AU2002313837B2

AU2002313837B2 - Improvements to concrete mixer frames

Info

Publication number: AU2002313837B2
Application number: AU2002313837A
Authority: AU
Inventors: Kevin Joseph Forbes
Original assignee: MIXERS AUSTRALIA Pty Ltd
Current assignee: MIXERS AUSTRALIA Pty Ltd
Priority date: 2001-12-07
Filing date: 2002-12-05
Publication date: 2005-08-11
Anticipated expiration: 2022-12-05

Description

P/00/011I Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "IMPROVEMENTS TO CONCRETE MIXER FRAMES" The following statement is a full description of this invention, including the best method of performing it known to us: 2 TITLE: IMPROVEMENTS TO CONCRETE MIXER FRAMES BACKGROUND OF THE INVENTION 1. Field of the Invention THIS INVENTION relates to concrete mixer frames.

The invention also relates, but is not limited to, slip joint assemblies for the rails of concrete mixer frames; and concrete mixer frame rails incorporating the slip joint assemblies.

2. Prior Art In the early 1990's, the pre-mixed concrete industry forced truck and concrete mixer manufacturers to build lighter units to increase load carrying capacity. Over this period, the mixers have changed slightly in the chassis rail and mounting design, with the main weight savings being in the A-frame, pedestal, bowl and bolt-on accessories. The main changes to the trucks were lighter truck chassis.

The result from the changes to the lighter truck chassis has greatly reduced the life of the mixer frames, due to cracking around the pedestal, A-frame and/or chassis rails.

More recently (within the last 2-3 years), the truck manufacturers have introduced air bag suspension on the rear of the trucks, being supposedly more road friendly, and with mass management, allowing higher gross vehicle masses (GVM) on the trucks.

3 Unfortunately, in the majority of trucks fitted with air bag suspension, the mixer frame rails have cracked, and in some cases, broken away altogether, in a short period of time. The mixer manufacturers around Australia are trying to build mixers to withstand the flexing of the truck chassis and, to date, have proved unsuccessful.

SUMMARY OF THE INVENTION It is an object of the present invention to provide improvements to concrete mixer frames capable of withstanding, or ameliorating the effects of, the flexing of the truck chassis.

It is a preferred object of the present invention to provide concrete mixer frames which can effectively increase the rigidity of the truck chassis to minimise the flexing thereof.

It is a further preferred object of the present invention to provide improvements to the frames which, when the flexing of the chassis occurs, can compensate for the flexing without cracking or other mechanical failure.

It is a further preferred object of the present invention to provide slip-joint assemblies which may be incorporated in the frame rails.

It is a still further preferred object of the present invention to provide mixer frame rails incorporating at least one of the slip joint assemblies.

4 Other preferred objects of the present invention will become apparent from the following description.

In one aspect, the present invention resides in a slip-joint assembly for a concrete mixer frame rail including: a body engageable with an end of a first rail member; a sliding block, on the body, receivable in, and or engageable around, an adjacent end of a second rail member; and tension means interconnecting the first and second rail members; so arranged that the tension means urge the first and second rail members towards each other.

Preferably, resilient compression means are engaged by the tension means, the resilient compression means permitting at least limited axial movement of the second rail member relative to the first rail member.

While the body may be fixed or mounted to the first rail member, the body may have a second sliding block receivable in, or engageable around, the end of the first rail member.

Preferably, at least the end of the first rail member and the adjacent end of the second rail member are hollow square, rectangular, circular or other shape in end section); and preferably, the or each sliding block is a solid block, or of cup shape, and is operable to be slidably received within the end or adjacent end.

Preferably, the tension means includes at least one rod, bolt, cable, chain or the like; and, preferably the tension means incorporates means to enable the tension applied to the rail members to be selectively adjusted.

Preferably, the compression means includes a resilient rubber (or elastomeric), plastics or other deformable material block, or compression spring means helical coil or Belleville springs). The deformable material of the block may incorporate reinforcing plates, fibres or the like.

In a second aspect, the present invention resides in a concrete mixer frame rail having at least first and second rail members interconnected by at least one of the slip joint assemblies hereinbefore described.

Preferably, the frame rail has three rail members, where slip-joint assemblies (as hereinbefore described) are provided between first and second rail members, and second and third rail members, respectively.

In a third aspect, the present invention resides in a concrete mixer frame rail including: a first rail member; a second rail member spaced from, and substantially aligned with, the first rail member; and tension means interconnecting the first and second rail 6 members; so arranged that the tension means flexibly interconnect the first and second rail members together.

Preferably, resilient compression means are engaged by the tension means, to permit at least limited axial movement of the second rail member relative to the first rail member.

In fourth and fifth aspects, the present invention resides in a concrete mixer frame of the type having a pair of side rails (optionally interconnected by end rails) wherein each of the side rails is a frame rail as hereinbefore described with respect to the second and third aspects, respectively, of the invention.

In sixth and seventh aspects, the present invention resides in a concrete mixer assembly, mountable on the chassis of a truck or other prime mover, the concrete mixer assembly including: a concrete mixer frame as hereinbefore described with respect to the fourth and fifth aspects, respectively, of the present invention; a pedestal at one end of the frame; an A-frame at the other end of the frame; a concrete mixer bowl rotatably supported by the pedestal and the A-frame; and means operable to drive the mixer bowl.

Preferably, the side rails of the frame are secured to respective chassis rails of the truck or prime mover by U-bolts or other suitable releasable securing means.

BRIEF DESCRIPTION OF THE DRAWINGS To enable the invention to be fully understood, preferred embodiments will now be described with reference to the accompanying drawings, in which: FIG. 1 is a side elevational view of a concrete mixer having a frame in accordance with a first embodiment of the present invention; FIG. 2 is a front elevational view of the frame and pedestal (and associated components); FIG. 3 is a side view of the body and sliding blocks for a slip-joint assembly of a first embodiment; FIG. 4 is an end elevational view corresponding to FIG. 3; FIG. 5 is a side elevational view of an anchor plate and compression block for the slip-joint assembly; FIGS. 6 to 8 are views corresponding to FIGS. 3 to 7, of an alternative embodiment; FIG. 9 is a sectional side view of a portion of a frame rail in accordance with a second embodiment; FIG. 10 is a sectional side view of a slip joint on an enlarged scale; and FIG. 11 is a side elevational view of a concrete mixer having a frame in accordance with a third embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, the concrete mixer adapted to be mounted on a truck chassis C, has a frame 11 with a pair of side rails 12, 13, which are interconnected at their forward ends by a pedestal 14 which supports the drive motor 15 and drive assembly 16 for the concrete mixer bowl 17. At the rear of the frame 11, an A-frame 18 supports trunnion rollers (not shown) which engage a roller track 20 on the bowl 17 (adjacent its mouth) to rotatably support the bowl 17. Batched ingredients for the concrete can be fed to the interior of the bowl 17 by an inlet chute 22 and the mixed concrete is discharged via a discharge chute 23.

Each of the frame side rails 12, 13 has three side rail members 30, 31, 32, of rectangular RHS section where adjacent pairs of the rail members 30, 31 and 31, 32 are interconnected by slip-joint assemblies 40 to be hereinafter described in more detail.

Referring to FIGS. 3 and 4, the slip-joint assembly interconnects the adjacent ends of rail members 30, 31 as shown in dashed lines.

A rectangular body plate 41 has respective sliding blocks 42, 43 on opposed sides thereof, the sliding blocks 42, 43 being adapted to be slidably received within the ends of the rail members 31, with limited sliding clearance. Preferably, the body 41 and blocks 42, 43 are manufactured from stainless steel. A pair of bores or holes 44 extend through the body plate 41 and the blocks 42, 43 to receive the tension members to be hereinafter described. (In an alternative embodiment, not shown, the sliding blocks 42, 43 may be formed of a cup like arrangement with peripheral walls engaging the inner faces of the ends of the rail members 30, 31.) Adjacent the ends of the frame rails 12, 13, support blocks 50 (see FIGS. 5 and 6) are welded in the rail members 30, 32 and have holes or bores 51 therein.

The support blocks 50 support a respective rubber compression block 60, having holes or bores 61 therethrough aligned with the holes or bores 51. Preferably, the external dimensions of the compression blocks 60 are slightly reduced relative to the external dimensions of the mounting blocks 50 to allow some lateral expansion of the compression blocks 60, as they are placed under compression by the tension members (to be hereinafter described).

In the embodiments shown in FIGS. 3 to 5, a pair of tension members 70 are provided for each frame rail 12, 13.

However, as illustrated in FIGS. 6 to 8, a single tension member may be provided within each frame rail 12, 13.

Each tension member 70 has a rod (or cable) which extends through the holes or bores 44, 51, 61 and is provided with tensioning nuts 71 at the ends. The tensioning nut(s) 71 bears on a compression plate (not shown) which sandwiches a compression block between the compression plate and the support block 50. When there is no twisting or flexing of the vehicle chassis, the tension members 70 urge the rail members 30, 31 and 31, 32 into engagement with the body plates 41 of the respective slip joint assemblies If the truck chassis should twist or flex for any reason, eg., when passing over a large bump or hole in the road, the frame rails 12, 13 can accommodate the flexing by allowing limited axial movement between the adjacent rail members 30, 31 and 31, 32 at each slip-joint assembly 40, where adjacent rail members can slidably move along the sliding blocks 42, 43, against the compressive forces generated by the compression of the respective compression blocks in the frame rails 12, 13. The compression blocks 60 and the tension members 70 operate to restore the frame rails to their original position when the truck chassis has returned to its original position.

As the frame rails 12, 13 are bolted (or otherwise fixed) to the vehicle chassis rails, and are maintained under tension by the tension members 70, they operate to increase the rigidity (resistance to flex) of the vehicle chassis/mixer frame combination. However, the provision of the slip-joint assemblies 40 enables the mixer frame 11 limited flexibility/mobility to allow the truck chassis to flex without failure or damage cracking) of the frame rails 12, 13.

11 The compression blocks 60 may be formed of any suitable resilient material, eg., rubber, plastics, and may incorporate internal reinforcement and/or may be provided by compression springs, such as helical coil springs.

The tension members 70 may include rods, cables, chains or other like means able to apply tension to the rail members 31, 32.

Intermediate spacer blocks 80 may be provided within the frame rails 12, 13 to maintain the alignment of the tension members As shown in FIGS. 6 to 8, only a single tension member may be provided in each frame rail 12, 13. As shown, tensioning nut 71a bears on a compression plate 72a which engages the compression block Preferably, removable end caps 90a are provided at the ends of the frame rails 12, 13 to provide access to the tension nuts 71a to enable the tension applied by the tension member 70a to be selectively adjusted.

FIGS. 9 and 10 illustrate a modified embodiment of the first embodiment of FIGS. 2 to 6, where the slip-joint assemblies have their body plates 41b welded (or otherwise fixed) to an end of the side rails 12, 13 and a sliding block 42a is received in the adjacent end of the other side rail and is sealed thereto by an O-ring Referring now to the fourth embodiment of FIG. 11, there 12 is no "direct" connection between the adjacent ends of the first and second side rail members 130, 132 of the side rails 112, 113.

At least one tension member 170 extends through the side rail members 130, 132 and is provided with a compression block 160 at one end, or both ends, thereof.

This arrangement allows a higher degree of vehicle chassis flex or bend than the embodiments of FIGS. 1 to 10, while still ensuring adequate support for the mixer bowl 17.

In all of the embodiments, the compression means (eg., compression block 60, 60a, 160) can be eliminated if the material(s) of the tension member(s) 70, 70a,170 is/are selected so as to provide sufficient "stretch" when the vehicle chassis flexes/bends, while maintaining the desired tension force on the rail members.

Various changes and modifications may be made to the embodiments described and illustrated without departing from the present invention.

Claims

1. A slip joint assembly for a concrete mixer frame rail including: a body engageable with an end of a first rail member; a sliding block, on the body, receivable in, and or engageable around, an adjacent end of a second rail member; and tension means interconnecting the first and second rail members; so arranged that the tension means urge the first and second rail members towards each other.

2. A slip joint assembly as claimed in Claim 1 wherein: resilient compression means are engaged by the tension means, the resilient compression means permitting at least limited axial movement of the second rail member relative to the first rail member.

3. A slip joint assembly as claimed in Claim 1 or Claim 2, wherein: the body is fixed or mounted to the first rail member, or the body has a second sliding block receivable in, or engageable around, the end of the first rail member.

4. A slip joint assembly as claimed in any one of Claims 1 to 3 wherein: at least the end of the first rail member and the adjacent ends of the second rail member are hollow, being square, rectangular, 14 circular or other shape in end section; and the or each sliding block is a solid block, or of cup shape, and is operable to be slidably received within the end or adjacent end. A slip joint assembly as claimed in any one of Claims 1 to S 4 wherein: the tension means includes at least one rod, bolt, cable or chain and the tension means incorporates means to enable the tension applied to the rail members to be selectively adjusted.

6. A slip joint assembly as claimed in Claim 2 wherein: the compression means includes a resilient rubber, or elastomeric, plastics or other deformable material block, or compression spring means such as helical coil or Belleville springs, and the deformable material of the block optionally incorporates reinforcing plates, fibres or the like.

7. A concrete mixer frame rail having at least first and second rail members interconnected by at least one of the slip joint assemblies as claimed in any one of Claims 1 to 6.

8. A frame rail as claimed in Claim 7 wherein: the frame rail has three rail members, where the slip-joint assemblies are provided between first and second rail members, and second and third rail members, respectively.

9. A concrete mixer frame of the type having a pair of side rails (optionally interconnected by end rails) wherein each of the side rails is a frame rail as claimed in Claim 7 or Claim 8. A concrete mixer frame including: a first rail member; a second rail member spaced from, and substantially aligned with, the first rail member; and tension means interconnecting the first and second rail members; so arranged that the tension means flexibly interconnect the first and second rail members together.

11. A frame rail as claimed in Claim 10 wherein: resilient compression means are engaged by the tension means, to permit at least limited axial movement of the second rail member relative to the first rail member.

12. A frame rail as claimed in Claim 10 or Claim 11 wherein: the tension means includes at least one rod, bolt, cable or chain and the tension means incorporates means to enable the tension applied to the rail members to be selectively adjusted.

13. A frame rail as claimed in Claim 11, or Claim 12 when dependent on Claim 11, wherein: the compression means includes a resilient rubber, or elastomeric, plastics or other deformable material block, or compression spring means such as helical coil or Belleville springs, and the deformable material of the block optionally incorporates reinforcing plates, fibres or the like.

14. A concrete mixer assembly, mountable on the chassis of a truck or other prime mover, the concrete mixer assembly including: 16 a concrete mixer frame as claimed in any one of Claims 9 to 13; a pedestal at one end of the frame; an A-frame at the other end of the frame; a concrete mixer bowl rotatably supported by the pedestal and the A-frame; and means operable to drive the mixer bowl. A concrete mixer assembly as claimed in Claim 14, wherein: the side rails of the frame are secured to respective chassis rails of the truck or prime mover by U-bolts or other suitable releasable securing means.

16. A frame rail for a concrete mixer frame substantially as hereinbefore described with reference to FIGS. 1 to 6; or FIGS. 1, 2 and 6 to 8; or FIGS. 9 and 10; or FIG. 11, of the accompanying drawings.

17. A concrete mixer frame substantially as hereinbefore described with reference to FIGS. 1 to 6; or FIGS. 1, 2 and 6 to 8; or FIGS. 9 and 10; or FIG. 11, of the accompanying drawings. DATED this fifth day of December

2002. MIXERS AUSTRALIA PTY LTD By its Patent Attorneys FISHER ADAMS KELLY