Abstract:
A portable sign assembly having a base assembly which includes a leg member pivotally interconnected with a base plate of the base assembly. A leg release mechanism is further provided for selectively locking a respective leg from pivoting relative to a respective base plate. The release mechanism includes a lock-pin that is slidably disposed through the leg and is biased in a first position by a biasing member disposed within the leg. The lock-pin selectively engages apertures of the base plate for prohibiting pivotal motion between the leg and the base plate.

Description:
FIELD OF THE INVENTION 
     The present invention relates to portable sign stands, and more particularly, to a leg release mechanism for quickly and easily locking a sign stand leg in a retracted or protracted position. 
     BACKGROUND OF THE INVENTION 
     There are many uses for signage products today, particularly for traffic control at road construction sites and other work areas along the nation&#39;s highways. Many of these signage products utilize portable sign stands or sign holders for temporarily locating and displaying signs of various sizes and shapes. Rigid signs such as aluminum or plywood have typically been used in such applications. However, there has been a recent trend, particularly with portable traffic control signage, towards the use of flexible, roll-up signs, which have been well-received due to their lightweight and compact nature. It is anticipated that this trend will continue due to benefits gained by the compactness, portability and storability of flexible sign systems, as well as the durability of their design and the minimal maintenance required for their upkeep. 
     In general, various portable sign stands have been developed which utilize an upright that is attached to a base assembly having a leg assembly including a number of legs that pivotally and telescopically extend to support the sign. In addition, the legs are generally positionable between a retracted position wherein the legs are positioned closely parallel to the upright for convenient storage and a protracted position wherein the legs extend outwardly from the upright for securely supporting the sign. A release mechanism is incorporated into the base assembly for releasably securing the legs in the retracted or protracted position. The base assembly often includes a resilient spring member between the leg assembly and the upright to control deflection of the sign whenever a force is applied thereto, such as a gust of wind impinging upon the sign panel. 
     The flexible roll-up sign has a pair of brace members attached to the corners of a flexible sign panel which in a deployed or use position form a cross configuration. Various fasteners can be used for this purpose including twist lock fasteners, hook and loop type fasteners, snaps, plastic pockets or stretchable rubber or elastic straps. Fasteners of the latter type are marketed and sold by Marketing Displays International, Inc. of Farmington Hills, Mich. under the trademark DuraLatch™. The flexible roll-up sign is releasably secured to the sign stand by a locking mechanism such as a cam lock or lock pin assembly. 
     Preferred embodiments of the type of sign stands described above are disclosed in the following U.S. patents: U.S. Pat. No. 6,056,250 entitled “Improved Sign Stand For Flexible Traffic Control Signage”, U.S. Pat. No. 6,032,908 entitled “Sign Stand With Cam Release Assembly” and U.S. Pat. No. 5,472,162 entitled “Cap Lock For Sign Stand.” The above-referenced applications are commonly owned by the assignee of the present invention and the disclosures are expressly incorporated by reference herein. 
     Signage systems of the type described above have several moving parts that must operate easily and repeatedly in adverse conditions with little or no maintenance. These signage systems are commonly set up along busy roads and highways such that continuous efforts are made to improve the ease of use and durability of these systems. In this regard, there is a need to provide a release mechanism for the leg assembly, and more particularly to provide a simpler, more cost-effective release mechanism for the leg assembly which is simple to assemble, quick and easy to operate and requires no significant maintenance and is substantially wear-resistant. 
     SUMMARY OF THE INVENTION 
     It is a principle object of the present invention to provide a portable sign stand having an improved leg release mechanism for releasably positioning the legs of the stand between a retracted position and multiple protracted positions. 
     It is another object of the present invention to provide a method of constructing an improved leg release mechanism, which is low in cost and simple to manufacture and assemble. 
     It is a further object of the present invention to provide an improved “foot-operated” leg release mechanism for releasably locking the leg assembly in the retracted or protracted positions. 
     Accordingly, the present invention is directed to a portable sign stand comprising a base assembly having a leg pivotally connected to a base plate and a release mechanism for selectively permitting pivoting of the leg relative to the base plate. The release mechanism includes a lock-pin slidably disposed through a cavity of the leg between a first and second position. In the first position the lock-pin extends into an aperture of the base plate and in the second position the lock-pin is withdrawn from the aperture. A biasing member is disposed within the cavity and in direct connection with the lock-pin for biasing the lock-pin in the first position. When the lock-pin is in the first position pivoting of the leg relative to the base plate is disabled. When the lock-pin is in the second position pivoting of the leg relative to the base plate is enabled. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is an environmental perspective view of the portable sign stand of the present invention; 
     FIG. 2 is a perspective view of the leg release mechanism of the present invention; 
     FIG. 3 is a cross-section of the top plan view of the leg release mechanism in a locked mode; 
     FIG. 4 is a cross-section of the side elevation view of the leg release mechanism; 
     FIG. 5 is a cross-section of the top plan view of an alternate embodiment of a leg release mechanism in a locked mode; and 
     FIG. 6 is a cross-section similar to FIG. 5 with the leg release mechanism in a released mode. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     With reference to the figures and in accordance with the teachings of the present invention, a portable sign assembly  10  is provided having a base assembly  12  and a sign assembly  14 . The base assembly  12  includes a pair of base plates  16  secured to a pair of spring members  18 . An upright  20  extends upward from the spring members  18  for selectively receiving a portion of a vertical brace  22  of the sign assembly  14 . The upright  20  includes a sign release mechanism  24  for selectively fixing the vertical brace  22  within the upright  20 . The sign assembly  14  includes the vertical brace  22  and a horizontal brace  26  for forming a cross configuration for supporting a flexible sign panel  28 . As presently preferred, the spring members  18  are operably disposed between the base assembly  12  and the upright  20  such that the sign assembly  10  is resiliently supported from the base assembly  12  so as to flex when a wind load is applied, thus preventing the portable sign assembly  10  from tipping over. It should be appreciated that while the spring members  18  are depicted as a pair of coil springs, it may comprise a single coil spring or any other component or components that have the required resilience characteristics. 
     The base assembly  12  further includes four leg assemblies  30 , each leg assembly  30  pivotally connected to the base plates  16  by a threaded fastener  32 . Leg assembly  30  is of the telescopic type having an outer leg section  34  pivotally coupled to the corresponding base plate  16  and an inner leg section  36  telescopically received in the outer leg section  34  and selectively extendable therefrom. A rubber foot  38  is disposed on the end of each inner leg section  36  and functions to improve stability and prevent skidding of the portable sign assembly  10 . As presently preferred, the inner leg section  36  includes a detent (not shown) for releasably holding the inner leg section  36  in an outwardly or fully extended position. The detent may comprise any number of mechanisms well known to those skilled in the art. An example of a preferred detent is illustrated and disclosed in U.S. Pat. No. 4,548,379 which is commonly owned by the assignee of the present invention and the disclosure of which is expressly incorporated by reference herein. 
     A support strap  42  may be secured to each leg assembly  30  on a side opposite to the base plate  16  for cooperating therewith to enhance the rigidity of the base assembly  12 . As previously described, each leg assembly  30  is pivotally coupled to a corresponding base plate  16  via a threaded fastener  32 . The leg assembly  30  further includes a leg release mechanism  50  disposed through an end of the outer leg section  34  and operable to engage the base plate  16  for positioning and releasably locking the leg assembly  30  in a retracted or stored position, or one of a plurality of protracted or deployed positions. 
     With particular reference to FIGS. 2 through 4, the leg release mechanism  50  includes a generally J-shaped lock-pin  52  and a leaf spring  54 . The lock-pin  52  includes first and second extensions or legs  56 ,  58  interconnected by an arcuate intermediary portion  60 . The first extension  56  is received through an aperture  62  formed in outer leg section  34  and extends into aperture  64  formed in base plate  16 . The second extension  58  is received through an aperture  66  formed in outer leg section  34 . The first extension  56  is slightly shorter than the second extension  58 . The first extension  56  has an ear  68 . 2  formed therein which engages the leaf spring  54  as best seen in FIG.  4 . The first extension  56  also has a second ear  68 . 4  formed therein. The second ear  68 . 4  functions as a stop or limit to the travel of lock-pin  52  by engaging the inner wall  34 . 2  of the outer leg section  34 . As presently preferred, aperture  62  has a radial slot  70  which allow ears  68 . 2 ,  68 . 4  to be received therein. Alternately, aperture  62  could be an oversized circular aperture. 
     A formed end cap  76  is affixed to the end of the second extension  58 . End cap  76  provides an enlarged kick surface area  78  for an operator to position the lock mechanism  50  between the locked and released position. It should be noted, however, that the end cap  76  is optional, and force may be applied directly against the end of the first extension  56 . The end cap  76 , however, provides a larger target area for actuating the lock-pin  50 . 
     Lock-pin  52  is operably coupled to leaf spring  54 . Specifically, the second extension  58  is disposed through a slot  72  of the leaf spring  54  and is freely slidable relative thereto. A second slot  74  is also provided for passively receiving threaded fastener  32  therethrough. Ear  68 . 2  engages an outer surface  54 . 2  of leaf spring  54 . As presently preferred, the leaf spring  54  is formed from a substantially flat piece of stainless spring steel that has been formed to have a bowed configuration. The leaf spring  54  biases the lock-pin  52  in a first direction (indicated by arrow A in FIG. 3) for locking the leg assembly  30  relative to the base plate  16 , as described in further detail herein. 
     The lock-pin  52  is adapted to slide in a direction generally perpendicular to the longitudinal axis of the leg assembly  30  so as to be received into one of a plurality of apertures  76 . 2 ,  76 . 4 ,  76 . 6  formed through the base plate. In this manner, the leg assembly  30  may be locked into multiple positions. When the lock-pin  52  is received into the aperture  76 . 2 , the leg assembly  30  is oriented at approximately three degrees (3°) downwardly from a horizontal as defined by a bottom edge of the base plate  16 . The aperture  76 . 4  is formed in the base plate such that the leg assembly  30  is oriented at approximately fifteen to twenty degrees (15°-20°) downwardly from the horizontal. In this manner, a degree of adjustability is provided for placing the portable sign assembly  10  on an irregular (i.e. non-flat) surface. The third aperture  76 . 6  is formed in the base plate  16  and oriented such that the leg assembly  30  may be locked in a retracted position for compact storage. 
     With continued reference to FIGS. 2 through 4, operation of the leg release mechanism  50  will be described in detail. In a first, locked position, the leg assembly  30  is pivotally positioned about the threaded fastener  32  such that the lock-pin  52  is aligned with the aperture  76 . 2 . The leaf spring  54  biases the lock-pin  52  in the direction of arrow A (as viewed in FIG.  3 ), whereby an end of the first extension  56  extends into the aperture  76 . 2  and engages the base plate  16 . The ear  68 . 4  functions as a stop or limit for further movement of the lock-pin. In this position, the leg assembly  30  is prevented from further rotation about the threaded fastener  32 , and thus releasably locked into the protracted position. 
     To move the leg assembly  30  into an alternate position, such as the retracted position, the lock-pin  52  is urged against the bias of the leaf spring  54  by pulling on the arcuate intermediary portion  58  or alternately pushing on the end cap  76  whereby the end of the first extension  56  is withdrawn from engagement with the aperture  76 . 2 . As the lock-pin  52  disengages the base plate  16 , the leaf spring  54  is compressed to a point where it is pressed substantially flat against an inner surface of the outer leg section  34 . With the lock-pin  52  in this position, the leg assembly  30  may be pivotally positioned about the threaded fastener  32  with respect to the base assembly  12  and moved to a point where the lock-pin  52  is aligned with an alternate aperture such as apertures  76 . 4  or  76 . 6 . 
     In an alternative embodiment, as shown in FIGS. 5 and 6, a lock-pin  152  may include a generally J-shaped member having first and second extensions  156 ,  158  interconnected by an arcuate intermediary portion  160 . The second extension  158  of lock-pin  152  is shorter than second extension  58  of lock-pin  52  so as to remain within the interior volume outer leg member  34  when the lock-pin  152  is in the extended position. The leaf spring  54  is identical to that previously described. The first extension  156  is generally longer than the second extension  158  and extends through the leg assembly  30 . The first extension  156  includes a circumferential groove  168  for engaging the leaf spring  54  and is disposed through a first slot  72  of the leaf spring  54 , whereby corresponding edges of the first slot  72  engage the grooves  168 . The second extension  158  is disposed through the first slot  72  of the leaf spring  54  and is freely slidable relative thereto. The free end of the second extension  158  engages the inner wall  34 . 2  of outer leg member  34  to provide a stop or limit to the travel of lock-pin  152 . In general, operation of the alternative embodiment parallels that described hereinabove. 
     The present invention greatly simplifies the assembly of the leg release mechanism  50  into the leg assembly  30  over other prior art devices. The lock-pin  52  is insert completely through apertures  66 ,  70  of the leg assembly  30 , whereby the first extensions  56 ,  58  simultaneously are received into the leg assembly  30 . The use of a single lock-pin having a pair of legs eliminates the need to align and couple multiple pieces of conventional lock-pin assemblies. The lock-pin  52  is then held in the extended position. Spring  54  is positioned axially into the interior volume defined by the sidewalls of outer leg section  34 . Extensions  56 ,  58  are received within slot  72  and ear  68 . 2  is located on the outer surface  54 . 2  of leaf spring  34 . Spring  54  is preloaded or compressed slightly to position the spring on the underside of ear  68 . 2 . Once properly located, spring  54  and ears  68 . 2 ,  68 . 4  cooperate to hold the spring in proper orientation and to bias the lock-pin toward the extended position. 
     As presently preferred, lock-pin  52 ,  152  is formed by bending a constant cross-section piece (e.g. ⅜″ wire stock) to form a generally J-shaped pin. In the case of the first preferred embodiment, the ears  68 . 2 ,  68 . 4  may be swaged into lock-pin  52  during the bending operation to provide an engagement element having a diameter that is greater than the nominal diameter of the lock-pin  52 . In this way, a very inexpensive component of the lock mechanism  50  is fabricated. In the case of the second embodiment, slot  168  is machined into lock-pin  152  in a post-bending operation to provide an engagement element having a diameter that is less than the nominal diameter of the lock-pin  152 . 
     The assembly of leg release mechanism  150  is similar to that previously described with respect to leg release mechanism  50  with the following differences. The second extension  158  of lock-pin  152  is partially received into the outer leg member  34 . Leaf spring  54  is operably coupled to lock-pin  152  by locating leaf spring  54  in groove  168 . Once properly positioned, leaf spring  54  and the free end of second extension  158  cooperate to hold the leaf spring  54  in the proper orientation and to bias the lock-pin  152  toward the extended position. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.