GB2220067A

GB2220067A - Bubble level for ladders

Info

Publication number: GB2220067A
Application number: GB8814924A
Authority: GB
Inventors: John Keen; Nicholas John Starling
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-06-23
Filing date: 1988-06-23
Publication date: 1989-12-28
Also published as: GB8814924D0

Abstract

A level to achieve correct placement of a ladder against a wall comprises a body member (1) having at least one side (2) sloped such that in conjunction with the top plate (3) the angle of slope corresponds to the normally correct ladder angle (1 in 4). The upper part of the body (1) incorporates a fluid filled tube (4) having an air bubble (5) which is approximately 50% of the length of the tube. The top of body (6) incorporates two adjacent triangular shaped apertures (7 and 8). When the ladder (9) is too close to a wall (10), for example, the bubble (5) adopts a position in which it is viewable in window (8) whereas the fluid in the tube is viewable in window (7). When in the correct position the bubble will be viewable in both apertures. The fluid may be coloured, e.g. red. <IMAGE>

Description

TITTLE Device to facilitate correct placement of a ladder.

This invention relates to a device to facilitate the correct placement of a ladder against a wall for example.

It is an object of this invention to provide a simple means which may be placed against a ladder or permanently secured thereto and which unambiguously indicates whether or not the ladder is correctly placed with the optimum angle of slope against a wall. It has been determined that the correct angle of slope of a ladder should be 1 in 4.

According to this invention there is provided a device to facilitate correct placement of a ladder against a wall, the device comprising a tube partially filled with a liquid and containing a bubble, the tube being viewable through two adjacently placed apertures in a masking plate and arranged such that the bubble is visible in both apertures when the tube is horizontal with the bubble being viewable in one or other only of the apertures when the tube is tilted one way or the other away from the horizontal.

In a preferred construction the tube is mounted within a body member having sides which are angled such that when placed against the side of a ladder the tube will be horizontal when the ladder is positioned at the correct angle of slope.

The tube may be positioned in the top part of the body member with the masking plate forming a closure thereover. Preferably the apertures are in the form of a pointer or triangular with the fluid being of a distinctive colour, for example red, such that when a ladder is not in the correct sloping position the red fluid appears in one aperture and the clear bubble appears in the other so as to indicate a direction in which to move the base of the ladder to achieve the correct slope.

This invention also contemplates a ladder incorporating a device substantially as hereinbefore described.

The invention thus provides a spirit level but in which the bubble is made larger than normal and arranged in conjunction with the length of the fluid filled tube such that in one or other of the limit positions one window shows the fluid whereas the other window shows the bubble. The apertures being arranged in conjunction with the bubble such that in the correct position with the tube horizontal the bubble is visible in both apertures simultaneously.

One embodiment according to the invention is shown by way of example in the accompanying drawings wherein: Figures la, b and c show respectively top view of the device, a side view of the device and the ladder position when too close to a wall, Figure 2 shows similar views to Figure 1 when the ladder is correctly sloped, and Figure 3 shows similar positions when the ladder is too far from the wall and the base.

Referring to the drawings, the device may comprise a body member 1 comprising a housing of which at least one of the sides 2 is sloped such that in conjunction with the top plate 3 the angle of slope corresponds to the normally correct angle (1 in 4) of a ladder against a wall for the position of maximum stability. The upper part of the body 1 incorporates a fluid filled tube 4 having an air bubble 5 which is approximately 50% of the length of the tube. The top of body 6 incorporates two triangular shaped apertures 7 and 8 which are adjacently positioned and, as may be seen in Figure 1, when the ladder 9 is too close to a wall 10 the bubble 5 adopts a position in which it is viewable in window 8 whereas the fluid in the tube is viewable in window 7.If the fluid is made of a dominant colour such as red then the direction of the arrow of window 7 will indicate the direction in which the base of the ladder must be moved to achieve a correct slope.

Figure 2 shows the position when the slope is correct and, as may be seen, the bubble 5 is viewable simultaneously in both of the windows 7 and 8.

In Figure 3 the position is shown wherein the ladder 9 is moved too far away from the wall and in this case the bubble is viewable through window 7 whereas the fluid is viewable through window 8. This indicates that the base of the ladder must be moved in the direction of the arrow defined by window 8 to achieve the correct position.

The device may be constructed in the form of a unit of which the side 2 may be placed against a ladder to determine the correct position or in an alternative embodiment the device may be incorporated into a ladder or be fixed thereto using screw fastenings or adhesive.

A particular feature of this invention is establishing an appropriate relationship between the dimension of the bubble 5 within the tube 4 and the positioning of the windows 7 and 8 in relation thereto.

Claims

1. A device to facilitate correct placement of a ladder against a wall, the device comprising a tube partially filled with a liquid and containing a bubble, the tube being viewable through two adjacently placed apertures in a masking plate and arranged such that the bubble is visible in both apertures when the tube is horizontal with the bubble being viewable in one or other only of the apertures when the tube is tilted one way or the other away from the horizontal.

2. A device according to Claim 1, wherein the tube is mounted within a body member having sides which are angled such that when placed against the side of a ladder the tube will be horizontal when the ladder is positioned at a correct angle of slope.

3. A device according to Claim 1 or 2, wherein the tube is positioned in the top part of the body member with the masking plate forming a closure thereover.

4. A device according to any preceding claim, wherein the apertures are in the form of a pointer or are triangular with the fluid being of a distinctive colour, such that when a ladder is not at the correct slope the fluid appears in one aperture and the clear bubble appears in the other so as to indicate a direction in which to move the base of the ladder to achieve the correct slope.

5. A device substantially as described herein and exemplified with reference to the drawings.

6. A ladder incorporating the device of any preceding claim.