AU674116B2 - Stub axle replacement unit - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: JOHN CHARLES BOOTH 2/10 Buzolic Court CARNARVON WA 6705 JOHN CHARLES BOOTH 2/10 Buzolic Court CARNARVON WA 6107 o oe o*o ooo ooe eo *P Standard Complete Specification for the invention entitled: STUB AXLE REPLACEMENT UNIT Details of Associated Provisional Applications: PM 9324 filed on 9 November 1994 Details of Parent Application for Divisional Applications: The following is a full description of this invention, including the best method of performing it known to me:- 2 STUB AXLE REPLACEMENT UNIT The present invention relates to a stub axle replacement unit for replacing a broken or damaged axle stub of a towable vehicle such as a trailer or caravan.

In many parts of Australia, particularly in the more isolated outback areas, road surface conditions can be very poor. Dirt roads in particular can become badly potholed and/or extremely corrugated due to rain and infrequent maintenance. Poor road surface conditions place additional stresses and strains on motor vehicles and on trailers and caravans being towed by motor vehicles. The suspension on trailers and caravans is not designed to cope with the repeated impact caused by pot-holes, and the high levels of vibration caused by corrugations. Hence, it is not uncommon, particularly with heavily loaded trailers and caravans, for a failure to occur in the vehicle's suspension and/or axle.

When such a failure occurs it is not normally possible to continue to tow the vehicle. In addition to the inconvenience of preventing further travel, it can also take many days to locate and transport a suitable spare or replacement part in such isolated and sparsely populated areas.

Australian Patent Specification No. 66,511/60 ooos describes an improved trailer and caravan axle which is designed to overcome this problem. The axle of 66,511/60 S.o. comprises two sections of equal length adapted to be coupled e together in co-linear relationship by means of a sleeve formed integral with the end of one section, or by means of a separate sleeve. Should one of the sections break, it is 30 a relatively simple matter to replace it by undoing and withdrawing the broken section from the sleeve, and replacing it with a spare one carried for this purpose. One of the problems with the axle of 66,511/60 is that it requires a substantial modification of the trailer or caravan prior to departure, in that the conventional one-piece axle of most trailers must be replaced with the two-part axle and sleeve 3 arrangement of 66,511/60. A further disadvantage is that the spare axle half is a relatively long and heavy component which adds weight and takes up storage space in the towing vehicle or in the trailer/caravan.

The applicant has found that most trailer/caravan axles break close to one end in the vicinity of the springs and/or the axle stub. The axle stub is that part of the axle on which the wheel hub is rotatably mounted. Therefore, the present invention was developed with a view to providing a stub axle replacement unit which is compact and relatively light-weight and which can be more conveniently carried as a spare part.

According to the present invention there is provided a stub axle replacement unit for replacing a broken or damaged axle stub of a towable vehicle, such as a trailer or caravan, the unit comprising: a sleeve member adapted to be fitted over an end of the vehicle axle and provided with means for securing the unit to the end of the vehicle axle; and, an axle stub fixed to said sleeve member and adapted to receive a wheel hub of the vehicle thereon.

In one embodiment said sleeve member is of square hollow cross-section. Preferably said means for securing the unit to the end of the vehicle axle comprises a threaded bolt eo 25 threadedly received in a wall of the sleeve member and S" adapted to clamp the sleeve member to the end of the vehicle axle. Preferably, said threaded bolt is one of two such *bolts provided extending through opposite side walls of the sleeve member for securing the sleeve member to the end of 30 the vehicle axle. Preferably both of said threaded bolts are .provided with a lock nut for locking the bolts in a tightened position.

5In another enbodiment the replacement unit also includes a wheel hub fitted to the axle stub and adapted to receive a wheel of the towable vehicle thereon.

Advantageously the replacement unit with hub attached can be used for holding the spare wheel in place as well as being a 4 breakdown part, thus reducing the need for additional internal storage space within the vehicle.

In order to facilitate a better understanding of the invention a preferred embodiment of the stub axle replacement unit will now be described in detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of one embodiment of the stub axle unit; Figure 2 is a plan view of the stub axle unit of Figure 1; and, Figure 3 is a side view of the stub axle unit of Figure 1.

The preferred embodiment of the stub axle replacement unit 10 illustrated in Figures 1, 2 and 3 comprises a sleeve member 12 adapted to be fitted over an end of a vehicle axle (not illustrated), and an axle stub 14 fixed to the sleeve member 12 and adapted to receive a wheel hub (not illustrated) of a vehicle thereon. The sleeve member 12 is provided with first and second threaded bolts 16 for securing the unit 10 to the end of the vehicle axle. As *can be seen most clearly in Figure 1, sleeve member 12 of 0 this embodiment is manufactured from rectangular hollow section steel with internal dimensions slightly larger than the external dimensions of the axle bar for the trailer or caravan. Many trailers and caravans are fitted with an axle bar of square cross-section having an axle stub of circular cross-section provided at each end. The axle stub 14 of the replacement unit 10 is of similar shape and configuration to the axle stub of the vehicle axle it is designed to replace.

Axle stub 14 is securely welded to one end of the steel sleeve member 12.

Most of the forces producing stresses and strains in the vehicle axle are transmitted from the vehicle wheels via the axle stub to the rest of the axle and to the vehicle's suspension. The axle bar is normally clamped to the springs adjacent each end near the axle stubs. Hence, it 5 is in this region that most of the stresses and strains on the vehicle axle are located and where breakage or damage is most likely to occur.

In the event of axle failure, and assuming the breakage or damage has occurred in the region of the axle stub or immediately adjacent thereto, the damaged or broken end of the axle bar is sawn off using a steel hacksaw. The stub axle replacement unit 10 is then fitted to the vehicle axle by slipping the sleeve member 12 over the end of the vehicle axle. The unit is securely held on the end of the vehicle axle by tightening the bolts 16 so that they clamp the sleeve member 12 to the end of the vehicle axle. Lock nuts 18 are provided to lock the bolts 16 in the tightened position so as to prevent them from loosening due to vibration. The wheel hub can then be refitted to the axle stub 14 of the replacement unit, and the vehicle wheel fitted to the hub. The journey may then be continued and the trailer/caravan used as normal until such time as the whole axle can be replaced. The replacement unit 10 can then be recovered from the damaged axle and stowed in the vehicle for future use.

The illustrated embodiment is provided with a short length of chain 24 welded to the sleeve member 12 to enable the replacement unit 10 to be chained to the towable vehicle's axle suspension. A right angle bracket 20 is welded to a side wall of the sleeve member 12 and has a thin threaded bolt 22 and nut fitted thereto to receive a link of the chain 24 thereon. This arrangement provides an optional safety feature for the replacement unit 10. In use, when the unit 10 has been clamped to the end of the vehicle axle as :described above, chain 24 is wound around the adjacent vehicle spring and bolt 22 is passed through one of the links of the chain 24 and fastened to bracket 20 by the nut on bolt 22. Hence in the unlikely event that one or both of bolts 16 come loose, the stub axle replacement unit 10 is still retained securely on the end of the vehicle axle by chain 24.

Clearly, although the sleeve member 12 is of 6 rectangular hollow section steel, it can also be used with axle bars of circular cross-section, provided the outside diameter of the axle bar is smaller than the internal dimensions of the sleeve member 12. Alternatively, the sleeve member 12 can be manufactured from a short length of round hollow section steel pipe if preferred. In any case, both the sleeve member 12 and the axle stub 14 may be manufactured in any desired size corresponding to the stub axle of the trailer/caravan it is designed as a temporary replacement part for. Sleeve member 12 is typically approximately 70 mm to 120 mm in length.

Since the overall length of the replacement unit is relatively short, the entire unit is sufficiently compact and light-weight to be easily stowed in the boot of the towing vehicle. Alternatively, the stub axle replacement unit 10 may itself be used on the trailer/caravan or on the towing vehicle as a mounting for a spare vehicle wheel. The trailer/caravan or towing vehicle is provided with a short protrusion to which the replacement unit 10 can be secured.

If desired, the replacement unit 10 may be fitted with its own replacement hub as well. The spare wheel may then be bolted to the replacement hub so that the replacement unit performs a useful function even when it is not being used to replace a broken or damaged axle stub.

Now that a preferred embodiment of the stub axle replacement unit according to the invention has been described in detail, it will be apparent that the described unit 10 provides a number of advantages, including the following: It can be sold separately in various stub axle sizes, complete with correct size hub fitted to it if desired.

It can be modified to suit both square or round a. axles in all existing vehicle sizes.

It is less expensive and more convenient to the user than purchasing and carrying around a whole new vehicle axle in case of breakdown.

7 It is compact and versatile. A complete replacement unit with hub attached can be used for holding the spare wheel in place as well as being a breakdown part, thus reducing the need for additional internal storage space within the vehicle.

Numerous variations and modifications will suggest themselves to persons skilled in the mechanical arts, in addition to those already described, without departing from the basic inventive concepts. For example, other methods of securing the sleeve member 12 to the end of the vehicle axle may be used. Furthermore, although the above described stub axle replacement unit is designed to temporarily replace a damaged or broken stub axle on a conventional vehicle axle, the replacement unit may also form a permanent part of a nonconventional axle system. In such a non-conventional system, the axle bar is fitted with a replaceable stub axle unit similar to that described above at each end. When either unit is damaged or broken it can be readily replaced with a replacement unit carried for this purpose. All such variations and modifications are to be considered within the scope of the present invention, the nature of which is to be determined from the foregoing description and the appended a claims.

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Claims (10)

1. A stub axle replacement unit for temporarily replacing a broken or damaged axle stub of a towable vehicle such as a trailer or caravan, the unit comprising: a sleeve member adapted to be fitted over an end of the vehicle axle and provided with means for securing the unit to the end of the vehicle axle; and, an axle stub fixed to said sleeve member and adapted to receive a wheel hub of the vehicle thereon.

2. A stub axle replacement unit as defined in claim 1, wherein said sleeve member is of square hollow cross-section.

3. A stub axle replacement unit as defined in claim i, wherein said sleeve member is of circular hollow cross- section.

4. A stub axle replacement unit as defined in any one of claims 1 to 3, wherein said means for securing the unit comprises a threaded bolt threadedly received in a wall of :the sleeve member and adapted to clamp the sleeve member to :the end of the vehicle axle. 20

5. A stub axle replacement unit as defined in claim 4, CC CO S•wherein said threaded bolt is one of two such bolts provided extending through opposite side walls of the sleeve member cfor securing the sleeve member to the end of the vehicle i axle. O QI e 25

6. A stub axle replacement unit as defined in claim cOI6O S"wherein both of said threaded bolts are provided with a lock **nut for locking the bolts in a tightened position. C

7. A stub axle replacement unit as defined in any one of the preceding claims, wherein said means for securing the unit further comprises a short length of chain fixed to a 9 side wall of the sleeve member for securing the unit to the vehicle suspension.

8. A stub axle replacement unit as defined in claim 7, wherein a bracket is fixed to a side wall of the sleeve member and is provided with means for fastening a link of the chain to the bracket.

9. A stub axle replacement unit as defined in any one of the preceding claims, further comprising a wheel hub fitted to the axle stub and adapted to receive a wheel of the towable vehicle thereon. A stub axle replacement unit substantially as herein described with reference to and as illustrated in the accompanying drawings. Dated this 30th day of October 1995 JOHN CHARLES BOOTH By His Patent Attorneys GRIFFITH HACK CO. Fellows Institute of Patent eooe Attorneys of Australia. 0*00 0* e o o .e I

10 ABSTRACT A stub axle replacement unit 10 for replacing a broken or damaged axle stub of a towable vehicle such as a trailer or caravan. The unit 10 comprises a sleeve member 12 adapted to be fitted over an end of the vehicle axle, and an axle stub 14 adapted to receive a wheel hub of the vehicle thereon. First and second threaded bolts 16 are provided in the sleeve member 12 for securing the unit 10 to the end of the vehicle axle. The unit is compact and versatile, is less expensive and more convenient to the user than purchasing and carrying around a spare vehicle axle in case of breakdown. 4 e 9 o o• o• 4 a* f