GB2123743A - Mitre block - Google Patents

Abstract

Saw guides 5, 6, 7, 8 enable coving to be cut by placing it face down on a base 2. The plane of the cut being at approximately 55 DEG , preferably 54.7 DEG , to the base and walls 3, 4 when measured in the plane of a wall and the base respectively. Alternatively the saw guides 24, 29 located one on each side of a base 19 are adjustable iongitudinally of the base and are pivotable relative to the base. The guides may be pivotally mounted on a plate which is rotatable in the plane of the base to alter the angle of cut across the base. <IMAGE>

Description

SPECIFICATION Mitre block The present invention relates to a mitre block for cutting mitres, in particular for cutting mitres in ceiling cove or coving.

A conventional mitre tool comprises a channel formed by a base and a pair of vertical sides opposite one another. Slits are provided in the sides to guide a saw and a mitre is cut with the material held in the channel against one of the sides. The siits are vertical and angled at 900 or 450 across the channel.

A first aspect of the present invention provides a mitre block comprising a planar base having an axial direction and a wall extending substantially perpendicularly from the base and substantially parallel to the axial direction, wherein a saw guide is formed in the wall to enable a saw cut to be made such that the plane of the cut is at an angle of approximately 550 to the plane of the base when measured in the plane of the wall and approximately 550 to the plane of the wall when measured in the plane of the base. Very preferably the angles are 54.70.

Preferably two, substantially parallel, walls are provided.

Preferably a pair of said saw guides are provided to enable the two cuts necessary to form a 900 join, to be made in material having a generally isosceles right angled triangular cross-section, the material being placed with its wider face against the base. Hence the material presents a low profile to the walls of the tool thus avoiding the need for deep saw cuts, which may be impossible with a tenon saw, and correspondingly high walls necessary for ensuring adequate guidance of the saw above the level of the saw teeth.

Preferably the mitre block is also provided with saw guides to enable a saw cut to be made at 900 to the base and at 900 to the walls.

A second aspect of the present invention provides a mitre block comprising a base and a pair of saw guides extending upwardly from the base, wherein the saw guides are located on opposite sides of the base and are movable relative to one another along the base, and the angle of the saw guides to the base is adjustable.

Preferably rails are provided running longitudinally of base so that material to be cut can be held on the base against a rail. Adjustment of the relative position of saw guides along the base and their angle to the base enables a mitre to be cut at any conceivable angle within the dimensions of the tool.

By calcuiating the required angle of cut the tool can be used to cut skirting boards with mitred joints to fit faceted bay windows, decorative frames with any number sides, the sides being dished at an angle if desired, and the mitring of ceiling cove.

The invention will be further described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a plan view of a first embodiment of the invention; Fig. 2 is a side view of the embodiment of Fig. 1; Fig. 3 is an end view of the embodiment of Fig. 1; Fig. 4 shows a sheet of directions which may be provided on the embodiment of Fig. 1; Fig. 5 is a plan view of a second embodiment of the invention; Fig. 6 is a side view of the embodiment of Fig. 5; Fig. 7 is an end view of the embodiment of Fig. 5; Figs. 8a and 8b are a side and a plan view of a saw guide of the embodiment of Fig. 5; Figs. 9a and 9b are a plan view and side view of a frame.

The mitre tool of Figs. 1 to 3 comprises a base 2 and walls 3, 4 which are parallel to one another and extend upwardly from the base 1 at opposite edges thereof. The tool may be made of any suitable material such as wood, plastics or metal, hardwood is preferred.

A saw guide in the form of a slot 5 is formed in one wall, 4, at an angle of 550 to the base 2 and at an angle of 550 to the plane of the wall 4 when measured in the planes of the wall and base respectively. A corresponding slot 6 is formed in the opposite wall 3 in the plane of the slot 5 to provide a first line of cut across the base 2. Wall 3 may be omitted, wall 4 preferably being of increased thickness to ensure adequate guidance of the saw. A second pair of slots 7, 8 is formed in the walls 3, 4 respective at angles of 55" to the base 550 to the walls to provide a second line of cut which traverses the base 2 at an angle of 70" to the first line of cut.

To minimise the length of the base the guides 5, 6 and 7, 8 may be arranged so that the lines of cut across one another.

The slots are opened out at the lower region to accommodate the saw teeth to allow the saw to be inserted from the side and so avoid wear of the upper region of the guides by the saw teeth.

Slots 9, 10 are formed directly opposite one another in the walls 3, 4 at 900 to the base to provide a third line of cut for use in forming straight butt joints.

Fig. 4 shows a diagram 11 which may be provided on the base 2 to give directions as to the saw cut(s) to be made to form right angle joints in cove to fit the cove into a corner 12 of a room or around the reentrant right angles 13 of a chimney breast. To keep a saw away from the diagram 11, rails 14, 1 5 are provided on the base 2. During a sawing operation the cove is supported on the rails 14, 1 5, the saw guides 5 to 10 extending down to the rails 14, 1 5.

Aiternatively, the rails may be omitted. The diagram may be printed elsewhere on the device or provided on an instruction sheet or label.

To form a corner joint 12, a length of cove is placed in the base 2 of the mitre tool 1, across the line 1 6 of the diagram 11, with the cove face downwards on the base 2. A cut is made using the saw guides 5, 6 and the piece on side A of the line 1 6 is kept. A second length of cove is placed across the line 17 and a cut made using the saw guides 7, 8. The piece on side B of line 17 is kept.

To form a reentrant corner joint 1 3 cuts are made as before but the pieces on sides D and C of lines 1 6 and 1 7 respectively are kept.

Figs. 5 to 7 show a second embodiment 18. A base 19 is made of hardwood and has a replaceable surface 20 for wear.

Stops 21,22 against which material to be cut is held, are provided on one side of the base 19. A metal angle 23 is fixed at one side of the base and a saw guide 24 is carried between a wall 25 of the angle and the side of the base. Angle 23 has a slot 26 and the guide 24 has a stud 27 which projects through the slot. The guide is held in position by a wing nut 28 tightened on the stud 27, against the side 25 of the angle 23. The guide may be slid along the base and its angle to the base adjusted by loosening the wing nut 28. A second guide 29 is located on a stud, not shown, which projects from side 30 of the base, approximately midway of the length of the base. The guide is clamped in position buy a wing nut 31.

Base 1 9 has a rail 32 on its underside, which rail may be used to hold the tool in a vice.

Figs. 8a and 8b show the guide in side and plan view.

In use, the saw guides are adjusted to the same angle V to the base, and guide 24 is slid along to give the desired angle of cut H across the base.

To produce a mitre joint in material having two perpendicular mirror planes in the axial direction, e.g. material of rectangular cross-section, a single cut can be made and one piece of material inverted to fit the other.

With other material two cuts are normally required.

Referring to Figs. 9a and 9b, which show a frame made from rectangular cross-section material the angles H and V of the guides may be calculated as follows: H=sin-' (Sin2P +cos2P/sin2Q)-1/2 V=tan-' (tan Q/Sin P) where Q is the half angle of a corner of the frame, and P is the dish angle of the frame, being the angle of the face 34 of length of the material relative to the plane of the frame. This face is placed downwards on the base of the tool during cutting.

Typical values are as follows: Nos. of sides 4 6 8 Angle of guides/0 Dish anglelo H V H V H V 10 45.4 80.1 60.4 84.3 67.8 85.9 25 47.8 67.1 62.4 76.3 69.4 80.1 45 54.7 54.7 67.8 67.8 73.7 73.7 Preferably, simple protractors or calibrations are supplied with the tool for common requirements.

In another embodiment, not illustrated, the guides are supported on a plate which is pivotally attached to the base to be rotatable in the plane of the base to alter the angle of cut across the base.

The guides are pivotally mounted on the plate to allow for the change in the angle of cut to the base.

Prefrably the guides pivot about axes in the plane of the base. Members may be provided connecting the top of saw guides to rigidify the structure and increase support for the saw across the base.

Claims (14)

Claims

1. A mitre block comprising a planar base having an axial direction and a wall extending substantially perpendicularly from the base and substantially parallel to the axial direction, wherein a saw guide is formed in the wall to enable a saw cut to be made such that the plane of the cut is at an angle of approximately 55 to the plane of the base when measured in the plane of the wall and approximately 55 to the plane of the wall when measured in the plane of the base.

2. A mitre block as claimed in claim 1, wherein two substantially parallel walls are provided, a saw guide being provided in each wall to form a set of saw guides.

3. A mitre block as claimed in claim 2, wherein the wails extend upwardly from opposite edges of the base.

4. A mitre block as claimed in any one of claims 1 to 3, wherein there are provided two saw guides or sets of saw guides, the planes of the saw cuts enabled by the sets being at an angle to one another.

5. A mitre block as claimed in any one of claims 1 to 4, wherein the base is elongate in the axial direction.

6. A mitre block as claimed in any one of claims 1 to 6, wherein a pictorial guide is provided on the base.

7. A mitre block as claimed in any one of claims 1 to 6, wherein support rails are provided on the base to support material to be cut and space said material from the base.

8. A mitre block as claimed in any one of claims 1 to 7, wherein the saw guides are slots cut in the walls.

9. A mitre block substantially as hereinbefore described with reference to Figs. 1 to 3 of the accompanying drawings.

10. A method of cutting a mitre in coving to form a right angled join, which method comprises laying the coving face down and cutting the coving in a plane which is approximately 55 to the horizontal and vertical planes when measured in the vertical and horizontal planes respectively.

11. A method of cutting coving, substantially as hereinbefore described with reference to the accompanying drawings.

1 2. A mitre block comprising a base and a pair of saw guides extending upwardly from the base, wherein the saw guides are located opposite one another across the base and are movable relative to one another longitudinally of the base, and the angle of the saw guides to the base is adjustable.

1 3. A mitre block as claimed in claim 11, wherein one of the saw guides is fixed in position on the base.

14. A mitre block as claimed in claim 11 or 12, wherein the saw guides pivot in parallel planes, perpendicular to the base.

1 5. A mitre block as claimed in claim 11, 12 or 13 wherein the guides are located on opposite sides of the base.

1 6. A mitre block substantially as hereinbefore described with reference to Figs. 5, 6, 7, 8a and 8b of the accompanying drawings.

1 7. The features hereinbefore disclosed, or their equivalents, in any novel combination.