GB2201251A

GB2201251A - Try square

Info

Publication number: GB2201251A
Application number: GB08802261A
Authority: GB
Inventors: Geoffrey Betts
Original assignee: Betts & Sons Ltd
Current assignee: Betts & Sons Ltd
Priority date: 1987-02-18
Filing date: 1988-02-02
Publication date: 1988-08-24
Anticipated expiration: 2008-02-02
Also published as: GB8802261D0; GB2201251B; GB8703767D0

Abstract

A try square having a stock (10) and an upstanding blade part (12). So that the square is more versatile than a conventional try square it has an auxiliary blade part (28) with a quadrant piece (30) having a series of notches (34) in which a pawl member (36) can be engaged to locate the auxiliary blade part (28) at any one of a number of different angles. A spirit level unit (24) is also provided on stock (10). <IMAGE>

Description

Try square.

The invention. relates to a try square.

Try squares are well known and usually comprise a stock or basal part of rectangular outline shape, this part being of fairly substantial thickness, and an upstanding blade part secured at one end of the stock, this also being of rectangular outline shape but being of much lesser thickness than the stock and being located intermediate the thickness of the latter.

The stock or basal part of a try square is usually solid, being generally made of wood in the case of a joiner's square and being of solid metal in the case of an engineer's square. In either case, the uses to which a conventional try square can be put are limited. It can, for example, be used to make a line at right angles to an edge or to check that the corners of a frame or right angle joint are accurate. The object of the invention is to provide a try square which is more versatile than a conventional try square.

According to the invention, there is provided a try square with a basal part or stock and an upstanding blade part, the basal part or stock having a spirit level and a pivotally mounted auxiliary blade part with a quadrant piece having a series of notches at its periphery into any one of which a spring loaded pawl member can be engaged to locate said auxiliary blade member at any one of a number of different angles relative to a basal surface of the stock, a slidably mounted release member in the side wall of the stock being provided for releasing the pawl from the notches at the periphery of the quadrant piece. Preferably, the release member will be movable to a position in which it holds the pawl member in an inoperative position.The auxiliary blade part may be capable of being "clicked" into place at 15 degree angular intervals between 0 degrees and 90 degrees to the basal surface of the stock. Means provided for securing the auxiliary blade in position at any angle between 0 degrees and 90 degrees relative to the basal surface of the stock may be constituted by a clamping lever which engages a screwthreaded stud extending through an arcuate slot in the quadrant piece. Preferably, the auxiliary blade part will be capable of being fully retracted into the stock with only an extreme end portion of said auxiliary blade part projecting into the right angle notch formed where the upstanding edge of the upstanding blade part stops just short of the plane containing the basal surface of the stock.

In order that 'the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only with reference to the accompanying drawings, of which:- Figure 1 is a side view of a try square embodying the invention, shown with one cover plate removed from a stock or basal part, Figure 2 is a perspective view of the stock from one side, Figure 3 is a side view of the stock from the other side, and Figure 4 is an exploded sectional view on the line 4-4 in Figure 1.

Referring now to the drawings, the try square there illustrated comprises a stock or basal part generally indicated 10 and an upstanding blade part 12. As shown, the stock is of fairly substantial thickness but the upstanding blade part is of much lesser thickness and is located intermediate the thickness of the stock. The stock and the upstanding blade part are each of rectangular outline shape and are secured together in such a way that the upstanding edge 14 of the blade part makes exactly a right angle with the basal surface 16 of the stock.

The stock is formed in two main pieces 18 and 20 joined together by screws 22 with the upstanding blade part located between them at one end.

Intermediate the ends of the stock 10 there is located a spirit level unit 24, the vial of which is visible from either side of the square through respective windows 26 in the two pieces 18 and 20.

At the end of the stock remote from the upstanding blade part, there is located a pivotally mounted auxiliary blade part- 28. Said blade part 28 is formed integrally with a quadrant piece 30 graduated in degrees of angle between 0 degrees and 90 degrees which can be observed through an aperture 32 in the basal part 20, the aperture being formed with a pointer as shown. In addition, the quadrant piece is provided at its periphery with a series of notches 34 into any one of which a spring loaded and pivotally mounted pawl member 36 can engage as shown in Figure 1. The pawl member is slotted, as shown, for the engagement of a peg 38 formed integrally with a release member 40 a serrated portion 41 of which is exposed for operation by the user through a slot 42 in the basal piece 20.When the release member is moved linearly, in guides flanking the slot 42, in the direction of the arrow in Figure 3, the pawl member 36 is displaced about the axis of the pivot 44 and compresses the spring 46. The auxiliary blade is thus free to move about the axis of the pivot 48 until the pawl member, under the action of the spring 46, is allowed to- return to its operative position in engagement with a particular one of the series of notches 34 in the quadrant piece. The release member can in fact be moved to an extreme position in which it is held until manually returned to its normal position, in which extreme position it retains the pawl member in its inoperative position so that the auxiliary blade is free to pivot through its entire range of movement.

The way in which the release member is held in its extreme position is shown in Figure 4. As shown, the release member in its free condition is of slightly concave shape and is formed with a pair of projections 56 which flank the serrated portion 41.

The guides which flank the slot 42, and in which the release member is movable linearly, are provided with respective notches 58 in which the projections 56 become engaged as the release member is moved -to its extreme position. Alternative means for securing the auxiliary blade in position in this mode of operation are constituted by a clamping lever 50 which engages a screwthreaded stud 52 extending through an arcuate slot 54 in the quadrant piece 30.

With the auxiliary blade part 28 fully retracted into the stock, as shown in full lines in Figure 1, the auxiliary blade is inoperative and the square can be used in the manner of a conventional try square to mark a line at right angles to an edge and, for example, to check that the corners of a frame or right angle joint are accurate. In this fully retracted position, an extreme end portion of the auxiliary blade part projects at 29 into the right angle notch formed where the upstanding edge 14 of the blade part 12 stops just short of the plane containing the basal surface 16 of the stock.

The auxiliary blade part can thus be pivoted outwards very easily when required for use.

However, when the auxiliary blade has been pivoted out of the stock, with the pawl member in operation, it can be locked in any one of the several pre-set positions at 15 degree intervals by said pawl member. The square can thus be used in the manner of a combination square, and any of these pre-set angles in a structure can of course be checked- for truth with reference to the spirit level vial.

With the pawl member held inoperative, the angle of any structure (for example the pitch of a roof) can quite simply be determined by placing the auxiliary blade against the structure and bringing the stock to a horizontal position with reference to the spirit level vial. The square can also be used in the manner of a protractor by pressing the face of the stock against an edge of a workpiece and marking off any angle required.

Thus there is provided a try square which can be used in conventional manner but which in addition is- much more versatile than a conventional try square. That is to say, the auxiliary blade is not only capable of being clicked" into any one of a plurality of pre-set angles but can be rendered freely pivotable when required with an alternative means for securing it in position at any angular setting.

Various modifications may be made. For example, although the auxiliary blade part of the illustrated embodiment is shown to be capable of being "clicked" into place at 15 degree angular intervals between 0 degrees and 90 degrees, it will be understood that it could be "clicked" into other pre-set positions, for example at every 10 degrees.

Claims

CLAIMS:

1. A try square with a basal part or stock and an upstanding blade part, the basal part or stock having a spirit level unit and a pivotally mounted auxiliary blade part with a quadrant piece having a series of notches at its periphery into any one of which a spring loaded pawl member can be engaged to locate said auxiliary blade member at any one of a number of different angles relative to a basal surface of the stock, and a slidably mounted release member in the side wall of the stock being provided for releasing the pawl from the notches at the periphery of the quadrant piece.

2. A try square according to claim 1, in whidh the release member is movable to a position in which it holds the pawl member in an inoperative position.

3. A try square according to either one of the preceding claims, in which the auxiliary blade part is capable of being "clicked" into place at 15 degree angular intervals between 0 degrees and 90 degrees to the basal surface of the stock.

4-. A try square according to either one of claims 2 and 3 in which means provided for securing the auxiliary blade in position at any angle between 0 degrees and 90 degreees relative to the basal surface of the stock are constituted by a clamping lever which engages a screwthreaded stud extending through an arcuate slot in the quadrant piece.

5. A try square constructed and arranged, and adapted to be used, substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

5. A try square according to any one of the preceding claims, in which the auxiliary blade part can be fully retracted into the stock with only an extreme end portion of said auxiliary blade part projecting into the right angle notch formed where the upstanding edge of the upstanding blade part stops just short of the plane containing the basal surface of the stock.

6. A try square constructed and arranged, and adapted to be used, substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS:

1. A try square with a basal part or stock and an upstanding blade part, the basal part or stock having a spirit level unit and a pivotally mounted auxiliary blade part with a quadrant piece having a series of notches at its periphery into any one of which a spring loaded pawl member can be engaged to locate said auxiliary blade part at any one of a number of different angles relative to a basal surface of the stock, and a slidably mounted release member in the side wall of the stock being provided for releasing the pawl from the notches at the periphery of the quadrant piece, said release member being movable to a position in which it holds the pawl member in an inoperative position.

2. A try square according to claim 1, in which the auxiliary blade part is capable of being "clicked" into place at 15 degree angular intervals between 0 degrees and 90 degrees to the basal surface of the stock.

3. A try square according to either one of the preceding claims, in which means provided for securing the auxiliary blade part in position at any angle between 0 degrees and 90 degreees relative to the basal surface of the stock are constituted by a clamping lever which engages a screwthreaded stud extending through an arcuate slot in the quadrant piece.

4. A try square according to any one of the preceding claims, in which the auxiliary blade part can be fully retracted into the stock with only an extreme end portion of said auxiliary blade part projecting into the right angle notch formed where the upstanding edge of the upstanding blade part stops just short of the plane containing the basal surface of the stock.