GB2360245A - Apparatus for cutting a tenon in an end of a fencing arris rail - Google Patents

Abstract

Apparatus for cutting a tenon in an end of a fencing arris rail of generally triangular cross-section comprises a support member 5 for receiving and guiding the arris rail so that the rail is capable of liner displacement in a direction along its length. A primary cutting device 3 is arranged to cut into the uppermost edge of the rail, and a pair of secondary cutting devices 4 are arranged to cut into the two side surfaces either side of and below the uppermost edge of the rail. Drive means, such as motors 1, 2, activate the primary and secondary cutting devices, and control means are provided for operating the drive means. The apparatus may be portable.

Description

2360245 APPARATUS FOR ADZING ARRIS RAIL TENONS Many wooden fence

constructions require the use of timber arris rails, to which the individual fence planks are fastened. The arris rails are almost universally of constant triangular cross section along their length. The arris rails need to be inserted into apertures, usually mortices, cut into the supporting fence posts. From the timber or fencing supplier, the arris rails as supplied do not fit the mortices in the posts and each end of the arris rail needs to be cut into tenons which will fit the corresponding mortices.

Usually, tenons are cut manually by means of an adze, by the fencing contractor or installer. This leads to problems and is time-consuming. There is a substantial variation in the quality of tenons adzed manually into the ends of such arris rails. The quality of tenons cut by adze is largely dependent upon the skill of the installer. The finished product i.e. the arris rail with manually adzed tenons cut into each end can have different shapes and sizes. This leads to poor fitting of such tenons into the fence post mortices and consequently varying strengths of the combined mortice and tenon joint.

Apart from the varying quality, because the arris rails are supplied uncut, considerable time is required to cut by this manual acizing of tenons at each end of all arris rails needed for any given fencing installation.

It is therefore desirable to provide a machine for acIzing tenons at each end of an arris rail, not only to save time but also to improve quality and reduce or eliminate the variation in shape and size of such tenons. It is also desirable to provide a process for acizing tenons in arris rails, using such a machine, which reduces the time required and which can be performed by unskilled operatives.

Accordingly we have now devised such a machine and such a process.

2 According to one aspect of this invention, there is provided an apparatus for cutting a tenon at an end of a fencing arris rail of generally triangular cross section, which apparatus comprises:

(a) a support member for receiving and guiding an arris rail whereby the rail is capable of linear displacement in a direction along its length, (b) a primary cutting device arranged to cut into the uppermost edge of said rail, when said rail is located in said support member and caused to engage said primary cutting device, (c) a pair of secondary cutting devices each arranged to cut into the two side surfaces either side of and below the said uppermost edge of said rail, when said rail is located in said support member and caused to engage said secondary cutting devices, (d) drive means for activating the primary cutting device, (e) drive means for activating the secondary cutting devices, and (f) control means for operating the drive means (d) and (e).

Preferably the support member is a guide rail which prevents lateral displacement of the rail whilst permitting said linear displacement. This may be carried into effect by the use of a channel-section member wherein the channel width corresponds closely to the width of the arris rail, permitting a close fit thereof.

The support member may be provided with a tensioned mechanism which, in use, abuts the end of the arris rail and which reduces or even eliminates the tendency of the rail to 'snatch' or 'jerk' during the cutting process, upon insertion into the apparatus via the support member. In practice, such a tensioned mechanism can be a spring-loaded stop member such as a bar, against which the end of the arris rail being cut, abuts and which may also be used to assist removal of the rail once the tenon has been fashioned, by spring pressure tending to urge the rail out of the apparatus, in a linear direction within the constraints of the said support member.

- 3 Preferably the primary cutting device comprises a cutting wheel with a circumferential blade or blades, the wheel being mounted for rotation such that its cutting edge(s) are adapted, in use, to engage and cut into the uppermost edge of the arris rail.

The secondary cutting devices can be of substantially the same construction, and may each also comprise a similar cutting wheel with a circumferential blade or blades, but each located at 9011 with respect to the said primary cutting device. Both said secondary cutting devices are conveniently mounted for rotation such that their cutting edge(s) are adapted, in use, to engage and cut into the said side surfaces at the end of the arris rail.

Both secondary cutting devices may be directly connected to a motor, preferably electric, of approximate power output in the region of 1-2 horsepower.

The primary cutting device is preferably indirectly driven by a motor, such as an electric motor of some 1-2 horsepower output, such as via a belt-driven rotatable shaft. This shaft may be supported in bearings housed in appropriate mounts spaced either side of the said support member.

The apparatus for cutting a tenon conveniently includes a generally flat mounting surface wherein bearings are located either side of the support member, in which are provided shafts to drive both said secondary cutting devices, such as directly from motors located underneath said mounting surface. The apparatus can be mainly enclosed by a cowling having an aperture for entry therein of one end of an arris rail to be cut into a tenon. The apparatus preferably mimics the action of an adze in the appearance of the cut tenons.

In order that the invention may be illustrated, more easily appreciated, and readily carried into effect by those skilled in the art, an embodiment thereof will now be described purely by way of non-limiting example, with reference to the accompanying drawings, wherein:

4 Figure 1 is a generalised isometric sketch of an apparatus according to this invention, Figure 2 is a view of the end of a typical triangular cross section fencing arris rail before cutting, Figure 3 is a view of the rail of Figure 2, after the end has been cut into a tenon through use of the present apparatus, and Figure 4 shows a detail of a modification to facilitate and enhance throughput.

Referring to the drawings and initially to Figure 1, the apparatus is shown as a small workstation in that a main body and machine frame 7 has a generally flat mounting surface 7a upon which rests a support member 5 in the form of a channel section trough.

The arris rail (not shown) is presented via this trough to the cutting parts, shielded by safety cowling 6 with entrance 6a for the workpiece rail. The cowling is box-shaped and is affixed to the mounting surface 7a, preferably by hinge to allow access to the covered components.

Within the safety cowling 6, there are two spaced upright mounts 10, having bearings 10a if required, in which a driven shaft 10b is rotatably mounted. The shaft 10b has a pulley 11 connected via belt 12 to a 1.5 HP electric motor 1 affixed to the mounting surface 7a of the machine frame 7. The motor 1 is electrically driven e.g. by mains electricity and operable by switchgear 8 to which it is electrically connected on the exterior of the machine frame.

The driven shaft 101b has a primary horizontal cutter wheel 3 securely affixed thereto, and circumferentially located, spaced apart cutting blades 3a adapted, in use, to cut into the uppermost edge of the rail workpiece. Actuation of the motor 1 via swtchgear 8 causes the shaft and hence this cutting wheel 3 to rotate, causing the edges of the blades 3a to cut the wood as it is pushed along the support trough 5.

Also within the cowling, there are a pair of secondary vertical cutter wheels 4, with blades 4a, each wheel being similar to the primary wheel 3 except that they are mounted for rotation in a plane which is perpendicular to the cutting plane of the primary cutting wheel 3. The secondary cutting wheels 4 are securely affixed to a shaft 4b, driven by separate electric motors 2 also of about 1.5 HP. These motors 2 are also operable by the electric switchgear 8, to which they are electrically connected. The motors are located internally of the machine frame 7, and the shafts 4b are mounted in suitable bearings, if required, housed in the mounting surface 7a.

At the end of the supporting trough 5, a spring loaded abutment bar 9 is provided. This helps minimise 'snatch' or 'jerk' whilst cutting proceeds, and also helps to eject the rail workpiece when cutting is finished. It also helps to improve uniformity of tenon size at the cut ends of each arris rail.

Referring to Figures 2 and 3, unprocessed arris rail 13 is entered manually into the trough 5 and pushed manually towards the three cutting wheels, rotated by the three separate electric motors. Snatching is resisted by the spring loaded bar 9. A rod may be used within the spring. As shown in Figure 3, the arris rail 13a has a tenon 13b cut into its end, by the present apparatus, which mimics the effect of manually creating an adzed tenon.

With reference to Figure 4, the machine is adapted to both facilitate and enhance throughput of arris rails for cutting. A frame 14 has a small platform 15 mounted thereon. The platform has a mechanism 17, which may be spring-loaded, coupled to an elongate board 18. The board is capable of linear reciprocating displacement and is intended to co-operate with the support member 5 and be coplanar therewith. The mechanism 17 is operable by an operator's paddle 16. Sideways movement of the paddle by an operator causes the board 18 to feed an arris rail loaded thereon (not shown) along the support member and into the cutting devices. This sub-assembly helps to automate the cutting process and increase the throughput of arris rails. The mechanism 17 may be electrically powered or manually operated.

6 Use of the present apparatus can ensure, even using unskilled labour, more regularly shaped and sized tenon ends. In turn this leads to closer, tighter fits in the post mortices (not shown). Not only is the mortice and tenon joint more pleasing to look at but it is tighter and stronger. The principal advantage, however, is in the economics of time, since by using the machine considerable time can be saved in creating the 'adzed' tenons and less wastage in the case of excessive manual adzing leading to spoilage of the rail.

The apparatus could be fabricated to a smaller scale to become a portable apparatus used on site. It may be possible to eliminate one or two of the presently preferred three motors, by appropriate drive coupling means.

7.

Claims (17)

Claims:

1. An apparatus for cutting a tenon at an end of a fencing arris rail of generally triangular cross section, which apparatus comprises:

(a) a support member for receiving and guiding an arris rail whereby the rail is 5 capable of linear displacement in a direction along its length, (b) a primary cutting device arranged to cut into the uppermost edge of said rail, when said rail is located in said support member and caused to engage said primary cutting device, (c) a pair of secondary cutting devices each arranged to cut into the two side surfaces either side of and below the said uppermost edge of said rail, when said rail is located in said support member and caused to engage said secondary cutting devices, (d) drive means for activating the primary cutting device, (e) drive means for activating the secondary cutting devices, and (f) control means for operating the drive means (d) and (e).

2. Apparatus as claimed in claim 1 wherein said support member is a guide rail effective to prevent lateral displacement of an arris rail but permitting said linear displacement.

3. Apparatus as claimed in claim 2 in which the guide rail comprises a channel section member wherein the channel width corresponds closely to the width of the arris rail.

4. Apparatus as claimed in any preceding claim in which the support member is provided with a tensioned mechanism which, in use, abuts the end of the arris rail and which reduces or eliminates any tendency of the rail to snatch or jerk during the cutting process.

5. Apparatus as claimed in claim 4 in which said tensioned mechanism comprises a spring-loaded stop member against which the end of an arris rail being cut can abut.

6. Apparatus as claimed in any preceding claim in which said primary cutting device comprises a cutting wheel with circumferential blade(s), the wheel being mounted for rotation whereby its cutting edge(s) is (are) adapted, in use, to engage and cut into the uppermost edge of the arris rail.

7. Apparatus as claimed in claim 6 wherein the secondary cutting devices are of substantially the same construction as the said primary cutting device, but each being mounted at 9T with respect to the said primary cutting device.

8. Apparatus as claimed in claim 7 in which both said secondary cutting devices are conveniently mounted for rotation whereby their cutting edges are adapted, in use, to engage and cut into the said side surfaces at the end of the arris rail.

9. Apparatus as claimed in any preceding claim wherein both secondary cutting devices are directly connected to a motor.

10. Apparatus as claimed in any preceding claim wherein the primary cutting device is indirectly driven by a motor.

11. Apparatus as claimed in any preceding claim, which is mainly enclosed by a cowling having an aperture for entry therein of one end of an arris rail.

12. Apparatus as claimed in any one of claims 1 to 11 substantially as herein described.

13. Apparatus as claimed in any one of claims 1 to 11 substantially as herein illustrated in any figure of the accompanying drawings.

14. A method of cutting the end of an arris rail into a tenon which involves the simultaneous use of three cutting devices, one such device being positioned at 90' with respect to the other two such devices.

15. A method as claimed in claim 14 which involves use of an apparatus as claimed in any one of claims 1 to 13.

16. A method as claimed in claim 14 or 15 substantially as herein described.

9-

17. A method as claimed in claim 14 or 15 substantially as herein illustrated in any figure of the accompanying drawings.