Abstract:
A locking system for a telescopic seating system is disclosed. The system provides a means to releasably lock adjacent telescopic seating platforms together and a means to release the locking mechanism without the need for a trip bar or other like device. The locking system employs a low profile tier catch and tier catch ramp that promotes ease of use and a reduction in the possibility of damage due to individuals walking over the locking device.

Description:
This application is a continuation of application Ser. No. 09/668,238, filed Sep. 23, 2000, now abandoned, which claims the benefit of Provisional application Ser. No. 60/156,118, filed Sep. 25, 1999. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to telescoping seating systems. More particularly, the invention relates to tier catches for releasably locking telescopic seating platform sections. 
     BACKGROUND OF THE INVENTION 
     Conventional telescopic seating systems are compilations of individual repeatable segments known as platforms or decks. A single platform is comprised of the following components. A rear riser beam that runs transversely along the length of the deck forms the main carrying support for the platform and is situated at the back of the platform. The rear riser beam is typically a continuous rectangular piece of steel with the width of the riser having a vertical orientation relative to a substrate such as a floor on which the seating system is placed. The riser is fabricated with a rear flange that extends from a bottom end of the riser toward the front of the platform. The flange provides a surface for mounting other components of the platform. 
     Situated at the front of the platform is a nose beam that defines the front edge of the platform. The nose beam is typically fabricated from extruded aluminum, tube steel or shaped into a partial tube from sheet steel. The top front edge of the nose beam is radiused to provide comfortable seating conditions if no further seating components are added to the platform. Nose beams constructed from extruded aluminum or sheet steel formed into a partial tube lacks the strength of a tube steel design but is far less expensive to manufacture. There is thus a need for a nose beam that has the strength of a tube steel design but which is cost efficient relative to the sheet steel open design. 
     Extending toward the back of the platform from the nose beam is a front flange that provides a mounting surface for further components of the platform. The front flange can be either a separate bar of steel welded onto the nose beam or a continuation of the sheet steel that forms the main body of the nose beam. Structural steel is the material of choice for the rear riser beam and the nose beam since these components are required to withstand the application of significant loads along their lengths. Of course, any durable material that is capable of withstanding the compression and tension forces imparted onto the beams can be utilized for these components. 
     The rear riser beam and nose beam are connected at their ends by a pair of lateral deck supports. The deck supports can be either bolted to or welded onto the transverse riser and nose beams. The rear riser beam and nose beam are also connected by deck supports situated between the lateral deck supports that are used to provide additional support for the decking material. The length of the particular deck determines the number of deck supports needed. Additional connections between the riser and nose beams are provided by cantilever sections of columns as described below. Both deck supports and cantilevers are made from formed steel. 
     The combination of the deck supports, the rear flange and the front flange provide a mounting surface for decking material which forms the surface to which further seating components are attached or upon which individuals sit. Almost invariably, plywood-based materials are used for the decking. In fact, the industry-standard 4×8 feet sheet plywood is used which in turn, sets the standard for platform depths. In the conventional application, 4×8 sheets of a multi-ply plywood product are ripped along its length to produce two 2×8 feet sections. The platform frames to which the plywood sections are attached are sized to accommodate the 2×8 sheets. Platforms are typically 26 inches deep. 
     To establish the height of a platform to a selected height, columns are provided, typically in pairs, which attach to the rear riser. Conventional columns for telescopic seating systems are constructed from tube steel because of the tube steel&#39;s ability to withstand the multitude of forces applied to the platform when a load is applied. 
     Situated at or near the top ends of the columns are cantilevers, which extend toward the front of the platform. As stated, the cantilevers provide additional connections between the riser and nose beams. Formed within the cantilevers are linear channels or races for receiving roller wheels, which are attached to the tops of the columns. The channels are adapted to receive the column wheels of a platform that is immediately below and forward of the platform of which the channel forms a part thereof. By design, the mated wheels and channels are slidingly engageable. The wheels/channel assemblies provide a means for sliding adjacent platforms into either retracted/nested states or extended/used states. The cantilevers fully support the platforms in the retracted position. 
     The bottom ends of the columns are attached to castor horns. The castor horns provide a mounting base for wheels, which allow for the transitional movement of a platform from a retracted position to an extended position and vice versa. The castor horns are also typically made of steel and have features, which allow for the connection of adjacent castor horns that are part of adjoining platforms such as hooks that are adapted to be received in channels. Adjacent castor horns are adapted to be capable of sliding engagement with one another and are further capable of being releasably locked together when adjacent platforms are in an extended orientation. Castor horn engagement is provided by mating surfaces that do not extend the length of the castor horns. 
     To counter the various compression, tension and torque forces exerted on platform segments when placed under load, cross bracing is used. The braces are configured to attach a top end of a first column at a first end of a platform to the bottom end of a second column at a second end of the platform. Multiple cross bracing members can be used depending on the specific size and set up of a series of platforms which are joined to form telescopic seating systems. 
     A problem encountered with conventional telescopic seating systems is the means used to lock adjacent sections together when the telescopic seating system is partially or fully extended. Prior systems incorporate a lever lock that projects above the caster horn in conjunction with a trip bar typically located on the first row. An external handle or other device has to be used to activate the trip bar. As is well known in the art, individuals that use telescopic seating systems occasionally attempt to walk under the extended platforms to facilitate ingress or egress from the particular location. When negotiating through the maze of columns and caster horns, individuals often step on the caster horn lock mechanisms, especially the long lever arms protruding vertically. Due to the fragile design of the locks, damage and lock malfunction often result. Trip bar angles, which have to be precisely set often, have to be adjusted due to abuse. There is thus, a need for a lock system that is capable of withstanding physical abuse and maintaining full operational capability. In addition, there is desire to eliminate the trip bar which has to be precisely set to trip each lever lock at the correct time. 
     It is thus an object of the invention to provide a caster horn locking mechanism that eliminates the need for a trip bar and that withstands the abuse of individuals walking onto the locks without compromising the integrity or function of the lock. These and other objects and features of the invention will be understood from a review of the following description and drawings. 
     SUMMARY OF THE INVENTION 
     The invention described herein is a locking mechanism used to releasably lock adjacent platform sections together when in an extended orientation. The locking mechanism is designed to be self-engaging in that the need for a trip bar to initial telescopic seating retraction is eliminated. The locking mechanism is comprised primarily of a tier catch mounted on the outer side of a castor horn. The tier catch has a series of flanged surfaces for engaging an end guide of an adjacent castor horn to lock the castor horn to the adjacent castor and for tripping other tier catches when moving toward a nested or retracted position. 
     A tier catch tab is provided to act as the tripping component to trip other tier catches. Rear flanges are provided on the tier catches to allow for adjacent tier catches to nest when in an unlocked retracted position. 
     To promote the stability of the tier catches in a vertical unlocked position, a tier catch ramp is affixed to a castor horn side opposite that to which the tier catch is attached. The catch ramp acts as a physical support for a vertical unlocked tier catch to ensure damage is not imparted to the tier catch if a focused load, e.g., a person&#39;s foot, is placed on the tier catch in an unlocked position. 
     The tier catch has an additional flange on an uppermost edge that provides a means for facilitating tier catch rotation into a vertical position past adjacent cantilevered columns. These and other features of the tier catch castor horn locking system will become apparent from a reading of the following detailed description in view of the drawings appended hereto. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a telescopic seating system in accordance with one embodiment of the invention. 
     FIG. 1 a  is a side perspective view of a platform support assembly according to one embodiment of the invention. 
     FIG. 2 is a side perspective view of a plural platform support assembly according to one embodiment of the invention. 
     FIG. 3 is a perspective view of a castor horn lock assembly according to one embodiment of the invention. 
     FIG. 4 is a left side perspective view of a plural platform support assembly according to one embodiment of the invention. 
     FIG. 5 is a right side perspective view of a plural platform support assembly in full extension according to one embodiment of the invention. 
     FIG. 6 is a left side perspective view of a castor horn lock assembly in a locked position according to one embodiment of the invention. 
     FIG. 7 is a right side perspective view of a castor horn lock assembly in a locked position according to one embodiment of the invention. 
     FIG. 8 is a left side perspective view of a plural platform support assembly in a semilocked position according to one embodiment of the invention. 
     FIG. 9 is a right side perspective view of a plural platform support assembly in a closing and unlocking position according to one embodiment of the invention. 
     FIG. 10 is a top left perspective view of a castor horn lock assembly in a closing and unlocking position according to one embodiment of the invention. 
     FIG. 11 is a top right perspective view of a castor horn assembly in a closing and unlocking position according to one embodiment of the invention. 
     FIG. 12 is a left side perspective view of a plural platform support assembly in an unlocked and closing position according to one embodiment of the invention. 
     FIG. 13 is a right side perspective view of a plural platform assembly in an unlocked and closing position according to one embodiment of the invention. 
     FIG. 14 is a top left perspective view of a castor horn lock assembly in an unlocking position according to one embodiment of the invention. 
     FIG. 15 is a top right perspective view of a castor horn lock assembly in an unlocking position according to one embodiment of the invention. 
     FIG. 16 is a top front perspective view of a castor horn lock assembly according to one embodiment of the invention. 
     FIG. 17 is a top front perspective view of a castor horn assembly according to one embodiment of the invention. 
     FIG. 18 is a top front perspective view of a castor horn assembly according to one embodiment of the invention. 
     FIG. 19 is a backside perspective view of a castor horn assembly according to one embodiment of the invention. 
     FIG. 20 is a left perspective view of a plural platform support assembly in an unlocked, closing position according to one embodiment of the invention. 
     FIG. 21 is a right perspective view of a plural platform assembly in an unlocked, closing position according to one embodiment of the invention. 
     FIG. 22 is a top left perspective view of a castor horn lock assembly in an unlocked, closing position according to one embodiment of the invention. 
     FIG. 23 is a top right perspective view of a castor horn lock assembly in an unlocked, closing position according to one embodiment of the invention. 
     FIG. 24 is a side elevational view of a plural platform support assembly in an extended position according to one embodiment of the invention. 
     FIG. 25 is a side elevational view of a plural platform support assembly in a partially retracted unlocking position according to one embodiment of the invention. 
     FIG. 26 is a side elevational view of a plural platform support assembly in a retracted unlocked position according to one embodiment of the invention. 
     FIG. 27 is a side elevational view of a castor horn lock assembly in a locked position according to one embodiment of the invention. 
     FIG. 28 is a side elevational view of a castor horn lock assembly in a partially unlocked position according to one embodiment of the invention. 
     FIG. 29 is a side elevational view of a castor horn lock assembly in an unlocked position according to one embodiment of the invention. 
     FIG. 30 is a front elevational view of a plural platform support assembly in a locked position according to one embodiment of the invention. 
     FIG. 31 is a front elevational view of a plural castor horn assemblage in a locked position according to one embodiment of the invention. 
     FIG. 32 is a side perspective view of a plural platform support assembly in a retracted unlocked position according to one embodiment of the invention. 
     FIG. 33 is a side perspective view of a castor horn and castor horn lock assemblage in a retracted unlocked position according to one embodiment of the invention. 
     FIG. 34 is a right side perspective view of a plural platform support assembly in a nested and unlocked position according to one embodiment of the invention. 
     FIG. 35 is a side perspective view of a castor horn and castor horrn lock assemblage according to one embodiment of the invention. 
     FIG. 36 is a side perspective view of a plural platform support assembly in a partially retracted, unlocked position according to one embodiment of the invention. 
     FIG. 37 is a topside perspective view of a castor horn and castor horn lock assemblage in a partially retracted, unlocked position according to one embodiment of the invention. 
     FIG. 38 is a left side perspective view of a plural platform support assembly in a retracted and unlocked position according to one embodiment of the invention. 
     FIG. 39 is a left side perspective view of a castor horn and castor horn lock assemblage in a retracted unlocked position according to one embodiment of the invention. 
     FIG. 40 is a side elevational view of a tier catch according to one embodiment of the invention. 
     FIG. 41 is a front elevational view of a tier catch according to one embodiment of the invention. 
     FIG. 42 is a side perspective view of a tier catch according to one embodiment of the invention. 
     FIG. 43 is a top view of a tier catch according to one embodiment of the invention. 
     FIG. 44 is a top plan view of a tier catch tab according to one embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     At the outset, the invention is described in its broadest overall aspects with a more detailed description following. Referring to FIG. 1, a telescopic seating system, referred to generally as  1 , is shown which comprises a plurality of platforms referred to generally as  2 . Platforms  2  are engaged to each other such that each can slide in relation to adjacent platforms to allow for the retraction of the seating system into a nested or unused state and for the extension to an extended or operational state. 
     Before describing the general structure of the platforms, nomenclature will be addressed. As used herein, a first row modular unit is a platform capable of bearing loads that extends partially along the width of a telescopic seating system. A standard row unit is a platform capable of bearing loads that extends along the entire width of a telescopic seating system. 
     Each standard row unit, addressed simply as a platform herein below, comprises the following components. A rear riser beam  3  situated at the back of the platform and a nose beam  4  situated at the front of the platform dictate the overall length dimensions of the platforms. The rear riser beams  3  are oriented to extend upwardly on an edge to establish part of the height of the platforms and to provide mounting surfaces for other components of the platform. The nose beams  4  are preferably tubular steel structures that also have mounting surfaces for other components of the platform. 
     Deck stabilizers  5  and cantilevers  120  (shown in FIG. 1 a ) attach the rear riser beams  3  and nose beams  4 . The deck stabilizers  5  connect the ends of the rear riser beams  3  to the ends of the nose beams  4 . The cantilevers  110  are horizontal extensions of columns  6  that are provided to establish the height of the platforms  2 . Each platform  2  has at least two columns  6 , which set the height and carry the loads placed on the platforms. The columns  6  are biased toward the lateral edges of the platforms  2  and may be canted inwardly at their tops to better withstand load placed on the platforms as described in U.S. Pat. No. 4,041,655 to Pari. 
     The combination of the deck stabilizers  5 , the nose beams  4  and the rear riser beams  3  provide a mounting surface for decking  8 , which is typically made from plywood. The plywood decking provides a surface for mounting additional seating components such as seats  9  and provides a substrate for stepping from one platform to another. 
     Attached to bottom ends of the columns are castor horns  25   a , which have channels, provided therein for receiving roller wheels  30 . The castor horn/roller wheel assemblies allow for the linear movement of platforms from an extended to a retracted position and vice versa. These features are found on all platforms. 
     Referring now to FIGS. 1 a - 44 , a low profile lock system also known as a tier catch, referred to generally as  200 , is shown in various stages of locked to unlocked positions. As shown in FIGS. 4,  5 ,  8 ,  9 ,  12 ,  13 ,  19   a ,  19   b ,  20 ,  21 ,  24 - 26 ,  32 ,  34 ,  36  and  38 , lock system  200  is shown in relation to platform frame subassemblies shown generally as  100 . Platform frame subassemblies  100  comprise columns  110  which have cantilevers  120  which extend substantially perpendicular to the longitudinal axis of columns  110 . Cantilevers  120  have a nose attachment plate  125  provided at a front end of cantilevers  120  for receiving a nose beam  4 . 
     Riser attachment plates  130  for attaching a rear riser beam (not shown) are provided at or near a top end of columns  110 . Columns  110  are attached to caster horns  400  which have channels  450  formed therein (as shown in FIGS. 16-19) for receiving wheels  460  which allow for the movement of platform subassemblies  100 . 
     Attached to a front end of castor horn  400  is end stop plate  470  which arrests movement of one platform frame subassembly  100  from moving past an adjacent platform frame  100  that is positioned behind the one platform frame subassembly  100 . End stop plate  470  ensures that adjacent platforms or rows will be nested in a substantially vertical orientation to optimize space utilization when in a fully retracted position. 
     Attached to a first side of caster horn  400  at approximately the location of a front edge of column  110  is tier catch  210 . As shown in FIG. 1 a , tier catch  210  is attached to caster horn  400  with a pin or bolt  215  such that tier catch  210  can freely rotate about pin  215 . In a preferred embodiment, tier catch  210  has a threaded nut  222  affixed via welding or other suitable attachment means to a distal arm  221  as shown in FIGS. 40,  41 ,  43  and  44 . Nut  222  preferably has a thick cylindrical outer diameter that is preferably equivalent to the diameter of bolt  215 . Such a combination creates two bearing surfaces that eliminates or at least reduces lateral slop and play in tier catch  210 . Preferably, Locktite® is added to prevent bolt/nut disengagement. The combination of bolt  215  and nut  222  act as a hinge upon which tier catch  210  pivots. Optionally, washers, preferably nylon, can be placed on bolt  215  between the head of bolt  215  and castor horn  400  and between nut  222  and castor horn  400  to minimize friction and eliminate the need for oiling the rotating surfaces. 
     Tier catch  210  has a tier catch body  211  that is a flat piece of steel shaped to form a hook  216  (shown in FIG. 40) that is adapted to engage and releasably lock an end guide  230  of an adjacent caster horn  400  as described in more detail below. Tier catch  210  has a catch release strike plate  212  at a front end of tier catch  210  that is oriented substantially perpendicular to the plane occupied by tier catch body  211 . Attached to a side of tier catch body  211  that is opposite the side adjacent to column  110  is tier catch tab  220 . Tier catch tab  220  is adapted to contact tier catch  210  on an adjacent caster horn  400  when adjacent platforms are retracted so that tier catch  210  is released from a locked position relative to a third caster horn  400  that has the end guide  230  onto which the subject tier catch  210  was locked. Tier catch tab  220  can be made integral to tier catch  210  in a casting process or welded onto tier catch  210 . If welded, tier catch  210  is provided with tab locating holes  225  and catch tab  220  is provided with locating tabs  226  (FIG.  45 ). Catch tab  220  is preferably oriented at a 90° angle to the plane occupied by tier catch body  211  as shown in FIG.  41 . 
     Tier catch body  211  has a top section  228  that is canted to the side away from catch tab  220 . This ensures that tier catch  210  will pass freely by adjacent canted column  110  when rotated into a vertical unlocked position. 
     Attached to a second side of caster horn  400  is tier catch ramp  240 . Tier catch ramp  240  has a sloped section  241  which is adapted to receive and support tier catch  210  when tier catch  210  is modulated from an operable/locked position to an inoperable/unlocked position, i.e., when tier catch  210  is rotated upwardly about pin  215  when adjacent caster horns  400  and their associated decks or platforms are placed in a nested or fully retracted position. Catch release strike plate  212  has a rear flange or trailing edge  213  which is angled from about 7° to about 18° and preferably about 12° from horizontal when tier catch  210  is in a down or locked position. The incline of the angle is opposite that of catch release strike plate  212 . Rear flange  213  allows for adjacent catch tiers  210  to nest when in an unlocked or up position, i.e., when the seating system is in a retracted position. 
     Situated near the front end of caster horn  400  is end guide  230 , which is shaped to substantially conform to the shape of a right angle. A first arm  231  of end guide  230  is attached to a second side of caster horn  400  with mechanical fasteners (not shown), which are threaded or placed into one of a series of apertures formed in the second side of caster horn  400 . The particular placement of end guide  230  determines the depth of the rows or platforms for a given telescopic seating system. To adjust the depth, end guide  230  is placed into a different selected aperture on the second side of caster horn  400 . A second arm  232  of end guide  230  is adapted to be suspended above a top surface of an adjacent caster horn  400 . 
     In order for catch release strike plate  212  to engage and unlock an adjacent tier catch  210  via engagement with tier catch tab  220 , the angles to which the contacting surfaces are set must fit within certain ranges in order for the unlocking process to be successfully accomplished. Catch release strike plate  212  has to be angled forward, i.e., canting forward from a bottom end to a top end of strike plate  212 , from about 5° to about 20° and preferably from about 10° to about 15°. Tier catch tab  220  must be angled down going from a back end to a front end of tier catch tab  220  from about 5° to about 20° and preferably from about 10° to about 14° and most preferably at about 12°. 
     To operate lock system  200 , the platforms are pulled out from a nested position so that adjacent caster horns  400  slide into an extended position. When the a tier catch  210  of a first castor horn  400   a  is pulled toward the end guide  230  of a second caster horn  400   b , tier catch  210  of first caster horn  400   a  slides over and engages a front edge of end guide  230  of second caster horn  400   b  which locks the two castor horns together. This, in turn, locks adjacent platforms or decks into a set position. 
     To unlock the tier catch/end guide assembly, a tier catch tab  220  on tier catch  210  of a third caster horn  440   c  (which is situated on a side of first caster horn  400  that is opposite the side to which second castor horn  400   b  is adjacent), contacts strike plate  212  on tier catch  210  of first caster horn  400   a  when third caster horn  400   c  is slid toward a retracted or nested position. Tier catch  210  of first caster horn  400   a  is rotated upwardly about pin  215  so that hook  216  is disengaged from end guide  230  of second caster horn  400   b.    
     Utilization of this system of tier catches, end guides and release strike plates eliminates the need for trip bars as used in conventional systems. The lock system of the present invention also eliminates the need for external devices to operate the trip bars. 
     Turning to FIG. 30 and 31, a plurality of assembled caster horns are shown. Referring specifically to FIG. 30, a plurality of caster horns  400  are shown attached to columns  110  which each have a riser support plate  130  and nose plates  125  as previously described. Referring specifically to FIG. 31, caster horns  400  have caster horn bodies  410  which has portions defining a J-hook  420  on a first side of caster horn body  410 , which preferably extends along the entire length of caster horn body  410 . J-hook  420  forms a channel for receiving a knee hook  430  of an adjacent caster horn  400 . 
     Caster horn body  410  has further portions, which define knee hook  430  on a second side of castor horn body  410 , which preferably extends along the entire length of castor horn body  410 . Knee hook  430  can extend as little as 10% of the length of castor horn body  410 . However, to provide maximum support for castor horn alignment, knee hook  430  has to extend the entire length of caster horn body  410 . 
     J-hook  420  and knee hook  430  are adapted to mate in sliding engagement. To assemble or interlock castor horns, the J-hook  420  of one caster horn  400  is mated with the knee hook  430  of an adjacent caster horn  400  by either placing knee hook  430  into the channel formed by J-hook  420  or by sliding one into the other from the ends of the caster horns  400 . The mating surfaces ensure that adjacent caster horns  400  are maintained in a parallel orientation when a telescopic seating system is in any position between full retraction and full extension. Fully interlocked castor horns which have J-hooks  420  and knee hooks  430  that run the entire length of the castor horn bodies  410  provide maximum resistance to the pivotal movement of individual castor horns from a parallel orientation that is caused by the lateral movement of columns  200  when under load. Unlike prior art systems, the fully interlocked caster horns  400  of the present invention resist castor horn pivotal travel at all possible positions of telescopic seating system retraction and extension. 
     Having described the invention it should be understood that the foregoing description of the invention is intended merely to be illustrative thereof and that other modifications, embodiments and equivalents may be apparent to those who are skilled in the art without departing from its spirit.