GB2503737A

GB2503737A - Carabiner

Info

Publication number: GB2503737A
Application number: GB1212080.4A
Authority: GB
Inventors: Simon N Coombes; Elliot James Tanner
Original assignee: DMM International Ltd
Current assignee: DMM International Ltd
Priority date: 2012-07-06
Filing date: 2012-07-06
Publication date: 2014-01-08
Anticipated expiration: 2032-07-06
Also published as: GB2503737B; GB201212080D0

Abstract

A carabiner comprises a body 10 having a free end and a pivot end between which is defined an opening. A gate 24 is carried on the body 10 close to the pivot end, the gate 24 being pivotable between a closed position, in which it closes the opening, and an open position. A locking mechanism is carried on the gate which, in a locked condition, prevents movement of the gate from the closed position. In an unlocked condition, the locking mechanism allows movement of the gate 24 to its open position. The locking mechanism includes a sleeve 40 that can be manipulated by a user to place the locking mechanism in the unlocked condition. In order to place the locking mechanism in the unlocked condition, the sleeve 40 must be subject sequentially to an initial rotation about the gate 24, translation along the gate 24, and further rotation about the gate 24.

Description

Carabiner This invention relates to carabiners.

Carabiners are ubiquitous components used in rope access) climbing, caving and many other applications where one component is to be releasably connected to another component. A typical carabiner comprises an incomplete loop of metal, typically C-shaped, and with first and second ends. A gate is pivotally connected to the ioop close to its first end. The gate can move between a closed position, in which it extends to the second end to complete the loop, and an open position in which there is a gap between the gate and the second end to allow a rope or other component to pass into or out of the loop. In its most basic form, the gate is simply biased by a spring to the closed position. However, in most practical cases some form of locking arrangement is provided to retain the gate in the closed position until a user performs some specific unlocking action.

Numerous locking arrangements have been proposed. In general, there is always a compromise between the security of the locking arrangement and its convenience in use. Different applications call for different levels of security. One particularly onerous application arises from use of carabiners by arborists performing rope climbing operations during maintenance of trees. In such operations, it is highly likely that the gate and associated locking components will make contact with tree branches and moving ropes, which are capable of applying large forces in random directions to the gate and its locking components. This can result in the gate becoming unlocked and opening, an event commonly called "roll out".

An aim of this invention is to provide a carabiner with a locking arrangement that achieves a very high level of security whilst maximising the convenience of use of the carabiner.

To this end, the present invention provides a carabiner comprising a body having a free end and a pivot end between which is defined an opening, a gate carried on the body close to the pivot end, the gate being pivotable between a closed position, in which it closes the opening, and an open position, and a locking mechanism carried on the gate which, in a locked condition, prevents movement of the gate from the closed position and in an unlocked condition, allows movement of the gate to its open position, the locking mechanism including a sleeve that can be manipulated by a user to place the locking mechanism in the unlocked condition, wherein in order to place the locking mechanism in the unlocked condition, the sleeve must be subject sequentially to an initial rotation about the gate, translation along the gate, and further rotation about the gate.

It is most unlikely that such three unlocking steps required before the carabiner can be opened will occur, other than by intention.

The security of the carabiner can be further enhanced by the requirement that the further rotation is in a direction opposite that of the initial rotation.

Typically the locking mechanism includes biasing means arranged such that each rotation of the sleeve and the translation of the sleeve required to place the locking mechanism in the unlocked condition must be made against the action of the biasing means. In addition, the carabiner typically includes biasing means that urges the gate towards the closed position. It is further preferred that the biasing means cause the gate to move towards the closed position and to place the locking mechanism in the locked condition without intervention from a user. To achieve this latter aim, the locking mechanism is most typically configured such that it cannot be moved from its unlocked condition unless the gate is in the closed position.

The locking mechanism may include inner and outer tubular sleeves, the inner sleeve being carried on the gate and the outer s'eeve being carried on the inner sleeve. In such embodiments, in the locked condition, the inner sleeve retains a free end of the gate adjacent to the free end of the body. Typically, the sleeve can be rotated about the gate to place the locking mechanism in the unlocked condition following rotational, translational and counter-rotational movement of the outer sleeve. The amount of each rotation is typically determined by the amount of rotation required to move the sleeve between a fully locked and a fully unlocked condition. A greater required amount of each rotation may increase the security of locking of the carabiner at the expense of its ease of use. For greatest security it is to be preferred that each rotation is at least approximately 9Q0. However embodiments may be configured to require lesser rotation, provided that this does not compromise the effectiveness of locking.

The carabiner may include guide means that prevents translational movement between the inner and the outer sleeve prior to relative rotational movement between the inner and the outer sleeves from the locked condition. In such embodiments, the guide means typically constrains the inner and the outer sleeves to rotate together on the gate following rotational and translational movement of the outer sleeve relative to the inner sleeve from the locked condition.

An embodiment of the invention will now be descr bed in detail, by way of example, and with reference to the accompanying drawings, in which: Figures 1 and 2 are front and perspective views of a carabiner being a first embodiment of the invention with operative components being shown as a cut-away section; Figures 3, 4 and 5 show an inner sleeve that is a component of the embodiment of Figures 1 and 2; Figures 6 and 7 show an outer sleeve that is a component of the embodiment of Figures 1 and 2; Figure 8 shows a bush that is a component of the embodiment of Figures 1 and 2; Figure 9 is an exploded view of the embodiment of Figures land 2; and Figures 10 to 15 show the carabiner of Figures 1 and 2 in sequence between a locked condition and an open condition.

With reference to the drawings, a carabiner includes a body 10 formed as an incomplete, generally planai; loop. The body 10 has ends referred to as the free end 12 and the pivot end 14, that are spaced apart from one another, an opening 16 being defined between the ends. Portions of the body 10 close to the ends 12, 14 face generally towards one another across the opening 16. Close to the pivot end 14, the body has a flattened portion 20. The shape of the body 10 in this embodiment might be described as "C-shaped". Howeven this is but one of many possibilities. As is well-known, carabiners are made in many different shapes, sizes and configurations, and may include additional eyes, rope guides and other features: the present invention is applicable to a large range of them. The free end of the body 10 is formed with a bulbous projection 34.

A gate 24 is carried on the body. The outer surface of the gate 24 is generally cylindrical.

The gate 24 has a slot 26 that extends across it at one end, which will be referred to as the pivot end. The flattened portion 20 of the body 10 extends into the slot 26, and is secured there by a pin 28 that extends through the gate 24 and the flattened portion 20, and has a projection that extends substantially beyond one side of the gate 24. The gate 24 can pivot about the pin 28 in the plane of the body 10. The end of the gate opposite to the pivot end will be referred to as the closing end. A receiving slot 32 is formed in the gate 24 close to the closing end. The receiving slot 32 extends, parallel to the slot 26 in the pivot end, part way across the gate 24. The receiving slot 32 has a widened portion remote from the free end of the gate 24.

The gate 24 can pivot between a closed position [Figures 10 to 14] and an open position [Figure 15]. In the open position, the gate 24 is displaced into the body 10. In the closed position, the free end 12 of the body 10 enters into the receiving slot 32. The bulbous portion 34 of the free end portion 12 enters the widened portion of the receiving slot 32 thereby preventing the free end 12 of the body 10 being pulled from the gate 24 when the carabiner is placed under tensile load. A return spring 22 urges the gate 24 towards the closed position in a conventional manner.

A generally cylindrical inner sleeve 40 is carried on the gate 24, the inner sleeve 40 being shaped and dimensioned to be a close fit on the gate 24, such that it can rotate on the gate. The outer surface of the inner sleeve 40 has a step 39, such that the outer diameter of the inner sleeve 40 is lesser for approximately two-thirds of its length from the pivot end compared with its diameter at the free end. A notch 49 is formed axially into the step 39. At its end closest to the pivot end of the gate 24, there are recessed regions that extend axially into the inner sleeve (effectively shortening the axial length of the inner sleeve 40). A first of such regions 42 extends by approximately 900 and a second region is a slot 46 formed diametrically opposite one end of the first region. A comparatively narrower geode slot 47 extends from the slot 46 towards the free end of the gate 24. At its end closest to the free end of the gate 24, an axially-extending slot 44 is formed that is aligned with the slot 46 of the opposite end.

The projecting part of the pivot pin 28 projects into the first recessed region 42 of the inner sleeve 40 to limit the extent by which it can rotate about the gate to approximately 900. An inner biasing spring 48 acts between the gate 24 and the inner sleeve to urge the inner sleeve 40 to rotate to a position in which the projecting part of the pivot pin 28 is at one end of the first recessed region 42 and the slot 46 is adjacent to the opposite end of the pivot pin 28.

A generally cylindrical outer sleeve 50 is carried on the inner sleeve 40, the outer sleeve being shaped and dimensioned to be a close fit on the inner sleeve 40 and can slide and rotate on the inner sleeve 40. An annular space between the inner sleeve 40 and the outer sleeve 50 is occupied by a bush 62. A region 52 of an outer surface of the outer sleeve 50 is knurled or otherwise treated to assist a user in gripping it. As with the inner sleeve 40, the outer sleeve 50 has recessed regions at each of its ends. At its end closest to the pivot end of the gate 24, first of such regions 54 extends by approximately 900, and a second region 56 is a slot formed diametrically opposite one end of the first region. At its end closest to the free end of the gate 24, an axially-extending slot 58 is formed that is aligned with the slot 56 of the opposite end.

Internally, a circumferential groove 51 is formed in the inner surface of the outer sleeve 50. Two diametrically opposed apertures 53 extend radially through the outer sleeve 50 from the base of the groove.

The projecting part of the pivot pin 28 projects into the first recessed region 54 of the outer sleeve 50 to limit the extent by which it can rotate about the gate to approximately 90°. An outer biasing spring 60 acts between the inner sleeve 40 and the outer sleeve to urge the outer sleeve 50 to rotate to a position in which the projecting part of the pivot pin 28 is at one end of the first recessed region 54 and the slot 56 is adjacent to the flattened portion 20 at the pivot end 14 of the body 10. The direction in which the outer biasing spring 60 acts is opposite to that of the inner biasing spring 48.

The bush 62 is carried in the outer sleeve 50, surrounding the inner sleeve 40. The bush 62 is formed as a short cylinder with an internal diameter that allows it to rotate and slide on the part of the inner sleeve 40 of lesser diameter, but not the part of greater diameter. The bush has a tangential slit 64 extending through its axial length to allow its diameter to be reduced to enable assembly. A spigot 66 projects axially from one end surface of the bush 62. Two pegs 68 [just one being shown in Figure 8] project radially from the bush 62. The pegs 68 are diametrically opposite one another and displaced 90° from the spigot 66. In the assembled carabiner, each peg is retained in a respective one of the radial apertures 53 in the outer sleeve 50, which retains the bush against translational or rotational movement within the outer sleeve 50. Once assembled, the outer sleeve 50 and the bush 62 effectively operate as a single component.

The configuration of the carabiner when closed and locked is shown in Figures 1, 2, 10 and 11. It will be seen that the inner sleeve 40 retains the free end 12 of the body 10 within the receiving slot 32 of the gate 24, thereby preventing the gate 24 from moving from its closed position. In this position, the spigot 66 of the bush 62 is in contact with the step 39 of the inner sleeve, which prevents longitudinal movement of the outer sleeve 50 on the inner sleeve 40. The spigot 66 of the bush are free to move around the step 39 of the inner sleeve 40, which permits rotation of the outer sleeve 50 on the inner sleeve 40. The extent of this rotational movement is limited by end surfaces of the recess 54 making contact with the pivot pin 28.

The first action that must be performed in a sequence to open the carabiner is for the outer sleeve 50 to be rotated around the inner sleeve 40 against the outer biasing spring to the limit imposed by the projecting part of the pivot pin 28 reaching the limit of the first recessed region 54 of the outer sleeve 50, to the position shown in Figure 12. In this position, the guide spigot 66 of the bush 62 is in alignment with the notch 49 of the step 39 of the inner sleeve 40.

The outer sleeve 50 is then displaced longitudinally along the inner sleeve 40, away from the pivot pin 28, to the position shown in Figure 13, this movement being permitted by the spigot 66 entering into the notch 49. The spigot 66 and the notch 49 are preferably tapered or otherwise shaped to assist and guide the spigot 66 into the notch 49.

In the final unlocking step, the outer sleeve 50 is counter-rotated back to its initial angular position, without first changing its longitudinal position. Since the spigot 66 is within the notch 49, the inner sleeve 40 is caused to rotate with the outer sleeve 50, against the inner biasing spring 48 to the position shown in Figure 14. The notch 49 and the spigot 66 are preferably shaped to ensure that a positive drive occurs between them. In this position, the axially-extending slots 44, 58 of the inner and outer sleeves 40, 50 are now aligned with the receiving slot 32 of the gate 24 and the slot 46 of the inner sleeve 40 at the pivot end of the gate 24 is aligned with the flattened portion 20 of the gate 24. The free end portion 12 of the body can therefore pass out of the receiving slot 32, thereby allowing the gate 24 to move to its open position, as shown in Figure 15, with the slots 26, 46 and 56 adjacent to the pivot end of the gate 24 receiving the flattened portion 20 of the body 10.

The amount by which the sleeves rotate and then counter-rotate might be less than or more than 900 as is the case in this embodiment. The amount of rotation generally must not be less than is required to ensure that the axially-extending slots 44, 58 of the inner and outer sleeves 40,50 move between a position in which the receiving slot 32 of the gate 24 is completely obstructed to a position in which they are aligned with the receiving slot 32 of the gate 24.

While the gate 24 is open, rotation of the inner sleeve 40 and outer sleeve 50 is prevented by the limits of its recessed regions 54, 56; 42, 46 making contact with the flattened portion 20 of the body. This prevents the locking mechanism from returning to the locked condition until the gate 24 is closed.

When the open gate 24 is released, the outer biasing spring 60, the inner biasing spring 48 and the return spring 22 cause the carabiner to close and lock automatically and without manual intervention. The spigot 66 and the notch 49 are shaped such that a component of the force of the inner biasing spring 48 urges the bush 62 longitudinally along the inner sleeve 40, thereby obviating the need for a longitudinal return spring [although such a spring maybe provided if required).

The principal components of the carabiner are most typically formed from a strong, lightweight alloy by forging or other forming techniques. In principle, other materials, such as composites, could be used in the construction of some components where the loading imposed on them allows.

Claims

Claims 1. A carabiner comprising a body having a free end and a pivot end between which is defined an opening, a gate carried on the body close to the pivot end, the gate being pivotable between a closed position, in which it closes the opening, and an open position, and a locking mechanism carried on the gate which, in a locked condition, prevents movement of the gate from the closed position and in an unlocked condition, allows movement of the gate to its open position, the locking mechanism including a sleeve that can be manipulated by a user to place the locking mechanism in the unlocked condition, wherein in order to place the locking mechanism in the unlocked condition, the sleeve must be subject sequentially to an initial rotation about the gate, translation along the gate, and further rotation about the gate.
2. A carabiner according to claim 1 in which the further rotation is in a direction opposite that of the initial rotation.
3. A carabiner according to claim 1 or claim 2 that includes biasing means arranged such that each rotation of the sleeve and the transbtion of the sleeve required to place the ocking mechanism in the unlocked condition must be made against the action of the biasing means.
4. A carabiner according to any preceding claim that includes biasing means arranged to urge the gate towards the closed position.
5. A carabiner according to claim 3 or claim 4 in which the biasing means cause the gate to move towards the closed position and to place the locking mechanism in the locked condition without intervention from a user.
6. A carabiner according to any preceding claim in which the locking mechanism is configured such that it cannot be moved from its unlocked condition unless the gate is in the closed position.
7. A carabiner according to any preceding claim in which the locking mechanism includes inner and outer tubular sleeves the inner sleeve being carried on the gate and the outer sleeve being carried on the inner sleeve.
8. A carabiner according to claim 7 in which, in the locked condition, the inner sleeve retains a free end of the gate adjacent to the free end of the body.
9. A carabiner according to claim 8 in which the inner sleeve can be rotated about the gate to place the locking mechanism in the unlocked condition following rotational and translational movement of the outer sleeve.
10. A carabiner according to any preceding claim in which the amount of each rotation is determined by the amount of rotation required to move the sleeve must be rotated between a fully locked and a fully unlocked condition.
11. A carabiner according to any preceding claim in which each rotation is at least approximately 90°.
12. A carabiner according to any one of claims 7 to claim 11 including guide means that prevents translational movement between the inner and the outer sleeve prior to relative rotational movement between the inner and the outer sleeves from the locked condition.
13. A carabiner according to claim 12 in which the guide means constrains the inner and the outer sleeves to rotate together on the gate following rotational and translational movement of the outer sleeve relative to the inner sleeve from the locked condition.
14. A carabiner according to claim 13 in which the inner and the outer sleeves have slots that are mutually aligned during such constrained rotation, a free end of the gate being able to pass through the mutually aligned slots when the locking mechanism is in the unlocked condition.
15. A carabiner substantially as described herein with reference to the drawings.