WO2003040512A1

WO2003040512A1 - Safety devices for load bearing members

Info

Publication number: WO2003040512A1
Application number: PCT/GB2002/005003
Authority: WO
Inventors: Michael Carrington
Original assignee: Tigers Paw Ltd
Priority date: 2001-11-06
Filing date: 2002-11-06
Publication date: 2003-05-15
Also published as: GB2381823B; GB0225868D0; GB2381823A; GB0126566D0

Abstract

A safety device comprises a pad with a housing (10), with a perforated end wall (11), through which spikes (13) are extensible by means of load applied via a connection (19), to a moveable plate (15) to which the spikes (13) are mounted, against the bias of a spring (18). The spikes are also individually spring loaded to allow for unevenness in a surface to which the pad is applied. This can be used for example at the top and bottom of ladders to prevent slipping. A sole for footwear is also disclosed with inner and outer soles with a foam layer between and spikes or studs on the inner sole which can be extended through the lower sole when the foam layer is compressed.

Description

SAFETY DEVICES FOR LOAD BEARING MEMBERS

This invention relates to safety devices for ladders and other devices where it is advantageous to prevent slipping of load bearing members on a surface.

For example in the case of ladders, these are usually rested with the lower end directly upon the ground and the other, upper, end is often rested upon a vertical surface such as a wall. A significant number of accidents causing injury arising from the use of ladders are caused by slipping of the ladder where the lower end is insecurely braced, for example by being rested upon a friable or slippery surface. Many other accidents are caused by slipping of the upper end of the ladder upon the wall surface, usually either sideways or downwards.

Similar problems may be encountered on other uses, such as footwear for use for example in hill walking, rock climbing or scrambling, locating equipment on board ships to prevent slipping in heavy sea conditions and in other potentially unstable situations to provide a firm footing, as a rescue aid, and for load carriers and grippers.

It is an object of the invention to provide a safety device which is capable of use to substantially prevent slipping of one part relative to another particularly in situations where a sideways load is applied steadily or transiently.

According to the invention, a safety device comprises a substantially planar pad member for mounting on a moveable member, the pad member being provided with an array of spikes for engagement with a surface upon which the pad is rested under load applied by the moveable member. The spikes may advantageously be at least partially retractable into the pad, and in this case preferably are spring loaded or biased by other resilient means to extend from the pad, so that the spikes are positively engaged with the surface.

The spikes may be at the minimum three in number, preferably in an equilateral triangular array, or any number over three, for example five disposed in a regular pentagonal array. The spikes may be mounted in a freely floating member such as a plate, and the spikes may extend through apertures in a second fixed plate, with resilient means such as springs placed between the floating plate and the fixed plate. The spikes may have conventional pointed ends or may present a chisel edge, but in a preferred embodiment, have a circular tip with a central hollow, presenting a circular edge. These have been found to give a much better grip than ordinary points.

The moveable member may be connected to the floating member, so that the load applied by the moveable member acts to drive the spikes against the surface against the bias of the resilient means. Alternative arrangements of spikes may include rows of parallel spikes, or circular arrays.

In the case of footwear, the fixed member may comprise a lower sole and the floating member in which the spikes are fitted may comprise an innersole, the soles being separated by a^" cushioning layer of for example a foamed plastics material which provides the resilient means. For use on ladders, pads may be provided for use at both the lower and upper ends of the ladder, and have connecting members which can be bolted to the upper and lower ends of the ladder, or secured about respective upper and lower rungs of the ladder. For use in generally securing loads, machinery or the like for example or board ship, pads may be provided which can be secured temporarily to parts of the loads, or to pallets carrying the loads. Pads may also be provided mounted on gripper jaws for load handling. 5 The invention will now be further described with reference to the accompanying drawings which illustrate embodiments of safety device according to the invention in exemplified uses.

In the drawings:-

Fig 1 is a sectional view showing an embodiment of safety device according 10 to the invention.

Figs 2 and 3 illustrate alternative possible embodiments with different numbers of spikes.

Fig 4 is a side elevation of the. fig 2 embodiment of safety device;

Fig 5 is a diagram showing a ladder filled with safety devices according to the 15 invention at each side of the ladder;

Fig 6 shows the lower end of the ladder of fig 5 in more detail;

Fig 7 is a sectional view of a preferred spike tip profile; and

Fig 8 is a sectional view through the sole structure of an item of footwear incorporating a safety device according to the invention. 20. Fig .l is sectional view of a safety device according to the invention which comprises a cylindrical body 10 having a perforated and plate 11 formed integrally herewith or fixed relatively thereto. The end plate 11 is formed with a plurality of holes 12 through which extend an array of spikes 13, in this example well in excess of the three or five spikes shown in Figs 2 and 3. The spikes 13 are seated in a plate assembly, which is moveable relative to the body 10 and is disposed parallel to the end plate 11 and comprises a first plate 14, and an outer plate 15, sandwiched between the plates 14 and 15. Ends 17 of the spikes 13 are located in bores 16 within the inner plate 14. The spikes 13 are each acted upon by a compression spring in the bore 16. The plate 14 is loaded away from the end plate 11 to retract the spikes 13 by a main spring 18.

The plate assembly is connected to a_. bracket 19 which can in turn be connected to a member which applies a load to the plate assembly. The compression springs act to retract the spikes into the body 10 when no load is being applied to the plate assembly, by pushing the plate assembly to the left in Fig 1. The load imposed through the bracket 19 acts to extend the spikes from the housing. To allow for unevenness in the surface to which the device is applied, the bores 16 and individual springs in. the plate .14 .allow, for .-the spikes 13 to-be extended to different lengths,, whilst the ends 17, which are wider than the bores in the plate 14 prevent the spikes from dropping out of the housing.

Fig 2 and 3 show views of two further embodiments of safety device according to the invention from a view point corresponding to the view from the right hand side of Fig 1, and Fig 4 is a side view of the device shown in Fig 2. These embodiments each comprise of body 20, with an internal construction similar to the device of Fig 1, and with a bracket 21 (Fig 4) for attachment to a load member. The body 20 in each case has a plurality of spikes 22 extending therefrom symmetrically disposed, there being three spikes 22 shown in Figs 2 and 4 arranged in an equilateral triangular array and five in Fig 3 arranged at the comers of a regular pentagon. Further, the spikes 21, instead being mutually parallel and parallel to the axis of the body 20, diverge at an angle outwardly from the axis of the body 20 and from each other. This is best shown in Fig 4. The divergence of the spikes aids gripping with a hard or friable surface to increase resistance to slipping under the load applied by the moveable member. Figs 5 and 6 illustrate the safety device of Figs 2 and 3 as in use with a ladder

30. The ladder 30 is shown in Fig 55 with its upper end leaning against a wall 31, and its lower end resting on the ground 32. The upper and lower ends of the ladder are equipped with safety devices 33 according to the invention (not shown to scale in Fig 5) which apply the weight exerted by the ladder 30 against the wall 31 and ground 32 through the devices 33.

Fig 6 shows one method of attaching the safety devices to the foot and correspondingly to the top of the ladder by engaging the ends of the side members 34

* of the ladde-r between -eyed brackets 35 on the bodies of the safety devices by means of bolts 36 extending through the brackets 35 and corresponding bores in the ends of the side members 34 to pivotally on the device 33 on the ladder. An alternative fixing method is to attach the safety devices such as 33 by arms to the uppermost and lowermost rungs 37 of the ladder.

When used for improving the safety of ladders, as in Fig 5 and 6 above, the device allows a high frictional contact to be attained and maintained between each end of the ladder and the horizontal and vertical surfaces even where the latter are friable and slippery, so that security against slipping of the ladder is considerably improved. Fig 7 is a sectional view of a preferred form of spike 22. This has a tip 221, presenting a circular end with a hollow 222 which creates a circular edge 223. This has been found to give improved grip.

The configuration of the spikes may be varied with the intended use and most likely surfaces to the engaged by the device, for example for engagement with turf or grassed areas the spikes may be relatively long, whilst for harder surfaces, the spikes may be shorter and for example of hardened stee

Fig 8 is a diagram showing a cross-section of a sole structure for footwear.

Such footwear may be used for hill walking, rock climbing and scrambling or as trainers or running shoes. The sole structure comprises a relatively rigid inner sole

40, a second relatively rigid lower sole structure 41 which may be configured to provide for example a heel. A resilient springy layer 42 of for example foamed

• elasto εric -material is provided between the relatively rigid inner and lower sole? 40.,

41 and studs or spikes 43 are formed integrally with or seated in the inner sole 40, which extend through bores or voids in the lower sole 41 and the resilient layer 43.

When the weight of a wearer is placed upon the inner sole during walking or the like, the layer 42 is compressed and the spikes or studs 43 are extended out below the lower sole 41. The studs or spikes may be flat, or pointed or otherwise configured to provide a grip on a desired surface, for example relatively short blunt spikes of hard material may be used for climbing shoes to grip on wet rock and friable shale surfaces, whilst longer blunt or pointed spikes may be used for turf as in athletic or training shoes. As a safety feature it is noted that when the wearers' weight, is taken off the sole as the foot is lifted, the spikes are retraced, so that for example in soccer, accidental foot contact with another player is less likely to result in stud related injury.

Claims

1. A safety device comprising a substantially planar pad member for mounting on a moveable member, the pad member being provided with an array of spikes for engagement with a surface upon which the pad is rested under load applied by the moveable member.

2. A device according to claim 1, wherein the spikes are at least partially retractable into the pad and spring loaded or biased to extend from the pad so that the spikes are positively engaged with the surface.

3. A device according to claim 1 or 2 wherein there are at least three spikes and the spikes are arranged in a symmetrical array.

4. A device according to my preceding claim wherein the spikes are mounted in a freely floating member such as a plate and extend through apertures in a second fixed plate, with resilient means placed between the floating plate and the fixed plate.

5. A device according to claim 4 where in the moveable member is connected the floating member so .that the load applied by the moveable member acts to drive the spikes against the surface against the bias of the resilient means.

6. A device according to any preceding claim wherein the pad is connectable to the moveable member by an eyed bracket

7. A device according to any preceding claim adapted to be mounted at each end of a ladder to bear on the ground and a wall or other upright surface at respective ends to reduce the risk of slipping between the ladder and the upright surface or ground.

8. A safety device according to claim 1 configured as a sole structure for an article of footwear comprising an array of studs or spikes mounted on or formed with an inner sole and adapted to be extended through apertures in a lower sole, a resilient layer being provided between the inner and lower soles.

9. A safety device according to claim 4 wherein there are five spikes disposed at the angles of a regular pentagon.

10. A safety device according to claim 9 wherein the spikes are inclined and directed away from each other and the axis of the pad.

11. A safety device wherein the spikes each have an end profile comprising a circular rim or edge with a central hollow.