FENCE

Field of the Invention

[0001] This invention relates to apparatus for shaping wood and to a method of making a wood panel or fence.

Background to the Invention

[0002] Timber is typically cut into straight lengths by the use of circular saws or band saws of the type present in every timber yard. For fencing purposes, wood may be cut into thin strips which can be nailed to horizontal supports held between posts, or mounted into frames to form fencing panels which are then mounted between upright posts. In some forms of panel, the thin strips or planks are woven between uprights in the frame to form a pleasing appearance of panel, the weaving depending on the strips or planks being sufficiently thin to have some flexibility. [0003] An alternative form of fencing panel is woven from thin poles (split where necessary) of hazel, willow or the like, the weaving being achieved while the poles are relatively freshly cut and exhibiting their natural flexibility.

[0004] While woven forms of fencing panel are attractive in appearance, they are relatively labour-intensive in their manufacture, and are more difficult to transport, especially those woven from poles or split wood, because of their bulk.

[0005] Panels and other articles formed by using the natural flexibility of thin wood also require a fairly sturdy structure to restrain the forces set up by bending the materials. [0006] Shaping straight timber into curves can also be achieved by heating the wood, typically by the application of steam, and then bending the heated wood around a former and maintaining the bend until the wood is cooled, when the curved shape will be retained. While this technique is typically used to form elements of furniture of relatively high value, the cost of the procedure precludes its use for fencing and the like.

Summary of the Invention

[0007] One aspect of the present invention provides apparatus for shaping wood, comprising a carriage having a front pair of wheels and a rear pair of wheels, the carriage mounting a saw blade and a saw motor for driving the saw blade to perform a sawing action transversely of the carriage, the front pair of wheels being arranged to run on a first pair of guide rails and the rear pair of wheels being arranged to run on a second set of guide rails extending parallel to the first set of guide rails, a bed for receiving the wood to be cut being located between the rails, the first and second guide rails being formed with a vertically varying profile configured to achieve the desired cut shape of the wood, the profiles of the first set of guide rails being displaced horizontally with respect to the profiles of the second set of guide rails by a distance corresponding to the dis- tance between the axes of rotation of the front and rear wheels, and drive means being provided to propel the carriage along the rails to follow the vertically varying profile.

[0008] The saw is conveniently a band saw.

[0009] The drive means may comprise a flexible drive member attached at each end thereof to the carriage, or an endless flexible drive member attached at one point therealong to the carriage, the flexible drive member passing around a wheel at each end of the apparatus, and means for rotating one of the wheels. The means for rotating one of the wheels is conveniently a drive motor, although a hand crank could be used. The drive member may be a chain. [0010] The saw motor may be an electric motor, but is suitably an internal combustion engine, since this avoids the need to supply electric power to a movable item.

[0011] The guide rails are suitably mounted in such as manner as to be readily removable, facilitating their replacement to change the profile to be cut. [0012] Another aspect of the invention provides a method of making a fence, comprising cutting a plurality of timber components having a generally sinusoidal profile, securing a spaced series of posts in the ground, and locating the components between the posts so that the peaks and troughs of the sinusoidal profile correspond to the positions of the posts, each successive component being positioned so that the peaks and troughs are opposite in phase to the last, thereby creating a woven appearance.

Brief Description of the Drawings

[0013] In the drawings, which illustrate exemplary embodiments of aspects of the invention:

Figure 1 is a schematic perspective view of a wood shaping apparatus; Figure 2 is top plan schematic view of the apparatus of Figure 1 ;

Figure 3 is a diagrammatic side elevation of the apparatus;

Figure 4 is a top plan view of a fence; and

Figure 5 is a side elevation of the fence of Figure 4.

Detailed Description of the Illustrated Embodiment

[0014] Referring first to Figures 1 to 3, the apparatus comprises a band saw 1 configured to cut horizontally, mounted in a carriage 2. In the drawing, the motor driving the band saw is omitted for the sake of clarity. The carriage 2 is mounted on front 3 and rear 4 wheels, which are suitably formed with a circumferential groove so as to be able to engage with a respective thin steel guide rail 5 or 6 mounted on a fixed base of the apparatus. The outer guide rails 6 are engaged by the rear wheels 4 which are mounted to the outside of the carriage 2, while the inner guide rails 5 are engaged by the front wheels 3, which are mounted a small distance inwardly of the rear wheels 4 (it will be appreciated that the terms "front" and "rear" in relation to the wheels on the carriage are considered relative to the movement of the carriage during cutting, i.e. to the direction in which the teeth of the band saw are facing, and that it is not critical to the invention which pair of wheels engages the inner or outer guide rails). [0015] The guide rails 5 and 6 are each formed with a vertically-varying profile configured to produce the shape that it is desired to cut in the timber, but are longitudinally offset one from the other by a distance related to the wheelbase of the carriage, i.e. the distance between the respective wheel axes of rotation. As may be seen from Figure 3, this results in the saw blade being presented to the wood at the correct angle for the direction of cut as it varies according to the profile of the guide rails, the cutting line being indicated at 7 in the Figure. A mirror image guide rail may be mounted above at least one of the guide rails 5 and 6, preferably the outer guide rails 6, to assist in preventing the carriage from becoming de-railed in use.

[0016] The carriage may be propelled along, and held on to, the guide rails 5 and 6 by means of a drive member (not shown) such as a cable or chain which passes over a wheel (sprocket wheel, in the case of a chain) and is attached along its length to the carriage 2, in the case of an endless drive member, or with each end attached to the carriage. The carriage can be driven by a hand- wheel or a motor connected to one of the wheels to effect a cut, and is then returned to the start for the next cut.

[0017] One application of the apparatus is in the manufacture of fencing components, of the type illustrated in Figures 4 and 5. Typically, a number of elongate pieces of timber are located in the apparatus, supported on a bed between the wheels, and a first cut is effected by driving the carriage along the apparatus as hereinbefore described. While the pieces of timber might be rectangular in initial cross-section to produce uniformly-shaped components, it would be possible to use round logs or the like to produce variable shapes. In the case of a fence component, a continuous wavy profile is desired, as may be seen from Figure 4. The first cut therefore creates in the upper surface of the piece of timber a wavy profile, with the excess timber being removed as waste. For the second and successive cuts, the saw assembly is lowered by an amount equal to the desired thickness of the fence components. The compo- nents thus have a uniform thickness along their length, the wavy profile not requiring bending of the timber and thus not creating any undesired tension in the component. Typically, by using a number of pieces of timber side-by-side each of the desired height of the components being produced, the result would be components ready for use.

[0018] To construct a fence using the components, which are readily transported to the desired location in stacked form and thus occupying the minimum of space, a series of spaced posts 10 may be driven into the ground along the desired line of the fence, or otherwise secured in the desired positions, the spacings being determined by the half lengths of the waves cut by the apparatus, and the cut components 12 are then slid downwards around the posts, each successive component being flipped relative to the last to form the "wo- ven" appearance which can be seen from Figures 4 and 5. A strong and durable fence can thus be constructed quickly and easily, with pleasing appearance and good screening properties.

[0019] While the invention has been described with reference to fencing, it will be appreciated that panels can be constructed in the same general way for a wide variety of uses, including shelters and panels to be incorporated into furniture items.