Abstract:
The Lifesaver apparatus as herein described addresses the problem people can face in circumstances similar to those experienced by the people trapped in the World Trade Center. When lower levels in a building are inaccessible to people trapped in its upper levels, the lifesaver apparatus will provide these people with a means for escaping from the building by descending from its outside to safety.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     THIS invention relates to a lifesaver apparatus.  
         [0002]     The terrorist attacks of Sep. 11, 2001 in the United States, which destroyed the World Trade Center in New York, exposed the vulnerability of people trapped in skyscrapers. During the attacks, two airliners plunged into the two towers of the World Trade Center setting a number of its stories on fire. Large numbers of people were trapped in the uppermost levels of the towers due to the fact that the fire escapes had been destroyed on lower levels where the airliners had crashed into the towers, rendering these levels inaccessible.  
         [0003]     The result was that the trapped people could not escape from the building and died when the two towers collapsed. Since the September 11 attacks, militant extremist groups have made many threats of similar terrorist attacks, while the US Ministry of Defense has voiced its deep concern that it cannot guarantee the safety of people occupying tall buildings in the United States.  
         [0004]     It is therefore envisaged that a demand may exist for lifesaver apparatus, which allows people that are trapped in a skyscraper to flee to safety, even when lower levels are inaccessible. It will be understood that a wide range of events may render the lower levels of buildings inaccessible that need not be the result of terrorist attacks.  
         [0005]     It is an object of the present invention to address this problem.  
       PRIOR ART  
       [0006]     Various winches and safety cable devices are known in the prior art for lowering a person from high-rise buildings. Examples of these include the following U.S. Pat. Nos. 4,457,400, 6,450,293B1, 5,127,490, 4,688,659, 4,640,388, 4,588,045, 4,554,997, 4,485,891, 4,428,455, 4,385,679, 4,018,423.  
         [0007]     It is envisaged that there may be a demand for a compact portable light and cost-effective lifesaving device. It is the object of this invention to address this problem.  
       SUMMARY OF THE INVENTION  
       [0008]     1. According to the present invention there is provided a lifesaver apparatus that allows a user to exit a building by dropping from its outside walls, the lifesaver apparatus comprising a frame that is connectable to the building, the frame carrying a spool for holding a lifeline that is attachable to the user, and a clutch arrangement for controlling the rate at which unused lifeline can be unwound from the spool and supplied to the user, such that the user&#39;s rate of descent is dependant on the rate at which the lifeline is allowed to be unwound from the spool by the clutch arrangement.  
         [0009]     2. According to another aspect of the invention, the spool includes a friction clutch for controlling the rotation of the spool and the subsequent unwinding of the lifeline from the spool.  
         [0010]     3. In a first embodiment of the invention, the lifeline comprises a cord, and the clutch arrangement includes a pulley having a single V-shaped groove therein for receiving the cord from the spool. The clutch arrangement further includes a centrifugal clutch which is connected to the pulley, and which controls the rate at which the cord is fed from the spool to a user.  
         [0011]     4. In a second embodiment of the invention the clutch arrangement includes a centrifugal clutch that is connected to a pulley having two V-shaped grooves. The clutch arrangement further also includes a jockey pulley having a single groove therein.  
         [0012]     5. In a third embodiment of the invention embodiment  1  has a twin centrifugal clutch arrangement.  
         [0013]     6. In a fourth embodiment of the invention embodiment  2  has a twin centrifugal clutch arrangement.  
         [0014]     7. In a fifth embodiment of the invention the clutch arrangement includes the centrifugal clutch that is connected to a pulley that has three V-shaped grooves. The clutch arrangement further also includes a jockey pulley having two grooves therein.  
         [0015]     8. The sixth embodiment of the invention embodiment  5  has a twin centrifugal clutch arrangement. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1  shows a partial cross-sectional side view of a first embodiment of a lifesaver apparatus according to the invention generally indicated by the numeral  21   
         [0017]      FIG. 2  shows a partial cross-sectional side view of a second embodiment of a lifesaver apparatus according to the invention generally indicated by the numeral  22   
         [0018]      FIG. 3  shows a cross-sectional front view of a friction clutch spool common to embodiments  1 , 2 , 3 , 4 , 5  and  6  according to the invention  
         [0019]      FIG. 4  shows a cross-sectional side view of the spool of  FIG. 3  mounted in the lower half of the casing of embodiments  1 , 2 , 3 , 4 , 5  and  6  according to the invention  
         [0020]      FIG. 4   a  shows one end of the bottom closing-off plate according to the invention  
         [0021]      FIG. 5  shows a front view through A A of  FIG. 1  of a centrifugal clutch arrangement in embodiment  1  according to the invention  
         [0022]      FIG. 6  shows a front view through Al Al of  FIG. 2  of the centrifugal clutch arrangement in embodiment  2  according to the invention  
         [0023]      FIG. 7  shows a cross-sectional front view of the biased spring arrangement on the centrifugal clutch arrangement of  FIGS. 5 and 6  according to the invention  
         [0024]      FIG. 8  shows a diagrammatic cord path around the clutch pulley of embodiment  1   FIG. 1  according to the invention  
         [0025]      FIG. 9  shows the diagrammatic cable path around the double groove clutch pulley and single groove jockey pulley arrangement of embodiment  2   FIG. 2  according to the invention  
         [0026]      FIG. 10  shows a diagrammatic cable path around the triple groove clutch pulley and double groove jockey pulley arrangement of embodiment  5  and  6  according to the invention  
         [0027]      FIG. 11  shows a cross-sectional top view of a cable clamping device according to the invention  
         [0028]      FIG. 11   a  shows a side view of the cable clamping device mounted in the top cover plates of embodiments  1 - 6  according to the invention  
         [0029]      FIG. 12  shows the top cross-sectional plan view through the center of a twin clutch jockey pulley arrangement of embodiment  4  according to the invention generally indicated by the numeral  23   
         [0030]      FIG. 13  shows a top plan view of embodiment  2  with the top cover removed according to the invention generally indicated by the numeral  22   
         [0031]      FIG. 14  shows a top plan view of embodiment  3  with the top cover removed according to the invention generally indicated by the numeral  24   
         [0032]      FIG. 15  shows a top plan view of embodiment  1  with the top cover removed according to the invention generally indicated by the numeral  21   
         [0033]      FIG. 16  shows a top plan view of embodiment  5  of a triple groove clutch pulley, twin groove jockey pulley arrangement with one clutch according to the invention generally indicated by the numeral  25   
         [0034]      FIG. 17  shows a top plan view of embodiment  6  of a triple groove clutch pulley, twin groove jockey pulley arrangement with twin clutches according to the invention generally indicated by the numeral  26   
         [0035]      FIG. 18  shows a shock cord for use with the lifesaver apparatus according to the invention  
     
    
     DESCRIPTION OF EMBODIMENTS  
       [0036]      FIG. 1  shows a partial cross section of a first embodiment of a lifesaver apparatus generally indicated by the reference numeral  21  according to the invention having a frame, generally indicated by reference numerals  63  and  64 . Frame  63  and  64  carries a single spool  27  and a clutch arrangement generally indicated by the reference numeral  76 . Frame  63  and  64  with spool  27  and clutch arrangement  76  is enclosed in a rectangular aluminum housing  74 .  FIG. 15  is a top plan view of embodiment  1  with cover  36  removed. Frame  63  and  64  also carries a plate  62  with sides bent down and secured to frame  63  and  64  by four countersunk bolts  82  (See also  FIG. 4 ). The purpose of this plate  62  is to provide a lower cord guide hole  66 .  
         [0037]     A strong flat bar beam  75  (See also  FIG. 4 ) is provided towards the end portion of housing  74  and acts as a securing point by which lifesaver apparatus  21  can be attached to a building. The beam  75  is secured to aluminum housing  74  by way of two countersunk bolts indicated by the reference numeral  89 . Two smaller countersunk bolts  81  and two large countersunk bolts  33  and  33   a  connect frame  63  and  64  to housing  74 . The rectangular tubular housing  74  is closed off at the top by bent plate  36 . This plate also provides a top cord guide hole  67  and is secured by six countersunk bolts  85 . Below cord guide hole  67  is a cord clamp arrangement  50  and is bolted by two bolts  54  not shown in  FIG. 1  but shown in  FIG. 11  and  FIG. 11   a  which is a clearer view at right angles to the view in  FIG. 1 . A bottom closing-off plate  37  is secured in position by six countersunk bolts  80  (See also  FIG. 4 ). There are two slots  31  provided at either end of plate  37  to accommodate attachment beam  75  (See  FIG. 4   a ).  FIG. 4   a  is a partial view of plate  37  from the bottom of  FIG. 1  with beam  75  removed.  
         [0038]     Mention has to be made of the method of assembly. Firstly, bottom closing-off plate  37  is bolted into position by using six countersunk bolts  80  (See also  FIG. 4 ). A steel or stainless steel flat bar beam  75  is then pushed through two slots  31  cut out in plate  37  until the two holes in the beam align up with the two countersunk holes in casing  74 . From the access provided by the top opening two nuts and bolts  89  can be assembled and secured.  
         [0039]     Now spool  27  fully wound with cord  55  is assembled in frame  63  and  64  with two countersunk bolts  70 . Then plate  62  is bolted into position with four countersunk set-screws  82  (See also  FIG. 4 ). Then the complete clutch assembly  76  is pushed in between frame  63  and  64  and secured with two countersunk bolts  83  in frame  63  only. The end of cord  55  is passed through cord guide hole  66  and around clutch pulley  34 . Then the whole assembly is slid bottom first into housing  74  through the top opening. Then cord  55  is passed through a cord-clamping device  50  and out of top guide hole  67  in top closing-off plate  36 . Then two large countersunk bolts  33  and  33   a  and two countersunk set-screws  81  are inserted and tightened from the outside of the casing. The final assembly is complete after plate  36  is secured in position by six countersunk set-screws  85  in the same manner, as was bottom closing-off plate  37 .  
         [0040]     A lifeline  55  schematically shown on  FIGS. 1 and 8  of the drawings is wound around spool  27 . In this embodiment of the invention lifeline  55  is a synthetic cord commercially sold under the Trademarks Spectra®, Vectran® or a heat-resistant corded yarn sintered with a PTFE polymer resin sold under the trade name Fiberline®. Such cords all have a diameter of ⅛″ and a minimum breaking strength of approximately 2000 lbs. With a safety factor of 5 these cords  55  would be suitable for a person is weighing not more than 400 lbs. Thus even two people simultaneously could use the apparatus providing their combined weight does not exceed 400 lbs. For heavier loads the diameter of the cord could be increased.  
         [heading-0041]     Spool Description  
         [0042]     A cross-sectional front view of a spool  27  provided in  FIG. 3  of the drawings, shows that it is rotatably located on a stationery steel shaft  71 . Shaft  71  is secured to a frame  63  and  64  with two countersunk bolts  70  and carries a coil spring  35  as well as two friction clutch plates  29 . Clutch plates  29  are kept in contact with a brake friction disc  28  in the spool via a coil spring  35  and are prevented from rotating relative to shaft  71  by steel pins  30 , which pass through shaft  71 . A front view of a clutch plate  29  shown below  FIG. 3  reveals that it includes cutout sections, which houses steel pins  30 .  
         [0043]      FIG. 3  also shows two aluminum discs  79  having a thickness of ⅜″. Each disc  79  is provided with eight equally spaced holes. Four of these holes receive screws indicated by the reference numeral  86 , while the remainder receives screws indicated by the reference numeral  87 . Disc  79  serves to attach spool side discs  73  to a tubular spool hub  46 . Discs  79  also serve to support friction disc  28  which is trapped between disc  79  which rotates and plate  29  which is non-rotating.  
         [0044]      FIGS. 3 and 4  also illustrate the method of securely attaching the beginning of cord  55 . The cord passes through a hole  59  in a tube  46  and is looped in a circle around spring  35  and shaft  71  and crimped with a crimping lug  65 .  
         [0045]     There are two thin flat washers  51  between a disc  73  and frame  63  and  64  to prevent similar metal to metal contact between these surfaces whilst rotating. There are also two thin washers  48  at either end of spring  35 . These washers cover the slots in clutch plate  29  and make a good bearing surface with spring  35  to bear against. To unwind cord  55  from spool  27 , tension has to be applied to cord  55 . The tension in such cord will result from the weight of the user that is being supported. Clutch plates  29  are kept in contact with friction surfaces  28 , and therefore resist any rotation of spool  27 . However as soon as static friction between clutch plates  29  and friction surface  28  is overcome, spool  27  will start to rotate around stationery shaft  71 , allowing cord  55  to be unwound. To understand the first function of clutch plates  29 , mention has to be made of clutch arrangement  76  (See  FIGS. 1 and 5 ). The gist of a lifesaver apparatus  21  is to allow a user to descend from a building at a descent rate that will not injure such user. This is achieved by controlling the rate at which cord  55  is allowed to unwind from spool  27  by clutch arrangement  76 . It will be understood that should such cord be allowed to unwind uncontrollably, the user will free-fall to the ground with possible fatal consequences.  
         [heading-0046]     Slipping  
         [0047]     Such uncontrolled movement of cord  55  through clutch arrangement  76  is referred to as slipping. This result follows when there is not sufficient friction between cord  55  and the contact surfaces in clutch arrangement  76  to maintain the contact between them.  
         [0048]     In the light of what was said above it will be appreciated that it is of paramount importance that cord  55  should not be allowed to slip in clutch arrangement  76 .  
         [0049]     One way to address slip is to maintain tension between clutch arrangement  76  and spool  27  so that cord  55  is kept in contact with the contact areas in such clutch arrangement. This is achieved by ensuring that the spool  27  only rotates when a tension is applied to cord  55 . This is a function of clutch plates  29 , which prevents rotation of spool  27  when there is no tension in cord  55 .  
         [0050]     A further function of clutch plates  29  can be described by way of an example. When using lifesaver apparatus  21 , it may be desirable that spool  27  stops rotating immediately when no tension is applied to cord  55 . The reason for this is that uncontrolled rotation of spool  27  may cause cord  55  to knot and foul, rendering lifesaver apparatus  21  ineffective. This can happen when, for example, a user is evacuating a building, which does not slope vertically to ground level but which has tapering sections. In this case the user may have to land after descending a number of stories, thereafter walk on a ledge, only after which he can continue his descent to the ground.  
         [heading-0051]     Centrifugal Clutch Description  
         [0052]      FIG. 1  of the drawings shows a cross-sectional side view of a clutch arrangement  76  having non-rotating shaft  32 , bolted to frame  63  and  64  with bolts  33  and  33   a  and on which a pulley  34  is located. Pulley  34  has a V shaped groove, the base of which is slightly narrower than the diameter of cord  55 . The V shaped groove is a further measure to prevent slipping, of cord  55  in clutch arrangement  76  and is dimensioned for the specific purpose of gripping such cord in a friction fit.  
         [0053]      FIG. 8  shows a diagrammatic representation of cord  55  caught in pulley groove  34 ( 1 ) of a pulley  34  as well as the path followed by cord  55  around pulley  34 . In this embodiment of the invention cord  55  is wound approximately land ⅛ times around pulley  34 . If the pulley with the groove diameter of 1⅛″ (28 mm) is used the cord will be rotated around the pulley through an angle of approximately 400°. Cord  55  is guided to and from a clutch arrangement  76  by two guide holes indicated by the reference numerals  66  and  67 .  
         [0054]     Clutch arrangement  76  further comprises a centrifugal clutch  77 , a front view A A which is shown in  FIG. 5  of the drawings. Centrifugal clutch  77  has two heavy shoes  38  that are connected to each other via two coil springs  40  and which are also connected to pulley  34  by 4 linkages  39 . 4 Bolts and nuts  41  serve to connect  4  links  39  to shoes  38  and pulley  34 .  
         [0055]      FIG. 7  illustrates the method by which springs  40  are connected to shoes  38 . The heads of two cheese-head screws  78  locate each spring. Centrifugal clutch  77  operates on the same principal as most centrifugal clutches in that as the rotation of centrifugal clutch  77  increases, centrifugal forces that are exerted on shoes  38 , will cause the shoes to move radially outwards towards the drum. In this embodiment of the invention the drum is made from aluminum and is indicated by the reference numeral  42  (See  FIG. 5 ).  
         [0056]     The function of two biased coil springs  40  are to ensure that contact is maintained between shoes  38  and drum  42  even during periods of relatively slow rotation of centrifugal clutch  77 .  
         [0057]     Centrifugal clutch brake drum  42  is lined with a friction material  43 , which provides a friction grip between shoes  38  and drum  42 . Friction material  43  typically used is similar to that used in the motor vehicle industry to line motor vehicle brake drum and clutches. It is preferred that friction material  43  should be bonded to drum  42  and not to shoes  38 . The reason for this is that it has been found that such an arrangement reduces the transfer of heat created due to the movement between shoes  38  and drum  42  from such drum to a pulley  34 . As pulley  34  carries cord  55  which should, as a matter of caution, be exposed to as little heat as possible this arrangement is considerably preferred. Also steel shoes  38  are able to handle more heat than the lower temperature-resisting aluminum drum  42  which could become so overheated as to distort, when exposed to heavy loads off high buildings. A further measure to minimize heat transfer to cord  55  is to ensure that friction material  43  is of a lower thermal conductivity than drum  42 .  
         [0058]     In this embodiment of the invention drum  42  is manufactured from aluminum and friction material  43  is as described earlier in this paragraph. This combination has been found to have the desired performance. The effectiveness of lifesaver apparatus  21  is largely dependent on the centrifugal forces that are exerted on shoes  38  of centrifugal clutch  77 . Shoes  38  are forced against drum  42 , which in effect controls the rate at which cord  55 , which is connected to a user, is fed and thus the user&#39;s descent rate.  
         [0059]     It is a known scientific fact that the centrifugal forces that are experienced at the circumference of a rotating object are a function of the angular velocity of the object. This, in turn, is a function of the diameter of the object. In this first embodiment  21  of the invention, pulley  34  has a diameter of 1⅛″ at the bottom of the groove, which translates into an angular velocity of centrifugal clutch  77 . This is sufficient to retard the rate of descent of a  2201   b  user to approximately 6 mph. This speed should not normally cause any injuries to a user when the ground is reached after an emergency exit from a building. The impact force on landing at this speed has been calculated to be the same as that of a person jumping off an 18″ high pedestal. In order to reduce the possibility of any shock in cord  55  when a user/s commences his descent from a building a second end of cord  55  is attached to a shock-relieving device illustrated in  FIG. 18 .  
         [heading-0060]     Shock Relieving Devices  
         [0061]     A shock-cord  88  as illustrated in  FIG. 18  comprises a rubber bar  90  through which a {fraction (3/16)}″ multi-strand flexible wire cable  91  is wound. Rubber bar  90  is molded from a flexible strong rubber compound in the shape illustrated in  FIG. 90 . Flexible steel cable  91  is passed through one flared end of bar  90  and is wound several times around bar  90  before exiting out its other flared end in a similar manner. The length of cable  91  is approximately double the un-stretched length of bar  90 . Cable  91  serves as a safety measure to ensure that bar  90  does not stretch beyond its breaking point.  
         [0062]     One of the lifesaver apparatus in embodiments  1 - 6  is set up for use by a connecting bar  75  to an eye-bolt or other suitable fixtures in the building which is to be evacuated such as bed, desk, sofa etc. One end of shock-cord  88  is connected to the end of cord  55  typically by means of a snap shackle not illustrated in the drawings whilst the other end of shock-cord  88  is connected to a harness worn by the user, also not shown in the drawings.  
         [0063]     A second shock-relieving device, which would be quite suitable, is a device which is commonly used in the fall protection industry. These devices are readily available in the market and comprise of webbing material similar to that used in car safety seat belts. The webbing is sewn back on itself in such a manner that when subject to a shock-load the stitches in the webbing tear thus absorbing energy. As this device is prior art it is not necessary to further describe it other than to point out its use in this application. The device is available in a compact folded up arrangement usually encapsulated in plastic shrink-wrapping and would be attached between the second end of cord  55  and the harness that the person is using typically by means of a snap-shackle. During an emergency descent from a building a user eases himself from the building creating tension in cord  55 . The shock absorber described above cushions any possible initial shock experienced by a user as soon as cord  55  is exposed to a tension exceeding approximately 200 lbs. The tension created by the user&#39;s weight, unwinds cord  55  from spool  27 . Supply of a cord  55  to a user is controlled by clutch arrangement  76  allowing the user to make a slow automatically controlled descent to ground level. Lifesaver apparatus  21  is remained anchored to the floor or ceiling or other suitable attachment points in the building. It is important for lifesaver apparatus  21  to remain behind and attached in the building and not accompany the person descending for the following reasons: 
    1. The cord/cable will not have to carry the extra weight of the apparatus which can be up to 35 lbs in very high buildings     2. Suppose a situation should arise where the entire building is on fire and the user is forced to descend through heat and flames from burning floors below. In this case it is much better to have fresh cable passing through the flames continuously instead of a stationary cable in the flames as would be the case if the device were to be travelling with the person. If the cable were stationary the same section of cable would be exposed to continuous heat and would rapidly adversely affect its strength.    
 
         [0066]     A user would wear a harness on his/her body and his/her hands and feet would be free to allow him/her to steer himself/herself down along the side of a building towards safety. A typical body harness such as used in water-sport para sailing has been found to be effective. The harness is attached in the front and the user retains a semi-sitting position allowing use of arms and legs to gently ward off from the building during a slow controlled descent.  
         [0067]     It will be appreciated that in the event of a fire in a building, the heat of the fire may damage cord  55 . This problem can be addressed by using a steel wire cable as a lifeline. However, the steel wire cable does have two major disadvantages compared to a cord lifeline. These are mainly that steel wire cable is not nearly as flexible as the cord and secondly there is less friction between contact areas and clutch arrangements  76  and the steel wire cable, than is the case for cord  55 . The reduction in friction between contact areas could lead to the cable slipping with possible fatal consequences to a user. These characteristics of the steel wire cable necessitate changes to the construction of lifesaver apparatus  21  and will be described below:  
         [heading-0068]     Preferred Embodiment 2  
         [0069]     A second preferred embodiment, generally indicated by the numeral  22  of lifesaver apparatus  21  is illustrated in  FIGS. 2, 6  and  13  of the drawings, will now be described with reference only to the components which differ from those in the first embodiment of the invention. One solution to enhance the friction in clutch arrangement  76  and the steel wire cable is to use a jockey pulley  60  having a single groove and a pulley  58  having two grooves  58 ( 1 ) and  58 ( 2 ). Jockey pulley  60  is essential to allow the steel wire cable to make two independent turns in the two grooves of pulley  58 . It also assists to ensure that the cable does not rub against itself unduly. This will increase the friction in clutch arrangement  76   a  substantially.  
         [0070]     The path of a steel wire cable  56  is shown in  FIGS. 9 and 9   a  of the drawings. It will be noted that cable  56  makes two complete turns around pulley  58  as opposed to the single turn in the first embodiment. In  FIG. 9   a  cable  56  is fed from spool  27  through a guide hole  66  and makes an anti-clockwise turn through groove  58 ( 1 ) in the pulley  58 . Hereafter it travels to jockey pulley  60  where it makes a half anti-clockwise turn and moves to groove  58 ( 2 ) in pulley  58  in  FIG. 9  where it makes another anti-clockwise turn in groove  58 ( 2 ) where-after it exits clutch arrangement  76   a  via a guide hole  67 . Centrifugal clutch  77  and spool  27 , similar to those used in the first embodiment of the device, are incorporated in the second embodiment and need therefore not be discussed again.  
         [0071]      FIGS. 6 and 13  illustrate jockey pulley  60  located on a non-rotating shaft  68 , which in turn is located in a drum casing  42   a  and a plate  72  to support the other end of shaft  68 . Plate  72  is connected to frame  64 , which can be seen in  FIG. 2 , via two countersunk set-screws  84 . The larger countersunk set-screw  33   a  clamps rectangular tubular casing  74 , frame  64  and plate  72  to shaft  32 .  
         [0072]     The function of set-screws  33  and  33   a  is to attach clutch arrangement  76   a  to frame  63  and  64  and casing  74  and prevent shaft  32  from rotating. This embodiment  2  of the lifesaver apparatus is designated by the numeral  22  and is attached to the building and used in a similar manner as was described for the first embodiment.  
         [0073]     Tests have shown that the second embodiment of the invention is suitable for use with 7×19 multi-strand flexible wire cable, where 7×19 means  7  bundles of cable each having 19 strands.  
         [0074]     The overall diameter of the cable is ⅛″. This cable has a breaking strain of about 2000 lbs.  
         [0075]     A third embodiment generally designated by the numeral  23  of the lifesaver apparatus is shown in  FIG. 12  which is a plan cross-sectional view through the centerline of a twin clutch arrangement and jockey pulley  60 . Here twin identical centrifugal clutches  77  are used either side of a twin groove clutch pulley  58 . The operation is the same as described for embodiment  2  except that there is more braking effect because of the twin clutch arrangements which result in a slower descent rate. The path of the steel cable is identical to that already described in embodiment  2 .  
         [0076]     Similarly  FIG. 14  illustrates a fourth embodiment of the invention designated by the numeral  24  which is merely the addition of an extra clutch arrangement to embodiment  1 . Again this twin clutch arrangement reduces speed as in embodiment  3 .  FIG. 14  is a top plan view of embodiment  4  with the top cover removed. The path of the cord is identical to that described in embodiment  1 .  
         [0077]     Tests have indicated that the operation of these four embodiments is quite satisfactory. However, in order to preserve the steel cable  56  for long periods against corrosion it may be necessary to pre-grease the cable. This may affect the friction between the cable and the pulleys in embodiments  2  and  3 . Embodiments  5  and  6  illustrated in  FIGS. 16 and 17  show single and double clutch arrangements with triple groove clutch pulleys and double groove jockey pulleys.  
         [0078]     Diagrammatic path of the cable can be seen in  FIGS. 10, 10   a  and  10   b  for both embodiments  5  and  6  which results in an extra 180° turn on a clutch pulley  69 . This extra 180° turn is illustrated in  FIG. 10   a  and ensures that even with a pre-greased cable slip does not occur.  
         [0079]     The identical path of cable  56  in embodiments  5  and  6  are described as follows:  
         [0080]     The cable in each case leaves spool  27  and passes through guide holes  66  in fig  10   b . As embodiment  2  it performs one anti-clockwise turn in a first groove  69 ( 1 ) in a three groove clutch pulley  69  and then 180° around a first groove  61 ( 1 ) of the twin groove jockey pulley. It then makes a 180° turn around groove  69 ( 2 ) of clutch pulley  69  and 180° turn anti-clockwise around the second jockey pulley groove  61 ( 2 ) in a twin groove jockey pulley  61  as illustrated in  FIG. 10   a . Lastly in  FIG. 10  it makes one more anti-clockwise turn around a third groove  69 ( 3 ) in a three-groove clutch pulley and exits through guide hole  67 .  
         [0081]     Embodiments  5  and  6  are designated with numeral  25  and  26  respectively.  
         [heading-0082]     Cable Clamping Device  
         [0083]     During testing of the cable, versions of the lifesaver apparatus  22   FIG. 2 , it was found that the resilience of the cable caused it to be pulled back through the upper guide hole  67  when no tension was applied. A portion of cable was then located in an area between upper guide hole  67  and lower guide hole  66 . Often this portion of the cable formed loops and it is envisaged that these loops could in some instances prevent the cable from moving out of guide hole  67  when tension is applied again. This occurrence could jam the clutch arrangement and leave a user stranded.  
         [0084]     The problem is addressed by using a cable-clamping clamp  50  shown in  FIGS. 11 and 11   a  of the drawings which is to be mounted on the underside of the top cover plate  36  above which is the exit guide hole  67 . This is illustrated in  FIG. 2  and  FIGS. 11 and 11   a  of the drawings. The cable clamp  50  comprises a tube  78  which houses  2  jaws, a female jaw  44  and a male jaw  45  that are biased to each other by coil springs  49 . In use a single cable or cord is pinched between jaws  44  and  45  thereby preventing the cord/cable  55 / 56  from being pulled back through guide hole  67 .