Patent Publication Number: US-2022219945-A1

Title: Self-climbing elevator machine room for use during the construction of a building

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of PCT International Application No. PCT/EP2020/080383 which has an International filing date of Oct. 29, 2020, and which claims priority to European patent application number 19206416.0 filed Oct. 31, 2019, the entire contents of both of which are incorporated herein by reference. 
    
    
     FIELD 
     The invention relates to a self-climbing elevator machine room for use during the construction of a building. 
     BACKGROUND 
     Elevators are needed in the construction stage of especially high-rise buildings to transport constructors and/or equipment to the floors in the building. Mechanics working on completed floors and constructors working on floors to be completed should be able to use the elevator. 
     A prior art jump-lift may be used in the construction stage of the building. The hoisting height of the elevator may be increased in steps of one or more floor levels each time the building has reached a predetermined height above the previous jump. The elevator machine room may be transported upwards in steps. The shaft must, however, be provided with special interfaces in this prior art arrangement. The elevator machine room is anchored to special anchoring points made beforehand to the walls of the shaft along the height of the shaft. 
     SUMMARY 
     An object of the present invention is to present a novel self-climbing elevator machine room for use during the construction of a building. 
     The self-climbing elevator machine room for use during the construction of a building is defined in claim  1 . 
     Prior art jump-lift concepts used in high-rise buildings are complex and expensive. The number of floors that cannot be serviced with the elevator car in prior art jump-lifts may be 4-5. Prior art jump-lift concepts further use intermediate platforms (crash decks) above the installation platform and below the deflection deck (provided by the building constructor) in order to prevent objects and material from falling in the shaft. 
     The novel arrangement will render some of the crash decks redundant. A crash deck is not needed between the two decks in the elevator machine room. The position of the deflection deck may be raised as the slip casting of the shaft proceeds. 
     The novel arrangement reduces the number of floors that cannot be serviced to a minimum by integrating some key functions. The self-climbing elevator machine room requires only a limited space in the vertical direction in the shaft. The self-climbing elevator machine room may thus be installed into the shaft at an early stage of the construction of the shaft and the building. The self-climbing elevator machine room may also be used near the top of the already constructed shaft. An elevator supported on the self-climbing elevator machine room may operate to a height of two landings below the top of the already constructed shaft. 
     The self-climbing elevator machine room may be prefabricated and assembled into a transportable module at factory premises. The produced module may then be transported to the construction site with conventional transport methods. The module may be lifted into the pit in an early stage of the construction of the shaft and the building. The use of the module may be started when the shaft has reached a height in which the elevator is needed. 
     There is no need for special interfaces in the walls of the shaft when the self-climbing elevator machine room according to the invention is used. The self-climbing elevator machine room may climb on the guide rails already installed. The self-climbing elevator machine room may also be locked in place in the shaft only through the guide rails and/or through fish plates associated with the guide rails in the shaft. There is no need for pockets in the shaft for the climbing and/or suspension process. The invention may be used in connection with any floor to floor distance in the building. 
     The self-climbing elevator machine room is re-usable. The self-climbing elevator machine room may be removed and transported to another construction site when the self-climbing elevator machine room is not any more needed at the first site. 
    
    
     
       DRAWINGS 
       The invention will in the following be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which: 
         FIG. 1  shows a cross-sectional view of a self-climbing elevator machine room, 
         FIG. 2  shows an axonometric view of a self-climbing elevator machine room, 
         FIG. 3  shows an axonometric view of a first portion of the self-climbing elevator machine room, 
         FIG. 4  shows an axonometric view a second portion of the self-climbing elevator machine room, 
         FIG. 5  shows a view of first locking means, 
         FIG. 6  shows a view of second locking means, 
         FIG. 7  shows a side view of a second lifting means, 
         FIG. 8  shows a first side view of a third lifting means, 
         FIG. 9  shows a second side view of the third lifting means, 
         FIG. 10  shows a third side view of the third lifting means, 
         FIG. 11  shows a side view of a fourth lifting means, 
         FIG. 12  shows an enlargement of a lower portion of the lifting means shown in  FIG. 11 , 
         FIG. 13  shows an enlargement of an upper portion of the lifting means shown in  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a cross-sectional view of a self-climbing elevator machine room. 
     The self-climbing elevator machine room  100  is shown in a shaft  20  with guide rails  25  supported with brackets  26  on the walls  21  of the shaft  20 . The guide rails  25  may be formed of guide rail elements. The opposite ends of two consecutive guide rail elements may be connected with guide rail fixing means. The guide rail fixing means may be formed of connecting elements, e.g. fish plates  27 . The guide rail elements may have a certain length e.g. 5 meters. The guide rail elements may be attached with guide rail fixing means e.g. brackets  25  to the walls  21  in the shaft  20 . There may be brackets  25  near both ends of the guide rail elements. The figure shows only a bottom portion of the shaft  20 . 
     The self-climbing elevator machine room  100  may comprise two decks  110 ,  120 . The two decks  110 ,  120  may be positioned upon each other in a vertical direction S 1 . 
     The lower deck  110  may be provided with upwards extending support means  140  and the upper deck  120  may be provided with downwards extending support means  150 . The upwards extending support means  140  are firmly attached to the lower deck  110  and the downwards extending support means  150  are firmly attached to the upper deck  120 . The support means  140 ,  150  extend around the guide rails  25 . The support means  140 ,  150  may be provided with guide means  160  acting on the guide rails  25 . There may be several guide means  160  along the height of the support means  140 ,  150 . The use of several guide means  160  along the height of the support means  140 ,  150  will stabilize the deck  110 ,  120  horizontally on the guide rails  25 . The outer ends of the support means  140 ,  150  are adjacent to each other when the vertical distance between the two decks  110 ,  120  is at a minimum L 1  and move apart from each other when the vertical distance between the two decks  110 ,  120  is at a maximum L 2 . The support means  140 ,  150  may be formed of beams having a U-shaped cross-section. 
     The guide means  160  may be positioned within the support means  140 ,  150  and/or outside the support means  140 ,  150 . Each deck  110 ,  120  is thus supported with guide means  160  on the guide rails  25  in the shaft  20 . Each deck  110 ,  120  is movable in the vertical direction S 1  along the guide rails  25 . The guide means  160  support the decks  110 ,  120  on the guide rails  25  so that only movement in the vertical direction S 1  along the guide rails  25  is possible. 
     The guide means  160  may be formed of a roller arrangement, whereby the rollers roll on the guide surfaces of the guide rails  25 . The roller arrangement may correspond to a roller arrangement used in elevator cars for guiding the elevator car on the guide rails. The guide means  160  may on the other hand be formed of glide arrangement, whereby glide means glide on the guide surfaces of the guide rails  25 . The glide arrangement may correspond to a glide arrangement used in elevator cars for guiding the elevator car on the guide rails. 
     Lifting means  130  may extend between the two decks  110 ,  120  in order to move the two decks  110 ,  120  along the guide rails  25  in relation to each other. The lifting means  130  may be formed of hydraulic actuators, e.g. telescopic cylinder means extending between the upper deck  120  and the lower deck  110 . The two decks  110  are thus movably supported in relation to each other with the hydraulic actuators. The hydraulic actuators provide only the lifting force between the two decks  110 ,  120 . Each deck  110 ,  120  is kept horizontally in position by the guide means  160 . The telescopic cylinder means  130  may comprise two telescopic cylinders  130 . The hydraulic actuators may be positioned at opposite sides of the self-climbing elevator machine room  100 . 
     Each deck  110 ,  120  may further be provided with locking means  170  on opposite vertical sides of the deck  110 ,  120 . The locking means  170  may be attached to the deck  110 ,  120  and act on the guide rails  25  and/or on guide rail fixing means. The guide rail fixing means may be formed of fish plates attaching the ends of guide rail elements together and/or of brackets attaching the guide rails to the walls of the shaft. The locking means  170  may grip the guide rails  25  and/or the fish plates  27  and/or the brackets  26 . The locking means  170  may lock the deck  110 ,  120  to the guide rails  25  in the shaft  20 . Embodiments of locking means  170  will be explained more in detail in connection with  FIGS. 5 and 6 . 
     The self-climbing elevator machine room  100  may further comprise a power source  200 . The power source  200  may provide power to the lifting means  130 , e.g. a hydraulic actuator being arranged to operate the lifting means  130 . The power source  200  may be formed of a hydraulic power unit. The hydraulic power unit may comprise an electric motor driving a hydraulic pump pumping fluid from a tank. The hydraulic power unit may supply pressurized fluid to the hydraulic actuators  130 . Electric power to the electric motor may be supplied with cables from the electric power network of the construction site. Another possibility would be to arrange batteries on the self-climbing elevator machine room  100 . 
     The self-climbing elevator machine room  100  may comprise two hydraulic power units  200 . A first hydraulic power unit may be positioned on the lower deck  110  and a second hydraulic power unit may be positioned on the upper deck  120 . The first hydraulic power unit and the second hydraulic power unit may be connected in parallel. Each of the two hydraulic power units may thus provide pressurized fluid to the hydraulic actuators in the lifting means  130 . 
     The self-climbing elevator machine room  100  may further comprise a safety brake attached to each deck  110 ,  120 . The safety brake may be formed of a continuously activated one-way brake. The safety brake allows upward movement of the deck  110 ,  120 , but prevents downward movement of the deck  110 ,  120 . Any commercial one-way safety brake may be used. 
     The self-climbing elevator machine room  100  may further comprise elevator machinery  30  and all other equipment needed in an elevator on the lower deck  110 . 
     The self-climbing elevator machine room  100  may climb stepwise along the guide rails  25  by alternatingly locking and unlocking the lower deck  110  and the upper deck  120  to the guide rails  25  with the respective locking means  170  and thereafter raising the unlocked deck  110 ,  120  with the lifting means  130 . 
     The climbing procedure may start from a situation in which both decks  110 ,  120  are locked to the guide rails  25  with the locking means  170 . 
     The first step in the climbing procedure comprises unlocking the upper deck  120 . The second step comprises lifting the upper deck  120  upwards in the shaft along the guide rails  25 . The third step comprises locking the upper deck  120  when the upper deck  120  has reached the desired destination above the lower deck  110 . The fourth step comprises unlocking the lower deck  110 . The fifth step comprises lifting the lower deck  110  upwards in the shaft  20  along the guide rails  25 . The sixth step comprises locking the lower deck  110  when the lower deck  110  has reached a desired destination below the upper deck  120 . The climbing procedure could then be repeated starting from the first step. 
     The vertical distance between the decks  110 ,  120  may vary between a minimum L 1  and a maximum L 2  during the climbing procedure. The vertical distance between the maximum and the minimum defines the maximum climbing step of the elevator machine room  100 . The maximum climbing step may reach between two consecutive floors or between several consecutive floors in the shaft. The maximum climbing step depends on the lifting means  130 . 
     The self-climbing elevator machine room  100  is in the figure shown in a situation in which the distance between the two decks  110 ,  120  is at a minimum L 1 . The upper position of the upper deck  120  is shown with broken lines, whereby the maximum distance L 2  between the two decks  110 ,  120  is achieved. 
     Installation may be done from the upper deck  120  and maybe to a limited extent also from the lower deck  110 . 
       FIG. 2  shows an axonometric view of the self-climbing elevator machine room. 
     The self-climbing elevator machine room  100  comprises two decks  110 ,  120  positioned vertically above each other. Lifting means  130  may extend between the decks  110 ,  120  for moving the two decks  110 ,  120  in the vertical direction S 1  in relation to each other. Each deck  110 ,  120  may further comprise locking means  170  for locking and unlocking the deck  110 ,  120  to the guide rails and/or to the guide rail fixing means. 
     Each deck  110 ,  120  may further comprise guide means  160  for supporting the deck  110 ,  120  movably on the guide rails  25 . The guide means  160  may be formed of roller means or glide means attached to the deck  110 ,  120 . The roller means may roll on the guide surfaces of the guide rails  25 . The glide means may glide on the guide surfaces of the guide rails  25 . 
     The self-climbing elevator machine room  100  may further comprise elevator machinery  30  and other equipment needed in an elevator. The elevator machinery may comprise a drive, a motor, a traction sheave, a machinery brake, and hoisting ropes. The figure shows further a cable drum  31  for the electrical cable of the elevator car and rope drums  32  for the hoisting ropes of the elevator. 
     The self-climbing elevator machine room  100  may further comprise two hydraulic power units  200 . A first hydraulic power unit  201  may be positioned on the lower deck  110  and a second hydraulic power unit  202  may be positioned on the upper deck  120 . The first hydraulic power unit  201  and the second hydraulic power unit  202  may be connected in parallel. Each of the two hydraulic power units  201 ,  202  may thus provide pressurized fluid to the lifting means  130  i.e. to both telescopic cylinders  130 . 
     The self-climbing elevator machine room  100  may further comprise a safety brake  500  attached to each deck  110 ,  120 . The safety brake  500  may be formed of a continuously activated one-way brake. The safety brake  500  allows upward movement of the deck  110 ,  120 , but prevents downward movement of the deck  110 ,  120 . Any commercial one-way safety brake  500  may be used. 
     The self-climbing elevator machine room  100  may also be used during the installation of the elevator in the shaft. The upper deck  120  may be used as an installation deck. The installation may be done manually and/or automatically from the upper deck  120 . Mechanics and/or robots may work on the upper deck  120 . 
       FIG. 3  shows an axonometric view of a first portion of the self-climbing elevator machine room. 
     The figure shows a portion of the lower deck  110 , the first hydraulic power unit  201  and the cable drum  31  on the first deck  110 . The cable drum  31  is needed in order to provide lengthening of the car cable as the machinery room climbs stepwise upwards in the shaft. 
     The figure shows further a safety brake  500  attached to each deck  110 ,  120 . The safety brake  500  may be formed of a continuously activated one-way brake. The safety brake  500  allows upward movement of the deck  110 ,  120 , but prevents downward movement of the deck  110 ,  120 . Any commercial one-way safety brake  500  may be used. 
     The figure shows further a further safety brake  510  attached to each deck  110 ,  120 . The further safety brake  510  may also be formed of a continuously activated one-way brake. The further safety brake  510  allows upward movement of the deck  110 ,  120 , but prevents downward movement of the deck  110 ,  120 . Any commercial one-way further safety brake  510  may be used. The further safety brake  510  could be chain blocker type safety brake. 
       FIG. 4  shows an axonometric view a second portion of the self-climbing elevator machine room. 
     The figure shows a portion of the lower deck  110  and the hoisting rope drums  32 . The hoisting rope drums  32  may be driven by a worm screw and cogged wheels as is seen in the figure. The hoisting rope drums  32  are needed in order to provided lengthening of the hoisting ropes as the machine room climbs stepwise higher in the shaft. 
       FIG. 5  shows a view of first locking means. 
     The first locking means  170  is formed of brake means  180 . The brake means  180  may comprise a frame  181  with a slit for the guide rail  25  and two wedge shaped brake shoes  182  positioned on opposite sides of the guide rail  25 . The brake shoes  182  may be movably supported from the wedge surface with rollers  183  on the frame  181 . A spring  184  may be positioned between a first end of the brake shoe  182  and the frame  181 . A second opposite end of the brake shoe  182  may be supported on a slide  185  acting in a cylinder  186 . 
     A hydraulic power unit  210  may provide power to the brake means  180 . The hydraulic unit  210  may comprise an electric motor  211 , a hydraulic pump  212  and a tank  250 . The hydraulic pump  212  pumps oil from the oil reservoir  250  to the cylinders  186  in order to move the slides  185  in the cylinders  186 . 
     Supplying pressurized fluid to the plungers  185  in the cylinders  186  will press the brake shoes  182  downwards in the figure against the force of the springs  184 . The brake shoes  182  are thus moved away from the guide surfaces of the guide rail  25 . The deck  110 ,  120  is thus free to move on the guide rails  25 . 
     Extracting pressurized fluid from the cylinders  186  will allow the brake shoes  182  to move upwards in the figure due to the force caused by the springs  184  acting on the second end of the brake shoe  182 . The brake shoes  182  are thus moved into contact with the guide surfaces of the guide rail  25 . The deck  110 ,  120  will thus become locked to the guide rails  25 . 
     The hydraulic unit  210  may be provided only for the brake means  180 . Another possibility is to have a common main hydraulic unit on the self-climbing elevator machine room  100  for all equipment needing hydraulic power on the self-climbing elevator machine room  100 . Hydraulic valves may be used to connect the different equipment to the common main hydraulic power unit. 
     The brake means  180  may as an alternative be operated electromechanically. An electromechanical device may be used to press the brake shoes  182  against the force of the springs  184 . Deactivation of the electromechanical device will activate the brake shoes  182  against the guide rails  25 . 
       FIG. 6  shows a view of second locking means. 
     The second locking means  170  is formed of anchoring means  190 . The anchoring means  190  may comprise a frame  191  supported on the deck  110 ,  120  and two claws  192  positioned on opposite sides of the guide rail  25 . The claws  192  may be supported via a first articulated joint J 1  on the frame  191 . An actuator may be attached to the claws  192  on an opposite side of the first articulated joint J 1  (not shown in the figure). The actuator may rotate the claws  192  around the first articulated joint J 1  between a locked position in which the claws  192  are seated on an upper support surfaces  27 A of the fish plates  27  and an unlocked position in which the claws are rotated in a clockwise direction and thereby removed from contact with the fish plate  27 . 
     The actuator may be formed of a hydraulic cylinder or of an electromechanical device. The claws  192  could be operated by an electric motor or by one or more electromechanical devices. 
     The deck  110 ,  120  becomes supported on the fish plate  27  in the locked position of the anchoring means  190 . The support on the fish plate  27  eliminates downward movement of the deck  110 ,  120 . The deck  110 ,  120  is free to move on the guide rails  25  in the unlocked position of the anchoring means  190 . 
     The fish plates  27  are normally positioned in the joint between two consecutive guide rail elements. Additional fish plates  27  could be positioned along the length of the guide rail elements. The guide rail element could be provided with intermediate fish plates  27  attached to the guide rail elements already before the installation of the guide rail elements. A fish plate  27  could e.g. be positioned in the middle of a 5 m long guide rail element. The intermediate fish plates  27  could be left on the guide rails permanently after the installation. Another possibility would be to remove the intermediate fish plates as the installation proceeds upwards. 
     The fish plate  27  may be wider than the guide rail  25  so that the upper surface of the fish plate  27  forms an upper support surface  27 A for the claw  192  on each side of the guide rail  25 . The construction of the fish plates  27  may thus be adapted to work as support points for the claws  192  in the anchoring means  190 . 
     The fish plate  27  is an example of a connection element that may be used to connect the ends of consecutive guide rail elements. 
     A similar anchoring means  190  could be used to lock the deck  110 ,  120  to the brackets  26  attaching the guide rails  25  to the walls  21  in the shaft  20 . The claws  192  could then interact with brackets  26 . 
       FIG. 7  shows a side view of a second lifting means. 
     The second lifting means could be formed as an articulated jack  600 . A middle portion of two support arms  610 ,  620  could be connected via an articulated joint J 31 . The upper end of each support arm  610 ,  620  may be supported via articulated joint J 21 , J 22  on the upper deck  120 . The lower end of each support arm  610 ,  620  may be supported via an articulated joint J 11 , J 12  on the lower deck  110 . Each of the articulated joints J 11 , J 12  at the lower deck  110  and each of the articulated joints J 21 , J 22  at the upper deck  120  should be arranged so that movement of the ends of the support arms  610 ,  620  in the horizontal direction is allowed, but movement in the vertical direction is prevented. 
     An actuator  630  may be provided on the lower deck  110 . The actuator may be connected to a rod  640  passing in a horizontal direction along the lower deck  110 . The rod  640  may be formed as a worm. 
     The lower end of the first support arm  610  could be attached via a shaft  640  to an actuator  630 . The lower end of the first support arm  610  may be provided with articulated joint cooperating with the worm screw  640 . The worm screw  640  may be attached via joint parts to the lower end portions of the support arms  610 ,  620 . The outer ends of the worm screw  640  may be supported on the lower deck  110 . 
     Rotation of the actuator  630  in a first direction will move the lower ends of the support arms  610 ,  620  towards each other, whereby the lower deck  110  and the upper deck  120  is moved in a direction away from each other. Rotation of the actuator  630  in a second opposite direction will move the lower ends of the support arms  610 ,  620  away from each other, whereby the lower deck  110  and the upper deck  120  is moved in a direction towards each other. The lower deck  110  and the upper deck  120  may thus be lifted alternatingly upwards with the actuator  630 . 
     The lower deck  110  may be locked to the guide rails, whereby the unlocked upper deck  120  may be lifted by rotating the actuator  630  in the first direction. The upper deck  120  may thereafter be locked to the guide rails, whereby the lower deck  110  may be lifted by rotating the actuator  630  in the second direction. 
     The actuator  630  may be formed of a motor, e.g. an electric motor rotating the worm screw  640 . A pair of articulated jacks  600  may be used i.e. one articulated jack  600  may be positioned at each side edge of the decks  110 ,  120 . 
     The articulated jack  600  could as an alternative be operated by a hydraulic cylinder-piston apparatus. The cylinder-piston apparatus could extend between the lower deck  110  and an upper portion of either support arm  610 ,  620 . The articulated jack  600  could also comprise several layers of crosswise running support arms stacked upon each other. 
       FIG. 8  shows a first side view of a third lifting means,  FIG. 9  shows a second side view of the third lifting means, and  FIG. 10  shows a third side view of the third lifting means. 
     The third lifting means  700  could be realized with ropes and pulleys. Two parallel support structures  710 ,  720  may extend between the first deck  110  and the second deck  120 . The two support structures  710 ,  720  may be positioned at a horizontal distance from each other. Each of the support structures  710 ,  720  may comprise an inner support bar  711 ,  721  and an outer support bar  712 ,  722 . The inner support bar  711 ,  721  is positioned inside the outer support bar  712 ,  722 . The inner support bar  711 ,  721  may be locked to the outer support bar  712 ,  722  with a form lock so that the inner support bar  711 ,  721  may move in the longitudinal direction in relation to the outer support bar  712 ,  722 . The lower end of the outer support bar  712 ,  722  may be attached to the lower deck  110  and the upper end of the inner support bar  711 ,  721  may be attached to the upper deck  120 . 
     A first shaft  731  may extend in a horizontal direction between the lower end portions of the inner support bars  711 ,  721 . Each end of the first shaft  731  may be attached to a lower end of a respective inner support bar  711 ,  721 . A second shaft  732  may extend in a horizontal direction between the lower end portions of the outer support bars  712 ,  722 . Each end of the second shaft  732  may be attached to a lower end of a respective outer support bar  712 ,  722 . The first shaft  731  and the second shaft  732  may be positioned on opposite sides of the two support structures  710 ,  720 . A third shaft  733  may extend between the upper end portions of the outer support bars  712 ,  722 . Each end of the third shaft  733  may be attached to an upper end of a respective outer support bar  712 ,  722 . 
     A first pulley  741  may be positioned between the two support structures  710 ,  720 . The first pulley  741  may be rotatably supported on the third shaft  733 . The first pulley  741  is thus stationary in relation to the outer support bars  712 ,  722 . A second pulley  742  may be positioned between the two support structures  710 ,  720 . The second pulley  742  may be rotatably supported on the second shaft  732 . The second pulley  742  is thus stationary in relation the outer support bars  712 ,  722 . 
     A first end of a rope  750  may be fixed in a first fixing point P 1  to the first shaft  731 . The rope  750  may pass from the first fixing point P 1  upwards to the first pulley  741 . The rope  750  may then turn around the first pulley  741  and pass downwards to the second pulley  742 . The rope  750  may then turn around the second pulley  742  and pass upwards through a lifting apparatus  760  supported on the lower deck  110 . A second end of the rope  750  may be free. 
     The lifting apparatus  760  may be a man riding hoist. The lifting apparatus  760  may comprise traction rolls positioned on opposite sides of the rope  750 . The traction rolls may be driven by one or more motors, e.g. electric motors. Rotation of the traction rolls in a first direction will pull the rope  750  upwards through the lifting apparatus  760 . Rotation of the traction rolls in a second opposite direction will move the rope  710  in a second opposite direction downwards through the lifting apparatus  760 . The traction rolls will thus control the movement of the rope  750  through the lifting apparatus  760 . 
     The decks  110 ,  120  are shown in a position in which the vertical distance between the lower deck  110  and the upper deck  120  is at a minimum. 
     The lower deck  110  may first be locked to the guide rails, whereby the upper deck  120  is unlocked. The lifting apparatus  730  may now start to pull the rope  710  in the first direction upwards through the lifting apparatus  760 . The first end of the rope  750  is attached to the first shaft  731 , which is attached to the lower ends of the inner support bars  711 ,  721 . The inner support bars  711 ,  721  will thus start to move upwards, whereby also the upper deck  120  starts to move upwards in relation to the stationary lower deck  110 . The vertical distance between the lower deck  110  and the upper deck  120  will be at a maximum when the first shaft  731  is at a distance below the first pulley  741 . The first shaft  731  may be raised to a position below the outer circumference of the first pulley  741 . There should be overlapping between the inner support bars  711 ,  721  and the outer support bars  712 ,  722  also in the position in which the distance between the decks  110 ,  120  is at a maximum. 
     The upper deck  120  may then be locked to the guide rails, whereby the lower deck  110  is unlocked. The lifting apparatus may now start to pull the rope  750  in a second opposite direction downwards through the lifting apparatus  760 . The lower deck  110  will start to move upwards, whereby the outer support bars  712 ,  722  move upwards along the inner support bars  711 ,  721 . The lower deck  110  moves upwards until the first support point P 1  is again in the position near the lower deck  110 . We thus end up in the situation shown in the figure where the vertical distance between the decks  110 ,  120  is at a minimum. 
     The shafts  731 ,  732 ,  733  may be stationary and the pulleys  741 ,  742  may be rotatably attached to the shafts  732 ,  733 . 
       FIG. 11  shows a side view of a fourth lifting means,  FIG. 12  shows an enlargement of a lower portion of the lifting means shown in FIG.  11  and  FIG. 13  shows an enlargement of an upper portion of the lifting means shown in  FIG. 11 . 
     The lifting means  800  is on the left hand side of  FIG. 11  shown in an expanded state and on the right hand side of  FIG. 11  in a contracted state. 
     The lifting means  800  is formed of a support structure  805  comprising three support bars  810 ,  820 ,  830  that are movably supported on each other. The third support bar  830  may be supported with a first form locking within the second support bar  820 . The second support bar  820  may be supported with a second form locking within the first support bar  810 . The third support bar  830  may move in the longitudinal direction in relation to the second support bar  820 . The second support bar  820  may move in the longitudinal direction in relation to the first support bar  810 . The form locking of the support bars  810 ,  820 ,  830  is shown in  FIG. 13 . 
     The movement of the support bars  810 ,  820 ,  830  in relation to each other is done with cogged belts or chains  851 ,  852  and cogwheels  841 A,  841 B,  842 A,  842 B,  843 A,  843 B,  844 A,  844 B,  845 A,  845 B. The cogged belts or chains  851 ,  852  may be driven by an actuator  860 . The actuator  860  may be a motor, e.g. an electric motor. 
     A first cogged belt or chain  851  may be positioned on a first side of the support structure  805  and a second cogged belt or chain  852  may be positioned on a second opposite side of the support structure  805 . 
     The first cogged belt or chain  851  may pass in a closed loop over cogwheels  841 A,  842 A,  843 A,  844 A and  845 A on a first side of the support structure  805 . The second cogged belt or chain  852  may pass in a closed loop over cogwheels  841 B,  842 B,  843 B,  844 B and  845 B on a second side of the support structure  805 . The cogwheels on opposite sides of the support structure  805  may be arranged in pairs. The cogwheels in each pair of cogwheels being positioned opposite each other so that the centre axis of the shafts of the cogwheels coincide. Each cogwheel may be rotatably supported on a shaft, whereby the shaft is stationary and attached to the support structure  805 . The other possibility is that each cogwheel is fixed to the shaft and the shaft is rotatably attached to the support structure  805 . 
     The first cogwheel  841 A on the first side of the support structure  805  and the first cogwheel  841 B on the second opposite side of the support structure  805  may be connected to each other with a first shaft  831 . The first shaft  831  may further be connected to an actuator  860 . The actuator  860  may be a motor, e.g. an electric motor. The motor  860  may drive the two cogged belts or chains  851 ,  852  in synchronism. The first shaft  831  may pass through a lower end portion  811  of the first support bar  810 . The first shaft  831  may be rotatably supported on the lower end portion  811  of the first support bar  810 . Said lower end portion  811  of the first support bar  810  may be attached to the lower deck  110 . The upper end of the third support bar  830  may be attached to the upper deck  120 . 
     The first pair of cogwheels  841 A,  841 B are thus stationary in relation to the first support bar  810 . The second pair of cogwheels  842 A,  842 B are supported on the upper end of the second support bar  820 . The third pair of cogwheels  843 A,  843 B are supported on the lower end of the second support bar  820 . The fourth pair of cogwheels  844 A,  844 B are supported on the upper end of the first support bar  810 . The fifth pair of cogwheels  845 A,  845 B are supported on the lower end  811  of the first support bar  810 . The fifth pair of cogwheels  845 A,  845 B are thus stationary. A lower end of the third support bar  830  is further attached via a second shaft  832  to both cogged belts or chains  851 ,  852 . 
     When the motor  860  is rotated in a first clockwise direction, then the second support bar  820  and the third support bar  830  will move upwards as shown on the left hand in  FIG. 11 . 
     When the motor  860  is rotated in a second, counter clockwise direction, then the second support bar  820  and the third support bar  830  will move downwards and return to the position shown on the right hand in  FIG. 11 . 
     This third lifting means  800  may be modified so that two parallel support structures  805  positioned at a distance from each other e.g. at opposite edges of the decks  110 ,  120  are used. Each support structure  805  may comprise three support bars  810 ,  820 ,  830 . The two support structures  805  could be connected to each other with shafts or profiles. Corresponding cogwheels  841 A,  842 A,  843 A,  844 A,  845 A could be provided on a middle portion of the shafts or profiles. The drive could then be realized with one cogged belt or chain. 
     The lifting means  130  could as a further alternative be realized with a screw mechanism operated by an actuator. The actuator could be a motor, e.g. an electric motor. Gear racks, pinions and worm screws could be used in the screw mechanism. 
     The decks  110 ,  120  may in each embodiment of the invention comprise guide means  160  for supporting the deck  110 ,  120  movably on the guide rails  25  and locking means  170  for locking and unlocking the deck  110 ,  120  to the guide rails  25  and/or to guide rail fixing means  26 ,  27 . 
     The at least one power source  200  may be formed of a hydraulic power unit comprising an electric motor, a hydraulic pump and a tank. The at least one power source  200  may on the other hand be formed of one or more motors providing power via a rotating shaft, e.g. a hydraulic motor or an electric motor. The one or more motors may provide power to the lifting apparatus  130 . 
     The use of the invention is not limited to any specific elevator type. The invention can be used in connection with any type of elevator e.g. also in elevators lacking a machine room and/or a counterweight. The counterweight could be positioned on the back wall of the shaft or on either side wall of the shaft or on both side walls of the shaft. 
     It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.