WO1993025401A1

WO1993025401A1 - Rigid beam suspension assembly for trailers

Info

Publication number: WO1993025401A1
Application number: PCT/CA1993/000251
Authority: WO
Inventors: Real O. Mercier
Original assignee: Mercier Real O
Priority date: 1992-06-17
Filing date: 1993-06-16
Publication date: 1993-12-23
Also published as: MX9303603A; AU4304493A; CA2090068A1

Abstract

A rigid beam suspension assembly for trailers is provided having a transverse pivot shaft rigidly affixed to a frame of the trailer and projecting horizontally outwardly therefrom; a cylindrical bearing rotatably mounted on the pivot shaft; a rigid beam member rigidly affixed at a forward end thereof to the cylindrical bearing at its outer end and perpendicular thereto, and adapted at a mid portion to support a wheel axle; and the rigid beam member having a compression spring means affixed at a rear end thereof to meet the vertical frame.

Description

RIGID BEAM SUSPENSION ASSEMBLY FOR TRAILERS

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to tractor-trailer rigs in general, and in particular to semi-trailers and the like such as over-the-road haulers, liquid tank - trailers, and so forth. More particularly still, it relates to wheel suspensions of the rigid beam type.

Prior Art of the Invention

Rigid beam suspensions are known from United States Patent 3,332,701 granted July 25, 1967, to Lloyd D. C Masser and titled "Suspension For Automotive Vehicles." The patent states that the suspension disclosed is especially adapted for the use of air springs in commercial vehicles, and continues:

"The inherent lack of lateral stability of an air spring, which essentially is an air-inflated bag, has necessitated in previous air suspensions the use of relatively complicated systems of torque rods, lateral stabilizer bars, bolsters, and the like, especially in tandem structures. Such equipment is relatively heavy and reduces the amount of payload which can be carried by the vehicle where load restrictions are in force. Moreover, such equipment is expensive and gives rise to design problems in the relatively crowded understructures of commercial vehicles.

The object of this invention is to provide a simple, light-weight, relatively inexpensive air spring suspension structure which eliminates the i π necessity for torque rods, stabilizer bars, bolsters, and the like and which can be used in either single- or multiple-axle arrangements.

In general, the invention contemplates the use of substantially rigid control arms extending

1 c longitudinally away from pivotal mounts at opposite sides of the vehicle, the springs being disposed in load-transmitting relation between portions of the arms and vehicle frame.

A substantially rigid whe e 1 -c arrying axle is

20 attached to the arms, and each axle attachment includes two pins which extend generally parallel to the axle, the pins being spaced apart to provide a broad base for support against lateral thrust on the control arms and against drive or braking torque on the axle. Bodies of rubber or the like are confined between the pins and adjacent portions of the axle attachments. The arms and their pivotal mounts and the axle and axle attachments are capable of themselves of withstanding the torsional and lateral forces thereon incidental to

1^ operation of the vehicle."

A generally useful background discussion of rigid beam type suspensions is found in United States Patent 4,566,719 granted January 28, 1986 to Ervin K. Van Denberg. The patent states:

J-5 "Rigid beams, while denoted 'rigid' , do, of course, flex during operation of the vehicle. This flexing is , simply stated , less than that of a conventional, flexible leaf spring type of beam; thus requiring resilient mountings at either or

?- both of the two aforementioned points. Not only do such beams flex during operation, but they must be allowed to flex or, given reasonable sizes and thicknesses, they will break during vehicle operation. Indeed, early attempts to rigidity connections in the beams either at the frame 5 connecting member (e.g. a hanger bracket) or at the axle connection (or at both) without providing sufficient resiliency at one or both of the connections proved futile in that frequent beam breakage was experienced."

1" The patent continues to state that one early solution to this problem was to provide a relatively small resilient pivot bushing at the hanger (connection) and that while somewhat successful, wear-out of the resilient bushing was a frequent problem.

i r. Both United States Patents 3,332,701 and 4,566,719 are incorporated herein by reference.

SUMMARY OF THE INVENTION

The present invention provides a rigid beam suspension system exhibiting improved torsional stability while being simple in design and construction. In a narrower aspect, the present invention provides a combined main frame and suspension assembly, which, in certain embodiments permits a decrease in trailer height and/or lower center of gravity for improved stability.

In a preferred embodiment of the present invention, the conventional I-beams, running the length of the trailer, are replaced by a tubular beam, such as a rectangular tube, which provides additional capacity for carrying fuel or other liquids.

It is expected that the present invention will lead to the design of multi-wheel vehicles, especially semi¬ trailers, which exhibit improved stability and safety of operation. It appears that such vehicles may provide better load weight distribution among the wheels, and should improve the durability of the unit in road use. In the embodiments incorporating a closed or open tubular longitudinal beam additional load may be accomodated, leading to larger loads for light materials, or lower center of gravity for heavy materials such as liquids, or additional fuel capacity. Accordingly, the present invention provides a rigid beam type wheel suspension for a wheeled vehicle, comprising, on each side of said vehicle: a transverse pivot shaft rigidly affixed to a frame of said wheeled vehicle and projecting horizontally outwardly therefrom; a cylindrical bearing rotatably mounted on said pivot shaft; a rigid beam member rigidly affixed at a forward end thereof to said cylindrical bearing at its outer end and perpendicular thereto, and adapted at a mid portion to support a wheel axle; and said rigid beam member having a compression spring means affixed at a rear end thereof to meet said vertical frame.

In one aspect, the present invention provides a combined main frame and suspension assembly for trailer vehicles and the like, comprising: a main load carrying frame for said trailer vehicle, a longitudinal tubular main frame beam extending substantially along the length of said main frame at a lower part thereof and adapted for storage of cargo therein; and at least a pair of wheel suspension assemblies affixed one on either side of said tubular main beam. In a further embodiment, the invention provides a combination of a main frame with suspension assemblies for a trailer vehicle, or the like, comprising: a main load carrying frame for a trailer body or load, having a main tubular beam longitudinally extending along said main frame providing the vehicle with torsional stability and with tank capacity for carrying fuel or other cargo, said main frame further having a number of pairs of cross beams spaced along the length of said tube beam, extending from both sides of said tube beam at its upper portion and forming a base for positioning the trailer body or loads, a number of pairs of suspension assemblies corresponding to a number of said cross beams, each pair of said suspension assemblies linking a pair of split-wheel axles to the two sides of said tube beam respectively, each suspension assembly further comprising on each side of said tube beam a cushioning pneumatic spring, a wheel axis support arm which extends parallel to said tube beam and is pivoted at its one end on a shaft extending transversely through said tube beam at its lower portion, and attached at its other end to the spring which is secured to said tube beam, said shaft being held at its outer end by a bracket depending from said cross beam, said wheel axles being incorporated into said support arm at its middle portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiment of the present invention will now be described in detail in conjunction with the attached drawing figures, in which:

Figure 1 is a side elevation of a wheel suspension and partial view of the frame of a trailer in accordance ι π with the present invention;

Figure 2 is a view along the line A-A in Figure 1; and

Figure 3 is a top partially exploded view of the right-hand suspension shown in Figure 2 without the 5 trailer frame. Figures 4, 5, and 6 show additional embodiments of the tubular longitudinal beam, and of the loading portion of the vehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to Figures 1 and 2 of the drawings there is illustrated part of a trailer showing one set of two dual wheels on either side, usually being one of several sets of such wheels supporting the trailer on the road surface along the length thereof. The trailer frame comprises a supporting rectangular tubular beam 10 running along the length of the trailer, which is shown here only in the vicinity of a set of trailer wheels 11.

An axle 12 of the wheels 11 is anchored in a suitable

^*"- and conventional manner on a rigid beam 13 having at one end thereof a conventional air bag spring 14 and welded at its other end to a swivelling pivot bearing (fulcrum) 15, the bearing 15 surrounding and mounted on a fixed shaft 16 with a cylindrical TEFLON ( TM) bushing 17 between the swivelling bearing 15 and the fixed shaft 16. The shaft 16 extends on either side of the rectangular beam 10, piercing through and being welded to the latter. Between the outer wall of the rectangular beam 10 and the adjacent end of the bearing 15 there is a washer 18 welded to the outer wall of the rectangular beam 10 in order to protect it from wear and friction due to the movement of the cylindrical bearing 15. The outside end of the cylinder 15 is prevented from axial movement by means of a bolt 19 bolted to a bracket 20 at the end of which the shaft 16 is anchored. The upper end of the bracket 20 is affixed to cross beam 21, which, together with the rectangular beam 10 to which it is welded, forms part of the supporting frame of the trailer. Cross beam 21 also terminates at its outer end in a vertical stake well 22 for receiving a stake 23 which forms part of the frame superstructure of the trailer. A trailer load is shown symbolically as tree logs 24.

In the above description only the right-hand side suspension was described, the other (left-hand) side being a mirror image thereof. As may be seen from the description the simple construction of the rigid beam suspension exhibits a pivot joint with a long interface between the pivoting cylindical bearing 15 and the fixed pivot shaft 19, thereby improving the stability of the independent wheel suspension. A shaft 16 thickness of three inches in diameter is sufficient for an eight foot long shaft spanning the width of a conventional heavy duty hauler.

In the disclosed embodiment, the shaft 16 extends transversely through the main support beam 10 at a level 9.5 inches above its bottom wall, which is itself approximately 12 inches above ground in operation. In cross section the main support beam 10 is 24 inches by 30 inches and is made of 3/8 inch thick steel. The pivot cylindrical bearing 15 is made from steel tubing having 4 inches internal diameter and is 35 inches long. Thus the nylon bushing 17 is made from a 1 inch thick nylon tube having a 3 inches internal diameter and is also 35 inches long. The washer 18 is a 1/2 inch thick steel washer with 4 inches internal diameter.

As may be seen from Figure 2, the fact that the shaft 16 goes through the main support beam 10, permits smaller trailer height with the load being closer to the ground and therefore increased stability due to the lower center of gravity of the entire trailer. This would be particularly advantageous for liquid tank trailers, especially when they are not completely filled. Figure 5 shows a flat bed 25 trailer profile, in which some of the aforementioned advantages would still be obtained.

A further advantage of using a sealed rectangular or otherwise tubular box or cylindrical for the main frame beam 10 is that the enclosed volume may be used for additional fuel tank capacity, or for any other purpose. Of course, the advantages of the rigid beam suspension itself, as disclosed herein, are independent of whether the main support beam 10 is a volume enclosing tube or not. For it may be any other type of sufficiently rigid support beam for anchoring a fixed pivot shaft on either side thereof.

The rigid beam 13 itself is square in cross section measuring 6 inches on each side with the axle 12 anchored through it at a distance of 27 inches from the center of the shaft 16. The central axis of the air bag 14, which is preferably bolted to a plate welded to the rigid beam 13, is at a distance of 23 inches from the center of the axle 12.

Figures 4 and 6 show such rigid beams 10 which are at least partly open at the top to communicate with the main volume containing enclosures 26 (Figure 4) and 27 (Figure 6), and so are adapted to increase directly the load capacity of the trailer, even for solid or granular loads; but more importantly for tank trailers, where given the same capacity the centre of gravity is lowered as in Figure 6.

Claims

WHAT IS CLAIMED IS:

1. A rigid beam type wheel suspension for a wheeled vehicle, comprising, on each side of said vehicle: a transverse pivot shaft rigidly affixed to a frame of said wheeled vehicle and projecting horizontally outwardly therefrom; a cylindrical bearing rotatably mounted on said pivot shaft; a rigid beam member rigidly affixed at a forward end thereof to said cylindrical bearing at its outer end and perpendicular thereto, and adapted at a mid portion to support a wheel axle; and said rigid beam member having a compression spring means affixed at a rear end thereof to meet said vertical frame.

2. A combined main frame and suspension assembly for trailer vehicles and the like, comprising: a main load carrying frame for said wheeled vehicles, a longitudinal tubular main frame beam extending substantially along the length of said main frame at a lower part thereof and adapted for storage of cargo therein; and at least a pair of wheel suspension assemblies affixed one on either side of said tubular main beam.

•*»•? ii ' 8 "i r SHEET

3. A combination of a main frame with suspension assemblies for a trailer vehicle, or the like, comprising: a main load carrying frame for a trailer body or load, having a main tubular beam longitudinally extending along said main frame providing the vehicle with torsional stability and with tank capacity for carrying fuel or other cargo, said main frame further having a number of pairs of cross beams spaced along the length of said tube beam, extending from both sides of said tube beam at its upper portion and forming a base for positioning the trailer body or loads, a number of pairs of suspension assemblies corresponding to a number of said cross beams, each pair of said suspension assemblies linking a pair of split-wheel axles to the two sides of said tube beam respectively, each suspension assembly further comprising on each side of said tube beam a cushioning pneumatic spring, a wheel axle support arm which extends parallel to said tube beam and is pivoted at its one end on a shaft extending transversely through said tube beam at its lower portion, and attached at its other end to the spring which is secured to said tube beam, said shaft being held at its outer end by a bracket depending from said cross beam, said wheel axles being incorporated into said support arm at its middle portion.

4. A combination as claimed in claim 3 wherein said shaft has a length of about the width of said trailer, each portion of said shaft which projects out of each side of said tube beam being essentially covered in its length by a low friction bushing which permits an outer pivot tube to slide thereover, permitting rotary movement to said support arm which is attached to said outer pivot tube.

5. A combination as claimed in claim 4 wherein a plate washer is provided on said elastic bushing between inner end of said outer pivot tube and the side of said tube beam for reducing friction.

6. A combination as claimed in claim 5 wherein said outer pivot tube at the outer end is held on said shaft and bushing by a cap together with said bracket depending from said cross beam.

7. A combination as claimed in claim 6 wherein said low friction bushing is made from nylon.

8. A combination as claimed in claim 7 in which said pneumatic spring is an air bag, which is installed between two air bag brackets one, of which is fixed to a side of said tube beam at its upper portion and the outer of which is secured at the rear extremity of said support arm thereon.