GB2158540A

GB2158540A - Climbing device for mountaineers

Info

Publication number: GB2158540A
Application number: GB08511389A
Authority: GB
Inventors: Bernt Prause
Original assignee: Edelmann & Ridder & Co GmbH
Current assignee: Edelmann & Ridder & Co GmbH
Priority date: 1984-05-05
Filing date: 1985-05-03
Publication date: 1985-11-13
Also published as: GB8511389D0; ES295834Y; DE3416623A1; ES295834U; FR2563740A1; GB2158540B

Abstract

The climbing device for mountaineers serves for the releasable clamping in a rock crevice, rock fissure or the like. It consists of a support rod (2) and of a pivot pin (4) located at one of its ends (3) with a clamping plate (1) arranged eccentrically thereon, which is able to swing about the pivot pin axis (15). The clamping plate (1) can be forced in the direction of its clamping position and moved in the opposite direction by way of an actuating member (5) guided on the support rod (2). In order to ensure the possibility of using the climbing device even under the most unfavourable conditions and in order to reduce the load on the pivot pin (4) to a minimum, it is provided to give each clamping plate (1) opposite contact surfaces (21,22) on the end face, which are constructed as substantially identical curved sections. Each clamping plate (1) bears by two curved sections on the opposite walls (19) of a rock crevice and in its clamping position ensures a reliable hold, without the clamping forces acting on the pivot pin <IMAGE>

Description

SPECIFICATION Climbing device for mountaineers The invention relates to a climbing device for mountaineers, for releasable clamping in a rock fissure, crevice or the like comprising a clamping plate on a pivot pin located at one end of a support rod, an actuating member which is guided on the support rod being operable to pivot the plate about the pin away from the clamping position.

A climbing device of this type is known from German GM 78 16 861. On each side of the pivot pin passing through the support rod, two eccentrics, able to move in opposite directions to each other, are provided as clamping plates, in which case each eccentric bears solely against one of the opposing side walls of a crevice. A pair of eccentrics supported on the opposing walls of a rock crevice therefore comprises on one side adjacent planes of the application of force, so that an unfavourable moment curve occurs with regard to the clamping forces and tensile forces occurring.

Therefore, two forces lying at a distance apart act on the pivot pin on each side of the support rod, so that the pivot pin is subjected to correspondingly great stress. In order to withstand these loads and in order to guarantee adequate safety, the pivot pin must have very large dimensions. Furthermore, the eccentric discs which are able to move in opposite directions, produce a system which is mechanically uncertain, which again causes an unfavourable load on the pivot pin.

The danger also exists that with correspondingly constructed rock crevices - open on one side or where the crevice is insufficiently deep - on account of its projecting construction, the clamping device cannot be introduced sufficiently deeply into the crevice, so that only one of the two pairs of eccentrics movable in opposite directions can be effective. Since the eccentrics of the pair of eccentrics also lie at a distance apart, on account of the existing level arm, this may either lead to the failure of the device, because clamping in the crevice is impossible, or a tilting moment occurs, which after initial clamping - may lead to the climbing device being torn out under load.

The known climbing device also has the drawback that under certain circumstances it can no longer be removed from its clamping position in a crevice or the like. If a load is applied to or removed from the support rod or if the clamping device is moved slightly in its clamping position by the cable by way of the support rod, then the clamping plates which are able to move in opposite directions to each other tend to be drawn in or to travel into the crevice or fissure, so that a free swinging path is no longer provided for the removal, i.e. for the return of the clamping plates to their inoperative position. A device which is securely clamped in this way can then only be removed with difficulty or even not at all from its clamped position in the crevice or fissure.

The danger also exists that when inserted in a crevice, the eccentrics of the known device pass their limit or contact point and pass by way of their inoperative position into a positon from which they can no longer be returned into a clamping position. This drawback exists in particular at the time of introduction into very narrow crevices, in which the frictional forces occurring at the time of placing, which are produced in particular due to unevenness in the crevice or fissure, tilt the eccentric beyond its inoperative position.

A particularly serious drawback consists in that the known device operates with adequate safety solely up to a clamping position in which the angle of the connecting lines between the point of engagement on the eccentric and the pivot pin axis of the device with the longitudinal axis of the support rod amounts to a maximum of 78 . As soon as this spreading angle is greater than 78 , but in particular when the device is used in an extreme position with an angle of 90 , the device can no longer guarantee a secure hold.In positions beyond 78 the axially aligned stop pins provided on the inner side of the clamping plates for limiting the swinging movement, lie one against the other, due to which they are loaded in shear when a load is applied to the climbing device and they may easily break off, so that the clamping effect is lost. The known climbing device is therefore not suitable for every application. In addition, in practice, the limit value of 78 can only be estimated with difficulty, so that in practice there is always an instability factor. This danger is particularly great when the device is used in a crevice with unsound rock walls. If the rock walls give, the eccentrics move and increase their spreading angle to or beyond the dangerous angle of 78 , which leads to the mountaineer being placed in considerable danger.

In addition, since the climbing device consists of numerous individual parts, it is susceptible to trouble, expensive and relatively heavy. In addition, its manufacture requires a certain accuracy, since the stop pins limiting the two eccentrics which are able to move in opposite directions to each other in their end positions, must be inserted accurately.

In addition, a further functional drawback of the known device consists in that in an inclined or horizontal working position of the device - such as occurs for example when used in transverse fissures or transverse crevices or in clay holes - the force application point of the load at the outer end of the support rod leads to an unfavourabley long lever arm, due to which the support rod is loaded with a considerable bending moment. The danger therefore exists that the support rod may bend, and/or its pivotable connection to the pivot pin breaks or bends, so that the device can drop out.

The device known from US PS 3 877 679 is not able to obviate the aforementioned drawbacks.

It is the object of the invention to develop a climbing device of the aforementioned type so that with a simple and lightweight construction, a virtually unlimited application, in particular with regard to the limitation of the spreading angle, is provided and the loads occurring are reduced to a minimum.

This object is achieved by the characterising fea tures of Claim 1. Since the clamping forces acting between two walls act on one and the same clamping plate, the pivot pin of the device is not loaded by transverse forces occurring as a result of the clamping forces. Only the clamping itself has to absorb the clamping forces, so that the pivot pin of the device is only subject to the tensile forces exerted on the support rod. This results in a high load-carrying capacity of the device, since the clamping plate alone can be designed and given dimensions to correspond to the transverse forces to be received. On account of the few component parts, in addition to a small overall size, simple construction and thus related high operational reliability, a considerable saving of weight is achieved.

Due to a congruent construction of the curve sections of the clamping plate arranged with mirror symmetry with respect to each other, reliable clamping in a crevice is also achieved. In particular, the curve sections of a clamping plate lying opposite each other on the end face are constructed and arranged so that in a clamping position in a crevice with side walls lying parallel to each other, the contact points of the curve sections have the same curve coordinates.

In an advantageous development of the invention, one curve section of the clamping plate is constructed to be profiled, preferably toothed, whereas the curve section of the same clamping plate lying opposite on the end face is constructed to be smooth. Since the clamping plate bearing against both walls of a crevice is mounted eccentrically on the pivot pin, in the clamping position of the device, the support rod lies outside the centre of the crevice close to one wall of the crevice. The clamping plate is thus located on the pivot pin approximately in its lower half in the region of lesser inclination of the smooth curve section, so that the profiled curve section is at a greater distance from the pivot point of the clamping plate than the smooth curve section.When a load is applied to the support rod, the clamping plate carries out a quasirotation into the final clamping position, in which case gentle sliding is ensured due to the smooth curve section and the device is prevented from sliding out of the crevice due to the profiled curve section. In this way an absolutely tight fit is guaranteed. If the rock walls give for any reason, then due to the shape of the curve sections, gentle sliding and tightening is ensured without any jerky or sudden giving for the mountaineer. Due to the profiled curve section, it is also ensured that intended increased friction and a definite engagement point is provided in the clamping position, due to which a defined point of rotation, which is not variable in its engagement position, is ensured.

Furthermore, due to the connecting members from the actuating member to the clamping plates, which lie in front of the support rod, it is made possible for the opening in the support rod provided for the attachment of a rope, to be located between the pivot pin and the actuating member.

This opening is preferably located directly above the upper inoperative position of the actuating member. This has the advantage that when the device is used obliquely or horizontally, the lever arm loading the pivot pin is substantially shorter than in known constructions. The risk of damage to the climbing device is therefore largely reduced.

Further features of the invention will become apparent from the Claims description and drawings, which show embodiments of the invention and are described in detail hereafter: Figure 1 is a front view of a climbing device according to the invention with leg springs located between the clamping plates and the support rod, Figure 2 is a side view of the climbing device according to Figure 1 without the leg springs being shown, Figure 3 is a plan view of a climbing device according to Figure 2, Figures 4a to 4c are side views of the climbing device according to the invention in different clamping positions in crevices with parallel side walls, Figure 5 is a front view of a further embodiment of a climbing device according to the invention, Figure 6 is a side view of a third embodiment of the invention with a support rod composed of two flat sections and a clamping plate, Figure 7 is a front view of a climbing device according to Figure 6, with the leg springs ommitted, Figure 8 is a front view of an embodiment according to Figure 7 with two clamping plates arranged outside the flat sections and with the leg springs shown.

The climbing device according to Figures 1 to 3 consists of a support rod 2, at one end 3 of which two clamping plates 1 are located by means of a spindle, a screw bolt, a pivot pin 4 or the like. The clamping plates 1 have an approximately rectangular basic shape and lie approximately parallel to the planes defined by the broad sides of the support rod 2, in which case the pivot pin 4 passes perpendicularly through the broad sides of the support rod 2 of square cross section. The clamping plates 1 of identical constructier lie in a congruent manner with respect to each other in side view (seen in the direction of the pivot pin axis 15), in which case the pivot pin 4 passes through the clamping plates 1 approximately in a lower corner region, which will be described in detail hereafter.

The clamping plates 1 mounted to swing about the pivot pin axis 15 in the same direction of rotation are held on the pivot pin 4 so that they cannot be lost by locking cotter pins 9.

Provided between each cotter pin 9 and the clamping plate 1 as well as the end 3 of the support rod 2 and the clamping plate 1 is a washer 6, in order that the clamping plates 1 are able to move easily without great frictional losses.

Each clamping plate 1 is connected by way of a rigid connecting member 10 to an actuating member 5, which in the embodiment illustrated is guided on the support rod 2 and surrounds the latter. The lower section of the support rod 2 can be covered with a shrinkable sheath 8.

The actuating member 5 comprises two arms 16, extending parallel to the axis 15, which are each preferably positively connected to a connecting member 10. In the embodiment, in plan view (Figure 1) the actuating member 5 is an approximately rectangular sectional member, in which case each arm 16 comprises two openings lying one behind the other in the longitudinal direction of one arm.

Engaging in the opening in each arm 16 lying closest to the support rod is one end of the connecting member 10, which is preferably formed from spring steel wire having a diameter of approximately imam. The other end 17 of the spring steel wire is bent and engages from the inside in a corresponding housing in the clamping plate 1. This housing in the clamping plate 1 lies approximately diagonally opposite the pivot pin axis 15 (swinging axis of the clamping plate); the swinging axis of the clamping plate lies in one of its lower corners and the connecting member 10 engages the corner of the clamping plate lying diagonally opposite this corner. Furthermore, the connecting member 10 always extends i.e. in every swinging position of the clamping plate 1 or of the actuating member 5 in side view (Figure 2), in front of the support rod 2.

Thus, the connecting members 10 respectively extend close to the planes defined by the broad sides of the support rod 2.

Arranged respectively between the clamping plates 1 and the support rod 2 is a leg spring 7, which is located approximately coaxially with respect to the pivot pin axis 15. A first leg of the spring 7 thus engages on the support rod 2 and a second leg engages on the inside of each clamping plate 1 so that by way of the connecting members 10 the actuating member 5 is forced in the direction of the swivel axis 15 and bears against a stop pin 12 limiting the displacement, which corresponds to the upper inoperative position of the actuating member 5 (Figure 1).

By means of these leg springs 7, the clamping plates 1 are forced independently of each other into their clamping position. In this case, clamping position means the position of the clamping plates in which the distance measured at right angles to the longitudinal axis of the support rod, of their contact faces constructed as curve sections 21, 22 from the pivot pin axis 15 is greatest. In the inoperative position of the clamping plates 1, this distance is at its smallest.

The clamping plates 1 are constructed according to the invention so that a clamping plate 1 in a clamping position bears by its two contact surfaces 21 and 22 on the end faces against the opposing walls 19 of a crevice, fissure or the like, opening or recess in a rock wall and can thus be clamped securely between these two rock walls 19 (Figures 4a to 4c). The contact surfaces of a clamping plate 1 are thus constructed as curve sections, in which case at least one curve section is discontinuous.

However, the curve sections are preferably curves corresponding exactly to each other geometrically, i.e. congruent curve sections, which are constructed as involutes, cycloids, orthocycloids or similar geometrical curves. The clamping plate is thus preferably constructed with mirror symmetry.

The curve section 21 thus corresponds to the curve section 22 reflected at the mirror point 20, in which case the mirror point corresponds to the central point of the clamping plate 1 (Figure 2). Therefore, the clamping plate 1 could also be referred to as double involutes, double cycloids etc.

On account of the aforedescribed eccentric mounting of the clamping plate 1 on the pivot pin 4, the curve section 21 is at a greater distance from the pivot pin axis 15 than the curve section 22. In a further development of the invention it is provided to construct the curve section 21 (contact surface) which is further from the pivot pin axis 15 in a profiled manner, preferably to provide it with a toothed profile. On the other hand, the curve section 22 (contact surface) lying opposite the profiled curve section 21 is constructed to be smooth, due to which reliable clamping is guaranteed. In this case, each clamping plate is mounted approximately in its lower half in the region of lesser inclination of the curve section 22 with the smooth end face on the pivot pin 4. Both clamping plates 1 dre always swung jointly in the same direction.

The curve sections of the opposing end faces of each clamping plate 1 are arranged and constructed so that in a clamping position according to Figures 4a to 4c in a crevice with parallel side walls 19, the contact joints 23 and 24 on both sides lie such that - with respect to the curve sections they have the same curve coordinates with the same inclination. The connecting line 25 between the contact points 23 and 24 thus always lies at an angle (x of approximately 7" to 16 with respect to the horizontal.

In the climbing device provided in this embodiment with two clamping plates - in order to achieve the effect according to the invention, the arrangement of a clamping plate for example in a fork at one end of the support rod is adequate - by displacing the actuating member 5 in the direction of the lower end 18 of the support rod, both clamping plates are moved jointly into their inoperative position, in order to introduce the climbing device into a rock crevice, in which case the two curve sections 21 and 22 at the end faces of a clamping plate 1 are aligned respectively in the direction of one wall 19 of the rock crevice.After releasing the actuating lever 5, the force of the leg springs 7 will bring the clamping plates 1 respectively into abutment against the walls 19 (see Figure 4b), so that in this clamping position, each clamping plate bears by its curve sections 21 and 22 against the walls 19. The support rod is swung by the reaction force of the leg springs up to a wall 19, against which it bears by its lower end 18 (Figure 4a), due to which the climbing device - without any tensile load on the support rod 2 - is already held securely and in such a manner that it cannot be lost in the rock crevice. In this clamping position, the climbing device can now be subjected to a tensile load by way of the support rod 2. A bore 11 is provided in the support rod between the pivot pin 4 and the stop pin 12 for the attachment of a climbing rope or the like. Alternatively, or in addition to the bore 11, it may be advantageous to provide a bore 11 a for the attachment of a carrying rope at the lower end 18 of the support rod. When the climbing device is used horizontally, the provision of a bore 11 above the stop pin 12 ensures a short lever arm, due to which damage to the support rod is largely precluded.

In the case of a tensile load on the support rod 2, the force acting in the pivot pin axis leads to rolling of the curve sections 21 and 22 on the rock walls 19, in which case the profiled curve section 21 prevents the device from sliding out of the crevice. On the other hand, the smooth curve section 22 ensures gentle sliding or tightening into the final clamping position. In this way, each clamping plate 1 is held securely between two rock walls 19, without any load being applied to the pivot pin 4 on account of the clamping forces occurring.

For releasing the clamping device - irrespective of the intensity of the effective clamping forces solely a displacement of the actuating member 5 in the direction of the lower end 18 of the support rod 2 is required, due to which the clamping plates are swung out of their clamping position into their inoperative position against the force of the helical spring 7, so that the clamping device can be removed from the crevice.

In the embodiment illustrated in Figure 5, the same parts as in the embodiment according to Figures 1 to 3 are given the same reference numerals.

The support rod 2 has a lower end section 2a of smaller dimensions, so that a shoulder is produced with respect to the support rod 2, which shoulder serves as a stop for the actuating member 5 guided on the lower section 2a. The actuating member 5 preferably comprises a central bore, through which the section 2a of the support rod 2 passes. A ball end 14 is attached, for example screwed to the free end of the section 2a, in which case a compression spring 13 is located between the ball end 14 and the actuating member 5. On account of the compression spring 13, the actuating member 5 is forced in the direction of its upper inoperative position in abutment with the support rod 2.The actuating member is connected by way of rigid connecting members 10 to the clamping plates 1, so that the compression spring 13 by way of connecting members 10 also forces the clamping plates 1 in the same direction into their clamping positions. Therefore, the leg springs provided in the embodiment according to Figures 1 to 3 between the clamping plates 1 and the support rod 2 may be dispensed with, so that the spacing of the clamping plates 1 from the support rod 2 is reduced further. The clamping plates are attached to the end of the support rod 2 by means of a bearing bolt 4' and a nut 4" screwed to the bearing bolt 4', in which case solely washers 6 are provided on both sides of a clamping plate. The bending forces acting on the bearing bolt 4' are reduced to a minimum, so that the bolt is laregly loaded solely in shear.Therefore, the bearing bolt may even have smaller dimensions than in the prior art, which provides considerable advantages with regard to a reduction in weight of the climbing device according to the invention. In addition, the short pivot pin or bearing bolt 4' reduces the overall axial length (width of the climbing device), so that the latter can now be clamped securely even in narrow, relatively flat crevices.

The climbing device illustrated in Figures 6 and 7 comprises a support rod 2 composed of two preferably rectangular, parallel flat sections 2b. A screw bolt 31 passes approximately through the centre of the flat sections 2b, which screw bolt supports a spacer sleeve 30 located between the flat sections 2b. The screw bolt 31 is secured by a nut 35, due to which the flat sections are fixed according to the height of the spacer sleeve lying at a distance apart and congruent with respect to each other.

At one end of the support rod 2 or flat sections 2b, a screw bolt 33 is inserted, which supports a spacer sleeve 32 and is secured by a nut 34. The spacer sleeve 32 preferably lies between the flat sections 2b and forms a pivot pin for the single clamping plate 1, which is mounted eccentrically approximately in the centre of the spacer sleeve 32 by means of spacers or washers 6 arranged respectively between the flat sections 2b and the clamping plate 1 and is held between the flat sections.

The actuating member 5 is arranged at right angles to the planes determined by the flat sections 2b and consists of a round bar, which is longer than the spacing between the flat sections 2b and thus projects on both sides beyond the support rod 2. The actuating member 5 preferably bears against the longitudinal edges 36 of the flat sections 2b, which lie on the side of the support rod 2 remote from the curve section 21 of the clamping plate 1. The curve section 21 is the curve section of the clamping plate, which - in the inoperative position of the clamping plate 1 according to Figure 5 is at the greatest distance from the pivot pin 32, in which case this distance is measured perpendicular to the longitudinal central axis of the support rod 2.

The connecting members 10 attached to the actuating member 5 extend below the screw bolt 31 or the spacer sleeve 32, lying between the spacer sleeve 32 and the spacer sleeve 30 between the flat sections 2b, approximately in a straight line obliquely upwards, in which case the free end 17 of the connecting member 10 is bent and engages in the clamping plate 1 somewhat above the pivot pin (spacer sleeve 32). In the embodiment illustrated according to Figures 6 and 7, a connecting member 10 is respectively provided on both sides of the individual clamping plate 1, so that an easy adjusting movement of the clamping plate 1 free from tilting is ensured.

In the embodiment according to Figure 8, two flat sections 2b are again provided in the manner described previously in that they are congruent and connected to each other at a distance apart and they form the support rod 2. Passing through one end of the support rod 2 is a spacer sleeve 32, whereof the free ends respectively form the pivot pin for a clamping plate 1. The clamping plates 1 are retained on the spacer sleeve by means of screw bolt 33 inserted through the spacer sleeve 32 and a lock nut 34. On both sides of each clamp ing plate 1, a washer 6 is respectively provided, so that a washer 6 is respectively provided, so that a washer 6 lies between the clamping plate and the outer side of a flat section 2b and between the clamping plate 1 and the head of the screw bolt 33 or its lock nut 34.

The actuating member 5 again bears loosely against the longitudinal edge 36 of the flat sections 2b, which is remote from the curve section 21 lying at the greatest distance from the pivot pin (spacer sleeve 32) of the clamping plate 1 (the distance is measured perpendicular to the longitudinal central axis of the support rod 2). The connecting members 10 extend outside the support rod 2 at a slight distance parallel to the flat sections 2b and engage respectively with an outwardly bent end 17 from inside on a clamping plate 1 respectively somewhat above the mounting. Seen in side view, the connecting members 10 again extend below the spacer sleeve 32 between the longitudinal central axes of the screw bolts 31 and 33, inclined approximately in a straight line obliquely forwards.

The guidance of the connecting members 10 illustrated in the embodiments 6 to 8 has the advantage that in particular the spacer sleeve 32 serving as a pivot pin can be used simultaneously as a stop for limiting the upper inoperative position of the clamping plate. The coil or leg springs 7 exert a restoring force on a clamping plate acting in the direction of arrow 40, (Figure 5) and move the latter in the direction of the arrow until the rigid connecting members 10 come to bear on the spacer sleeve 32, due to which - since the actuating member 5 bears against the longitudinal edge 36 and the connecting members 10 are rigid - the restoring movement is stopped. The clamping plates are able to swing by means of the actuating member 5 to such an extent until their edges extending parallel to each other, which connect the curve sections 21 and 22 to each other, lie approximately parallel to the longitudinal edges 36 and 37 of the support rod 2 or of the flat sections 2b. The clamping plates therefore have a swinging range of approximately 90 , which is achieved on account of the loose abutment or guidance of the actuating member 5 on the longitudinal edge 36 of the support rod 2.

Claims

1. A climbing device for mountaineers, for releasable clamping in a rock fissure, crevice or the like, consisting of a support rod and a pivot pin located at one end thereof with at least one clamping plate arranged eccentrically thereon, said plate being pivotable about a pivot pin axis and is acted upon in use by force torwards a clamping position and is movable in the opposite direction by way of an actuating member guided on the support rod, wherein each clamping plate comprises contact surfaces lying opposite each other on an end face thereof for the abutment of said clamping plate when in its clamping position on both sides of the crevice and that the contact surfaces are constructed as curved sections.

2. A climbing device according to claim 1, wherein said curved sections are of substantially corresponding shape.

3. A climbing device according to claim 2, wherein the curved sections are relatively disposed whereby in said clamping position in a crevice having parallel side walls, the contact points of the curved sections with said walls having the substantially same curve coordinates.

4. A climbing device according to claim 1, wherein at least one curved section is discontinuous.

5. A climbing device according to any one of claims 1 to 3 wherein the curved sections are constructed as involutes.

6. A climbing device according to any one of claims 1 to 3, wherein the curved sections are constructed as cycloids.

7. A climbing device according to any one of claims 1 to 3, wherein the durved sections are constructed as orthocycloids.

8. A climbing device according to any one of claims 1 to 7, wherein the clamping plate is symmetrical about a centre line thereof.

9. A climbing device according to any one of claims 1 to 8, wherein the points of application of the clamping forces on a clamping plate on opposed sides thereof have a differing spacing with respect to said pivot pin axis.

10. A climbing device according to any one of claims 1 to 9, wherein the curved section of one contact surface has a toothed profile.

11. A climbing device according to claim 10, wherein the curved section of another contact surface has a smooth surface.

12. A climbing device according to claim 11, wherein the tooth profiled curved section lies at a greater distance from the pivot pin axis than the curved section having a smooth construction.

13. A climbing device according to claim 12, wherein a clamping plate is mounted on the lower half of said pivot pin, in the region of lesser inclination of the smooth curved section.

14. A climbing device according to any one of claims 1 to 13, where each clamping plate is connected to the actuating member respectively by a substantially rigid connecting member.

15. A climbing device according to claim 14, wherein each connecting member acts on the clamping plate in the upper half thereof substantially diagonally opposite said pivot axis with said support bar disposed therebetween.

16. A climbing device according to any one of claims 1 to 15 wherein the actuating member embraces the support rod and is guided to slide thereon.

17. A climbing device according to any one of claims 1 to 16, wherein in use the clamping plate is forced into its clamping position by a force exerted on the actuating member.

18. A climbing device according to claim 17, wherein a compression spring is located between the lower end of the support rod and the actuating member.

19. A climbing device according to any one of claims 1 to 16, wherein the pivot pin pass s through the support rod and a clamping plate is respectively located on each of its free ends.

20. A climbing device according to claim 19, wherein between each clamping plate and the support rod a leg spring acts for forcing the clamping plate into its clamping position.

21. A climbing device according to any one of claims 1 to 20, with an opening provided in the support rod for the passage and attachment of a cable, wherein the opening is located between the pivot pin and the actuating member is directly above an upper inoperative position of the actuating member.

22. A climbing device according to any one of claims 1 to 21, wherein the support rod consists of two like spaced flat sections.

23. A climbing device according to claim 22, wherein the clamping plate is mounted at one end of the support rod between the flat sections.

24. A climbing device according to claim 23, wherein acting on each side of the clamping plate is a connecting member which connects the clamping plate to the actuating member.

25. A climbing device according to claim 24, wherein the connecting members extend between the flat sections.

26. A climbing device according to claim 14 when dependent on claim 12, wherein the actuating member is guided to bear loosely along a longitudinal edge of the support rod, which lies remote from the curved section which is located at a greater distance from the pivot pin.

27. A climbing device according to claim 26, wherein the connecting members extend substantially in a straight line inclined obliquely forwards below the pivot pin and act on the clamping plate on a longitudinal edge of the support rod remote from the actuating member.

28. A climbing device substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 4, Figure 5, or Figures 6 to 8 of the accompanying drawings.