Abstract:
This disclosure is concerned with a readily changeable sign display system which facilitates easy alteration of the sign indicia displayed but is also resistant to unauthorized tampering so that it can be deployed where it is not under continuous surveillance when exposed to the general public. It comprises vertical frame members which provide tracks for the insertion of horizontal frame members. In some embodiments the vertical frame members are joined to each other with a backing member while in other embodiments intermediate channel members are placed between the vertical frame members and adjacent members are joined by a backing member. The horizontal frame members carry grooves for the insertion of sign panels which carry indicia. The tracks for the horizontal frame members carry removable obstructions which hold these members in the tracks. The obstructions at the upper end of the tracks are readily removable.

Description:
BACKGROUND OF THE INVENTION 
     There are numerous designs for sign systems in which the messages imparted by the overall sign can be changed. The location of the sign system may have an impact on the ease with which these messages may be changed. One convenient approach is a sign system with changeable panels. On the one hand, there is a desire to facilitate changes and minimize the time and effort involved. But if the sign system is located where it is not under continual surveillance by authorized person while it is exposed to the general public, there is a concern with inhibiting unauthorized changes. These opposing goals are readily evident in the case of directional signs in buildings with multiple facilities, such as an office building with multiple tenants. The signs are often located where they are only observed by the general public during the time that the building is open but frequently require alteration as tenants change. It is advantageous if the changes can be made without the need to have a key or other unique opening device. 
     SUMMARY OF THE INVENTION 
     The present invention involves a sign system which accommodates interchangeable panels which can be readily loaded into and removed from a frame structure but which are secured in a manner which inhibits tampering once the panels are in place. The panels are preferably flat rectangular pieces with information displayed on one or both of their faces. The sign system preferably comprises vertical frame members which are designed to be affixed to some structure, such as a wall, that is located at the site where the information on the panels is to be displayed. These frame members should each carry a vertical groove which extends from the top edge of its frame member along the frame member&#39;s long dimension. The frame members used in a given sign system should preferably have grooves of the same width and in a preferred embodiment the grooves should also have the same depth. In a particularly preferred embodiment the frame members of a given sign system are essentially identical to each other. In a preferred embodiment these frame members are mounted on one or more flat backing members which hold these frame members parallel to each other at a fixed distance from each other with their grooves facing each other. In a preferred embodiment the backing members extend into the grooves of the backing members. In one preferred embodiment two framing members are affixed to a common backing member with their grooves facing each other. In another preferred embodiment one or more intermediate channel members is interposed between the vertical framing members. This intermediate channel member has two grooves running along its long dimension and facing out in two opposite directions. Theses grooves should have about the same width and more preferably the same depth as the grooves carried by the vertical frame members. It is preferred that a separate backing member be used to connect each vertical frame member to its adjacent intermediate channel member and it is particularly preferred that the backing member joining a given vertical frame member to its adjacent intermediate channel member extend into the grooves of both. In sign systems with more than one intermediate channel member it is preferred that adjacent intermediate channel members be joined by separate backing members such that a separate backing member runs between each pair of adjacent vertical members whether they are vertical frame members, intermediate channel members or a combination of the two. It is particularly preferred that every backing member extend into the appropriate grooves of the two vertical members which it joins. 
     The vertical frame members and the intermediate channel members, when present, provide via their grooves tracks for horizontal frame members. These horizontal frame members comprise an essentially flat back portion which has two opposed sides which each carry a flange which is generally perpendicular to the flat back portion. Each flange in turn carries a groove which faces inward toward the groove carried by the other flange. The two grooves have about the same width and preferably the same depth. These two grooves provide a track for the insertion of a sign panel. In this regard, one of the other sides of the horizontal frame member is unobstructed such that a sign panel can be readily slid into and out of the tracks provided by the grooves carried by the flanges. In a preferred embodiment the horizontal frame member has a generally rectangular shape and in a particularly preferred embodiment both of the edges of this rectangular shape which do not carry flanges with the opposed grooves are unobstructed such that sign panels can be readily slid in and out of the tracks provided by the grooves carried by the flanges. In another embodiment the horizontal frame member is provided in two similar pieces, each of which is of the same width and has a flange with a groove which faces inward towards its flat back portion. When mounted in the track provided by the vertical frame members and/or the intermediate channel members, the two grooves provide a track for holding a sign panel. In this case the sign panel is typically loaded into the upward facing groove and then the downward facing groove is placed over the sign panel. This arrangement accommodates sign panels of various heights greater than can be conveniently accommodated with a single piece horizontal frame member. 
     Each of the tracks for the horizontal frame members provided by the grooves of two vertical frame members, two intermediate channel members or a combination of one of each is provided with one or more semi-permanent obstructions at its bottom terminus such that vertical frame members can be loaded into a track from the top and be retained within the track. Preferably the obstructions are affixed to the two vertical frame members, the intermediate channel members or both. In a particularly preferred embodiment the obstructions are caps which extend from the center of a frame or channel member across the groove or grooves carried by this member. In a particularly preferred embodiment these frame and channel members carry a recess which accommodates a fastener which passes through the cap. In an alternative embodiment the obstruction is provided by a member which is affixed to the backing member which joins the frame and/or channel members which define a given track. In this embodiment the obstruction may conveniently be a right angle piece with one arm being parallel to and affixed to the backing member, for example with an adhesive, and the other arm extending perpendicularly from the backing member across the track. 
     Each of these tracks is also provided with one or more readily removable obstructions at its upper end. In a preferred embodiment the obstructions are affixed to the two vertical frame members, the intermediate channel members or both. The obstructions should be affixed in a manner such that they can readily be removed with less effort than the removal of screw which requires multiple rotations for removal. In a preferred embodiment the obstructions are affixed using two piece removable rivets in which a central portion can be easily withdrawn by the application of a small amount of force beneath its head and this in turn allows the main body of the rivet to be withdrawn. In an alternative embodiment the obstructions may be affixed using magnetic attraction, for instance by having the obstruction be at least partially constructed of a magnetically responsive metal like steel and having the backing member carry a small flat appropriately placed magnet. In a particularly preferred embodiment the obstructions are caps which extend from the center of a frame or channel member across the groove or grooves carried by this member in a manner similar to that of the caps which may be used as obstructions at the bottom terminus of the tracks. In a particularly preferred embodiment these frame and channel members carry a recess which accommodates a readily removable fastener such as a two piece removable rivet which passes through the cap. In an alternative embodiment the obstruction is provided by a member which is affixed to the backing member which joins the frame and/or channel members which define a given track. In this embodiment the obstruction may conveniently be a right angle piece with one arm being parallel to and affixed to the backing member, for example by magnetic attraction, and the other arm extending perpendicularly from the backing member across the track. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a sign display system showing the all the elements of the system as well as the sign panels which it is used to display. 
         FIG. 2  is a top view of a vertical frame member used to provide mounting tracks 
         FIG. 3  is a perspective view of an intermediate channel member which, when used, cooperates with vertical frame members and/or other intermediate channel members to define tracks for the horizontal frame members. 
         FIG. 4  is a side elevation of a horizontal frame member which is used to carry sign panels carrying indicia. 
         FIG. 5  is a side elevation of a partial horizontal frame member which is one of a pair used to hold larger sign panels carrying indicia. 
         FIG. 6  is a perspective view of an obstruction which cooperates with a vertical frame member to close a track for a horizontal frame member. 
         FIG. 7  is a perspective view of an obstruction which cooperates with an intermediate channel member to close tracks for the horizontal frame members. 
         FIG. 8  is a perspective view of a two piece removable rivet with its center pin removed which is used to affix an obstruction to a vertical frame member or an intermediate channel member. 
         FIG. 9  is a perspective view of a two piece removable rivet with its center pin in a locking position. 
     
    
    
     DETAILED DESCRIPTION 
     One embodiment of the sign display system  100  with which the present invention is concerned is illustrated in  FIG. 1 . A vertical frame member  110  is joined to the left side of an intermediate channel member  120  by a flat backing member  200 . The flat backing member  200  has been inserted into the groove  112  (Illustrated in  FIG. 2 ) of the vertical frame member  110  and one of the grooves  122  (Illustrated in  FIG. 3 ) of the intermediate channel member  120 . It may be conveniently adhesively adhered to the appropriate portion of the back plate  114  (Illustrated in  FIG. 2 ) of the vertical frame member  110  and to the appropriate portion of the back plate  124  (Illustrated in  FIG. 3 ) of the intermediate channel member  120 . Thus the flat backing member  200  serves to hold the vertical frame member  110  and the intermediate channel member  120  parallel to each other and to align their grooves  112  and  124  such that they face each other. The facing grooves  112  and  122  define a track for the horizontal frame members  130 . Each horizontal frame member  130  may carry a sign panel  210  which bears informational indicia  210 . The horizontal frame members  130  are retained in the sign display system  100  by the side caps  150  and the center caps  160 . Both caps  150  and caps  160  have a portion which extends over one of the grooves  112  and  122 . The side cap  150  and the center cap  160  which are affixed to the top of the sign display system  100  are secured by removable two piece rivets  170  which consist of a center pin  172  and a four lobe body  174 . The vertical frame member  110  has a fastener receptacle  118  to receive the four lobe body  174  and the intermediate channel member  120  has a fastener receptacle  128  to receive the four lobe body  174 . The side cap  150  and the center cap  160  which are affixed to the bottom of the sign display system  100  are secured by a semi-permanent combination of a screw  180  and an anchor  190 . Both the vertical frame member  110  and the intermediate channel member  120  have respective recesses  118  and  128  to receive the anchors  190 . In this regard, both the vertical frame member  110  and the intermediate channel member  120  are symmetrical about the horizontal plane such that each can be rotated 180° and still mate with each other and accept the removable two piece rivets  170  at the top and the screws  180  and anchors  190  at the bottom. 
     A second vertical frame member  110  is joined to the right side of the intermediate channel member  120  by a flat backing member  200  in the same manner and it carries side caps  150  at its top and bottom in the same manner as the first vertical frame member  110  using the anchor  190  and screw  180  at the bottom and the two piece removable rivet  170  at the top. 
     The detailed construction of the major members is illustrated in  FIG. 2-4 . The vertical frame member  110  has a groove  112  to accommodate the flat backing member  200  as well as the horizontal frame member  130 . The groove  112  is formed between the back plate  114  and the front plate  116 . The back plate  114  provides an interior surface  115  to which the flat backing member  200  may be adhesively adhered. The vertical frame member  110  also has a fastener receptacle  118  which can accommodate either the four lobe body  174  of the two piece removable rivet  170  or the anchor  190  and the screw  180 . The vertical frame member  110  has mirror image symmetry across a plane extending in z direction so that it can serve as either the left hand or the right hand terminus of the sign display system  100 . The intermediate channel member  120  has two grooves  122  which each accommodate a flat backing member  200  as well as a horizontal frame member  130 . The grooves  122  are formed between the back plate  114  and the front plate  116 . The back plate  124  provides an interior surface  125  to which the flat backing members  200  may be adhesively adhered. The horizontal frame member  130  has two grooves  134  which accommodate a sign panel  210 . These grooves  134  are formed in its flanges  132 . The horizontal frame member  130  has a back portion  136  which in combination with the flange front face  133  provides the appropriate thickness to fit fairly snugly in the grooves  112  and  122  of the vertical frame member  110  and the intermediate channel member  120 , respectively, when a portion of each groove is already occupied by a flat backing member  200 . The back portion  136  has a series of indentations  138  which serve to reduce the total amount of material needed to fabricate the horizontal frame member  130 . 
     An alternative partial horizontal frame member is illustrated in  FIG. 5 . It has a single groove  144  formed in its single flange  142 . It has a back portion  146  which in combination with the flange front face  143  provides the appropriate thickness to fit fairly snugly in the grooves  112  and  122  of the vertical frame member  110  and the intermediate channel member  120 , respectively, when a portion of each groove is already occupied by a flat backing member  200 . The back portion  146  has an indentation  148  which serves to reduce the total amount of material needed to fabricate the partial horizontal frame member  140 . In cases in which it is inconvenient to fabricate a single horizontal frame member  130  to accommodate a particularly tall sign panel  210 , a partial horizontal frame member  140  may be positioned over the top and the bottom of the sign panel  210 . One procedure would be to load one partial horizontal frame member  140  into the track defined by a vertical frame member  110  and the intermediate channel member  120 , place the particularly tall sign panel  210  into the groove  140  of this partial horizontal frame member  140  and then place another partial horizontal frame member  140  into this track so that its groove  144  fit over the top of this sign panel  210 . 
     The side caps  150  which are affixed to the top and the bottom of the vertical frame members  110  are illustrated in  FIG. 6 . They have wings  152  which extend over the grooves  112  of the vertical frame members  110 . They also have a well  154  which accommodates either the head  171  of the two piece removable rivet  170  or the head of the screw  180 . They also have an aperture  156  through which the rivet  170  or the screw  180  passes when seating in the fastener receptacle  118  of a vertical frame member  110 . They also have an access channel  158  which allows access to the head  176  (Illustrated in  FIG. 8 ) of the rivet center pin  172  to facilitate removal of the center pin and consequently the four lobe body  174 . This channel  158  is, of course, unnecessary when the side caps  150  is affixed to the bottom of a vertical frame member  110  but it is convenient to mold a common side cap  150  for both the top and the bottom. 
     The center caps  160  which are affixed to the top and the bottom of the intermediate channel member  120  are illustrated in  FIG. 7 . They have wings  162  which extend over the grooves  122  of the intermediate channel member  120 . They also have a well  164  which accommodates either the head  171  of the two piece removable rivet  170  or the head of the screw  180 . They also have an aperture  166  through which the rivet  170  or the screw  180  passes when seating in the fattener receptacle  128  of the intermediate channel member  120 . They also have access channels  168  which allow access to the head  176  (Illustrated in  FIG. 8 ) of the rivet center pin  172  to facilitate removal of the center pin and consequently the four lobe body  174 . These channels  168  are, of course, unnecessary when the obstruction  150  is affixed to the bottom of the intermediate channel member but it is convenient to mold a common center cap  160  for both the top and the bottom. 
     The details of the construction of the two piece removable rivet  170  are illustrated in  FIGS. 8 and 9 . A center pin  172  with a head  176  is used to lock the rivet in place. It passes through the aperture  173  of the four lobe body  174 . The head  171  of the two piece removable rivet  170  seats in the well  154  or  164  of the side or center caps  150  or  160 , respectively. When the center pin  172  is inserted it caused the four lobe body  174  to expand. In this manner a rivet  170  may be locked in place in the fastener receptacle  118  or  128  of the vertical frame member  110  or the intermediate channel member  120 , respectively. The head  171  is provided with access channels  178  which allow access to the head  176  thus facilitating removal of the center pin  172  and consequently the four lobe body  174 . These channels  178  cooperate with the access channel  158  of the side cap  150  or with the access channels  168  of the center cap  160 . 
     A typical sign display system is between about 1.425 inches and 9.05 inches tall and about 7.1 inches wide without an intermediate channel member and about 14.5 inches wide with one intermediate channel member. The typical horizontal frame member accommodates a sign panel that is about 6.1 inches in width and between 2 and 8 inches in height. 
     The vertical frame member, the intermediate channel member and the horizontal frame member are preferably made of metal and more preferably, for ease and economy of manufacturing, of extruded metal. It is especially preferred to fabricate them as extruded aluminum parts. This not only provides for ease and economy of manufacturing but also provides a sign display system which is light weight and corrosion resistant. 
     The flat backing member and the end and center caps are conveniently made of plastic. The flat backing member is preferably made of a plastic material available in readily cut sheets such as ABS. The end and center caps are preferably fabricated by injection molding. 
     While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.