Abstract:
The battery counterweighted elevator is adapted for rack and pinion or cable traction elevators. The elevator uses electrical power from a solar cell array to charge or recharge storage batteries, which, in turn, provide the electrical power to drive the elevator. The storage batteries serve as counterweights for at least a substantial portion of the weight of the elevator car, and travel up and down opposite the car. A traveling cable connects the elevator car with the batteries in the counterweight in the case of the rack and pinion elevator, with the cable providing power to the drive motor situated with the car and also providing control of the system from the car. The cable traction elevator has a traveling control cable extending to a fixed junction box, with power supplied from the batteries to the junction box and thence to the fixed motor at the top of the hoistway.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to elevator systems, and particularly to a battery counterweighted elevator using the rack and pinion or cable traction drive principle of operation, wherein a counterweight is provided substantially by electrical storage batteries used to power the elevator. 
         [0003]    2. Description of the Related Art 
         [0004]    Elevators generally use one of three operating principles, i.e., hydraulic, cable traction, or rack and pinion operation. Hydraulic elevators are limited to a relatively few stories of lift height, but cable traction and particularly rack and pinion systems are relatively unlimited as to the height of the building structures in which they may be installed. While most people are more familiar with elevator systems installed in taller office structures and the like, elevators, and particularly rack and pinion elevators, are often installed in tall industrial structures to facilitate maintenance and repair of such structures and the equipment therein and thereon. 
         [0005]    An example of such is found in large wind generators, where the tower may extend to well over one hundred feet above the surface in order to provide clearance for the large diameter wind blades. Remotely located radio and television broadcast towers, weather and aviation radar towers, and similar structures are also excellent candidates for such industrial elevators. Obviously, the taller the structure, the more power is required to drive the elevator to the top. While it is possible to recover some of that power through regenerative braking on the descent, it is not possible to recover all of the power expended in lifting the elevator. The power requirement may be minimized by using counterweights approximately equal to the empty weight of the elevator car and its equipment, but conventionally most counterweight systems comprise dead weight using heavy metal ballast, concrete, or the like. 
         [0006]    While most taller structures have (or supply, in the case of wind generators) electrical power, the electrical power is generally intended to operate equipment or (in the case of wind generators) to be delivered commercially to other users. Using the electrical power intended for other use to drive an elevator is generally regarded as inefficient, but oftentimes there is no other suitable source of elevator power available. While solar power generation has been considered for powering remotely situated electrical devices, some means of storing the generated solar power until it is needed is required for such systems. 
         [0007]    Thus, a battery counterweighted elevator solving the aforementioned problems is desired. 
       SUMMARY OF THE INVENTION 
       [0008]    The battery counterweighted elevator may utilize either the rack and pinion or cable traction principle of operation. Either elevator type incorporates a cable-suspended counterweight assembly to reduce power requirements. Electrical power for powering the elevator is preferably provided primarily by a solar power source, although electrical power from some other external source, e.g., conventional electrical power grid, may also be provided to supplement the solar power source. Regardless of the source, the electrical power is used to charge (or recharge) a number of electrical storage batteries. The batteries also serve as the counterweight for the elevator car and its attached equipment. 
         [0009]    The rack and pinion elevator incorporates at least one drive motor, reduction gearing, and safety systems and controls within or on the elevator car or cab. The motor drives a pinion that engages the rack that extends along the height of the elevator hoistway. A traveling cable extends from a fixed electrical junction box adjacent to the elevator hoistway to the batteries in the counterweight to provide electrical power for recharging the batteries. Electrical power is provided to the junction box primarily by solar power or, alternatively, by supplemental power from a conventional electrical power grid. A power and communications traveling cable extends from the junction box to the elevator car to provide power to the drive motor and control of that power from the cab. 
         [0010]    The motive power for the cable traction elevator is disposed at the top of the elevator hoistway, and drives a pulley or sheave system controlling a cable connected to the top of the elevator car. Since the drive motor is fixed at the top of the hoistway or tower, the power cable from the fixed junction box is also fixed and does not travel as it does in the case of the rack and pinion elevator. However, the traveling counterweight with its batteries is connected to the junction box via a traveling power cable, which may incorporate a line for charging the batteries as well. Another traveling cable extends from the elevator car to the junction box to provide control of the elevator from within the car and to provide communications from the car. The junction box receives primary power for recharging the batteries from a solar power source, and alternative power from a conventional electric power grid or other suitable source if the solar power is insufficient. 
         [0011]    These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a schematic elevation view of a first embodiment of a battery counterweighted elevator according to the present invention, showing the counterweight in a rack and pinion elevator system. 
           [0013]      FIG. 2  is a schematic elevation view of a second embodiment of a battery counterweighted elevator according to the present invention, showing the counterweight in a cable traction elevator system. 
       
    
    
       [0014]    Similar reference characters denote corresponding features consistently throughout the attached drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]    The battery counterweighted elevator comprises different embodiments of an electrically powered elevator using electric storage batteries as the power supply. The batteries are recharged from another electrical source, as needed. The batteries are installed in a counterweight used to offset at least some of the weight of the elevator car and its associated equipment. The battery counterweighted elevator system may be applied to either a rack and pinion or a cable traction elevator operating system. 
         [0016]      FIG. 1  of the drawings provides a schematic illustration of a rack and pinion type elevator system  10  incorporating the battery counterweight. The rack and pinion elevator system  10  has a hoistway  12  with an upper end  14  and opposite lower end  16 . The hoistway includes a linear toothed rack  18  extending from the upper end  14  to the lower end  16 . An elevator car  20  is installed in the hoistway  12  and travels up and down the hoistway  12 , as is conventional in such rack and pinion elevator systems. The elevator car  20  has at least one elevator drive motor  22  installed therewith, e.g., atop the car  20 , as shown in  FIG. 1 , with the drive motor  22  driving a pinion that engages the rack  18  to drive the elevator up the rack and hoistway  12  when commanded. Such rack and pinion systems are conventional, and need not be shown and described in further detail herein. 
         [0017]    A counterweight  24  is suspended in the hoistway  12  by a cable  26 . The counterweight cable  26  extends from the top of the elevator car  20  upwardly to pass over a passive pulley assembly  28  at the upper end  14  of the hoistway  12 , and thence downwardly to the counterweight  24 . The counterweight  24  thus travels in a direction opposite the direction of travel of the elevator car  20 , e.g., the counterweight travels downwardly when the car is moving upwardly. The counterweight  24  carries sufficient weight to balance or offset at least a substantial portion of the weight of the empty elevator car  20 , i.e., at least more than half of the weight of the empty car  20 . The weight of the counterweight  24  may be adjusted to approach one hundred percent of the empty weight of the car  20 , if desired. 
         [0018]    A substantial portion of the weight of the counterweight  24  comprises one or more (preferably several) electric storage batteries  30 , disposed on or within the counterweight  24 . A traveling power cable  32  extends between the elevator car  20  and the counterweight  24 , the cable  32  hanging in a catenary arc below the car  20  and counterweight  24 . The power cable  32  provides electrical power from the storage batteries  30  within the counterweight  24  to the elevator drive motor  22  installed in or on the car  20 . 
         [0019]    Another traveling cable may be physically attached or linked to the power cable  32 , or may be suspended separately from the power cable  32 , if desired. The additional traveling cable comprises a control and communications cable  34  that extends between the elevator car  20  and the counterweight  24 . A control panel within the elevator car  20  is used to transmit signals through or along this control and communications cable  34  to control the power output of the batteries  30  within or on the counterweight  24 , thus controlling movement of the elevator car  20 . 
         [0020]    The counterweight  24  preferably also contains a battery charger  36 . The charger  36  could be located elsewhere, but as its weight is substantial due to the output amperage required, it is preferably located with the counterweight  24  in order to provide additional weight therein. The charger  36  receives electrical power from a junction box  38  immovably affixed within or adjacent to the hoistway  12 , with a traveling battery charger power cable  40  extending between the mobile counterweight  24  and the stationary electrical junction box  38 . 
         [0021]    The junction box  38  receives electrical power from an external source via a fixed cable  42 , which provides electrical power to the battery charger  36  and thence to the batteries  30  to keep them charged. The battery counterweighted elevator  10  is particularly well suited for installations in or on relatively remote towers and the like. Such installations may have limited electrical power available. Accordingly, the junction box  38  preferably receives electrical power from a solar panel array  44 . Solar panel arrays require significant area to put out adequate electrical power, but the battery counterweighted elevator is anticipated to be operated infrequently. Thus, the batteries  30  may be recharged slowly over a relatively long period of time before the next elevator operation occurs. However, the system may be connected into the conventional electric power supply grid  46  if it is anticipated that additional electrical power may be required for heavy usage of the elevator  10  or for other reasons. 
         [0022]    Additional subsystems providing further efficiency and safety may be included in the system, as desired. For example, some of the energy expended in raising the elevator car  20  may be recovered when the car descends if a motor/generator is used as the elevator drive motor  22 . Such motor/generators are conventional and well known for use in systems where a reverse electromagnetic force occurs when the motor is driven, rather than driving the system, as when elevator is descending. The electrical energy generated under such conditions may be delivered to the battery charger  36  via the traveling power cable  32 , to deliver power by regenerative braking. 
         [0023]    The battery counterweighted elevator system  10  also preferably includes additional safety subsystems, e.g., an overspeed safety brake and speed governor  48 . Such systems are conventional, and accordingly need not be described in further detail herein. 
         [0024]      FIG. 2  of the drawings is a schematic elevation view of a cable traction elevator system  110  incorporating a battery counterweight apparatus. The cable traction elevator system  110  has a hoistway  112  with an upper end  114  and opposite lower end  116 . An elevator car  120  is installed in the hoistway  112  and travels up and down the hoistway  112 , as is conventional in such cable traction elevator systems. The elevator car  120  is suspended by a lift cable  126  that extends from the top of the elevator car  120  upwardly to pass over or through a drive pulley and sheave system  128  at the upper end  114  of the hoistway  112 . The drive pulley and sheave system  128  is powered by an elevator drive motor  122  installed therewith. The lift cable  126  continues over and through the drive pulley and sheave system  128  and continues downwardly, where it attaches to a counterweight  124 . The counterweight  124  thus travels in a direction opposite the direction of travel of the elevator car  120 , e.g., the counterweight travels downwardly when the car is moving upwardly. The counterweight  124  carries sufficient weight to balance or offset at least a substantial portion of the weight of the empty elevator car  120 , i.e., at least more than half of the weight of the empty car  120 . The weight of the counterweight  124  may be adjusted to approach one hundred percent of the empty weight of the car  120 , if desired. 
         [0025]    A substantial portion of the weight of the counterweight  124  comprises one or more (preferably several) electric storage batteries  130 , disposed on or within the counterweight  124 . A traveling power cable  132   a  extends from the counterweight  124  to a junction box  138  immovably affixed within or adjacent to the hoistway  112 . The cable  132   a  hangs in a catenary arc below the junction box  138  and counterweight  124 . A fixed or stationary continuation  132   b  of this cable continues from the junction box  138  to the elevator drive motor  122  located at the upper end  114  of the hoistway. The power cable  132   a  and  132   b  provides electrical power from the storage batteries  130  within the counterweight  124  to the elevator drive motor  122  installed at the upper end  114  of the hoistway  112  to drive the drive pulley and sheave system  128 , thereby lifting the elevator car  120 . 
         [0026]    A control and communications traveling cable  134  extends between the elevator car  120  and the electrical junction box  138 . A battery charger power and communications traveling cable  140  extends between the junction box  138  and the counterweight  124 . A control panel within the elevator car  120  is used to transmit signals through or along this control and communications cable  134  to the junction box  138  and thence through the charger power and communications cable  140  to the counterweight  124  to control the power output of the batteries  130  within or on the counterweight  124 , thus controlling movement of the elevator car  120 . The traveling charger power and communications cable  140  may be physically attached or linked to the traveling portion of the power cable  132   a , or may be suspended separately from the power cable  132   a  traveling portion, if desired. 
         [0027]    The counterweight  124  preferably also contains a battery charger  136 . The charger  136  could be located elsewhere, but as its weight is substantial due to the output amperage required, it is preferably located with the counterweight  124  in order to provide additional weight therein. The charger  136  receives electrical power from the junction box  38  via the traveling battery charger power cable  140  extending between the mobile counterweight  124  and the stationary electrical junction box  138 . 
         [0028]    The junction box  138  receives electrical power from an external source via a fixed cable  142 , to provide electrical power to the battery charger  136  and thence to the batteries  130  to keep them charged. The battery counterweighted cable traction elevator  110  is particularly well suited for installations in or on relatively remote towers and the like. Such installations may have limited electrical power available. Accordingly, the junction box  138  preferably receives electrical power from a solar panel array  144 . Solar panel arrays require significant area to put out adequate electrical power, but the battery counterweighted elevator is anticipated to be operated infrequently, thus allowing the batteries  130  to be recharged slowly over a relatively long period of time before the next elevator operation occurs. However, the system may be connected into a conventional electric power supply grid  146  if it is anticipated that additional electrical power may be required for heavy usage of the elevator or for other reasons. 
         [0029]    Additional subsystems providing further efficiency and safety may be included in the system, as desired. For example, some of the energy expended in raising the elevator car  120  may be recovered when the car descends if a motor/generator is used as the elevator drive motor  122 . Such motor/generators are conventional and well known for use in systems where a reverse electromagnetic force occurs when the motor is driven, rather than driving the system, as when the elevator is descending. The electrical energy generated under such conditions may be delivered to the battery charger  136  via the fixed and traveling power cables  132   a  and  132   b  to recharge the battery charger  136  by regenerative braking. 
         [0030]    The battery counterweighted cable traction elevator system  110  also preferably includes additional safety subsystems to prevent excessive speed or free fall of the elevator car  120  in the event of lift cable breakage or other catastrophic failure of the system. Such systems are conventional, and accordingly need not be described in further detail herein. 
         [0031]    It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.