The present invention relates to a self-blocking descender-belay device which is designed to be used to control the paying-out of a rope, for example for the descent of a person down a rope, or for belaying of a person.
Various descender-belay device structures are already known, for example such as that which is described in document EP 0 688 581 B1.
A known descender-belay device of this type comprises:
In this known descender-belay device, the cam return spring thrusts the cam away from the braking nose, in order to assist the sliding of the rope in the absence of tension on the rope.
When the cam manoeuvring unit is released during a movement of descent down the rope, the tension on the rope thrusts the cam towards the braking nose, such that the rope is pressed by the cam against the braking nose. This results in braking of the movement of descent.
However, it is found in this device that the automatic triggering of the braking requires tension of the rope which is sufficiently sudden and strong to drive the cam against its return spring. In the presence of reduced tension, or relatively slow application of the tension of the rope, the blocking of the rope does not take place, and the self-blocking function is not fulfilled.
On the other hand, the deliberate reduction of braking by the user is not regular. Firstly, by using the cam manoeuvring unit in order to allow the rope to pay out with braking, the paying-out of the rope is relatively jerky. Secondly, in order to supply a climber with free rope, it is necessary to inhibit the braking. This leads the user to act directly with his hand on the cam, in order to space it from the braking nose, with the risk of forgetting to release the hand when blocking is necessary.
A device according to the preamble of claim 1 is also known from document JP 2011-200 640 A. In this document, the objective is essentially to ensure automatic blocking of the rope in the absence of thrusting on the cam by the user. For this purpose, the path for passage of the rope is permanently in the form of an arc of a circle, irrespective of the orientation of the output end of the rope. The cam is arranged halfway between the two longitudinal ends of the body of the device. The paying-out of the rope is permitted only if the user thrusts the cam in rotation. Thus, this device does not make it possible to control easily the braking of the rope in order to allow it to be paid out regularly with or without a load.
The object of the present invention is to eliminate the disadvantages of the known descender-belay devices, whilst making it possible to fulfill efficiently the two contradictory functions of a descender-belay device, i.e. great ease and efficiency in permitting the deliberate paying-out of a rope, and secure blocking of the rope as soon as tension occurs, and in the absence of intervention by the user, even in the presence of a slight tension and/or a slow speed of paying-out of the rope.
It will be appreciated that these two functions are contradictory, in that easy paying-out of the rope needs great ease of spacing of the cam from the braking nose, whereas secure blocking requires great ease of displacement of the cam towards the braking nose.
In order to achieve these objectives and others, the invention proposes a self-blocking descender-belay device to control the paying-out of a rope, comprising:
As a result of the presence of the cam return spring, which thrusts the cam towards the braking nose, contrary to the arrangement indicated in the prior document EP 0 688 581 B1, in the absence of thrusting by the user the automatic blocking of the rope is ensured even in the presence of a slight tension or a slow speed of paying-out, since the spring gives rise to the start of the blocking, which then makes the descender-belay device pivot to a blocking position, in which the start of the blocking is immediately completed by the force exerted on the cam by the taut rope. The resilient thrust of the cam towards the braking nose thus reduces the blocking time very substantially, and prevents blocking faults.
Simultaneously, thanks to the wide path output which permits free orientation of the output end of the rope, contrary to the prior documents, the descender-belay device can be oriented deliberately by the user away from the blocking position, in order to provide it with a release orientation, in which the output end of the rope is in the extension of the rope input, and thus avoids thrusting the cam towards the braking nose, consequently ensuring efficient and adjustable release, even in the presence of the residual braking caused by the thrust of the cam return spring.
As a result, the range of non-triggering of the blocking of a descender-belay device of this type is reduced, and it exists only in the case when the user maintains the descender-belay device in the release orientation, whereas, as soon as the user releases the descender-belay device in the presence of tension of the rope, the rope automatically goes into the blocking orientation in which the rope envelops the cam, and ensures immediate blocking.
According to a first embodiment, in its movement towards and away from the braking nose, the cam can be guided by guide slides.
According to a preferred embodiment, the cam is mobile in rotation around a rotational cam shaft, which, in relation to the cam, is situated on the other side of the intermediate section of path, and is offset in the direction of the proximal end area.
A movement of rotation of this type is simple to carry out and to reproduce reliably, even in the presence of mud, dust, or foreign bodies which can oppose the movement of the cam. In addition, the cam is thus efficiently thrust by the rope in an appropriate manner in the two situations of blocking and release.
Preferably, the cam is supported by the second lateral guide flange for the rope.
In this case, the cam is advantageously associated with a first cam lug, which is displaced in an aperture in the form of an arc of a circle provided in the second lateral guide flange for the rope, such as to guide the cam, and to take over some of the traction forces withstood by the descender-belay device.
According to the invention, means are provided for locking the flanges in the closed position, such as to prevent any risk of untimely opening of the descender-belay device, which opening would be liable to release the rope.
According to an advantageous embodiment, this locking can be ensured by the cam itself, by associating the cam with a second cam lug which is displaced on a guide path provided in the first lateral guide flange, and by providing the guide path with two successive guide sections, i.e.:
Since the cam is thrust back by the cam return spring, the second cam lug is at the beginning of the first guide section, and opposes the rotation of the second flange, such that, by means of its second cam lug, the cam itself ensures a first locking of the second flange in the closed position.
Advantageously, a button can additionally be provided for unlocking of the second lateral guide flange relative to the first lateral guide flange.
Advantageously, the cam manoeuvring unit can comprise a lever which is articulated on one of the lateral guide flanges, and is connected mechanically to the cam, in order to displace the cam away from the braking nose by means of deliberate action by the user. Thus, when the descender-belay device is used as a descender device, the user can regulate the braking of his descent down the rope by manoeuvring the lever.
In this case, the above-mentioned unlocking button can advantageously be covered by the lever when the latter is at rest, thus preventing untimely manoeuvring of the unlocking button which can give rise to unlocking of the second flange relative to the first flange.
Preferably, the flanges have dimensions such that, in the braking position in which the cam clamps the rope against the braking nose, the cam is entirely accommodated in the transverse gap for passage of the rope. This prevents untimely manipulation of the cam away from the braking nose, and makes the user orient the descender-belay device in order to give rise to the release.
Other objectives, characteristics and advantages of the present invention will become apparent from the following description of particular embodiments, which description is provided in relation with the appended figures, in which:
In the embodiment illustrated in
In general, the self-blocking descender-belay device 1 comprises a connection device 4 and coupling means 5.
The connection device 4 is formed so as to ensure a connection with a rope 3, whilst controlling the sliding or blocking of the rope 3 in the connection device 4.
The coupling means 5 are formed so as to permit the selective coupling of the descender-belay device 1 either to a fixed point, or to the harness of a user.
The connection device 4 comprises a connection body 4a with a proximal end 4b which is connected to the coupling means 5.
The connection device 4 additionally comprises second connection means, comprising a braking nose 4e which co-operates with a cam 4d which is fitted such as to be mobile on the connection body 4a, and is designed to press the rope 3 against the braking nose 4e.
In the preferred embodiment illustrated in the figures, the coupling means 5 comprise a connector body 5a, in the form of an open ring, and a closure finger 5b.
The connector body 5a extends between a proximal end area 5c and a distal end area 5d, and has a lateral opening 5e (
For this purpose, the closure finger 5b pivots around an articulation shaft 5h which is perpendicular to the general plane of the connector body 5a in the form of an open ring.
In the embodiment illustrated, the proximal end 4b of the connection body 4a forms a continuity with the distal end area 5d of the connector body 5a, such that the connector body 5a and the connection body 4a form a unit assembly with a common rigid body formed by the connection body 4a and the connector body 5a.
As an alternative, coupling means 5 could be designed in the form of a simple aperture provided in the proximal end of the connection body 4a, i.e. without a closure finger, this aperture permitting connection by means of a snap clasp in a manner known per se.
The structure of the connection device 4 is now considered.
A first lateral guide flange 6 for the rope is integral with the connection body 4a, and integral with the braking nose 4e, the first lateral guide flange 6 for the rope preferably being oriented according to a plane perpendicular to the general plane of the connector body 5a.
A second lateral guide flange 7 for the rope, parallel to the first lateral guide flange 6 for the rope, is separated from the first lateral guide flange 6 for the rope by means of a transverse path 8 for passage of the rope (
The braking nose 4e, which is integral with the first lateral guide flange 6 for the rope, passes through the gap between the first and second lateral guide flanges 6 and 7 for the rope.
The cam 4d is engaged between the first and second lateral guide flanges 6 and 7 for the rope, and is fitted such as to be mobile towards and away from the braking nose 4e.
In practice, in the embodiment illustrated, the cam 4d is supported by the second lateral guide flange 7 for the rope, on which it is mobile in rotation around a rotational cam shaft 9. As illustrated in
In order to reduce the forces withstood by the rotational cam shaft 9, the cam 4d is associated with a first cam lug 10, which, during the rotation of the cam 4d, is displaced in an aperture in the form of an arc of a circle 7a of the second lateral guide flange 7 for the rope (
The braking nose 4e advantageously consists of a steel wear part added onto the connection body 4a, which itself is made of aluminium alloy, as can be seen in
The first lateral guide flange 6 for the rope is added and secured on the connection body 4a by rivets such as the rivets 16 and 13a (
A lever 13 is articulated on the connection body 4a and the first lateral guide flange 6 for the rope, around the rivet 13a, thus forming a rotational shaft perpendicular to the plane of the first lateral guide flange 6 for the rope, and is arranged on the outer surface of the first lateral guide flange 6 for the rope. In practice, the rivet 13a which forms the rotational shaft of the lever 13 passes through a hole 6b in the first lateral guide flange 6 for the rope, and passes through a hole 4g in the connection body 4a and through a hole 4h in the braking nose 4e, in order to co-operate with a brace 13b, which ensures simultaneously the retention of the rotational shaft 13a, the securing of the braking nose 4e on the connection body 4a, and the guiding of the second flange 7 in sliding in a slot 7b in the second lateral guide flange 7 for the rope.
The lever 13 co-operates with the end of the second cam lug 12, which extends from the guide path 11, thus allowing a user to pivot the cam 4d away from the braking nose 4e, by pivoting the lever 13 in the direction illustrated by the arrow 13c.
Thus, the lever 13 constitutes a cam manoeuvring unit which can be activated by a user in order to displace the cam 4d away from the braking nose 4e.
A lever return spring 13d returns the lever to the position of rest which is illustrated in particular in
A cam return spring 14 permanently thrusts the cam 4d in its movement between the first and second lateral guide flanges 6 and 7 for the rope, in the direction which brings the cam 4d towards the braking nose 4e.
As can be seen in these figures, the transverse path 8 for passage of the rope is delimited by the first lateral guide flange 6 for the rope, by the second lateral guide flange 7 for the rope, by the braking nose 4e, by the cam 4d, and by the connection body 4a.
The transverse path 8 for passage of the rope extends between a path input 8a in the vicinity of the braking nose 4e, and a path output 8b opposite. Between the path input 8a and the path output 8b, an intermediate section 3C of the rope 3 passes along an intermediate section of path 8c between the braking nose 4e and the cam 4d.
At the path input 8a, the input end 3A of the rope 3 can pass freely around the braking nose 4e, in order to adopt any orientation between a quasi-direct orientation as an extension of the section 3C trapped between the braking nose 4e and the cam 4d (see
According to the present invention, the path output 8b is formed such as to modify the braking of the rope 3 according to the orientation of the output end 3B of the rope 3, between a blocking orientation, illustrated in
As illustrated in
As also illustrated in
Thus, as a result of the particular arrangement of the cam 4d and its rotational shaft 9 and as a result of the particular arrangement of the path output 8b, the cam 4d is arranged such that, when the output end 3B of the rope is in the blocking orientation and passes along the blocking output portion 8d whilst enveloping the cam 4d, tension of the output end 3B of the rope then thrusts the cam 4d towards the braking nose 4e, in such a way that, when the output end 3B of the rope is in the release orientation and passes along the release output portion 8e without enveloping the cam 4d, tension of the output end 3B of the rope does not thrust the cam 4d towards the braking nose 4e, but on the contrary longitudinal sliding of the rope 3 thrusts the cam 4d away from the braking nose 4e.
During use of the self-blocking descender-belay device 1, the user orients the self-blocking descender-belay device 1 with respect to the rope, as illustrated in
In
Preferably, the user assists the sliding of the rope 3 further by pulling the output end 3B manually parallel to the traction axis I-I, in which orientation the braking is minimal.
By using the blocking position in
In order to allow the rope 3 to be put into place and removed, the second lateral guide flange 7 for the rope can be displaced between a spaced position, illustrated in
As can be seen in
In the closed position illustrated in
As can be seen in
For safety reasons, it is important to prevent selectively the free rotation of the second lateral guide flange 7 for the rope towards its spaced position, in order to avoid untimely output of the rope 3 from the self-blocking descender-belay device 1. For this purpose, a first locking means consists of providing the guide path 11 of the second cam lug 12 with a particular form, as illustrated in
In this case, the guide path 11 comprises two successive sections, i.e.:
In this case, for as long as the cam 4d is at the bottom of the guide path 11, to which it is thrust back by the cam return spring 14, the second cam lug 12 prevents any pivoting of the second lateral guide flange for the rope around the rivet 16, which itself is structured in order to constitute the flange shaft 7, since the first guide section 11a is not centered on this flange shaft 16. The opening of the self-blocking descender-belay device 1 by pivoting of the second lateral guide flange 7 for the rope is possible only by means of a double manoeuvre, i.e. a first pivoting of the cam 4d around its rotational cam shaft 9, in order to bring the second cam lug 12 to the start of the second guide section 11b, then a movement of rotation of the second lateral guide flange 7 for the rope around its flange shaft 16.
An additional safety device can be provided in order to prevent untimely opening of the self-blocking descender-belay device 1. This then consists of providing a lock which can be activated by an unlocking button 17, the lock being arranged between the second lateral guide flange 7 for the rope and the connection body 4a. In this case, a third manoeuvre is necessary in order to ensure the unlocking, by action on the unlocking button 17, by pivoting of the cam 4d, then by pivoting of the second lateral guide flange 7 for the rope.
The structure and function of the lever 13 are now considered in relation to
This lever 13 is used when the self-blocking descender-belay device 1 is oriented as illustrated in these figures, with the coupling means 5 facing downwards, and with the braking nose 4e facing upwards. The self-blocking descender-belay device 1 is then used as a descender device, in order to brake the progression of the user's descent down the rope 3, or as a belay device in order to brake the paying-out of the rope which is retaining a climber during his descent.
The lever 13 is returned to the position of rest illustrated in
The self-blocking descender-belay device 1 is then initially in the blocking position illustrated in
Since the user is suspended by the coupling means 5, it would not be possible for him to incline the self-blocking descender-belay device 1 towards the position of release as illustrated in
In the descender function, it is then necessary to manoeuver the lever 13 in order to modify the braking on the rope 3. For this purpose, by means of the rotation of the lever 13 in the direction of the arrow 18 illustrated in
As can be seen in the figures, in the position of rest the lever 13 covers the unlocking button 17, thus forming an additional safety device to prevent the unlocking of the second lateral guide flange 7 for the rope.
In this case the closure finger 5b which is articulated on the connector body 5a according to the articulation shaft 5h comprises a locking segment 20 which extends the closure finger 5b beyond the articulation shaft 5h. In the closed position as illustrated in the figures, the second lateral guide flange 7 for the rope covers this locking segment 20, thus preventing the pivoting of the closure finger 5b towards the inner space of the connector body 5a, i.e. thus preventing the opening of the coupling means 5. By this means, the second lateral guide flange 7 for the rope itself constitutes a means for locking the coupling means 5, such that the user cannot uncouple himself until the rope has been withdrawn after pivoting of the second lateral guide flange 7 for the rope to its spaced position.
The present invention is not limited to the embodiments which have been explicitly described, but includes the various variants and generalisations contained within the scope of the following claims.
Number | Date | Country | Kind |
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13 59723 | Oct 2013 | FR | national |