Horizontally supported planar surfaces – Industrial platform – Knockdown or setup
Reexamination Certificate
1997-12-12
2003-07-01
Chen, Jose V. (Department: 3637)
Horizontally supported planar surfaces
Industrial platform
Knockdown or setup
C108S051110, C411S283000
Reexamination Certificate
active
06584915
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an improved joint structure formed between components of which one is timber and which are secured by nail fasteners.
BACKGROUND OF THE INVENTION
The invention, to be distinguished in our product range by the designation “Blue Fastening System”, has particular application to pallets, and is illustrated by that application. However, it is to be appreciated that the invention has application in joints other than those in pallets. The invention is concerned with providing a joint which is strengthened against forces acting parallel to a surface of each of the components at a join therebetween i.e. forces which place nails securing the joint in shear.
A well known type of timber pallet is of rectangular form in plan view and has a top, load supporting surface defined by a plurality of laterally extending, load support boards. The boards are secured in assembly by being nailed to laterally spaced side bearers each of which extends at right angles to and below a respective end of each board. Usually there is also an intermediate bearer to which the boards are nailed. The pallet can stand on the bearers but, more usually, a base is secured to the bearers.
In one form of pallet of that known type, herein referred to as “a bearer pallet”, each of the bearers (including an intermediate bearer if provided) is in the form of an elongate beam which may be of substantially uniform cross-section or which may be notched. In such case the base usually comprises a plurality of laterally extending base boards, which may be similar to the support boards and which are nailed to each bearer. In another form of pallet of the known type, herein referred to as a “block pallet”, each of the bearers includes an elongate bearer plate and at least a respective bearer block below each end of the bearer plate, with the support plates nailed to the bearer plates and blocks. Usually there is an intermediate bearer block for each bearer plate. In the case of a block pallet, the base usually comprises a respective longitudinal base board below, and nailed to, the blocks of each side bearer plate and a lateral base board below and nailed to a respective block of each bearer plate.
With both bearer and block pallets, the pallet, and a load thereon, is able to be lifted by the tines of a fork lift device inserted into a cavity or a respective cavity defined between the side bearers, below the load support boards and, if provided, above the base. Damage to pallets is a relatively frequent occurrence, due to repeated impacts of the support or base boards by the tines in lifting the pallet, more specifically by the uprights from which the tines extend. Damage usually is to an end support board or a transverse end base board extending across the ends of the bearers, with damage being more frequent for end support boards than for end base boards by a factor of about 2 to 1. However, base boards also can be damaged by being dragged on hard surfaces such as concrete, while dragging can dislodge base boards.
Damage to the end support or base board necessitates pallets frequently needing to be taken out of service for repair. Eventually, the cumulative effect of damage and repair results in the need for a pallet to be discarded. Both repair, and replacement of a discarded pallet, represents a substantial cost factor. The damage frequently results from or involves movement of the end board relative to its bearers with a significant component parallel to the interface between the end board and bearers. This causes bending of the nails, to a somewhat S-shape which causes bruising of surrounding timber. Also, the bending tends to align the nails with the forces generating the movement, facilitating withdrawal of the nails from the end board or the bearers.
SUMMARY OF THE INVENTION
The present invention is concerned with providing an improved joint structure. In one preferred form, there is provided a pallet which has joints according to the invention and which, while not entirely eliminating the above cost factors, enables them to be reduced substantially. The pallet of the invention can be of the bearer form or of the block form.
A joint according to the invention is provided between two components of which at least one is of timber. The joint includes a nail plate provided between the components, and nails driven through one component and the nail plate, into the other component.
Each component may be of timber. Alternatively, one may be of timber and the other of another suitable material, such as a suitable grade of plastics material or light gauge steel plate. The components may comprise an end board and a bearer of a pallet, and reference to an end board and a bearer in the following description and claims is to be understood as illustrative of other components between which a joint according to the invention may be formed.
A pallet according to the invention has at least two laterally spaced bearers, and a plurality of laterally extending support boards extending over and secured to an upper surface of each bearer. The pallet also may include a base and, where this is the case, the base may include a plurality of laterally extending base boards extending under and secured to a lower surface of each bearer. As in the known forms of pallet, the support and, where provided, the base boards are in the form of elongate boards and, while successive support boards can abut, they usually are slightly spaced. However, a pallet according to the invention is strengthened, at a joint between at least one bearer and a lateral end board, by provision of a nail plate therebetween or within the bearer and by nails driven through the end board and nail plate, into the bearer. The end board is a support board or a base board which extends at ends or sides of the pallet.
Preferably a respective nail plate is provided between the lateral end board and each side bearer, to strengthen the pallet at each of two corners between which the end board extends. Where there is an intermediate bearer, a further nail plate can be provided between it and the lateral end board. The pallet can be further strengthened by a respective nail plate being provided between an end support board and the upper surface of each of the bearers, and between a base board and the lower surface of each of the bearers. In each case, the arrangement can be arranged at one end of the pallet or at each of its ends.
In the case of a bearer pallet, the nail plate of a join is provided between the end board and bearer. The same applies in the case of a block pallet where the end board is a base board, with the nail plate provided between the base board and a bearer block. However, where the end board is a support board of a block pallet, the or a respective nail plate of a join may be between the support board and the bearer plate of the bearer, and/or between the bearer plate and a block of the bearer.
In a joint according to the invention, the nail plate is substantially fixed relative to the one of the components of the joint in which the nail plate teeth are embedded. The portion of nails of the joint within the one component is substantially constrained against bending. Thus, with forces tending to cause relative movement between the components, parallel to the nail plate, bending of the nails is possible substantially only in the portion of each which is within the other component. As that portion of each nail is short relative to the overall nail length, the nails are substantially more resistant to bending under the action of a given force than would be the case if that force acted on the nails over their full length in the absence of a nail plate.
It is preferred that a respective nail plate be provided between each end board and each bearer. However, where a respective nail plate is to be provided between only one end board and each bearer, the end board preferably is a support board in the case of a bearer pallet and a base board in the case of a block pallet.
The nail plates, as will be appreciated, are formed from s
Chen José V.
Pryda PTY LTD
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