GB2206373A

GB2206373A - Rope descent regulator

Info

Publication number: GB2206373A
Application number: GB08715276A
Authority: GB
Inventors: Andrew William Taylor; David Allport
Original assignee: ALPHIN RESCUE EQUIPMENT LIMITE
Current assignee: ALPHIN RESCUE EQUIPMENT LIMITE
Priority date: 1987-06-30
Filing date: 1987-06-30
Publication date: 1989-01-05
Anticipated expiration: 2007-06-30
Also published as: GB2206373B; GB8715276D0

Abstract

A rope descent regulator comprises a sheaf block comprising side plates 10, 11 pivotally connected at one end by a spring loaded pivot 12. Non-rotatable sheaf elements 13, 15 are mounted on plate 10, and 14 on plate 11. An arcuate slot is provided for a guide head on each sheaf element in the opposied plate. The plates are relatively rotatable to move sheaf element 14 in an arcuate path A relative to and between the sheaf elements 13, 15. A threaded rod or screw 19 running in a block 20 on plate 11 bears on sheaf element 13 so that the penetration of sheaf element 14 between elements 13, 15 can be preset, and thus the friction on a rope 23 which is reeved over the sheaf elements. <IMAGE>

Description

Rope Descent Regulator This invention-relates to a rope descent regulator, for controlling the speed of descent of a person or load down a rope.

A rope descent regulator, or 'descender' may be used for example in descent by absailing, and in its simplest form may comprise a sheaf block through which the rope is threaded, and the block secured to the user by harness or the like. The tension of the rope, and thus the friction in the block is controlled by manipulation by the user of the rope 'tail' below the block. This requires skill and experience, and does not leave the user free to perform other operations while descending such as controlling a stretcher, geological exploration, etc.

There has been proposed (Lewis, British Patent Application No.

2,024,912) a descender comprising fixed sheaf elements between side plates, and a third sheaf element which is mounted on an arm of a lever pivoted to the plates, and the other arm of which is formed as a handle.

The third sheaf element is displaceable relative to the other two, thereby controlling the friction on the rope in the descender, and thus the rate of descent. In practice, this descender must be continuously manipulated by the user, and progress tends to be jerky, as the regulation tends to be of the onn/off type. The user can halt to inspect locations of interest, for example, but the descender is not presetable, and must be continuously controlled.

An object of the present invention is to provide a descent regulator which enables the friction between the rope and regulator to be preset so that a load can be lowered at a steadY rate, without continuous control of the regulator being required. The load could be a user who wishes to concentrate on other matters, such as controlling the descent of a stretcher, or studying rock formations, etc. or an inexperienced absailer, a slightly injured casualty, or a passive load such as a stretcher and casualty which may be lowered from a structure with free space below the point of descent.

From a first aspect the invention provides a rope descent regulator comprising a body having two fixed sheaf elements, a third sheaf element which is displaceable relative to the fixed sheaf elements, and continuously adjustable means for presetably varying the position of the third sheaf element relative to the fixed sheaf elements.

The fixed sheaf elements are preferably mounted on a first side plate, and the third, moveable, sheaf element is preferrably mounted on a second side plate, the side plates being pivoted together so that they lie in and are relatively displaceable in parallel planes. The pivot is preferrably spring loaded to bias the side plates to overlie each other.

Preferrably the means for relatively displacing the fixed and moveable sheaf elements comprises a treaded rod or screw, bearing on one of the fixed sheaf elements, the rod being rotatable axially in a counter threaded block on the second side plate, whereby rotation of the rod in one sense will tend to open the plates apart against the bias of the spring, thus reducing the penetration of the third sheaf element bewteen the fixed sheaf , and rotation of the rod in the other sense will tend to close the plates with the bias of the spring, thus increasing penetration of the third sheaf eleme between the fixed sheaf elements.

From another aspect, the invention provides a rope descent regulator comprising a first side plate, and a second side plate, said side plates being disposed in parallel spaced apart planes, and pivotally connected in one end region of said plates, said plates being biased intoan overlying position wherein each plate overlies the other, by means of a torsion spring acting on said pivot, said first plate mounting two spaced apart sheaf elements between said plates, said second plate mounting a third sheaf element in a position wherein said third sheaf element can move relative to said two sheaf elements on an arc centred on said pivot and passing between said two sheaf elements, continuously adjustable means bearing on an outer one of said two sheaf elements, and means on said second side plate complementary to said continuously adjustable means to enable the relative positions of said two sheaf elements and said third sheaf element to be adjustable and maintained after adjustment, thereby selecting and maintaining a desired degree of friction on a rope when reeved over and between said sheaf elements.

A preferred embodiment of rope descent regulator according to the invention will now be described, with referrence to the accompanying drawings, wherein: Fig. 1 is an elevation view of one face of a rope descent regulator according to the invention; Fig. 2 is a corresponding elevation view of the regulator from the opposite side to Fig. 1; Fig. 3 is an end elevation from the direction of arrow III in Fig. 1; and Fig. 4 is a side view similar to Fig. 1 with one side plate removed.

As illustrated in the drawings, a preferred embodiment of rope desc ent regulator according to the invention is in the general form of a sheaf block, comprising a first side plate 10, and a second side plate 11, which are pivotally connected at one end by a pivot pin 12.

non-rotatable sheaf elements 13, 14, and 15 are mounted in the sheaf block, sheaf elements 13 and 15 being mounted on the first side plate 10, and having mushroom headed studs 13a, 15a sliding in arcuate slots 16, 18 in the second side plate 11. Sheaf element 14 is mounted on the second side plate 11, and has a mushroom headed stud 14a slidable in an arcuate slot 17 in the first side plate 10. The slots 16, 17, and 18 lie on arcs centred on the axis of pivot pin 12.

A threaded rod 19, adapted to run in a counter-threaded bore in a block 20 has an end 19a Whiail bears on a surface of sheaf element 13.

Sheaf element 13 is the radially outermost of the sheaf elements from pivot block 12. Block 20 is fixed to the inner surface of the second side plate 11, and the rod 19 is provided with a winged head 21, so that the rod can be rotated manually. Rotation of the rod 19 so that it displaces in the direction of sheaf element 13 forces the side plates 10, 11 apart, against the force of a torsion spring 22 on the pivot pin 12, the spring acting to bias the side plates to overlie one another, thus causing sheaf element 14 to be displaced relative to sheaf elements 13, 15 along the arc of arrow A (Fig. 4).

In use, the plates are pivoted apart and held while a loop of rope 23 is placed about sheaf element 14, and between sheaf elements 13, 15. The spring 22 is allowed to return the side plates to their closed position. Friction on the rope 23 is varied by displacing the sheaf element 14 realative to the sheaf elements 13, 15 by using the screw threaded rod 19. The rod 19 is screwed in to move sheaf element 14 to the right in Fig. 4, thus increasing the length of the loop in the regulator and decreasing friction on the rope; and conversely screwed out to displace the sheaf element 14 to the left in Fig. 4 towards the other sheaf elements, shortening the loop, and increasing friction.

In distinction from known rope descent regulators, using the rope descent regulator according to the invention, making use of the screw rod 19, the degree of friction, and thus the rate of descent carX be preset, and this will be maintained until the setting of the screw is altered. The regulator can thus be used by novice absailers, or in cliff rescue Where the user's main concern is to manipulate casualties or stretchers, which would be impossible if the user had to concentrate on manipulating the control of his own descent regulator. Further, the regulator of the invention may be used preset to enable inert loads to be dispatched, such as a laden stretcher, in sitaations where there is no adjacent rock or building face to cause a hazard due to pendulum swinging of the load, without direct supervision and control by one or more persons descending alongside.

Claims

1. A rope descent regulator comprising a body having two fixed sheaf elements, a third sheaf element which is displaceable relative to the first pair of sheaf elements and continuously adjustable means for presettably varying the position of the third sheaf element relative t the first pair of sheaf elements.

2. A rope descent regulator according to Claim 1, wherein the first pair of sheaf elements are mounted on a first side plate, and the third sheaf element is mounted on a second side plate, the side plates being pivoted together so that they lie in and are relatively rotatable in parallel planes.

3. A rope descent regulator according to Claim 2, wherein the pivot is spring loaded to bias the side plates to overlie each other.

4. A rope descent regulator according to any preceding Claim, wherein the means for relatively displaceing the first pair, and third sheaf elements comprises a threaded rod or screw, bearing on one of the first pair of sheaf elements, said rod or screw being rotatable in a counterthreaded block on said second side plate, whereby rotation of the rod in one sense will tend to open the plates apart against the bias of a spring, thus reducing penetration of the third sheaf element between the first pair of sheaf elements, and rotation of the rod in the other sense will tend to allow the plates to close under the bias of the spring, thus allowing increased penetration of the third sheaf element between the first pair of sheaf elements.

5. A rope descent regulator according to Claim 1, comprising a first side plate, a second side plate, said side plates being disposed in parallel spaced apart planes and pivotally connected in one end region of each plate, said plates being biased into a mutually overlyin position wherein each plate overlies the other, by means of a torsion spring acting on said pivot; said first plate mounting said first pair of sheaf elements between said plates, sais second plate mounting said third sheaf element in a position wherein said third sheaf element can move relatively to said first pair of sheaf elements on an arc centred on said pivot and passing between sais pair of sheaf elements, the continuously adjustable means bearing on an outer one of said pair of sheaf elements, and means on said second side plate complementary to said continuously adjustable means to enable the relative positions of said pair of sheaf elements and said third sheaf element two be adjustable and maintained after adjustment, thereby selecting and maintaining a desired degree of friction on a rope reeved over and between said sheaf elements

6. A rope descent regulator according to Claim 5, wherein the rope is passed between the said pair of sheaf elements and the third sheaf element, creating a loop or bight between the side plates, the regulator being openable against the spring bias to place the rope over the pair of sheaf elements, and closable with or by the spring bias to allow the third sheaf element to push the rope inwards between the pair of sheaf elements and itself to form a loop or bight and create friction between the rope and the sheaf elements, such friction being adjustable by presetting the penetration of the third sheaf element between the pair of sheaf elements using the continuously adjustable means.

7. A rope descent regulator, substantially as hereinbefore described, with referrence to and as illustrated in the accompanying drawings.