AU2001100065A4 - A supplementary spring assembly and connection means therefor - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: A supplementary spring assembly and connection means therefor The following statement is a full description of this invention, including the best method of performing it known to us: 2263342D1 .doc\hg BACKGROUND OF THE INVENTION THIS invention relates to a supplementary spring assembly and to connection means for connecting the supplementary spring assembly to an axle-mounted leaf spring assembly of a vehicle.

A number of different types of vehicle supplementary spring assemblies exist for supporting the leaf springs of vehicles. One such type of assembly is disclosed in South African patent 94/5738 in the name of the applicant. An elongate coil spring is provided which forms an axially extending passage. First and second threaded anchoring inserts or bungs are screwed into opposite ends of the passage. The anchoring inserts are provided with threaded axial bores into which the threaded shanks of first and second connector members are screwed.

The threaded shank of the first connector member is coupled to a hook which engages an eye defined by an uppermost leaf of the spring which has been scrolled around at one end of the leaf spring. The threaded shank of the second connector is in turn connected to the centre of an intermediate bracket from which a pair of axle hooks extend. The axle hooks are located around the axle of a vehicle to which the leaf spring of the vehicle is also mounted by means of Ubolts. This assembly finds application in cases where the axle is located above the leaf spring.

Where the axle is below the leaf spring, an axle angle bracket is used, with fitment of this angle bracket requiring the removal of the U-bolts to locate the angle bracket onto the centre bolt of the leaf spring.

In certain cases, an arrangement of the type disclosed in the applicant's South African patent 98/7959 may be used. However, installation of this arrangement may be problematic where brake pipes, brake cables or any other obstructions impede against the fitting of this type of assembly.

SUMMARY OF THE INVENTION According to a first aspect of the invention there is provided connection means for connecting a vehicle supplementary spring assembly to an axle-mounted leaf spring assembly, the leaf spring assembly being mounted to an axle of the vehicle by an axle mounting arrangement, with the supplementary spring assembly including an elongate coil spring, wherein the connection means connects a second end of the coil spring to a portion of the leaf spring assembly extending rearwardly of the axle mounting arrangement, with the connection point between the connection means and the second end of the coil spring overlying the axle mounting arrangement.

Preferably, the connection means comprises a pair of side plates including spanning means for joining the side plates in a rigid spaced apart relationship.

Typically, the spanning means include lower and upper spacer elements which extend between the side plates, with the lower spacer element being arranged to bear against an undersurface of the leaf spring assembly and the upper spacer element being located above the axle mounting arrangement so as to define the connection point.

In one version of the invention, the connection means includes an intermediate spacer element which is arranged to bear against an upper surface of the leaf spring assembly, wherein the intermediate spacer element and the lower spacer element define anchoring means for anchoring the connection means to the leaf spring assembly so that a predetermined clearance exists between the connection means and a rearmost portion of the axle mounting arrangement.

According to a second aspect of the invention there is provided a vehicle supplementary spring assembly for supplementing the spring force provided by a leaf spring assembly, with at least one end of the leaf spring assembly terminating in an eye arrangement, the leaf spring assembly being mounted to an axle of the vehicle by an axle mounting arrangement, the supplementary spring assembly comprising: an elongate coil spring; first connection means for connecting a first end of the coil spring to the eye arrangement of the leaf spring; and second connection means for connecting a second end of the coil spring to a portion of the leaf spring assembly extending rearwardly of the axle mounting arrangement, wherein the connection point between the second connection means and the second end of the coil spring overlies the axle mounting arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a side view of first connection means forming part of the vehicle supplementary spring assembly of the invention; Figure 2 shows a exploded top plan view of the first connection means of Figure 1; Figure 3 shows a side view of a first embodiment of a second connection means forming part of the vehicle supplementary spring assembly of the invention; Figure 4 shows an exploded top plan view of the second connection means of Figure 3; Figure 5 shows a side view of a second embodiment of second connection means forming part of the supplementary spring assembly of the invention; Figure 6 shows an exploded top plan view of the second connection means of Figure Figure 7 shows a side view of a third embodiment of second connection means forming part of the supplementary spring assembly of the invention; Figure 8 shows a top plan view of the second connection means of Figure 7; Figure 9 shows a perspective view of a fourth embodiment of second connection means forming part of the supplementary spring assembly of the invention; Figure 10 shows a side view of the second connection means of Figure 9; Figure 11 shows a side view of a fifth embodiment of second connection means forming part of the supplementary spring assembly of the invention; and Figure 12 shows a top plan view of the second connection means of Figure 11.

I -6- DESCRIPTION OF EMBODIMENTS Referring first to Figures 1 and 2, part of a main leaf spring 10 of a vehicle is shown terminating in a scrolled eye 12 through which a chassis pin 14 and bush 16 of a vehicle extends. First connection means in the form of an eyeconnection arrangement 18 comprises an underslung bracket hook 20 having a hook portion 22 which fits snugly around the scrolled portion 12 of the leaf spring from below. The opposite end of the bracket hook terminates at a first connection point 24 where a scrolled portion 26 of the bracket hook extends around a bush 28. A mounting bolt 30 passes through the bush, as well as through a pair of rectangular side plates 32 and 34 which are located on opposite sides of the leaf spring The sTde plates are spaced apart by the bush 28, an intermediate tubular spacer element 36 and a front draw bar 38, with the bolt 30 and a mounting bolt 40 in conjunction with lock nuts 42 serving to mount the side plates 32 and 34 firmly together. Both of the side plates are formed with front apertures 44 within which stub axles 46 extending from opposite ends of the draw bar locate. Apertures 50 and 52 are also formed in each of the side plates for locating the respective bolts 30 and 40. The draw bar is formed with a central aperture 54 through which the end of a threaded conrod 56 locates and is mounted by means of suitable nuts (not shown). The conrod 56 is in turn fitted to an internally threaded anchoring insert at one end of a coil spring assembly.

This coil spring assembly is well known, and is described in the applicant's corresponding South African patents nos. 94/5738 and 98/7959.

The entire eye connection arrangement 18 can easily be retrofitted to a vehicle without having to loosen or interfere with any existing mounting assemblies. In addition, tensile force on the conrod 56 in the direction of arrow 58 will serve to supplement the anchoring integrity of the eye connection arrangement by providing a locking effect arising from the resultant downward moment in the direction of arrow 60 and upward moment in the direction of arrow 62.

Referring now to Figures 3 and 4, a second connection means 70 is shown for connecting the opposite end of the coil spring rearwardly of a conventional axle mounting arrangement 72 including a pair of U-bolts 74 and a rubber block 76 around which the U-bolts extend. As is clear from Figure 4, the second connection means includes a pair of rectangular side plates 78 and each formed with five mounting apertures 82.1, 82.2, 82.3, 82.4 and 82.5. The side plates 78 and 80 are held rigidly together in a spaced apart relationship on opposite sides of the leaf spring 10 by means of front and rear mounting bolts 84 and 86, corresponding lock nuts 88, and tubular spacers 90 and 92.

The front bolt 84 passes through the hooked ends 94 of a pair of anchor rods 96, with washers 98 being interposed between the head of the bolt 84 and the nut The anchor rods are in turn fixed to an anchor rod bracket 100 via mounting nuts 102. The bracket 100 is formed with a central aperture for allowing it to be bolted to a threaded insert fitted into the opposite end of the coil spring. This arrangement is described in more detail in South African patent 98/7959, the contents of which are incorporated herein by reference.

As was the case with the first connecting arrangement illustrated in Figures 1 and 2, the second connecting arrangement of Figures 3 and 4 is fitted 'in situ.

In the example, the bolt 86 is passed through the pair of apertures 82.2 in the side plates, and the bolt 84 is passed through the pair of apertures 82.4.

When tensile stress is applied to the anchor rod in the direction of arrow 104, the tubular spacer 92 bears up against the undersurface of the leaf spring at contact point 106, and the front edges of the side plates bear against the Ubolts 74 at contact points 108. Apertures may be formed at any desired location along the side plates to accommodate different leaf spring configurations.

An advantage of the connecting arrangement of Figures 3 and 4 is that it can easily be retro-fitted, without interfering with the axle mounting arrangement.

In Figures 5 and 6, a second preferred embodiment of a second connecting arrangement 110 is shown. Those components which are similar or identical to the components illustrated in Figures 3 and 4 are identified with the same numerals. The second connection means 110 is configured so as to ensure that there is no interference whatsoever with the existing axle mounting arrangement 72 for mounting the leaf spring 10 to the axle, regardless of variations in thickness of the leaf spring pack 10. A pair of rectangular side plates 112 and 114 are each formed with three mounting apertures 116.1, 116.2 and 116.3. The arrangement for mounting the anchor rods in position is substantially identical to that illustrated in Figure 4, with the bolt 84 passing through the apertures 116.3, the intermediate spacer sleeve 90 and the nut 88.

The Idwermost mounting arrangement is also substantially identical, with the bolt 86 passing through the apertures 116.1 in the side plates 112 and 114, the intermediate spacer sleeve 92, and the nut 88.

An intermediate bolt 118 is passed through the intermediate apertures 116.2 and a nut 88. An intermediate spacer sleeve 120 may optionally be provided.

In the case of the leaf spring 10 having a pack height of, say, 30mm, then both the spacer sleeves 92 and 120 are omitted, with the upper surface of the shank of the bolt 86 bearing against the undersurface of the leaf spring 10, as is shown at 122. Similarly, the undersurface of the intermediate bolt 118 bears against the uppermost surface of the leaf spring 10, as is shown at 124. The spacing between the bolts 86 and 118 is such relative to the thickness of the leaf spring pack that the spaced apart plates 112 and 114 are locked in a forwardly angled position relative to the vertical of about 300, with a clearance of approximately 10mm existing between the rearmost portion of the axle mounting arrangement 72 and the side plates 112 and 114. It is apparent from Figure 5 that the anchor rods 96 are completely clear of and cannot potentially interfere with the axle mounting arrangement 72.

In the case of the pack height of the leaf spring pack 10 being, say, 24mm, as is indicated at 126, then the lowermost bolt 86 is fitted with a sleeve 92 to achieve the same angled locking effect of the side plates 112 and 114 by merely moving the point of contact 128 upwards whilst maintaining the forward angle of the side plates of approximately 300. For a still thinner leaf spring pack, the additional spacer sleeve 120 may be utilized. Varying thicknesses and numbers of spacer sleeves may thus be used rather than altering the positioning of the holes 116.1 and 116.2 to compensate for leaf spring packs of differing thicknesses.

A further advantage of the arrangement illustrated in Figures 5 and 6 is that the conventional axle mounting arrangement is not interfered with at all, both during mounting and during operation of the supplementary spring assembly of the invention.

In order to further ensure that the second connecting arrangement 110 does not interfere with the axle mounting arrangement 72, a pair of rectangular plates 129A and 129B are sandwiched between the side plates 112 and 114 and the axle mounting arrangement 72. The plates 129A and 129B are secured to leaf spring 10 by a pair of bolts 130 that extend on either side of the leaf spring.

Referring now to Figures 7 and 8, a still further embodiment of a connecting arrangement 131 is shown which is connected directly to the vehicle axle 132.

A pair of U-bolts 134 and 136 are fitted around the axle and serve as anchoring hooks. A lower bracket plate 138 is fitted to the free ends of each of the U-bolts, with the threaded free end 140 of each U-bolt passing through an aperture in the lower bracket plate 138 and being secured in position by means of a fastening nut 142. The opposite fixed ends of the U-bolts are bolted to an upper bracket plate 143 by means of fastening nuts 143A The lower bracket plate 138 bears against the leading edge 144 of a mounting block 146 used to mount and cushion the pack of leaf springs 148 relative to the axle 132. A pair of downwardly directed U-bolts 150 is used to mount the axle 132 and the leaf spring pack 148 firmly together. The upper bracket plate 143 is used to mount the supplementary coil spring 154 to the U-bolts 134 and 136 via a centrally located mounting bolt 156, which is in turn screwed into an anchoring insert 158 which is described in detail in South African patent 94/5738.

An advantage of the second mounting arrangement 131 is that the lower bracket plate 138 provides additional purchase in situations where a relatively strong supplementary coil spring 154 is being used. The lower mounting brack6t 138 prevents the U-bolts 134 from working loose, as would be the case with a bracketless hook which may tend to shake or spring loose when heavy loads are transported over uneven road surfaces.

Figures 9 and 10 show a fourth embodiment of a second connecting arrangement 160. The arrangement 160 comprises a slightly curved, rectangular base plate 162, with the curvature of the base plate 162 allowing the plate 162 to conform to the curvature of the leaf spring pack 164. A first end 166 of the plate 162 is secured to the leaf spring pack 164 by means of the axle mounting arrangement 72 described above. In particular, the first end of the plate 162 is bolted to the uppermost blade of the leaf spring pack 164.

A U-shaped housing 168 is bolted to a second end 170 of the plate 162.

Apertures are formed in the side plates of the housing 168 for receiving the stub axles of a draw bar 172 so as to allow the draw bar 172 to rotate around axis 173. The draw bar 172 is formed with a central aperture through which the end of a threaded conrod 174 locates and is mounted by means of nuts 176. As described above, the conrod 174 is in turn fitted to an internally threaded anchoring insert at one end of a coil spring assembly.

Turning now to Figures 11 and 12, a fifth embodiment of a second connection means 178 is shown for connecting the opposite end of the coil spring rearwardly of a conventional axle mounting arrangement 180. The axle mounting arrangement 180, includes a pair of U-bolts 182 and a rubber block 184 around which the U-bolts extend for securing the leaf spring pack 186 to the vehicle's axle 188. The connection means 178 includes a rectangular, substantially flat base plate 190, terminating at one end in a pair of upwardly extending side plates 192 and 194. The side plates 192 and 194 are held together in a spaced apart relationship by a mounting bolt 196, a corresponding lock nut 198, and a tubular spacer 200. The bolt 196 passes through the booked ends of a pair of anchor rods 202, thereby allowing the rods 202 to rotate around an axis 204 defined by the bolt 196 when the leaf spring pack 186 is flexed. The anchor rods 202 are in turn fixed to an anchor rod bracket 100 via mounting nuts 102, as described above with reference to Figures 3 and 4.

The primary advantage of the embodiments illustrated in Figures 9 to 12 is that, by allowing the conrod 174 and anchor rods 202 to rotate, stresses on the components of the connection means are reduced. This is particularly important for vehicles that are fitted with relatively strong coil springs, for allowing them to cope with loads up to, for example, 2 tons.

Claims (4)

1. Connection means for connecting a vehicle supplementary spring assembly to a leaf spring assembly, the leaf spring assembly being mounted to an axle of the vehicle by an axle mounting arrangement, with the supplementary spring assembly including an elongate coil spring, wherein the connection means connects a second end of the coil spring to a portion of the leaf spring assembly extending rearwardly of the axle mounting arrangement, with the connection point between the connection means and the second end of the coil spring overlying the axle mounting arrangement.

2. Connection means according to claim 1 wherein the connection means comprises a pair of side plates including spanning means for joining the side plates in a rigid spaced apart relationship.

3. Connection means according to claim 2 wherein the spanning means include lower and upper spacer elements which extend between the side plates, with the lower spacer element being arranged to bear against an undersurface of the leaf spring assembly and the upper spacer element being located above the axle mounting arrangement so as to define the connection point.

4. Connection means according to claim 3, which includes an intermediate spacer element which is arranged to bear against an upper surface of the leaf spring assembly, wherein the intermediate spacer element and the lower spacer element define anchoring means for anchoring the connection means to the leaf spring assembly so that a predetermined clearance exists between the connection means and a rearmost portion of the axle mounting arrangement. -13- A vehicle supplementary spring assembly for supplementing the spring force provided by a leaf spring assembly, with at least one end of the leaf spring assembly terminating in an eye arrangement, the leaf spring assembly being mounted to an axle of the vehicle by an axle mounting arrangement, the supplementary spring assembly comprising: an elongate coil spring; first connection means for connecting a first end of the coil spring to the eye arrangement of the leaf spring; and second connection means for connecting a second end of the coil spring to a portion of the leaf spring assembly extending rearwardly of the axle mounting arrangement, wherein the connection point between the second connection means and the second end of the coil spring overlies the axle mounting arrangement.