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RELATED APPLICATION 
     The present Application is a continuation-in-part of Taiwan Patent Application No. 88221196, filed on Dec. 28, 1999, by Ming Nien entitled STRUCTURAL IMPROVEMENT ON VENETIAN BLINDS, the contents of which are incorporated herein by reference in its entirety. 
     FIELD OF THE INVENTION 
     This invention relates generally to venetian blinds, and more specifically to headers for venetian blinds. 
     BACKGROUND OF THE INVENTION 
     Venetian blinds are age-old fixtures that are attached to a door or window to provide privacy, shade, and decoration. The overall width of venetian blinds is typically roughly equivalent to the width of the window or doorframe to which they are mounted. Unfortunately, doors and windows come in a wide variety of widths. Since the cost associated with manufacturing blinds in every conceivable door and window width is exorbitant, the blinds must be custom trimmed in most cases. 
     Venetian blinds which are manufactured to accommodate wide widows or doors typically incorporate a metal plate in the header to prevent the body of the header from sagging. A problem occurs when attempting to trim such a header because devices and methods which are effective for cutting the metal plate are not effective for cutting the body of the header. A die and punching tool works most effectively to produce a smooth surface upon trimming the metal plate, while conventional saw blades tend to produce an unfinished jagged edge in the metal. A disadvantage with using die and punching tools is that a separate die is needed for each differently sized header. This results in a much greater expense if headers having various cross-sectional heights and widths are going to be trimmed. Also, the dies must precisely fit the header in order to avoid an uneven finish or chipping of the header. Additionally, dies can bend and crimp parts of the header made of plastic or other less rigid materials. 
     Another problem encountered when cutting headers is that the header is often broken or damaged during the cutting process. This occurs because the header of prior art blinds are typically U-shaped and the two side panels are not provided with adequate lateral support to withstand forces associated with cutting. 
     Accordingly, there is a need for venetian blinds which incorporate a support as part of the header to allow the blinds to span relatively wide window or door frames without sagging, but which can be effectively and efficiently reduced by cutting with a blade. There is also a need for venetian blinds that have a header that is better suited to being cut without incurring damage. 
     SUMMARY 
     The invention is directed to venetian blinds the satisfy this need. The venetian blinds have a headrail and a slat-structure depending downwardly therefrom. The headrail includes an elongate cover made from a first material. The elongate cover has a longitudinal axis and a pair of opposed ends. The headrail also includes an elongate support member having a longitudinal axis and a pair of opposed ends. The elongate support member is made from a second material and is attached coaxially to the elongate cover so as to provide the elongate cover with increased rigidity. The length of the elongate support member along its longitudinal axis is less than the length of the elongate cover along its longitudinal axis so that the opposed ends of the elongate cover extend distally beyond the opposed ends of the elongate support member, whereby the length of the outer cover material can be reduced by cutting off a portion of at least one of its two ends normal to its longitudinal axis without cutting the elongate support member. 
     In another aspect of the invention, the venetian blinds include a headrail with an elongate cover having opposed ends, wherein the headrail has side wall stiffeners that provide increased structural integrity to the side walls when the opposed ends of the outer cover are subjected to cutting. 
    
    
     DRAWINGS 
     These features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying FIGS. where: 
     FIG. 1 is front view of venetian blinds having features of the invention; 
     FIG. 2A is a cross-sectional view of the venetian blinds of FIG. 1 taken along line  2 — 2 ; 
     FIG. 2B is crosssectional view of a first alternative set of venetian blinds having features of the invention; 
     FIG. 2C is a cross-sectional view of a second alternative set of venetian blinds having features of the invention; 
     FIG. 2D is a cross-sectional view of a third alternative set of venetian blinds having features of the invention; 
     FIG. 2E is a cross-sectional view of a fourth alternative set of venetian blinds having features of the invention; 
     FIG. 3 is a perspective view of venetian blinds having features of the invention; 
     FIG. 4 a cross-sectional view of the venetian blinds of FIG. 3, taken along line  4 — 4 ; 
     FIG. 5A is a cross-sectional view of the venetian blinds of FIG. 4, taken along line  5 — 5 ; 
     FIG. 5B is a crosssectional view of a fourth alternative set of venetian blinds having features of the invention; and 
     FIG. 6 is a perspective view of a fifth alternative set of venetian blinds having features of the invention. 
    
    
     DETAILED DESCRIPTION 
     The following discussion describes in detail two embodiments of the invention and several variations of those embodiments. This discussion should not be construed, however, as limiting the invention to those particular embodiments. Practitioners skilled in the art will recognize numerous other embodiments as well. 
     The invention is directed to venetian blinds  10  and methods of cutting the venetian blinds  10 . With reference to the embodiment illustrated in FIG. 1, the venetian blinds  10  generally comprise a slat-structure  12  depending downwardly from a headrail  14 . 
     The slat-structure  12  of the venetian blinds  10  comprises a plurality of horizontal spaced apart slats  16  that are supported by flexible cord members  18 . There are typically two flexible cord members  18  that function to support, lift, and tilt the slats  16 . The flexible cord members  18  typically cooperate with conventional lift and tilt mechanisms that attach to the headrail  14  of the venetian blinds  10 . 
     The headrail  14  is mounted to a support structure, such as a window frame. The headrail  14  has an open mounting surface  20  that is typically oriented towards the support structure. The headrail  14  contains mounting members  22  or cooperates with mounting members  22  that attach to the support structure. 
     Typically, the overall length of the headrail  14  is at least 3 feet. Preferably, the overall length of the headrail  14  is between about 4 feet and about 8 feet. Further preferable, the overall length of the headrail  14  is between about 4 feet and about 6 feet. 
     The headrail  14  comprises a elongate cover  24  made from a first material. The elongate cover  24  has a longitudinal axis and a pair of opposed ends  26 A. Typically, the opposed ends  26 A of the elongate cover  24  have end caps  28  attached at the termini of the elongate cover  24 . Referring to the alternative embodiments illustrated in FIG. 2, the elongate cover  24  typically has a generally planar bottom wall  30 A and two generally planar opposing side walls  32 A. The planar side walls  32 A have a free edge  34  and a bottom edge  36 . The bottom edge  36  of each generally planar side wall  32 A is adjoined to the bottom wall  30 A at an angle of about 90 degrees. The bottom wall  30 A and two side walls  32 A cooperate to define an elongate cover  24  configured as a substantially U-shaped trough that defines a generally open mounting surface  20 . 
     In an embodiment of the invention, the headrail  14  further comprises an elongate support member  38  attached coaxially to the elongate cover  24  to provide the elongate cover  24  with increased rigidity. The elongate support member  38  is made from a second material. The elongate support member  38  has a longitudinal axis and a pair of opposed ends  26 B. 
     In preferred embodiments, at least a portion of the elongate support member  38  has a shape that is complementary to the elongate cover  24 . Typically, the elongate support member  38  is sized and dimensioned to be complementary with the elongate cover  24  so that the elongate cover  24  wraps around the elongate support member  38 . As illustrated in FIGS. 2A and 2B, each generally planar side wall  32 A of the elongate cover  24  terminates in an inwardly curved rim  40  at its free edge  34 . The inwardly curved rim  40  straddles the elongate support member  38  and attaches the elongate support member  38  coaxially to the elongate cover  24 . Preferably, the elongate support member  38  slidably interconnects with the elongate cover  24  and reversibly attaches the elongate support member  38  coaxially to the elongate cover  24 . 
     In the embodiment illustrated in FIG. 2A, the elongate support member  38  has a generally planar bottom wall  30 B and two generally planar opposing side walls  32 B. In this embodiment, the elongate support member  38  is substantially U-shaped in cross-section and the two side walls  32 A of the elongate cover  24  wrap around the elongate support member  38  and the two inwardly curved rims  40  straddle the side walls  32 B of the elongate support member  38  and attaches the elongate support member  38  coaxially to the elongate cover  24 . 
     In the embodiment illustrated in FIG. 26, the elongate support member  38  has a generally planar bottom wall  30 B and one generally planar side wall  32 B such that the elongate support member  38  is substantially L-shaped in cross-section. The elongate support member  38  is sized and dimensioned to fit inside the elongate cover  24  and is shaped in accordance with the bottom wall  30 A and one side wall  32 A of the elongate cover. In this embodiment, one side wall  32 A of the elongate cover  24  wraps around the elongate support member  38  and one inwardly curved rim  40  straddles one side wall  32 B of the elongate support member  38  and attach the elongate support member  38  coaxially to the elongate cover  24 . 
     In the embodiment illustrated in FIG. 2C, the elongate support member  38  is substantially planar and is attached coaxially to the bottom wall  30 A of the elongate cover  24 . 
     In the embodiment illustrated in FIG. 2D, the elongate support member  38  comprises two substantially planar side walls  328  that are disposed adjacent to the side walls  32 A of the elongate cover  24 . 
     In the embodiment illustrated in FIG. 2E, the elongate support member  38  comprises a generally U-shaped member that, when inverted, fits within the U-shaped trough of the elongate cover  24 . 
     Referring to the embodiment illustrated in FIG. 1, the length of the elongate support member  38  along its longitudinal axis is less than the length of the elongate cover  24  along its longitudinal axis so that the opposed ends  26 A of the elongate cover  24  extend distally beyond the opposed ends  26 B of the elongate support member  38 . In this embodiment, the length of the first material of the elongate cover  24  can be reduced by cutting off a portion of at least one of its two opposed ends  26 A normal to its longitudinal axis without cutting the elongate support member  38 . Preferably, the elongate cover  24  is at least about 2 inches longer than the elongate support member  38 . Further preferable, the elongate cover  24  is at least about 4 inches longer than the elongate support member  38 . Still further preferable, the elongate cover  24  is between about 4 inches and about 10 inches longer than the elongate support member  38  and each opposed end  26 A of the elongate cover  24  extends beyond an opposed end  26 B of the elongate support member  38  by between about 2 inches and about 5 inches. 
     The second material of the elongate support member  38  is generally more rigid than the first material of the elongate cover  24 . Preferably, the first material is selected from the group consisting of plastics, fabrics, wood, metals, and composites. Preferably, the second material comprises a metal, such as aluminum or steel, because metals provide a high degree of rigidity and are relatively inexpensive. In a preferred embodiment, the first material is a plastic and the second material is sheet metal. Typically, the thickness of the first material is between about 0.1 mm and about 5 mm. More typically, the thickness of the first material is between about 0.5 mm and about 3 mm. Typically, the thickness of the second material is between about 0.1 mm and about 1 mm. The elongate cover  24  is typically colored, such as by dye or paint, so as to be aesthetically pleasing. 
     In another embodiment of the invention, the headrail  14  comprises side wall stiffeners  42  in abutment with the side walls  32 A of the elongate cover  24 . The side wall stiffeners  42  may be affixed to the side walls  32 A or detached from the side walls  32 A of the elongate cover  24 . Preferably, there is one side wall stiffener  42  disposed proximal to each opposed end  26 A of the elongate cover  24 . The side wall stiffeners  42  provide lateral support and increased structural integrity to the two generally planar side walls  32 A of the elongate cover  24  so as to inhibit lateral movement and vibration of the side walls  32 A of the elongate cover  24  in at least one direction. This support reduces the incidence of damage to the side walls  32 A when the opposed ends  26 A of the elongate cover  24  are subjected to cutting. In the embodiment illustrated in FIG. 4, the side wall stiffeners  42  are utilized in venetian blinds  10  in which the headrail  14  comprises an elongate support member  38 . In this embodiment, the side wall stiffeners  42  are preferably disposed at the opposed ends  26 A of the elongate cover  24  such that the side wall stiffeners  42  do not overlap with the elongate support member  38  along the longitudinal axis of the In the embodiment illustrated in FIG. 6, the side wall stiffeners  42  are utilized in venetian blinds  10  in which the headrail  14  does not comprise an elongate support member  38 . 
     In the embodiment illustrated in FIGS. 5A and 6, the side wall stiffeners  42  are hollow and substantially rectangular in cross-section so as to define a shape of that of a rectangular parallelepiped. The side wall stiffeners  42  are disposed within the U-shaped trough defined by the elongate cover  24  and one side wall stiffener  42  is located proximal to each opposed end  26 A of the elongate cover  24 . In these embodiments, the length of each side wall stiffener  42  along the axis parallel to the longitudinal axis of the elongate cover  24  is typically between about 2 inches and about 5 inches. However, the side wall stiffeners  42  may be shorter or longer in other embodiments. 
     The shape and configuration of the side wall stiffeners  42  is not limited to any particular design. The side wall stiffeners  42  can be sized, shaped, and configured differently as long as they inhibit lateral movement and vibration of the side walls  32 A in at least one direction. For example in alternative embodiments (not shown), the side wall stiffeners  42  are substantially solid and made from a material such as, for example, a stiff foam, plastic, or wood. In the embodiment illustrated in FIG. 5B, each side wall stiffener  42  is substantially X-shaped in cross-section and elongate. In an alternative embodiment (not shown), each side wall stiffener  42  comprises a generally planar top wall attached to at least a portion of the free edge  34  of each opposed side wall  32 A of the elongate cover  24 . In this embodiment, at least a portion of the opposed ends  26 A of the elongate cover  24  are generally rectangular in cross-section. In other embodiments, the side wall stiffeners  42  are not elongate with respect to the longitudinal axis of the elongate cover  24 . For example, each side wall stiffener  42  may comprise a rod, bar, arm or similar such article that transverses the U-shaped trough and is in abutment with each opposing side wall  32 A. Alternatively, each side wall stiffener  42  may comprise a generally U-shaped member that, when inverted, fits within the U-shaped trough so as to provide two linear segments in abutment with the side walls  32 A and one substantially linear segment that transverses between the side walls  32 A. 
     In order to cut the Venetian blinds  10  described herein, the venetian blinds  10  described above are selected and retained in a relatively immobile cutting position. If an embodiment with an elongate support member  38  is selected, the headrail  14  is cut such that the length of the first material of the elongate cover  24  is reduced without cutting the elongate support member  38 . The slat-structure  12  is cut to about the same length as the headrail  14  so that the overall width of the Venetian blinds  10 , as defined by the length of the headrail  14  and the length of the slat-structure  12 , is substantially equivalent. The slat-structure  12  may be cut substantially simultaneously with the headrail  14  or independently of the headrail  14 . 
     When an embodiment having side wall stiffeners  42  is selected, a person cuts at least a portion of the headrail  14  proximal to the side wall stiffeners  42  such that the headrail  14  is substantially free from breaking or chipping upon being cut and also cuts the slat-structure  12  so that the slats  16  are about the same length as the headrail  14 . This method may be used in embodiments having an elongate support member  38  or in embodiments not having an elongate support member  38 . 
     Having thus described the invention, it should be apparent that numerous structural modifications and adaptations may be resorted to without departing from the scope and fair meaning of the instant invention as set forth hereinabove and as described hereinbelow by the claims.

Summary:
The invention is a venetian blind which incorporates an elongate support member as part of the header which allows the width of the blinds to be reduced by cutting without having to cut through the support. The invention also includes venetian blinds that have a header which is better suited to being cut without incurring damage.