GB2088068A - Devices for Checking the Slope of Ladders - Google Patents

Abstract

A device for use in checking that a ladder is positioned at a correct angle to the horizontal comprises a body 14 having flat top face 17 which carries a spirit level 20 and which is at right angles to flat end face 18 and inclined to flat end face 19 at an angle corresponding to the desired angle of inclination of the ladder. Thus when face 19 is placed against the front face 29 of a stile 30 of the ladder, the ladder can be adjusted to bring the spirit level bubble 26 to the correct central position to indicate that the ladder is at the desired angle. Similarly face 18 can be placed against flat side face 34 of the stile 30 to check that the stile is in a vertical plane. <IMAGE>

Description

SPECIFICATION Improvement in or Relating to Devices for use with Ladders This invention relates to devices for use with ladders.

For the safe use of ladders it is important that the ladder is placed at a correct angle to the horizontal.

According to this invention a device for use in checking that a ladder is positioned at a correct angle to the horizontal comprises means engageable with a ladder at two spaced locations, and means providing an indication that, when the device is so engaged, the ladder is at a correct angle to the horizontal.

Preferably the engaging means is adapted to engage a stile of the ladder.

Preferably the engageable means comprises a flat face for engaging the ladder stile.

The indication means preferably comprises a spirit level.

The spirit level may extend along the top of the device.

The device may comprise further means engageable with a stile of a ladder at two spaced locations, and further means for indicating that, when The device is so engaged, the stile is in a vertical plane.

The further engageable means may comprise a further flat face.

The indicating means may act as the further indicating means.

The spirit flat face may extend at right angles to the spirit level.

The device may comprise a body providing said flat faces.

The indicating means may be such that the correct angle is a single angle, or a range of angles.

The invention may be performed in various ways and two specific embodiments with possible modifications will now be described by way of example with reference to the accompanying diagrammatic drawings, in which Fig. 1 shows a device for use with a ladder in one position of use; Fig. 2 shows the device in another position; Fig. 3 is a side view of the device; Fig. 4 is a perspective view of the device in association with a ladder stile; Fig. 5 is a perspective view of part of another device; and Fig. 6 is a vertical transverse section through part of Fig. 5.

It is desirable for safe use of a ladder to place the ladder at the correct angle to the horizontal and vertical. Referring to Fig. 1, where a ladder 10 is placed on a horizontal surface 11 and against a vertical surface 12, the ladder is correctly placed if the distance XY, between the junction X of the bottom of the ladder and the surface 11 and the junction Y beween the surfaces 11, 12, is T the distance YZ between the junction Z between the top of the ladder and the surface 12 and the junction Y; that is if the tangent of angle ZXY is 4 (angle ZXY equals 750 58'). The device 13 is designed to allow a user to readily assess whether the ladder has been placed at this correct angle.

One form of the device is shown in Fig. 4 and comprises a solid body 14, for example of hardened rubber, plastics or wood, has parallel side surface 15, 1 6; a flat top surface 1 7 at right angles to the surfaces 1 5, 1 6; a flat end surface 18 at right angles to the surfaces 15, 16, 17; a flat front end surface 1 9 at right angles to surfaces 1 5, 16; and a bottom surface 20. The angle between surfaces 17 and 19 is 750 58'.

A straight spirit level 20 is secured to the top surface 1 7. The level 20 comprises a generally circular cross-section cylindrical steel case 21 having a flattened surface 22 engaging the surface 17. The case 21 has a window 23 exposing the inner glass holder 24 containing coloured liquid. The holder 24 has the usual spaced parallel markings 25 between which the bubble 26 in the liquid is symmetrically placed when surface 1 7 is horizontal. The level may be held in place by removable adhesive tapes 27, 28.

Thus, in use, the surface 1 9 is placed against the flat front face 29 of a stile 30 of the ladder 10, the ladder is placed against surfaces 11, 12 (for example the ground and a wall) and the angle of the ladder to the wall or other upright surface adjusted until the bubble 26 indicates that the surface 1 7 is horizontal. The ladder is then at the correct angle.

Conveniently the device is sized to be carried in a user's pocket. For example, referring to Fig. 3, AB may be 9.525 cm (3.75 inch), AD may be 10.16 cm (4 inch), CD may be 6.985 cm (2.75 inch). The thickness could be 0.9525 cm (0.375 inch).

It is not essential for the face 19 to be flat and straight. It could have a recess 31, Fig. 3, providing spaced edges 32, 33 lying on the line BC.

It is also desirable for safe use of the ladder, for the stiles to be in vertical planes. In the present example, in which angle BAD is 900, the positioning of the ladder can be checked in this respect by placing face 1 8 against the flat side surface 34 of the stile and adjusting the ladder position until the bubble 26 is correctly positioned between the markings 25, the window 23 having the necessary angular extent. Fig. 2 illustrates this use, surface 34 being at right angles to surface 30.

The device can take other forms. One such is shown in Fig. 5, 6 in which the spirit level is located in a recess 40 in the top surface 1 7 and the surfaces 1 5, 16 are provided with opposed grooves 35 in which are slidable the edges 36 of a guard piece 37 which can be slid over the level as protection against accidental damage.

The device is inexpensive and enables a user readily to assess whether a ladder is correctly positioned in relation to the horizontal and whether the ladder is leaning to one side.

It will be appreciated that the level need not be straight.

Furthermore, although the ladder should be used when placed at the correct angle to the horizontal, there may be circumstances in which the ladder may be used when it is placed within range of angles to the horizontal. By spacing the markings at the appropriate distance apart, the device may be used to check that the ladder is positioned at an angle within this range, the spirit level bubble being between the markings, or engaging one marking, when the ladder is within the range, and extending beyond a marking when the ladder is positioned at an angle outside the range.

It will be appreciated that in use face 19 engages the ladder stile at two locations having separation in the direction of the ladder; and face 18 Fig. 2 engages the side of the stile at two locations of which one is higher than the other so that they have vertical separation.

It will be appreciated that the device could be arranged for engaging both stiles, for example the device of Fig. 4 could be attached to a bar for extending across the ladder and having a face corresponding to face 19 engaging both stiles with the spirit level horizontal; there could be attached a piece for engaging face 34 to locate the device in a lateral direction.

Claims (14)

Claims

1. A device for use in checking that a ladder is positioned at a correct angle to the horizontal comprising means engageable with a ladder at two spaced locations and means providing an indication that, when the device is so engaged, the ladder is at a correct angle to the horizontal.

2. A device as claimed in Claim 1, which is adapted to engage a stile of the ladder.

3. A device as claimed in Claim 2, comprising a flat face for engaging the ladder stile.

4. A device as claimed in Claim 1, or Claim 2, or Claim 3, in which the indication means comprises a spirit level.

5. A device as claimed in Claim 4, in which the spirit level extends along the top of the device.

6. A device as claimed in any preceding claim, comprising further means engageable with a stile of a ladder at two spaced locations and further means for indicating that, when the device is so engaged, the stile is in a vertical plane.

7. A device as claimed in Claim 6, in which the further engageable means comprises a further flat face.

8. A device as claimed in Claim 6 or Claim 7, in which the indicating means acts as the further indicating means.

9. A device as claimed in Claim 6, and Claim 4, in which the further flat face is at right angles to the spirit level.

10. A device as claimed in Claim 3 or Claim 7, comprising a body providing said flat faces.

11. A device as claimed in any preceding claim, in which the indicating means is adapted such that the correct angle is a single angle.

12. A device as claimed in any of claims 1 to 10, in which the indicating means isadapted such that the correct angle is any angle in a range of angles.

1 3. A device as claimed in Claim 12, in which the indicating means comprises a spirit level, in which the level has markings spaced by a greater distance than the length of the bubble in a central position.

14. A device for use in checking that a ladder is positioned at a correct angle to the horizontal substantially as hereinbefore described with reference to and as shown in Fig. 4, or Figs. 5 and 6, of the accompanying drawings.