A drum for a roll-up closure, the closure having a door of hinged together slats, one end of the door adapted to be mounted on the drum, the door adapted to be wound on the drum as the drum is rotated. The drum has a wall defining its shape with a depression in the wall extending both inwardly and across the width of the drum. The cross-section of the wall defines an increasing spiral from one side of the depression to the other side of the depression. An extension of the wall extends from the one side of the depression towards the other side to partially close the depression. The partially closed depression is shaped to receive the one end of the door to mount the door on the drum.

RELATED APPLICATIONS 
       [0001]    This application is a divisional application of application Ser. No. 12/386,553, filed Apr. 20, 2009. This application is hereby incorporated inthis application by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    This invention is directed toward improvements in roll-up closures. This invention is more particularly directed toward a tensioning unit for tensioning the spring in a roll-up closure. The invention is also more particularly directed toward the drum for carrying the hinged door on the closure. 
         [0004]    2.Background Art 
         [0005]    Roll-up closures are mounted over the opening to be closed by the hinged door of the closure. The closure has an axle which is normally fixedly mounted between end plates fastened to the wall of a building framing the opening. A drum is rotatably mounted on the axle. A hinged door is attached at its top end to the drum and wound up on the drum when the drum is rotated to open the opening. A motor is normally mounted on the axle within the drum to rotate the drum. However the motor could be mounted outside the drum at one end or the drum could also be rotated manually. A tension coil spring is mounted on the axle within the drum with one end of the spring connected to the axle and the other end connected to the drum. The spring is normally initially tensioned when the closure is installed and is further tensioned when the opening is closed by the hinged door, the door unwinding off the drum. The tensioned spring makes it easier for the door to move up when opening the opening. The tension in the spring can be adjusted externally by various known tensioning means. 
         [0006]    The known closures have several disadvantages however. The tensioning means employed to adjust the tension in the spring is often mounted outside the end plates making it difficult to employ the closure in tight places. The tensioning means also are quite complicated to use, some requiring two people, some requiring a precarious perch on a ladder. The drum normally employed is cylindrical making it difficult to smoothly roll the hinged door onto the drum. It is also difficult to position and mount elements, such as the drive motor, within the drum. 
       SUMMARY OF THE INVENTION 
       [0007]    It is the purpose of the present invention to provide a roll-up closure having an improved tensioning unit. The tensioning unit is simple in construction and quite compact and can be mounted within the end plates allowing the closure to be installed in tight places. The unit is also quite easy to assemble and can be easily and safely used by one person on the ground. It is another purpose of the present invention to provide a drum for a roll-up closure which easily and securely allows the hinged door of the closure to be connected to it; which more evenly wraps the hinged door thereon; and which makes it easier to mount elements within the drum. 
         [0008]    In accordance with the present invention there is provided a tensioning unit comprising a ratchet wheel fixedly mounted on the axle, the axle normally rotatable on the end plates. The ratchet wheel is adjacent one of the end plates and a stop member, slidably mounted on the one end plate, cooperates with the ratchet wheel to lock it, and thus the axle, against rotation in a direction that reduces tension in the spring. A lever is movably mounted on the axle between the ratchet wheel and the end plate. The lever is movable radially to allow it to selectively connect with the ratchet wheel and is also rotatable on the axle to allow it to rotate the wheel in one direction when connected to it. Rotation of the ratchet wheel in the one direction will rotate the axle and thus the one end of the spring to tighten it. The stop allows the wheel to rotate in the tightening direction but prevents the wheel and axle from rotating in the opposite direction to loosen the spring and reduce tension when the lever is disconnected from the wheel. 
         [0009]    Also in accordance with the present invention there is provided a drum for the closure comprising an extruded tube with a mounting for the one end of the hinged door on its surface. The mounting comprises a shallow depression in the wall, formed from the outside of the drum, the depression extending across the width of the drum parallel to its longitudinal axis. The depression has a hook-shaped end to snugly receive the male hinge element on the free side of the first slat in the hinged door. The mounting includes a support surface for part of the first slat adjacent the male hinge element, the surface extending tangentially from the depression. The tube, seen in cross-section, has the wall generally follow a spiral curve from the support surface on one side of the depression to the other side of the depression, the radial distance of the wall from the center of the tube gradually increasing the farther away from the support surface that you go. The shape makes it easier to wind the door thereon. The tube also has extruded channels on its inner surface, extending across the tube parallel to the longitudinal axis of the tube, to help slidingly mount elements within the tube. The channels make it easier to longitudinally position the elements within the tube while preventing them from rotating within the tube. 
         [0010]    The invention is particularly directed toward a spring tensioning unit for a roll-up closure. The closure has a pair of end plates; an axle rotatably mounted between and on the end plates; a drum for carrying a closure, the drum rotatably mounted on the axle; and a tensioning coil spring mounted on the axle and connected between the axle and the drum. The tensioning unit has a ratchet wheel fixedly mounted on the axle adjacent one end plate, the wheel having spaced-apart teeth on its periphery. A stop member is slidably mounted on the one end plate with a stop tab cooperating with the teeth on the wheel to stop movement of the wheel in a direction reducing tension on the spring. A lever is mounted between the wheel and the end plate, the lever having a lever tab for cooperating with the wheel. The lever is movable on the axle both radially and rotationaly to position the lever tab against a tooth and to then rotate the tooth, and the axle, in a direction to increase tension on the spring. 
         [0011]    The invention is also directed toward a hollow drum for a roll-up closure that is extruded and which has at least two apart channels on the inner surface of its wall opening radially inwardly, the channels slidably receivng elements to be mounted within the drum while preventing their rotation. 
         [0012]    The invention is further directed toward a hollow, extruded, drum for a roll-up closure. The drum has a shallow depression formed in the wall, the depression extending inwardly and extending across the width of the drum. There is an overhang extending partway over the depression from one side of the depression, the one side of the depression being curved to match the curve of one side of a male hinge member on one side of a slat of a door to be wound on the drum. The overhang and the curved side imitate the curved open side of the female hinge member on the other side of the slat. 
     
    
     
       DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         [0013]      FIG. 1  is a partial front view, in partial section, of a roll-up closure; 
           [0014]      FIG. 2  is a perspective view of an end plate; 
           [0015]      FIG. 3  is a detail front view of the tensioning unit; 
           [0016]      FIG. 4  is a perspective view of the tensioning unit; 
           [0017]      FIG. 5  is a detail front view of the ratchet wheel; 
           [0018]      FIG. 6  is a perspective view of the stop; 
           [0019]      FIG. 7  is a front view of the lever; 
           [0020]      FIG. 8  is a cross-section view of the tube. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The rolling closure  1 , as shown in  FIGS. 1 and 2 , includes a hinged door  3  made from a plurality of hinged slats  5  wound on a drum  7  rotatably mounted an axle  9 . The closure  1  is mounted at the top of an opening  11  in a wall  13 . Side frames  15  are mounted on each side of the opening  11  on the wall  13  and an end plate  17  is mounted on top of each frame  15 . The end plate  17  is offset, as shown at  18  in  FIG. 2 , to have a portion  19  spaced a short distance from the side of the opening. The axle  9  is rotatably mounted in slots  20  in the off set portion  19  of the end plates  17  to extend between the plates. A guide  21  on top of each frame  15  guides the side  23  of the hinged door  3  into an inside groove  25  running the length of the frame  15 . 
         [0022]    To control the movement of the door  3  a tension coil spring  27  is normally mounted over the axle  9  within the drum  7  with one end  29  of the spring mounted on the axle  9  and the other end  31  mounted to the drum  7 . The tension of the spring  27  is adjusted during installation so that the spring winds up during movement of the hinged door  3  off the drum  7  to close the opening making it easier to raise the door during opening of the opening  11 . 
         [0023]    A tensioning unit  37  is employed to be able to adjust the tension of the spring  27 . The tensioning unit  37 , as shown in  FIG. 3 , has a ratchet wheel  39  fixedly mounted on the axle  9  adjacent the inside of the end plate  17 . The ratchet wheel  39  has uniformly spaced-apart teeth  41  about its periphery as shown in  FIGS. 4 and 5 . Each tooth  41  has an initial straight surface portion  43  leading from the previous tooth to a curved surface portion  45  moving radially away from the center of the wheel  39  and terminating in a stop edge  47  that extends radially inwardly to the start of the straight surface portion  43  of the next adjacent tooth. There is slot  49  extending into the tooth from the bottom of the stop edge  43 , the bottom of the slot  49  aligned with the straight surface portion  43  of the next tooth. 
         [0024]    The tensioning unit  37  includes a stop member  51 . The end plate  17  mounts a stop member  51  in a vertical, T-shaped, slot  53 , the stop freely movable vertically in the slot  53 . The stop  51 , as shown in  FIG. 6 , has a laterally projecting tab  54  that normally interferes with a stop edge  47  on a tooth  41  on the ratchet wheel  39  when the stop  51  is at the bottom of the slot  53 . The stop tab  54  enters the slot  49  on the tooth  41 . The stop tab  54  prevents the wheel  39 , and thus the axle  9 , from rotating counter clockwise, when viewing the wheel from the drum side, and thus unwinding the spring  27  while it is tensioned. The stop  51  has an upper tab  55  above the stop tab  54 , both tabs joined by a back plate  56 . The tab  55  is shorter than the stop tab  54 . The tabs  54 ,  55  are wider than the stem  57  of the slot  53 , almost as wide as the cross-bar  58  of the slot  53 . Both tabs  54 ,  55  have groves  59 ,  60  in their sides intermediate their ends for receiving the end plate  17  to retain the stop slidably on the end wall. The stop  51  is mounted in the slot  53  by inserting the stop tab  54  through the cross-bar portion  58  of the slot  53  until its grooves  59  are aligned with the end plate  17  and then dropping onto the end plate to slide down the stem  57  of the slot  53 . There is a little play between the grooves  59  and the end plate  17  allowing the stop to be slid down the stem with the upper tab  55  adjacent the outside surface of the end plate  17 . Once the upper tab  55  reaches the cross-bar portion  58 , it is passed through it to align its grooves  60  with the end plate  17  and then the stop  51  is further dropped down to have the end plate  17  running through both tabs  54 ,  55  to retain the stop slidably within the slot  53 . 
         [0025]    The tensioning unit  37  further includes an elongated lever  61 , as shown in  FIG. 7 , mounted loosely on the axle  9  between the ratchet wheel  38  and end plate  17 .The lever  61  is in the form of a narrow plate and has an elongated slot  63  adjacent one end  65  through which the axle  9  passes. The slot  63  allows the lever  61  to rotate about the axle  9  and also to move radially with respect to the axle  9 . The other end  67  of the lever  61  carries a tubular receiver  68 . The lever  61  has a laterally projecting tab  69  bent out from about the middle of the lever intermediate its ends  65 ,  67 . The lever tab  69  is located so it can be abutted against the stop edge  45  of one of the teeth  41  on the ratchet wheel  39  when the lever  61  is manipulated by an operator, and more particularly, so it can enter the slot  49  at the bottom of the stop edge  45 . 
         [0026]    In use, when the spring  27  is to be tensioned, an elongated rod  71 , or the like, is inserted by an operator into the receiver  68  on the lever  61 , the lever normally hanging down from the axle  9 . The rod  71  is used to manipulate the lever  61  on the axle  9  by rotating it and moving it radially so the lever tab  69  carried by it rests in the slot  49  in the stop edge  47  of a selected tooth  41  on the ratchet wheel  39 . The operator then rotates the lever  61  clockwise, as shown by the arrow ‘A’ in  FIG. 4 , about the axle  9  while keeping the tab  69  abutted against the stop edge  47 , and in the slot  49 , to rotate the ratchet wheel clockwise to tighten the spring  27 . As the ratchet wheel  39  rotates, so does the axle  9 , tightening the spring against the inertia of the drum  7  and the hinged door  3  on it. The rotation of the ratchet wheel  39  also causes the stop member  51  to ride up the curved part  45  of the next tooth adjacent to it, as shown by the arrow ‘B’, until the stop  51  reaches and passes the stop edge  47  of the tooth to drop down and locate its stop tab  54  in slot  49  in the stop edge  47   o f the tooth. The stem  57  of the slot  53  is high enough to prevent the top tab  55  from normally reaching the cross-bar  58  as the stop  51  rises. Having the stop tab  54  in the slot  49  prevents the spring  27  from unwinding and allows the operator to disengage the lever  61  from the tooth it initially engaged with and move it back to the next adjacent tooth to repeat the process if needed. 
         [0027]    If the tension in the spring  27  needs to be reduced, the operator can slightly rotate the ratchet wheel  39  with the lever  61  to withdraw the stop tab  54  from the slot  49  in the tooth and then merely push the stop  51  upwardly with another bar to have it clear the stop edge  45 . The operator then releases the lever  61  allowing the ratchet wheel  39  to rotate counter clockwise one tooth while simultaneously releasing the stop  51  to drop to engage the next tooth, to reduce tension in the spring. 
         [0028]    The tensioning unit is compact allowing it to be mounted inside the end plate and still clear of the hinged door. With the unit between the end plates, the closure can be mounted in tight places with at least one of the end plates tight in a wall corner if needed. The unit is easy to use. Only one person is required to tension the spring and the tensioning can be done from the ground. Having the lever  61  located between the end plate and the ratchet wheel causes it to act as a washer reducing wear between the ratchet wheel  39  and the end plate  17 . 
         [0029]    The drum  7  for supporting the closure can be constructed to mount elements such as the motor in if more easily. To this end the drum  7  is extruded with the inner surface  75  of the wall  77  of the drum provided with mounting channels  79  at spaced-apart locations along the length of the drum as shown in  FIG. 8 . Three channels are shown but two or four could be provided. The elements to be mounted within the drum, such as a motor  81 , have projecting tabs  83  about their circumference allowing the element to be slid into the drum with the tabs  83  entering the channels  79  to keep the element from rotating within the drum. The element can be slid into the drum the required distance guided by the channels and then locked in place by one or more screws  85  passed through the wall  77  of the drum into one of the channels  79  and the tab  83  in the channel. 
         [0030]    The drum  7  also has mounting means  91  on the outer surface  93  of the wall  77  for mounting the hinged door thereon more easily. The mounting means  91  has a shallow depression  95  formed in the wall  77  of the drum to receive the male hinge end  97  of the end slat  5 A of the door  3 . The depression  95  extends across the width of the drum. The depression has an overhang  99  on one side  101  to help retain the end  97  of the slat within the depression. The overhang  99  and the side  101  of the depression are shaped to form part of the female hinge end  103  of a slat so as to snugly receive part of the male hinge end  97 . The overhang  99  forms part of a flat section  105  of the wall  77  of the drum that extends generally tangentially away from the depression  95 . The flat section  105  is wide enough to receive about half of the width of the panel portion  107  of the end slat  5 A. The weight of the door hanging down the one side of the drum pulls the male end  97  of the end slat  5 A tight into the depression  95 , the male end  97  held in place by the overhang  99 . The end slat  5 A extends generally tangentially away from the depression  95  with the female hinge end  103  positioned relatively close to the wall  77  of the drum. The door is easily mounted on the drum by merely sliding the male hinge end  97  into the depression under the overhang  99 . 
         [0031]    The wall  77  of the drum leaving the flat section  105  follows a spiral curve moving gradually radially away from the center of the drum as it returns to the other side of the depression  95 . The gradual enlarging of the drum around its periphery allows the hinged door  3  to be smoothly wound about the drum.