Abstract:
A sign system with a frame and at least one sign. The sign has at least one protruding ridge extending from the backside with the ridge having a narrow neck portion proximate the backside. At least one clamping unit is fixed to the frame with at least one pair of clamps to securely the neck portion of the ridge such that the frame is reversibly but securely fastened to the frame.

Description:
FIELD OF INVENTION  
       [0001]     This invention relates to a sign system, and in particular an easily removable sign system for ease of replacement and handling.  
       BACKGROUND OF INVENTION  
       [0002]     Signs, in particularly signs that are used in buildings with multiple tenants, are known to have a frame with replaceable sign strips for ease of replacement. For example,  FIG. 1  shows a prior art wall-mounted sign system that has a pair of wall mounted columns  20  adapted to allow the directory panel or sign strips  22  to be clamped thereon via brackets  24  attached to the back of the strips. The sign strips in this example have to be removed from the top one by one, such that if a strip from the bottom of the stack of strips needs to be changed, all the strips have to be removed by sliding upwards from columns  20 .  
         [0003]     In another prior art example as shown in  FIGS. 2A and 2B , The sign strips  26  are mounted onto the wall-mounted column  28  via clips  30  that have a cross-section shape generally of a semi-circle. The sign strips  26  have flanges  32  adapted to grip onto the clips. These strips may be plugged out from the columns individually from the front, but due to wide flanges  32  used for mounting to the clips  30 , a big gap has to be provided between sign strips to provide sufficient space for access and removal from the front  26   a    
         [0004]     In some prior art methods the sign strips are difficult to mount and demount, while in other prior art methods, the signs are too readily pried off.  
       SUMMARY OF INVENTION  
       [0005]     In the light of the foregoing background, it is an object of the present invention to provide an alternate sign assembly.  
         [0006]     Accordingly, the present invention, in one aspect, provides a sign system comprising a frame and at least one sign with a front side and a back side. The sign has at least one protruding ridge extending from the backside with the ridge having a narrow neck portion proximate the backside. At least one clamping unit is also provided with at least one pair of clamps, with the clamping unit fixed onto the frame, and the clamps adapted to receive and clasp the ridge such that the clasping edge of the each clamp extends securely into the neck portion of the ridge wherein the edges of the pair of clamps grip the neck portion in opposing sides when the sign is fixed onto the frame such that the frame is reversibly but securely fastened to the frame.  
         [0007]     In the preferred embodiment, the clamping unit comprises a base adapted for attachment to the frame, with the clamps extending from the base. The clamping unit further comprises struts extending from the base on either side of the clamps, the struts adapted to abut against the sign when the ridge is fastened to the clamps such that the sign is in the desired alignment position. In the most preferred embodiment, the struts from either side of the clamps are of the same length such that the plane of the sign is precisely aligned with the plane of the frame when attached thereto.  
         [0008]     In another preferred embodiment, the pair of clamps protrudes from the base at an inclined angle and tilting towards each other to create a narrow entrance with an expanding space therebetween, such that the ridges may be inserted into the expanding space with the neck extending through the narrow entrance when the sign is inserted into the clamping unit.  
         [0009]     In yet another preferred embodiment, the traverse cross section of the ridge is in the general shape of a diamond with one end of the diamond attached to the sign to form the neck. In the most preferred embodiment, the distal end of the diamond points away from the sign and the proximal end are attached to the sign to form the neck. The diamond shaped-ridge further comprises an enlarged mid-section whereby the distal end and the mid-sections are inserted into the expanding space when the sign is attached to the clamping unit.  
         [0010]     There are many advantages to the present invention. The neck portion of the fastening member at the back of the sign allows slight angular motions of the sign such that it can be pried from the frame for ease of replacement. In the most preferred embodiment, the ridge or ridges run along the interior area of the sign, acting as the center of rotation for the sign to rotate during the removal process. Yet the neck portion also allows the clamps to tightly secure the sign to the wall frame. In another embodiment, one or more ridges are provided along the interior surface of the back of the strip, keeping the edges of the strip approximately the same thickness as the interior.  
         [0011]     In the preferred embodiment, the two clamps are arranged to grip the sign from the two sides of the ridge that is parallel to the longitudinal edge of the sign such that the rotational movement of the sign as it is detached from the frame results in a force having the same direction as the clamping force of the clamps, thereby reducing the clamping force and making the removal process easier without causing damage to the clamps.  
         [0012]     Another advantage of the present invention is that the ridges are preferably provided within the interior areas of the sign such that there are no flanges along the edge of the sign as found in the prior art assembly shown in  FIGS. 2A and 2B . As a result, the gap between the strips may be substantially narrowed because more space is needed for the rotation of the prior art strip with a wide flange to clear away from an adjacent strip by rotational movement. The possibility of aligning the strips one next to another in a compact manner according to the present invention with virtually invisible gaps therebetween improves the aesthetic appearance of the sign assembly.  
     
    
     BRIEF DESCRIPTION OF FIGURES  
       [0013]      FIG. 1  shows one prior art sign system.  
         [0014]      FIGS. 2A and 2B  show the front perspective view and cross sectional view of another prior art sign system. In  FIG. 2B , 3 different signs of varying heights are shown  
         [0015]      FIG. 3  shows a frame according to one embodiment of the present invention with two clamping units provided thereon. An enlarged view of one corner of the frame is also shown.  
         [0016]      FIGS. 4A, 4B  and  4 C shows the front, back and traverse cross-sectional view of a sign in the form of a strip according to one embodiment of the present invention.  
         [0017]      FIGS. 4D and 4E  show the isometric view and cross-sectional view of two other sign strips, respectively, according to other embodiments of the present invention.  
         [0018]      FIG. 5A  shows the top perspective view of a plurality of clamping units according to one embodiment of the present invention.  
         [0019]      FIG. 5B  shows the longitudinal cross-sectional view across line A-A of the clamping units of  FIG. 5A .  
         [0020]      FIG. 6A  is an isometric view of a sign system according to the present invention with the sign attached to the frame.  
         [0021]      FIG. 6B  is a cross sectional view across lines B-B of  FIG. 6A .  
         [0022]      FIG. 6C  illustrates the interaction between the clamping units and the ridge of the sign strip when the ridges are mounted onto the clamping units. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     Referring first to  FIG. 3 , a frame according to the present invention is provided with top and bottom metal strips  35   a , left and right side metal strips  35   b  and mounting holes  36 . The left and right side metal strips  35   b  contain a supporting border  38  and two tracks  40  running parallel to the longitudinal axis (shown as dotted line  42 ) of the metal strip. In this embodiment, the two tracks  40  define a longitudinal space  41  therebetween with the inner edges of the tracks  40   a  provided with a beveled shape. In  FIG. 3 , four clamping units  45  are shown attached to the frame with two on either side of the frame. In this embodiment, the clamping units are fixed onto the frame by sliding the base of each unit (see  FIGS. 5A and 5B ) into the space  41  between the tracks  40 .  
         [0024]     Turning now to  FIG. 4A  to  4 C, a sign strip  43  according to the present invention is provided with a front illustration surface  44  on which the content of the sign, such as the name of the company, can be fixed. In this embodiment, the two longitudinal edges  44   a  of the front side of the sign are raised such that a display sheet may be embedded into the front surface of the sign without the edges of the display sheet showing or being exposed. The back of the sign is formed into a ridge that spans across the entire length of the sign along the center and longitudinally.  
         [0025]     In the embodiment shown in  FIG. 4C , the ridge  46  is of a general shape of a diamond, with the proximal end of the diamond shape pointing towards the sign strip and formed into a neck  46   a . The distal end of the ridge  46   b  is provided for interaction with the clamping unit as shall be shown below. The ridge is preferably formed as an integral part of the sign strip using, for example, extrusion of aluminum strips.  
         [0026]     Referring to  FIGS. 5A and 5B , a series of clamping units may be fixed onto the frame contiguously (only the units are shown in  FIGS. 5A  and B for ease of description). The clamping units of the preferred embodiment each contain a pair of clamps  48  within a pair of struts  50 . The clamps protrude from the base  53  at an inclined angle and tilting towards each other to create a narrow entrance  52  with an expanding space  54  therebetween. Also in the preferred embodiment, the distal ends of the clamps are formed into a barrel shape  56 . The struts in this embodiment point perpendicularly from the base.  
         [0027]     During the attachment process, the ridge  57  of the sign strip  58  is fitted into the space  54  of the clamping unit through entrance  52  as shown in  FIGS. 5A, 5B  and  6 C. In this embodiment, the sign strip contains two ridges running in parallel along the entire length of the strip and at a distance from the edge of the strip. Due to the barrel shape of the distal end of the clamp, the neck of the ridge is firmly gripped by the clamp, while the enlarged space  54  created by the inclined angle accommodates the diamond-shaped head with ease without creating outward pressure to the clamping pair once the corresponding section of the ridge is inserted. The inclined angle of the clamps also creates a resilience force on opposing sides of the neck to ensure exceptional security once the sign is fixed. Also shown in  FIG. 6A  are two other sign strips  60  and  62  juxtapose strip  58 . In this preferred embodiment, a narrow gap  64  of 0.5 mm is provided between each sign strip.  
         [0028]     When a user wishes to disengage the sign strip from the frame, for example for changing or cleaning, a thin rigid sheet may be inserted into gap  64  in between two strips to pry away the strip. In the preferred embodiment, the prying force is applied toward the frame and in a rotational manner (shown by arrow  66  in  FIG. 6C ) resulting in strip  58  being pried out of the clamps in a rotational movement as shown in arrow  68 . Since the gripping force of the clamps (on opposing directions along line A-A) is along the same direction as the prying force shown by arrow  66 , the prying force directly reduces the clamping force of the clamps, thereby reducing the force required to pull the sign from the frame.  
         [0029]     Also in the preferred embodiment, the thin rigid sheet has a working thickness equal to the width of the gap for example, 0.5 mm following the example of the preferred gap described above. Most preferably, at least one edge of the rigid sheet is beveled with the thinner side having a thickness of, for example, 0.3 mm, such that it can be easily inserted into the gap  64  between two strips.  
         [0030]     The preferred embodiments of the present invention are thus fully described. Although the description and drawings referred to particular embodiments, it will be clear to one skilled in the art that the present invention may be practiced with variation of these specific details. Hence this invention should not be construed as limited to the embodiments set forth herein.  
         [0031]     For example, the frame is described to have metal strips but any other materials may be used according to the preference of the user, such as wood or plastic. The signs shown and described are strips but the signs may clearly be of many other shapes. Furthermore, the strips may be fixed to the frame vertically.  
         [0032]     The sign strips are described to contain raised edges  44   a  that act as margins to assist a user in aligning the display sheets (such as company name) flush against the edge of the strip during the in-laying process before it is fixed or glued thereon. The raised edges may also protect the edges of the display sheet pasted onto the front surface  44  of the strip from being inadvertently lifted. However, the raised edges are only a preferred embodiment, and the same invention may be practiced without these raised edges. Furthermore, other shapes of the sign strip may also be used, two examples of which are illustrated in  FIGS. 4D and 4E . For ease of illustration, the same corresponding parts are given the same reference numerals.  
         [0033]     The display sheets are described as being metallic. Some examples of metallic sheets are aluminum plates, Aluma Jet or Metalphoto plates. However, it is clear that they can be made from any material, including but not limited to non-metallic material such as silk screen panels, plastic sheets, etching panel etc. These sheets or panels are not necessarily flat, and may even be raised or embossed, according to the user&#39;s requirements.  
         [0034]     The gap in between strips is described as preferably 0.5 mm. This dimension is for illustration only and should not be construed to limit the scope of the claims. A narrow gap of 0.5 mm or less provides a desirable appearance for some, but if another user prefers a much larger gap, the present invention can also be practiced accordingly.  
         [0035]     The ridge is described as having a “diamond shape” in the preferred embodiment simply for ease of description. It would be understood that any other shape with a restriction at the attachment site to the sign may act as the neck to receive the distal edge of the clamp. The distal edges of the clamps are described as being barrel or cylindrical in shape. Again, it is clear that this is only one embodiment of the present invention, and that any other shapes providing an enlarged edge would fall within the scope of the present invention.  
         [0036]     Clamping units are described to have struts but the clamps can function without them. The struts are provided to ensure that the signs do not tilt or rotate according to the direction shown in arrow  68  or  66 . Using the struts, all the sign strips lying across the front of the frame will run on the same plane, giving a very neat appearance. Each clamping unit is described as containing one pair of clamps and one pair of struts, but it is clear that a plurality of pairs of clamps and struts may be formed into one strip as a clamping unit, depending on the size of the frame and sign, and the requirements of the users.