This invention relates to a braking device and a descent system incorporating such a braking device which enables persons to descend from elevated locations, such as; from high rise buildings in emergency situations; from cliff faces and floating oil platforms in rescue operations; for use in lowering defence personnel and/or equipment from helicopters; as well as lowering life boats from ships and controlling the descent of lifts in case of lift cable or brake failure. The braking device is however applicable to any situation where a person, or for that matter other loads, is to be descended at a controlled rate. Background Art

In our earlier International patent application No. PCT/AU88/00218 (WO89/00063) there was disclosed a system the essence of which rested with descent down a cable or rope. Although descent systems utilising cables or ropes were well known at that time, such required some degree of training and experience in controlling the rate of descent, and thus were not suitable for escape or rescue operations. In such situations, not only are the persons involved inexperienced, but are also in a severely stressful situation, involving a degree of panic and fear generated by the danger to which they are subjected in the case, for example, of a fire in a high rise building, coupled with the necessity to escape from a particularly high location which in itself presents its own fears. In addition, in cases where the persons concerned are injured or even unconscious or semi-conscious, and therefore not in a position to control the rate of descent, then they are totally reliant on the system to lower them to the ground and also control their rate of descent. Other systems had also been proposed including the use of flexible chutes, but such systems had their limitations with regard to the height over which they can

operate and other difficulties particularly with escape from high rise buildings where fires at lower levels within the building, not only involve the existence of flames, but also the creation of unstable conditions adjacent the faces of the building as a result of updrafts of hot air.

It was therefore an object of the invention the subject of the aforementioned patent application to provide a lowering device and a descent system which in itself could control the rate of descent of a person or other load, and which was not unduly effected by the conditions in which it may be required to operate.

The invention the subject of the aforementioned international patent application therefore envisaged a lowering device adapted in use to engage a cable or rope of a twisted configuration, and comprising an inner rotatable means surrounding and engaging said cable or rope to follow the twist therein and thereby rotate about the cable or rope as it descended down the cable or rope. The rotatable means were supported by, and rotatable within, an outer housing having means to support a load therefrom, and means for controlling the speed of rotation of the rotatable means and therefore the rate of descent of the lowering device down the cable or rope.

With such a lowering device, although the inner rotatable means was free to rotate about the cable or rope as it descended, the weight of the person hanging on the outer housing held the outer housing against uncontrolled rotation about the cable or rope and thus the persons being lowered maintained a fixed position relative to, and supported by, the cable or rope as they descended.

The invention also envisaged a system for descending from elevated locations, including a lowering device as described above, and a cable or rope adapted to extend from the elevated location to anchor point at ground level.

Preferably the means for controlling the speed of rotation of the inner rotatable means was a closed circuit

gear pump driven by the inner means and forming part of a hydraulic circuit containing a constriction to control the speed of the pump and therefor the speed of rotation of the inner means and also therefor the speed of descent. Alternatively, the means for controlling the speed of rotation of the inner rotatable means may have been centrifugal brake rotating with the inner means and engaging the outer housing with a force which increased and decreased with increasing and decreasing speed of rotation to maintain a relatively constant speed of rotation and therefore speed of descent.

Preferably the system included means to support a person carried by the lowering device and in the form of a support bar detachably connected to the outer housing and to which the person was strapped.

Preferably the support bar was attached at its upper end to the housing and at its lower end to a guide sleeve adapted to surround the cable or rope, and carried means at its lower end to engage beneath the buttocks of the person, together with handle means extending away from the support bar approximately mid way along its length and to be grasped by the person, with strap means also carried by the support bar and to be received and fastened about the body of the person. Preferably the cable or rope was stored on a pulley system located at the elevated location from which it was unwound and lowered to ground level for attachment to an anchor point, and the pulley system incorporated means to progressively transfer a plurality of lowering devices in turn along the cable or rope to a loading station at which the support means, and associated persons, were in turn coupled to the lowering devices to descent down the cable or rope.

Preferably the loading station was situated at the end of a platform means adapted to extend beyond the elevated location. Disclosure of the Invention

It is an object of the present invention to provide a braking device, which may be a lowering device, and which involves an alternative speed control means to the closed circuit gear pump or centrifugal brake, and associated with either a twisted cable or rope along, or down, which the device travels in a manner similar to that disclosed in the aforementioned international application, or associated with a reel around which a cable or rope is wound or a pulley over which a cable or rope is trained. The invention therefore envisages a braking device, comprising a housing and a rotatable shaft within said housing, at least one annular disc member carried by said shaft to extend radially away therefrom and rotatable therewith, and at least two annular spacer plates fixed to said housing to extend radially inwardly therefrom and between two of which the, or one of, said annular discs extend, said housing adapted to be filled with a liquid whereby the cohesion between the liquid and the facing surfaces of the, or each, said disc and the spacer plates on either side thereof act to brake the speed of rotation of said discs and said shaft and as such any device with which the shaft maybe associated. Brief Description of the Drawings

Three preferred embodiments of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a vertical sectional view of a lowering device in accordance with a first embodiment of the invention and co-operating with a cable or rope; Figure 2 is a vertical sectional view of a lowering device in accordance with a second embodiment of the present invention;

Figure 3 is a side elevational view of a lowering device in accordance with the embodiment of Figure 1 in association with support means for a person;

Figure 4 is a plan view of the support means of Figure 3, without an occupant;

Figure 5 is a vertical sectional view of a lower guide sleeve or runner forming part of the support means of Figures 3 and 4;

Figure 6 is a plan view of the lower guide sleeve or runner of Figure 5;

Figure 7 is a side elevational view of a storage room within a high rise building incorporating a pulley system for the cable or rope down which persons are to descend suspended form a lowering device in accordance with Figure 1, together with a loading station provided at the outer end of an extendable platform means;

Figure 8 is an end elevational view of a sheave forming part of the pulley system of Figure 7 and for transferring lowering devices, in turn, along the cable or rope to the loading station;

Figure 9 is a side elevational view of the sheave of Figure 8;

Figure 10 is a plan view of the extendable platform forming part of the system of Figure 7; Figure 11 is a side elevational view of an anchor device for anchoring the lower end of the cable or rope at ground level;

Figure 12 is a vertical sectional view of a lowering device in accordance with a third embodiment of the present invention, and

Figure 13 is a cross-sectional view taken along line 13-13 of Figure 12. Best Modes for Carrying out the Invention

Figure 1 of the drawings illustrates a braking device or speed control mechanism D in accordance with the first embodiment of the invention, and as an alternative to the closed circuit gear pump disclosed in our aforementioned patent application, and which, as with our aforementioned international patent application, is adapted to engage and move down a cable or rope of twisted configuration and from which device a person or load is suspended.

As with the device of the aforementioned international patent application, the braking device D comprises an inner rotatable sleeve 141 surrounding a cable (not shown) down which the device is to travel. The cable is formed from a plurality of spirally wound or twisted cable strands and the inside of the inner rotatable member is correspondingly shaped to follow the spiral configuration of the wound or twisted cable strands.

The sleeve 141 is surrounded by a main housing 142 of inverted cup-shaped configuration and through the centre of which the sleeve 141 with its cable passes. In addition, a thrust bearing 143 is received and retained between a ledge 145 around the sleeve 141 and the end of the housing 142. The lower end of the cup-shaped housing 142 is closed by a dished end wall 146 threadably attached thereto at 147. The sleeve and cable combination passes through the centre of the end wall 146 and a bearing 148 is received and retain in a circumferential recess 149 on the inside of the end wall. O-ring seals 150 are also interposed between the end wall 146 and the sleeve 141 therethrough.

The braking device D further comprises a plurality, in this case three, annular discs 150 surrounding and keyed to rotate with the sleeve 141 and axially spaced apart from each other. The discs 150 are received and rotate between a plurality of annular spacer plates 151, in this case four plates to overlap and underlap the three discs 150, and coupled together via spacer portions 152 and bolted by bolts 153 to the end wall 146 to thereby be fixed to the housing 142. A small gap is as a result formed between the faces of the discs and the adjacent faces of the spacer plates. The housing 142 is filled with hydraulic fluid, such as oil, and the cohesion between the fluid and the facing surfaces of the discs 150 and spacer plates 151 acts to brake the speed of rotation of the discs and as a result the rotation of the sleeve 141 and the speed of descent of the device down the cable.

Over long descent distances for the device some warming of the hydraulic fluid may occur thus lessening the viscosity of the hydraulic fluid and the cohesive effect between it and the faces of the discs 150 and spacer plates 151. To compensate for this the discs 150 are formed from aluminium and the spacer plates 151 from steel, and as the hydraulic fluid warms the discs 150 being of aluminium, and in contact with the hydraulic fluid, expand to a greater extent than the spacer plates which are also contact with the fluid, and as a result the gaps between the faces of the discs and the plates reduces to maintain the cohesive effect between the fluid and the faces of the discs and plates.

Figure 2 of the drawings illustrates a combination of a reel 100 for the cable, with a braking device D similar to that of Figure 1, and in which where applicable the same reference numerals have been used for the braking device of Figure 1.

In this embodiment, the braking device D has only two discs 150 and three co-operating spacer plates 151 and the housing 142 of the braking device is attached directly to a connecting plate 107, whilst the spacer plates 151 are attached together by bolts 153 extending through the connecting plate and then through the spacer plates 151. The discs 150 are in turn rotatably attached to the shaft 111 of a reel 100.

The reel assembly 100 comprises a reel housing 101 associated with the braking device and the shaft 111 has mating hexagonal formations whereby rotation is transmitted from the drive shaft to the braking device and vice versa. The shaft 111 is mounted at one end in the bearing 143 and at an intermediate position in a bearing 113 received within connecting plate 107 and a bearing housing 114 also mounted on the connecting plate 107. The bearing housing 114 also incorporates "O" ring seals 115.

The other end of the shaft 111 is received within and connected to a central drive sleeve 116 for the reel

100, which sleeve is in turn connected at one end to one annular side wall 117 of the reel 100 and at its other end to an annular plate 118. The shaft at this point may have a hexagonal cross-section cooperating with a mating hexagonal cross-section of the interior of the sleeve 116 to allow rotation of the shaft 11 to be transmitted to the sleeve 116 and therefore the reel 100, and vice versa.

The peripheral edge of the annular plate 118 is connected to a cylindrical cable drum 119 around which a cable 120 is wound between the annular side wall 117 of the reel 100 and a second annular side wall 121 for the reel with the cable drum 119 extending between and connected to the respective annular side walls 117 and 121. The annular plate 118 is spaced axially inwardly of the side wall 121 thereby defining a chamber within which the bearing housing 114 is received.

The reel housing 101 at the side thereof remote from the braking device is closed by a shallow cup-shaped closure member 122 screw threaded or otherwise attached at 122a around the end of the reel housing 101 and having a central bush 123 which rotatably receives the extreme end of the shaft 111.

In addition to the controlled braking provided by the braking device, a mechanical braking mechanism may also be provided acting directly on the reel, and being in the form of a friction brake consisting of a brake disc 130 surrounding the bush 123 and axially slidable therealong under the action of a pair of cam operated members 132 with an operating lever 131 which act on the brake disc to move it into and out of engagement with an annular pad 133 of brake friction material on the annular side wall 117 and still further into and out of engagement, via the reel which is axially slidable on the shaft 111, with an annular pad 134 also of brake friction material on the connecting plate 107.

The lowering devices of the embodiment of Figure 1 and 2 may have a connecting lug formed on the outside

surface of the housing 142 or 101 with a T-shaped slot or keyway being provided for engagement by a latching member forming part of a support frame to be later described.

Turning to Figures 3 to 6 of the drawings, the lowering devices, in accordance with the embodiment of Figure 1, is associated with a support frame 300 for suspending a person from the device as it moves down the cable. The support frame comprises an elongate support bar 301, the upper end of which carries a T-shaped latching member matching the T-shaped keyway of the lowering device referred to above in connection with the embodiment of Figure 5. The lower end of the support bar carries a seat 302 to engage beneath the buttocks of the occupant using the descent system, whilst approximately midway along the length of the bar a sub-frame 303 provides a pair of handles 304, one on either side of the occupant, and which are to be grasped by the occupant as shown. The support frame 300 is completed by a pair of straps 305 and 306 which are received to be fastened about the torso and the hip area respectively of the occupant.

The coupling of the support frame 300 to the cable, apart from via the lowering devices, also includes guide sleeve or runner 307 (see Figures 5 and 6) . The guide runner 307 comprises an inner rotatable sleeve 308 internally profiled at upper and lower end portions 308a and 308b to match and engage the spiral or twisted profile of the cable, whereby, when the runner 307 is down the cable, the inner sleeve 308 will rotate about the cable as it follows the spiral or twisted path of the cable strands. The runner is completed by an outer housing 309 surrounding the inner sleeve which rotates within the outer housing. The outer housing carries a connecting lug 310 have a T- shaped slot or keyway 311 formed vertically downwardly therethrough from an opening at the top of the lug but terminating short of the lower end and in which a mating T- shaped latching member carried by the lower end of the support frame 300 is received. The runner 307 is coupled

to the lowering device by a flexible tether 312 to keep the lowering device and the runner together as a combination.

Alternatively the support frame 300 may be replaced by a capsule coupled to the lowering device and in which the person is seated and enclosed, and which will afford protection if flames or other injurious or hazardous conditions exist in the path of descent.

Figure 7 of the drawings represents a schematic side elevational representation of a storage room 313 within a high rise building for storing the descent system, comprising the cable, a plurality of lowering devices D, each in combination with a runner 307, together with support frames 300 to complete the system.

The cable and a plurality of lowering device/runner combinations are stored on a pulley and sheave system within the storage room 313, which room is suitably fire rated, and which has access to the outside of the building via a removable wall panel (not shown) when the system is required to be used. The floor 314 of the storage room 313 carries a platform 314a mounted on rollers 315 engaging appropriate rails whereby it can be extended to a position with its outer end extending beyond the side of the building. The platform incorporates a trap door 316 which, when a person has been strapped into the support frame 300 and the frame is attached to a lowering device/runner combination, will then be swung downwardly open to allow the person to drop through the platform and descent down the cable (see also Figure 14) . The outer end of the platform may also carry a hand rail 317. The pulley and sheave system within the storage room comprises a main drum 318 for the cable and from which it will be unwound when required. The cable extends around a pair of intermediate sheaves 319 and 320 to a transfer sheave 321 also mounted on a frame 322 carrying rollers 323 engaging rails to allow the transfer sheave to be extended out beyond the wall of the building to a position above the extended platform.

The transfer sheave 321 provides for the transfer of lowering device/runner combinations along the cable from a storage position on the cable between the transfer sheave 321 and the preceding intermediate sheave 320. The transfer sheave 321 comprises a pair of parallel spaced apart side plates 324 carried by a freely rotatable axle 325, and shaped at four positions at 90°C to each other to provide recesses 326 within which a lowering device/runner combination will be received as they are advanced along the cable when the sheave is rotated. The radially protruding sections 327 of the side plates 324 progressively engage the combinations as the sheave rotates to transfer them, in turn, along the cable 1 at a time to the platform. The cable is, in turn, trained around a plurality of guide rollers 328 the axes of which lie on the arc of a circle, and each guide roller extends between the protruding sections 327 of the side plates 324.

When the descent system is in use, cable is unwound form the main storage drum 318 over the sheaves and its free end lowered to ground level, where, with reference to Figure 11 of the drawings, it is connected to an anchoring device 330 provided at footpath or road level. It is envisaged that, if the positioning of the anchoring device 330 relative to the side of the building is such that the cable, when anchored, will adopt an inclination of in the order of 5° to the vertical, the weight of the person suspended from the lowering device will be sufficient to hold the outer housing of the lowering device stationary such as to not rotate with the rotating inner sleeve, and thus the person descending will not rotate about the cable. The anchoring device 330 comprises a pair of clamps, namely, an upper clamp 331 and a lower clamp 332, both of which are mounted to pivot toward and away from the end of the cable. As persons descend and reach ground level they are released from the lowering device/runner combinations, and a number of such combinations will accumulate at the end of the cable. The

accumulated combinations can be removed by releasing the upper clamp 321 from the cable to allow a combination to drop to the lower clamp 322, whereafter, if the upper clamp 321 is reclamped to the cable, the lower clamp can then be released, and the combination taken off the end of the cable. The process is repeated periodically, or continuously, to remove the combinations as they accumulate at the lower end of the cable.

Figures 12 and 13 of the drawings illustrates a combination of a pulley about which the cable is trained, with the braking device of the present invention, and in which, where applicable, the same reference numerals have been used for the braking device of Figure 1.

In this embodiment, the braking device has only one disc 150 and two co-operating spacer plates 151 and the housing 142 of the braking device is attached directly to connecting plate 107 and locked in place by a grub screw 107a, whilst the spacer plates 151 are attached together by bolts 153 extending through the connector plates and then into the connecting plate 107. The disc 150 is inturn rotatably attached to a shaft 111.

The connecting plate 107 is in turn connected a housing 400 for a pulley 404 which in turn is rotatably coupled to the shaft 111 via a gear train consisting of a gear 401 carried by the shaft 111 and meshing with a gear 402 coupled to the pulley 404 by bolts 405 and freely rotatable with a shaft 403 within the housing 400. A pair of pressure pulleys 406 rotatable with shafts 408 within the housing 400 apply pressure to a cable (not shown) trained around the pulley 404 and to maintain the cable in tight engagement around the pulley 404.

In this embodiment, with the device suspended via connecting lugs 407, carried by the housing 400, from an elevated position, and with a cable or rope trained around the pulley 404 and held an engagement therewith by the pressure wheels 406, a person or object attached to one end of the cable or rope can be lowered from the elevated

position under control of the braking device, and upon reaching a lower position, such as the ground, the other end of the cable upon reaching the elevated position can be coupled to another person or load whereafter to be lowered by reverse movement of the cable around the pulley 404.