GB2459118A

GB2459118A - Ladder clamp

Info

Publication number: GB2459118A
Application number: GB0806525A
Authority: GB
Inventors: Christopher Neil
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-04-10
Filing date: 2008-04-10
Publication date: 2009-10-14
Also published as: GB0806525D0

Abstract

The present invention relates to a pair of clamps 2 mounted to a ladder 4 to secure the ladder to a member i.e. a scaffolding tube. The clamps comprise a securing arrangement including first and second jaw portions 12 and 14. The first upper jaw portion 12 is moveable between an open and a closed configuration on insertion of the scaffold tube into the mouth defined between the first and second jaw portions. The second lower jaw portion 14 is mounted relative to the securing arrangement and is rotatable between a release configuration and a locked arrangement. The securing arrangement may comprise a biasing means (30 figure 4) to bias the second jaw portion in the open configuration. The second jaw portion may be locked in the closed position by means of a pawl (38 figure 4) and tooth (43 figure 4) engaging with teeth (44 figure 4) of the lower jaw portion.

Description

Ladder Clamp The present invention relates to an apparatus for releasably securing a ladder to a member.

In particular, the apparatus may be used for releaseably securing a ladder to a member such as scaffolding.

Scaffolding is commonly used to enable work to be carried out on, for example a building at heights which are impossible to reach from the ground. Accordingly, scaffolding is built around the object to be built or which requires maintenance and is made secure such that a wide variety of operations can be carried out whilst being supported by this scaffolding.

Problems are faced when a user must climb onto the scaffolding. Ladders are commonly used and may be leaned against the scaffolding, however this is clearly not safe with a high probability of the ladder moving and as such a rope is commonly used to tie the ladder onto the scaffolding to prevent the ladder form slipping or falling. Alternatively, a mechanical cormection mechanism may be utilised. However, there are safety problems associated with fixing such mechanism or rope as the first person to climb the ladder will clearly not benefit from the safety effect of the ladder being affixed onto the scaffolding.

Additionally, the security of the ladder against the scaffolding will be dependent on the quality of the fixing or knot that has been tied.

: The present invention provides a significantly improved arrangement.

According to the present invention there is an apparatus for securing a ladder to a member, S.....

* the apparatus comprising a securing arrangement including first and second jaw portions, * 25 the first jaw portion moveable between an open configuration for receiving a member and a closed configuration for preventing release of the member, the first jaw portion moveable between the open and the closed configuration on insertion of the member into the mouth defined between the first and second jaw portion.

Benefits of such an arrangement are significant and enables a user to fix the apparatus onto any ladder. Furthermore, the ladder can then be raised to locate onto the necessary scaffolding and the apparatus can lock to prevent release of the ladder from the scaffolding.

The securing arrangement preferably further comprising a locking arrangement operable to lock the first jaw portion in the closed configuration, and beneficially a body portion for retaining the securing arrangement, wherein the securing arrangement is moveable relative to the body portion to cause release of the locking arrangement.

When release of the ladder from the scaffolding is required, movement of the ladder will cause the apparatus to unlock, in both cases with the user safely on the ground.

The securing arrangement is preferably slidably engaged with a body portion, the securing arrangement moveable between a locked configuration and a release configuration.

A biasing means is further provided connectable between the securing arrangement and the body portion, arranged to bias the securing arrangement to a released configuration. In use this is important to prevent accidental clamping of the apparatus in the incorrect * ..* configuration. Once clamped onto the scaffolding, the weight of the ladder pulling down on the apparatus causes the biasing means to extend. S... *...

The securing arrangement preferably comprises a plurality of protruding members * arranged to locate within corresponding receiving portions of the body portion. The * securing arrangement is therefore prevented from release from the body portion.

S. SSSS * * * S.....

* 25 The first jaw portion is preferably rotatably mounted relative to the securing arrangement, rotatable between a release configuration and a locked configuration. Even more beneficially, the first jaw portion is preferably pivotally mounted relative to the securing arrangement. The first jaw portion is therefore rotatable relative to the second jaw portion.

The securing arrangement preferably further comprises a biasing means arranged to bias the first jaw portion to an open configuration. This ensures that the apparatus is primed ready for receipt of a scaffolding member for subsequent locking.

The locking arrangement preferably comprises a retaining member arranged to communicate with the first jaw portion to retain the first jaw portion in the locked configuration. The first jaw portion beneficially comprises a plurality of teeth thereon arranged to communicate with the retaining member to cause locking of the first jaw portion in the locked configuration. Rotation of the first jaw portion to the locked configuration therefore prevents the first jaw portion from accidental release and beneficially a number of teeth are provided such that scaffolding of varying diameters or shapes can be clamped.

The second jaw portion and the securing arrangement preferably defines a mouth into which the member onto which the apparatus is secured locates, the first jaw portion having a first end configured to communicate with the member and thus cause rotation of the first jaw portion to a locked configuration, and a second end of the first jaw portion in the locked configuration arranged to prevent release of the member from the mouth.

The locking arrangement preferably further comprises a biasing means arranged to bias the *.*. ** retaining member to a locked configuration. This ensures that the retaining member cannot accidentally release from the first jaw portion thereby accidentally releasing the ladder S...

from the scaffolding.

* The retaining member is preferably arranged to communicate with the body portion, such that movement of the securing arrangement between the locked configuration and release * configuration causes interaction of the retaining member and body portion thereby causing S.....

* 25 release of the retaining member from the first jaw portion. This is important in the release operation and as described in detail later on may be provided by the retaining member extending through an aperture in the body portion. Once a predetermined amount of movement has occurred between the securing arrangement with respect to the body portion, interaction of the retaining member and body portion occurs and as such release is achieved. Some movement of the securing arrangement with respect to the body portion is allowed as in actual use a small amount will occur naturally which does not warrant release of the securing arrangement from the scaffolding.

The present invention also extends to an arrangement that can be used for securing two ladder sections together. Commonly used ladder sections are held together by a simple hook located on the upper ladder section which hook over the runs of the bottom ladder section whilst a guide at the upper end of the bottom section maintains the two sections together. The length of the ladder can then be adjusted depending on specific requirements. A problem, however, with such an arrangement is that the hook over the runs of the ladder can be accidentally removed. This provides a danger to a user.

Accordingly, it is beneficial to provide a clamping arrangement which ensures that accidental release cannot occur.

The mounting arrangement enables the apparatus to be secured to the top ladder section.

The securing arrangement includes first and second jaw portions defining a mouth therebetween. The first and second jaw portions are moveable between an open configuration for receiving a member and a closed configuration for preventing release of the member. The first and second jaw portions are rotatably mounted onto a frame portion extending from the mounting arrangement. Means is provided to secure the first and ***., second jaw portions in a closed configuration. A biasing means is arranged to bias the first and second jaw portions to an open configuration. S... S...

The body portion is preferably mountable onto a ladder, however alternatively a ladder * may be provided comprising a securing arrangement as hereinbefore described.

I

*..S..

* The present invention will now be described by way of example only with reference to the S*.

* 25 accompanying drawings in which: Figures 1 and 2 are schematic perspective views of a pair of clamps located on a ladder according to an exemplary embodiment of the present invention.

Figure 3 is an exploded view of a clamp according to an exemplary embodiment of the present invention in a first open configuration.

Figure 4 has a very schematic perspective view of the clamp in a first open configuration showing the entire assembly.

Figure 5 is a schematic exploded view of the clamp in the closed configuration according to an exemplary embodiment of the present invention.

Figure 6 is a schematic perspective view of the clamp according to an exemplary embodiment of the present invention in the second closed configuration.

Figure 7 is a schematic side view of an alternative exemplary embodiment of the present invention showing two ladder sections releaseably connected together.

Referring to Figures 1 and 2, a pair of clamps 2 are mounted onto a ladder 4. The clamps 2 are beneficially releasable from the ladder 4 and as such a clamping mechanism is necessary to ensure that the clamp 2 is fixedly mounted onto the ladder 4. It will be appreciated that in an alternative embodiment the clamps 2 may be integrally mounted or manufactured with a ladder 4. * ** * * * * **

The clamping mechanism by which the clamp is connected to the ladder 4 generally comprises a pair of parallel plates 6 shown more clearly in Figure 2. These parallel plates **** locate either side of the longitudinal members of the ladder 4. A lip portion 8 beneficially * extends perpendicular to the plane of the plate arranged to communicate with the lips generally found on a ladder 4. A plate 6 and corresponding lip portion is located either S. e*S.

* side of the longitudinal member of the ladder and a clamp mounting plate 10 is arranged to *S.SSS * 25 locate over the longitudinal rim of the ladder 4 and releasably mount relative to the plates 6. Means are provided to fix the clamp mounting plate 10 to the lip portion 8 of the plate 6. Any suitable clamp means may be provided such as a nut and bolt. It will be appreciated from the Figures that an elongate slot may be provided within the clamp mounting plate 10 and the lip portion 8 of the plate 6 such that adjustability is provided depending on the width of the elongate member of the ladder. Further additional means may be provided for fixing the plates and clamp mounting plate 10 onto the ladder for example, by providing apertures through the plate 6 and longitudinally through the elongate members of the ladder such that further nut and bolt type fixing arrangements may be utlised. Additionally or alternatively, instead of nut and bolt type clamping arrangements, quick release arrangements may be provided which would enable quick release of the clamp 2 to be located onto another ladder, as required, or adjust to the correct height along the longitudinal length of the ladder as necessary.

The clamp comprises a first jaw portion 12 which will be termed the upper jaw and a second jaw portion 14 termed the lower jaw.

Referring to Figures 3 and 4, an exploded view of the assembly is schematically represented in Figure 3 and a full assembly showing the internal workings of the arrangement is schematically represented in Figure 4. The assembly, as described above, can be mounted onto a ladder or formed integrally with a ladder. The clamp mounting plate 10, which is arranged to mount onto the ladder comprises a frame 16 defining a channel in which the clamping mechanism is arranged to locate. The upper jaw 12 in the specific embodiment described herein includes a first locking pin 18 extending perpendicular to the upper jaw 12 which is arranged to locate in an aperture 20 of the frame 16. Movement of the upper jaw 12 with respect to the frame 16 is therefore allowed within the aperture 20. It will be appreciated that the frame 16 has a further aperture 20 on the opposing side and the locking pin 18 extends through this aperture 20 in the same 0*I* manner as indicated on Figure 4. For ease of assembly, the upper jaw 12 may comprise a laminate structure whereby a first plate 22 and a second plate 24 sandwich the upper jaw 12 there between and may form part of the jaw itself as indicated with particular reference to Figure 4. The other aspects of the clamping mechanism itself may therefore be formed S.* I 25 within the confines of the first and second plate 22, 24 respectively.

The lower jaw 14 comprises a cam which is arranged to rotate about a pivot point 25, the pivot point 25 being seated between the first and second plate 22, 24. The lower jaw is shaped and configured to have a clamping portion 26 and an engaging portion 28 which will be described in more detail with respect to the functioning of the clamp. A spring 30 is provided which connects to the lower jaw 14 at one end and lower portion 32 extending between the first and second plates 22, 24. The spring is arranged to bias the lower jaw 14 in a clockwise rotation about pivot point 25 such that on rotation of the lower jaw 14 anticlockwise as the clamp comes into contact with a scaffolding for example, rotation of the lower jaw 14 is against spring 30. The lower portion 32 further comprises a locking pin 34 which locates within an aperture 36 located within the first and second plate 22, 24 respectively. It will therefore be appreciated that the components formed between the first and second plate 22, 24 can all move within the confines of the apertures 20 and 36. A further feature of the clamp is a pawl 38 which is pivotally mounted about pivot point 40 within first and second plates 22, 24. The pawl 38 comprises a tooth 42 which is arranged to engage with teeth 44 formed on the lower jaw 14. Interaction of the tooth 42 and teeth 44 prevents rotation of the lower jaw 14 in certain specific configurations. The pawl 38 has a spring 46 mounted at one end which connects to the lower portion 32. It will also be appreciated that there is an aperture provided within the clamp mounting plate 10 through which a portion of the pawl 38 extends. The purpose of this aperture 48 will be described with specific reference to the functioning of the arrangement.

A further spring 50 is mounted between the lower portion 32 and the frame 16. The spring is configured to be extended when the arrangement defined between the first and second plates move in a generally upward direction relative to the frame 16. * ** * * **.

The application of the present invention will now be described wherein the arrangement is *.S.

dSP: fixedly connected to a ladder and the ladder is to be connected to a scaffolding bar. It will * be appreciated that the ladder may be releasably clamped to a scaffolding structure which provides a significant benefit in terms of the safety of the user as the clamp cannot *, I..S * accidentally release from the scaffolding without the user climbing off the ladder and *..*S1 * 25 carrying out the specific removal steps.

The arrangement is initially in the configuration as indicated in Figures 3 and 4 fixedly connected to a ladder. The ladder is manoeuvred such that the scaffolding bar onto which the ladder is chosen to clamp locates into the mouth defined between the upper jaw 12 and the protruding portion of the first and second plate 22, 24. This protruding portion of the first and second plate 22, 24, designated with reference numeral 52, may be shaped such that entry into the mouth defined between the upper jaw 12 and the protruding portion 52 is made as easy as possible. This may be achieved through the provision of a curved engaging ramp in an alternative to the protruding portion 52 as indicated in Figure 4. As the scaffolding bar contacts the engaging portion 28 of the lower jaw 14, there is an associated force against the engaging portion 28 which causes rotation about pivot point 25 and furthermore causes a subsequent pivoting of the pawl 38 and as such the tooth 42 of paw! 38 engages with the teeth 44 of the lower jaw 14. Rotation back in a clockwise direction is therefore prevented. As rotation of the lower jaw 14 in an anti clockwise direction occurs, the clamping portion 26 rises from the confines of the first and second plate 22, 24 thereby preventing release of the scaffolding bar from the mouth defined now between the lower jaw 14 and the upper jaw 12. As engagement of the scaffolding bar occurs, there is additionally movement of the clamp anangement with respect to the frame 16 against the spring 50. The weight of the ladder including the clamp 2 causes this relative movement which then reaches the configuration as indicated in Figures 5 and 6, in exploded view and complete assembly. In this configuration, spring 50 and spring 30 are both in an extended configuration, spring 50 acting to pull the clamp located within the frame 16 downward to its natural rest configuration and spring 30 acting to try and rotate the lower jaw 14 in a clockwise direction. However, this is prevented through the action of the tooth 42 of the pawl 38 against the teeth 44 of the lower jaw 14. * .. * * * * **

***.* 20 Once the clamp is in the locked configuration, release is impossible whilst a user is on the ladder. Release may only occur when a user climbs off the ladder and actively takes the *..: necessary steps to unlock from the scaffolding bar. A user pushes up the ladder assembly * which causes movement of the clamp assembly defined within the first and second plate 22, 24 within the frame 16. As the ladder is pushed further upwards an increased force is ** **..

* 25 placed on the spring 50 causing extension of this spring. As further movement of the ****** * locking ends 18, 34 through the apertures 20, 36 in a generally downward direction occurs, this has the effects of also moving the pawl 38. The pawl 38 comprises a portion which extends through an aperture 48 located in the clamp mounting plate. This portion of the pawl 38, after a predetermined degree of movement will come into contact with the lower end of the aperture 48 and thus be prevented from further movement. The spring 46 extends in an attempt to draw paw! 38 back, however, this is prevented by the edge of the aperture 48 in the clamp mounting plate 10. Accordingly, the tooth 42 of the paw! 38 disengages with the teeth 44 which thereby allows the spring 30 to rotate the lower jaw 14 in a clockwise direction, therefore bringing the clamp arrangement defined within the plates 22, 24 to a rest open configuration. The arrangement is withdrawn from the scaffolding and release is therefore enabled. The arrangement can then be repositioned on another scaffolding component as necessary.

In order to prevent accidental release of the clamp from the scaffolding on minor movement of the ladder, some play is allowed in the system. This is achieved by ensuring that the ladder has to be pushed upwards a predetermined distance before release is achieved. This is accommodated by providing a suitable size aperture wherein a predetermined distance must be overcome before the pawl 38 will engage with the lower edge of the aperture 48 thus causing disengagement of the pawl 38 from the lowered jaw 14.

Referring to Figure 7, there is a schematic side view of a mechanism suitable for releasably connecting a top ladder section 102 to a bottom ladder section 104. Prior art arrangements usually include a hook fixedly connected to the top ladder section which is arranged to hook over the rungs 106 of the bottom ladder section 104. However, there are safety issues *: * : :* with such an arrangement that accidental release can occur. Accordingly, the arrangements *.... 20 are schematically represented in Figure 7 overcomes this problem.

: A frame portion 108 is fixedly connected to the top ladder section via any known arrangements such as a nut and bolt mechanism 110. The frame portion 108 extends away from the top ladder section and includes a connecting portion 112 which is configured to * S...

* 25 be suitable for attaching to the rung 106 of the bottom ladder section 104. The connecting S.....

* S portion 112 is pivotally mounted via pivot point 114. The connecting portion 112 is therefore rotatable about pivot point 114 and in a rest configuration sits in an open configuration not shown in Figure 7 ready to contact the rung 106 of the bottom ladder section 104. The connecting portion 112 is biased to an open configuration via a spring 116. In use, the mouth 118 of the connecting portion 112 contacts the upper portion of the rung 106 which cause rotation about pivot point 114 and thus extends spring 116 moving into the configuration which is closed as indicated in Figure 7. In this configuration it would be appreciated that a jaw portion defining the mouth 118 locates underneath the rung 106 and can prevent release. However, a catch mechanism 120 is provided to prevent rotation of the connecting portion back to the open configuration. Any suitable catch mechanism may be provided however as indicated in Figure 7 a simple spring loaded bolt is provided which includes a bolt 112 which communicates with a recess in the connecting portion 112 therefore preventing the connecting portion 112 from accidental release.

The mechanism as described with respect to Figure 7 is advantageous as it means the top ladder section and bottom ladder section cannot accidentally release without a user releasing the catch mechanism 120, in the embodiment shown meaning releasing the spring loaded bolt.

It will be appreciated by a person skilled in the art that modifications and variations may be made to the present invention without departing from the scope of protection afforded by the dependent claims. Examples of such alternatives may be that the arrangement is constructed of a polymeric material or for example a fibrous material such as a carbon fibre matrix. This is allowed for simplified manufacturing through, for example, injection moulding. Alternatively, the arrangement may be made of a metallic material having a * *** suitable combination of weight, strength and costs. Furthermore, the first and second plates 22, 24 may not essentially be provided and the assembly may be made potentially **** via a single piece. **** * * *.S * * *

S

***SSS * S

Claims

Claims 1. An apparatus for securing a ladder to a member, the apparatus comprising a securing arrangement including first and second jaw portions, the first jaw portion moveable between an open configuration for receiving a member and a closed configuration for preventing release of the member, the first jaw portion moveable between the open and the closed configuration on insertion of the member into the mouth defined between the first and second jaw portion.
2. An apparatus according to claim 1 wherein the securing arrangement further comprises a locking arrangement operable to lock the first jaw portion in the closed configuration.
3. An apparatus according to any of claims 1-2 further comprising a body portion for retaining the securing arrangement wherein the securing arrangement is moveable relative to the body portion to cause release of the locking arrangement. * S. * S * * S**....* 20
4. An apparatus according to claim 1 wherein the securing arrangement is *SS* slideably engaged with the body portion, the securing arrangement moveable S...

* between a locked configuration and a release configuration.
5. An apparatus according to claim 3 further comprising a biasing means ** *S.* * 25 connectable between the securing arrangement and the body portion arranged *...** * S to bias the securing arrangement to a release configuration.
6. An apparatus according to any of claims 3-5 wherein the securing arrangement comprises a plurality of protruding members arranged to locate within corresponding receiving portions of the body portion.
7. An apparatus according to any preceding claim wherein the first jaw portion is rotatably mounted relative to the securing arrangement, rotatable between a release configuration and a locked configuration.
8. An apparatus according to claim 7 wherein the first jaw portion is pivotally mounted relative to the securing arrangement.
9. An apparatus according to any of claims 7-8 wherein the securing arrangement further comprises a biasing means arranged to bias the first jaw portion to be an open configuration.
10. An apparatus according to any preceding claim wherein the locking arrangement comprises a retaining member arranged to communicate with the first jaw portion to retain the first jaw portion in the locked configuration.
11. An apparatus according to claim 10 wherein the first jaw portion comprises a plurality of teeth thereon arranged to communicate with the retaining member to cause locking of the first jaw portion in the locked configuration. * ** * * * * S.*.*. 20
12. An apparatus according to any preceding claim wherein the second jaw * *** portion and the securing arrangement define a mouth into which the member I...

: onto which the apparatus is secured locates, the first jaw portion having a first * end to communicate with the member and thus cause rotation of the first jaw portion to a locked configuration, a second end of the first jaw portion in the ** **** * : 25 locked configuration arranged to prevent release of the member from the * mouth.
13. An apparatus according to claim 10 wherein the locking arrangement further comprises a biasing means arranged to bias the retaining member to a locked configuration.
14. An apparatus according to claim 10 wherein the retaining member is arranged to communicate with the body portion, such that movement of the securing arrangement between the locked configuration and release configuration causes interaction of the retaining member and body portion thereby causing release of retaining member from the first jaw portion.
15. An apparatus according to any preceding claim wherein the body portion is mountable onto a ladder.
16. A ladder comprising an apparatus for securing a ladder to a member, the apparatus comprising a securing arrangement including first and second jaw portions, the first jaw portion moveable between an open configuration for receiving the member and a closed configuration for preventing release of the member.
17. An apparatus as hereinbefore described with reference to the accompanying drawings. * ** * * S * S* * S S... *.S. *.S.S S..SI 5SS*S * .S* *.*.* * S