AU2012205168C1

AU2012205168C1 - A Vehicle Ladder

Info

Publication number: AU2012205168C1
Application number: AU2012205168A
Authority: AU
Inventors: Bradley John Mccarthy; Mark Justin Serisier
Original assignee: Maxtrax Australia Pty Ltd
Current assignee: Maxtrax Australia Pty Ltd
Priority date: 2005-10-14
Filing date: 2012-07-17
Publication date: 2015-05-14
Anticipated expiration: 2026-10-13
Also published as: AU2012205168A1; AU2012205168B2

Abstract

Abstract The present invention relates to a vehicle ladder including an elongate single-piece molded body. The body defines at least one tire ramp and spaced apart supports 5 extending from the ramp. The body further defines traction members extending from the supports. ~-~ 55 Al 61 ? 55 Fq 1 55 5 2Fa

Description

1 A VEHICLE LADDER The present invention relates to a vehicle support or "ladder" for a vehicle. 5 Vehicle ladders find a variety of applications. Permanently or temporarily fixed ladders have been used to form vehicle tracks on soft or unprepared road bases. For example, over soft sand or other soft terrain, the National Parks authority forms tracks using laterally fixed timber lengths, so called "timber corduroy tracks". Similar constructions are often used for boat ramps and other soft or slippery 10 vehicle paths where traction is an issue. Corduroy tracks are relatively high maintenance requiring the timber lengths to be regularly replaced. In addition, corduroy tracks require a relatively large quantity of timber, only a relatively small quantity of which is actually used to support vehicles. Vehicle ladders also find use as recovery equipment for providing 15 improved traction in a form that can be placed in front of a vehicle's tyre to enable the vehicle to extricate itself from mud or soft sand. Examples of recovery ladders include sand ladders formed from lengths of aluminum or steel with holes pierced therethrough. This type of sand ladder is generally heavy and difficult to place in front of a tyre. In addition, in wet or muddy terrain these ladders provide little or no 20 traction. Other metal ladders have been formed from expanded mesh such as is used to form high grip walkways. However, such expanded mesh is generally deformed when used for the recovery of a 4WD, i.e. four-wheel-drive, vehicle. This is generally because in order for such a ladder to have sufficient strength to support a 25 4WD repeatedly it needs to be of a gauge that would render it too heavy for ready positioning in front of the wheels of a vehicle. Fibreglass gratings have also been used. However, wheel spin on this type of plastic grating generally results in the grating being heat effected, either in melting by friction the top surface of the grating or causing the grating to plastically 30 deform. An articulated series of plastic ribbed members that is light weight has been tried but provides little support for a vehicle.

2 Embodiments of the present invention provide a ladder for supporting a vehicle and providing traction that is light weight and cost effective or at least provides the user with a useful or commercial choice. 5 SUMMARY OF THE INVENTION According to a first aspect of the invention, there is provided a vehicle ladder including an elongate single-piece molded body, the body defining at least one tire ramp and spaced apart supports extending from the ramp, the body further defining 10 traction members extending from the supports, wherein each said support extends in line with the ramp. The supports may be straight strengthening ribs for imparting stiffness. The body may further define traction members extending from the ramp. Said at least one tire ramp may include a pair of tire ramps between which the supports extend. The 15 body may define at least one handle. The specification also describes a vehicle ladder including an elongate body having a topside into which a recessed portion is formed; and a plurality of traction members extending from a floor of the recessed portion. In a preferred embodiment opposing longitudinal strengthening ribs are 20 provided to imparting stiffness. The longitudinal strengthening ribs are preferably provided in the form of elongate trapezoidal sections. Braces may be formed across the underside of the longitudinal strengthening ribs in order to increase the strengthening ribs resistance to deformation due to the weight of a vehicle. Preferably a skirt is formed about a perimeter of the ladder to assist in 25 supporting the ladder in use. The skirt may have a perimeter that is non-linear, such as a serrated perimeter for example, in order to increase the ground traction. In order that the vehicle ladder may be readily handled and put into place it is preferable that it be formed with handholds. Similarly, the skirt may include a number of peg holes to assist in pegging the ladder to the ground in use for increased 30 traction. The apertures and holes through the support may provide a convenient fixing point with which to attach the vehicle ladder to a vehicle for transport, either on a roof rack or on a rear mounted spare wheel.

3 In a preferred embodiment the recessed portion is at least partly defined by the opposing longitudinal strengthening ribs. The strengthening ribs may extend longitudinally along the vehicle ladder to provide structural rigidity to the 5 vehicle ladder and assist in strengthening. The strengthening ribs may be in the form of an inverted channel or a tubular section generally dependent upon the manufacturing technique used to produce the vehicle ladder. The strengthening ribs may include internal bracing to reduce distortion of the ribs under load. The strengthening ribs may form part of the upper driving surface and optionally also 10 include one or more of the tread engaging projections for engaging with channels in a vehicle tyre tread pattern whereby the traction of the vehicle is enhanced. In such an embodiment the upper surface of the strengthening ribs will be at about the height of the traction members. Ramps may be formed at opposing ends for a vehicle wheel to roll 15 onto, or off, said ladder in use. In the preferred embodiment the sides of the recess are defined by the opposing longitudinal strengthening ribs and ends of the recess are defined by the ramps. Preferably the vehicle ladder includes a plurality of tread engaging projections extending from the topside which may be elongate and orientated non 20 parallel to a long-axis of the vehicle ladder. For example, they may be orientated at substantially ninety degrees, or forty-five degrees, to the long-axis in order to correspond to the tread pattern of a vehicle tire. The tread engaging projections are preferably disposed on upper surfaces of the traction members, strengthening ribs and ramps. 25 In a preferred embodiment the vehicle ladder is formed of a material of substantially constant thickness. The vehicle ladder may be formed from a variety of materials. For example, the vehicle ladder may be formed from timber, metal or plastic. The vehicle ladder is preferably formed from plastics materials in due to the ability of plastics materials to provide a lightweight yet tough support for the vehicle. 30 The vehicle ladder may be formed by injection moulding, preferably of a granulated fibre reinforced nylon compound. An injection moulded vehicle ladder may be formed as a stackable component. So as to be stackable, the ribs extending longitudinally may be 4 trapezoidal, and the traction members may be frustoconical. In addition to providing stackability, the inventor has found that such a configuration provides a vehicle ladder with increased strength. The thickness of the vehicle ladder will depend on the materials of 5 construction and the production process. The inventor has found that a suitable height is in the range of from 50 mm to 120 mm. Preferably the height of the vehicle ladder will be approximately 75 mm. The thickness of an injection moulded vehicle ladder is preferably about 8mm although the thickness will depend on the materials of construction and 10 the anticipated weight of the vehicle. Preferably the vehicle ladder is formed with an underside of a shape complementary to the topside in order that two or more of the vehicle ladders can be stacked one on top of the other. Stacking the ladders to form a lamination of them results in a composite ladder of increased strength which may be advantageous for use is with particularly heavy vehicles. Temporary applications of the vehicle ladder of the present invention preferably include vehicle recovery whereby the vehicle ladder is placed under or in front of a wheel of a vehicle whereby the wheel can gain traction on the ladder and advance the vehicle. Other temporary applications of the vehicle ladder include 20 providing a temporary ramp for a vehicle to traverse, so that an approach angle or departure angle can be reduced to within the range of the vehicle. The vehicle ladder of the present invention comprises a stiff vehicle ladder. It will be understood that the term "stiff' is used herein to refer to the ability of the vehicle ladder to bear the weight of the vehicle without undue deformation. It 25 will be appreciated that the vehicle ladder may flex to a limited degree and not be completely rigid but that the vehicle ladder should be sufficiently stiff so that the vehicle ladder does not simply deform about the wheel of the vehicle or to the shape of the terrain. The vehicle ladder of the present invention may be dimensioned to any 30 suitable size and is based upon the intended application. In fixed applications the vehicle ladder is preferably of sufficient width to enable a variety of vehicles to traverse the ladder. Each vehicle ladder that may be spaced apart to form a track should be sufficiently broad in size to enable a variety of vehicles to traverse the 5 ladder, with its left and right wheels supported upon the ladders. The length of the vehicle ladder in fixed applications maybe any convenient length as such applications will be generally constructed with machinery that will enable the lifting and manipulation of substantial sections and weight is not a critical problem. 5 Preferably the length of the vehicle ladder will be selected so that the vehicle ladder can be used to form tracks having a desired curvature. In order that the invention may be more fully understood and put into practice, preferred embodiments thereof will now be described with reference to the accompanying drawings. 10 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a perspective top view of a vehicle ladder according to a preferred embodiment of the present invention; Figure 2 shows an enlarged view of one end of the vehicle ladder 15 shown in figure 1; Figure 3 shows a plan view of a topside of the vehicle ladder of Figure 1; Figure 4 shows a plan view of an underside of the vehicle ladder of Figure 1; 20 Figure 5 shows a plan view of a tyre track which is superimposed on various traction members of the vehicle ladder of Figure 1. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT Figures 1 to 4 show an elongate vehicle ladder 51 in accordance with a 25 preferred embodiment of the present invention. The vehicle ladder 51 has a long axis in which direction a vehicle's wheels are intended to roll in use. Ladder 51 has a topside into which a recessed portion 48 is formed. A plurality of traction members 52 extend from the floor of the recessed portion to support a vehicle tire in use. Other traction members are disposed along the outside edges of the vehicle ladder. The 30 traction members 52 are frustoconical in shape with the traction members in the recessed portion of the vehicle ladder 51 being arranged in an array of rows and ranks. In the present embodiment, each row and each rank includes a triplet of traction members 52. There is further provided a pair of parallel rows of traction members 52 6 which are each located along either side of the vehicle ladder 51. At the tip of the traction members 52 extend respective projections 54 that comprise tread engaging members and are dimensioned to fit within a vehicle tyre tread channel. 5 The tread engaging members 54 are disposed generally at 90 and 45 degrees to the longitudinal axis of the vehicle ladder which is substantially in accordance with the channels of vehicle tyre tread patterns used in off-road vehicle applications such as 4WDs, quad-bikes and the like. Each pair of adjacent projections 54 in any given row or rank preferably have a different orientation. 10 The vehicle ladder 51 includes ramps 55 at either end. A pair of strengthening ribs in the form of elongate trapezoidal sections 56 extend along the vehicle ladder 51 between the ramps 55. The trapezoidal sections 56 enhance the stiffness of the vehicle ladder 51. The trapezoidal sections 56 extend longitudinally along the vehicle ladder 51 and include braces 57 spaced at regular intervals there 15 along so as to reduce the flattening effect of a heavy vehicle resting on the trapezoidal sections 56. The ramps and strengthening ribs, which in the present embodiment define the recess 48 tend to act as a barrier to mud and water entering the recess and building up around the traction members, and ultimately the tread engaging members, 20 which would result in a reduction of tire traction during use. The sides of the vehicle ladder 51 include a skirt 47 that runs along the outside of the strengthening ribs, and has edge sections 58 that have been serrated so that they are non-linear in order to increase the perimeter length of the vehicle ladder to thereby enhance ground traction. The underside of the vehicle ladder includes 25 projections 59 that are adapted to engage the ground and further enhance the traction between the vehicle ladder 51 and the ground. The vehicle ladder 51 also includes slotted apertures 60 that are used for hand holds so that the vehicle ladder can be easily manipulated by a user. Apertures 61 provide attachment points for the vehicle ladder 51. These apertures 61 30 facilitate tying the vehicle ladder 51 to a fixed object such as a tree (or an adjacent vehicle ladder 51) using rope. . The vehicle ladder 51 may also be pegged to the ground by inserting pegs through the apertures 61. Tread engaging members 54 are further provided which extend from 7 the ramps 55 and trapezoidal sections 56 to facilitate the gripping of a vehicle tyre. Two or more vehicle ladders 51 may be stacked together so as to form a support of increased stiffness. Figure 5 shows a plan view of a planar tyre track 72 (shown in dashed 5 lines) which is superimposed on the vehicle ladder of Figure 1. The location of a number of traction members 52 with respect to the tyre track is shown. In use, tread engaging members 54 are received within tyre channels 70 to thereby enhance tyre traction. Typically, not all of the tread engaging members 54 will engage with a 10 channel 70. However, at least some of the tread engaging members 54 typically engage with a channel 70 whilst others engage with the contact face of the tyre in which the channels 70 are defined. Vehicle ladder 51 is formed as a stackable component. As previously mentioned the strengthening ribs 56 are trapezoidal in cross section, and the traction 15 members 52 are frustoconical so that a number of similar vehicle ladders may be stacked on top of each other. In addition to providing stackability, the inventor has found that such a configuration provides a vehicle ladder with increased strength. The thickness of a vehicle ladder according to the present invention will depend on the materials of construction and the production process. The inventor 20 has found that a suitable height is in the range of from 50 mm to 120 mm. Preferably the height of the vehicle ladder will be approximately 75 mm. The thickness of an injection moulded vehicle ladder is preferably about 8mm although the thickness will depend on the materials of construction and the anticipated weight of the vehicle. 25 The use of the vehicle ladder 51 will now be described. In the event that a vehicle loses traction on slippery terrain, the vehicle may be stopped and one or more vehicle ladders 51 can be removed from stowage areas such as the boot, or roofrack, of the vehicle. The vehicle ladders 51 are relatively light and can be carried by placing a hand through a slotted aperture 60. 30 A vehicle ladder 51 can be placed under each wheel which is slipping. The vehicle ladder 51 is thrust axially under the wheel so as to jam a ramp 55 between the tyre and the ground. The vehicle ladder 51 may be further laterally reciprocated and pushed beneath the tyre to as to cause the serrated edges 58 to dig into the ground 8 for increased stability. Pegs may then be received in one or more apertures 61 to hold the vehicle ladder 51 fast with respect to the ground. The user can then return to his vehicle and slowly drive up the ramp 55 and along the vehicle ladder 51. 5 As discussed previously, for improved strength, a pair of vehicle ladders 51 may be stacked together and placed beneath a slipping wheel in accordance with the foregoing procedure. Persons skilled in the art will appreciate that the invention described above may be subject to improvements and modifications that will be apparent 10 without departing from the spirit and scope of the invention as set out in the following claims.

Claims

1. A vehicle ladder including an elongate single-piece molded body, the body defining at least one tire ramp and spaced apart supports extending from the ramp, the 5 body further defining traction members extending from the supports, wherein each said support extends in line with the ramp.

2. A vehicle ladder as claimed in claim 1, wherein the supports are straight strengthening ribs for imparting stiffness. 10

3. A vehicle ladder as claimed in claim 1 or claim 2, wherein the body further defines traction members extending from the ramp.

4. A vehicle ladder as claimed in any one of the preceding claims, wherein said at 15 least one tire ramp includes a pair of tire ramps between which the supports extend.

5. A vehicle ladder as claimed in any one of the preceding claims, wherein the body defines at least one handle. 20

6. A vehicle ladder as claimed in claim 5, wherein the body defines handles on opposite sides of the body.

7. A vehicle ladder as claimed in any one of the preceding claims, wherein the supports connect the ramp and the body further defines at least one recessed portion 25 between the supports.

8. A vehicle ladder as claimed in claim 7, further including traction members topping platforms extending from a floor of the recessed portion. 30

9. A vehicle ladder as claimed in any one of the preceding claims, wherein the body defines slotted apertures on either side of the supports, each aperture being elongate and extending along the body. 10

10. A vehicle ladder according to any one of the preceding claims, wherein each traction member engages at a respective position on a tire.

11. A vehicle ladder according to any one of the preceding claims, wherein each 5 traction member includes a planar tip.

12. A vehicle ladder according to claim 11, wherein the tips are arranged in more than one orientation. 10

13. A vehicle ladder according to claim I1 or claim 12, wherein the tips are orientated non-parallel to a long-axis of the vehicle ladder.

14. A vehicle ladder according to claim 13, wherein the tips are orientated at substantially ninety degrees, or forty-five degrees, to the long -axis. 15

15. A vehicle ladder according to any one of the preceding claims, wherein the supports are in the form of elongate trapezoidal sections.

16. A vehicle ladder according to claim 15, wherein the supports include braces.

17. A vehicle ladder according to any one of the preceding claims, further 20 including a skirt formed about a perimeter of the ladder to support the ladder in use.

18. A vehicle ladder according to any one of the preceding claims formed of a material of substantially constant thickness.

19. A vehicle ladder according to any one of the preceding claims having an underside of a shape complementary to a topside in order that two or more of the 25 vehicle ladders are stackable one on top of the other.

20. A vehicle ladder as claimed in any one of the preceding claims, and substantially as herein described with reference to the accompanying drawings.