Field of the Invention

The present invention generally relates to a sliding apparatus for use on loading platforms and docks in order to minimise damage to the building, dock, bumper rubber and loading vehicles.

Background Art

At warehouses and stores, trucks are typically reversed up to a loading dock to allow goods to be loaded or unloaded from the truck. In reversing to the dock, trucks often engage the dock wall so as to minimise the distance between the dock and the truck. In order to protect the dock from vehicles, and vice versa, it is common practice to secure protruding protective rubber bumpers to the dock such that they engage the rear of the truck before the truck engages the dock. These bumpers protect both the building structure as well as the truck from damage.

Often goods are loaded or unloaded from the truck by trolleys or forklifts. As the truck is loaded or unloaded, the truck moves with respect to the dock due to the changes in load on the truck. As a result of this movement the truck rubs up and down the bumper, causing the bumper to deteriorate quite quickly, requiring regular replacement.

Several different types of systems used to attach bumpers to the dock are available which attempt to alleviate this problem. These systems generally have a bumper movably mounted on one or more guide rails, which in turn are secured to the dock. These systems permit the bumper to move in a vertical direction between two predetermined positions so as to accommodate the up and down movement of the truck relative to the dock. '

These systems typically incorporate springs which return the bumper to a set position when the truck disengages from the dock. One such system has a set of springs on guide rails secured to the dock wall, and which are located on either side of the bumper or vertically below the bumper. As the springs and working componentry of this system are exposed on the wall, it is quite easily damaged by trucks which do not align with the bumpers. This results in the need to repair or replace the entire bumper system.

Another spring system has a T-shaped rail attached to the wall of the dock. This rail slidingly receives a bumper having a corresponding T-shaped metal casing embedded therein. The springs of this system are positioned either side of the rail, but again are located externally on the dock wall making them prone to damage. Furthermore, this type of bumper is quite specific and does not allow for the use of other types of rubber bumpers to be used.

Another type of bumper system has a rubber bumper attached to a backing plate, which is secured to the dock wall. A metal casing is secured to the backing plate so as to encapsulate the rubber bumper whilst still allowing the casing to move with respect to the backing plate. However, as the casing is metal it is prone to being dented when trucks engage the bumper. It also causes damage to the trucks when the trucks move up and down relative to the dock.

A further disadvantage with current systems is their width. The degree a bumper apparatus can protrude from the dock is somewhat limited - if it's too large, an unacceptable gap will be formed between the truck and the dock. Therefore, if the design of the bumper system is too thick, the thickness of the rubber bumper needs to be reduced such that the bumper apparatus conforms to these constraints. With these systems, the reduction in the thickness of the rubber obviously provides less cushioning when a truck engages the bumper system, in addition to requiring regular replacement of the rubber bumper as it wears more quickly.

The preceding discussion to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgement or an admission that any of the material referred to was or is part of the common general knowledge as at the priority date of the application.

It is an object of this invention to provide to ameliorate, mitigate or overcome, at least one disadvantage of the prior art, or which will at least provide the public with a practical choice.

Disclosure of the Invention

The present invention provides a sliding apparatus for use on loading docks, the apparatus comprises:

a backing member adapted to be secured to a wall of the dock;

a mounting member slidingly retained on the backing member and adapted to have a bumper secured thereto;

a biasing means to bias the mounting member to a predetermined position relative to the backing member;

wherein the biasing means is encapsulated within the apparatus such that it is not exposed, or susceptible to damage from a vehicle approaching the apparatus.

In contrast to the prior art, the present invention houses all componentry internally such that it is protected and cannot be damaged when trucks either fail to align properly with the bumpers, either vertically or horizontally, or engage the sliding apparatus with excessive force.

Preferably the biasing means is encapsulated between the backing member and the mounting member.

- A -

In one aspect of the invention the biasing means is in the form of at least one spring received between the mounting member and backing member.

Preferably there are two springs.

Each spring may be contained within a void defined by the backing member and mounting member when assembled together. Preferably at least one recess in the mounting member cooperates with at least one recess in the backing member to define the void. Each recess may be substantially parallel with the longitudinal axis of the apparatus.

Preferably each recess extends along a portion of the respective backing member and mounting member. Each recess may have an end wall at at least one end but preferably both ends.

Preferably the backing member and the mounting member each have two recesses to define two voids. Preferably each void is located on opposed sides of the longitudinal axis.

Preferably the mounting member is adapted to slide along the longitudinal axis of the apparatus with respect to the backing member. When the apparatus is used on a dock, the longitudinal axis of the apparatus is preferably orientated substantially vertical. It is to be understood, however, that the longitudinal axis may be any other axis of the backing member without moving away from the spirit of this invention.

The mounting member may comprise a first plate secured to a second plate. The first plate may be secured to the second plate using fasteners.

Preferably the second plate is wider than the first plate such that a portion of the second plate extends beyond an edge of the first plate. Preferably the portion of the second plate extends beyond each side of the first plate.

Preferably an outer face of the first plate supports the bumper.

When the first plate and second plate are assembled, the first plate and second plate may incorporate the at least one recess.

The at least one recess may be defined by at least one slot in the second plate.

The at least one slot in the second plate may incorporate a retaining means for retaining the biasing means relative to the mounting member. The retaining means may comprise a projection extending from an end wall of the at least one slot.

The at least one recess may also be defined by at least one slot in the first plate.

The backing member may comprise a third plate secured to a fourth plate. The third plate may be secured to the fourth plate using fasteners.

Preferably the third plate is wider than the fourth plate such that a portion of the third plate extends beyond an edge of the fourth plate. Preferably the portion of the third plate extends beyond each side of the fourth plate.

When the third plate and fourth plate are assembled, the third plate and fourth plate may incorporate the at least one recess of the backing member.

The at least one recess may be defined by at least one slot in the third plate.

The at least one slot may incorporate a retaining means for retaining the biasing means relative to the mounting member. The retaining means may comprise a projection extending from an end wall of the at least one slot. The at least one recess of the backing member may also be defined by at least one slot in the fourth plate.

The backing member may also comprise a fifth plate which is secured to the dock wall. The fifth plate provides a flat surface positioned at a desired orientation. The fifth plate may be positioned between the dock wall and the fourth plate when the fourth plate is secured to the dock wall.

Preferably an inner face of the fourth plate engages the fifth plate.

The flat surface of the fifth plate allows the fourth plate to engage the fifth plate such that a substantial amount of the force exerted upon the sliding apparatus is transferred to the dock wall. This also assists in preventing the warping of the respective plates.

When the sliding apparatus is assembled, the third plate of the backing member and second plate of the mounting member are retained to one another in sliding engagement.

When assembled the projection incorporated in the at least one sot in the second plate may cooperate with the projection incorporated in the at least one slot in the third plate such that when the at least one recess in the backing member and the mounting member are aligned the projections provide a spike, wherein each spring of the biasing means may be received in each void such that each end of each spring is received over a respective spike in each end of each void. However, when the mounting member moves relative to the backing member the end of the spring may only be supported on the projection provided by the mounting member at one end and the backing member at its other end. This configuration determines the upper and lower limits of the movement of the mounting member relative to the backing member. At both limits the at least one spring will be fully contracted.

Each spike may be adapted to receive one or more spacers such that the tension of the spring may be adjusted accordingly. This will also vary the degree of movement the mounting member has relative to the backing member.

The mounting member and backing member may be held in sliding engagement by a guide means.

The guide means may be in the form of an at least one U-shaped member having a flat base. The at least one U-shape member may define a channel.

A leg portion of the at least one U-shape member may be secured to the side of the second or third plate.

Preferably the at least one U-shape member is secured to the second plate. This will ensure that the apparatus will remain free to slide even if the rubber bumper is in contact with the channel, as the U shaped member is fixed relative to the bumper.

Preferably the leg portion is secured to an outer face of the portion of the second plate extending beyond the first plate.

When the sliding apparatus is assembled the channel may receive those portions of the second plate and third plate extending beyond the first plate and fourth plate respectively.

Preferably the thickness of the channel wall is smaller than the thickness of the fourth plate. This will allow the channel to move relative to the backing member without engaging the fifth plate.

Preferably the thickness of the channel wall is smaller than the thickness of the first plate.

Preferably there are two guide means located on opposed sides of the longitudinal axis of the sliding apparatus.

When the sliding apparatus is assembled, the guide means allow the second plate to slide relative to the third plate whilst retaining the plates together. Having guide means on opposed sides of the second plate and third plate ensures the plates only slide in a direction parallel to the longitudinal axis of the guide means.

The bumper secured to the mounting member may be made from elastomeric material.

In another aspect of the invention the biasing means is provided by at least one gas strut.

As each plate engages the adjacent plate along a large portion of its length there is a substantially solid block of material extending between the rubber bumper and the dock. There is therefore very little likelihood that the void defined between the mounting member and backing member will be compromised by engaging vehicles and hence damage the encapsulated spring.

The configuration of the present invention ensures the biasing means is not damaged if the truck engages the sliding apparatus under normal conditions, or has misaligned with the bumper.

The present invention further provides a sliding apparatus for attaching a bumper to a loading dock, the apparatus comprises

a backing member adapted to be secured to a wall and to slidingly retain a mounting member, such that when assembled the mounting member is able to move only along an axis of the backing member; and

a biasing means to bias the mounting member to a predetermined position relative to the backing member, the biasing means being encapsulated between the backing member and mounting member.

The mounting member may move in a direction along the longitudinal axis of the backing member.

The backing member may have a back face which engages the wall when secured thereto.

In one aspect of the invention the backing member may incorporate at least one channel, preferably the channel may be closed at one end but preferably at both ends.

The backing member may have a portion extending outwardly in the transverse direction. The portion may extend outwardly from the side of the backing member.

The mounting member may have an outer face adapted to have a bumper secured thereto.

Preferably the mounting member has at least one channel, which when assembled cooperates with the at least one channel in the backing member to define at least one void for housing the biasing means.

The mounting member may have a portion extending outwardly in the transverse direction. The portion may extend outwardly from the side of the mounting member.

The biasing means maybe in the form of a spring which is received in the at least one void.

Each channel may comprise a projection in each end thereof. When the sliding apparatus is assembled, each projection in each channel may cooperate with the projection in the corresponding channel to define a spike. Each spike may be received in an end of the spring when the sliding apparatus is in the normal condition.

A guide means retains the mounting member in sliding engagement with the backing member. The guide means comprises a retaining member secured to the portion of the mounting member extending outwardly in a transverse direction.

The extending portion of the backing member may be received in the retaining member such that it may slide relative thereto so that when assembled the mounting member is restricted to move only along an axis of the backing member.

In another aspect of the invention a front face of the backing member may provide at least one channel.

The backing member may also comprise at least one projection projecting from the front face. The at least one projection may extend along the length of the

backing member and be orientated such that the at least one projection is substantially parallel to the at least one channel.

Preferably the at least one projection of the backing member provides an inner sidewall of the at least one channel.

Preferably the at least one channel of the backing member is in the form of a first and second channel extending along the length of the backing member.

The mounting member may have an outer face adapted to have a bumper secured thereto. Preferably an inner face of the mounting member provides at least one channel, adapted to be received in the at least one channel of the backing member so as to define a void when the backing member and mounting member are assembled.

The mounting member may also comprise at least one projection projecting from the inner face. The at least one projection may extend along the length of the mounting member such that the at least one projection is substantially parallel to the at least one channel.

The at least one projection of the backing member is adapted to cooperate with the at least one projection of the mounting member such that when assembled the mounting member is retained and can move only along the longitudinal axis of the backing member.

Preferably the at least one channel of the mounting member is in the form of a third and fourth channel extending along a portion of the mounting member.

The third and fourth channel may extend from a first end of the mounting member and terminate a predetermined distance therefrom.

The biasing means may comprise at least one spring having one end attached to the first end of the mounting member.

Preferably when assembled, the channels of the mounting member and the backing member cooperate to define a first and second void.

Preferably the sidewalls of each channel minimise the risk of the mounting member being forced towards the backing member and hence deform the voids.

Preferably the at least one spring of the biasing means comprises a first and second spring. Preferably when assembled the first spring is housed in the first void whilst the second spring is housed in the second void.

The first and second channel of the mounting member may be closed at the first end of the mounting member.

The first and second channel of the backing member may be closed at a second end of the backing member. Preferably when the sliding apparatus is assembled and in a normal condition, the first and second voids are closed.

Preferably a first end of each spring is attached to the respective closed end of the third and fourth channels of the mounting member.

Preferably the second end of the spring engages the closed end of the first and second channels of the backing member.

Preferably at least one of the channels of the backing member has a projection extending inwardly adjacent the second end thereof. The projection may be adapted to engage a sidewall of one of the channels of the mounting member so as to define maximum expanded condition of the mounting member relative to the backing member. The maximum contracted condition of the apparatus may be defined when the spring is fully compressed.

Each spring may be mounted on spikes which may also receive spacers, allowing the tension of each spring to be easily adjusted with the inclusion of one or more spacers on the spikes.

Obviously the configuration of the mounting member and backing member can be reversed, whilst still remaining within the spirit of this invention.

The present invention further provides a sliding apparatus for attaching a bumper to a loading dock, the apparatus comprises a mounting member slidingly retained on a backing member and adapted to have a bumper secured thereto whilst the backing member is adapted to be secured to the dock, the backing member and mounting member cooperate to define at least one void, the at least one void being adapted to house at least one biasing means, whereby the biasing means is encapsulated between the mounting member and backing member and ensures the return of the mounting member to a predetermined position relative to the backing member.

Preferably the integrity of the at least one void is not compromised when a force in the direction towards the backing member is place on the mounting member.

As the present invention is not reliant on gravity and is self centering, the sliding apparatus works equally well in any orientation including vertically and horizontally, and may also be mounted upside down.

Brief Description of the Drawings

The invention will be better understood by reference to the following description of a two specific embodiments thereof as shown in the accompanying drawings in which:

Figure 1 is a schematic cross sectional view of a sliding apparatus secured to a dock wall according to a first embodiment of the invention;

Figure 2 is a front view of a first plate of a mounting member of the sliding apparatus;

Figure 3. is a front view of a second plate of the mounting member of the sliding apparatus;

Figure 4 is a front view of a third plate of a backing member of the sliding apparatus;

Figure 5 is a front view of a fourth plate of the backing member of the sliding apparatus;

Figure 6 is a front view of a fifth plate of the backing member of the sliding apparatus;

Figure 7 is an exploded end view of the sliding apparatus;

Figure 8 is a front view of a backing member of a sliding apparatus according to a second embodiment of the invention;

Figure 9 is a front view of a mounting member of the sliding apparatus; and

Figure 10 is a cross sectional view of the sliding apparatus without the springs shown.

Best Mode(s) for Carrying Out the Invention

The invention relates to a sliding apparatus 111 for use on loading docks. The sliding apparatus 111 , according to a first embodiment comprises a backing member 115, a mounting member 117 and a biasing means 119.

The biasing means 119 comprises two springs (not shown) and is discussed in further detail below.

Referring to figure 1 and 7, the mounting member 117 comprises a first plate 121 secured to a second plate 123 using fasteners 125. The second plate 123 is wider than the first plate 121 such that a portion 127 of the second plate 123 extends beyond both sides 129 of the first plate 121.

Preferably an outer face 131 of the first plate 121 engages a rubber bumper 133. The bumper 133 is secured to the mounting member 117 by bolts 141a which

pass through apertures 143a in the first plate 121 and second plate 123. These apertures may vary in size.

When the first plate 121 and second plate 123 are assembled, the first plate 121 and second plate 123 incorporate two recesses 135a, each closed at both ends. The recesses 135a are in opposed relation with respect to the longitudinal axis of the sliding apparatus 111 , with each recess 135a being substantially parallel thereto.

Each recess 135a is defined by the cooperation of a slot 137a in the second plate 123 as shown in figure 3, and a slot 139a in the first plate 121 as shown in figure 2.

Each slot 137a in the second plate 123 incorporates a retaining means in the form of a projection 145a at each end of the slot 137a which is designed to retain the biasing means relative to the mounting member 117.

Referring to figure 1 the backing member 115 comprises a third plate 151 secured to a fourth plate 153 using fasteners 125. The third plate 151 is wider than the fourth plate 153 such that a portion 152 of the third plate 151 extends beyond both sides 154 of the fourth plate 153.

The backing member 115 also comprises a fifth plate 155 which is fixed to the dock wall 112 and which engages the fourth plate 153. It is important that the fifth plate 155 provides a flat surface to which the fourth plate 153 engages. This will ensure maximum contact between the plates allowing as much force as possible to be transferred to the dock wall 112, which also assists in preventing the plates from warping when vehicles engage the sliding apparatus 111.

To assist in obtaining good securement of the fifth plate 155 to the dock wall 112 the fifth plate has a plurality of apertures 156 therein to allow air pockets to be expelled from between the fifth plate 155 and the dock wall 112 when being fitted.

The backing member 115 is secured to the dock wall 112 by bolts 141 b which pass through apertures 143b in the third plate 151 , the fourth plate 153 and fifth plate 155. These apertures may vary in size.

When the fourth plate 153 and third plate 151 are assembled, the fourth plate 153 and third plate 151 incorporate two recesses 135b, each closed at both ends. The recesses 135b are in opposed relation with respect to the longitudinal axis of the sliding apparatus 111 , with each recess 135b being substantially parallel thereto.

Each recess 135b is defined by the cooperation of a slot 137b in the third plate 151 as shown in figure 4, and a slot 139b in the fourth plate 153 as shown in figure 5.

Each slot 137b in the third plate 151 incorporates a retaining means in the form of a projection 145b at each end of the slot 137b which is designed to retain the biasing means relative to the backing member 115.

When the sliding apparatus 111 is assembled each recess 135a of the mounting member 117 cooperates with the respective recess 135b of the backing member 115 to define a void 157. The projections 145a, 145b in each slot 137a, 137b also cooperate such that when the backing member 115 and mounting member 117 are aligned, the projections 145a, 145b define a spike 146 at each end of each void 157.

Each void 157 receives a spring therein whereby the ends of each spring receive a respective spike 146 so that the spring is retained thereover.

The mounting member 117 is retained in sliding engagement with the backing member 115 by a guide means 159. The guide means 159 comprises two u- shaped members 161 , each secured to an outer face 128 of the portions 127 of the second plate 123 using fasteners 125, with the two U-shaped members 161 being located on opposite sides of the sliding apparatus 111. As shown in figure 7, each U shaped member 161 comprises a flat base and two leg portions 163 to

define a channel 165.

As shown in figure 1 , the width of the leg portions 163 is less than the width of the first plate 121 and, more importantly, the fourth plate 154. This ensures that as the mounting member 117 moves relative to the backing member 115 the U- shaped member 161 does not scrape along the fifth plate 155.

When assembled, the portions 127 of the second plate 123 and the portions 152 of the third plate 151 are received in the channel 165 so as to be slidingly retained with respect to the U-shaped member 161.

In use, the mounting member 117 is slidingly retained to the backing member 115 such that a contact face 167a of the second plate 127 slides over a contact face 167b of the third plate 151. To assist in movement between the two contact faces a lubricant can be used. If required, the lubricant can be injected through grease nipples (not shown).

Each spring is received in the respective void 157 to encapsulate the spring therein. This ensures each spring is not susceptible to damage by a truck which may misalign with the rubber bumper on the sliding apparatus 111.

When the sliding apparatus 111 is assembled the mounting member 117 is slidingly retained on the backing member 115 such that the movement of the mounting member 117 is limited to slide along the longitudinal axis of the sliding apparatus 111. The movement of the mounting member 117 relative to the backing member 115 is limited to those positions where each spring is fully compressed at one end of the recess 135b in the backing member 115, and fully compressed at the other end of the recess 135b.

As the sliding apparatus 111 comprises substantially of flat plates stacked one on the other the apparatus 111 has sufficient strength such that if a truck where to engage the apparatus with excessive force, the mounting member 117 would not be forced towards the backing member 115 and hence compromise the integrity of the voids 157.

When a vehicle (not shown) is at a dock and in engagement with the rubber bumper on the sliding apparatus 111 any vertical movement of the truck causes the mounting member 117 to slide along the backing member 115 in the corresponding direction, thus reducing any wear experienced by the rubber bumper.

The invention according to a second embodiment is shown in figures 8 to 10. In this embodiment a sliding apparatus 11 comprises a backing member in the form of a backing plate 15, a mounting member in the form of a mounting plate 17 and a biasing means 19.

Referring to figure 8, the backing plate 15 comprises a flat plate 21 having a first end 37, a second end 22, a back face 23 and a front face 24.

The front face 24 of the backing plate 15 comprises a first channel 25 and a second channel 27. Each channel 25, 27 is orientated substantially parallel to the longitudinal axis of the backing plate 15. The channels 25, 27 extend along the length of the flat plate 21 and are located either side of the longitudinal axis. Each channel 25, 27 is defined by a sidewall 29 and a projection in the form of a rail 31. The rail 31 provides the innermost wall of each channel 25, 27.

Each channel 25, 27 is closed at the end adjacent the second end 22 of the flat plate 21 by a closure 35.

The sidewall 29 of each channel 25, 27 adjacent the first end 37 of the flat plate 21 incorporates an inwardly projecting screw 39 for reasons which will be discussed below.

The back face 23 of the flat plate 21 engages the dock when the backing plate 15 is secured thereto. The backing plate 15 also comprises a plurality of apertures 33, which receive bolts (not shown) to secure the backing plate 15 to the dock.

Referring to figure 9, the mounting plate 17 comprises a flat plate 41 having a first end 42, an inner face 43 and an outer face 44.

The inner face 43 of the mounting plate 17 comprises a third channel 45 and a fourth channel 47. Each channel 45, 47 is located either side of the longitudinal axis of the mounting plate 15 in opposed parallel relation. Each channel 45, 47 is defined by a pair of projections 49 which extend along a portion of the flat plate 41 from the first end 42. The outermost projection 49a of each pair of projections 49 has an outwardly extending tab 53 protruding at the remote end from the first end 42 of the flat plate 41 for reasons which will be discussed below.

Each channel 45, 47 is closed at the end adjacent the first end 42 of the flat plate 41 by closures 55.

Each closure 55 has an inwardly projecting spike 57 for reasons which will be discussed below.

Each channel 45, 47 is adapted to be snugly received in respective channels 25, 27 of the backing plate 15 such that the channels 45, 47 may slide relative to channels 25, 27. When received therein the channels 45, 47 of the mounting plate 17 cooperate with the channels 25, 27 of the backing plate 15 to define a first void 71 and a second void 73.

The inner face 43 also has two further projections extending upwardly therefrom in the form of a rail 51. Each rail 51 is orientated on either side and substantially parallel to the longitudinal axis of the mounting plate 17. Each rail 51 is located between the longitudinal axis and respective channel 45, 47.

As shown in figure 10, each rail 51 of the mounting plate 17 is adapted to slidingly engage the respective rail 31 of the backing plate 15.

The outer face 44 of the flat plate 41 of the mounting plate 17 is adapted to have a rubber bumper (not shown) secured thereto. The mounting plate 17 has a plurality of apertures 63 which receive bolts (not shown) to secure the rubber bumper to the mounting plate 17.

Not shown in the figures is the biasing means 19. The biasing means 19

comprisΘS a first spring 91 and a second spring 93. Each spring 91 , 93 is received in the respective void 71 , 73 such that the respective spring 91 , 93 is encapsulated therein. This ensures each spring 91 , 93 is not susceptible to damage by a truck which may misalign with the rubber bumper on the sliding apparatus 11.

Each spring 91 , 93 has a first end 95, adapted to be received over the spike 57. A second end 97 of each spring 91 , 93 is adapted to engage the respective closure 35 of the backing plate 15.

If the tension of the springs 91 , 93 needs to be adjusted a spacer may be placed on the relevant spike 57 to vary the tension of the spring 91 , 93.

When the sliding apparatus 11 is assembled the mounting plate 17 is slidingly retained on the backing plate 15 such that the movement of the mounting plate 17 is limited to slide along the vertical axis of the sliding apparatus 11. This is ensured by the cooperation of the rails 31 of the backing plate 15 with the rails 51 of the mounting plate, as shown in figure 8. The cooperation of the rails 31 , 51 locks the mounting plate 17 to the backing plate 15 such that it is retained thereto. There are many different ways the rails can be configured so as to be locked together whilst still allowing the rails to slide with respect to each other. It is to be understood that these variations are considered to fall within the scope of this invention.

The configuration of the apparatus 11 limits the sliding movement between an extended position and a contracted position which is discussed below. The configuration of the channels and projections of each plate ensures the apparatus 11 has sufficient strength such that if a truck where to engage the apparatus with excessive force, the mounting plate 17 would not be forced towards the backing plate 15 and hence would not compromise the integrity of the voids 71 , 73.

When a vehicle (not shown) is at a dock and in engagement with the rubber bumper on the sliding apparatus 11 any vertical movement of the truck causes the mounting plate 17 to slide along the backing plate 15 in the corresponding

direction, thus reducing any wear which would otherwise be experienced by a fixed rubber bumper.

As mentioned above, the sliding apparatus 11 has expanded and contracted limits. The expanded condition of the sliding apparatus 11 is reached when the tabs 53 on the channels 45, 47 of the mounting plate 17 engage the inwardly projecting screws 39 on the sidewalls 29 of the channels 25, 27 of the backing plate 15. The contracted condition is reached when the biasing means 19 is fully compressed. The compact size of the sliding apparatus also allows a considerably thick rubber bumper to be secured thereto. This adds cushioning when the vehicle engages the sliding apparatus.

The configuration of the sliding apparatus 11 , 111 is not restricted to a particular type of rubber bumper but allows numerous types of rubber bumpers to be secured thereto.

Modifications and variations such as that would be apparent skilled addressee are considered to fall within the scope of the present invention.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.