This invention relates to panels which may be used for forming enclosures, and to an apparatus for forming such panels.

It is commonly desired nowadays to form outdoor enclosures from panels of attractive appearance. In particular it is known to provide panels with diagonally running lines which may be produced from a series of slats running diagonally or from a panel onto which strips are fixed in the diagonal direction. However such panels are relatively complex to produce.

We have now devised a panel which is attractive in appearance yet can be formed relatively easily. We have also devised an apparatus for forming the panel.

Thus in accordance with this invention, there is provided a rectangular panel which is formed on one or both sides with a series of parallel, diagonally-extending grooves.

Preferably the panel is a wooden panel and preferably it comprises a panel of plywood. Preferably each groove comprises one edge which is inclined. Preferably the other edge is substantially normal to the surface of the panel.

If the panel is formed with the diagonally extending grooves on both sides, then preferably the grooves on one side are inclined in the opposite direction to the groove in the other side, rather than the two sets of grooves being parallel to each other.

The panel is of attractive appearance and can be used to form enclosures or partitions either outdoors or indoors, or can be applied to existing walls etc to provide a decorative effect.

Also in accordance with this invention, there is provided an apparatus for forming a series of parallel, diagonally extending grooves in a side of a rectangular panel,

the apparatus comprising a guideway for receiving the panel, and groove cutting head mounted for movement along a track inclined across the guideway.

Preferably the groove cutting head includes a plurality (e.g. three) cutters for cutting a corresponding plurality of grooves in the side of the panel, and the apparatus is arranged to index the panel forwards along the guideway by a predetermined amount after the cutting head has made one traverse, so that it can then cut another group of grooves in the panel, and so on until the panel has been formed with grooves at intervals across its entire surface.

Preferably the apparatus is arranged to cut a series of grooves in both sides of the panel in one pass of the panel through the apparatus. Preferably both series of grooves are formed in the panel at one station, in which case preferably the apparatus has two cutting heads (one for each side of the panel), each movιble along a track inclined across the guideway: preferably these two tracks are inclined in opposite directions, so that the grooves in the opposite sides of the panel are cut on opposite diagonals rather than the series on one side parallel to the series on the other side.

Preferably the apparatus is fed with successive plywood panels from a stack of such panels. Preferably each successive panel is slid from the top of the stack and onto a feed-in table to the groove cutting apparatus.

In accordance with this invention, there is provided a mechanism for balancing a stack of panels so that as each panel is removed from the top of the stack, the stack rises so that the new top panel occupies the position previously occupied by the preceding top panel.

Preferably in this mechanism, the stack is supported on a platform which is suspended from a cable around about a drum, and a cam wheel is mounted for rotation with the drum and has a cable extending over a progressively increasing- radius surface of the cam wheel to suspend a weight. Then as a

top panel is removed from the stack, momentarily the weight exerts a greater moment than the lightened stack on the rotary assembly and causes this assembly to turn, but in so doing brings the assembly into a position wherein the weight is suspended from a slightly smaller radius point of the cam surface, and exerts a slightly smaller moment. Thus, an equilibrium is reached between the moments exerted by the weight in the stack, but now with the stack at a position one panel thickness higher than previously.

Embodiments of this invention will now be described by way of examples only and with reference to the accompanying drawings in which:

FIGURE 1 is an elevation of a panel in accordance with this invention;

FIGURE 2 is a section on the line II - II of Figure 1;

FIGURE 3 is a diagrammatic plan view of an apparatus for forming grooves in a rectangular panel;

FIGURE 4 is a partial view of the upper cutting head and its mounting and drive arrangements;

FIGURE 5 is a partial view of the lower cutting head and its mounting and drive arrangements;

FIGURE 6 is a schematic view of a feed mechanism of the apparatus; and

FIGURE 7 is a diagram showing a balancing mechanism for a stack feeder of the apparatus.

Referring to Figure 1, there is shown a square panel 10 of plywood which is formed on one or both sides with a series of parallel, diagonally extending groves 12. If there are grooves on both sides of the panel, these lie on opposite diagonals rather than lying parallel to each other. As shown in Figure 2, each groove has one edge 14 inclined to the surface ofthe panel, and one edge 16 which is substantially normal to the surface of the panel and as shown each groove is triangular in section. In use, especially for outdoor use, the panel is erected with the inclined edges 14 below the edges 16 to aid the

run-off of water: if the panel is grooved on both surfaces, then the inclined edges of both series of grooves lie towards the same edge of the panel (which is to be the bottom edge of the panel when erected).

Referring to Figure 3, there is shown an apparatus for forming the grooving in the two sides of a square or rectangular plywood panel. The apparatus includes a guideway for the passage of successive panels in a straight line. The apparatus also has upper and lower cutting heads 20,22 mounted for movement along tracks 24, 26 which are oppositely inclined to the direction of passage of the panels through the apparatus. A drive lotor 40 is provided which is coupled by a chain transmission to the two cutting heads for driving the two heads 20, 22 simultaneously along their respective tracks: in so doing each cutting head cuts three parallel grooves in the respective side of the panel. When both cuttting heads reach the ends of their respective tracks, an indexing means steps the panel forward a predetermined distance along the guideway, then the drive motor 40 drives the cutting heads back along their tracks to cut another three grooves alongside the previous group of three grooves. The process is repeated until the panel has been stepped through the apparatus (in the direction of the arrow shown in Figure 3) , having been formed with parallel, diagonal grooves at regular intervals across the full width of both sides thereof. As shown, each cutting head comprises a drive motor 30 rotating a shaft 32 on which three rotary cutters 34 are mounted at spaced intervals.

Referring more particularly to Figures 4 and 5, the apparatus comprises a flat table 25 for supporting the plywood panel P in its successive positions as it passes through the apparatus, the table having a diagonal slot in it for the lower cutting head to engage the underside of the panel supported on the table.

The drive motor 40 for reciprocating the two cutting heads is mounted below the table and drives a shaft 41

via a chain 42. This shaft 41 drives a chain 43 for the upper cutting head 20, and, via a connecting chain 44 and a shaft 45, also drives a chain 46 for the lower cutting head 22. The upper and lower cutting heads 20, 22 are coupled to the respective chains 43, 46 so that with motor 40 driven in one direction, the two cutting heads are driven to and fro along their respective diagonal paths.

Referring to Figure 4, the guideway for the upper cutting head comprises a pair of parallel, spaced-apart tubes 24 (one shown). The upper cutting head includes a trolley 21 which engages around the respective tubes for sliding along these. From one side of the trolley a plate 48 projects, this plate having a slot accommodating a pin 49 which is clamped to the drive chain 43. The drive motor 30 of the cutting head is mounted on top of the trolley and the shaft 32 which it drives is mounted below the trolley.

The guideway for the lower cutting head 22 (Figure 5) comprises a pair of parallel, spaced square tubes 26 (one shown). The lower cutting head comprises a trolley consisting of two opposite plates 23 (one shown) which mounts upper, lower and intermediate rollers 50, 51 and 52.. The upper and lower rollers 50, 51 engage the top and bottom surfaces of the square tube 26 and the intermediate roller 52 engages the inwardly facing side of this tube. The plate 23 has a projecting portion 53 formed with a slot which accommodates a pin 54 which is clamped to the drive chain 46. The lower cutting head has a chassis 55 which is pivoted at its opposite sides to the two plates 23. The drive motor 30 is mounted to the bottom of this chassis and the shaft 32 which it drives is mounted to the top of the chassis. Because the chassis is pivoted to the plates 23, the lower cutting head 22 is able to pivot as a unit and so follow varying contours in the plywood panel P being processed.

Figure 6 shows diagramatically a mechanism for feeding a plywood panel to and indexing it through the groove cutting apparatus of Figures 3 to 5. This mechanism comprises an

elongate rack 60 which extends lengthwise of a feed-in table 61, which is provided along its opposite sides with guides 62 (Figure 3) - for the opposite edges of the panel. At its trailing end, the rack 60 is provided with a pivoted pawl 63. When the rack 60 is retracted (i.e. to the right in Figure 6), it passes over the top of a stack S of plywood panels, the pawl 63 striking the lead edge of the top panel and being depressed. However", when the rack 60 has been retracted sufficiently for the pawl 63 to lie beyond the trailing edge of the top panel in the stack, it projects outwards under the bias of a spring with which it is provided. Then when the rack 60 is advanced (i.e. moved to the left in Figure 6), the pawl 63 engages the trailing edge of the panel to draw this from the top of the stack and onto the feed-in-table 61. Once one group of three grooves has been cut in each surface of the panel (i.e. after one pass of the cutting heads), the panel is advanced by the appropriate distance by means of an indexing mechanism 70. This mechanism comprisea an arm 71 pivoted at one end to a wheel 72 and having its other end 73 hooked downwardly for engaging within successive notches 74 spaced along the top of the rack 60. Thus, when the cutting heads of the groove cutting apparatus have completed a pass (and passed beyond the edgesof the panel) , the wheel is automatically rotated, with the effect of advance ing 'the hooked end 73 of the arm 71 through a predetermined stroke (thus advancing the rack 60 and hence the panel P) , and thereafter retracting the hooked end 73 of arm 71 so that it disengages from its notch 74, slides along the top of the rack 60 and re-engages with the preceding notch.

A. mechanism is provided for the stack S of plywood panels jiich ensures that as each panel is slid off the top of the panel,' the whole stack automatically lifts through a distance corresponding to the thickness of one panel, so that the new top part l of the stack is in the same vertical position as was occupied by the previous top panel. The mechanism is diagramatically shown in Figure 7, and comprises a cylindrical

drum 80 around which is wound a cable 81. From this cable is suspended a platform 82 on which the stack S of plywood panels rests. The drum 80 is mounted on a shaft to which is also mounted a cam wheel 84, which has a curved surface 86 which progressively increases in radius from the drum axis over a predetermined angle: in the case shown the radius increases from zero to R over 180°. A cable 85 has one end fixed to the cam wheel at its lesser-radius (zero radius) position, extends over the surface of the cam wheel and has a weight W suspended from its other end. In operation, initially the weight W counterbalances the weight of the pull stack when the larger radius of the cam surface is horizontal as shown, i.e. the weight exerts the greatest moment on the cam wheel. When a panel is removed from the top of the stack, momentarily the moment exerted by the weight is greater than that exerted by the lightened stack, causing the assembly to rotate (in the counterclockwise direction as seen in Figure 7), allowing the stack to rise. However, this rotation turns the cam wheel so that a slightly smaller radius of this occupies the horizontal position, and so the weight W exerts a slightly smaller turning moment on the assembly. An equilibrium is reached, wherein the new top panel of the stack occupies the position held previously by the panel which has been removed. This operation is repeated each time another panel is removed from the top of the stack.