Technical Field

The present invention relates generally to sport climbing safety devices, and more particularly to an apparatus for automatically belaying a climbing person.

Background Art

Climbing of rock faces, boulders, and artificial walls has become increasingly popular as a recreational and competitive sport. In this exciting and challenging activity, climbers often fall so that they have taken to protecting themselves from severe ground impact and consequent injury by attaching themselves to a rope. The tension, feed-out, and braking of the rope is controlled by another person in a process referred to as 'belaying' .

In a common procedure known as 'top-roping' a rope is lowered from the top of a wall or rock face and the climber ties himself to one end of this rope either directly around the waist, or more commonly, by means of a harness having a waist band and leg loops. The belayer may be positioned either at the top of the wall or the bottom. For the latter case, the rope is made to pass through a metal ring attached to a fixture at the top of the wall so that both ends are on the ground. The climber 'ties in' to one end and the belayer ties himself to the other.

When the climber begins to climb, the belayer pulls in the rope so that it remains taut or perhaps slightly slack between himself and the climber. If the climber falls, the belayer holds the rope firmly, thus arresting the fall so that the climber is hopefully not injured. In order to most easily catch the climber's fall, the belayer applies friction to the rope, either by holding it against his waist in what is known as a 'body belay', or by pinching it using a belay device such as a 'sticht belay plate', or a 'figure eight' device and a gated metal ring known as a 'carabiner' .

Such belay devices have been invented to assist the belayer in gripping the rope more easily with only limited slippage. While these and certain other belay devices, allow the belayer to hold the rope more easily, they must still be manually operated. Specifically, the rope must be fed out through the belay device to the ascending climber,* and the rope must be manually pulled into a locking position within the device in order to stop the rope from playing out and thereby arrest the climber's fall.

Frequently, during an ascent, climbers may become fatigued, and wish to rest. Some climbers will call to their belayer to provide tension on the rope so that they may rest by allowing the rope to support some or all of their weight. This can be as much an annoyance to the belayer as it is relief to the climber since the tension force is often transmitted to the body of the belayer if his body is used as a counter weight as is the common practice.

Sometimes if a climber is having difficulty with a particular move or set of moves on the route the belayer will provide continuous tension by pulling the rope in with substantial force, thus assisting the climber with his ascent. This practice is more common with novice climbers who have not yet developed sufficient strength or skill to climb routes unassisted. However, even expert climbers will often engage in an activity called 'hang dogging', in which they rest on the rope and repeatedly rehearse difficult moves and sections of a route before attempting to link all the moves together in one continuous ascent.

Once the climber reaches the top of the wall, (or falls before reaching the top) it is a common procedure for the belayer to lower the climber by relaxing his hold on the rope, or gradually releasing his belay device. The belayer then slowly feeds rope out through the belay device so that the climber returns to the ground in a controlled manner without injury.

Unfortunately, the process of belaying is often tiresome and dull, so that belayers occasionally become distracted or bored and fail to belay properly. This may result in grave injury to the climber. For example, an inattentive belayer may allow excess slack to accumulate in the rope between himself and the climber so that if the climber falls the fall may be long enough for the climber to attain sufficient speed to hurt himself on a ledge or rock projection. In other cases the belayer may fail to lock the rope properly in a belay device, or may let go of the rope entirely allowing the climber to fall all the way to the ground. Some belayers may simply lack the competence to use the belay devices properly due to improper training; others are simply irresponsible - not understanding the importance of proper belay until it is too late. Human error on the part of the belayer is responsible for a substantial percentage of the injuries which occur while top-roping. Seldom is injury due to equipment failure.

Belaying is an unpleasant chore due not only to its often prolonged tedium, but also to the shocks incurred by the belayer's body when a climber falls. Furthermore, the lowering process can also be difficult using currently available devices particularly with heavier climbers. Belayers have been injured by rope burns and burns from the belaying devices which tend to become heated by friction with the rope. Finally, hair and clothing also can become entangled with the rope and present belaying devices resulting in further injuries to both climbers and belayers.

Some climbers prefer to climb alone, without the company or assistance of a belayer. Sometimes these climbers will climb solo, without the use of a rope. This practice is, needless to say, dangerous, both to the climbers themselves, and to individuals who may be standing or sitting beneath them.

While most belaying devices of prior art require a belayer to operate, there are some devices, designed to lock automatically without a belayer' s assistance, which may be used for 'self-belay' . However, these devices are sometimes unreliable and difficult to use. With these devices, a rope is affixed by the soloist to the top of the wall and to the bottom as well. The soloist then begins climbing from the bottom of the wall with the self belaying device attached to his harness and sliding upward on the rope. The device is designed such that it may slide upward on the rope with little friction, but grabs hold of the rope when it is forced downward. If the climber falls, the device clutches the rope and thereby prevents the climber from hitting the ground and injuring himself. These devices require that their grip on the rope be manually released for the climber to commence lowering. Thus, if a climber falls, bangs his head, and becomes unconscious, he would be suspended high above the ground at the point where self belay device stopped his fall. If the climber were to need immediate medical treatment, it could prove difficult for medical rescue personnel to reach him in time.

Thus, it is an object of the present invention to provide an apparatus for automatically belaying a climber without human assistance.

It is a further object to provide an apparatus which reduces the chance for human error while belaying thereby preventing unnecessary injury.

It is a further object to provide an apparatus for automatically slowly lowering a person to the ground.

It is a further object to provide an apparatus for arresting the fall of a person, and suspending him near the point where he fell.

It is a further object to provide an apparatus for assisting a climber's ascent by applying an upward force to the climber.

It is a further object to provide an apparatus which allows climbers to practice climbing alone.

Disclosure of the Invention This invention provides an apparatus for automatically belaying a climbing person. The apparatus consists of a specialized reel which feeds out slack and takes up rope when the climber is moving slowly and under his own control. If the climber falls, and begins to pull rope out rapidly, a drag producing device limits his downward descent to a comfortable speed which is unlikely to produce injury. The apparatus may be equipped with a fail-safe braking mechanism so that the user may rest and repeatedly attempt to climb from near the point at which he fell. This braking mechanism may be released manually by the climber by pulling a brake release cord. The apparatus may also be equipped with a mechanism for providing upward tension to assist the climber in his ascent.

Brief Description of the Drawings

For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description and the accompanying drawings, in which:

Figures la, lb, lc, and Id are a series of schematic diagrams illustrative of the function of the invention.

Figure 2 is a schematic diagram depicting an apparatus illustrative of the invention.

Figure 3 is a schematic diagram depicting an alternative apparatus illustrative of the invention.

Figures 4a and 4b are schematic diagrams depicting an alternative apparatus illustrative of the invention.

Best Mode for Carrying Out the Invention Figures la-d show schematically the general principles of operation of the of the present invention.

Figure la shows a climber 1 is engaged in recreational ascent of a cliff or wall 2 by stepping on and pulling on

holds 3. For safety, and for descending purposes, the climber 1 wears a harness 4 which is attached to a rope leader 5. This rope leader 5 is, in turn, attached to a lighter and thinner cord 6 by means of a metal ring called a carabiner 7. The cord 6 is, in turn, attached to a reeling device 8. The reel 8 applies a light tension as indicated by the upward pointing arrow 9 sufficient to keep the cord 6 and rope 5 taut or perhaps only slightly slack, but not so strong as to assist the climber 1 in ascending the wall 2. As the climber 1 ascends, the reeling device 8 reels in the slack of the cord 6.

As shown in figure lb, when the climber 11 falls or voluntarily lets go of the holds 12, the reeling device 13 increases its tension on the cord 14 as indicated by the heavy arrow 15, thereby reducing the acceleration of the climber 11 toward the ground 16 as compared with the acceleration of a freely falling body, so that the climber 11 is not injured when he lands.

While it is possible to use a single piece of rope, cable, or cord, to suspend the climber, it is preferred to use a combination of two. The cord 14 is lightweight but strong and may be conveniently rapidly wound around a compact spool 17 having a small moment of inertia around its axis. This allows the reeling mechanism 13 to take in slack quickly without applying a large tension which would distract or aid the climber.

The rope leader 18, on the other hand, provides a thicker more comfortable point of attachment to the climber. If a thin cord were used alone, the falling climber 11 could easily cut or bum his hands if he were to grab hold of it while falling. Alternatively, if a single thick heavy rope were used it would be necessary to use a large spool and apply a larger reeling tension to rapidly take in slack. This excessive force could be an annoyance to the climber. It is also possible to include a shock absorbing or elastic device between the rope leader and the cord.

For systems intended for use only with short walls, and systems where compactness is not an important issue, a single rope of about 10 mm thickness may be used for the entire suspension element.

The reeling device 8 may be attached to the wall 2, as shown on figure la. Alternately, it may be attached to the ceiling 21, as shown in figure lc. This positioning has the advantage that it allows the climber 22 to ascend all the way to the top of the wall 23 without interference by the reeling device 24. A pulley 25 transfers the cord 26 from the corner at the top of the wall 27 to the reel 28 without inconveniencing the climber 22. If the cord 26 were to go directly from the climber 22 to the reel 28, without the pulley 25, then the climber 22 would be disturbed by the cord 26 when he arrived near the top of the wall 23. Furthermore, the climber 22 would swing out away from the wall 23 if he fell, thus posing a danger both to himself and to any persons nearby.

We note that it is also possible to locate the reeling device on the floor or ground 24 by placing an additional lead pulley on the ceiling 21 above. This position has the advantage that the device becomes more accessible for maintenance.

Figure lc shows an additional optional feature of the fall control system, namely, a manual control cord 29 which allows the climber 22 to manually control his rate of descent. For example, as detailed more fully in figure 2, the fall control system may be designed to merely slow the climber's descent shortly after falling. In that case the climber 22 could stop his descent entirely only by pulling the cord 29 to activate an additional breaking mechanism.

Alternately, the device 28 may be programmed merely to stop the climber's fall, so that the climber 22 would be required to pull the cord 29 in order to relax the braking mechanism and allow himself to be lowered. This allows the climber to rest at a fixed position and repeatedly attempt to climb past the point of difficulty at which he fell.

In another embodiment, not shown, the device could have two cords, one for acceleration and one for deceleration.

Figure Id schematically illustrates an additional possible feature of the fall control device, a counterweight 30, which is linked to the reeling device 31 by means of a cable 32, a spool 33, a sprocket 34, a chain 35, and an second sprocket 36, so as to apply an upward tension indicated by the arrow 37, intended to assist the climber 38 in his ascent. The reeling mechanism 32 reels in slack from the cord 39 as the climber 38 ascends as before, but this time applies substantial upward force to the climber 38 produced by the counterweight 30. As before, if the climber 38 falls, the tension is increased even further to slow his fall and prevent injury.

While figures la-d show the apparatus used to top-rope belay a climber, it is noted that this device may also be used to belay a climber who is climbing above the highest point of attachment of the rope to the wall, in a process known as 'leading'. The climber would then fall down past the highest point of attachment a distance equal to the height above it to which he had climbed.

The fall control apparatus may operate by a variety of mechanisms which will be illustrated in greater detail in figures 2-4.

Figure 2 shows schematically an apparatus illustrative of the invention wherein the reeling in of slack is provided by a spring and the velocity of the faller is limited by a viscous drag mechanism, backed up by a centrifugal brake. As shown previously, the fallen climber 101 is suspended by a rope leader 102 attached to a cord 103 which may be of Kevlar or other strong and lightweight material, by means of a gated metal ring 104, known as a carabiner. The cord 103 is, in turn, attached to and wound around a spool 105.

During the climber's ascent, slack in the cord 103 is reeled in and wound around the spool 105 by torque provided by a coiled spring 106, which is attached to an axle 107 and a case 108. These are in turn affixed to the spool 105 and a supporting metal frame 109. The spring constant and length of the spring are chosen so as to provide sufficient tension to lift the weight of the cord 104, carabiner 103, and leader 102, without supplying substantial tension to the climber 101.

When the climber 101 falls, the cord 104 begins to unwind from the spool 105 thereby turning the spool 105 and the axle 107 to which it is attached. The axle 107 in turn engages a second axle 108 by means of a one way clutch 109 which may be, for example, a ratchet and pawl mechanism, or a Sprag clutch. The axle 108 is, in turn, attached to a drag mechanism 110 which slows the descent of the climber. In the embodiment illustrated here, the drag mechanism 110 comprises a drum shaped case 111, whose flat interior surfaces are studded with radially oriented rows of axially projecting blades 112; a plate 113, whose surfaces are likewise studded with radially oriented rows of axially projecting paddles 114; and a viscous medium 115 such as water, oil, or fine sand which fills the spaces between the case 111 and the plate 113. The rows of blades and paddles are complementary to one another in the sense that when the plate 113, which is attached to the axle 108 is rotated, they pass one another without colliding. The drag or friction produced by action of the viscous medium 115 on the paddles 114 and surface of the plate 113 has the effect of slowing the descent of the climber 101 as compared with that of a freely falling body, in a manner similar to that of a parachute slowing a sky diver. Alternatively, the drag mechanism 110 is a torque converter from an automatic transmission. For example, a torque converter from a General Motors automobile is suitable.

This apparatus may also be equipped with a fail-safe centrifugal brake 116 which engages upon failure of the drag mechanism 110. Such braking mechanisms are commonly used to lock automobile safety belt reels during collisions, while allowing the passengers to move comfortably in their seats during normal driving.

The one way clutch 109 shown here may be unnecessary for certain embodiments of the invention since the force produced by the drag mechanism 110 may be proportional to the angular velocity of the axle 108, or to its angular velocity squared. In such a case, the torque applied by the drag mechanism to the reel remains low when the reeling mechanism operates slowly when the climber is ascending, and only becomes substantial when the climber falls and the angular velocity of the axle increases.

It is desirable that the clutching action of the one way clutch 109 be delayed till approximately two feet of cord has played out, in order that the climber be able to lower himself rapidly from an upright position into a crouched position as is often done in preparation for a lunging move for a hold which is beyond easy reach.

Figure 3 shows schematically an alternative apparatus illustrative of the invention wherein the reeling in of slack is provided by a motor and clutch and the velocity of the faller is limited by a viscous drag mechanism, backed up by a centrifugal brake.

As shown previously, the fallen climber 201 is suspended by a rope leader 202 attached to a cord 203, which may be of Kevlar or other strong and lightweight material, by means of a gated metal ring 204, known as a carabiner. The cord 203 is, in turn, attached to and wound around a spool 205.

During the climber's ascent, slack in the cord 203 is reeled in, and wound around the spool 205 by a motor 206 which rotates a rod 207 and gear 208, which is engaged with a second gear 209 which is linked to an axle 210 by a slipping clutch mechanism, comprised of a pair of

washers 211 and bolt 212. The washers 211 are made of a material, such as rubber, nylon or teflon, which will transfer a limited amount of torque between the gear 209 and the axle 210 before slipping against the surfaces of the gear 209. The torque threshold which produces slipping of the washers 211 and disengaging of the motor 206 from the spool 205 is determined by the pressure between the surfaces of the washers 211 and the gear 209, and thus may be conveniently adjusted by tightening or loosening the bolt 212. The torque threshold is normally chosen to be just sufficient to lift the weight of the cord 203, carabiner 204, and rope leader 202, without supplying substantial tension to the climber 201. However, in certain circumstances such as when training a novice climber, or when arranging competition between two climbers of disparate abilities, it may be desirable to increase the torque threshold in order to apply substantial tension to the climber thereby aiding his ascent.

When the climber 201 falls, the cord 203 begins to apply torque to the spool 205 and unwind, thereby turning the spool 205 and the axle 210 to which it is attached. The axle 210 in turn engages a second axle 214 by means of a one way clutch 215 which may be, for example, a ratchet and pawl mechanism, or a Sprag clutch. The axle 214 is joined to a viscous drag mechanism 215 comprising: a drum shaped case 216, a series of plates 217 whose surfaces may be roughened in order to increase their drag coefficients; and a viscous medium 218, such as water, oil, or fine sand which fills the spaces between the case 216 and the plates 217. The drag produced by action of the viscous medium 218 on the surface of the plates 217 has the effect of slowing the descent of the climber 201 as compared with that of a freely falling body, in a manner -similar to that of a parachute slowing a sky diver. Alternatively, the drag mechanism 215 is a torque converter from an automatic transmission. For example, a torque converter from a General Motors automobile is suitable.

It is noted that it may be desirable to thermostatically cool the viscous medium in order to maintain a constant viscosity.

Figure 4a shows schematically an alternative apparatus illustrative of the invention wherein the reeling in of slack is provided by a weighted piston which additionally serves to produce the drag force responsible for controlling the descent of the climber.

Specifically, a weighted piston 301 is suspended on a cable 302 within a cylinder 303 which is filled with a fluid medium 304 such as air or water or oil, to form a combination reeling force and drag force mechanism. The cable 302 is transferred from piston 301 to the climber 305 by means of the pulley 306, so that as the climber climbs upward, the weight of the piston pulls it downward in the cylinder 303 maintaining the cable 302 taut against the climber 305.

As shown in greater detail in figure 4b, the piston 301 is formed so that it has a channel 307 capped by a valve 308 for allowing the passage of fluid 304 through its body, as shown in figure 4b by the arrow 309, as it is lowered by the ascending climber 305 of figure 4a. This serves to allow the piston 301 to be lowered quickly with little resistive drag force.

The apparatus is furthermore constructed so that if the climber 305 falls, the cable begins to pull upward on the piston 301 so that the passage of fluid downward through the channel 307 closes the valve 308 so that pressure builds up on top of the piston 301 forcing the fluid to pass around the body of the piston 301 through a narrow gap 310 between the piston 301 and the wall of the cylinder 303, as shown by the arrows 311 in figure 4b. Because the gap 310 is very narrow, the piston 301 exerts a strong drag force on the cable 302, thereby limiting the downward speed of the climber 305.

It is noted that the piston and climber may be linked by a more complicated spooling and ratcheting mechanism as shown in figure Id.

It will thus be seen that the invention efficiently attains the objects set forth above, in particular, providing a device for reliable automatic belay of persons climbing. It is noted that this device may be used for other purposes such as rescue of persons trapped within burning buildings.

It will be understood that changes may be made in the above construction and in the foregoing sequences of operation without departing from the scope of the invention.

For example, the reel mechanisms of figures 2 and 3 may engage an inertial device such as a flywheel, or a dynamic friction producing braking device such as a pair of mutually slipping plates pressed against each other, in order to control the descent of the climber.

It is accordingly intended that all matter contained in the above description or shown in the accompanying drawings be interpreted as illustrative rather than in a limiting sense.

It is also to be understood that the following claims are intended to cover all the generic and specific features of the invention as described herein, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.