BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B are perspective views of a prior art torsion bar attachment interface with respect to a cross-member of a frame of a motor vehicle.
FIG. 2 is a perspective, exploded view of a first embodiment of the torsion bar indexing attachment mechanism according to the present invention.
FIG. 3 is a perspective, operational view of the torsion bar indexing attachment mechanism of FIG. 2, shown operatively interfaced at a first index.
FIG. 3A is a perspective, operational view of the torsion bar indexing attachment mechanism as in FIG. 3, shown operatively interfaced at a second index.
FIG. 4 is a perspective, operational view of the torsion bar indexing attachment mechanism of FIG. 2, shown operatively interfaced with respect to a cross-member.
FIG. 5 is a perspective, exploded view of a second embodiment of the torsion bar indexing attachment mechanism according to the present invention.
FIG. 6 is a perspective, operational view of the torsion bar indexing attachment mechanism of FIG. 5, shown operatively interfaced with respect to a cross-member.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the Drawing, FIGS. 2 through 6 depict examples of a torsion bar indexing attachment mechanism according to the present invention for attaching a range of different torsion bars to an adjustment arm which is, in turn according to a preferred example of operation which involves a motor vehicle torsion bar suspension, adjustably interfaced with a cross-member of a frame of a motor vehicle, wherein FIGS. 2 through 4 depict a first embodiment of the torsion bar indexing attachment mechanism 100, and FIGS. 5 and 6 depict a second embodiment of the torsion bar indexing attachment mechanism 100′. The motor vehicle torsion bar suspension may utilize the present invention with respect to either, or both, the front and rear set of wheels.
Turning attention to the first embodiment of the torsion bar indexing mechanism 100, FIGS. 2 and 4 depict a conventional cross-member 102 which is generally structurally similar to that described with respect to FIG. 1A. The cross-member 102 has a U-shape, defined by first and second sidewalls 102a, 102b which are both integrally connected, in normal relation, to an upper wall 102c. At each of the left and right end portions 102L, 102R, the first and second sidewalls 102a, 102b are: a non-circular adjuster nut hole 104; an aperture 106 in at least one of the first and second sidewalls (see FIG. 4); and the inner surface of the upper wall is provided with a concave surface contour 108 (see FIG. 2) which is disposed concentrically with respect to the aperture 106.
The end 110a of each torsion bar 110 of a range of torsion bars has a polygonal-faced head 112, a hexagon being shown by way of preferred example, and is the same as that used in the prior art as described with respect to FIGS. 1A and 1B. The torsion bar head 112 is received into a counterpart polygonal-faced head seat 114 (a hexagon being shown to compliment the hexagon-faced torsion bar head 112) of an adjuster barrel 116. The adjuster barrel 116 has at least one barrel tab 118 upstanding on its annular outer barrel surface 116a and preferably has an end flange 116b for providing seating guidance. Preferably, the outer barrel surface 116a is cylindrical and the end flange 116b is annular.
Each adjuster arm 120, there being an adjuster arm for each of the left and right end portions of the cross-member 102, has a barrel receptacle 122 formed therein for indexingly receiving thereinside the adjuster barrel 116, wherein a receptacle surface 122a is configured and sized to snugly abut the outer barrel surface 116a, preferably also cylindrical. The adjuster barrel 116 is indexingly disposed with respect to the adjuster arm by the barrel tab being received by a selected receptacle notch 124 formed in the receptacle surface 122a of the barrel seat 122, wherein n possible positions of the barrel receptacle are provided, each defined by a respective barrel notch, and each corresponding to use with a selected torsion bar.
With regard to indexing, a selected notch 124 is defined as a baseline angular datum. With respect to the datum, the angular separation, θ, of notches are governed by the following equation, for i=1 to n−1:
θ=(360/n)i+(α)i.
where theta, θ, is the position of the baseline notch (i.e., zero degrees), n is the number of indexable positions, and alpha, α, is a desired incremental angle (i.e., two degrees).
The result is the ability to align the barrel tab 118 with an appropriate receptacle notch 124, as is appropriate for a selected torsion bar of the range of torsion bars, of the n discrete angular positions. All values of n and α are contemplated by the present invention. For the construction shown in FIGS. 2 through 3B, n=6 and α=2 degrees.
By way of example, FIG. 3 shows a torsion bar head 1121 of a first torsion bar 1101 received in the head seat 114, wherein in proper installation with respect to the adjuster arm 120 a first receptacle notch 124, receives the barrel tab 118 of the adjuster barrel 116. Now, in the event the installation involved a second torsion bar 1102 different from the first torsion bar 1101, then with its head 1122 seated in the head seat 114, a second receptacle notch 1242 would receive the barrel tab 118, as illustrated at FIG. 3A.
An adjuster mechanism 125 is provided for adjusting the angular orientation of each adjuster arm, separately, with respect to the cross-member, is preferably similar to that of the prior art and described above with respect to FIG. 1B. The adjuster arm 120 has an arm member 120a and a convex contour surface 120b concentrically disposed with respect to the barrel receptacle 122. The arm member 120a has a land 120c adapted to abut the end 130a of an adjuster bolt 130. The adjuster bolt 130 is threadably engaged with a laterally elongated adjuster nut 132 which is seated in the adjuster nut hole 104.
In operation, the torsion bar head 112 is seated into the head seat 114 of the adjuster barrel 116, and the adjuster barrel, in turn, is seatably received into the barrel receptacle 122, wherein the barrel tab 118 is indexed to the particular, predetermined receptacle notch 124 which is appropriate for the selected torsion bar of the range of torsion bars. The torsion bar is then torsionally preloaded for the suspension system and particular torsion bar, and then adjusted to an appropriate torsional load by the adjuster mechanism 125, wherein the adjuster bolt is selectively rotated so that it threads with respect to the adjuster nut and thereby adjusts the angle of the adjuster arm 120 relative to the cross-member 102.
The loads applied upon the adjuster barrel 116 by torsional loads on the torsion bar 110 will cause the adjuster barrel to tend to rotate around the axis of the torsion bar. The barrel tab 118 of the adjuster barrel reacts against the receptacle notch 124 into which it is seated so as to thereby resist this tendency to rotate.
While compressive loading of an adjuster bolt is preferred, operation is not limited to this type of loading, as the torsion bolt can be rearranged with respect to the adjuster arm so as to be in extension, as opposed to compression.
As an optional construction for the adjuster barrel 116, the adjuster barrel may be provided with an axial slit 116c (see FIG. 2), wherein torsional loads of the torsion bar will cause the adjuster barrel to expand and thereby cause the outer barrel surface 116a apply a pressure to the receptacle surface 122a.
Turning attention now to FIGS. 5 and 6, a second embodiment of the torsion bar indexing attachment modality 100′ is depicted, wherein like parts to those described with respect to the first embodiment of the torsion bar indexing attachment mechanism 100 are identified by like numbers, and modified like parts are identified by like numbers with a prime, wherein the structural and operational aspects may be understood from the hereinabove description with respect to FIGS. 2 through 4.
Now the cross-member 102′ is modified so that each of the first and second sidewalls 102a′, 102b′ are provided with a bushing 150 at each of the left and right portions of the cross-member. The adjuster barrel 116′ is now provided at each end with a barrel arbor 152a, 152b. It will be understood from FIG. 6 that when assembled in the general sense of the description with respect to the first embodiment 100, the major difference is that the arbors 150a, 150b rotatably rest on the bushings 150, and there is an absence, or at least no need for, the concave contour surface of the cross-member abutting a convex contour surface of the adjuster arm, as was utilized in the first embodiment 100. Otherwise, operation of the first and second embodiments is essentially the same.
To those skilled in the art to which this invention appertains, the above-described preferred embodiment may be subject to change or modification. Such change or modification can be carried out without departing from the scope of the invention, which is intended to be limited only by the scope of the appended claims.
Patent Application
20080048371
