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FIELD OF THE INVENTION 
       [0001]    The invention relates to structures, mechanisms, methods and systems used for storing and retrieving articles, such as passenger cars. 
       BACKGROUND OF THE INVENTION 
       [0002]    In many real estate developments, the space required to park passenger vehicles is a large part of the cost. It is desirable to minimize this cost. An automated parking structure in which vehicles are parked in close proximity without the space needed to open and close doors or for people to enter or exit the vehicles can increase the number of vehicles parked in a given volume or surface footprint. Such structures may use vehicle moving equipment to pick and place the vehicles into parking slots. These structures usually require that various parts of the parking structure, including the transfer room(s) through which the vehicles enter and leave the parking structure, have fixed elements that, in these designs, are required to interact with some form of vehicle moving equipment. For example, some automated parking structures require that the transfer room have a floor with one or more open slots through which parts of a vehicle transfer apparatus can pass. In these systems, the vehicle moving equipment is thicker than the space allowed by the vehicle ground clearance. Slots are therefore required to enable the prior vehicle moving equipment to pass under the vehicle body so that it may engage the vehicle without damaging its bodywork. Similar slots are then required in the parking storage space to allow the vehicle to be placed there by the prior vehicle moving equipment. These slots, grooves and similar accommodations add cost and complexity to the parking structure. Further, they make it difficult to change the size of a parking space as the slots, grooves or other accommodations are often integral with the fixed floor and can not be moved or easily modified. Finally, the addition of slots, grooves and similar accommodations may increase the thickness of each parking floor, thereby potentially reducing the number of parking floors possible in a structure of a given height. However, as vehicle demographics change, it may be desirable for a garage operator to be able to either widen or narrow the parking spaces to maximize revenue at that facility or adjust to a change in the size mix of vehicles using the facility. 
         [0003]    An additional consideration in the design of an automated parking structure is the amount of time required to place or retrieve a vehicle, known as vehicle throughput. The prior art generally carries out various steps in the parking process in sequence, for example by waiting until the apparatus has moved under the vehicle to adjust the vehicle moving equipment to accommodate the wheelbase of the vehicle to be transferred. This is a sequential operation and thus requires time for the equipment to first move under the vehicle, locate a first set of tires, adjust to that location, and then determine the position of the second set of tires and adjust to that position. The sequential nature of this operation is thus one of the factors directly affecting the throughput of the garage. A solution that eliminates or reduces the time lost adjusting the equipment to the particular vehicle to be moved has not been demonstrated in the prior art. However, measuring the wheelbase of an incoming vehicle prior to it being engaged by the vehicle transfer apparatus of the present invention, and then preadjusting the vehicle transfer apparatus while it is approaching the vehicle, will eliminate loss of time. This will improve the operation of the parking facility by lessening the time required to adjust the vehicle transfer apparatus to the particular wheelbase of the vehicle to be moved. 
         [0004]    Another consideration in the design of an automated parking structure is the desired orientation of vehicles as they are retrieved from the parking structure. That is, the designer must consider whether, when the vehicle is returned to its driver, it is to be oriented so that it can be driven out of the transfer room in a forward direction, or if it is acceptable to return the vehicle so that it must be driven out in reverse. In the present invention, this problem is addressed by incorporating a turntable and a bi-directional dolly. The turntable is operable to rotate the vehicle at least  180  degrees, while the bi-directional dolly enables the vehicle to be retrieved or deployed from either side of the vehicle transfer apparatus such that the vehicle can be oriented in the transfer room ready for an easy exit. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention as disclosed herein is an improved vehicle parking structure. The vehicle parking structure provides for the automated storage and retrieval of vehicles in response to user inputs. In one aspect, the vehicle parking structure comprises one or more transfer rooms in which a vehicle operator may deposit and later retrieve a vehicle, a plurality of parking spaces of either fixed or variable dimensions, and one or more vehicle transporters used to move vehicles from the one or more transfer rooms to the plurality of parking spaces. The one or more vehicle transporters are in turn each preferably comprised of one or more vertical stabilizers, one or more tractors, one or more lifts, a lifting platform, and a dolly. The vehicle transporters move the lifting platform and dolly so that the dolly may be positioned to access a vehicle located in a transfer room or parking space. The lifting platform in turn carries the dolly and, in a preferred embodiment, also carries a rotary table suitable for rotating the dolly and a tilting mechanism. 
         [0006]    The dolly of the present invention provides an apparatus for engaging and moving a vehicle such that the vehicle may be lifted and lowered vertically so that the vehicle tires may be disengaged from the parking space or transfer room floor, and moved linearly on and off the platform. In one or more alternate embodiments, the present invention may also provide the functions of tilting either the dolly and/or lifting platform relative to a horizontal axis, rotating around a vertical axis, and/or skewing relative to a vertical axis. Furthermore, a combination of the described motions may be carried out simultaneously. 
         [0007]    In another aspect, the vehicle parking structure may be configured in a number of manners with regard to the orientation of the parking spaces, transfer rooms and vehicle transporters. In particular, in an embodiment in which a vehicle transporter has a direction of horizontal travel, the vehicle parking structure may be constructed with parking spaces arrayed on one or more sides of the vehicle transporter perpendicular to the direction of horizontal travel. By providing a bi-directional dolly which can load and offload vehicles on one or more sides of the vehicle transporter, the vehicle parking structure of the present invention offers operators greater flexibility in the design and implementation of the structure. 
         [0008]    In a preferred embodiment of the present invention having at least two vehicle transporters, the vehicle transporters are designed such that the vehicle transporters operate independently and each is able to reach and service each of the vehicle transfer rooms and each of the plurality of parking spaces. This offers an advantage in that, if one of the vehicle transporters ceases to function, either through breakdown or for scheduled maintenance, at least one other vehicle transporter will remain able to place and/or retrieve vehicles to or from any parking space in the vehicle parking structure. Of course, an arrangement wherein an out-of-service vehicle transporter blocks at least one vehicle transfer room and/or some number of parking spaces would not deviate from the scope of the present invention. 
         [0009]    In another aspect of the present invention, the vertical stabilizer is a substantially rigid mast or masts to which the lifting platform may be operably connected, or, alternatively, the vertical stabilizer may constitute one or more generally flexible guides such as cables. Whether the vertical stabilizer is substantially rigid or generally flexible, in the apparatus of the present invention, the vertical stabilizer may be expandable such that if additional vertical levels of parking spaces are added, the vertical stabilizer may expand to accommodate the additional vertical lift necessary. 
         [0010]    In another aspect of the present invention, the vertical stabilizer may engage the vehicle parking structure in a number of manners. For example, the vertical stabilizer may be constructed such that it hangs from the parking structure. In this embodiment, the weight of the vertical stabilizer, the lifting platform, the vehicle and any additional elements is suspended from the structure. Alternatively, the vertical stabilizer may be supported by the floor of the structure, or otherwise support its own weight along with the weight of the lifting platform, the vehicle and additional elements. In this later embodiment, the vertical stabilizer must be better able to withstand the compressive forces associated with supporting the given weights. 
         [0011]    Furthermore, in various alternate embodiments, tractors, which are operably connected with the one or more vertical stabilizers and/or a framework employed to interconnect a plurality of vertical stabilizers and which provide motion to the one or more vehicle transporters, may take any of a number of forms. For example, the tractors may constitute a motorized wheel assembly fixedly mounted to either the top end, bottom end, or both ends of the vertical stabilizer. In an embodiment in which multiple tractors are employed on a single vehicle transporter, it is preferred to incorporate a synchronizer such as a shaft, chain, belt or electronic controllers to ensure that the multiple tractors remain synchronized to reduce the possibility of inducing bending stresses in the one or more vertical stabilizers caused by unequal movements of the multiple tractors. Alternatively, in an embodiment which does not utilize a synchronizer to coordinate the tractors, a relatively more rigid connection between the one or more vertical stabilizers and the tractors may be required. In yet another embodiment, the tractors may not be fixedly mounted to the one or more vehicle transporters, but may take the form of fixed motors mounted within the vehicle parking structure and operably engaged with the vehicle transporters through a system of cables, chains or the like. In another aspect, a series of tracks, rails or guides may be provided within the vehicle parking structure on or in which the vehicle transporter may travel to reduce the likelihood of the vehicle transporter traveling in a non-linear fashion, or of traveling in direction which is not substantially perpendicular to the longer dimension of the individual parking spaces which comprise the plurality of parking spaces. 
         [0012]    In another embodiment, one or more winches are provided to raise and lower the lifting platform, with or without the vehicle, in the vertical direction, such as to transfer the lifting platform, with or without the vehicle, from one of the vehicle transfer rooms to one of the plurality of parking spaces. The winches may be mounted in any number of locations, such as integral with the lifting platform, or mounted to one of the tractors, depending on where the lifting loads are to be borne. It should be noted that although the term winch is used to describe the lifting apparatus, this term should not be limited to the conventional cable-over-drum arrangement. Any mechanism for providing lift to the lifting platform should be considered within the scope of the term winch. 
         [0013]    In yet another aspect of the present invention, electrical power may be provided to the vehicle transporters via a series of cables. Alternatively, to eliminate the problems associated with the use of cables, such as the cables becoming tangled with the vehicle transporters or any other structure or other cabling in the vehicle parking structure, a power rail system comprising at least one power rail may be employed. The use of a power rail system provides an additional benefit in that, by terminating the power rail at a location beyond which it is not desirable to allow the vehicle transporters to travel, it is possible to prevent the vehicle transporters from over-traveling and colliding with either the vehicle parking structure itself, or with another vehicle transporter. 
         [0014]    In yet another aspect of the present invention, a dolly may be provided to engage a vehicle and to move it between one of the vehicle transfer rooms and the lifting platform, and between the lifting platform and one of the plurality of parking spaces. In a preferred embodiment, the dolly is dimensioned such that it may be inserted under a vehicle and between the vehicle&#39;s tires without damaging the vehicle. Unlike previous automated parking structures, however, the dolly of the present invention is dimensioned so as to have a height which is less than the space between the surface on which the vehicle is resting (such as the floor of the transfer room or parking space) and the vehicle body, known as the vehicle ground clearance. Because of this design, the floors of the transfer rooms and parking spaces of the present invention need not be specially constructed to accommodate the dolly. 
         [0015]    Once inserted under the vehicle, the dolly may deploy a number of tire engagement arms suitable for engaging the tires of a vehicle. Once the tires have been engaged, the dolly lifts the vehicle such that the vehicle tires are no longer in contact with the floor of a vehicle transfer room or parking space. Once the vehicle has been lifted, it may be moved between one of the vehicle transfer rooms and the lifting platform and/or between the lifting platform and one of the parking spaces. Furthermore, as described above, the dolly may be deployed from multiple sides of the vehicle transporter, allowing the dolly to access vehicles at multiple orientations relative to the vehicle transporter. 
         [0016]    The tire engagement arms, which are deployed in pairs for each tire, may lift the vehicle by any of a number of methods. For example, each tire engagement arm may move towards its paired tire engagement arm, squeezing under the lower portion of a tire, thereby lifting that tire from the floor. Alternatively, a pair of arms may remain engaged with the underside of the tire, yet stationary with respect to the tire, and may lift vertically thereby raising the tire from the floor. 
         [0017]    In another aspect of the present invention, the dolly may be comprised of a substantially rigid spine, and first and second slidable sections, with each slidable section carrying two pairs of tire engagement arms and deployable such that the tire engagement arms may engage a pair of tires associated with a single vehicle axle. Once each slidable section has reached a required position, dependant on the distance between the front and rear vehicle tires, at which the arms are correctly positioned to engage the tires associated with a single vehicle axle, the slidable sections are locked into place. In a preferred embodiment of the present invention, the first and second slidable sections are set to a desired position corresponding to the wheelbase of a vehicle to be engaged prior to insertion under the vehicle and advantageously while the transporter is moving to the location at which it will engage the vehicle. By presetting the relative position of the first and second slidable sections, economy of motion and time may be achieved as the apparatus need not determine the correct position for the slidable sections as a separate, subsequent step. Furthermore, each of the slidable sections may be independently operated and may be skewed relative to the central axis of the dolly, allowing the dolly to be steered. 
         [0018]    In various alternate embodiments, the vehicle parking structure may include guides for the dolly for the purpose of controlling travel of the dolly. For example, the vehicle parking structure may employ as a guide a series of grooves, magnetic tape, or chemical signals associated with the floor of the one or more vehicle transfer rooms and the plurality of parking spaces, which guide may be readable by the dolly. Each slidable section may also comprise one or more collision detectors, thereby allowing each slidable section to halt if a collision with an object is detected. 
         [0019]    In an alternate embodiment, the dolly may be configured such that it passes outside the vehicle tires, thereby eliminating the need to fit under the vehicle. In this embodiment the tire engagement arms are initially disposed outside the vehicle wheels and when extended, pass under the vehicle to engage the tires. 
         [0020]    In additional aspects of the present invention, the vehicle parking structure may also comprise a vehicle measuring and inspection system. The vehicle measuring and inspection system may perform any one or a combination of functions such as measuring the overall length, width, height, ground clearance and/or weight of a vehicle to be parked and ensuring that the dimensions of the vehicle fall within a pre-determined set of dimension guidelines; determining the position of the vehicle in the vehicle transfer room; determining if the vehicle includes any appendages which may adversely affect parking the vehicle; and measuring the wheelbase of the vehicle so that the dolly may adjust to the correct separation for the tires of the vehicle before the transporter reaches the vehicle. The vehicle measuring and inspection system may operate automatically using any of a number of technologies. For example, sensors and detectors employing any one of a number of electromagnetic frequencies may detect and measure the required dimensions of the vehicle. In a preferred embodiment, the sensors and detectors may comprise an array of laser scanners employing time of flight measuring technology to measure the vehicle and establish its position in the transfer room. The vehicle measuring and inspection system may also employ thermographic cameras to detect unusual heat sources and/or scales to detect unusual weight shifts within a vehicle, either possibly indicating that the vehicle is occupied; or a manual inspection and measuring of the vehicle may fulfill these functions. It should be noted that the vehicle measuring and inspection system and/or the parking management system discussed below, may also include sensors for recognizing a known vehicle, or known vehicle make and/or model such as would be encountered in a residential setting where tenants&#39; vehicles would be registered with the system, and thereafter modifying or eliminating the vehicle measuring and inspection steps based on information known about the subject vehicle. 
         [0021]    In an additional aspect of the present invention, the vehicle parking structure may also comprise a parking management system. The parking management system may include any one or a combination of functions such as accepting customer requests to return a vehicle; alerting a customer when a vehicle has been returned; offering a customer one or more specific times or a range of times when a vehicle is to be returned and accepting a customer response; monitoring the position and status of each of the one or more vehicle transporters; automatically moving to improve the efficiency of the parking structure such as by moving vehicles from remote parking spaces to spaces closer to the vehicle transfer rooms such that retrieval time is lessened once the vehicle is requested; providing one or more operational modes such as setup, maintenance, normal operation and emergency, including a vehicle fire mode in which a vehicle which is, or is suspected of being, on fire may be moved to a specific fire suppression area or otherwise removed from the parking structure; storing data regarding specific vehicles such that when a vehicle identification is received, either wirelessly or through some other method, the system may be able to implement certain functions such as presetting the dolly; and receiving vehicle measurement and position data from the vehicle measuring system, and thereafter adjusting the vehicle dolly accordingly and/or assigning vehicles to specific parking spaces according to the size of the vehicle and the size of the available parking spaces. 
         [0022]    In yet another aspect of the present invention, the parking management system may also include functionality allowing the parking management system to map the parking structure. In particular, the parking management system may adaptively learn the physical characteristics of the parking structure through interaction with the structure. For example, during a set up process, an operator may program the parking management system to define certain physical characteristics of the parking structure, for example, the number of parking spaces and transfer rooms, the physical dimensions of each parking space and transfer room, the location of any obstructions that may block a parking operation, and/or any other characteristics that may be noteworthy in the parking operation. Following the initial set up process, during a verification step, the operator or parking management system may instruct one or more of the vehicle transporters to travel to a specific location within the parking structure. Once at the specific location, the vehicle transporter may engage an indexing marker, such as a beacon, transponder, reflector or the like, and, based on the vehicle transporter&#39;s actual location when engaging the indexing marker, the parking management system may adjust the data representing the physical characteristics of the parking structure previously programmed during the initial set up process. In other words, the parking management system may compare an expected location of the indexing marker based on programmed data against the indexing marker&#39;s actual location and/or the location of the vehicle transporter when it recognizes the indexing marker and thereby identify any discrepancy with the programmed data. The parking management system may then continue to operate based on the programmed data, or may operate based on the new data received in the verification step. 
         [0023]    By mapping the parking structure based on both programmed data and verified data, the parking management system may compensate for at least two areas of error. First, the parking management system may identify errors in the programmed data entered in the set up process. Second, the parking management system may identify gradual variations in the parking structure or the vehicle transporters which may accrue over time. Specifically, changes in the physical characteristics of the parking structure occurring due to, for example, settling of the structure over time, and/or expansion and contraction due to thermal changes may be recognized and compensated for. Additionally, changes in the vehicle transporters due to, for example, component wear, and/or stretching of cables, chains and the like, may be recognized and compensated for by the parking management system. 
         [0024]    It should be noted that the parking management system may perform the verification step at any time during operation, and the parking structure may include any number of indexing markers. Thus, the parking management system may continuously verify the location of the vehicle transporters relative to known locations within the parking structure and adjust its operation accordingly. 
         [0025]    In yet additional aspects of the present invention, the vehicle parking structure may also comprise a vehicle occupant detection system which may use systems such as thermal imaging, motion detectors, and or other detectors to identify vehicles which may be occupied, such as by a child or a pet, and which are therefore unsuitable for parking. 
         [0026]    Furthermore, the vehicle parking structure may also comprise an appendage detection system suitable for detecting if a vehicle appendage such as a door, hatchback, trunk lid, hood, or tailgate has been left open, or if the vehicle has, e.g. bike racks, antennae or other appendages that may adversely impact the parking process. As movement of a vehicle with an unexpected appendage may cause damage to the vehicle, other vehicles within the parking structure, and/or vehicle parking structure itself, the system restricts movement of such a vehicle. In an alternate embodiment, the appendage detection system may also include an appendage restraint system which may act to prevent damage to the vehicle or vehicle parking structure in the event that a vehicle is moved with one or more appendages. 
         [0027]    The present invention may also include an alignment/level maintenance device whereby the lifting platform may engage the vehicle parking structure to ensure that the lifting platform remain adjacent to/level with a parking space while a vehicle is being loaded or off-loaded. Finally, the vehicle parking structure may also include one or more maintenance vehicles which may or may not operate autonomously or semi-autonomously and are used in the servicing of various elements of the vehicle parking structure and may also incorporate fire suppression technologies. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0028]    The invention will be better understood with reference to the drawings taken in connection with the detailed description which follows: 
           [0029]      FIG. 1  is a schematic of the vehicle parking structure of the present invention; 
           [0030]      FIG. 1A  is a close up of certain elements depicted in  FIG. 1 ; 
           [0031]      FIG. 2  shows an alternative embodiment of the parking structure with mast, upper and lower tractors and vehicle transporter; 
           [0032]      FIG. 3  shows an alternative embodiment of the present invention with shafts or cables replacing the mast; 
           [0033]      FIG. 3A  shows one embodiment of a vertical stabilizer utilizing a four post design; 
           [0034]      FIG. 4  shows one embodiment of a parking structure of the present invention with two vehicle transporters able to service all the parking spaces; 
           [0035]      FIG. 5  shows one embodiment of a lifting platform and dolly of the present invention; 
           [0036]      FIG. 6  shows one embodiment of the dolly of the present invention with the tire engagement arms in the closed position; 
           [0037]      FIG. 7  shows one embodiment of the dolly of the present invention with the tire engagement arms in the extended position; 
           [0038]      FIG. 8  shows one embodiment of the dolly of the present invention with the tire engagement arms in the extended and pinched position; 
           [0039]      FIG. 9  shows one embodiment of the dolly of the present invention, specifically a mechanical linkage responsible for extending the tire engagement arms; 
           [0040]      FIG. 10  shows one embodiment of one of the slidable sections which, in part, comprise the dolly; 
           [0041]      FIG. 11  shows one embodiment of the dolly of the present invention with the first and second slidable sections in a starting position; 
           [0042]      FIG. 12  shows one embodiment of the dolly of the present invention with the first and second slidable sections in an open position; 
           [0043]      FIG. 13  depicts one embodiment of the dolly and lifting platform in which the dolly has been deployed from a lifting platform; 
           [0044]      FIG. 14  depicts a lifting platform and dolly with the dolly retracted; 
           [0045]      FIG. 14   a  depicts a lifting platform and dolly with the dolly extended under a vehicle; 
           [0046]      FIG. 15  is a schematic view of a push/pull mechanism associated with a dolly; 
           [0047]      FIGS. 16-18  depict the operation of a tilt mechanism of the present invention enabling a lifting platform to access parking spaces positioned on multiple sides of the lifting platform; 
           [0048]      FIG. 19  depicts a flowchart representing the operation of a parking structure mapping operation of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0049]      FIGS. 1 and 1A , depict a section of the interior of vehicle parking structure  10  of the present invention. The parking structure  10  comprises at least one vehicle transfer room  12  and a plurality of parking spaces  16 . The parking structure  10  also comprises framework  44  suitable for maintaining the structural integrity of the structure and, in the embodiment depicted in  FIG. 1 , for dividing the individual parking spaces  16 . It should be noted that as depicted, framework  44  does not separate each and every parking space  16 . Rather, long horizontal spans are employed, enabling an operator to vary the area allotted for each parking space  16 . This embodiment may be preferable in installations wherein the ability to alter the size of each parking space  16  is desired. However, as will be shown if  FIGS. 2 and 4 , alternate layouts of framework  44  may be employed without departing from the scope of the invention. Finally, it should also be noted that although the figures generally depict an arrangement wherein the parking spaces  16  are placed above the transfer rooms  12 , an alternate embodiment wherein the transfer rooms  12  are above the parking spaces  16  (such as if the parking spaces were subterranean), or where the transfer rooms  12  were placed at some intermediate location within the array of parking spaces  16  (such as if the parking spaces  16  were both subterranean and above ground), would not deviate from the scope of the invention. 
         [0050]    Within the vehicle parking structure  10 , one or more vehicle transporters  18  may operate. In the embodiment depicted in  FIG. 1 , the vehicle transporter  18  is comprised of vertical stabilizer  20 , tractor  22 , a set of unpowered guide wheels  23 , and as shown in more detail in  FIG. 1A , lifting platform  26 , winch  24 , and dolly  30 . The unpowered guide wheels  23  may derive motion from the force transmitted by the vertical stabilizer  20  being moved by the tractor  22 , and both the tractor  22  and the unpowered guide wheels  23  may be guided by rails  46 . The tractor  22  must have sufficient power and structural strength to move itself, the vertical stabilizer  20  and the unpowered guide wheels  23 . The vertical stabilizer  20  must be of sufficient strength to transmit the force required to cause the unpowered guide wheels  23  to move in unison with the tractor  22 . The vertical stabilizer  20  must also have sufficient strength to resist bending and to maintain its shape so that the position of the vehicle transporter  18  can be known by the control system  21 . Although  FIG. 1  depicts the tractor  22  at the bottom of the parking structure  10  and the unpowered guide wheels  23  at the top of the parking structure  10 , those positions could be reversed without deviating from the scope of the invention. Furthermore, a system in which the tractor  22  was located at a point intermediate along the vertical stabilizer  20  and the guide wheels  23  were placed elsewhere along the vertical stabilizer  20  would not deviate from the scope of the invention. Alternatively, the tractor  22  could be removed from the vehicle transporter  18  and replaced with a set of guide wheels  23 . In such an embodiment, each vehicle transporter  18  could be associated with, and derive motion from, one or more tractors  22  fixedly located within the parking structure  10  and acting as winches. A chain, cable or other connector could be employed to transmit motion from the one or more tractors  22  to the guide wheels  23  or other point along the vehicle transporter  18 . 
         [0051]    As was noted above, the parking structure  10  may also comprise one or more rails, tracks or the like  46  which may engage the tractor  22  and the unpowered guide wheels  23  providing guidance for the tractor  22  and the unpowered guide wheels  23  and which may also support the weight of the vehicle transporter  18  and, when loaded, a vehicle  14 . 
         [0052]    In the present embodiment, the lifting platform  26  is in turn comprised of rotary table  28  and dolly  30 . As depicted more clearly in  FIG. 1A , a vehicle  14  is engaged by the dolly  30 . The lifting platform  26  can be independently raised or lowered on the vertical stabilizer  20  by use of a winch  24 , which in one embodiment is an electrically powered winch attached to lifting platform  26  and counterweight  48  by a lifting chain or cable  50 . Alternatively, the winch  24  may be mounted on the lifting platform  26  and/or may act to raise and lower the lifting platform  26  by way of a toothed drive system such as by driving a gear which engages a toothed track mounted on the vertical stabilizer  20 . 
         [0053]    Turning to  FIG. 2 , in a preferred embodiment, powered tractors  22  are located at both the top and the bottom of the vertical stabilizer  20 . Because both ends of the vertical stabilizer  20  are driven, it may no longer be necessary for the vertical stabilizer  20  to have sufficient strength and rigidity such as may be required to transmit driving force from a single tractor  22  to a set of unpowered guide wheels  23 , as was depicted in  FIG. 1 . However, this may be true if the position of each tractor  22  is maintained relative to the other. Thus synchronizer  25  may be provided to maintain this positioning by, for example, mechanical mechanisms. In one embodiment, a shaft and gears can be used to connect the two tractors. In other embodiments the mechanisms could use a chain, a toothed belt or belts or other mechanical means. Alternatively, electronic means may be used to provide position information to an electronic controller. In this embodiment, devices generate electronic signals that are related to the motion and/or position of each tractor  22 . An electronic controller can use those signals in its control logic to establish the position of each tractor  22 , both in absolute and relative terms. In addition, the controller can cause either or both tractors  22  to adjust position so that the desired position of each tractor  22  is maintained. The electronic means is the preferred embodiment for this invention. 
         [0054]      FIG. 2  also depicts an embodiment of the present invention in which the vertical stabilizer  20  is mounted to the upper and lower tractor  22  by a non-rigid connection  27  such as a hinge or ball and socket joint. Driving the upper and lower tractors  22  in a coordinated fashion will allow the vertical stabilizer  20  to be mounted in a non-rigid fashion thus avoiding or lessening induced moments into the vertical stabilizer  20  and/or the tractors  22 . Since induced moments may be either eliminated or reduced, the driven wheels  29  of the tractors  22  and the track  46  will not have to resist those loads. Also, the strength requirements for the vertical stabilizer  20  may be reduced. It should also be noted that although tractor  22  is depicted as having wheels  29 , and the unpowered drive wheels  23  are shown as having wheels, the use of wheels is not a necessary part of the present invention. Tracks, slides or the like may be substituted without deviating from the scope of the invention. 
         [0055]    Additionally, as depicted in  FIG. 2  and  FIG. 4 , the use of a non-rigid connection  27  between the vertical stabilizer  20  and/or the tractors  22  may allow a narrower tractor wheelbase  31  because it is no longer providing stability and vertical positioning for the vertical stabilizer  20 . The narrow wheelbase  31  also allows a smaller end zone  54  for parking a vehicle transporter  18  thus allowing the adjacent vehicle transporter  18   a  to reach the parking slots normally serviced by the parked vehicle transporter  18 . As noted earlier,  FIGS. 2 and 4  also depict an alternate embodiment of framework  44 . In this embodiment, vertical elements of framework  44  divide each parking space  16 . Although this embodiment may restrict an operators ability to easily alter the area allotted for each parking space  16 , it has advantages in cost and vertical space saving. Specifically, the use of additional vertical elements in framework  44  allows for the use of shorter horizontal spans. Because these horizontal elements have a reduced span, they need not be as thick as the longer spans depicted in  FIG. 1 . Thus, the overall height of each level of parking spaces may be reduced. 
         [0056]    As seen in  FIG. 2 , the vertical stabilizer  20  includes an automatic length compensator/adjustor  52  that allows the vertical stabilizer  20  to expand and contract in the direction of the major axis (in this case vertical) while preventing the vertical stabilizer  20  from deviating significantly from the normal straight line orientation. This feature will allow for variations in the distance between the upper and lower tractors  22 . 
         [0057]    As depicted in  FIG. 2 , the vertical stabilizer  20  will not be compressively loaded as it is supported by the upper tractor  22 , which is in turn supported by the upper rail  46 . The vertical stabilizer  20  will be in tension or bending or both depending on the selected lift method. In a preferred embodiment, the arrangement of the winch  24  and the lifting platform  26  will be such that the vertical stabilizer  20  is not subjected to the compressive forces associated with lifting the vertical load of the lifting platform  26  and, if present, a vehicle  14 . In this embodiment, this load will be taken by one or both of the tractors  22 , or if present, the unpowered guide wheels  23 . This load may then be transferred directly to the rails  46 , and from there to the framework  44 , or if applicable, to the foundation or floor of the parking structure  10 . The vertical stabilizer  20  may be subjected only to the loading associated with the bending moments from supporting the lifting platform  26  and, if present, a vehicle  14 , and the reaction forces to the movement of the rotary table  28  if present. This feature, in combination with the automatic adjustor  52 , may reduce the strength requirements for the vertical stabilizer  20 , which in turn may allow for a lighter, and less costly vertical stabilizer  20 . Furthermore, a lighter vertical stabilizer  20  will also reduce the horsepower required to accelerate and stop the vehicle transporter  18 , as well as reduce the strength requirements of the components to which it attaches such as the rails  46 , and indirectly, the framework  44 . 
         [0058]    In the two different embodiments disclosed above and shown in  FIGS. 1 and 2 , the vertical stabilizer  20  takes the form of a substantially rigid mast-like structure. Turning now to  FIG. 3 , in an alternate embodiment, the vertical stabilizer  20  may take the form of one or more vertically oriented guides such as cables, shafts or the like. The vertical guidance of the lifting platform  26  is provided by the stiffness of the shaft or cable. As with the previous embodiment, automatic adjustors  52  are provided in this embodiment as well, although the sizing function may be accomplished by one or more springs or slip bearings. If the shafts or cables, mounted to the upper and lower tractors  22 , can not provide sufficient stiffness, an intermediate tractor  22   a  can be provided to impart additional resistance to deflection. 
         [0059]    Turning to  FIGS. 3   a  and  5 , in a preferred embodiment, the vertical stabilizer  20  of a vehicle transporter  18  may be comprised of a plurality of vertical elements formed in a frame. As in the previous figures, a winch  24  may be provided to supply lifting power, while the tractor(s)  22  may be provided to supply horizontal movement. Of course, as previously described, the tractor(s)  22  may be replaced with unpowered guide wheels  23  and/or moved to various locations either on the vehicle transporter  18  or to various locations within the parking structure  10 . As shown in  FIGS. 3   a  and  5 , the use of a plurality of vertical stabilizers  20  may provide the benefit of added stability within the vehicle transporter  18  as the use of multiple vertical stabilizers  20  may distribute any loads associated with the lifting platform  26 , and, if present, a vehicle  14 . 
         [0060]    In one embodiment of the parking structure, illustrated in  FIG. 4 , the vehicle transporters  18 ,  18   a  and the parking structure  10  are designed to allow either vehicle transporter  18 ,  18   a  to service all of the parking spaces  16 . In this embodiment, the vehicle transporters  18 ,  18   a  are designed such that the lifting platforms  26 ,  26   a  face each other and/or overlap in their reach. As shown, the lifting platform  26  extends to the right of the vehicle transporter  18  such that when the vehicle transporter  18  is parked in the end zone  54 , the lifting platform  26  may still reach the parking spaces  16  and the transfer room  12  in the leftmost column of the parking structure  10 , labeled as spaces  1 - 1  through  7 - 1  and transfer room A. Furthermore, the lifting platform  26   a  associated with the vehicle transporter  18   a,  extends to the left of the vehicle transporter  18   a  such that it overlaps the lifting platform  26  and is also able to access the parking spaces  16  and the transfer room  12  in the leftmost column of the parking structure  10 , labeled as spaces  1 - 1  through  7 - 1  and transfer room A. Note that without this opposing/overlapping orientation of the lifting platforms  26 ,  26   a,  lifting platform  26   a  would be unable to access spaces  1 - 1  through  7 - 1  and transfer room A. Specifically, associated vehicle transporter  18   a  would be unable to traverse far enough to the left to align the lifting platform  26   a  with those spaces and transfer room as vehicle transporter  18   a &#39;s path would be blocked by vehicle transporter  18 . The inability to access one or more of the spaces  16  and transfer rooms  12  may be especially disadvantageous in the event that one or more of the vehicle transporters  18  are rendered inoperable through breakdown or routine maintenance which may strand one or more vehicles in the parking structure  10 . While the overlapping orientation depicted here possesses the advantages described, an alternate orientation wherein the lifting platforms  26 ,  26   a  do not overlap, are able to access all of the spaces  16  and transfer rooms  12  without overlapping, or wherein each vehicle transporter was not able to service the entire parking structure, would not deviate from the scope of the present invention. Furthermore, in certain applications, due to design considerations such as cost and available space, a non-overlapping orientation, or a design in which each vehicle transporter was not able to service the entire parking structure may be preferred. 
         [0061]    Furthermore, as depicted in  FIG. 4 , in a preferred embodiment, the parking structure  10  may be constructed with multiple arrays of parking spaces  16 . In particular, in a preferred embodiment, the vehicle transporters  18  are restricted to linear travel along a path within the vehicle parking structure  10 . Parking spaces  16  may be arrayed on opposite sides of the vehicle transporter  18 , perpendicular to the direction of travel of the vehicle transporter  18 . As will be discussed in greater detail in the discussion of  FIG. 15 , dolly  30  may be deployed from multiple sides of the vehicle transporter  18  such that it may service parking spaces  16  on corresponding sides of the vehicle transporter  18 . 
         [0062]    Turning to  FIGS. 5 and 13  in combination, one embodiment of the lifting platform  26 , dolly frame  110  and dolly  30  is depicted. Although the structure associated with a rotary table is not depicted in  FIG. 5 , the use of a rotary table is depicted as dolly frame  110  is shown skewed relative to lifting platform  26 . Again, although the structure associated with a rotary table is not shown in  FIG. 5 , such structure enables the dolly  30  to rotate about an axis, while the dolly  30  provides a substantially planar top surface  56  having a major axis  58  and a minor axis  60 , and a substantially centrally located slot  62  orientated along the major axis  58  through which spine  36  and tongue  114  travel. The top surface  56  and the dolly  30  are orientated so that substantially all of portions of the dolly  30  that travel underneath a vehicle  14  are located above the top surface  56 . In particular, the first slidable section  32 , the second slidable section  34 , the spine  36 , the tongue  114 , and the tire engagement arm pairs  64   a - 64   d  are able to pass above the top surface  56 . As will be discussed in greater detail in the discussion below, the dolly  30  is operationally engaged with the lifting platform  26  such that the dolly  30  may be deployed from the lifting platform  26  and positioned under a vehicle  14 , whereupon it may engage and lift the vehicle  14  such that it may be moved on or off of the lifting platform  26 . 
         [0063]    In a preferred embodiment, the lifting platform  26  and/or the dolly  30  may be tilted about the minor axis  60 , by a tilt actuator employing one or more of a number of known technologies. For example, an automated hydraulic jack may engage the lifting platform  26  and the dolly  30  to tilt the dolly  30  relative to the lifting platform  26 . Alternately, the lifting platform  26  may be tilted from horizontal with the winch  24  acting as a tilt actuator. For example, the winch  24  may engage the lifting platform  26  by one or more cables, chains or the like attached at various points on the lifting platform  26 . By selectively engaging one or more of such cables, chains or the like, the winch  24  may tilt the lifting platform  26  which carries the dolly  30 . It may be appreciated that each of the parking spaces  16  associated with the parking structure  10  has a substantially planar floor  17 . To facilitate water run off from either rain or snow carried in by a vehicle  14  or for cleaning operations, the floor  17  may be tilted relative to the horizontal plane, generally such that the edge of the floor  17  adjacent to the lifting platform  26  is higher than the opposite end. However, because of the tilt in the floor  17 , if the dolly  30  were deployed from the lifting platform  26  in a substantially horizontal manner, the dolly  30  would be subjected to bending loads along the spine  36  and/or tongue  114  caused by the leading edge of the dolly  30  being cantilevered over the floor  17 . By tilting the lifting platform  26  to an angle that substantially matches the angle of the floor  17 , the bending loads along the spine  36  and/or tongue  114  may be greatly reduced as the leading edge of the dolly  30  will engage the floor  17  relatively quickly once it has been deployed. 
         [0064]    Turning to  FIG. 6 , the dolly  30  is depicted in a first closed position, with the top surface  56  depicted in phantom. The dolly  30  is comprised of a first slidable section  32 , a second slidable section  34 , a spine  36 , and tire engagement arm pairs  64   a    64   d.  Each tire engagement arm pair  64   a - 64   d  is deployed to engage a single tire of a vehicle  14  to be moved. The tire engagement pairs  64   a - 64   d  are associated with the first and second slidable sections  32  and  34 . As depicted, the first slidable section  32  is associated and moves with, tire engagement arm pairs  64   a  and  64   b,  while the second slidable section  34  is associated and moves with tire engagement arm pairs  64   c  and  64   d.  Thus, each slidable section  32 ,  34 , in connection with its associated tire engagement arm pairs  64   a,    64   b  and  64   c,    64   d  respectively, engages the tires associated with a single vehicle axle. In operation, the first and second slidable sections  32  and  34  are displaced along the major axis  58  such that they accommodate the wheelbase of the vehicle  14  to be moved. As is best seen in  FIG. 7 , once in place, the first and second slidable sections  32  and  34  may be temporarily locked in place by locking mechanism  35 . In a preferred embodiment, the displacement of the first and second slidable sections  32  and  34  may be performed prior to or during deployment of the dolly  30  under the vehicle  14 . In a preferred embodiment, the vehicle parking structure  10  may also include a vehicle measuring system capable of measuring and storing at least the wheelbase of a vehicle  14  to be moved. Since the vehicle wheelbase is known prior to the vehicle transporter  18  reaching the vehicle  14 , it is possible to preadjust the displacement of the first and second slidable sections  32  and  34  prior to insertion under the vehicle  14 . By preadjusting the slidable section displacement, valuable time is saved during the vehicle movement process as the steps of measuring and adjusting the slidable sections  32  and  34  does not need to be undertaken after the vehicle transporter  18  reaches the vehicle  14  or after the dolly  30  is positioned under the vehicle  14 . 
         [0065]    Turning to  FIG. 7 , slidable section  32  of the dolly  30  is depicted in a second open position. While the following discussion will focus only on slidable section  32 , it should be understood that it is equally applicable to slidable section  34  and corresponding elements of the slidable section  34 . In this figure, the tire engagement arm pairs  64   a  and  64   b  have been opened such that they are substantially parallel to the minor axis  60 . Each of the tire engagement arm pairs  64   a    64   b  are comprised of at least two tire engagement arms  66 , which in the embodiment depicted, are substantially wedge-shaped and oriented such that leading edge of each wedge is positioned to first engage a vehicle tire, however, the arms  66  may take other shapes without departing from the scope of the invention. Each of the arms  66  is supported at its inboard edge by a hinged connection  68  with the slidable section  32 , and by one or more wheels  70  at its outboard edge. Referring back to  FIG. 6 , it is of note that when in the first closed position, the arms  66  are not carried parallel to the top surface  56 . In particular, the wheels  70  are raised from the top surface  56  by an angle of loft  72 . The angle of loft  72  is sized such that the wheels  70  do not contact the top surface  56  as, while in closed the position, the wheels  72  are transverse to the direction of travel along the major axis  58 . Thus, without the angle of loft  70 , when the dolly  30  or the slidable sections  32  or  34  were moved in the direction of the major axis  58 , the wheels  70  would create undesirable drag, hindering performance of the dolly  30 . 
         [0066]    Returning to  FIG. 7 , it can be seen that each of the arms  66  associated with tire engagement arm pairs  64   a  and  64   b,  are separated from their respective pair by a separation distance  74 . In general, the separation distance  74  is set by the overall dimensions of the slidable section  32  or  34  with which it is associated, but at a minimum is large enough to accommodate a vehicle tire. 
         [0067]    Turning to  FIG. 8 , the dolly  30  is depicted in a third pinched position. In this position, the separation distance  74  has been reduced relative to that shown in  FIG. 7 , and thus each of the arms  66  is now relatively closer to its pair. In a preferred embodiment, the separation distance  74  is now, at a maximum, small enough to ensure that the tires of the vehicle  14  have been lifted from the surface of the lifting platform  26  or parking space  16 . In a more preferred embodiment, the separation distance  74  is approximately 6.3 inches. The separation distance  74  is closed through the action of pinching actuator  76 . In a preferred embodiment, the pinching actuator  76  comprises an electro/mechanical linear actuator although alternate designs such as the use of a hydraulic actuator, servo motors or mechanical linkages may also be used without departing from the scope of the invention. In a preferred embodiment, the pinching actuators  76  are also responsible for extending the arms  66  from the closed position depicted in  FIG. 6  and to the open position shown in  FIG. 7 . 
         [0068]    Turning to  FIG. 9 , in a more preferred embodiment, the pinching actuator  76  operates on the arms  66  via a mechanical linkage. A first end  90  of the pinching actuator  76  may be hingedly connected to frame  78  of the slidable section  32  or  34 . A second end  92  of the pinching actuator  76  may be hingedly connected to first linkage arm  94 . The first linkage arm  94  includes first and second hinge points  96  and  98 . The first hinge point  96  is hingedly connected to slidable section upper plate  97  while the second hinge point  98  is hingedly connected to first end  100  of second linkage arm  102 . Finally, second end  104  of the second linkage arm  102  is hingedly connected to the arm  66 . The pinching actuator  76 , first linkage arm  94  and second linkage arm  102  are preferably dimensioned such that, in operation, once the pinching actuator  76  has fully operated against the first linkage arm  94 , the arm  66  will be fully extended and substantially perpendicular to the major axis  58 . Furthermore, the first linkage arm  94  and the second linkage arm  102  will be in an over center or hyper extended relation such that they are in a non-linear relation while the hinge  106  defined by the second hinge point  98  and the first end  100  is in contact with an adjustable stop (not shown). Alternatively, the hinge defined by the second hinge point  98  and the first end  100  could be in contact with the arm  66  or some other structure which limits its movement and prevents additional flexing of the hinge. With this arrangement, any force  108  exerted on the arm  66  by a tire of the vehicle  14 , which would otherwise act to collapse the arm  66 , will instead be arrested by the contact between the hinge  106  and the adjustable stop (not shown). The arm  66  will collapse to a position adjacent to the frame  78  when the pinching actuator  76  retracts, pulling the first linkage arm  94  and the second linkage arm  102  out of the over center or hyper extended orientation and allowing them to collapse against each other. In an alternate embodiment, the arms  66  may be locked in the extended position during vehicle engagement through the use of a pin or other mechanical means. Alternatively, the force applied by the pinching actuator  76  may be sufficient to prevent the arm  66  from collapsing against the frame  78 . 
         [0069]    As discussed above, the dolly  30  is comprised, in part, of first and second slidable sections  32  and  34 . Turning to  FIG. 10 , a single, representative slidable section  32  or  34  is shown. The slidable sections  32  and  34  are comprised of a generally rectangular, box steel frame  78  with a central cross brace  80 , although alternate materials with alternate cross sections could be used to construct the frame  78  such as composites or plastics without deviating from the scope of the invention. In the embodiment depicted, six (6) wheels  82  are mounted along the perimeter of the frame  78 , although an alternate number of wheels placed in alternate configurations would also be acceptable. In a preferred embodiment the wheels  82  are 3 inch outside diameter by 1.75 inch wide polyurethane wheels manufactured by Sunray, Inc. of Rutherfordton, N.C. When a vehicle  14  is loaded onto the dolly  30 , the wheels  82  and arm wheels  70  bear the load of the vehicle. The Dolly  30  further comprises rollers  84  which engage the spine  36  (depicted in  FIGS. 5-8 ). The rollers  84  act to align the slidable sections  32  and  34  with the spine  36  to encourage linear travel of the dolly  30 . 
         [0070]    Turning to  FIG. 11 , the dolly  30  is again depicted with the slidable sections  32  and  34  and the spine  36 . Here, the slidable sections  32  and  34  are depicted in a first, proximate position. Turning to  FIG. 12 , the slidable sections  32  and  34  are depicted in a second, distant position. With reference to both  FIGS. 11 and 12 , separators  86  are depicted. In a preferred embodiment, the separators  86  comprise one or more devices capable of moving the slidable sections  32  and  34  relative to each other. Examples of suitable devices include electro/mechanical linear actuators, lead screw mechanisms and/or hydraulic rams mounted substantially parallel to the major axis  58  and fixedly connected at opposing ends to the slidable sections  32  and  34  respectively such that operation of the separators  86  acts to increase or decrease the separation between the slidable sections  32  and  34 . In operation, in a preferred embodiment, as the dolly  30  is extended under a vehicle  14 , the slidable sections  32  and  34  are pre-positioned to match the wheelbase of the vehicle  14 . As previously discussed, this pre-positioning eliminates the need to accomplish the sizing function after the dolly  30  has been placed under the vehicle  14 , potentially reducing the time necessary to engage the vehicle  14 . 
         [0071]    Turning to  FIG. 13 , the dolly  30  is depicted as fully extended from the lifting platform  26 . The spine  36  is extended, and the slidable sections  32  and  34  are in the proximate position while the arms  66  are in the closed position. One or more collision detectors  88  may be affixed to the dolly  30  such that in the event vehicle transporter contacts a person or structure, the collision detector  88  may sense the contact, and preferably halt or reverse motion of the dolly  30 . Collision detectors  88  may be of any one of a number of known technologies. For example, collision with an object may cause the movement or deflection of a collision detector  88  which in turn may complete an electric circuit or compress a piezoelectric load cell creating a signal which may alert the dolly  30  to quickly halt or reverse direction. Collision detection is a well-studied art and of particular use in the robotics industry. As such, companies such as RAD of Tipp City, Ohio supply collision detection systems utilizing pneumatics and/or mechanical triggering systems to the robotics industry. Similarly, U.S. Pat. No. 4,821,584 to Lembke illustrates a collision detection system including a piezoelectric load cell. 
         [0072]      FIGS. 14 ,  14   a  and  15  further illustrate additional aspects and details of the dolly  30 . In these figures, the terms left and right are used to describe locations and movement in relation to the figures and should not be taken as any limitation of the present invention. 
         [0073]      FIG. 14  depicts dolly  30  positioned adjacent to a vehicle  14  which is positioned on the floor  17  of a parking space  16 . Of course, the same arrangement would be found if the vehicle  14  were positioned in a transfer room  12 .  FIG. 14   a  depicts dolly  30  having deployed the first slidable section  32 , the second slidable section  34 , and the spine  36  under the vehicle  14 . Of course, additional elements, such as the tire engagement arm pairs  64   a - 64   d  and the wheels  82  (depicted in  FIG. 6 ) are also deployed under the vehicle  14 , however, they are not distinguishable in  FIG. 14   a . However, as shown in  FIG. 14   a  the deployed elements of the dolly  30  are dimensioned such that they fit between the floor  17  of the parking space  16  and bodywork of the vehicle  14 . In other words, it will be understood that the wheels  82  travel on the same plane as that on which the tires of the vehicle  14  travel. Specifically, in a preferred embodiment, the height of the deployed elements of the dolly  30  are less than about 4.0 inches, and in a more preferred embodiment, less than abut 3.8 inches. 
         [0074]    Turning to  FIG. 15 , in a preferred embodiment, a push/pull mechanism associated with dolly  30  is depicted. The push/pull mechanism is comprised of frame  110 , carriage  112 , tongue  114 , the spine  36 , carriage/spine cable  116 , carriage tongue cable (left)  118 , carriage tongue cable (right)  120 , carriage drive chain  122 , drive motor  124 , and a number of attachment points, guides and pulleys described in more detail below. As shown schematically in  FIG. 15 , the drive motor  124  is mounted within the frame  110  and connected by the carriage drive chain  122  to the carriage  112 . The drive chain  122  is routed around drive sprocket  125  and then the first and second idler sprockets  126  and  128 , first and second carriage sprockets  130  and  132  and fixedly mounted to the carriage  112 . In operation, the rotation of the drive motor  124  in a counterclockwise direction as depicted in  FIG. 15  will result in the movement of the carriage  112  from right to left. Clockwise rotation of the drive motor  124  will result in movement of the carriage  112  from left to right. In either case, the carriage  112  is supported and guided in its travel by guide rails  134 . Of course, alternate motive mechanisms and layouts could be implemented without deviating from the scope of the invention. For example, the drive motor  124  could be mounted within the carriage  112  and could drive the carriage  112  by means of a gear fixedly mounted to the drive motor  124  engaging a toothed track mounted along or integral with the guide rails  134 . 
         [0075]    As the carriage  112  travels in the right to left direction, it engages a number of additional cables and pulleys which translate and amplify the motion of the carriage  112  to the tongue  114  and the spine  36 , causing the deployment of the spine  36  to the left of the frame  110 . As shown, the carriage tongue cable (left)  118  is fixedly mounted to the frame  110  at frame attachment point (left)  138 , travels in a generally vertical orientation, wrapping around the main pulley stack  136 , the frame pulley stack (left)  142 , the frame pulley stack (right)  144 , and is fixedly attached to the tongue  114  at tongue attachment point (left)  146 . Similarly, the carriage tongue cable (right)  120  is fixedly mounted to the frame  110  at frame attachment point (right)  140 , travels in a generally vertical orientation, wrapping around the main pulley stack  136 , the frame pulley stack (right)  144 , the frame pulley stack (left)  142 , and is fixedly attached to the tongue  114  at the tongue attachment point (right)  148 . It will be appreciated that, although not depicted in  FIG. 15 , pulley stacks  136 ,  142  and  144  are each comprised of multiple pulleys which are able to spin independently of each other. As the carriage  112  moves right to left, the carriage tongue cable (left)  118 , and the carriage tongue cable (right)  120  transmit the motion of the carriage  112  to the tongue  114  which is supported and guided by, for example, an inverted C-channel which interfaces with the frame  110 . Furthermore, because the carriage tongue cable (left)  118 , and the carriage tongue cable (right)  120  are wrapped around the main pulley  136  which moves with the carriage  112 , the motion of the carriage  112  is doubled as applied to the tongue  114 , similar to the manner in which a block and tackle operates. That is, the inclusion of the main pulley  136  serves to translate every one unit of horizontal movement of the carriage  112  into two units of horizontal movement of the tongue  114 . 
         [0076]    Furthermore, the carriage  112  is also fixedly mounted to the carriage spine cable  116  at the carriage attachment point  150 . The carriage spine cable  116  is looped around first and second tongue pulleys  152 ,  154  in a generally horizontal orientation. The tongue pulleys  152  and  154  are rotatably mounted to the tongue  114  such that the tongue pulleys  152  and  154  move in unison with the tongue  114 . Finally, the spine  36  is fixedly attached to the carriage spine cable  116  at tab  156 . The motion of the carriage  112  in the right to left direction is thus transmitted to the spine  36  via the carriage spine cable  116 . The spine  36  is supported and guided by a system of blocks fixed to the spine  36  which engage channels in the tongue  114  thereby ensuring substantially linear movement of the spine  36  in relation to the tongue  114 . This arrangement of blocks and channels could, of course, be reversed and alternate means of ensuring linear travel could be substituted without deviating from the scope of the invention. 
         [0077]    It should be noted that because the spine  36  is fixedly mounted to the carriage spine cable  116 , and that the carriage spine cable is mounted to the tongue  114  via the tongue pulleys  152  and  154 , any travel of the carriage  112  is naturally transmitted to the spine  36  through its connection with the tongue  114 . Thus, as with the tongue  114 , every one unit of travel by the carriage  112  results in two units of travel of the spine  36 . However, the carriage  112  is also transmitting motion to the spine  36  via the carriage spine cable  116 , resulting in an additional one unit of travel for the spine  36  for every unit of travel of the carriage  112 . Thus, taken together, for every one unit of travel of the carriage  112  in the right to left direction, the spine  36  experiences three units of travel in the right to left direction. Of course, the motion of the carriage  112  in the left to right direction simply reverses all of the previously described motion making it possible to deploy the spine  36  to the right of the frame  110 . 
         [0078]    As a result of the arrangement of the spine  36 , the tongue  114  and the carriage  116 , small movements of the carriage  112  are amplified three times in the spine  36 . The benefit in this arrangement is that while the movement of the carriage  112  is limited within the frame  110 , the spine  36  must be able to extend fully under the vehicle  14  such that the arms  66  may engage all four tires of the vehicle  14 . Of course, alternate embodiments of motion amplifiers, such as the use of different sized gears responsible for imparting motion to the different components are possible without deviating from the scope of the invention. 
         [0079]    In operation, a vehicle  14  may be parked within the vehicle parking structure  10  as follows. First, a vehicle may enter one of one or more of the vehicle transfer rooms  12 . Once in the vehicle transfer room  12 , the vehicle  14  may be measured for overall dimensions of length, width, height, ground clearance and wheelbase to ensure that each dimension falls within pre-determined parameters, and its position within vehicle transfer room  12  may also be measured. In particular, the location of the vehicle  14  relative to one or more known reference points such as the walls of the vehicle transfer room  12  may be determined, as well any skew of the vehicle relative to the walls of the vehicle transfer room  12 . Alternately, if the vehicle  14  is known to the vehicle parking structure  10 , such as if the vehicle transmits an identification signal to the system or if the vehicle is otherwise identified to the vehicle parking structure  10 , a determination step, rather than a measuring step may be carried out. In particular, based on the vehicle identification received by the vehicle parking structure  10 , a lookup table containing the vehicle identification correlated with vehicle characteristics such as the vehicle&#39;s spatial dimensions, could be consulted to determine the vehicle&#39;s  14  length, width, height and wheelbase. Of course, the step of determining the position of the vehicle  14  within the vehicle transfer room  12  could still be carried out. Furthermore, rather than completely eliminating the vehicle measuring step, a reduced or modified measurement could be taken to ensure that the determined vehicle characteristics match the actual characteristics of the vehicle  14  in the vehicle transfer room  12 . Alternately, the vehicle  14  may be measured or its spatial dimensions determined prior to its entering a transfer room  12 . 
         [0080]    Once the dimensions and position of the vehicle  14  are either measured or determined, this data may be transferred to the control system  21 . The control system  21  may then pre-adjust one of the one or more vehicle transporters  18 , specifically the positions of the slidable sections  32  and  34 , to correspond to the measured or determined wheelbase of the vehicle  14 . Control system  21  may also perform additional functions such as determining optimal placement of the vehicle  14  within the parking structure  10 . Specifically, based on the dimensions of the vehicle  14 , the control system may select a parking space  16  in which to place vehicle  14  from a range of available parking spaces  16  which may have varying dimensions. Control system  21  may select an available parking space  16  which will best accommodate vehicle  14 . 
         [0081]    The vehicle parking structure  10  may also perform a vehicle occupancy step to verify that the vehicle  14  is unoccupied. Once the vehicle parking structure  10  has determined that the vehicle  14  is unoccupied (either by a signal given by an operator or through one or more automated means) and acceptable for movement, if available, one of the one or more vehicle transporters  18  will approach the transfer room  12  to begin the vehicle acquisition process. Once the vehicle transporter  18  and the lifting platform  26  have been positioned adjacent to the transfer room  12 , the dolly  30  will be deployed from the lifting platform  26 . 
         [0082]    Because the dimensions and position of the vehicle  14  have already been measured, the dolly  30  may be pre-adjusted to accommodate the size of the vehicle  14 , and, if necessary, non-ideal positioning of the vehicle  14  within the transfer room  12 . Specifically, because the wheelbase of the vehicle  14  has been measured or determined prior to deployment of the dolly  30 , the separation of the slidable sections  32  and  34  may be set before or as the dolly  30  is deployed. Similarly, because the placement of the vehicle  14  is known, it may be possible, through an adjustment of the position of the vehicle transporter  18  and/or by rotating the dolly  30  through the use of the rotary table  28 , to accommodate a vehicle  14  which is skewed in relation to the transfer room  12 . Furthermore, this flexibility may remove the need for structures within the transfer room  12  such as tire guides or the like. 
         [0083]    Once the dolly  30  has been deployed under the vehicle  14 , as previously described, the arms  66  are deployed and engage and lift the wheels of the vehicle  14 . With the vehicle  14  lifted from the floor of the vehicle transfer room  12 , the dolly  30  returns to the lifting platform  26  with the vehicle  14 . Once the vehicle  14  has been transferred to the lifting platform  26 , the vehicle transporter  18  may move laterally and/or the lifting platform  26  may move vertically such that the vehicle  14  may be positioned adjacent to an empty parking space  16 . Once the lifting platform  26  is adjacent to a parking space  16  in which the vehicle  14  is to be parked, an alignment device (not shown) may be deployed to ensure that the lifting platform  26  remains relatively motionless and adjacent to the desired parking space  16  when the vehicle  14  is offloaded. The alignment device may take a number of forms however, a ramp or one or more arms which extend from the lifting platform  26  and which includes one or more engagement points capable of engaging reciprocal points adjacent to the parking space  16  is preferred. If necessary, in one embodiment, either the dolly  30  or the lifting platform  26  may be tilted such that it departs from the horizontal at an angle which approximates the angle of slope of the floor  17  of the parking space  16 . To park the vehicle  14 , the dolly  30 , carrying the vehicle  14  is deployed from the lifting platform  26  and into the parking space  16 . The vehicle  14  is lowered and the arms  66  are disengaged from the wheels of the vehicle  14 . The dolly  30  is then retracted to the lifting platform  26 . In a preferred embodiment, the dolly  30  is deployable from either side of the lifting platform  26 . However, note that prior to parking the vehicle  14 , the rotary table  28  may be used to rotate the dolly  30  such that the dolly  30  need deploy from only one direction relative to the rotary table  28 . 
         [0084]    To retrieve a vehicle  14  from a parking space  16 , the process is reversed. In a preferred embodiment, the vehicle  14  is rotated at some point in the parking process such that the vehicle operator may drive the vehicle  14  in and out of the vehicle transfer room  12  without having to back in or out. 
         [0085]    Turning to  FIG. 16 , a flowchart detailing the steps of a parking structure mapping operation are detailed. In step  1000 , an initial, or set up step may be performed. In this step, an operator may enter data into the parking management system  21  representing physical characteristics of the parking structure  10  and/or the vehicle transporter(s)  18 . Such data could include, but not be limited to, information regarding physical dimensions of the parking spaces  16  and transfer rooms  12  in the parking structure  10 , such as length, width, height and location of the parking spaces  16  and the transfer rooms  12 . Furthermore, data representing characteristics of the vehicle transporter(s) such as, but not limited to, location, rate of travel and the like, may be entered. Additional information regarding, for example, locations of end zones, obstructions, and fire suppression areas may also be entered. 
         [0086]    In step  1010 , a verification step may be performed. In this step, which may either be ordered by an operator or may occur automatically in the operation of the vehicle parking apparatus, the vehicle transporter(s)  18  are directed to a known location within the parking structure  10  associated with at least some of the data entered in step  1000  to verify the accuracy of the data entered in step  1000 . Once the vehicle transporter(s)  18  arrive at the known location, the vehicle transporter attempts to engage or identify an indexing marker located at the known location. The indexing marker, which may comprise a beacon, transponder, reflector or the like, allows the parking management system  21  to identify an actual location within parking structure  10 . In step  1020 , the parking management system  21  compares the expected location of the indexing marker, L EXPECTED  which may have been entered in the set up step  1000  against the actual location of the indexing marker L ACTUAL  identified in step  1010 . 
         [0087]    If L EXPECTED  agrees with L ACTUAL , the process moves to step  1030  where the operation being carried out by the parking management system is continued. Such operation could be the verification step  1010  previously discussed, or, the operation may be vehicle-moving operation, in which case the parking management system  21  will perform the parking or retrieving operation as expected. 
         [0088]    If however, L EXPECTED  does not agree with L ACTUAL , the process moves to step  1040  where the parking management system  21  may alter L EXPECTED  to agree with L ACTUAL , Following the alteration to L EXPECTED , the process moves to step  1030  and the current operation is completed. 
         [0089]    In step  1040 , the parking management system  21  determines if additional operations requiring verification are needed. Such determination could be a self check of requested operations contained within the parking management system&#39;s  21  operation buffer, or could be a request for additional instructions from the system operator. In either case, such operations could include additional vehicle-moving operations if additional verification steps are requested in connection with the vehicle-moving operation, or could be additional verification steps if, for example, multiple locations are to be verified by the system. If additional operations are needed, the system returns to the verification step  1010 . If no additional operations are needed, the process ends at step  1050 . 
         [0090]    Although the present invention has been described in terms of certain preferred embodiments, the various examples presented should not be interpreted as limitations on the scope of the present invention. Numerous embodiments and variations are possible which could be substituted without departing from the scope of the present invention.

Summary:
The present invention as disclosed herein is an improved vehicle parking structure and method for using the same. The vehicle parking structure provides for the automated storage and retrieval of vehicles in response to user inputs. In one aspect, the vehicle parking structure comprises one or more transfer rooms in which a vehicle operator may deposit and later retrieve a vehicle, a plurality of parking spaces of either fixed or variable dimensions, and one or more vehicle transporters used to move vehicles from the one or more transfer rooms to the plurality of parking spaces. The one or more vehicle transporters are in turn each preferably comprised of one or more vertical stabilizers, one or more tractors, one or more lifts, a lifting platform, and a dolly. The vehicle transporters move the lifting platform and dolly so that the dolly may be positioned to access a vehicle located in a transfer room or parking space.