GB2589630A

GB2589630A - Overcentre clamped ladder steady

Info

Publication number: GB2589630A
Application number: GB1917841.7A
Authority: GB
Inventors: Andrew Weston Paul; Whipps Colin
Original assignee: Siemens Mobility Ltd
Current assignee: Siemens Mobility Ltd
Priority date: 2019-12-05
Filing date: 2019-12-05
Publication date: 2021-06-09
Anticipated expiration: 2039-12-05
Also published as: GB2589630B; GB201917841D0

Abstract

An overcenter clamped ladder steady comprising a ladder support 1 mounted on an overcenter clamp, said clamp comprises a forward clamp half 3 and a rear clamp half 7, rotatably coupled by a hinge pin 8, each having a clamping surface 3a, 7a, a pair of trunnion plates 6 are mounted on the forward clamp half holding a trunnion 9, a T-shaped bar 10 is inserted and adjustable within the trunnion, a pair of clevis plates 11 are mounted on the rear clamp half holding a clevis pin 13 and handle 14, provided with a clevis slot 15 to receive the T-bar rotatably mounted on said pin. The ladder steady may comprise an end stop 16 which abuts a clevis plate when the clamp is in an overcenter position. The clevis plate and handle may also be provided with locking holes 17 for receiving a locking pin 19 (fig.5). Also disclosed is a method of clamping the steady to a support structure.

Description

OVERCENTRE CLAMPED LADDER STEADY

The present invention relates to a ladder steady, in particular an overcentre clamped ladder steady including an 5 overcentre clamp having an open and a closed position and a ladder support mounted on the overcentre clamp.

In many situations when working at height it is necessary to use a ladder to access an area or object of interest from the ground, including horizontal support structures, such as scaffolding, or vertical support structures such as signal poles, lamp posts or utility poles (telephone or electricity or signage). Whilst it is preferable from a health and safety perspective to minimise or eliminate the use of ladders, some operations may only be carried out from a ladder. In such situations it is desirable to be able to tie off the ladder to a rigid structure in order to provide a steady base from which work can be carried out.

Step/leaning ladders are commonly used when accessing signal poles, lamp posts or utility poles for example, but suffer from the disadvantage that signal heads and other equipment installed at the top of the pole may interfere with the positioning of the step/leaning ladder, resulting in the stiles of the ladder being located at some distance from the pole. Aside from this making access to the signals and other equipment difficult this may result in it not being possible to tie off the ladder against the signal pole, lamp posts or utility poles to make it secure. Typically, ladders will be secured to the pole using ladder straps: adjustable webbing straps that are tied around the ladder stiles and around the pole. These have the disadvantages that the ladder strap may slip up or down the pole when the ladder is in use, making it unstable, and are time consuming to both secure and undo.

There therefore exists a need for a ladder steady that is rigid, secure and easy to install and remove from a support structure.

Embodiments of the present invention aims to address these problems by providing, in a first aspect, an overcentre clamped ladder steady comprising: an overcentre clamp having an open and a closed position; and a ladder support mounted on the overcentre clamp; wherein the overcentre clamp comprises a forward clamp half having a clamping surface and a rear clamp half having a clamping surface rotatably coupled to one another by a hinge pin; a pair of trunnion plates mounted on the forward clamp half and adapted to hold a trunnion; a T-bar inserted into the trunnion and adapted to be adjustable within the trunnion; a pair of clevis plates mounted on the rear clamp half and adapted to hold a clevis pin; and a handle rotatably mounted on the clevis pin, the handle being provided with a clevis slot adapted to receive the T-bar when the clamp is in a closed position.

The handle may be provided with an end stop adapted to abut one of the clevis plates when the clamp is in an overcentre 20 position.

The clevis plates and the handle may be provided with locking holes, and the clamp may further comprise a locking pin adapted to be inserted into the locking holes when the clamp 25 is in an overcentre position.

The trunnion may comprise a hole having a screw thread and the T-bar is provided with an opposite screw thread such that the T-bar is rotatable in the trunnion to engage the screw 30 threads.

The forward clamp half and the rear clamp half may be provided with hinge plates, and the hinge pin is inserted into the hinge plates.

Each of the forward clamp half and the rear clamp half may be provided with a resilient material on their clamping surfaces.

The ladder support may be mounted on the forward half clamp.

The clamping surfaces of the forward half clamp and the rear 5 half clamp may be concave.

The trunnion plates may be mounted on the forward clamp half distal from the hinge plates, and the clevis plates may be mounted on the rear clamp half distal from the hinge plates.

Embodiments of the present invention also provide, in a second aspect, a method of clamping the overcentre clamped ladder steady described above to a support structure, comprising: placing the forward clamp half and the rear clamp half around the support structure with the clamp in the open position; receiving the T-bar into and engaging the T-bar with the clevis slot; rotating the handle towards the rear clamp half to cause the forward clamp half and the rear clamp half to grip around the support structure until the end stop engages with the clevis plates and the clamp is in an overcentre position.

The strength of the grip of the forward clamp half and the rear clamp half on the support structure may be adapted by 25 rotating the T-bar within the trunnion to adjust its length.

The locking pin may be inserted into the locking holes in the clevis plates and the handle to lock the clamp into a closed position.

The invention will now be described by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in the open position; Figure 2 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in a first installation position; Figure 3 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in a second installation Position; Figure 4 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in the closed position; Figure 5 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in an overcentre position with a locking pin inserted; Figure 6 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention installed on a vertical support; and Figure 7 illustrates a method of clamping the overcentre 15 clamped ladder steady to a support structure.

The present invention takes the approach of utilising an overcentre clamp having a ladder support mounted thereon to mount the ladder steady on a support structure rigidly, securely and in a manner easy to install and remove from a support structure. The overcentre clamp has an open and a closed position and itself comprises a forward clamp half having a clamping surface and a rear clamp half having a clamping surface rotatably coupled to one another by a hinge pin. A pair of trunnion plates are mounted on the forward clamp half and adapted to hold a trunnion, with a T-bar inserted into the trunnion and adapted to be adjustable within the trunnion. A pair of clevis plates are mounted on the rear clamp half and adapted to hold a clevis pin, having a handle rotatably mounted on the clevis pin, the handle being provided with a clevis slot adapted to receive the Thar when the clamp is in a closed position. This is described in further detail below.

Figure 1 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in the open position. The overcentre clamped ladder steady 100 comprises a ladder support 1 comprising a hollow tube having, in the example illustrated, a nominal diameter of 0.04m and a nominal length of 1.0m. preferably the surface of the ladder support is roughened, by, for example, grit blasting. The ladder support 1 is provided with an end cap 2, which may be of a greater diameter than the tube itself. The overcentre clamp 200 comprises a forward clamp half 3 having a clamping surface 3a and a rear clamp half 7 having a clamping surface 7a rotatably coupled to one another by means of a hinge pin 8. Both the forward clamp half 3 and the rear clamp half 7 are provided with hinge plates 5, and the hinge pin 8 is inserted into the hinge plates 5. Both the forward clamp half 3 and the rear clamp half 7 are made from 0.127m diameter, 0.003m thick steel having a circular hollow section, such that the forward clamp half 3 and the rear clamp half 7 are concave. This enables the forward clamp half 3 and rear clamp half 7 to be fitted around an aluminium or steel signal pole, lamp posts or utility poles with nominal outside diameter of 0.1143m easily. The clamp half dimensions can be altered to suit differing diameter pole types. In addition, both the forward clamp half 3 and the rear clamp half 7 are provided with a resilient material 4 on their clamping surfaces 3a, 7a. This may be rubber, neoprene or other suitable resilient material that creates a cushioned surface having an Increased grip on the support structure when compared to the steel clamping surfaces 3a, 7a.

A pair of trunnion plates 6 are mounted on the forward clamp half 3 and adapted to hold a trunnion 9. Preferably the trunnion plates 6 are mounted distal from the hinge plates 5. The trunnion plates 6 are provided with a hole through which the trunnion 9 is inserted and free to rotate. A T-bar 10 is inserted into the trunnion 9, with the trunnion 9 comprising a hole having a screw thread and the T-bar 10 being provided with an opposite screw thread, such that the T-bar 10 is rotatable in the trunnion 9 to engage the screw threads. Preferably the trunnion 9 is provided with a female screw thread and the T-bar 10 is provided with a male screw thread.

Rotating the T-bar 10 within the trunnion 9 therefore adjusts its length, as described further below.

A pair of clevis plates 11 are mounted on the rear clamp half 7 and are adapted to hold clevis pins 13. Each clevis plate 11 is provided with a hole through which the clevis pins 13 are inserted and screwed tight. A handle 14 is rotatably mounted on the clevis pins 13, with the clevis pins 13 inserted into holes provided in the handle 14 such that the handle 14 is free to rotate. The handle 14 is also provided with a clevis slot 15 that is adapted to receive the T-bar 10 when the clamp 200 is in a closed position. The handle 14 is also provided with an end stop 16adapted to abut one of the clevis plates 11 when the clamp 200 is in an overcentre position. The clevis plates 11 and the handle 14 are also provided with locking holes 17, the purpose of which is described further below.

Figure 2 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in a first installation position. The forward clamp half 3 is offered up to the support structure 18, and the rear clamp half 7 is rotated such that it comes into contact with the support structure 18.

Figure 3 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in a second installation position. At this point the T-bar 10 is received in the clevis slot 15 on the handle 14. The strength of the grip of the forward clamp half 3 and the rear clamp half 7 may be adapted by rotating the T-bar 10 in the trunnion 9 to adjust its length. The shorter the T-bar 10 the greater the grip of the clamp 200 on the support structure 18.

Figure 4 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in the closed position. The handle 14 has been rotated, dragging the T-bar 10 engaged in the clevis slot 15, tightening the forward clamp half 3 and the rear clamp half 4 against the support structure 18 until the clamp 200 is closed. The handle 14 is rotated further until the end stop 16 abuts the clevis plates 11 at which point the clamp 200 is in an overcentre position.

Figure 5 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention with the clamp in an overcentre position with a locking pin inserted. The clamp 200 further comprises a locking pin 19 that is adapted to be inserted into the locking holes 17 when the clamp 200 is in an overcentre position. This acts to protect against inadvertent release of the clamp 200 by locking the clamp 200 in the closed position.

Figure 6 is a perspective view of an overcentre clamped ladder steady in accordance with an embodiment of the present invention installed on a vertical support. A ladder 20 is aligned with the ladder support, and a lashing 22, such as a webbing strap, is applied between the ladder stile 21 and the ladder support 1. The ladder 20 is supported safely at a distance away from the support structure such that tasks can be carried out at height.

Although in the embodiments illustrated the forward clamp half 3 and the rear clamp half 7 are concave, they may be of any other suitable shape depending upon cross-section or construction of the support structure to which they are intended to be clamped. For example, a flat or rectangular clamp half may be used. Materials other than steel may be chosen to form the ladder support 1 and the clamp 200 dependent upon the structural strength required for the intended use of the overcentre clamped ladder support 100.

Another aspect of the present invention provides a method of clamping the overcentre clamped ladder steady 100 described above to a support structure 18. Figure 7 illustrates a method of clamping the overcentre clamped ladder steady to a support structure. In particular, this figure illustrates the steps of locking and unlocking the overcentre clamped ladder steady. At step 300 (as illustrated in Figure 2) the forward clamp half 3 and the rear clamp half 7 around the support structure 18 with the clamp 200 in the open position. At step 302 the T-bar 10 is received in and engaged with the clevis slot 15. At step 304 the handle 14 is rotated towards the rear clamp half 7 to cause the forward clamp half 3 and the rear clamp half 7 to grip around the support structure 18 (as illustrated in Figure 3) until the end stop engages 16 with the clevis plates 11 and the clamp 200 is in an overcentre position (as illustrated in Figure 4). It may be necessary at step 306 to adapt the strength of the grip of the forward clamp half 3 and the rear clamp half V on the support structure 18 by rotating the T-bar 10 within the trunnion 9 to adjust its length. And at step 308 the locking pin 19 is inserted into the locking holes 17 in the clevis plates 11 and the handle 14 to lock the clamp 200 into a closed position. To release the clamp 200, the locking pin 19 is removed from the locking holes 17, the handle 4 is rotated away from the rear clamp half 7 and the T-oar released from the clevis slot 15 -in other words, steps 300 to 308 are reversed, as indicated in Figure 7.

Claims

CLAIMS1. An overcentre clamped ladder steady comprising: An overcentre clamp having an open and a closed position; and A ladder support mounted on the overcentre clamp; wherein The overcentre clamp comprises a forward clamp half having a clamping surface and a rear clamp half having a clamping surface rotatably coupled to one another by a hinge pin; a pair of trunnion plates mounted on the forward clamp half and adapted to hold a trunnion; a T-bar inserted into the trunnion and adapted to be adjustable within the trunnion; a pair of clevis plates mounted on the rear clamp half and adapted to hold a clevis pin; and a handle rotatably mounted on the clevis pin, the handle being provided with a clevis slot adapted to receive the T-bar when the clamp is in a closed position.
2. The overcentre clamped ladder steady of claim 1, wherein the handle is provided with an end stop adapted to abut one of the clevis plates when the clamp is in an overcentre position.
3. The overcentre clamped ladder steady of claim 1 or 2, wherein the clevis plates and the handle are provided with locking holes, and wherein the clamp further comprises a locking pin adapted to be inserted into the locking holes when the clamp is in an overcentre position.
4. The overcentre clamped ladder steady of any of claims 1 to 3, wherein the trunnion comprises a hole having a screw thread and the T-bar is provided with an opposite screw thread such that the T-bar is rotatable in the trunnion to engage the screw threads.
S. The overcentre clamped ladder steady of any preceding claim, wherein the forward clamp half and the rear clamp half are provided with hinge plates, and the hinge pin is inserted into the hinge plates.
6. The overcentre clamped ladder steady of any preceding 5 claim, wherein each of the forward clamp half and the rear clamp half are provided with a resilient material on their clamping surfaces.
7. The overcentre clamped ladder steady of any preceding 10 claim, wherein the ladder support is mounted on the forward half clamp.
8. The overcentre clamped ladder steady of any preceding claim, wherein the clamping surfaces of the forward half 15 clamp and the rear half clamp are concave.
9. The overcentre clamped ladder steady of any preceding claim, wherein the trunnion plates are mounted on the forward clamp half distal from the hinge plates, and wherein the clevis plates are mounted on the rear clamp half distal from the hinge plates.
10. A method of clamping the overcentre clamped ladder steady of any preceding claim to a support structure, comprising: Placing the forward clamp half and the rear clamp half around the support structure with the clamp in the open position; Receiving the T-bar into and engaging the T-bar with the clevis slot; Rotating the handle towards the rear clamp half to cause the forward clamp half and the rear clamp half to grip around the support structure until the end stop engages with the clevis plates and the clamp is in an overcentre position.
11. Method of claim 10, further comprising: Adapting the strength of the grip of the forward clamp half and the rear clamp half on the support structure by rotating the T-bar within the trunnion to adjust its length.II
12. Method of claim 10 or 11, further comprising: Inserting the locking pin into the locking holes in the clevis plates and the handle to lock the clamp into a closed 5 position.