GB2324993A - A connection between frames of a pallet retention unit - Google Patents

Abstract

A pallet retention unit comprises a plurality of pivotably linked frames enclosing a pallet, a releasable connection between two linked frames 14 and 28 being formed by a captive pin 34 on the first frame 28 displaceable into a female element 16 on the second frame 14. The captive pin 34 has only limited movement, being slidable within a fixed sleeve 32 on the first frame 28 but constrained in this movement by a stop means 40 on the first frame 28 and the fixed sleeve 32. Preferably the stop means 40 is formed from a flange projecting from the top horizontal strut 26 of the first frame 28. The first frame 28 may be provided with a lower female element 30 and an upper coaxial pin 34, the second frame 14 then being provided with an upper female element 16 and a lower coaxial pin 20, at least on of the pins 20 and 34 being of the slidable, captive type claimed.

Description

PALLET RETENTION UNITS This invention relates to pallet retention units.

Pallet retention units are used in conjunction with pallets to prevent goods stacked on a pallet from falling off the pallet, and consist essentially of four linked frames which define a square or rectangular enclosure at the bottom of which is positioned the pallet.

Various methods have been used for connecting the frames together. In one known method, at each corner of the unit, a vertical hollow strut of one frame is provided with a vertical slot in one wall and a vertical strut of the adjacent frame is provided with a projecting flange having a hooked end. The said adjacent frame is raised to a height above that of the said one frame and is then lowered so that the flange is arranged to slide down the slot with the hooked end preventing separation of the frames. However, the assembly and dismantling of the frames requires the services of several persons. Also, because of the environment in which such pallets are used, e.g. with fork-lift trucks, the frames can become damaged and distorted, thereby making it difficult or even impossible to assembly two frames together or to separate them once assembled.

In another known method, at each corner of the unit, a vertical strut of one frame is provided with upper and lower downwardly projecting pins and a vertical strut of the adjacent frame is provided with a corresponding pair of hollow sleeves. By a lifting and lowering movement the pins are dropped into the sleeves and one then has a double pivot linkage connecting the two frames. However, such a linkage can become detached if for example the pallet is not evenly loaded and is then picked up by a truck, or under other circumstances where there are unsymmetrical forces. This then represents a hazard to persons in the vicinity of the unit.

In yet another known method, at each corner of the unit, a vertical strut of one frame and a vertical strut of the adjacent frame are each provided with external hollow sleeves and an elongate pin extending substantially the height of the frames is pushed down through the respective sleeves to serve as a hinge pin. A disadvantage of this arrangement is that the pins, being separate components, can become lost or are not returned with the units after dismantling. Also, because of the length of the pins, they can become bent, thus preventing them from being fitted into the sleeves or else causing them to become jammed within the sleeves and making dismantling of the unit difficult.

It is an object of the present invention to provide a pallet retention unit which can easily, quickly and reliably be assembled and dismantled.

It is another object of the invention to provide a pallet retention unit which is safe in use, with the frames once assembled being almost impossible to become detached accidentally.

In accordance with the invention there is provided a pallet retention unit comprising a plurality of frames arranged to be linked to form an enclosure around a pallet, wherein at least some of the frames are connectable by interengageable male and female elements on the respective frames to establish pivot connections between the frames, and wherein in the connection of each such connectable frame to an adjacent such connectable frame there is included a captive male element on one frame displaceable into a female element on the other frame.

Preferably, at each coupling of two such connectable frames each of the frames is provided with one male element and one female element, said captive male element being one of said elements.

Preferably, the captive male element comprises a pin slidable within a fixed sleeve and having its displacement limited in one direction by stop means on its associated frame and in the other direction by the fixed sleeve.

In order that the invention may be fully understood, a presently preferred embodiment of pallet retention unit will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a partial front view of one side frame of the unit; Fig. 2, is a partial end view of the side frame of Fig.

1, in the direction of the arrow A in Fig. 1; Fig. 3 is a partial front view of the rear frame of the unit; Fig.4 is a partial end view of the rear frame of Fig. 3; Fig. 5 is a partial view illustrating the assembly of the side frame to the rear frame; Fig. 6 is a partial view illustrating the position of the linkage members when the side frame and rear frame are assembled; Figs. 7A and 7B show two alternative designs of locking pin; and, Fig. 8 is a schematic diagram illustrating an alternative pin stop.

A pallet retention unit comprises four frames set around a pallet to form an enclosure for goods stacked on the pallet.

These frames will hereinafter be referred to as a front frame, a rear frame and two side frames. Each frame comprises a horizontal top strut, a horizontal bottom strut and two vertical end struts, making a square or rectangular frame.

Within the strut framework one can provide an array of cross struts or other bracing means, or a mesh cover for example, both to strengthen the frames and to prevent stacked goods from falling. The components of the frames are welded together.

Figs. 1 and 2 show the connecting linkage which is provided at the end of each side frame. The top strut of the side frame is indicated at 10, the bottom strut at 12, and one of the end struts at 14. The struts may be hollow tubes or any other suitable section. The end strut 14 is provided with two vertically spaced linkage components on its outwardly facing surface. The upper one is a tubular sleeve 16 which is welded, as indicated at 18, to the strut 14. The lower one is a downwardly projecting solid cylindrical pin 20 which is welded via a fillet 22 to the strut 14. The sleeve 16 and pin 20 are aligned on a common vertical axis 24.

Figs. 3 and 4 show the connecting linkage which is provided at the ends of the rear frame and of the front frame and which links with the ends of the side frames. The top strut of the rear frame is indicated at 26 and is here shown as a metal section of generally L-shape. This facilitates stacking of pallet units one on top of another. One vertical end strut is shown at 28, and is a hollow section tube. The end strut 28 is also provided with two vertically spaced linkage components, on its forwardly facing surface. The lower one is a hollow tubular sleeve 30 welded to the strut.

The upper one comprises a similar hollow tubular sleeve 32 and also a pin 34. It is an essential feature of the invention that the pin 34 is a captive element, captive in the sleeve 32. The pin 34 has a solid stem 36 which is slidable within the sleeve 32 and an enlarged head 38 which cannot pass through the sleeve. Also, the horizontal flange 40 of the top strut 26 projects beyond the end strut 28 to form a stop or abutment for the head of the pin. When the pin 34 is fully raised, the head 38 contacts the flange 40 but the stem 36 is still within the sleeve 32. When the pin is fully lowered the head 38 rests on the top of the sleeve 32. The pin is therefore captive in all settings, and is not removable from the frame. To fit the pin 34 to the frame it is inserted into the sleeve and the pin/sleeve combination is then welded in place on the strut 28. The pin 34, upper sleeve 32 and lower sleeve 30 are all aligned on a common vertical axis 42.

Figs. 5 and 6 illustrate how the frames are linked together, using as an example one side frame and the rear frame. Equivalent connections are made at each of the other corners of the pallet retention unit. As illustrated, the side frame is offered up to the rear frame (Fig. 5), with the side frame pin 20 being fitted into the lower sleeve 30 of the rear frame. The rear frame pin 34 is manually held raised so that the bottom end of the pin is retracted within the sleeve 32, so that the sleeve 16 of the side frame can locate just below the upper sleeve 32 of the rear frame. When the side frame 14 is in position the captive pin 34 is released, drops into the side frame sleeve 16, and creates the double pivot linkage illustrated in Fig. 6. To dismantle the frames, one simply raises the captive pin and lifts one frame from the other.

It will be appreciated that a key factor is the length of the pin 34 in relation to the distance between the underside of the stop flange 40 and the top of the upper sleeve 32. The pin/sleeve combination 34,32 must be welded in place so that the pin 34 is thereafter always captive.

The shape of the captive element which performs the locking function can take any one of many forms. Two alternative examples are shown in Figs. 7A and 7B at 34a and 34b. Also, the stop or abutment which limits movement of the captive pin need not be a flange on the top strut, but could be a separate stop member welded to the frame, such as is shown at 44 in Fig. 8. Other alternatives are possible.

Although in this illustrated embodiment the frames are provided each with one male and one female linkage element at each end, other alternative configurations are possible within the scope of the invention. For example, at each corner, both male elements could be provided on one frame and the two female elements on the adjacent frame.

Although with a four-frame pallet retention unit it is desirable that a linkage mechanism according to the invention is used at each of the four corners, for convenience and safety, it would be possible to connect the rear frame and side frames together in this manner and to have the front frame attachable and detachable in an alternative way.

Claims (6)

CLAIMS:

1. A pallet retention unit comprising a plurality of frames arranged to be linked to form an enclosure around a pallet, wherein at least some of the frames are connectable by interengageable male and female elements on the respective frames to establish pivot connections between the frames, and wherein in the connection of each such connectable frame to an adjacent such connectable frame there is included a captive male element on one frame displaceable into a female element on the other frame.

2. A pallet retention unit as claimed in claim 1, in which at each coupling of two such connectable frames each of the frames is provided with one male element and one female element, said captive male element being one of said elements.

3. A pallet retention unit as claimed in claim 2, in which one of the frames is provided with an upper female element and a coaxial lower male element, and the other frame is provided with a lower female element and a coaxial upper captive male element.

4. A pallet retention unit as claimed in any preceding claim, in which the captive male element comprises a pin slidable within a fixed sleeve and having its displacement limited in one direction by stop means on its associated frame and in the other direction by the fixed sleeve.

5. A pallet retention unit as claimed in claim 4, in which the stop means is a projecting flange from a horizontal top strut of the frame.

6. A pallet retention unit substantially as hereinbefore described with reference to the accompanying drawings.