Abstract:
A retractable roof system ( 30 ) for a large building structure ( 32 ) for selectively closing off an opening ( 39 ) of a fixed roof ( 34 ) of the building structure ( 32 ), the system includes at least one roof section ( 40 ) movably mountable on at least one pier ( 42 ) of substantially C-section when viewed in profile. The or each pier ( 42 ) comprises a ground-engaging foot ( 43 ) with an upstanding substantially columnar portion ( 48 ) leading to a substantially horizontal top section ( 50 ) provided with a movable bracket ( 44 ) reciprocable in guide channels ( 54 ) formed in the top section ( 50 ) and actuable by a deployment mechanism ( 46 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to roof support systems for large building structures and is more particularly concerned with a self-supporting pier for a retractable roof system for large building structures such as stadiums and the like and the components thereof. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is well known in the art to build stadiums for major sports events or the like that can receive many thousands of seated spectators. Most of these main sports events or other require an open sky over the sports field, while the grandstands are preferably protected by an over-hanging peripheral roof to protect the spectators from precipitation, e.g. rain, snow, etc. However, in regions with cold temperatures and frequent snowfalls during winter, or even with heavy rains, it would be beneficial to provide a complete covering for the stadium, namely a roof, but such a provision would preclude the holding of certain events thus limiting the scope of use. 
         [0003]    This dilemma has been addressed by the installation of, retractable roof systems at various stadiums. However, these systems are generally very expensive, complex, raise safety issues, and may require time-consuming deployment mechanisms, which may militate against their installation. 
         [0004]    Accordingly, there is a need for an improved self-supporting pier for a retractable roof system for large building structures and improved components used therefor. 
       SUMMARY OF THE INVENTION 
       [0005]    It is therefore a general object of the present invention to provide an improved self-supporting pier for a retractable roof system for large building structures and/or improved components used therefore, which solves the above mentioned problems. 
         [0006]    An advantage of the self-supporting pier of the present invention is that it does not impart vision of the playing field of the stadium by the spectators located in the grandstands since the pier structure shape follows the tapered contour thereof. 
         [0007]    According to a first aspect of the present invention there is provided a retractable roof system for a large building structure for selectively closing off a roof opening of the building structure, said roof system being characterized by:
       a generally planar roof structure for substantially covering the opening;   a deployment mechanism connected to the retractable roof system and allowing translational displacement of said roof system between a deployed position in which said roof system closes off the opening, and a retracted position in which the opening is generally uncovered and said roof system is retracted to a parked position.       
 
         [0010]    The deployment mechanism is adapted to effect translational displacement in a substantially horizontal or in a substantially vertical direction. 
         [0011]    The roof system is drawn across the said opening in a substantially horizontal direction. 
         [0012]    The roof system is elevated in a substantially vertical direction into a closure position in relation to said opening. 
         [0013]    In an alternative embodiment, the translational displacement may be effected in an angular orientation between horizontal and vertical. 
         [0014]    According to another aspect of the present invention, there is provided a retractable roof system for a large building structure for selectively closing off an opening of a fixed roof of the building structure, said retractable roof system comprising:
       a generally planar roof structure for substantially covering the opening and having at least one roof section;   at least one self-supporting structural pier for supporting a corresponding roof section; and   a deployment mechanism connecting each said roof section to a corresponding said pier, said deployment mechanism allowing translational displacement of each said roof section between a deployed position in which said roof section closes off a portion of the opening, and a retracted position in which the opening is generally uncovered and said roof section is generally located in vertical alignment with at least a portion of the fixed roof.       
 
         [0018]    Conveniently, the roof structure has at least two complementary roof sections each roof section being supported by a respective pier. 
         [0019]    Each roof section may be arranged to slide over or under the fixed roof when being deployed, the extent of the roof section and of the fixed roof being substantially coincident when the roof section is in the retracted position. 
         [0020]    According to a further aspect of the present invention there is provided a retractable roof system for a large building structure for selectively closing off an opening of a fixed roof of the building structure, said retractable roof system comprising:
       a generally planar roof structure for substantially covering the opening; and having at least one roof section;   at least one self-supporting structural pier for supporting a corresponding roof section;   the self-supporting structural pier being of substantial C-shape in side profile and comprising a ground engaging substantially horizontal foot, an intermediate substantially vertical section solid with said foot, a substantially horizontal top section extending from the said vertical section in cantilever, and a roof connecting part provided on said top section movably supporting corresponding said roof section; and   a deployment mechanism connecting each said roof section to the roof connecting part of the substantially horizontal top section of the corresponding said pier, said deployment mechanism allowing translational displacement of each said roof section between a deployed position in which said roof section closes off a portion of the opening, and a retracted position in which the opening is generally uncovered and said roof section is generally located in vertical alignment with at least a portion of the fixed roof.       
 
         [0025]    Conveniently the roof connecting part of the substantially horizontal top section is provided with a leading portion of stepped form for supporting a margin of the respective roof section. Said roof connecting part of the top section of the pier is in the form of a bracket reciprocally movable in relation to the top section of its respective pier. 
         [0026]    The or each pier may be similar or identical in shape and dimension as the supporting structure(s) of the large building. For example, the piers may be of like form as the supporting structures, e.g. columns, of the building and in some embodiments may be disposed in close adjacency thereto. Such embodiments are appropriate for retrofit applications to existing buildings. In an alternative embodiment the piers and the supporting structures may be one and the same whereby the deployment mechanism is mounted on the supporting structure of the building and this design would be beneficial for a new building. 
         [0027]    It will be understood that in the case where the piers and the supporting structures are one and the same, the C-shape is maintained as an appropriate and strong constructional feature. 
         [0028]    Conveniently, the ground engaging substantially horizontal foot of the pier substantially tapers upwardly toward the intermediate vertical section so as to generally follow a contour of the grandstand of the building structure adjacent said corresponding pier. 
         [0029]    The fixed roof surmounts the pier with the roof section of the roof system being arranged to slide over or under the fixed roof. 
         [0030]    The deployment mechanism may conveniently be a system of ropes, pulleys and an actuating element adapted to effect anchoring of the roof section(s) in its respective positions. Each roof section may be provided with a respective deployment mechanism if desired, but one deployment mechanism may be employed acting in tandem on the roof sections of the retractable roof system. 
         [0031]    Conveniently the actuating element is fluid operable either to release the roof sections from them from the open position or to effect closure thereof. 
         [0032]    The fluid operable element may comprise at least one cylinder in which there is slidably disposed a weight in the form of a piston on which a fluid is operable. Advantageously the piston is of such dimension as to require a relatively low pressure fluid to effect the requisite movement for the roof section to move, the application of fluid pressure or its removal occasioning the necessary movement. The fluid may be compressed air or other suitable gas. 
         [0033]    The movable part of the leading portion of the top substantially horizontal section of the pier is in the form of a bracket carrying rollers slidable within a guide channel formed on the top section at either side thereof. The ropes of the deployment system being connected to the roof connecting part of the top section. 
         [0034]    At the junction of the two roof sections of the retractable roof structure there is provided a system of panels which serve to bridge the junction thereby to close off the area beneath the whole of the roof. The system of panels is operated by a winch arrangement including a rope array reeved over wheels provided for this purpose, the panels being provided with rollers engaging the marginal regions of the roof sections which are formed thereat with complementary channels for the rollers. A suitable drive arrangement is provided for energizing the panel system to run either to engage or disengage the said marginal regions of the roof sections. The drive arrangement may be of a similar kind as that of the deployment mechanism hereinbefore described. 
         [0035]    According to a further aspect of the present invention, there is provided a self-supporting pier for a retractable roof system comprising a substantially C-shape in side profile and comprising a ground engaging substantially horizontal foot, an intermediate substantially vertical section solid with said foot, a substantially horizontal top section extending from the said vertical section in cantilever, and a roof connecting part provided on said top section movably supporting corresponding said roof section. 
         [0036]    Other objects and advantages of the present invention will become apparent from a careful reading of the detailed description provided herein, with appropriate reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    Further aspects and advantages of the present invention will become better understood with reference to the description in association with the following Figures, in which similar references used in different Figures denote similar components, wherein: 
           [0038]      FIG. 1  is a top perspective view of a typical large building structure with a retractable roof system in accordance with an embodiment of the present invention; 
           [0039]      FIGS. 2 to 4  are partially broken top plan, side elevational, and rear elevational views of the embodiment of  FIG. 1 , with the roof section in closed position; 
           [0040]      FIG. 5  is a partially broken top perspective view of the embodiment of  FIG. 1 , with the roof section in closed position; 
           [0041]      FIG. 6  is a partially broken top plan view of the embodiment of  FIG. 1 , with the roof section in closed position; 
           [0042]      FIGS. 7 and 8  are partially broken section views of the embodiment of  FIG. 1 , with the roof section in closed and retracted positions, respectively; 
           [0043]      FIGS. 9 to 12  are different partially broken views of the embodiment of  FIG. 1 , with the roof section in retracted position; 
           [0044]      FIG. 13  is an enlarged partially broken top plan view of the embodiment of  FIG. 1 , with the roof section in retracted position; 
           [0045]      FIG. 14  is an enlarged partially broken top perspective view of the embodiment of  FIG. 1 , with the roof section in retracted position, and showing a portion of the roof deployment mechanism; 
           [0046]      FIG. 15   a  is a perspective view of an embodiment of a weight piston; 
           [0047]      FIG. 15   b  is a top plan view of the piston of  FIG. 15   a;    
           [0048]      FIG. 15   c  is an enlarged fragmentary view taken along line  15   c  of  FIG. 15   a;    
           [0049]      FIG. 15   d  is a longitudinal sectional view on the line  15   d - 15   d  of  FIG. 15   b;    
           [0050]      FIG. 15   e  is an enlarged fragmentary detailed view taken along line  15   e  of  FIG. 15   d;    
           [0051]      FIG. 16  is a perspective view of the embodiment of  FIG. 15   a  sectioned on the line  15   d - 15   d  of  FIG. 15   b;    
           [0052]      FIGS. 17 to 19  are different partially broken views of the embodiment of  FIG. 1  of the intermediate support structure connecting the roof sections in closed position; 
           [0053]      FIG. 20  is a partially broken top perspective view of the embodiment of  FIG. 1  of the intermediate support structure displaced away from the roof opening, with the roof section in retracted position; 
           [0054]      FIG. 21  is a partially broken side elevational view of the embodiment of  FIG. 1 , showing details of the synchronization mechanism, with the roof section in closed position; 
           [0055]      FIGS. 21   a  and  21   b  are enlarged fragmentary detailed views taken along line  21   a  and line  21   b  of  FIG. 21 , respectively; 
           [0056]      FIG. 22  is a partially broken side elevational view of the embodiment of  FIG. 1 , showing details of the synchronization mechanism, with the roof sections in retracted position; and 
           [0057]      FIGS. 22   a  and  22   b  are enlarged fragmentary detailed views taken along line  22   a  and line  22   b  of  FIG. 22 , respectively. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0058]    With reference to the annexed drawings, in most of which many parts have voluntarily been omitted for clarity purposes (especially when the intermediate support structure is shown across the opening while the roof sections are retracted, which is not an actual configuration), the preferred embodiments of the present invention will be herein described for indicative purpose and by no means as of limitation. 
         [0059]    Referring to  FIGS. 1 to 4 , there is schematically shown an embodiment  30  of a retractable roof system for large building structures such as stadiums  32  and the like in accordance with the present invention, as well as the different innovative components of the system. Although some components may more specifically be usable with the presence of predetermined portions of the structure, some others are applicable to most structures. As illustrated throughout the Figures, the present invention is illustrated on the Olympic Stadium™  32  of Montreal, Canada known for having an inclined tower  33  for the support of an original retractable cover membrane (not shown) using a plurality of wire cables (not shown). 
         [0060]    The stadium  32  typically includes grandstand fixed roof  34  including a plurality of cantilevers  36  and running around the sport field  37  (see  FIGS. 5 and 11 ) and defining an inner periphery  38  thereof itself defining a roof opening  39 . Although not shown, the inner periphery could be defined by walls or even wall/roof structures. The retractable roof  30  of the present invention includes at least one, preferably two roof sections  40  of a generally planar roof structure that substantially cover the opening  39 . Each roof section  40  is supported by at least one, preferably two self-supporting generally monolithic piers  42 . A typical embodiment of each pier  42  is connected to the roof section  40  via a roof connecting part in the form of a roof support bracket  44  movably mounted on the pier  42 , for displacement of the support bracket  44 , and the roof section  40 , relative to the pier  42 . A typical embodiment of a roof deployment mechanism  46  (better seen in  FIG. 14 ) connected to the support bracket  44  activates the displacement of the roof section  40  between a closed or deployed position in which the roof section  40  covers a respective portion of the opening  39 , as shown in  FIGS. 1 to 7 , and an open or undeployed or retracted position in which the respective portion of the opening  39  is uncovered by the roof section  40 , as shown in  FIGS. 8 to 14 . In the retracted position, each roof section  40  is preferably completely overlaid by a portion of the fixed roof  34  but could also be located above the existing roof structure  34 , or simply at least partially over an uncovered grandstand  45  (schematically shown in dotted lines in  FIG. 8 ), or outside a stadium outer periphery without departing from the scope of the present invention. Although the present piers  42  are substantially structurally independent from the structure  36  of the stadium, they could eventually be part of that structure if required or desired. The piers  42  typically support the respective roof section  40  along a roof support axis passing by the center of gravity  41  of the section, when in the closed position. 
         [0061]    Each pier  42  is a structure that surrounds and embraces an existing cantilever  36  of the stadium  32  (without structurally connecting thereto), and includes a foot  43  with a generally vertical column section  48  upstanding therefrom and supporting a generally horizontal top beam section  50  along which the respective support bracket  44  is displaced via rollers  52  engaging a sloping guide channel  54  expending along the beam section  50 . As better seen in  FIG. 7 , the guide channel  54  slopes downwardly toward the column section  48  such that the support bracket  44  is maintained in the top end  56  of the guide channel  54  to have the roof section  40  in the closed position. To open the roof section  40 , the support bracket  44  is controllably released from the top end  56  of the guide channel  54  toward the bottom end  58  by gravitational force. 
         [0062]    Typically, the foot  43  of each pier  42  substantially tapers upwardly toward the intermediate vertical section  48  to generally follow a contour of the adjacent grandstand  45  of the building structure  32 , as shown in  FIG. 8 . 
         [0063]    As better seen in  FIG. 14 , each support bracket  44  is connected to a deployment mechanism  46  typically including a weight  60  in the form of a piston slidably and sealably moving along a generally vertical hollow cylinder  62  preferably located underground. The upper end  64  of the weight  60  is connected to preferably all of the support brackets  44  respectively via the agency of a plurality of wire cables  66  or ropes and associated pulleys  68 . The weight  60  has a sufficient mass to simultaneously maintain all the roof sections  40  in the closed position, with the respective support bracket  44  in the top end  56  of the guide channel  54 . To controllably release the support brackets  44  and open the roof  40 , a pressurized gas is controllably injected into a closed volume of the cylinder  62  below the weight  60  and defining a pressurized chamber  70 , using an appropriate valve system  72  to in effect push on and controllably raise the weight  60 . As long as the pressure is maintained within the cylinder  62  below the weight  60 , the roof  40  remains open. The close the roof  40  back, the pressure is slowly released from the pressurized chamber  70 . 
         [0064]    Although shown centrally located relative to the four piers  42  and their support brackets  44 , the cylinder  62  can obviously be located anywhere. One skilled in the art would readily understand that although one corresponding cylinder/piston weight assembly could be used for each support bracket or for all support brackets of each roof section without departing from the scope of the present invention, it is preferable to simultaneously control all support brackets and roof sections on a common system. 
         [0065]    The actual shape of the guide channel  54  is dictated by the shape of the roof section  40 . The higher the slope of the top surface of the roof section  40 , the higher the slope of the guide channel  54  to allow the roof section  40  to clear the inner periphery  38  of the fixed roof  34 . 
         [0066]    In order to allow the peripheral edges roof sections  40  to be essentially in register with the inner periphery  38  of the fixed roof  34 , the roof sections  40  need to be generally vertically lowered before the actual opening may start. To this effect, as better seen in  FIGS. 7 and 17 , a pneumatic, hydraulic, electric, or the like deployed raising mechanism  74  is located between each support bracket  44  and the roof section  40 . When a roof section  40  is supported by a plurality of brackets  44 /piers  42 , all the deployed raising mechanisms  74  of a same roof section  40  are obviously synchronized. 
         [0067]    When the roof sections  40  are in the closed position, they remain slightly spaced from the fixed roof  34 , and the gap there between would typically be covered by an outwardly extendable gutter (not shown) mounted onto the fixed roof  34 , in order to completely close off the roof opening  39 . 
       Weight Assembly 
       [0068]    As, shown in  FIGS. 15   a  to  15   e  and  16 , the typical embodiment of a weight assembly in the form of a piston  60  typically has an elongated cylindrical body  76  having top and bottom ring-type cylinder bumpers  78 , typically made out of wear resistant type plastic type material to ensure smooth axial displacement thereof along and inside the cylinder  62 . The cylinder bumpers  78  are typically tight fit with the cylinder  62 , and to this end, at least the upper bumper  78 , which is longitudinally opposite the seal assembly  82 , is radially outwardly biased to abut against the cylinder using a typical O-ring  80  or the like. On the other hand, to ensure a proper seal between the weight  60  and the cylinder  62  without jeopardizing the relative movement there between, the weight  60  includes a seal assembly  82 , preferably located adjacent the bottom end thereof. The seal assembly  82  includes two side-by-side seal rings  84 , typically made out of a polyimide type material or the like, preferably having their ring slots  86  angularly spaced from one another, typically at least 90 degrees, and preferably 180 degrees. Furthermore, the two seal rings  84  are typically biased radially outwardly towards the cylinder  62  by a compressed inner seal ring  88 , typically made out of a rubber type material or the like. The inner seal ring  88  typically fills in the entire space between the two seal rings  84  and the piston body  76 . 
       Intermediate Support Structure 
       [0069]    As better seen in a section view taken along a vertical plane passing in between the two roof sections  40 , as in  FIGS. 17 ,  18  and  19 , an embodiment of removable intermediate support structure  90  includes a longitudinally articulated structure releasably connecting to both roof sections  40  (when in closed position) and supported by angled wire cables  92  running adjacent to a top end of the stadium tower  33 . The intermediate support structure  90 , adapted to close off a longitudinal gap between the two roof sections  40  when in closed position, typically includes a plurality of wheeled panels  94  (only frame structure shown in  FIGS. 17 to 20 ) hingeably connected to the adjacent panels  94  into an end-to-end configuration (as cars in a train), and having side wheels  96  rollably engaging respective guide channels  98  extending along the roof sections  40 . A plurality of panels  94 , typically four, are each supported by a pair of wire cables  92 , one connected adjacent each roof section  40  (as seen in  FIGS. 3 and 17 ), the pairs of wire cables  92  are respectively angled at the vertical and successively at about 27, 46 and 56 degrees from the vertical). Each wire cable  92  of each pair has one end connected to the respective wheeled panel  94 , passes around a first channeled wheel (not shown) freely rotatably mounted at the top of the tower  33  and the around successive channeled wheels (not shown) adjacent the opening periphery  38 , and others, up to the other end connected to the tensioning mechanism (not shown) of any type and even another weight piston/cylinder assembly or the like. Although not illustrated, the two wire cables  92  of a same pair could be extending from one another as to form a single wire cable that would ensure a same tension on both sides of the respective wheeled panel  94  connected thereto. 
         [0070]    The train panel structure  90  is adapted to be rollably displaced away form the two roof sections  40  into a storage channel (as illustrated in  FIG. 21 ) to free up the two roof sections  40  and allowing them to be displaced into their retracted position. Here again, different type of driving mechanisms (not shown) could be considered, such as another weight piston/cylinder assembly or the like, depending on the needs. 
         [0071]    Alternatively, the intermediate support structure  90  could be a more simple closing and releasably securing mechanism located between the two roof sections and mounted thereon (not shown). 
       Synchronization Mechanism 
       [0072]    In the present case, as better seen in  FIGS. 2 ,  6 ,  10 , and  13 , since each pier  42  orientation is angled relative to the translation displacement direction  100  of the corresponding roof section  40  between the deployed and retracted positions, the angled displacement direction of each support bracket  44  forces the attachment point  102  of the respective support bracket  44  to the roof section  40  to translate relative to the center of gravity  41  of the roof section  40  perpendicularly to the translation displacement  100  of the roof section  40 . 
         [0073]    Accordingly, to ensure that each roof section  40  does not get displaced sideways relative to its normal rectilinear translation displacement direction  100 , since both piers  42  are similarly angled in opposite directions relative to the roof translation direction  100 , a typical embodiment of a synchronization mechanism  104  ensures a simultaneous opposite longitudinal displacement of the two support brackets  44  relative to the roof section  40 , as shown in  FIGS. 21 and 22 . 
         [0074]    As shown in closed position in  FIGS. 17 ,  21 ,  21   a  and  21   b  and in retracted position in  FIGS. 22 ,  22   a  and  22   b , the synchronization mechanism  104  includes a rack  106 ,  106 ′ in the form of a plurality of successive bearing blocs  108 ,  108 ′ mounted on a beam guide  110 ,  110 ′ connecting to a respective support bracket  44  and meshing with a respective pinion  112 ,  112 ′ in the form of a freely rotating screw mounted onto the roof structure  40 . To ensure the synchronization, both screws  112 ,  112 ′ are freely rotating about a common shaft  114 , and to ensure the opposite displacements, the two screws  112 ,  112 ′ have opposite thread pitches (one  112  has a left thread, and the other  112 ′ a right thread). The bearing blocks  108 ,  108 ′ are adapted to engage both sides of a same thread to accommodate for displacements in both directions, for closing and retracting of the roof sections  40 . 
         [0075]    Although two roof sections  40  are described and shown herein, it would be obvious the each pier  42  could have supported its own roof section  40  that would have had substantially a quarter of the overall roof size, and similarly for any other number of roof sections and/or piers. 
         [0076]    Although the present invention has been described with a certain degree of particularity, it is to be understood that the disclosure has been made by way of example only and that the present invention is not limited to the features of the embodiments described and illustrated herein, but includes all variations and modifications within the scope and spirit of the invention as hereinafter claimed.