GB2109120A - Improvements relating to angle determining devices - Google Patents

Abstract

An angle determining device comprises a pair of rigid arms 7, 10 pivotably connected at one end at a point 1 to which is attached a rod 6. A tube 5 is slidably mounted on the rod 6, and further arms 8, 11 are coupled to the tube 5 and connect with the ends of the respective arms 7, 10, such that as the tube 5 is moved along the rod 6 the angle subtended by the arms 7, 10 is varied. The rod 6 is graduated in degrees and the position of the tube 5 indicates the angle between the arms 7 and 10. <IMAGE>

Description

SPECIFICATION Improvements relating to angle determining devices.

One of the problems associated with determining the corner angles of existing walls of rooms and also other walls, ceiling, floors and other structural members, particularly in older properties with irregular and out of square walls and so forth varying greatly in angle at the corners.

For persons who regularly record existing angles such as Surveyors, Architects, Builders, the otherwise existing methods available are relatively sophisticated, of limited accuracy and crude and/or time consuming.

At present a theodolite may be used, an adjustable set square may be used (limited to a relatively small range of angular adjustments), an adjustable square may be used and then offered up to a protractor, templates may be cut and angles taken or measurements taken and the angles worked out geometrically by graphical methods or resolved mathematically. All demanding a considerable amount of care and time to ensure any degree of accuracy.

The object of this invention is to provide quick and accurate method of determining angles of corners by means of a relatively simple device.

One example of such a device is described as follows see Diagram A At position 1 at the end of the device there is a pivot point where rigid arms 7 and 10 are joined and so is rigid bar 6, the two arms and the bar are free to move in one axis in relation to each other the pivot may be a pin or other pivoting means. Arms 7 and 10 would normally but not necessarily be of equal length.

Attached to arms 7 and 10 at points 2 and 3 are pivots attached to rigid arms 8 and 11 these arms would normally but not necessarily be of equal length and would in turn likewise be normally but not necessarily of equal length to arms 7 and 10.

At the opposite ends of rigid arms 8 and 11 to pivots 2 and 3 there are pivots 4 and 1 2 the corresponding part of the pivots fixed either side of tube 5 the pivots described are free to move in a single axis only.

The rigid bar 6 previously described, slides through tube 5. Tibe 5 has in one version a locking means 9 to lock bar 6 in relation to tube 5 when required. Bar 6 is suitably calibrated in degrees as an example By engraving a metal bar as an example but transparent or other materials may be used with alternative methods of indicating the calibration.

In order to measure the angle of the corner of a room the device is placed with all arms and the bar in the horizontal plane with the locking device 9 unlocked, the tube 5 is moved towards or away from pivot 1 until arms 7 and 1 0 are in complete (or as near as compiete as possible) contact with the walls.

For narrow angles tube 5 will be further from pivot 1 for wide angles tube 5 will be near pivot 1.

When not in use tube 5 may be pivoted as far from pivot 1 as possible thereby closing the device making it convenient for carrying in a brief case or similar Levelling indicators such as level bubbles may be affixed or integral in one or several of the arms 7, 10, 8, 11 or alternatively incorporated in or on tube 5. Tension or compression springs may be used to take up any play or backlash in the device in some versions, springs may in some instances allow even easier use of the device by providing a reaction that would facilitate single handed use.

The springs may be direct acting or indirect via levers, arms or cables intension perhaps with the use of pulleys. Alternative forms of device may include for example an additional member 13, this member provides additional width to the device. Member 1 3 would be swung up from the handing down positiion to the horizontal (in the same plane as arms 7, 8, 10 and 11 in diagram A. Member 1 3 in providing extra width to the device pervents point 1 from snuggling in tightly to the corner of a wall this is particularly valuable when the corners are ill defined or when there are obstructions such as pipes; the sides of member 1 3 are normally but not necessarily parallel.

The device may take many different forms or combinations. In another version arms 7 and 10 may be projected rear-wards to provide a greater length of contact which will normally contribute to greater accuracy on uneven walls such as often found in older properties. The length of wall samples is longer and discrepancies more likely to be averaged out The use of the described device is not limited to determining the angle of walls but may be used for other applications, other uses include use by engineers, carpenters, contractors and other trades and professions for use in horizontal and vertical attitudes for example.

A preferred arrangement is shwon on enclosed drawing X which features an additional member at the front pivot point and additional width at the tube end The purpose of this is to provide a blunt nose in order that corner obstructions may be cleared when determining an angle. Corner obstructions include pipes, battens, and so forth. Other features in the preferred arrangment include a release button as described in the drawing and also a suitable knob which may be placed against the stomach-or chest of the user holding the device into the corner whilst the angle is determined.

Other features include the use of a square central rod providing a more useful surface of engraving and providing a reference means to reduce or eliminate twisting of the device when used.

In another form the device may be constructed as per drawing Y. This uses two arms hinged at one pivot point with a protractor centered on the pivot point and locked to one of the arms, the movement of the other arm will give the angle of a corner. The problem with this device is that the protractor would have to be of a reasonable size to ensure accuracy and that any corner obstructions would tend to foul the protractor. This may be overcome by increasing the width of the arms sufficiently in construction or by swinging the tail of the arm as indicated in the drawing Y Drawing Z indicates a corner angle determining device without provision for obstacle clearance in a corner, such a device may be used with a suitable block with parallel sides when obstacle clearance is necessary.

Claims (11)

1. An angle determining device comprising a pair of arms joined at one end to define an angle and pivotable relative to one another to vary the angle, and an indicator attached to each arm so that the position of the indicator relative to the arms or to a reference indicates the angle subtended by the arms.

2. A device as claimed in claim 1, wherein the indicator is constrained to move generally in the plane of the arms.

3. A device as claimed in claim 1 or claim 2, wherein the indicator is constrained to move along a line passing through the intersection of the arms or of extensions thereof.

4. A device as claimed in claim 3, further comprising a guideway extending along said line and wherein the indicator is slidably mounted on the guideway.

5. A device as claimed in claim 4, wherein the indicator is a tube movable on the guideway and is connected to the arms by further respective arms.

6. A device as claimed in claim 4 or claim 5, wherein the guideway is graduated with a scale in degrees or other angular measurement.

7. A device as claimed in any one of the preceding claims, wherein the arms are mounted at respective ends of a rod or bar.

8. A device as claimed in any one of the preceding claims, including means for increasing or varying the width of the arms.

9. A device as claimed in claim 8, wherein the width increasing means are resilient or profiled so that they will fit around pipes or other obstructions.

10. A device as claimed in claim 1, wherein the indicator is a protractor mounted on one arm and centered at the pivot point between the arms.

11. An angle determining device substantially as hereinbefore described with reference to the accompanying drawings.