GB2265018A

GB2265018A - Builders collapsible set square

Info

Publication number: GB2265018A
Application number: GB9204845A
Authority: GB
Inventors: Eric Lyon
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-03-06
Filing date: 1992-03-06
Publication date: 1993-09-15
Also published as: GB9204845D0

Abstract

This invention of a builders collapsible set square comprises of two box section legs 1 and 5 being connected together at one end by means of a hinge pin 3 and brackets 4 enabling the legs to be opened to 90 degrees and closed parallel to each other. A pair of locking arms 6 are provided to lock open the legs at 90 degrees. <IMAGE>

Description

BUILDERS COLLe3S13LE SET SQUIRE This invention relates to a builders collapsible folding set square for use in the building trade.

Ninety degree set squares are used extensively in the setting out stage of houses and other brick structures for the correct alignment at right angles of walls. These set squares are fabricated on site using scrap pieces of timber and nails.

Because of their flimsy construction and awkwardness in handling they are usually discarded after use.

Although relatively cheap in material terms, wooden squares require time both to piece them together and to check that the angle is indeed ninety degrees.

This invention of a builders collapsible set square comprises of two box section legs being connected together at one end by means of a hinge device enabling the legs to be opened to 90 degrees and closed parallel to each other. A pair of locking arms are provided to lock open the legs at 90 degrees.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which Figure 1 shows in perspective the collapsible square in the open position in which it is used.

Figure 2 shows a plan view of the collapsible square in its folded position in which it is carried and stored.

Figure 3 shows in detail the locking arrangement whereby the two legs are held locked at 90 degrees to each other.

Referring to the drawing, the set square comprises of two box section legs 1 and 5 which are joined together at one end by means of a hinge pin 3. This pin 3 is held by means of two brackets 4, which are themselves attached ridgedly to leg 5.

Due to the arrangement of the hinge pin 3 and brackets 4, it is impossible to open the two legs more than 90 degrees. When fully open the side face of one leg abuts the top face of the other leg. The two legs 1 and 5 are kept at ninety degrees to each other by means of locking arms 6, hinge pins 2 and centre pin 8.

The combined length of the two locking arms 6 (there are two sets of locking arms) is slightly greater than the distance between the holes for the hinge pins 2. This allows the locking arms to snap into position when the legs 1 and 5 are opened. To prevent the locking arms from going too far a lug 10 is provided on one arm to act as a stopper Spacers 9 are of differing thicknesses so as to allow the locking arms 6 to fold onto each other when the square is in its folded position. Recesses 7 are provided to accommodate the hinge pin 8. Friction provided by the locking arms 6 and pins 2 keep the square in this folded position.

To open the square the free ends of the legs are grasped by the hands and opened out. The apex of the 'V' so formed is then placed on the ground and pressure applied with the foot in the area of hinge pin 8. The locking arms will then snap and lock into position.

The square is folded up by inverting it and applying downward pressure with the palm of the hand in the area of hinge pin 8 The legs in the folded position will be touching and parallel to each other.

Claims

CLhlMS

1. A builders collapsible set square comprising of two box section legs being connected together at one end by means of a hinge device enabling the legs to be opened to 90 degrees and closed parallel to each other, a pair of locking arms to lock open the legs at 90 degrees.

2. A builders collapsible set square as claimed in Claim 1 wherein the ninety degree angle is set due to the side face of one leg abbuting the top face of the other leg.

3. A builders collapsible set square as claimed in Claim 1 or Claim 2 wherein the locking arms are provided with lugs to prevent further inward movement.

4. A builders collapsible set square as claimed in any preceding claims, wherein the legs are provided with one hinged pin.

5. A builders collapsible set square substantially as described herein with reference to Figures 1-3 of the accompanying drawing.