FR3066396A1 - SELF-LOCKING DESCENDER FOR ROPES, FOR SETTING THE DESCENT SPEED WITH ONE HAND ACTUATING A LEVER, THE OTHER HAND REMAINING AVAILABLE - Google Patents

Abstract

Self-locking descender for ropes, to adjust the descent speed with one hand operating a joystick. The current descenders are unsuitable for the use of disparate ropes. The user must compensate for their imperfections manually. The muscular strength needed compromises safety and comfort of use. The descender presented removes these disadvantages. A cam (6) arranged in levers articulated in (35) clamps the rope against a fixed sheave (4) with a force greater than the suspended weight. It's self-locking. An articulated lever (14) is associated with the cam by a flail (8) with unequal arms, hinged at (35). A fraction of the weight is transferred to the articulation (17) of the joystick arranged in gear levers. Weighing the joystick decreases the pinching force acting on the rope; the descent begins and then accelerates if the weighing effort increases. The descender according to the invention is intended for followers of verticality wishing to keep a free hand.

Description

The present invention relates to a self-locking descender operating with a rope. The descent speed is controlled by the user by means of a gear reduction device which can be operated with one hand. No contact with the rope is necessary to descend or to stop.

This descender is intended for users who wish to manage their descent effortlessly, by having a wide range of speeds, while retaining free use of one hand. Its use will be justified during a leisure activity (speleology, mountaineering, canyoning) or during the exercise of a profession (rope access technicians, firefighters, intervention groups).

The imperfections that affect the functioning of current descenders are described and commented on in the following paragraphs.

To use a descender, you must have a moored rope. This rope hangs in the void. It is inserted into the descender attached to the user's harness. The moored strand, which enters the descender and supports the load, is called the loaded strand. The strand that comes out of the descender and hangs in the void is called the free strand. To balance the load, the free end must always be subjected to a manual restraining force. The ratio of forces existing between the loaded strand and the free strand characterizes the braking provided by the descender. Braking can be defined as the weight of the user divided by the manual restraint effort that causes the stop. Thus, a user weighing one hundred kilograms, who stops by developing a retention effort of two decanewtons (realistic value) benefits from braking worth fifty (one hundred divided by two). Note that it is possible to express this operation differently, by writing that the descender amplifies the manual restraint action. Thus two decanewtons (the restraint) multiplied by fifty (the braking) also make it possible to immobilize one hundred kilograms (the load). It is therefore the manual control of the restraining force applied to the free strand which makes it possible to adjust the descent speed, or to cause it to stop. The energy generated by the descent dissipates in the form of heat: in the descender, the rope and the hand.

Problem posed (a): in the event of a long or rapid descent, the user risks burning his hand or, at a minimum, quickly wearing his protective glove.

The diameter of the ropes usable with the same descender varies in significant proportions: usually from eight to twelve millimeters in diameter. The age of these cords, their stiffness, the presence of foreign bodies on their surface (mud, clay, sand) their degree of water imbibition, or a cord frozen to the core, profoundly modify the coefficients of friction present. In addition, a used descender will brake less effectively than a new device. The ratio existing between the weight of the user and the restraining force that must be applied to the free end to stop, will change in correlation with all these parameters. In other words: the braking developed by a descender is not constant.

As an example, take the case of a new, dry eight-millimeter-diameter rope. The sheath wires are still very smooth. The coefficient of friction available with such a rope will therefore be low. To immobilize under these conditions, the user of one hundred kilograms will have to exert a significant retaining force, for example ten decanewtons (realistic value). With this rope, the braking provided by the descender decreases to ten (one hundred divided by ten) which can be compared to the fifty mentioned above. When the braking provided by the descender is too weak, the user must compensate for this deficit manually. This requires developing a retaining effort of an intensity that is difficult to achieve or sustainably maintain. Besides the discomfort resulting from such a situation, the danger arises when the speed of descent increases until it becomes uncontrollable. At this point, if you drop the free strand, the speed of descent approaches free fall, because there is almost no active braking.

Problem posed (b): little braking imposes an excessive muscle retaining force.

We will sometimes be forced to use a used rope of large diameter, stiff, wet, fluffy, coated with clay, whose behavior in terms of friction will be fundamentally different from that found with a thin and new rope. This big used rope will no longer slide in the descender at all. Its only contact with the braking surfaces present, which have become excessive given the rope introduced, will be enough to immobilize the load without any manual restraint effort being necessary to achieve it. To get rid of cogitations relating to a division by zero - that is to say no holding force - leading to an indefinable braking value in this case, we can admit that the few hundred grams opposed to sliding by the weight of the free strand, by example five hundred grams, will calculate a realistic braking of two hundred (one hundred divided by zero point five) much greater than the weight of the user. Practical consequence: the descent is not possible.

Problem posed (c): too much braking makes the descender unusable.

The same paralysis appears when it is necessary to descend to a great height. It is then the weight of the free strand, an inevitable consequence of the long hanging rope, which will act as parasitic braking, adding to or replacing the manual restraint effort. Its value can exceed the effort to immobilize. Practical consequence: you cannot descend, unless you relieve this weight by lifting the rope. These unpleasant and tiring manipulations conceal a risk: the additional holding value, constituted by the weight of the free strand, decreases as the descent. There will come a time when it will no longer be necessary to relieve the weight of the rope, but to retain its scrolling to maintain control of a descent speed which tends to increase. The danger arises if the control of the free strand escapes the user. It is a situation where braking initially too strong can become weak, then too weak as one descends.

The manual restraint force is muscularly limited to a few decanewtons. A hand, even a muscular one, is not a vice! With a rope with a low coefficient of friction, you must be able to increase braking to maintain control of the free end. Some devices allow you to choose the braking value as soon as the rope is put in place, or to modify this value during the descent. This setting is, for example, available with descen3066396 so-called multiple-bar descenders which have fallen a long time ago in the public domain, and which, among other faults, suffer from a large footprint. With the other models, additional braking accessories must be used, external to the descender. They are most often made up of carabiners of various shapes, against which the free strand of the rope rubs or compresses, always firmly held in the hand. The correction made by these workarounds is not always sufficient to increase comfort or safety in use. The feet themselves are then mobilized to increase the friction of a rope forced to flow in contact with them! Certain assemblies lead to potentially dangerous arrangements, as they are likely to hinder the correct positioning of the descender loaded on the rope. When the latter can no longer fulfill its role initially planned, the free end becomes out of control; no more braking is possible; in this case it is the fall ...

Problem posed (d): having to increase braking with accessories external to the descender, unsuitable, improperly used, or which can become dangerous.

To increase the safety of a descender, some devices stop automatically on the rope as soon as the user releases a joystick. These descenders are said to be self-locking. We no longer risk a free fall! Locking is ensured by the rotation of a cam which clamps the rope against another braking surface. The cam is integral with a manually actuated lever; it eliminates the locking pinch to authorize the descent. The energy required to set the cam in rotation and to maintain the pinch is taken from the rope which rubs at its periphery. Remember that the friction coefficients present when using a descender are very variable. With thin and clean ropes, when the weight of the free end is insufficient to constitute significant additional braking due to the low height to descend, the friction acting on the cam is sometimes incapable of ensuring total immobilization: in this case, the descender slides more or less quickly on the rope. The wear of the surfaces allocated to pinching aggravates this tendency to slip.

Problem posed: Γ self-locking depends on the coefficient of friction relative to the surfaces present, their degree of wear and the weight of the free strand.

Self-locking is a safety device that works on an all-or-nothing basis. To descend, you must first activate the release lever with one hand, while controlling the travel of the free end of the rope with the other hand, as the instructions for use for these devices strongly recommend. ..

Problem posed (f): both hands are essential to descend.

The descenders are usually attached to the user's harness in the prone position where they thicken their template. In caving, you sometimes have to weave between two close vertical walls. This narrowness compromises the passage of the user and his descender. In this case, the technique in force consists in placing the descender at the end of a lanyard fixed to the harness, to carry it out of the user's template. Even so placed, it is not always possible to jointly manipulate the release lever and the free strand of the rope, because the narrowing of the premises prevents the necessary and simultaneous movement of the two arms. To overcome this drawback, some self-locking descenders are provided with a device intended to durably lock the blocking device. We then find ourselves with an ordinary descender, that is to say without self-locking, which works by controlling only the running of the free strand of the rope with one hand (the other arm is best arranged with the small space).

Problem posed (g): not being able to take advantage of the self-locking function in narrow areas, and especially as soon as you have crossed a tightening.

Whatever the descender model used, the rope must run against the friction surfaces provided according to a more or less complicated scheme. This is essential to guarantee self-locking and braking. It is therefore necessary to place the rope in the descender, scrupulously respecting the instructions for use supplied by the manufacturer. There are many possibilities for errors. Improper positioning can jeopardize the safety of the user who hangs on a device in which the rope is incorrectly placed.

Problem posed (h): the risks of malfunction linked to an incorrect installation of the rope in the descender.

The analysis of the causes of accidents finally reveals that it is possible to start to descend on a poorly closed device ... The rope can then escape. In this case it's falling!

Problem posed (i): start to descend with an improperly closed descender Summary of the employment or safety problems highlighted:

a) - Burning of hands, wear of gloves;

b) - Little braking imposes excessive muscular force;

c) - Too much braking makes the descender unusable;

d) - Obligation to use additional braking accessories;

e) - The self-locking depends on the coefficients of friction and the weight of the free strand;

f) - Both hands are necessary to descend with a self-locking descender;

g) - No self-locking available in narrow passages;

h) - Incorrect insertion of the rope into the device;

i) - Ability to descend with an improperly closed device.

The following paragraphs discuss the faults which affect certain descenders, but which are absent from other models. The corrective provisions for these anomalies are old and are now in the public domain. However, they appear to be qualities which must be provided with a device reputed to be innovative and are cited here for the record.

If the joystick released in the self-locking position overflows from the body of the device, the user risks inadvertently actuating it, if only temporarily, while working during a stop. The blocking disappears immediately and the surprised user descends suddenly several meters before reacting so that the descender stops again.

(j) - To avoid this drawback, some descenders have a handle that can be locked in position during a stop, or that can be folded down automatically as soon as the user releases it.

When the descent is carried out on a rope which has a low coefficient of friction, it is difficult to manually limit its speed due to the intensity of the effort to be exerted on the free strand. With a self-locking descender, it is tempting to increase braking by releasing the blocking lever, or even to manually force its rotation in the direction which causes biocage. Pinching the rope between two flat surfaces, this auxiliary braking causes the flattening of the rope which loses its circular section.

(k) - Some descenders correct this flattening by forcing the loaded rope to pass through a V-shaped groove (vee) which restores circularity.

To introduce the rope into a descender, it is often necessary to open it. This opening, the installation of the rope, then the closing, must be able to operate without detaching the descender from the roping harness. Some devices must be detached from the harness to introduce the rope. There is a risk of escaping them and losing them during these manipulations. A falling descender can also cause injury if someone is in its path.

(l) - A descender must be captive during the installation or removal of the rope.

To summarize, we note that the main problem posed by current descenders comes from the obligation made to the user to ensure the control of the free strand of the rope with his only muscular force, forced to operate with available braking is too weak (discomfort and danger) is too high (thwarted or impossible descent).

The descender according to the invention makes it possible to remedy in an innovative manner the problems posed, summarized in the paragraphs marked (a) to (i). It incorporates the qualitative provisions, in the public domain, described in the paragraphs identified (j) (k) and (1). Finally, it offers a useful feature for belaying climbers, marked (m).

The descender consists of two flanges assembled on either side of two circular sheaves, immobilized in rotation, fixed on the flanges at each of their ends. Each flange is pierced with a hole, aligned on their long axis, approximately located in the middle, and which will be called median hole for simplification of vocabulary. Considered according to the direction of descent, there is a high sheave, positioned at the upper end of the flanges, and a low sheave, positioned at the lower end. The high sheave comes into contact with the loaded strand of the rope. It has a perimeter groove whose cross section, V-shaped (vee), is wide and deep enough to receive, between its sides, the half-section of the rope of larger usable diameter. The low sheave comes into contact with the free end of the rope. It has a perimeter groove whose cross section, of shallow depth, is round. The total width of the sheaves is compatible with the rope of larger usable diameter, without the latter coming into contact with the framing holding or guiding pieces during its scrolling during descent.

The flanges assembled on either side of the sheaves, top and bottom, have between them a space equal to the width of the sheaves. This space is used to receive the various elements necessary for the functioning of the descender. To make it easier to understand the innovative devices described, a breakdown into separate functional elements is adopted to facilitate their description: introduction and removal of the rope, braking, self-locking, job security, descent control device, special features of the controller, belaying of a climber and closing device adopted.

Introduction and removal of the rope. A medial sheaf has a perimeter groove whose cross section, of shallow depth, is round. The median sheave is immobilized in rotation and in translation on a connecting rod articulated at the level of the low sheave. The median sheave has a hole in the center. The connecting rod is also pierced with a hole aligned with that of the median sheave. These holes, of a diameter suitable for the desired shear strength, allow the introduction of a closing device (for example a pin) which is inserted simultaneously in the median hole of the two flanges, the central hole of the median sheave and that of the connecting rod. This assembly, which can be described as mobile equipment, is immobilized between the support flanges. When the closing device is removed, the connecting rod and medial sheave can pivot around the low sheave, which has a journal allowing the free rotation of the connecting rod despite the tightening of the flanges against the sheaves. This rotation releases the median sheave from the grip of the flanges. The space freed up between the support flange opposite the connecting rod and the middle sheave allows the introduction of the larger diameter rope intended for use with the descender. To increase the convenience of placing the rope, the descent control device (which will be described later) acts as a stop limiting the rotation of the assembly, connecting rod and medial sheave, as soon as the space allowing 'introduce the rope is obtained. The installation is carried out on the rope which hangs in the void, without having to touch the rope itself. This reduces the risk of installation errors. When closing the assembly: connecting rod, medial sheave, all the holes participating in the closing device must be placed in coincidence to facilitate the insertion of the pin. To achieve this, the connecting rod is abutted as soon as this coincidence is ensured. The stop is obtained by the contact of the rod with the high sheave. To facilitate the evacuation of dirt always possible (clay) the contact area between the connecting rod and the top sheave is locally thinned; it is further profiled to allow their evacuation. The end of the connecting rod is arranged to be actuated by the user with a finger. By pressing on this end you activate a lever. The engine lever arm, on which the finger acts, corresponds to the length: center of the bottom sheave, end of the connecting rod. The resistant lever arm, on which the rope to be placed reacts, corresponds to the length: center of the low sheave, center of the middle sheave. In this arrangement, the motor lever is larger than the resistant lever. The manual effort required to close the descender is amplified in the ratio of the lever arms present. The introduction of the rope between the top and bottom sheaves is facilitated.

Braking. At this stage of the description, we see that the cord in place is deflected by the middle sheave between the high sheave and the low sheave. There are therefore three friction surfaces representative of the braking offered by the descender. The diameter of the median sheave, and its insertion angle between the high and low sheaves, is chosen so as to be suitable for the overall braking sought. Given the moderately winding path of the rope in place against the three fixed sheaves, the available intrinsic braking is weak. This avoids malfunctions linked to the different ropes used (diameters, stiffness, surface condition, frost). This deliberately reduced braking is associated with a high retaining force of the free strand to immobilize the load. This high effort comes from the self-locking device described below.

Auto-lock. The medial sheave is provided with two lateral pins on which a cam is articulated, fixed between two flanges which allow it to pivot concentrically with the medial sheave. One of the flanges can be attached to the cam (single piece). But the flange which is opposite it must be removable in order to be housed between the median sheave and the connecting rod which holds it laterally. The trunnion has sufficient lateral play to leave this articulation free despite the immobilization of the median sheave against the connecting rod. This arrangement fixes the cam and its flanges on the mobile assembly already described. Remember that this assembly pivots to allow the introduction of the rope into the descender. At a distance from the axis of rotation of the cam, the latter is pierced with a hole allowing the passage of a carabiner hooked to the user's harness. Given the mode of introduction of the rope, already described, we note that it is not necessary to unhook the carabiner from the harness, or the descender, to introduce the rope. The descender is captive. When rotated by the suspended load, the cam pivots to pinch the free end of the rope against the bottom sheave. Pinching causes a punctual flattening of the rope, compressed between cam and low sheave. This flattening value under a given load varies according to the strings and their diameter. When the low sheave is circular, the plucked string undergoes a punctual necking on contact. To save the resistance of a soft or small diameter rope, especially in the event of an impact, the low sheave can be replaced by a shoe with a greater radius of curvature in line with the nip required for blocking. The pinched length of the rope will then be greater. The profile of this pad may be symmetrical to that of the cam. The absence of punctual necking improves the scrolling of the rope during the descent. The curvature of the pinch area of the cam and the circumference at the bottom of the throat of the median sheave are positioned in such a way that the cord simultaneously tangents these two curves. This arrangement favors the soft sliding of the rope during the descent by avoiding parasitic sinuosities.

Suppose the system immobilized by the pinch caused. The load is then suspended on the moored rope. The rope is inserted into the throat of the top sheave and is supported there. The axis of the rope and the hooking point of the carabiner supporting the load are perfectly aligned along the vertical. The axis of rotation of the cam, the zone of pinching of the rope and the point of attachment of the user are arranged to constitute a lever. The engine lever arm corresponds to the length: axis of rotation of the cam, hole for hooking the load, added horizontally. The driving force is the weight of the user. The resistant lever arm corresponds to the Ion3066396 poeur: axis of rotation of the cam, pinch point of the rope against the skate or the low sheave, reported along the perpendicular to the tangent at the point of contact. In this configuration, the motor lever is larger than the resistant lever. The gripping force acting on the free end of the rope will be greater than the value of the suspended load represented by the weight of the user. A high holding force supplants manual control involving muscular force: the free strand of the rope does not need to be maintained. It also dispenses with the need for high intrinsic braking. To immobilize the suspended load and therefore achieve self-locking, it suffices to set an adequate ratio between: the levers involved, the load, the braking available and the rope used.

Work security. To install the rope in the descender, simply remove the closing device (pin) and then rotate the connecting rod supporting the moving part, now made up of the middle sheave and the cam articulated on its flanges. Unlike existing devices, it is the descender that is placed on the hanging rope - without having to touch it - and not the rope that must be introduced into the descender, scrupulously respecting the required sinuosities. The only possible error would be to place the descender upside down on the rope. In this hypothesis, the self-locking would be ineffective and the intrinsic braking insufficient to limit the speed of descent, which would then be akin to a fall, which no manual effort to hold the free strand could control. To eliminate this risk, the cam is provided with a boss, profiled to be introduced between the sides of the V-shaped groove (vee) of the top sheave (which becomes sheave from the bottom as a result of being turned upside down). When the cam pivots while the descender is placed upside down, the penetration of the boss into the V-shaped groove (vee) of the sheave is planned to pinch the rope of smaller usable diameter. If suspended on the descender placed upside down, this boss causes self-locking. The active lever arms, the load and the resulting gripping force are of the same function as that described above. The user can no longer do anything except ... place the descender in place!

Descent control device. The removable cam flange, articulated between the central sheave and the connecting rod, and designed to receive a joystick, operable with one hand, intended to control the descent. The action on the lever requests a multiplied device which gradually relieves the action of the load, by reducing the intensity of the pinching force which causes self-locking. When the gripping force decreases, the free strand of the rope begins to slide, the descent begins. The cam flange supporting the lever behaves like a balance. The axis of rotation of the beam is the same as that of the cam, but this axis is not in the middle of the beam thus formed. This determines two lever arms of different lengths. The shortest motor lever arm supports the load; its value is the length, compared to the horizontal: axis of rotation of the beam, hole for suspension of the load. The longest resistant lever arm has the value of the length, referred to the horizontal: axis of rotation of the beam, axis of rotation of the control lever. The weight applied by the load and its reaction on the other branch of the beam are in the same direction (the vertical) in opposite directions (load down, reaction up) but of equal intensities in3066396, in proportion to the arms of relative levers involved. The reaction load to be relieved to descend is lower than the supported load; this constitutes a first reduction. This reaction force is applied to the axis of rotation of the control handle which behaves like a lever. The shortest, resistant lever arm has the value of the length, compared to the horizontal: axis of rotation of the lever, fixed fulcrum. The fulcrum is provided by an appendage to the connecting rod against which a protuberance of the control lever comes to bear when it is actuated. The assembly: control lever, cam flange and fulcrum is arranged so that it is necessary to weigh down on the control handle to descend. The longest engine lever arm corresponds to the total length of the control lever resting on the fixed point of the connecting rod. Bringing this length horizontally is not essential here; the maneuver is freed from gravity, because the hand can act in the direction that suits it best. Starting from a self-locking situation, the resistant lever arm of the control handle in contact with the fulcrum, has a length reduced to the minimum compatible with the geometry of the parts present: diameter of the hinge pins , variations linked to the different diameters of the usable ropes, mechanical strengths required for assemblies. This makes it possible to start the descent by actuating the lever with a minimum force, the quantified value of which depends on the overall reduction ratio presented by the play of the various levers intended to relieve the load. It is interesting to note that the value of the load suspended from the hooking carabiner decreases as soon as the user actuates the control handle. By weighing on the joystick he transfers a part (admittedly moderate) of his own weight to the joystick. This weighing modifies the balance of the descender, apprehended according to the vertical, until the equality of the moments: reduced load, related to the axis of the rope and weighed on the lever, related to the axis of the rope be restored. As the user presses the joystick the angle of rotation increases. The cam rotates in turn, by a lesser angle than that of the lever due to the available reduction ratio, and moves away from the low sheave. The concomitant pinching of the rope decreases. The descent begins. The descent speed accelerates when the load on the joystick increases. The protuberance of the lever in contact with the fulcrum on the connecting rod is arranged so that the length of the resistant lever arm lengthens as the angle of rotation of the lever increases. This elongation is made possible by the sliding of the projection of the control handle against the appendage of the connecting rod. All other things being equal, an increasing effort must therefore be exerted on the joystick to increase the speed of descent. It is a safety device which avoids unintentionally triggering a suddenly excessive descent speed, without eliminating the possibility of having recourse to it. Increasing the descent speed requires voluntary action, since the force to be applied to the control lever is increasing. This makes it possible to have a wide range of usable speeds: from the slowest, when the sliding of the rope begins with the lessening of the toe, to the faster, when the pinching force tends towards zero and that the speed n 'is more limited than by the friction of the rope against the sheaves. If the force applied to the control lever is reduced, the speed is reduced; if we release it, we stop.

It should be clarified why the median braking sheave must be dissociated from the cam which revolves around its center. During the descent, the rope runs against the middle sheave from bottom to top. The friction caused generates a tangential force which tends to drive it in the same direction of rotation as the cam which causes the rope to be pinched. If sheave and cam made up a single part, the friction due to the descent would tend to engage the cam in rotation in the direction of the pinch. This parasitic rotation would add to the weight of the suspended load. The action on the control lever would be inappropriately hardened, and each variation in friction of the rope on the cam-sheave would be reflected in the value of the rope's nip. The joystick would become impossible to control with precision and the descent would be unpleasantly interspersed with dead ends.

Special features of the joystick. To facilitate gripping and increase comfort of use, the control handle is slightly curved and has thickness. The thickness is obtained by adding a spacer inserted between two pieces. The first part concerns the control lever, as described above, which acts as a lever. The second part, which we will call counter-joystick, presents a cut similar to the first. It is articulated on the same axis as the control lever, but does not have a protrusion for use as a lever. Control lever, spacer and counter-lever are assembled and constitute the lever apprehended in its entirety, actuated by the user to descend. The spacer does not fill the entire length of the space separating the control handle and counter-handle. This makes it possible to incorporate a torsion spring around the axis of rotation common to these two elements. One end of the spring bears on the cam flange. The other end of the spring rests on the counter-lever. The spring is mounted with an initial tension between its two supports so that the lever is permanently applied in contact with the high sheave when the descender is not used. The abutment of the lever against the high sheave causes, by reaction of the spring on the cam flange, the rotation of the cam flange and of all the members attached to it. When the cam flange comes up against the low sheave, the descender is folded back. Its size, then reduced to the minimum possible, corresponds to the state in which it is intended to transport it, for example to the belt of the harness, by means of the carabiner inserted in the hooking hole of the cam. The pre-tensioned spring is sufficient to keep the assembly folded. The spring is wound in a direction which increases its tension when the user actuates the lever to descend. If the user releases the lever, the spring relaxes and causes it to fold back. The lever retracts and abuts against the loaded rope. This prevents inadvertent actuation of the joystick during a stop.

Remote control. At the end of the joystick, and opposite its articulation axis, a hole is drilled which crosses: control joystick, spacer and counter-joystick. The diameter of this orifice and the total thickness of the handle allow the passage of a carabiner in which one can introduce an auxiliary link, intended to actuate the handle remotely. For a speleologist he is forced to cross a narrowness, this remote control makes it possible to deport the descender out of his body size (by putting at the end of the lanyard) then to pull manually on the cord to control the descent. For a user who temporarily needs to have both hands, it is possible to descend by actuating the remote control, with an appropriate strap, secured to a thigh or a foot. Remote action would be compromised by folding the joystick against the loaded rope. In this particular use case, the lever must remain unfolded so that the remote traction remains effective along the vertical. A rotary holding latch, which can be operated with a single finger, even in the event of a descent or stop in suspension, enables the automatic folding of the joystick to be paralyzed. One of the ends of the lever spring presses the latch which has a boss concentric with its axis of rotation. The boss operating with the spring determines two stable states separated by a neutral point. Under the thrust of the spring, which acts beyond neutral to the first stable state, the unused latch remains in place in a notch in the counter-lever. To activate the latch, it must be pivoted with a finger, acting on an overhanging protuberance formed at the end opposite its axis of rotation. Under the thrust, the boss compresses the torsion spring. When the neutral point is exceeded, the spring completes the rotation until the second stable state, where a feeler comes into contact with a curved angular sector, with the same center as the axis of rotation of the lever, cut out on the edge of the cam flange. When the user actuates the lever, the spring keeps the probe and the latch in contact with the curved sector. The cam flange has a notch connected to the curvature of the sector on which the probe rubs. When the lever is released, it tends to fold back under the action of the lever spring. In this withdrawal movement, the probe traverses the curved sector of the cam flange and engages in the notch where it comes into abutment: the withdrawal of the lever is stopped. The notch is placed on the cam flange so that the activated latch does not disturb the reduction of the lever, nor the self-locking and that it can be operated regardless of the diameter of the rope used.

The description of operation of the joystick completed, it is necessary to return to the device for placing the rope, the full description of which remains pending. The connecting rod and everything attached to it: median sheave, cam, flanges, complete lever, latch and assembly elements, pivots around the low sheave to introduce or remove the rope. This rotation is made possible because all the elements connected to the connecting rod are dimensioned so that they pass between the two flanges enclosing the top and bottom sheaves as soon as the closing member is removed to introduce the rope into the descender. In this rotational movement of the connecting rod, the lever pressing against the high sheave pivots, slides, then engages between the flanges. When the space cleared between the flange and the medial sheave is reached to introduce the rope of larger usable diameter, the abutment stops of the ends of the torsion spring come into contact with one another. The cam flange and the lever are no longer articulated. The rigidity concomitant with this contacting of the stops immobilizes the rotational movement of the connecting rod, stopped by the lever in contact with the high sheave. The rope can be inserted without difficulty. Finally, it should be noted that the abutment of the joystick and the cam flange activates similarly when the joystick is pressed fully to reach a high descent speed.

Belaying of a climber. A mountaineer practicing climbing at the head of the rope ensures his progression with a rope which slides in carabiners hung on moorings fixed step by step in the wall. From a so-called relay point, the second of the rope assists the climber by means of the rope that joins them together. Four different actions must be able to be carried out by the second. One: allow the rope to run freely during the ascent. Two: immobilize the climber's fall by intercepting the resulting impact force. Three: lower the climber to the relay if he cannot resume his progress. Four: at his request, keep the climber suspended on the rope by counterweighting. Various specialized devices allow all these belaying actions to be carried out. The descender according to the invention also allows it in an original way.

Action one: the rope is introduced into the descender in the same way as for the descent. The initially said strand loaded becomes the climbing strand of the climber. The free strand retains its name, but it must be introduced into the hanger of the carabiner attached to the harness of the second roped party, or on a fixed anchor point of appropriate strength, so that the descender in belay position is positioned properly . The loaded strand and the free strand are held manually; you don't touch the device. In the current configuration, we can not pretend to the free scrolling of the rope to give slack to the climber, because the tether, manually pulled, takes support against the high sheave. This support causes the immediate rotation of the cam fixed to the harness of the second by a carabiner and initiates the pinching of the rope which comes to a standstill between cam and low sheave. Solution: the return force of the lever spring is used in conjunction with a rotary latch, placed on the counter-lever, intended to delay the rotation of the cam and therefore to delay the pinch which leads to self-locking. The rotary latch can take several positions. A so-called rest position in which it is inoperative and a so-called belay position in which it overflows from the template of the lever to stall under the high sheave. When the belay latch is activated, the hand holding the tether strand pulls on the rope to give slack. The hand holding the free strand facilitates this movement by accompanying the rope that enters between the cam and the bottom sheave. Under the action of the lever spring, the belay latch remains in abutment under the high sheave. This device causes an operating threshold below which self-locking is inhibited. The belay latch in abutment under the high sheave is positioned in such a way that it preserves a space between the cam and the low sheave so that the rope of larger usable diameter slides there freely.

Action two: to immobilize a climber who falls, it is enough for the second of the rope to exert a weak force of retention on the free strand of the rope to suppress its running. When the free strand of the rope is immobilized and when the tether strand tightens under the force generated by the fall, the belay latch in contact with the high sheave pushes the lever and bypasses the high sheave. The belay latch loses its role as a stop. Cam rotation becomes possible again. The space provided for the passage of the rope between cam and low sheave is shrinking. Self-locking is reactivated. The fall of the climber is intercepted.

Action three: if the climber hanging from the end of the rope cannot resume his ascent, the second only has to activate the joystick to lower him to the level of the relay. There is no point in keeping the strand free.

Action four: to counterbalance the tether rope, the second must alternate the movements applied to the two strands of the rope. Simultaneous traction on the tether strand and on the free strand recovers the slack. By releasing the attachment strand, but keeping the strand free, we find self-locking; the second is enough to bend the knees to counterbalance. Pulling back on the tether strand and the free strand removes the self-locking. During these successive gestural alternations, the travel of the belay latch around the high sheave is adjusted to regain the automatic rearming of the device, that is to say the return to setting of the latch under the high sheave, without having to touch to the joystick. This allows to quickly chain, if necessary, the successive movements of catching the slack and applying the counterweight.

Belay latch activation mechanism. The spacer of the handle is pierced with a circular hole on which opens and connects a blind rectilinear light at its other end. The control lever and the counter-lever are each drilled with a smaller hole, aligned with the center of that of the spacer. The circular hole of the spacer receives a hexagonal section shaft, provided on either side with pins for use as a rotation axis when they are introduced into the holes made on the control lever and the counter-lever. A compression spring engages in the lumen of the spacer. One end of the spring takes support at the bottom of the blind light. The other end of the spring is provided with a feeler inserted between a few terminal turns. The probe provides interface contact with the spring and the hexagonal part of the rotor. The hexagonal section of the rotor is larger than that of the pins which allow free rotation. Notwithstanding the presence of the games essential to the movements, the rotating hexagonal piece is immobilized in translation as soon as the control lever and the counter-lever are assembled on either side of the spacer. The spring is trapped in the light where it is inserted. By pressing on one side of the hexagon, the spring mounted in the lumen with an initial compression allows it to keep the rotor in a stable position every 60 °. The belay latch is fixed at the end of the rotor shaft on the side of the counter-lever. The assembly device selected secures the rotor and the latch in rotation. The cut and position of the latch fixed to the rotor is defined so that it comes to bear under the high sheave as soon as the space freed up between cam and low sheave allows the free sliding of the rope of larger usable diameter. A stop integral with the lever holds the belay latch in support under the high sheave. This redundancy with the action of the internal spring perpetuates the exact position of the belay latch in service under the high sheave. The rest position is obtained by turning the latch with a finger. The rotation causes the compression of the spring on the passage of each of the edges separating the faces of the hexagon, then its relaxation. After a rotation of 300 ° the latch reaches its rest position. It stabilizes there under the action of the spring. Rotation is no longer possible beyond 300 ° because it comes into contact with the stop integral with the lever. This large angle of rotation avoids inadvertently activating the belay latch and allows it to fully retract into the template of the joystick when the descender is used to descend.

Closure of the descender. The descender must be able to be conveniently closed and then opened to put the rope in place and remove it. This causes multiple maneuvers which should be facilitated. A simple locking pin, for example a commercially available ball pin, made captive by a flexible link attached to the body of the descender, constitutes a possible closure method, but inconvenient to handle, and which does not meet all the criteria for required safety, in particular the certainty of its correct locking in the closed position. The efficient closing device proposed for the descender which is the subject of the invention allows convenient handling and satisfies the quality and safety constraints required for this type of material.

Mechanical resistance. The rod acting as a pin is inserted between the support flanges of the top and bottom sheaves. It immobilizes the rotation of the mobile assembly assembled on the connecting rod. It suffices to calculate the section appropriate to the characteristics of the constituent material chosen so that the pin resists the double shear to which it is subjected during the application of the forces generated by use, including the safety coefficient.

Handling. In the open position, the pin must free the moving assembly from its grip. To do this, it slides simultaneously in the median hole of the support flange and in a hole drilled in an external guide extending beyond the flange on the side where the withdrawal is made. When the pin arrives in the open position, the overhanging outer guide maintains the alignment of the pin with the holes of the moving element and of the flange located opposite. The pin has a shallow mortise, hollowed out using a generator. The width of the mortise allows a rod which is perpendicular to it, thanks to a drilling carried out in the overhanging guide, to slide in contact with it. This perpendicular rod will constitute a lock. The two ends of the mortise act as limit switches by stopping the movement of the guided pin when they come into contact with the bolt rod. This mortise operating with the bolt rod which slides there makes the pin captive. When the pin is in the open position the lock rod abuts against one end of the mortise. In this withdrawn position, the end of the pin is flush with the inside of the support flange and allows the free rotation of the mobile assembly. You can open the descender to insert the rope. When the pin is pushed into the closed position, the lock rod abuts against the other end of the mortise. A hole drilled there, at the bottom of the mortise, gives way to the bolt rod. The hole passes entirely through the pin, outside of the zone constrained by shearing. It allows dirt, possibly deposited at the bottom of the mortise, when the pin is pulled, to be evacuated through it by the bolt rod. As soon as the lock rod enters the hole, the pin is locked in the closed position. The end of the pin, which slides through the holes of the mobile assembly and the shear support flanges, protrudes when it is in the closed position. This slight protuberance ensures correct support of the pin against the flange, possibly ribbed, which reacts to the shearing force; it will also be used to cause the withdrawal of the pin before opening of the moving assembly. The bolt rod is guided in its movement by a sheet bent at right angles, pierced, fixed on the overhanging guide and the flange. A spring operating under compression is threaded onto the lock rod. One of the ends of the spring bears against the folded sheet. The other end of the spring is supported on a collar projecting from the lock rod. The spring is slightly compressed between folded sheet and collar when the bolt rod is introduced into the mortise. The friction caused allows the pin to maintain the position in which the user places it. Most often it will be in the open position. The bolt rod protrudes from the sheet metal which guides it. This same sheet protects the control spring and the rod from external aggressions, in particular during the transport of the descender. The end of the rod and provided with a gripping pallet operable with a finger, for example a thumb, either that of the right hand or that of the left hand. You can also grasp this palette between your thumb and forefinger, regardless of the hand. The amplitude of movement of the lock is limited by the abutment of the gripping pallet against an element for assembling the flanges on the high sheave. The gripping pallet rubs against the support flange when it is operated. This prohibits any possibility of parasitic rotation and perpetuates the convenience of gripping the pallet. Last arrangement, the guided pin is provided with a short gripping rod incorporated at the end opposite to that which slides in the various holes allowing the closing of the descender.

These constructive arrangements lead to the following operation. To open the descender, it is enough to exert a light pressure with a finger, for example the index finger, on the end of the pin which protrudes from the support flange. At the same time, the lock is opened by operating the grip pallet with a thumb of the other hand. As soon as the bolt rod comes out of the hole drilled in the bottom of the mortise, the pin is ejected by the push applied at its end by the finger. The clearance between the bottom of the mortise and the bolt rod allows the pin to slide freely until it stops at the bottom of the mortise. As soon as the grip pallet is released, the spring presses the rod against the bottom of the mortise. This pressure is enough to immobilize the pin in the position where it is located. If it has not reached the stop allowing the opening, the maneuver must be completed by pulling on the gripping rod provided at its end. When the rope is in place and the holes of the moving part are in coincidence, it is enough to push back the pin to close the descender. As soon as it reaches the end of its travel, the bolt is automatically inserted into the hole in the mortise under the pressure of the spring. This closure produces an audible click guaranteeing locking. A visual cue is also planned. Between the gripping pallet of the engaged lock and the means of assembling the flanges on the high sheave is placed a visual reference. When the lock is removed, this mark is hidden by the rod. When the lock is engaged, the mark is visible.

Descender kept open. The assembly means allowing the articulation of the unfolded retaining latch of the lever, makes it possible to force the descender to remain open when it is used in association with the guided closing pin. When the rotation of the mobile assembly articulated around the connecting rod is immobilized by the contact of the lever and the high sheave, it is possible to partially push back the guided closing pin. The end of the pin is inserted between the assembly means for use as a hinge pin and the protuberance enabling it to be activated or put to rest. The abutment of the guided pin with the overhang of the hinged assembly means of the latch keeps the moving assembly in the open position. This arrangement can be useful when the rope to be put in place is difficult to access or when the user is in an acrobatic position. It is then convenient to open the descender beforehand with both hands, then leave it open before accessing the rope. This operation of keeping the mobile assembly in the open position remains functional whatever the preexisting state of the holding latch: either at rest or activated. After insertion of the rope, a slight withdrawal of the guided pin, exerted by grasping the gripping rod provided at its end, frees the mobile assembly which can be closed. The user can even push the pin back by pressing the descender against him: ventral control!

Choice of free hand. The pin and its guiding and locking device are assembled on one of the support flanges of the top and bottom sheaves. The two flanges are identical. It is possible to swap them. A right-handed user will be satisfied to operate the joystick controlling the descent with the right hand, unless he prefers to keep his right hand free ... A left-handed user will be satisfied to actuate the joystick controlling the descent with the left hand , unless he prefers to keep his left hand free ... Being able to swap the flanges allows this choice of use, which can be defined during the assembly of the descender. The advantage of this possible permutation lies in the fact that the guided pin and the effective locking visual reference always face the user, whatever hand is chosen for the maneuver.

The guided captive pin described therefore has all the desired qualities: shear strength, captivity, ease of handling, speed of opening, speed of closing, verification of effective locking in the closed position by audible and visual indicators, convenience of handling in delicate situations , choice of descent control hand.

The figures appended hereto are taken from the plans used to build the prototype, which made it possible to test and validate the innovative ideas mentioned.

Figure 1 shows the descender object of the invention. It is deliberately reduced to its only main components: phantom view of the load self-locking and action on a joystick to control the descent speed.

Figure 2 shows the path followed by the rope in place in the descender, as well as the forces and levers involved to obtain self-locking by pinching the rope between the cam and the bottom sheave. The released lever folds up against the rope.

Figure 3 offers a variant intended to replace the low sheave with a shoe with a larger radius of curvature to the right of the toe of the rope.

FIG. 4 represents the levers involved by the lever multiplier device, which makes it possible to gradually decrease the gripping force applied to the rope to descend.

Figure 5 shows the descender in the open position, ready to be placed on the hanging rope.

Figure 6 shows the safety device automatically activated if the descender is mistakenly placed upside down on the rope, the forces and levers present to ensure self-locking and concomitant inhibition of the joystick.

Figure 7 shows the latch that holds the handle unfolded; this allows remote control of the descender by means of a cord hung in the hole provided.

FIG. 8 specifies the operation of the latch examined in its role of feeler.

Figure 9 shows how the automatic folding of the handle, permanently stressed by a spring, reduces the size of the descender during transport.

Figure 10 shows how the descender can be used from the bottom as a belay device for a climber progressing in climbing.

Figure 11 shows how the descender, still used from below, immobilizes the rope in the event of the climber falling.

Figures 12, 13 and 14 detail the stages of operation of the mechanism incorporated in the handle, allowing the belay latch to be put into service or to be replaced at rest.

Figure 15 shows the guided captive locking pin and its associated mechanism in the open position; the descender can be opened to insert or remove the rope.

Figure 16 details the constituent elements of the guided pin.

FIG. 17 represents a front view of the flange supporting the device for controlling the guided pin in the open position.

FIG. 18 shows the guided captive locking pin and its associated mechanism in the closed and locked position; the descender cannot be opened.

FIG. 19 represents a front view of the flange supporting the device for controlling the guided pin in the closed, locked position, with its visual indicator of correct operation.

FIG. 20 shows that the guided captive pin, its associated mechanism and the support flange, can be assembled facing a user who prefers to operate the lever with his right hand.

FIG. 21 shows that the guided captive pin, its associated mechanism and the support flange, can be assembled facing a user who prefers to actuate the lever with his left hand.

Referring to Figure 1, we discover a general view of the descender, reduced to its two essential functions: self-locking and control of the descent. A phantom view of the device leading to the self-locking of the load, materialized by the suspended weight of the user, highlights a cam (6) arranged in levers, articulated in (35), which clamps the rope against a fixed sheave (4) with a force greater than the suspended weight. An articulated lever (14) is associated with the cam by a beam (8) with unequal arms, articulated at (35). The unevenness of the lever arms made up means that a reduced fraction of the weight of the user can be transferred to the articulation of the lever (17) arranged as lever multipliers. Gradually weighing on the handle decreases the gripping force acting on the rope; the descent begins at reduced speed, without the need to keep the strand free. The descent speed increases as the weighing effort on the joystick also increases. Releasing the joystick causes the descent to stop immediately, as there is self-locking.

Referring to Figure 2, we observe the path followed by the rope (40) in place in the descender. By convention, this figure can be qualified as a front view when the control lever is located on the right hand. Some of the constituent parts do not appear on the drawing which is limited to showing the elements involved in the following functional description.

The high sheave (3) and the low sheave (4) are assembled by screwing onto the support flange (1). The sheave fixing hole is threaded. This arrangement is sufficient to immobilize in rotation the sheaves bolted to the flanges when they are stressed by friction consecutive to the running of the rope. Sheaves can also have a smooth hole. Immobilization in rotation can then be ensured by one of the many existing mechanical devices to achieve the same result. The cam (6) is fixed by screwing on the removable cam flange (8) supporting the handle (12). The median sheave (5) centered on the through hole (5.3) of a closing pin (not shown) is immobilized in rotation by a device described in FIG. 4; it has, on each of its sides, a pin (5.2) for articulation of the cam flanges. This articulation makes the cam and its flanges movable in rotation. One of the cam flanges is not shown. This flange can be attached to the cam by screwing (the prototype) or be an integral part of the cam articulated on the journal (5.2). The user of weight P hangs from the descender by a carabiner inserted into the hole (6.3) of the cam. Applying the weight P into the hole (6.3) loads the moored rope (40). The load P causes the rotation of the cam and its flanges around the pins (5.2). The cam (6) clamps the rope which flattens a little against the bottom sheave (4) preventing it from scrolling. The load is immobilized. In this position, the axis of the rope and the point of application of the load are perfectly aligned along the vertical. This system involves a system of levers. The motor lever Lp is actuated by the load P. The resistant lever La allows a force Fa to be applied to the plucked rope. As by construction Lp is larger than La, Fa will be greater than P according to the relationship:

The

Fa represents the force which ensures the self-locking of the load. It is enough to adjust, geometrically speaking, the value of the levers Lp and La so that the self-locking works with the rope of smaller diameter intended to be used with the descender. Tests show that self-locking is ensured with a rope eight millimeters in diameter when Fa is 160% of P. With a rope of larger diameter, the flattening of the plucked rope will be less than with a thin rope . Consequently, the angle of rotation of the loaded cam will be reduced. The balance of the descender on the rope will be slightly modified. The length of the engine lever arm Lp relative to the horizontal will be slightly increased. There is almost no variation. With a rope 11 millimeters in diameter, the calculation based on the measurement of the length of the levers, as they appear in position on the plane, gives for Fa a value equal to 180% of P. Conclusion: the self- correctly adjusted blocking for a thin rope will continue to be functional with a larger diameter rope. With a free strand immobilized by a force worth 160% of P if P is worth one hundred kilograms, the free strand will be controlled by one hundred and sixty decanewtons. This value must be compared to the ten decanewtons painfully obtained manually with the existing descenders ... Practical consequences: it is no longer necessary to have a string of windings described against many friction surfaces to obtain substantial braking. There is also no need to add external braking devices to the descender. The reduced intrinsic braking of the descender which is the subject of the invention is ensured by the almost linear path of the rope rubbing only against the high sheave, the low sheave where the rope is plucked, and the middle sheave. This light braking, operating with a high retaining force of the free strand, is sufficient to immobilize the suspended load.

This innovative arrangement corrects the problems posed: (b) little braking, (c) too much braking, (d) additional accessories and (e) friction-dependent self-locking.

The joystick that the user manipulates consists of three assembled elements: lever joystick (12), spacer (13) and counter-joystick (14) which appears alone in the figure. The lever is articulated on the cam flange (8) by the assembly bolt (15) forming an axis of rotation. A torsion spring (18) is mounted around the axis (15) in the space provided by the spacer between the parts (12) and (13) constituting the lever. One end of the spring bears on the screw (33) integral with the cam flange (8). The other end of the spring rests on the assembly screw (20) secured to the counter-lever (14). The spring is mounted between its supports with an initial tension which tends to bring the lever, considered according to its three assembled elements, against the rope as soon as the user releases it.

This arrangement satisfies the required quality (j) automatic folding of the joystick, already present on other descenders.

With reference to FIG. 3, a construction variant is proposed which consists in replacing the low (circular) sheave by a shoe (4.2) which has a greater radius of curvature at the level of the cord pinched by the cam (6). A large radius of curvature is less restrictive for the rope. The shoe can be immobilized in rotation by an internal thread (like sheaves) or by any other already existing device.

Referring to Figure 4, there is a rear view of the descender, the joystick of which is actuated by the user with his right hand. The flange initially identified (1) and the assembly bolts do not appear on the drawing which is limited to showing the parts involved in the functional description.

The sheaves (3) and (4) are screwed onto the support flange (2). The descender is shown in a self-locking situation. The rope (40) is in contact with the top (3), middle (hidden) and bottom (4) sheaves. The connecting rod (10) articulated on the pin (4.1) cut on the low sheave or on an attached ring (4.3) shows the fixing screws (11) of the median sheave immobilized in rotation on the connecting rod. The removable cam flange (8) and all of the parts which are assembled therein, pivot around the pin (5.2) formed on one of the sides of the median sheave. When the support flange (1) - not shown - is in place, the connecting rod is movable in rotation, but trapped in translation. The cam (6) is assembled on the flange (8) by means of the screws (9). The lever control lever (12) is articulated on the pin (17) formed by the cylindrical head of a screw which encloses the cam flange and a socket pierced with a threaded hole. The lever spring takes place around this socket which has a pin around which the counter-lever is articulated. A cylindrical nut (aesthetic and difficult to dismantle without appropriate tools) immobilizes the lever control lever (12) the spring (18) - hidden - and the counter-lever (14) - also hidden - with the appropriate clearances to allow free joystick rotation.

The cam flange (8) articulated on the pin (5.2) present on one side of the median sheave, behaves like the beam of a balance whose arms are uneven. The attachment of the load P in the hole (6.3) of the cam acts on the beam with the short lever arm Lp. The reaction P takes precedence over the load P acts on the beam with the long lever arm Lb at the end of which the lever control lever (12) is articulated on the cylindrical head of the screw (17). The built scale reduces the weight P to P prime according to the relationship:

p, Lp * _P

lb

This constitutes a first reduction. It can be seen that P prime is directed upwards. To counterbalance P prime and lessen the pinching of the cam on the rope to begin to descend, it is necessary to gradually subtract from it a force directed downwards.

The lever control handle (12) has a protrusion (12.1) which comes to rest under an appendage (10.2) of the connecting rod when the handle is actuated. This device acts as a lever. The resistant lever Ld represents the length, projected along the horizontal, separating the axis of rotation (17) of the lever control lever from the contact of its protrusion (12.1) with the appendage (10.2) of the connecting rod. This lever counterbalances the effort P prime directed from the bottom up. The engine lever Lm is actuated by manual force M which the user applies to the lever to descend. Note that the engine lever arm Lm according to its projection on the horizontal, can be extended to Lm prime because the working hand can operate in the direction which suits it best; this concomitant increase in the lever arm acts in the direction of less effort. To counterbalance P prime and start to descend, the user will have to weigh on the joystick, assumed to be gripped at its end, with a force M according to the relationship:

P * L d

MLm

It does not seem unnecessary to recall here that the weight P suspended on the cam in (6.3) and its counterpart P prime will be lightened by the force corresponding to the weighing carried out by the user on the lever. This leads to the need to balance the moments on either side of the rope before starting to decrease P prime. This rebalancing of the moments results in a slight oscillation of the descender resting on the loaded rope against the high sheave. It is only when this equilibrium of moments is reached that one begins to counterbalance P prime. This aside only tends to explain why the descender begins to oscillate when you press the joystick (which will be noticed by any attentive user) before you can start to descend. Due to the activated total reduction, the weighing force M applied to the joystick remains very low compared to P and is not worth going into unnecessary calculations since it is only a question of describing a functional embodiment ...

On the other hand, to quantify the reduction actually obtained, it suffices to measure the force applied to the end of the lever, according to the vertical, with a dynamometer. With a rope eight millimeters in diameter and one hundred kilograms of suspended load, the self-locking mechanism disappears for a manual weighing of less than three decanewtons. The descent begins at a speed of a few centimeters per second.

To increase the speed of descent, it is necessary to weigh more on the lever (12) to decrease the gripping force acting on the rope. The increase in the angle of rotation of the handle (12) causes the resistant lever Ld to increase by sliding the projection (12.1) against the appendage (10.2). The increase in length of the lever Ld causes the increase in M if it is admitted that Lm or better Lm prime vary correlatively little. Fine calculations would make it possible to quantify these modest fluctuations ... When the space separating the cam and the low sheave approaches the nominal diameter of the rope, the retention force applied to the free strand tends towards zero (neglecting the weight of the pendant length). Braking is limited to the sole contact of the running string against the low, middle and high sheaves. The descent speed can then reach several meters per second.

The desired descent speed is obtained by an appropriately dosed weighing, applied to the joystick with one hand, without any contact with the running rope. The user has one free hand. This innovative arrangement corrects the problems posed: (a) hand burns and (f) two hands essential for descending with a self-locking descender.

Finally, note that the loaded rope, flattened by the pinching of the cam against the low sheave, then scrolls between the V-shaped groove (vee) of the high sheave which gives it its circularity. This arrangement satisfies the required quality (k) re-establishment of the circularity of the rope, already present on other descenders.

Referring to Figure 5, we show how the open descender is placed on the hanging rope. When the ball pin (35) which ensures the closing of the descender by simultaneously inserting it in the median hole of the flanges (1.1) and the central hole of the medial sheave (5.3) is removed, the descender can open. The pin is made captive by a flexible link attached to the descender by means of the flange assembly bolt on the low sheave (36). The carabiner (38) hooked into the hole of the cam (6) constitutes a fixed point since it is hooked to the user's harness. By grabbing the descender with its support flanges in full hand and pulling slightly obliquely, the connecting rod (8) and all the elements attached to it, pivot around the pin (4.1) formed on the low sheave. The cumulative width of all these members does not exceed the space available between the support flanges between which they can be inserted freely. The lever support cam flange (8) and the cam flange (7) assembled on the cam by the screws (9) pivot around the pins (5.2) formed on either side of the median sheave. The torsion spring support stops causing the lever to fold, one (33) - hidden, but in dotted lines - fixed on the cam flange (8) and the other (20) - also hidden, but in dotted lines - come into contact with each other, the cam flange (8) and the lever (14) are no longer articulated. The lever considered in its entirety (12), (13) and (14) abuts against the high sheave. This abutment coincides with the full opening of the descender, allowing the introduction of the larger diameter cord provided (40) between the flange (1) and the cam flange (7) which covers the median sheave. It is the descender which is placed on the rope and not the opposite. The absence of complex sinuosities limits the errors of installation, without canceling them! This particular point will be described later ...

To close the descender, simply release the manual traction exerted by the hand pulling on the support flanges. Under the action of the lever spring, the descender begins to close. So that the median sheave can insert the cord between the top and bottom sheaves, the mobile equipment must be pushed back between the flanges. This operation is facilitated by pressing with a finger on the end (10) of the connecting rod which acts as a lever. When the connecting rod comes into contact with the top sheave, the rope is in place, the through holes (1.1) and (5.3) of the pin are perfectly aligned. The locking pin (35) can be inserted. If during the contact of the connecting rod and the top sheave of dirt (clay) had been introduced between these two parts, the thinned edge (10.1) will facilitate their evacuation.

The descender is always attached to the user's harness during the rope entry or removal operations. This provision meets the required quality (1) a descender must be captive, already present on other devices.

Referring to Figure 6, we see that the descender is placed upside down on the rope. This upside down is the only possible introduction error for the descender on the rope. The flange initially identified (2) the cam flange (7) and the assembly elements do not appear on the drawing which is limited to showing the parts involved in the functional description.

The low sheave (4) and the high sheave (3) are screwed onto the flange (1). Due to the upside down, their respective positions are reversed. The cord (40) is inserted between the sheaves (4) and (3) by the thrust of the median sheave (5). The locking pin, which does not appear in the drawing, is assumed to be in place in the hole (5.3). The attachment of the load, applied in the hole (6.3) of the cam (6) causes the rope to be pinched between the boss (6.1) and the sheave (3). The boss (6.1) of the cam is profiled to be inserted in the V-shaped groove (vé) of the sheave (3) so as to come and pinch the rope of smaller usable diameter. The gripping force of the Fa string results from the same set of levers as those which lead to the self-locking already described. The load P is immobilized on the descender mounted upside down. The handle (14) is folded against the sheave (3) by the action of the spring (18) bearing on the screws (33) and (20). Thus placed upside down, no action on the joystick is possible to start a descent. The distracted user has only one solution: put his descender the right way!

This innovative arrangement corrects the problem posed (h) incorrect insertion of the rope into the device.

Referring to Figures 7 and 8, we discover how the automatic folding of the joystick can be voluntarily suppressed when the descender must be controlled remotely by an auxiliary cord, constrained to act vertically, which is no longer possible when it is folded up.

The descender is shown on the rope (40) in a self-locking situation. The load is suspended from the carabiner (38). The descender is shown closed by a pin (22) whose operation will be described later. The control handle (12) of which only the lever (12.1) is visible, the spacer (not visible) and the counter-handle (14) are drilled at their end with a hole (14.1) allowing the passage of a carabiner (39) in which a cord (41) can be hooked enabling the joystick to be operated remotely. The latch (19) is articulated in rotation on the axle bolt (20) assembled on the counter-lever (14). A boss (19.1) formed near the articulation hole (20) of the latch rests on one end of the torsion spring (18) which causes the automatic folding of the lever when it is released. The latch is housed in the space separating the lever control lever (12) and the counter-lever (14). In the rest position (dotted line) the latch is inserted in a notch in the counter-lever. To activate the latch, keep the handle unfolded. The self-locking remains maintained, because the projection (12.1) of the lever control lever remains out of contact with the appendage (10.2) of the connecting rod; the action on the lever allows only to be able to activate the latch (19) by pressing on the head of the bolt (21) with a finger. In this rotational movement intended to make the latch active, the boss (19.1) compresses the spring (18) to neutral. As soon as the neutral point is crossed, the spring completes the rotation. Partial view along A: the bolt (21) immobilized on the latch (19) is profiled at its end by the pal3066396 fear (21.1) which comes into contact with the curvature formed on the cam flange (8). During the descent, the rotation of the lever control lever (12.1) articulated at (17) comes into contact with the appendage (10.2) of the connecting rod (8). During the descent, carried out at variable speed if necessary, the sliding movement of the probe (21.1) maintained in abutment on the curvature of the cam flange (8) by the spring (18) follows the rotation of the lever. When the user releases the joystick: self-locking works; the descent stops; the lever tends to fold back under the action of the spring (18); the probe (21.1) continues its travel on the curvature of the cam (8) and engages in the notch (8.1) connected to this curvature. The lever retraction movement is stopped. The action exerted at a distance by means of the cord (41) can be carried out vertically. This device makes it possible to control the descent with a foot or a thigh actuating a cord or a strap suitable for this use. It allows a caver engaged in a narrowness to remotely control the descender at the end of the lanyard while benefiting from the variable descent speed and, above all, self-locking.

This innovative arrangement corrects the problem posed (g) no self-locking available in narrow passages. In addition, it opens the possibility of operating the descender from a distance, possibly with a foot, which then leaves both hands free.

With reference to FIG. 9, the descender folded back in the transport position is observed. When it is not used to descend, the descender is less troublesome when it is carried on the user's belt or on a cord ring worn over the shoulder. The device should therefore have a reduced bulk.

Under the action of the spring (18) taking support points on the assembly members (33) and (20) the lever considered in its entirety (12,13,14) articulated in (17) folds against the sheave top (3) - dotted. In reaction to this support, the lever (14) forces the cam flange (8) in rotation until it comes into abutment against the bottom sheave (4) - in dotted lines. When the locking pin (22) is in place, the descender is folded back to its smallest volume and can be transported by the carabiner (38) inserted in the hole of the cam (6).

Referring to Figure 10, we discover a new feature offered by the descender object of the invention. This device allows a climber progressing in climbing to be secured by the second roped stationed below. For clarity, the previously marked support flange (2) and the previously marked cam flange (7) and the assembly bolts do not appear in the drawing. The rope (40) is inserted into the descender. The strand on which the climber is tied, or tether strand, comes out in contact with high sheave (3). The free end comes out of the descender between the cam (6) and the low sheave (4); it must be inserted in the hanger of the carabiner (38), hooked to the harness of the second roped party. The free sliding of the rope, of which the two strands are held manually, is made possible by the space preserved between cam and low sheave. To preserve this space, a belay latch (29) is movable in rotation by means of a device internal to the lever which will be described later. The latch (29) is fixed to this internal device by the screw (30.2) and the pin (30.3). When the latch (29) is manually activated in rotation, it comes into abutment against the gou3066396 pile (34) inserted in the counter-lever (14) and the spacer (hidden). The latch (29) immobilized between the pin (34) and the high sheave (3) perpetuates the space appearing between the cam (6) and the low sheave (4) when the rope of larger usable diameter is inserted in the descender . Maintaining the belay latch under the high sheave is ensured by the spring (18) bearing on the screws (33) and (20) which folds the lever against the sheave. This mechanism determines a threshold below which self-locking is inhibited; the rope slides freely between cam and sheaves.

Referring to Figure 11, we are witnessing the operation of the belay device when the climber falls. For clarity, the previously marked support flange (2) and the previously marked cam flange (7) and the assembly bolts do not appear in the drawing.

When the second of the rope sees the climber fall, he just has to hold the free strand of the rope still with his hand. A little effort is enough. Under the action of the restraint applied to the free strand, the rope stretched by the fall of the climber pulls up the descender hooked to the harness of the second by the carabiner (38). Under this stress, the cam (6) and the cam flange (8) pivot around the pins (5.2) formed on either side of the median sheave (5). This rotation forces the belay pallet (29) to bypass the high sheave (3) despite the action of the lever spring (18) which opposes this movement. The self-locking inhibition threshold is exceeded. Autoblocking is reactivated. The fall of the climber is intercepted.

Referring to Figures 12, 13 and 14, we discover the mechanism related to the operation of the belay latch incorporated in the handle, apprehended in its entirety. For clarity, the counter-lever previously identified (14) and the articulation mechanism with spring, allowing the lever to fold, do not appear in the drawing.

Fig. 12: Belay activated. The spacer (13) separates the lever control lever (12) and the counter-lever (not shown). This spacer is the comfort thickness required to handle the joystick. The spacer is pierced with a cylindrical hole (13.1) for receiving a hexagonal section shaft (30). The two sides of this shaft are turned into cylindrical sections for the use of trunnions, articulated in holes drilled opposite in the lever control lever (12) and the counter-lever. The spacer comprises a light (13.2) blind at one of its ends, but which leads to the hole in which the shaft of hexagonal section (30) can freely rotate. A spring (31) working under compression is inserted into the slot (13.2). One of its ends takes support at the bottom of the blind light. The other end of the spring is provided with a metal piece (32), for example a rivet with a flat head, inserted by friction between the terminal turns of the spring. This part provides an interface function between the spring and the sides of the hexagonal shaft when the latter is rotated. The belay latch (29) is fixed on a trunnion (30.1) turned on the hexagonal shaft (30). The diameter of this pin makes it possible to receive, in the same section, the fixing screw (30.2) of the latch assembled on the shaft and a pin (30.3) preventing the relative rotation of the latch and the shaft. The spring (31) is inserted into the hole (13.2) with an initial compression sufficient to immobilize the rotation of the hexagonal shaft when it presses against one of the sides. In this position, the belay latch abuts under the high sheave (3). The pin (34) gives the latch (29) immobilization in redundant rotation of that caused by the thrust of the spring against one side of the hexagonal shaft. This redundancy is not superfluous; it freezes the position of the latch in abutment when it must remain in contact with the high sheave (3) whatever the stresses transmitted to it by the lever.

Fig. 13: Manual rotation. A manual action directly exerted on the locking latch (29) causes it to rotate, either from the position where the belay is activated towards the rest position, or from the rest position towards the activation of the belay. Every 30 °, the angle which separates two adjacent sides of the hexagon (30) compresses the spring (31) which rubs against the interface part (32). The belay latch finds a stable position every 60 °.

Fig. 14: Latch at rest. A total rotation of 300 ° brings the latch to the rest position. One of its sides then comes into abutment against the pin (34). This deliberately large angle of rotation prevents the latch from being activated inadvertently and allows it to retract into the template of the lever. The holes (15) allow the lever control lever, the spacer and the counter lever to be assembled with screws or rivets.

These additional provisions validate the functional possibility mentioned in (m) satisfying the constraints relating to the belaying of a climber from below.

Referring to Figures 15, 16 and 17, we explain the operation of the guided captive pin drawn in the open position. Figure 15 shows the descender seen from the side; Figure 16 details the manufacture of the pin seen according to A; Figure 17 is a right view of Figure 15 (without the cam). These three figures are linked in the following description.

A side view shows the arrangement of the components of the descender, without the handle. The support flanges (1) and (2) are bolted to the top (3) and bottom (4) sheaves. Note the connecting rod (10) articulated around a pin (4.1) formed on the low sheave. The connecting rod supports the movable assembly consisting of the cam flange supporting the lever (8) of the cam (6) and the cam flange (7). The connecting rod and the moving part are inserted between the support flanges with the clearance which is suitable for their free rotations.

The support flange (2) receives the protruding pin guide (23) assembled on the flange by screws (27). This guide has a hole aligned with those of the flanges and the moving part. The drilling diameter of all the holes concerned by the closure of the descender allows the pin (22) to slide there freely; the insertion of the pin in the various holes is facilitated by the chamfer turned at its end. A second bore, perpendicular to the first, is formed in the guide (23). It delivers passage to a rod (24) which will act as a lock. A sheet bent at right angles, also drilled to allow the passage of the pin, is attached to the guide. The screws (27) assemble the assembly by means of attractive circular nuts which are difficult to dismantle without appropriate tools. Note that these screws can be replaced by rivets. The square folded part of the sheet (26) is pierced with a hole for guiding the rod of the red ver3066396, aligned with that of the pin guide. The lock rod is provided with a collar (24.2) on which a compression spring (25) takes a first bearing point. The second spring support point is provided by the sheet (26) bent at right angles. The accessible end of the lock rod is equipped with a gripping pallet allowing the rod to be maneuvered. The pin is provided with a mortise (22.1) hollowed out according to a generator. The width of the mortise allows the bolt rod to enter it. The two ends of the mortise act as limit switches by stopping the movement of the pin (22) when they come into contact with the bolt rod. This mortise and the bolt rod which slides there make the pin captive. At the bottom of the mortise is pierced a through hole (22.3) of a sufficient diameter so that the bolt rod can be inserted when the pin is closed. When the pallet (24.1) is lifted manually, it abuts against the head of the screw (37). In this position, the other end of the bolt rod arrives just at the bottom of the mortise (22.1); a slight play allows the free sliding of the guided pin (22). The flange assembly screw (37) at the top sheave has a circular head so that the distance between the head of this screw and the bottom of the mortise is independent of the angle of rotation necessary for tightening the screw. The full opening of the pin is obtained by pulling on the grip rod.

(22.3). The rod (24) of the bolt in abutment against the mortise acts as limit switch. Under the action of the compressed spring (25) the bolt rod presses at the bottom of the mortise (22.1). This slight pressure is enough to immobilize the pin in translation while its end is flush with the inside of the flange (2). It is then possible to open the descender, because the entire moving assembly assembled on the connecting rod is free to rotate.

With reference to FIGS. 18 and 19, the operation of the guided captive pin drawn in the closed position is explained. Figure 18 shows the descender seen from the side; Figure 19 is a right view of Figure 18. These two figures are linked in the following description.

When the guided pin (22) is pushed back manually through the holes of the mobile assembly (6), (7), (8) and (10) and those of the support flanges (1) and (2) the descender will to close. During this translational movement, the lock rod rubs against the bottom of the mortise. At the bottom of the stroke, the bolt rod (24) actuated by the compressed spring (25) simultaneously plunges into the hole (22.2) drilled at the bottom of the mortise, outside the zone constrained by shearing, and into the through hole ( 23.1) drilled through the guide (23). The pin is locked in the closed position. The through hole (23.1) is used to eject dirt that could have settled on the bottom of the mortise when the pin is open. The visual mark (28) released by the correct engagement of the lock, attests to the proper functioning of the descender closure and the effective locking of the guided pin.

This innovative arrangement corrects the problem posed (i) descent on a poorly closed device.

With reference to FIGS. 20 and 21, it is noted that two mounting possibilities are offered for actuating the lever of the descender. The guided captive pin and all the elements associated with it: guide, lock, spring, folded sheet and bolts are assembled on the identified support flange (2) with which they form a functional unit independent of the rest of the device.

The two support flanges (1) and (2) have an identical cutout and holes. They can therefore be swapped to obtain different assemblies.

According to FIG. 20, there is an assembly making it possible to operate the descender with the right hand.

According to Figure 21, there is an assembly for operating the descender with the left hand.

This possible swapping of the flanges makes it possible to always keep the operating and safety members facing the user: control of the lock (24.1) pin gripping rod (22.3) and above all the visual reference (28) attesting to the correct closing of the descender.

Summary: all the problems posed, summarized from a) to i) are resolved by the innovative devices described. All the required qualities, listed j) k) and 1) already existing on other devices, are also present. Finally, the additional functionality announced (m) allowing the belaying of a climber from the bottom, is available on the descender object of the invention.

By way of nonlimiting example, the prototype descender manufactured according to the described arrangements fits into a rectangle of 125 millimeters in length and 100 millimeters in width, when it is folded into the transport position. The overall thickness, measured on the guided locking pin, is 60 millimeters. It works with ropes from 8 to 11.5 millimeters in diameter made of synthetic materials (Nylon, Tergal, Kevlar) whatever their surface condition, water imbibition or core gel.

The descender according to the invention is intended for fans of verticality concerned with safety and comfort. Being able to have one hand free at all times, and occasionally both hands, while varying the descent speed conveniently, offers new possibilities for use, either during a leisure occupation or in the context of a professional activity. .

Claims (12)

1) Descender used for the descent of a person along a moored rope (40), characterized in that it comprises two support flanges (1) and (2) fixed on either side of two sheaves ( 3) and (4) immobilized in rotation, which sheaves, by their width, release a space between the two flanges making it possible to receive a median sheave (5) immobilized in rotation and in translation by screwing (11) on a connecting rod (10) articulated on a journal (4.1) or a ring (4.3) present on one side of the sheave (4), the space available between the support flanges makes it possible to receive the rope (40) inserted in contact with the sheaves (3), (4 ) and median (5) to constitute reduced braking surfaces, the running of the rope is controlled by the cam (6) assembled between the cam flange (7) and the joystick support cam flange (8) articulated on pins (5.2) located on either side of the median sheave, with the same center as the hole (5.3) used to immobilize the bi it in rotation with a ball pin (35), the user hooks into the hole (6.3) of the cam arranged in levers, the motor lever is actuated by the weight of the user, the resistant lever, shorter as the engine lever, apply a force greater than the weight of the user to the plucked rope against the sheave (4) so as to obtain self-locking. 2) Descender according to claim 1, characterized in that the circular sheave (4) immobilized in rotation, of radius r can be replaced by a shoe (4.1) immobilized in rotation, having a curvature of radius R> r symmetrical to the radius of curvature of the cam (6) to preserve the pinched cord (40) from a punctual compressive necking. 3) Descender according to claim 1, characterized in that the cam (6) and the cam flange (7) assembled by screwing (9) can constitute a single piece. 4) Descender according to claims 1 to 3, characterized in that the cam flange for the joystick support (8) behaves like the beam of a balance with unequal arms articulated on a journal (5.2) of the median sheave, the arm of engine lever is actuated by the weight applied in the hole (6.3) of the cam (6), the resistant lever arm, longer than the engine lever arm, transfers a reduced part of this weight to the screw (17) where is articulated the control handle of the descent apprehended in its entirety (12,13,14), which constitutes a first reduction device. 5) Descender according to claims 1 to 4, characterized in that the control lever for the descent apprehended in its entirety (12,13,14) articulated in (17) on the cam flange (8) is arranged in reduction levers where the resistant lever has for length the distance separating the axis (17) of the lever control handle (12) from the projection (12.1) taking sliding bearing point under an appendage (10.2) of the connecting rod (10 ), the control lever (12,13,14) acting as a motor lever, longer than the resistant lever, constitutes a second reduction device actuated by a manual weighing applied from top to bottom, which has the effect of reducing the force pinch applied by the cam (6) on the rope (40) wedged against the sheave (4), which rope begins to slide, to increase the speed of descent it is necessary to increase the weight on the joystick (12,13,14) , because the resistant lever of the lever control lever (12), articulated s ur the axis (17) sees its length increase as the projection (12.2) moves by sliding under the appendix (10.2) for use as a fixed point supported by the connecting rod (10). 6) Descender according to claims 1 to 5, characterized in that the movable assembly assembled on the connecting rod (10), that is to say the cam (6) the cam flanges (7) and (8) thus that the control handle apprehended in its entirety (12,13,14) passes freely between the support flanges (1) and (2) when the ball pin (35) is withdrawn from the closing hole (5.3) drilled in the flanges supports (1) and (2) the central sheave (5) and the cam flanges (7) and (8), a manual traction applied to the end of the support flanges assembled by a bolt (36) reacts with the fixed point consisting of the carabiner hooked to the user's harness (38) which allows the connecting rod (8) to pivot on the pin (4.1) formed on one side of the sheave (4), the space cleared between the support flange (1 ) and median sheave (5) is adjusted by the contact of the lever (12,13,14) sliding by pivoting in contact with the sheave (3) as soon as the rotation around its axis (17) is stopped being brought into contact with the screws (20) and (33) also serving as a fulcrum for the lever spring (18), the descender is placed on the hanging rope (40) of larger diameter provided without having to touch the rope, the descender is closed by manually acting on the end of the connecting rod (10) which activates a motor lever arm taking support at (4.1) to force the median sheave (5) acting as an arm resistant lever, shorter than the engine lever, to introduce the rope between the sheaves (3) and (4) with a force greater than that applied in (10), the connecting rod abuts against the sheave (3) acting as an end stroke, eliminating any dirt deposited with its thinned edge (10.1) so that all the holes (5.3) for inserting the locking pin (35) are perfectly aligned before introduction of the latter. 7) Descender according to claims 1 to 6, placed by mistake upside down on the rope (40), characterized in that the cam (6) on which the user hangs in the hole (6.3) is arranged in levers, the engine lever is actuated by the weight of the user, the resistant lever shorter than the engine lever, applies to the rope pinched in the V-groove (vé) of the sheave (4) by the boss (6.1) of the cam a force greater than the weight of the user so as to obtain self-locking, the handle apprehended in its entirety (12,13,14) folded by the spring (18) bearing on the screws acting as stops (20) and (33) does not work in this inverted position. 8) Descender according to claims 1 to 6, characterized in that the handle, apprehended in its entirety (12,13,14), is pierced at the end opposite to its axis of articulation (17) with a hole ( 14.1) passing through the lever control lever (12) the spacer (13) and the counter-lever (14) allowing a snap hook (39) fitted with an auxiliary device (41) allowing action 3066396 ner remote controller, the device (41) constrained to operate according to a line of action close to the vertical imposes to paralyze the automatic folding of the controller subjected to the action of the spring (18), a latch (19) is assembled on the counter-lever (14) by means of the axis (20), the latch has a boss (19.1) cooperating with the spring (18) to define two stable states separated by a neutral point, at rest the latch (19 ) immobilized in a first stable state retracts and stabilizes in a notch in the counter-lever (14), the latch activates by manually actuating the protuberance (21), as soon as the neutral point is exceeded the spring (18) completes the rotation maneuver, the latch stabilizes in the second stable state and applies the feeler (21.1) in contact with the angular sector, same center as the axis (17) cut on the edge of the cam flange (8) against which it moves when the lever is actuated, when the lever is released the feeler (21.1) engages in the notch (8.1 ) connected to the angular sector of the cam flange (8) where it remains in abutment, which keeps the lever unfolded. 9) Descender according to claims 1 to 6, where one uses the automatic folding of the lever actuated by the return spring (18) to create an additional function, allowing the belaying of a climber by an auxiliary aid located in below, characterized in that the spring (18) cooperates with the lever supporting the belay latch (29) movable in rotation when it is actuated manually until it locks against the pin (34) which paralyzes the rotation of the whole of the mobile assembly, cam (6) cam flanges (7) and (8) around the pins (5.2) formed on either side of the median sheave (5) the belay latch (29) by its support maintained by the spring (18) under the sheave (3) creates a threshold below which the self-locking is paralyzed, which perpetuates a space for free sliding of the rope of larger expected diameter (40) flowing between the cam (6) and the sheave (4) when its movement is controlled manually ment during the belaying of the climber, if the climber falls the manual restraint of the free end of the rope (40) forces the belay latch (29) to bypass the sheave (3) by pushing the still actuated lever into the folded position by the spring (18), the previously preserved free sliding space is eliminated, the cam (6) clamps the rope (40) against the sheave (4) the self-locking restored immobilizes the climber in suspension on the rope. 10) Descender according to claim 9, characterized in that the operating mechanism of the belay latch (29) and consisting of a shaft (30) of hexagonal section, provided laterally with two pins (30.1) for use as axes of rotation, turning in holes made on the lever control lever (12) and the counter-lever (14), the rotor thus formed is housed in the spacer (13) pierced right through with a circular hole (13.1) centered on the holes drilled in the handles, a light (13.2) blind at one end opens into the circular hole (13.1), a spring (31) working in compression is inserted in the light (13.2) at the bottom of which one of its ends takes support, in the first turns of the other end of the spring is inserted an interface piece (32) ensuring a sliding contact of the spring mounted with an initial compression against one of the sides of the tree (30), tree (30) e t the spring (31) inserted in the spacer (13) is immobilized and protected from dirt when the lever control lever (12) and the lever counter (66) are assembled on either side of the spacer with the screws (15), the belay latch (29) is assembled on the pin articulated in the counter-lever (14) so as to come into contact with the sheave (3) when the space necessary for the sliding of the rope larger planned diameter (40) between cam (6) and sheave (4) is released, this assembly consisting of an eccentric screw (30.2) cooperating with a pin (30.3) eliminates any risk of relative rotational movement of the latch belay (29) and of the support shaft (30) immobilized by the spring pressing against one of the sides of the hexagon, the pin inserted in the counter-lever (14) and the spacer (13) cooperates so redundant with the action of the spring (31) by perpetuating the position of the pallet (29) under the re a (3), the belay pallet is put to rest manually, after 300 ° of rotation the belay pallet is in the rest position, immobilized by the spring (31) and the pin (34) making end of race office against which it comes into abutment. 11) Descender, the closing device of which, effected by means of a ball pin (35) inserted into the orifice (5.3) immobilizing the entire mobile assembly supported by the connecting rod (10) can be replaced by a more efficient device, characterized in that the pin (22) has a shallow mortise (22.1) cut according to a generator, having a through hole (22.2) and a manual gripping rod (22.3) fixed to one of its ends, a guide (23) pierced with a hole for the passage of the pin (22) is assembled beyond the support flange (2), a cylindrical rod for use as a lock (24) slides in a hole (23.1) in the guide (23 ) perpendicular to that of the pin, a sheet bent at the square (26) pierced in its fold with a guide hole of the bolt, attached by the assembly means (27) to the guide (23) and the flange (2) allows the compression spring (25) to take a first support point under the r fold of this sheet and a second point of support on a collar (24.2) formed on the bolt rod (24), the bolt rod (24) is provided with a manual gripping pallet (24.1) fixed at its end , when the pin (22) is withdrawn, its beveled end is flush with the edge of the support flange (2) allowing the opening, the bolt rod inserted at the bottom of the mortise acts as limit switch when it abuts against one end of the mortise and makes the guided pin (22) captive, the gripping palette (24.1) rubs against the flange (2) which prevents any parasitic rotation, then comes into abutment under the round head assembly bolt (37) of the flanges , the pressure of the spring on the lock rubbing at the bottom of the mortise, with a clearance defined by the pallet (24.1) in abutment under the bolt (37) immobilizes the pin in the withdrawn position, when the pin (22) slides close in the holes (5.3) drilled in the support flanges (1 and 2) ai nsi only in the holes of the moving element (6,7,8) articulated on the connecting rod (10), when the bolt (24) comes opposite the hole (22.2) perforating the bottom of the mortise the spring (25) push the lock into the hole, any dirt is removed through the hole (23.1) drilled in the guide (23), the guided captive pin is locked in the closed position. 12) Descender according to claim 11, characterized in that the whole of the operating mechanism of the guided captive pin (22) assembled on the support flange (2) by the assembly means (27) constitutes an assembly for permuting the support flanges (1) and (2), during the assembly of the descender, because the holes provided therein and their cutouts are identical, the control handle apprehended in its entirety (12,13,14) can thus be operated either with the right hand or with the left hand, the lock control pallet (24.1) (24), the gripping rod (22.3) of the pin (22) and the visual mark (28) attesting to the locking 5 staff will always be placed in front of the user.