GB2173148A - Mitre box - Google Patents

Abstract

A mitre box (1) has a pair of aligned slots (4) in its upright walls (3). Each slot contains a saw-guiding precision gate of predetermined width (A), each precision gate being defined by a pair of parallel elongate members (5) made of hardened metal. The elongate members (5) are positioned in complementary apertures (6) formed in the upright walls (3). <IMAGE>

Description

SPECIFICATION Mitre box This invention relates to a mitre box.

A mitre box is an open-ended box having aligned slots in its upright walls. Usually, the slots are inclined at 45" to the longitudinal axis of the box. The slots are used to guide a saw for cutting a mitred jointing surface on a piece of material placed in the mitre box. Known mitre boxes are made of soft materials such as wood, and have the disadvantage that the slots which guide the saw rapidly wear, owing to the action of the sawblade on the sides of the slots. Wear of the guide slots results in inaccurate guidance of the saw, and hence to the production of inaccurate mitred jointing surfaces.

The aim of the invention is to provide a mitre box which does not suffer from this disadvantage.

The present invention provides a mitre box having a pair of aligned slots in its upright walls, each slot containing a saw-guiding precision gate of predetermined width, each precision gate being defined by a pair of parallel elongate members made of hardened metal, the elongate members being positioned in complementary apertures formed in the upright walls.

Advantageously, each of the elongate members is a cylindrical rod made of hardened steel, the rods being positioned in bores formed in the upright walls, said bores merging with the slots so that each of the rods protrudes into the adjacent slot. Preferably, each of the rods protrudes into the adjacent slot by about 0.15 millimetres.

Preferably, the mitre box is made of aluminium.

Alternatively, the mitre box may be made of rigid thermoplastics material, in which case it can be formed by moulding.

A mitre box constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of the mitre box; Figure 2 is an end elevation of the mitre box; and Figure 3 is a side elevation of the mitre box.

Referring to the drawings, a mitre box 1 is constituted by a base 2 and a pair of parallel upright walls 3. The mitre box is made of aluminium, and has a pair of aligned slots 4 in its upright walls 3.

Each of the slots 4 is inclined at 45" to the longitudinal axis of the box 1. A pair of hardened steel dowel rods 5 are associated with each of the slots 4. Each of the rods 5 fits into a bore 6 drilled vertically into the associated upright wall 3. The bores 6 are such that each of the rods 5 protrudes into the adjacent slot 4 by about 0.15 millimetres. Each pair of rods 5 defines a precision gate having a predetermined width A. The slots 4 each have a predetermined width B. The width B is larger by 0.3 millimetres than the width A, so that the slots 4 are clearance slots. Although not shown, each of the bores 6 is of stepped construction, so that the corresponding rod 5 is a friction fit therein only at the lower end thereof.

In order to make the mitre box 1, the box is placed in a jig and the bores 6 are drilled. The slots then are formed in the upright walls 3, the previously-drilled bores being used for locating the box in a further jig during this process. The rods 5 are then fitted into the bores 6.

The aligned pairs of rods 5 define precision gates for guiding the blade of a saw during the cutting of a mitred jointing surface on a piece of material placed in the box 1. Because the rods 5 are made of hardened steel, they are substantially impervious to wear resulting from the action of the sawblade. Consequently, the mitre box 1 is capable of extensive use, whilst ensuring the production of accurate mitred jointing surfaces.

Obviously, the mitre box 1 described above could be modified in a number of ways. For example, the upright walls 3 could be provided with further pairs of aligned slots and precision gates. In particular a pair of aligned slots and precision gates could be provided for cutting pieces of material at 90 to the longitudinal axis of the box 1. In this case, the additional pair of slots and precision gates would be positioned directly opposite one another and inclined 90" to the longitudinal axis of the box 1.

It would also be possible to make the mitre box out of a hard thermoplastics material. In this case, the entire box (including the bores for the hardened steel rods) could be moulded.

1. A mitre box having a pair of aligned slots in its upright walls, each slot containing a saw-guiding precision gate of predetermined width, each precision gate being defined by a pair of parallel elongate members made of hardened metal, the elongate members being positioned in complementary apertures formed in the upright walls.

2. A mitre box as claimed in claim 1, wherein each of the elongate members is a cylindrical rod made of hardened steel, the rods being positioned in bores formed in the upright walls, said bores merging with the slots so that each of the rods protrudes into the adjacent slot.

3. A mitre box as claimed in claim 2, wherein each of the rods protrudes into the adjacent slot by about 0.15 millimetres.

4. A mitre box as claimed in any one of claims 1 to 3, wherein the mitre box is made of aluminium.

5. A mitre box as claimed in any one of claims 1 to 3, wherein the mitre box is made of rigid thermoplastics material.

6. A mitre box as claimed in claim 5, wherein the mitre box is formed by moulding.

7. A mitre box substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Mitre box This invention relates to a mitre box. A mitre box is an open-ended box having aligned slots in its upright walls. Usually, the slots are inclined at 45" to the longitudinal axis of the box. The slots are used to guide a saw for cutting a mitred jointing surface on a piece of material placed in the mitre box. Known mitre boxes are made of soft materials such as wood, and have the disadvantage that the slots which guide the saw rapidly wear, owing to the action of the sawblade on the sides of the slots. Wear of the guide slots results in inaccurate guidance of the saw, and hence to the production of inaccurate mitred jointing surfaces. The aim of the invention is to provide a mitre box which does not suffer from this disadvantage. The present invention provides a mitre box having a pair of aligned slots in its upright walls, each slot containing a saw-guiding precision gate of predetermined width, each precision gate being defined by a pair of parallel elongate members made of hardened metal, the elongate members being positioned in complementary apertures formed in the upright walls. Advantageously, each of the elongate members is a cylindrical rod made of hardened steel, the rods being positioned in bores formed in the upright walls, said bores merging with the slots so that each of the rods protrudes into the adjacent slot. Preferably, each of the rods protrudes into the adjacent slot by about 0.15 millimetres. Preferably, the mitre box is made of aluminium. Alternatively, the mitre box may be made of rigid thermoplastics material, in which case it can be formed by moulding. A mitre box constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of the mitre box; Figure 2 is an end elevation of the mitre box; and Figure 3 is a side elevation of the mitre box. Referring to the drawings, a mitre box 1 is constituted by a base 2 and a pair of parallel upright walls 3. The mitre box is made of aluminium, and has a pair of aligned slots 4 in its upright walls 3. Each of the slots 4 is inclined at 45" to the longitudinal axis of the box 1. A pair of hardened steel dowel rods 5 are associated with each of the slots 4. Each of the rods 5 fits into a bore 6 drilled vertically into the associated upright wall 3. The bores 6 are such that each of the rods 5 protrudes into the adjacent slot 4 by about 0.15 millimetres. Each pair of rods 5 defines a precision gate having a predetermined width A. The slots 4 each have a predetermined width B. The width B is larger by 0.3 millimetres than the width A, so that the slots 4 are clearance slots. Although not shown, each of the bores 6 is of stepped construction, so that the corresponding rod 5 is a friction fit therein only at the lower end thereof. In order to make the mitre box 1, the box is placed in a jig and the bores 6 are drilled. The slots then are formed in the upright walls 3, the previously-drilled bores being used for locating the box in a further jig during this process. The rods 5 are then fitted into the bores 6. The aligned pairs of rods 5 define precision gates for guiding the blade of a saw during the cutting of a mitred jointing surface on a piece of material placed in the box 1. Because the rods 5 are made of hardened steel, they are substantially impervious to wear resulting from the action of the sawblade. Consequently, the mitre box 1 is capable of extensive use, whilst ensuring the production of accurate mitred jointing surfaces. Obviously, the mitre box 1 described above could be modified in a number of ways. For example, the upright walls 3 could be provided with further pairs of aligned slots and precision gates. In particular a pair of aligned slots and precision gates could be provided for cutting pieces of material at 90 to the longitudinal axis of the box 1. In this case, the additional pair of slots and precision gates would be positioned directly opposite one another and inclined 90" to the longitudinal axis of the box 1. It would also be possible to make the mitre box out of a hard thermoplastics material. In this case, the entire box (including the bores for the hardened steel rods) could be moulded. CLAIMS

1. A mitre box having a pair of aligned slots in its upright walls, each slot containing a saw-guiding precision gate of predetermined width, each precision gate being defined by a pair of parallel elongate members made of hardened metal, the elongate members being positioned in complementary apertures formed in the upright walls.

2. A mitre box as claimed in claim 1, wherein each of the elongate members is a cylindrical rod made of hardened steel, the rods being positioned in bores formed in the upright walls, said bores merging with the slots so that each of the rods protrudes into the adjacent slot.

3. A mitre box as claimed in claim 2, wherein each of the rods protrudes into the adjacent slot by about 0.15 millimetres.

4. A mitre box as claimed in any one of claims 1 to 3, wherein the mitre box is made of aluminium.

5. A mitre box as claimed in any one of claims 1 to 3, wherein the mitre box is made of rigid thermoplastics material.

6. A mitre box as claimed in claim 5, wherein the mitre box is formed by moulding.

7. A mitre box substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.