AU653576B2 - Descent apparatus - Google Patents

Description

"DESCENT APPARATUS" This invention relates to descent apparatus.

This invention has particular but not exclusive application to descent apparatus suitable for providing emergency exit from burning buildings and the like, and for illustrative purposes reference will be made to such application. However, it is to be understood that this invention could be used in other applications, such as in abseiling or other descent sports.

:eoeoo Many means of escape from burning buildings have been 10 proposed. For example it has been proposed to utilize abseiling type descent equipment to be stored in an emergency eeI cupboard against the requirement for an individual to make a descent from a building window or the like. Such equipment cannot be used by untrained personnel and carries with it the requirement that the user, under extreme duress, must recall the training in order to effect a safe descent. Other apparatus proposed for use and requiring less training includes the use of clutches and the like acting on a descent line.

For example, Australian Patent Specification No. AU-A- 21723/83 discloses apparatus comprising a housing having spooled therein a steel descent tape. In use the tape is attached to the structure and the housing is attached to the user via a harness. Descent is controlled by an adjustable brake, and heat generated by friction through the brake is dispersed into a coolant substance dispensed simultaneously with the tape. However, such apparatus has proved to be expensive to the point that large numbers would be uneconomic to install in most buildings and therefore are generally unsuited for provision as a personal descent device for all expected building personnel.

The present invention aims to substantially alleviate the above disadvantages and to provide descent apparatus which will be reliable and efficient in use. Other objects and advantages of this invention will hereinafter become apparent.

With the foregoing and other objects in view, this invention in one aspect resides broadly in descent apparatus including:a body member defining an enclosed coiled path adapted to receive a descent rope for friction retarded passage therethrough; 15u securing means for securing said body member to the user, and guide means for said descent rope located at an end of said coiled path.

The descent member may take any form consistent with the S: 20 function of providing a transit line from the top of the descent to the bottom and as such will be selected according to •eg.

the circumstances of the descent. For example, the descent meniber may be selected from ropes of natural or synthetic fibre, wire ropes or the like. Preferably, the descent member is flexible rope such that it may be conveniently stowed.

In order to reduce the risk of injury to the user, and to provide both long storage life and ease of handling, it is preferred that the descent member be selected from synthetic

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3 fibre ropes. Preferably, the synthetic fibre rope is selected from those having a degree of inherent stretch, such that sudden arrest of descent may be cushioned.

The rope is preferably terminated at its upper end by fixing means adapted to permit attachment of the end of the rope to a strong point or the like such as the structure or whatever is at the top of the descent and available to secure the rope during the descent. The fixing means chosen will of course be determined by the nature of the substrate to which it is to be attached. Preferably, the building structure is provided with attachment points at one or more apertures of the building such that the fixing means may comprise a simple snap hook or the like.

The body member may be of any form dictated by the path 15 defined therein for frictionally resisted passage of the elongate descent member. For example, where the path comprises a conduit of frictional fit about the descent member, the body member may comprise a simple pipe or tube. In order to maintain the functional simplicity of the apparatus, a unitary *20 body

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e oeoo member may be provided wherein the friction provided to frictionally resist passage of the descent member is inherent in the material of the body member about the path.

Preferably, the body member is such that the path utilizes the belaying characteristics of the preferred rope descent members to create friction to inhibit descent. For example, the body member may comprise a drum arrangement having a helical rope path machined or cast about the outer surface thereof and preferably having rope retaining mel to retain 10 the rope in the path and to thereby prevent both disengagement of the rope from the body and locking of the rope against itself in use.

o.oe.: Preferably, the body member comprises a tubular body of high polymer, stainless or other steel, copper or any other S 15 suitable metal or plastic engineering material. In order to provide compactness for the apparatus and to utilize the belaying characteristics of the preferred rope descent members, it is preferred that the tubular body be coiled about an axis which is substantially transverse to the descent member in use.

20 The number of coils required to provide the desired frictional resistance to descent under the weight of the user will depend upon the weight and the relative frictional characteristics of the rope and the tube in terms of both naterial and tightness of fit.

Preferably, the coiled body member is secured between adjacent coils to provide strength and rigidity and to thereby reduce the gauge of tubing required to resist straightening of the apparatus in use.

The theoretical measure of resistance to uncontrolled descent may be expressed as the ratio of the tension in the rope above the body member in use to that to be applied to the rope below the body member, and obeys the following relation:- Tt eie Ts Where: Tt Tension in the rope on the tight side.

Ts Tension in the rope on the slack side.

p The coefficient of friction between the rope and the tube wall.

8 The total angle of wrap of the rope expressed in radians.

In practice, it has been determined that the theoretical relationship is conservative and that accordingly less tension o S Ts is required to halt descent than is predicted by the theoretical model.

In general, it has been determined that particularly useful apparatus includes for example a descent member of eight to eleven millimetre nylon rope threaded through a body member S" comprising from three to five turns of twelve to fourteen millimetre internal diameter copper, steel or stainless steel tube to form a cylindrical body of about one hundred millimeters internal diameter.

The guide means may take any form consistent with the function of orienting the body member with the descent member to facilitate at least the leading in or the leading out of the descent member to the descent member path. Preferably, guide 6 means is provided to guide the descent member both into and out of the path. The guide means selected will of course depend upon the nature of the descent member and the body member.

For example, where the body member comprises the helically grooved cylindrical body hereinbefore described, the guide means may comprise a pair of ferru.es mounted to the body member and adapted to orient the body member with its cylindrical axis substantially transverse to the line of the descent member. Alternatively, in the case of the coiled 10 tubular body member preferred hereinbefore, the guide means may comprise an extended portion of the tube provided at one or both of the descent member inlet end or outlet end of the body and oriented such that the guide means aligns the descent member to be substantially transverse to the axis of the helical form of the body member.

Preferably, the guide means includes a flared portion at its outer extremity to both facilitate passage of the descent member into the body member and to ameliorate the tendency of the descent member to chafe in use, which tendency may arise S" 20 where the descent member is bent or deflected about the end of the guide means.

The securing means may take any suitable form such as an attachment point for a hand grip, bosun's chair, harness or stirrup and strap. Preferably, the securing means comprises an attachment point disposed on the body member at a point about mid way between the descent member inlet and outlet to the body member. For example, in the case of the preferred coiled tubular body member the securing means may comprise a lug or eye brazed, welded or otherwise affixed to the coils of the body member and adapted to receive user supporting means such as that described above by means of a snap, D or other shackle.

In a further aspect, this invention resides broadly in a method of descending such as from a burning building or the like and including the steps of:obtaining the aforedescribed apparatus; securing an end of said descent rope; attaching the user to said securing means; maintaining sufficient tension in the free end of said descent rope to control the rate of, passage of said descent rope through said path, and descending down said descent rope suspended from said 15 securing means.

In order that this invention may be more easily understood and put into practical effect, reference will now be 9 a made to the accompanying drawings which illustrate a preferred embodiment of the invention, wherein:- FIG 1 is a side view of apparatus in accordance with the present invention; FIG 2 is an end view of apparatus in accordance with the present invention.

In the figures there is provided a nylon rope descent member 10 of 11 mm diameter and adapted to be affixed at its 4^

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upper end to a support capable of supporting the weight of a user suspended by the nylon rope descent member 10. The descent member 10 is passed through a helical tubular body member 11 comprising three coils of copper tube having an internal diameter of 12 mm and having a coil internal diameter of 100 mm. The coils of the body member 11 are welded together at 12 to provide strength, rigidity and resistance to straightening of the body member 11.

The outer ends of the body member 11 are configured such 10 that they form an upper outlet 13 and a lower outlet 14 disposed such that the descent member 10 enters and exits the body member 11 in substantially the same vertical plane. To guide the descent member 10 into and out of the body member 11 the body member 11 is formed with upper 15 and lower 16 guide o.

15 portions serving to assist in maintaining the linearity of the body member 11 with the descent member A D-ring 17 is brazed to the body member at a point approximately equidistant in a vertical plane between the upper outlet 13 and the lower outlet 14, the D-ring 17 being adapted to receive a snap-shackle or the like for attachment of the user by means of harness, stirrup or strap or the bosun's chair (not shown).

In use, the rope descent member 10 is threaded through the device for storage such that the apparatus is configured for immediate use when needed. The upper end of the descent member is either permanently made fast to a predesignated strong point or alternatively, the user may attach the upper end to a bed, 9 handrail balcony or other strong point capable of supporting the load of the user.

The apparatus may have its D-ring permanently shackled to the bosun's chair, harness or stirrup and strap, or may be snap shackled or D-shackled thereto by the user prior to use. The user may then step into the harness or the like, and slide the apparatus up the rope to a convenient position for commencing the descent.

The free end of the descent member 10 may then be draped 10 drown the descent route, and the descent commenced. The user takes a firm hold of the rope just beiow the device. To lower, ge'. the user feeds the rope into the body member at a speed satisfactory to safety. To stop, increasing tension T s adds to and increases the frictional force in the apparatus to 15 oppose tension Tt and cancel the tendency of the apparatus to move along the descent member 10. To lower again, the user eases the tension T s on the rope.

The operating principle of apparatus in accordance with the abovedescribed embodiment is similar to that of a belaying 20 point where a rope is wound around a fixed shaft a number of times and used to lower large masses by using the friction that develops between the rope and the shaft to supply the required braking force. The tension T. in the slack side of the rope which is provided by the operator is a fraction of the weight being lowered. The additional tension is supplied by friction between the stationary body member 11 and the descent member as it slides around within the path defined within the body member 11.

The coil of the body member 11 is surprisingly discovered to emulate the advantageous features of a belaying pin with the advantage of ensuring a guided path for the rope thus eliminating the tendency for the rope to jam by one layer of rope climbing up on another.

The coil of the body member 11 provides u convenient anchoring point to which harness can be attached as well as providing a hand grip for the operator which steadies the 10 operator and gives a sense of security.

The following Table 1 includes theoretical and 4 experimental results that were obtained by attaching a load to the apparatus and measuring the slack-side tension required to just hold the load.

15 TABLE 1 Mass of Person Three-turn Four-turn Five-turn Coil Coil Coil (kg) (N) 74 [60] 40 [12] 21 S 20 60 89 48 104 [89] 56 [24] S' 80 119 64 34 134 [118] 72 [47] 38 100 149 79 42 110 164 87 47 120 179 [1622 95 [75] 51 130 194 103 140 209 111 59 150 223 119 64 The numbers in square brackets are experimental results that were obtained for abovedescribed three coil apparatus and a similar four coil apparatus, each utilizing a nylon rope in a copper tube. The figures give the slack side tension Ts tension that a person operating the device would be required to provide to just hold the device when a specified mass is suspended from the device.

It has been found the average person of 80 kilograms or less operating a four-turn model of the device are required to maintain a tension of less than 64 newton to hold their own weight. The apparatus in accordance with the present 10 embodiments also possess the advantageous feature of the user having fine control over the rate of descent. The apparatus provides a simple, cheap and safe method of escaping from a building that is being engulfed in flames where all other avenues of escape have ceased to exist.

15 It will of course be realised that while the above has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as

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would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as 20 defined in the appended claims.

Claims (12)

1. Descent aprparatus including:- a body member defining an enclosed coiled path adapted to receive a descent rope for friction retarded passage therethrough; securing means for securing said body member to the user, and guide means for said descent rope located at an end of said coiled path.

2. Descent apparatus according to Claim 1, wherein said descent rope is selected from ropes of natural or synthetic fibre.

3. Descent apparatus according to Claim 2, wherein said descent rope is terminated at its upper end by fixing means facilitating attachment of the rope at the descent site.

4. Descent apparatus according to any one of the preceding Claims, wherein said body memner comprises a tubular body of high polymer, stainless or other steel, copper or any other suitable metal or plastic engineering material, said tubular body being coiled about an axis which is substantially transverse to the descent rope in use.

Descent apparatus according to Claim 4, wherein each coil of said coiled body member is secured to its adjacent coils.

6. Descent apparatus according to any one of the preceding Claims, wherein one said said guide means is provided at each end of said path to guide the descent rope both into and out of the path.

7. Descent apparatus according to Claim 6, wherein said body member is of coiled tubular form and wherein said guide means comprises extended end portions of the tubular body member and oriented such that the guide means aligns the descent rope to be substantially transverse to the axis of the helical form of the body member.

8. Descent apparatus according to Claim 7, wherein said guide means includes a flar-ed portion at its outer extremity.

9. Descent apparatus according to any one of the preceding Claims, wherein said securing means may takes the form of an attachment point for a hand grip, bosun's chair, harness, or stirrup and strap.

Descent apparatus according to Claim 9, wherein said securing means comprises an attachment point disposed on the outside of the body member at a point about mid way between the respective ends of said path. 14

11. A method of descending such as from a burning building or the like and including the steps of:- procuring apparatus in accordance with any one of Claims 1 to securing an end of said descent rope; attaching the user to said securing means; maintaining sufficient tension in the free end of said descent rope to control the rate of passage of said descent rope through said path, and descending down said descent rope suspended from said securing means. .n

12. Descent apparatus substantially as hereinbefore described with reference to the accompanying drawings. .o DATED THIS Fourth DAY OF August, 1994. *0o HENRY ROBERT BEAK by PIZZEY AND COMPANY PATENT ATTORNEYS .4*