TRIANGULAR TRACK RESILIENT BOGIE SUSPENSION

• US 3,841,424 A
• Filed: 06/22/1973
• Issued: 10/15/1974
• Est. Priority Date: 12/27/1971
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Kenneth E. Wehr, Robert J. Purcell
• Inventors: Purcell, Robert J., Wehr, Kenneth E.
• Primary Examiner(s): Goodman, Philip
• Application Number:
  US05/372,829
• Time in Patent Office: 480 Days
• Field of Search: 180/9.5,9.62 305/25,22,29
• US Class Current: 180/9.5
• CPC Class Codes: B62D 55/08 Endless track units; Parts thereof
• CPC Class Codes: B62D 55/1086 Rubber springs
• CPC Class Codes: B62D 55/14 Arrangement, location, or adaptation of rollers

Abstract

An assembly for supporting and driving a vehicle with a crawler track has the track chain engaged on a pair of spaced apart idler wheels and a drive sprocket situated between the idlers and upwardly therefrom whereby the chain is maintained in a triangular configuration with the sprocket and drive elements situated well above the abrasive conditions at ground level, the entire assembly being oscillatable relative to the associated vehicle. To provide good resiliency and recoiling ability under high speed, heavy duty conditions each idler is mounted on one leg of an angled member which is pivoted to a fluid shock absorbing cylinder attached to an oscillatable track frame. Resilient means acting on the other leg comprises compression pads exhibiting a progressive spring rate whereby the idler may shift upwardly or backwardly as necessary to absorb shocks and reduce wear. Pairs of load carrying track rollers are mounted on bogies pivoted to the other leg of the angled member. In an alternate embodiment the track roller bogies are pivoted directly to the oscillatable track frame.

Claims

1. A vehicle supporting and driving assembly for a vehicle having an axle housing and a drive axle in the axle housing comprising:

a main pivot shaft securable to said axle housing, a track frame having an intermediate point secured to the main pivot shaft for pivotal oscillation of the track frame with respect to said axle housing, and having first and second ends extending from said intermediate point, idler support members at the first and second ends of the track frame, means pivotally and reciprocably securing the idler support members to the track frame ends, idlers rotatably mounted on the idler support members, cushion means responsive to reciprocation of the idler support members with respect to the track frame ends to cushion recoil of the idlers, a rotatable drive sprocket attachable to said axle housing and positioned between the ends of said track frame and above the idlers, means driving the rotatable drive sprocket by the drive axle, and a track chain emcompassing the idlers and drive sprocket and in driven engagement with the drive sprocket.

2. The combination of claim 1 wherein said idler support members comprise cranks having an intermediate point secured to the track frame ends and first and second legs diverging therefrom, said idlers being mounted on said first legs.

3. The combination of claim 2 further comprising, bogies pivotally mounted on the second legs of the cranks, and track rollers rotatably mounted on the bogies and engaging the track chain.

4. The combination of claim 1 further comprising, bogies pivotally mounted on the track frame, and track rollers rotatably mounted on the bogies.

5. The combination of claim 1 wherein said means pivotally and reciprocably securing the idler support members to the track frame ends comprises, cylinder means provided on the track frame ends, and, pistons slidable within the cylinder means, and wherein the idler support members are pivotally mounted on the pistons.

6. The combination of claim 5 wherein said cushion means comprises, second cylinders provided in the pistons, and pilot pistons disposed in the second cylinders, the pilot pistons and second cylinders defining gas chambers, and the cylinders, pistons and pilot pistons defining fluid chambers, whereby the gas chambers and fluid chambers may be filled with fluids to cushion recoil of the idlers and to maintain the track chain at any desired tension.

7. The combination of claim 5 wherein said cushion means comprises, an accumulator, stub shafts disposed in said cylinders, second cylinders formed in said pistons whereby the pistons are reciprocable within said cylinders and on said stub shafts, and conduit means communicating the cyliNders and the second cylinders formed in the pistons with the accumulator.

8. The combination of claim 1 wherein said means pivotally and slidably securing the idler support members to the track frame comprises, slides secured to the track frame, slide bearings slidable on the slides and pivotally mounting the idler support members, cylinder means secured to the track frame, piston means slidable within the cylinder means and in abutting engagement with the slide bearings, the cylinder means and piston means defining a fluid chamber, an accumulator, first and second parallel conduits communicating the fluid chamber with the accumulator, a relief bleed valve in the first conduit, and a check valve disposed in the second conduit, whereby upon restriction of the fluid chamber by movement of the piston means, the relief valve will open and fluid in the chamber will bleed into the accumulator, and upon subsequent expansion of the fluid chamber the check valve will open allowing fluid in the accumulator to return to the chamber.

9. The combination of claim 1 further comprising, housing means secured to the axle housing and extending upward therefrom, and wherein the drive sprocket is mounted on the housing means.

10. The combination of claim 1 further comprising resilient means responsive to pivoting of the cranks on the track frame.

11. The combination of claim 10 wherein the resilient means comprises spring means connecting the cranks and the main pivot shaft.

12. The combination of claim 10 wherein said resilient means comprises compression pads arranged for compression between the cranks and the track frame upon pivoting of the cranks.

13. The combination of claim 12 wherein said compression pads exhibit a progressive spring rate.

14. The combination of claim 13 wherein said compression pads comprise rubber blocks and wherein compression plates are provided on the track frame which progressively engage more and more of the block as it is moved toward the plates.