TECHNICAL FIELD

[0001] The present invention relates to a vehicle recovery ladder. The present invention has particular, although not exclusive application to four-wheel drive (4WD) vehicles.

BACKGROUND

[0002] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

[0003] Four-wheel drive (4WD) vehicles invariably become stuck in sand and mud. Traditionally, shovels were used to dig and extricate stuck 4WD vehicles. Alternatively, timber could be jammed beneath tyres in an attempt to gain more wheel traction.

[0004] A known vehicle recovery ladder disclosed in AU 2010100831 provides improved traction when extricating vehicles. Advantageously, the ladder is light-weight being molded from polymeric material and includes traction members to assist the wheel in climbing out of the mire. However, the Applicant has perceived that the traction members can wear or melt in extreme circumstances, such as the spinning of a wheel, which can severely hamper the ongoing performance of the ladder.

[0005] Embodiments of the present invention provide an improved vehicle recovery ladder.

SUMMARY OF THE INVENTION

[0006] According to one aspect of the present invention, there is provided a vehicle recovery ladder including:

a body;

traction members for releasably fastening to the body. [0007] Advantageously, any damaged traction members may be readily released and replaced to maintain the performance of the ladder.

[0008] The traction members may be bonded to the body with a chemical and/or mechanical bond.

[0009] The traction members may be configured to not damage the tyre during use. Preferably, the traction members are less durable than a tyre so as to sustain damage before the comparatively more expensive tyre. The traction members may include polymeric material (e.g. elastomer, polyurethane, thermoplastic, nylon). The body may also include polymeric material (e.g. elastomer, polyurethane, thermoplastic, nylon). The traction members may include metal material (e.g. metal alloy), ceramic material or rubber material. In one embodiment, the body and the traction members are each intergrally formed (e.g. injection molded) from the same material.

[00010] Each traction member may include a rotational release means for rotationally releasing the traction member from the body. The rotational release means may include a thread. The rotational release means may include a tool recess for receiving a release tool. The recess may be hexagonal, pentagonal, octagonal, square, slotted, cross or star shaped.

[00011] The ladder may include locks for locking the traction members to the body. Each traction member may include an inhibiter for inhibiting unintentional release of the traction member from the body. The inhibitor may include one or more formations (e.g. tongue, groove, etc.). The inhibitor may include a tongue or groove.

[00012] The traction members may be released from the rear of the ladder.

Alternatively, the traction members may be released from the top of the ladder. Each traction member may include a skirt from which a tooth extends. Each traction member may be over-molded. Each traction member may include a thread located either above or below the skirt.

[00013] According to another aspect of the present invention, there is provided a traction member for a vehicle recovery ladder, the traction member including:

release means for releasing the traction member from the body. [00014] The release means may include rotation release means for releasing the traction member

[00015] According to another aspect of the present invention, there is provided a method for repairing a damaged traction member of a vehicle recovery ladder, the method involving:

releasing the traction member from a body of the ladder.

[00016] The step of releasing may involve rotating the traction member.

[00017] According to another aspect of the present invention, there is provided a vehicle recovery ladder including:

a body;

traction members bonded to the body.

[00018] The bonding may form a chemical and/or mechanical bond. The chemical bond may be formed by crosslinking of body and traction member materials. The chemical bond may be broken to release the traction members from the body. The mechanical bond may include engaged threads.

[00019] According to another aspect of the present invention, there is provided a method of forming a vehicle recovery ladder, the method including the steps of:

locating traction members in a mold; and

molding a body to form a bond with the traction members.

[00020] The method may involve molding the traction members in another mold. The traction members located in the mold may be set prior to molding the body. The traction members may have a lower melting point than the body to facilitate chemical bonding between the traction members and the body.

[00021] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS [00022] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[00023] Figure 1 a is a plan view of a vehicle ladder in accordance with an

embodiment of the present invention;

[00024] Figure 1 b is a side sectional view of the vehicle ladder of Figure 1 a;

[00025] Figure 1 c is a side view of the vehicle ladder of Figure 1 a;

[00026] Figure 2 is a close-up sectional view of the circular inset in Figure 1 a showing various types of traction members in accordance with embodiments of the present invention;

[00027] Figure 3a is an upper perspective view of a first traction member shown in Figure 2;

[00028] Figure 3b is a lower perspective view of a first traction member shown in Figure 2;

[00029] Figure 4a is an upper perspective view of a second traction member shown in Figure 2;

[00030] Figure 4b is a lower perspective view of a second traction member shown in Figure 2;

[00031] Figure 5a is an upper perspective view of a third traction member shown in Figure 2; and

[00032] Figure 5b is a lower perspective view of a third traction member shown in Figure 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [00033] According to an embodiment of the present invention, there is provided a vehicle recovery ladder 100 as shown in Figure 1 . The ladder includes an elongate molded body 1 02, and molded traction members 104 that are releasably fastened to the body 104. The traction members 104 are bonded to the body 102 with a chemical and mechanical bond formed during molding. Advantageously, any damaged traction members 104 can be readily released and replaced to maintain the performance of the ladder 100.

[00034] The traction members 104 are normally less durable than a vehicle tyre so as to sustain damage before the comparatively more expensive tyre. The traction members 104 are formed from polymeric material (e.g. elastomer, polyurethane, thermoplastic, nylon). The body 102 is also formed from polymeric material (e.g. elastomer,

polyurethane, thermoplastic, nylon). Typically, the body 102 and the traction members 104 are each intergrally formed (e.g. injection molded) from the same material.

[00035] Figure 2 shows four types of traction member 104, namely: novel first, second and third traction members 104a, 104b 104c; and a conventional traction member 104d integrally formed with the body 102. In practice, the ladder 100 would usually consist of the same type of traction member 104.

[00036] The traction members 104a, 104b 104c can be clearly seen in Figures 3 to 5 respectively. Each traction member 104 includes a rotational release for rotationally releasing the traction member 104 from the body 102. The rotational release includes a thread 300. The rotational release also includes a hexagonal tool recess 302 for receiving a release tool (e.g. Allan key).

[00037] The ladder 100 includes tongue-in-groove locks for locking the traction members 104 to the body 102. In particular, each traction member 104 includes an inhibiter 304 for inhibiting unintentional release of the traction member 104 from the body 102. The inhibiter 304a of the first traction member 104a is a topside tongue for sitting in a complementary groove of the body 102. The inhibiter 304b of the second traction member 104b is an underside groove in which a complementary tongue of the body 102 sits. The inhibiter 304c of the third traction member 104c is an underside groove in which a complementary tongue of the body 102 sits. [00038] Returning to Figure 2, the traction member 104a is released from the rear or underside of the ladder 100. Alternatively, the traction members 104b, 104c are released from the topside of the ladder 100. Each traction member 104 includes a broad skirt 200 from which a tooth 202 upwardly extends. Each tooth is flanked by a pair of support fillets 306 (see. Fig 3). As can best be seen in Figure 2, each traction member 104 is over-molded by the body 102 to give increased breadth.

[00039] A method of forming the vehicle recovery ladder 100 is now described.

[00040] Firstly, the traction members 104 are injection molded in a traction member mold and permitted to set before removal.

[00041] Next, the set traction members 104 are positioned in a ladder mold.

[00042] Next, the body 102 is injection molded into the ladder mold and a chemical bond forms between the traction members 104 and body 102. A mechanical bond forms with engaging threads of the body 102 and traction members 104. As shown in Figure 2, the body 102 is overmolded over the embedded traction members 104 and forms a complementary thread with the traction members 104. The traction members 104 may have a lower melting point than the body 102 to facilitate chemical bonding between the traction members 104 and the body 102. The chemical bond is formed by crosslinking of the traction member and body materials.

[00043] In use, the chemical and mechanical bond is broken when releasing the traction members 104 from the body 102. Another traction member 104 can be threaded into the body 102 to replace a released traction member 104.

[00044] A person skilled in the art will appreciate that many embodiments and variations can be made without departing from the ambit of the present invention.

[00045] The traction members 104 may be formed from metal material (e.g. metal alloy), ceramic material or rubber material.

[00046] In one embodiment, the traction members 104 may be formed of a different material to the body 102 to suit the particular application (e.g. hard metal teeth for military operations). The traction members 104 may be permanently bonded to, and not releasable from, the body 102.

[00047] The recess 302 may be pentagonal, octagonal, square, slotted, cross or star shaped.

[00048] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect.

[00049] Reference throughout this specification to One embodiment' or 'an

embodiment' means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases 'in one embodiment' or 'in an embodiment' in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.