GB2135959A - Improved tailgate safety fence - Google Patents

Abstract

A tailgate loader having a load retention fence which comprises; a pair of elongated arms (30) pivotally mounted on a platform (16) at a side edge thereof. The arms are movable relative to said platform between a storage position in which they are upright and extend substantially parallel to the platform when the platform is in its storage position and a deployed position in which they extend upwardly and rearwardly from the inner end of the platform when the platform is in its deployed position. Flexible side fence chains (32) connect the distal end of each arm (30) to an adjacent slide member (12). Tie chains (34) connect the distal end (40) of each arm (30) and the outer end of the platform, and have a length so as to be taut when the platform is in its deployed position. The tie chains (34) serve to deploy said arms automatically in response to movement of said platform between its storage position and its deployed position. An outer fence (36) is detachably mountable at the distal ends of the arms (30). <IMAGE>

Description

SPECIFICATION Improved tailgate safety fence This invention relates to tailgate lift platform mechanisms for trucks and the like.

In particular, this invention relates to an improved retention fence for a tailgate lift platform.

A retention fence for a tailgate lift platform is described in United States Patent No. 4,198,188 dated April 15, 1980 issued to William V. Perkins. In this mechanism, the retaining fence is in the form of a pair of rigid arms which are pivotally connected to the slides on which the platform is pivoted at a substantial distance above the platform. The arms pivot between an upright position and a horizontal position in response to movement of the platform between its upright position and its horizontal position. When in the upright position, the arms project above the outer end of the platform and in many applications these arms may project above the body of the truck to which the platform is attached.

There are many installations where restricted head room is available for trucks backing in to loading docks and the side fences of this prior patent can extend to a height above the body of the truck so as to form an obstruction preventing backing up to a loading dock.

Parallelogram linkage mechanisms are notoriously difficult to maintain in good working order in environments where they are subjected to impact loading and consequently, considerable difficulty would be experienced in attempting to maintain the parallelogram linkage mechanism used for deploying the platform and retaining arms of Perkins.

It is an object of the present invention to provide a simple and inexpensive retention fence mechanism which can be stored in a compact configuration in close proximity to the platform when it is in its storage position.

It is a further object of the present invention to provide a simple and inexpensive retention fence in which the deployment mechanism includes flexible side fences and flexible ties connected to the distal end rigid arms which are pivotally connected to the platform adjacent the inner end of the platform.

According to one aspect of the present invention, there is provided in a tailgate laoder of a truck or the like, having a load elevator mechanism which comprises a loading platform which has an inner end and an outer end and a pair of oppositely disposed side edges and wherein the platform is pivotally mounted at its inner end on a pair of slide members for movement about a first axis between an upright storage position and a generally horizontal deployed position, said slide members being movable relative to the truck to raise and lower the platform as required in use, the improvement of a load retention fence comprises; a pair of elongated arms each having a proximal end and a distal end, the proximal end of each arm being pivotally mounted on said platform at a side edge thereof at a point adjacent said inner end of said platform, said arms being movable relative to said platform between a storage position in which they are upright and extend substantially parallel to the platform when the platform is in its storage position and a deployed position in which they extend upwardly and rear wardlyfrom the inner end of the platform when the platform is in its deployed position, said arms having a sufficient length to locate the distal ends thereof, a substantial distance above the platform and over iying the outer portion of the platform when in said deployed position, flexible side fence means connecting the distal end of each arm to an adjacent slide member so as to prevent rotation of each arm relative to the platform beyond that required for movement between said storage position and said deployed position of said arms, said side fence means being connected to said slide members at a height above the pivotal connection of the platform to the slide members so as to extend substantially horizontally when the arms are deployed to form a load restraining side fence at each side of the platform, flexible tie means connecting the distal end of each arm and the outer end of said platform, said flexible tie means having a length so as to be taughtwhen said platform is in its deployed position and said arms are in their deployed position, said flexible tie means serving to automatically deploy said arms in response to movement of said platform between its storage position and its deployed position, outer fence means detachably mountable at the distal ends of said arms to extend transversely therebetween when said arms are deployed so as to form a load retaining fence at a substantial distance above the outer end of the platform when the platform is in its deployed position, said outer fence means being detachable so as to be removable to avoid forming an obstruction when said arms are in their storage position.

The invention will be more clearly understood after reference to the following detailed description read in conjunction with the drawings wherein, Figure lisa pictorial side view of a lift tailgate showing the load retention fence in its deployed position.

Figure 2 is a partial view of the tailgate of Figure 1 showing the platform and load retention fence in their storage position.

Figure 3 is an enlarged detailed view showing the outer fence mounted on the distal ends of the elongated arms.

With reference to Figure 1 of the drawings the reference numeral 10 refers generally to atailgate loader constructed in accordance with an embodiment of the present invention. The tailgate loader is of a conventional type which includes an elevated ride mechanism which is not shown which serves to raise and lower a pair of slide members 12 which are slidably mounted in guide rails 14 which are mounted at the loading end of a truck generally identified by the reference numeral 20. A platform 16 has its inner end pivotally mounted on lugs 18 of the slide members 12 means of pivot pins 22. The platform 16 is movable between the deployed generally horizontal position shown in Figure 1 of the drawings and the upright storage position shown in Figure 2 of the drawings.In moving between the deployed position and the upright position, the platform pivots about the pivot ends 22 in the direction of the arrow B. A pair of brackets 24 project laterally from the opposite side edges of the platform. As shown in Figure 2 of the drawings, the brackets 24 serve as latches which may be releaseably retained by latch plates 26 to retain the platform 16 in its upright storage position. The latch 24 may be positioned in the latch plate 26 or released from the latch plate 26 by causing the slide members 12 to be lowered or raised in the direction of the arrows A of Figure 1 when in the upright configuration.

The load retention fence comprises a pair of rigid arms 30, a pair of flexible side fence chains 32, a pair of flexible tie chains 34 and a detachable outer fence rail 36.

The elongated arms 30 each have a proximal end 38 and a distal end 40. The proximal end 38 of each arm is pivotally connected by means of a pivot pin 42 to a side edge of the platform 16 closely adjacent the inner end of the platform 16. A lug 44 projects laterally from the arms 30 and serves to bear against the back edge of the slide members 12 as shown in Figure 2 of the drawings when the arms 30 are in the upright storage position so that the arms 30 are retained in the upright position between the engagement with the slide member 12 and the latch 24.

A bracket 46 (Figure 1 and Figure 3) is located at and projects laterally from the distal end of each arm 30. The bracket 46 has mounting passages 48 and 50 opening therethrough.

The arms 30 are movable relative to the platform between the storage position shown in Figure 2 of the drawings in which they are upright and extend substantially parallel to the platform and the deployed position in which they extend upwardly and rearwardly from the inner end of the platform. The arms have a sufficient length to locate the distal ends thereof a substantial distance above the platform and overlying an outer portion of the platform when in the deployed position. Preferably, the arms will have a sufficient length to ensure that the distal end 40 of each arm is positioned at a height of about 3 to 4 feet above the platform in the deployed position so as to be suitable for supporting unstable loads such as pressurized gas cylinders.

The flexible side fence chains 32 have one end connected to a lug 52 located at the upper end of the slide 12 and their other end located in the mounting passages 48 of the lugs 46 of the arms 30. The chains 32 are in the form of strong metal link chains are proportioned to limit rotation of the arms 30 relative to the platform 16 to that required to deploy the arms 30 and to prevent further rotation beyond the deployed position. The chains 32 are connected to the slide 12 at a height above the platform so as to extend substantially horizontally when the arms are deployed as shown in Figure 1 of the drawings. The weight of the platform is born by the chains 32 with the resu It that the chains are retained in a taut condition and serve as load restraining side fences.

While the chains 32 are retained taut, they are sufficiently flexible that they will yield when subjected to a heavy load and will not become inoperative by reason of deflection under the influence of the load.

The flexible tie members 34 are in the form of metal link chains having one end connected to the distal end of each arm by connection with the mouting passage 50 of the lug 46. The other end of each flexible tie 34 is connected to a lug 54 which projects from the inner face of the latch 24. Thus, it will be seen that the flexible tie chain 34 serves to connect the distal ends of the arms 30 to the platform 16 adjacent the outer edge thereof. The lugs 46 and 54 are arranged such that when the arms 30 are in the deployed position, the flexible tie chains 34 will extend substantially vertically. The chains 34 have a length so as to be taut when the platform is deployed in a generally horizontal plane and the arms are in their deployed position.The chains 34 and 36 serve to automatically deploy the arms 30 in their deployed position when the platform moves from its storage position to its deployed position.

The outer fence member 36 is in the form of a tubular member 60 which has a pair of elbows 62 projecting one from each end thereof. The elbows 62 are proportioned to fit within sleeves 64 which are secured as by welding to the inner faces 66 of the distal ends of the arms 30. A locking pin 68 is removably mounted in a passage 70 formed at the end of one of the elbows 62 so as to provide a sufficient free vertical length of elbow 62 to permit the other elbow 62 to be raised and lowered into and out of engagement with the socket 72 formed in the sleeve 64. This permits the rail 36 to be raised to reiease one of the elbows 62 from its socket so that the fence can be pivoted about its other end in the direction of the arrow C shown in Figure 1 of the drawings.This permits opening and closing of the retaining fence without the need to completely remove the retaining fence.

In use, the platform 16, arms 30 and chains 32 and 34 are stored in the configuration shown in Figure 2 of the drawings with the latch 24 positioned in the latch plate holder 26. If required, the outer fence rail 36 may be completely removed.

In order to deploy the platform and the load retaining fence, it is merely necessary to raise the platform from the position shown in Figure 2 by raising the slides 12. After the latch 24 has been raised out of engagement with the latch plate 26, the platform 16 may be manually engaged to cause itto pivot about its pivotal connection with the slides 12 to move toward the horizontal deployed position shown in Figure 1. Generally the arms 30 will move outwardly with the platform 16 until the chains 32 are drawn taut. Thereafter, the platform 16 will pivot relative to the arms 30 until the chains 34 are taut.

When the chains 32 and 34 are taut, the arms 30 and platforms 16 are automatically retained in their deployed position as shown in Figure 1. The platform may be raised and lowered in the direction of the arrow A when in the deployed position as is conventional practice. When a load is to be unloaded from the body of the truck with the platform in the raised position, the load may be positioned so as to bear against the side fence chains 32 and/orthe outer fence 36. Additional tie members may be provided (not shown) for tying the load members against the side fence chains 32 or the outer fence 36 as required in use. After the platform is lowered to the position shown in Figure 1, the outer fence 36 may be opened as previously described to permit the removal of the load from the platform.It will be apparent that in some circumstances it may be desirable to completely remove the outer fence 36 and this can be done with ease by removing the locking pin 36.

in order to return the platform 16 to the storage position, it is merely necessary to pivot the platform about its pivot pins 22 in the direction of the arrow B (Figure 2). Initially, this action will cause the chains 34 to collapse and thereafter, the brackets 24 will engage the distal ends of the arms 30 so that continued movement will cause both the platform and the arms 30 to move to their upright position. By raising the slides 12 to a position in which the latches 24 are disposed above the notches which are formed in the latch plates 26, it is possible to position the latch 24 in alignment with the notches of the latch plates 26 and thereafter to lower the latches 24 into the latch plates 26.

Various modifications of the present invention will be apparent to those skilled in the art. For example, it will be apparent that the outer fence 36 may be in the form of a flexible chain which is proportioned so as to be substantially taut when extended between the distal ends of the rams 30 in use. In adddition, it will be apparentthat because the arms 30 are pivotally connected to the platform, the arms can be proportioned so as to extend only a short distance above the outer edge of the platform when it is in the storage position. This is of importance in application where the vehicle is to be loaded and unloaded at a loading dock which is of a height substantially equal to the height of the bed of the truck.It will be understood that the platform illustrated in Figure 1 of the drawings can be moved to an upright storage position when the slides 12 are in the lowered position shown in Figure 1 in which case the outer edge of the platform 16 will be located below the back edge of the floor 21 of the truck. Thus, by removing the rail 36, it is possible to load and unload the truck with the back end of the truck closely adjacent the loading dock.

It will also be apparent that when the platform 16 is in the storage position shown in Figure 2 of the drawings, the arms 30 do not extend above the upper edge of the platform 16 to an extent greater than one half of the total height of the platform 16 in the storage position. Thus, it will be seen that the arms 30 do not represent a major obstruction to overhead canopies or doorway headers when a truck is backed up to a loading bay. These and other advantages of the retention fence of the present invention will be apparent to those skilied in the art.

Claims (6)

1. In a tailgate loader of a truck or the like, having a load elevator mechanism which comprises a loading platform which has an inner end and an outer end and a pair of oppositely disposed side edges and wherein the platform is pivotally mounted at its inner end on a pair of slide members for movement about a first axis between an upright storage position and a generally horizontal deployed position, said slide members being movable relative to the truck to raise and lower the platform as required in use, the improvement of a load retention fence comprising;; a) a pair of elongated arms each having a proximal end and a distal end, the proximal end of each arm being pivotally mounted on said platform art a side edge thereof at a point adjacent said inner end of said platform, said arms being movable relative to said platform between a storage position in which they are upright and extend substantially parallel to the platform when the platform is in its storage position and a deployed position in which they extend upwardly and rearwardly from the inner end of the platform when the platform is in its deployed position, said arms having a sufficient length to locate the distal ends thereof, a substantial distance above the platform and overlying an outer portion of the platform when in said deployed position, b) flexible side fence means connecting the distal end of each arm to an adjacent slide member so as to prevent rotation of each arm relative to the platform beyond that required for movement between said storage position and said deployed position of said arms, said side fence means being connected to said slide members at a height above the pivotal connection of the platform to the slide members so as to extend substantially horizontally when the arms are deployed to form a load restraining side fence at each side of the platform, c) flexible tie means connecting the distal end of each arm and the outer end of said platform, said flexible tie means having a length so as to be taut when said platform is in its deployed position and said arms are in their deployed position, said flexible tie means serving to automatically deploy said arms in response to movement of said platform between its storage position and its deployed position, d) outer fence means detachably mountable atthe distal ends of said arms to extend transversely to extend therebetween when said arms are deployed so as to form a load retaining fence at a substantial distance above the outer end of the platform when the platform is in its deployed position, said outer fence means being detachable so as to be removable to avoid forming an obstruction when said arms are in their storage position.

2. Atailgate lift platform as claimed in Claim 1, further comprising stop means on said platform for engaging said arms when the platform moves from its deployed position to its storage position to move said arms from their deployed position to their storage position thereby to automatically move the arms to their storage position as the platform is moved to its storage position.

3. Atailgate lift platform as claimed in Claim 1 or Claim 2, wherein said flexible tie means are each in the form of a metal link chain.

4. A tailgate lift platform as claimed in any preceding claim, wherein each of said flexible side fences are in the form of a metal link chain.

5. Atailgate lift platform as claimed in any preceding claim, wherein said outer fence means has one end adapted to pivot about the distal end of its associated arm whereby the other end of said outer fence means may be swung away from the distal end of the other of said arms.

6. A tailgate lift platform substantially as hereinbefore described, with reference to, and as illustrated in, the accompanying drawings.