Patent Publication Number: US-2010122492-A1

Title: Shutter

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit from U.S. provisional application Ser. No. 61/193,295 filed Nov. 14, 2008 which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to shutters having movable blades or louvers. 
     BACKGROUND OF THE INVENTION 
     The invention has been devised primarily in the context of window shutters that act as sunshades or other forms of weather barrier (e.g. hurricane shutters). At the same time, the invention may be applicable to shutter for other purposes, e.g. controlling air flow in ventilation systems. 
     Shutters that are designed as sunshades for building typically include a blade actuation system by which the angular positions of the blades can be adjusted to provide for controllable solar shading. In sophisticated systems, the shutter may be controlled automatically to provide variable shading in response to varying solar conditions during the day. 
     In commercial applications, the shutters typically are installed on the exterior of the building. As such, the shutters are exposed to wind and other weather conditions that can cause the blades to vibrate. This can lead to problems with noise, poor operation and possible failure. 
     An object of the present invention is to provide an improved shutter that addresses the problem of blade vibration. 
     SUMMARY OF THE INVENTION 
     According to the invention there is provided a shutter comprising a plurality of frame members defining an opening, a plurality of blades extending across the opening between respective frame members that are parallel to one another and means for pivotally coupling each blade at each end to a respective one of the parallel frame members so that each blade is movable between an open position and a closed position with respect to the opening. The coupling means includes, at each end of each blade, a pivot shaft that is received in respective complimentary sleeves in the blade and adjacent frame member respectively. The shaft is split longitudinally into at least two co-extensive shaft elements that are radially movable with respect ton one another to vary the effective diameter of the shaft. Means is provided for effecting such radial movement so that the shaft can be expanded to take up clearance between the shaft and the respective sleeves. 
     In other words, the shaft can effectively be tightened into the respective sleeves to eliminate relative movement and thereby avoid or minimize vibration of the blade when the shutter is in use. The sleeve within the blade typically will be an integral part of the blade structure. For example, the blade may be an extrusion having a wall portion that is shaped to provide the required sleeve. At the other end of the shaft, the sleeve can simply be mounted to turn in the relevant frame member, or the sleeve can be part of an operating system for controlling movement of the blades. 
     Preferably, the shaft is split longitudinally into two shaft elements, each of generally semi-cylindrical shape. Inner faces of the respective shaft elements preferably are contoured in complimentary fashion to provide keyways that prevent lateral displacement of the shaft elements with respect to one another. 
     The shaft may also be “keyed” into the respective sleeves by appropriately contouring the external surface of the shaft and correspondingly contouring the internal surfaces of the sleeves. This will allow the shaft to slide in and out of the respective sleeves, which facilitates assembly of the shutter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which illustrate a particular preferred embodiment of the invention by way of example, and in which: 
         FIG. 1  is a three-quarter perspective view from the front and above of a shutter in accordance with one embodiment of the invention; 
         FIG. 2  is a front elevational view corresponding to  FIG. 1 ; 
         FIG. 3  is a detail perspective view of the part of  FIG. 1  that is circled at A; 
         FIG. 4  is an exploded perspective view of one end of one of the blades of the shutter shown in the previous views; 
         FIG. 5  comprises perspective, plan and end elevational views of a typical blade, denoted respectively (a), (b) and (c); and, 
         FIG. 6  is an exploded perspective view from the rear in  FIG. 1  showing one of the frame members of the shutter, and a blade actuating system incorporated within that frame member. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring first to  FIGS. 1 and 2 , a shutter that is designed to be used as a sunshade is shown by way of example and is generally designated by reference numeral  20 . The shutter includes a pair of upright frame members or mullions  22  that define an opening  24 . A plurality of blades  26  extend across the opening between the mullions and are movable between the closed positions in which they are shown in  FIG. 2  and open positions in which the blades are “edge on” to any air flow through opening  24 . 
     The particular shutter shown in the drawings is intended to be shipped in “knock-down” form and assembled on site at the exterior of a building. As such, the shutter does not have a complete frame as such, the opening  24  is defined by the two mullions  22 . In other embodiments, a complete rectangular frame may be provided. The blades may extend horizontally as shown or vertically between the frame members. 
     At each end of each blade is a pivot shaft  28  by which the blade is mounted to the mullions  22 . 
     Referring now to  FIG. 4 , a typical one of the pivot shafts is shown in an exploded condition and separate from the blade itself. It will be seen that the shaft is split longitudinally into two co-extensive shaft elements. The elements are radially movable with respect to one another to vary the effective diameter of the shaft by means of an adjusting screw  30 . In this way, the shaft can effectively be expanded radially to take up any clearance that might allow the blade to vibrate in use. 
     As seen in  FIG. 4 , shaft  28  includes upper and lower shaft halves each of generally semi-cylindrical shape. The halves are shown in exploded positions for clarity of illustration. In use, the parts fit together with their respective inner faces  32   a,    34   a  in contact so that the shaft can fit into a complimentary sleeve  36  within the blade. A corresponding sleeve (not shown) is provided within the adjacent mullion  22  but is not shown in  FIG. 4 . It will be seen that the respective inner faces  32   a,    34   a  are contoured in complimentary fashion to define keyways that prevent lateral displacement of the shaft halves with respect to one another, e.g. during assembly of the shutter. The external surfaces of the shaft halves are also longitudinally grooved and the internal surface of the sleeve  36  is provided with complimentary protrusions so that the shaft is also keyed to the sleeve and hence to the blade  26 , i.e. can slide longitudinally with respect to the sleeve and blade but cannot be turned with respect to the sleeve and blade. 
     In the illustrated embodiment, the blades are extrusions and the walls of the extrusion are shaped to define the sleeve  36  (as well as other contour elements required in the blade). These include respective channels  38  above and below sleeve  36  for receiving a plate  40  that carries the shaft adjusting screw  30 . Plate  40  is longitudinally slideable in channel  38  so that the adjusting screw  30  can move in and out with the pivot shaft  28 . A slot  42  in the blade accommodates the screw and the plate  40  serves to cover the slot when the blade is in its assembled condition. Two channels  38  are provided so that plate  40  can be installed at either side of the blade, though normally there will be only one plate and one adjustment screw. 
     The adjustment screw  30  extends through a complimentarily screw-threaded opening  42  in the upper shaft half  32  and the distal end of the screw bears against a seat  44  on the lower shaft half  34 . Thus, by turning the screw  30  in the appropriate direction, the two shaft halves  32 ,  34  are moved apart as the upper shaft half moves up the screw and the screw presses down on the lower shaft half  34 . The opening  42  is disposed generally at the centre of the length of the pivot shaft so that the two shaft halves remain substantially parallel to one another as they are adjusted in the radial direction of the shaft. 
     The pivot shafts that are at the right hand ends of the respective blades as shown in  FIGS. 1 and 2  are received in respective sleeves  46  that are mounted to turn freely in the mullion  22 . As such, these sleeves will merely oscillate angularly back and forth as the blades move between their open and closed positions. Sleeves  46  have plain cylindrical exterior surfaces and contoured interior surfaces that are essentially the same as the interior surface of sleeve  36  shown in  FIG. 4 . 
     The mullion that is shown at the left hand side of the shutter in  FIG. 1  supports respective sleeves that are similar to the sleeves  46  but that form part of a blade actuator system shown in an exploded configuration in  FIG. 6 . The sleeves are indicated at  48  and are mounted to turn in corresponding openings  50  in a vertical channel  52  of mullion  22 . The sleeves have reduced diameter portions  48   a  at respectively opposite ends that are actually received in the openings  50  in channel  52  when the shutter is assembled. The pivot shafts  28  then extend into the respective sleeves through openings  50 . 
     Each sleeve  48  has a radial arm  54  pivotally coupled to a vertical actuator rail  56  that effectively couples together all of the sleeves and, accordingly, all of the blades  26  of the shutter. One of the sleeves (in this case the second from the top) has a second radial arm  58  that is diametrally opposed to the first arm  54  and that extends through an opening (not shown) in mullion channel  52  and into a second channel  60  of the mullion. Channel  60  houses a blade actuator in the form of an electric servo motor and gearbox assembly  62 . Assembly  62  includes a rod  64  that moves up and down when the motor is operated and which is pivotally coupled at its upper end to the sleeve arm  58  mentioned previously. Accordingly, the shutter blades  26  move together through the same angular amount upon operation of actuator assembly  62 . 
     As mentioned previously, the sleeves  48  are internally profiled in the same way as the sleeves  36  so that the pivot shafts  28  are keyed to the respective sleeves and can move longitudinally with respect to the sleeve, but not radially. This feature allows the shutter to be assembled by first sliding the respective pivot shafts fully into the sleeves  36  in the blades (so that the pivot shafts are retracted), positioning the blades as required, and then extending the pivot shafts into the complimentary sleeves in the mullions of the shutter. Each shaft is then “snugged” into place by turning the relevant adjusting screw  30  to take up clearance between the shaft and the respective sleeves in the blade  26  and in the mullion  22 . This effectively eliminates or at least minimizes vibration of the blade in use. 
     It will of course be appreciated that the preceding description relates to a particular preferred embodiment of the invention and that many modifications are possible, some of which have been indicated above, and others of which will be apparent to a person skilled in the art. Though the preferred embodiment involves the use of two semi-cylindrical shaft elements, it is to be understood that the two shaft elements need not be of the same cross-sectional shape and/or that more than two elements could be used, though probably at the cost of additional complexity. In a basic form of shutter, the shaft elements could even have plain exterior surfaces, i.e. not be keyed into the sleeves or to each other. Further, although the invention has been described in the context of an exterior sunshade for a building, the invention is not limited to this application.