Between 1974 and 1981, FMC produced and sold approximately 950 machines. The FMC
220 the current model) now features a 2000 hour guarantee on the steel with rubber pin bushing track. The replacement cost, however, us in the $25,000 to $28,000 range. The FMC 220 is still experiencing severe track problems even with the constant up-dating and testing.
applicant obtained the rights to the Hustler TT10 in 1972.
After refining the design through various prototypes, the key to 20 a reliable skidder having inexpensive maintenance was determined to be the track. The prototypes were named "Fastback Log Skidders" and the revolutionary track designed by applicant in 1983 was named the "Fastback". The final design was incorporated into the Fastback 170 in March, 1983 and has been 25 in continuous operation skidding logs in rough and uneven terrain without any significant Swiss of wear since said date.
The cost of a set of "Fastbacks" is under $8,000 and the service life is in excess of 2,500 hours of operation.

(d) OBJECTS END SYRIA OF TIRE INVENTION
1. Objects: It is therefore the primary object of the invention to provide an inexpensive track system having an , It extended service life when utilized on rough and uneven terrain in conjunction with tracked vehicles, which translates the weight of the vehicle directly to the track pads from the road wheels, while maintaining the strength of the track integrity by the use of dual track chains comprised of pin and bushing joined links.
2. Brief Summary: A track assembly for application to existing off-road tracked vehicles which is suitable to achieve the foregoing objectives, comprising a plurality of track pads, avowing a narrow plate protruding from and extending across the length of one face of the track pad, perpendicular to the race of the track, and having a slightly concave reverse face of the track pad so as to accommodate the chain links bolted thereto, a pair of parallel mounted track chain link assemblies, Whitehall the Doyle links of each track chain joined by a standard pin and bushing means, thus connecting the track pads together being pivotal in a single axis in the direction of the race of the track, and being capable of engaging the dual. sprocket drive wheel, the space between said track chains being of sufficient width to straddle the road wheels of the vehicle so that the weight of said vehicle borne by said road wheels is directly translated to the inner face of the track pads, and road wheels are of sufficient diameter to span the race of the track when stretched between the idler wheel and the sprocketctl drive Wylie. The road wheels surface which contacts the track pad can be made of a hard material such as steel or coated with a solid hard rubber sleeve.

(e) BRIEF DESCRIPTION OF THE Darlings Other objects of this invention will become apparent I from the following description and accompanying drawings wherein:
FIG. 1 Is an isometric view showing the concave face of ~15i~

an individual track pad.
FIG. 2 Is a side view of a single link of the track chain.
FIG. 3 Is a top view of the pin-bushing assembly.
FIG. 4 Is a view of the bottom of a track pad as installed on the two parallel track chains.
FIG. 5 Is a view of the sprocket Ed drive wheel engaged with the two parallel track chains.
FIG. 6 Is a view of a road wheel straddled by the two parallel track chains.
FIG. 7 Is a side view of the complete track assembly as installed.
(f) SPECIFICATION
1 Detailed Description and Best Mode of Cargo Out .

15 the Invention:
-inure 1 illustrates a rectangular track pad ~19) or grouser of rigid plate construction having a narrow plate (1) protruding from and extending across the length of the face of the track pad, perpendicular to the race of the track, located 20 approximately one-fifth of the width of the pad back from its leading edge Beyond the leading edge of the track pad extends a portion of said pad approximately one-half the length of the pad and centered on said leading edge, for a sufficient distance to overlap the rear edge of the next proceeding track pad. The plate of the track pad is formed in a flat "s" shape along its width, thus the rear edge of the track pad bends in the direction of the protrusion of the narrow plate and the lace opposite to said protrusion is slightly concave. At a point equal in distance from the 30pxotrusion of the narrow plate and the start of the bend in the rear edge of the track pad are two large clean-out holes in ..!

Sue the track pad, one on either end of the track pad and located so as to communicate into the space between the two links of the track chain, said clean out holes each being flanked by four holes of sufficient diameter to accommodate a standard bolt 5 and being so arranged so as to communicate with the two bolt holes drilled in the bottom fog of each link). The crescentlll) formed in the face of the tragic pad between the protrusion of the narrow plate and the rear edge (it) serve to protect the Hades) of the eight bolts which fasten the track 10 pad to the track chain Lennox).
Figure 2 illustrates the track chain link) with one fog having two bolt holes of sufficient diameter to accommodate a standard bolt. The aft end of thy link is equipped with a Hoyle) of sufficient diameter to encircle the bushing(l3?, while the fore end ox the link is equipped with a Hoyle) of sufficient diameter to securely mate with the pinwheel) which is -threaded through the bushingtl3), as is shown in Figure 3, thus enabling pairs of links to be joined together and with successive pairs into a continuous track chenille).
Figure 4 illustrates successive pyres) of Lennox) joined by the pun) and bushing) assemblies into two track Chinese) to which has been bolted a track puddle).
Figure 5 illustrates the drive Wylie) having sprockets) spaced around its circumference at both ends at 25 such intervals so as to engage the sprocket) into the spaces between the Lennox) and against the bushings(13) of both parallel track chains(l8), thus imparting movement of the track Chinese) and pads(l9) around the track race.
Figure 6 illustrates the load bearing road Wylie), 80 equipped with an optional hard rubber surfs, communicating the vehicle load to the lace of the track pads(l9) and the .
parallel track Chinese) straddling and guiding the continuous track system past the road Wylie).
Figure 7 illustrates the complete fastback assembly installed on a tracked vehicle having a sprocket Ed drive 5 Wylie) in the rear, an idler Wylie) in the front and four road Willis), communicating the vehicle load to the track pad surfaces between the parallel track Chinese) and spanning the race of the track thus maintaining the proper relationship of the track around the race. the tracked vehicle is equipped 10 with another identical fastback system on the side not shown.
(g) APPLICABILITY
The Fastback Track System is applicable to all types of tracked vehicles but is particularly useful in fogging operations on log skidders that must traverse fallen logs and 15 stumps on uneven and rough terrain. The low center of gravity and the straddling of the road Willis) by the parallel track Chinese) throughout the race of the track provided by the Fastback system removes the vertical and impact pressure from the parallel track Chinese) and the pin(14)-bushing(13) 20 assemblies, spreads the vehicle weight across the entire phase) of the track pod) and minimizes the torsional loads on the track Chinese) by putting them closer to the outer edges of the track pod).
Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims. Although the invention has been described with reference to preferred embodiments, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions and other changes not 30 specifically described may be made which will fall within the purview of the appended claims.

Claims (7)

I CLAIM:

1. An improved track assembly for a track-type vehicle of the type comprising a sprocketed drive wheel(20), an idler wheel(24), a plurality of longitudinally spaced road wheels(22), and an endless track assembly including a plurality of track pads(19) affixed by suitable means to and joined together by two parallel track chains composed of a plurality of track chain link(10) pairs, joined continuously one part to the next by standard pin(14) and bushing(13) means, the improvement comprising each of said idler(24) and road wheels(22) being solely engageable in loadbearing contact with the track pad surfaces(5) defined by the parallel track chains(18), said parallel track chains being of such distance apart so that the sprockets(21) at both ends of the drive wheel(20) communicate into the spaces between the track chain links(10) and against the bushings(13) continuously, while said road wheels(22) also engage the track pad surfaces(5) between the parallel track chains at the top of the track race.

2. The improved track assembly of Claim 1 wherein the track pad(19) is of rigid plate construction having a narrow (1) protruding from and extending across the length of the face of the track pad, perpendicular to the race of the track, located approximately one-fifth of the width of the track pad back from its leading edge(2), having an extension(3) beyond its leading edge across one-half the length of the pad and centered on said leading edge, for a sufficient distance to overlap the rear edge of the next preceding track pad.

3. The improved track assembly of Claim 2 wherein the plate of the track pad(19) is formed in a flat "s" shape along its width, so that the rear edge(4) of the track pad is bent in the direction of the protrusion of the narrow plate(1) and the opposite face(5) of the track pad(19) is slightly concave.

4. The improved track assembly of Claim 1 wherein the means of joining the track pad(19) to the track chain link is a standard bolt means with the head(12) fitting flush onto the face(11) of the track pad(19) and the shank of said bolt communicating through pre-drilled holes of suitable size in the track pad(19)(7) and on the leg(8)(9) of the track chain link(10), there being two of these bolt holes(8) on each track chain link(10) leg(9) and four sets of two each of these bolt holes(7) in the track pad(19) arranged so as to readily facilitate the communication of the bolt shank therethrough and secured by suitable nut means.

5. The improved track assembly of Claim 4 wherein the track pad(19) is provided with two large clean-out holes(6), one located near each end of the track pad, and of sufficient diameter and location to communicate to the space between the pair of track chain links(10) attached near each end of the track pad(19).

6. The improved track assembly of Claim 1 wherein the road wheels(22) are provided with a hard rubber coating on the circumferencial face(23) of the road wheel(22) which makes contact with the track pad(19) face(5).

7. The combination of the improved track assembly of Claim 1 with a track-type vehicle of a type comprising a drive wheel(20), having plurality of sprockets(21) continuously spaced around its circumference on each end of said drive wheel(20), and idler wheel (24) and a plurality of longitudinally spaced road wheels(22).