Патент USA US3088186код для вставки
May '-7, 1963 G. A. DELF ET AL 3,088,176 FOLDING BLEACHER ATTORNEYS May 7, 1963 G. A. DELF ETAL 3,088,176 FOLDING BLEAGHER Filed May 5, 1960 A ` 2 Sheets-Sheet 2 73 0 FIGA. INVENTORS C-:EORGE A. DîLF' ROBERT E. KQRTUM BYCOMM'PMMQQ ATTORNEYS United States Patent Óíi?ce 3,088,176 Patented May 7„ 1963 2 ma mined by a closed or lowered position of the hinged seat 3,083,176 FOLDING BLEACHER apron on the lowest seat «frame when such lowest seat frame is fully retracted relative to the tallest frame, there by precluding unintentional extension of any seat frame. An important object is to provide a seating structure that is simple and durable in construction, economical to manufacture, eflicient in operation, and which can be ' George A. Delf, St. Louis, and Robert E. Kortum, Robert son, Mo., assâguors to Narragansett Gymnasium Equip ment Company, St. Louis, Mo., a corporation of Missouri Filed May 5, 1950, Ser. No. 27,053 9 Ciaims. (Cl. Ztl-1.126) readily manipulated between extended and retracted posi tions by anyone. The foregoing and numerous other `objects and vadvan This invention relates generally to improvements in seat 10 tages of the invention will more clearly appear from the ing structures, and more particularly to improvements in following detailed description of a preferred embodiment, the construction and operation of bleacher seats `of `the particularly when considered in connection with the ac retractile or foldable type especially adapted for use in companying drawings, in which: gymnasiums, auditoriums and the like. FIG. 1 is a side elevational View of the seating structure Various types of folding bleacher structures have here 15 when disposed in a fully retracted position; -tofore been proposed for use -in gymnasiums, arenas and FIG. 2 is a side elevational view Vof the seating structure similar places where it is desirable to conserve floor space with the lowest seating frame partially extended; at times while utilizing maximum seating capacity at other times. Although some of the folding `or telescopic bleacher assemblages heretofore proposed have enjoyed a fair degree of commercial success, considerable dif ficulty has lbeen encountered in providing unitary struc -tures which are adapted to be folded or telescoped in a simple manner by a single individual without need for special equipment, and which form a neat land compact, substantially enclosed un-it when not in use. It is an important object of the present invention to FIG. 3 is a side elevational View of the seating structure 20 fully extended, and FIG. 4 is a rear elevational view of the seating struc ture when retracted. Referring now by characters of reference -to the draw ings, and íirst to FIGS. l-3 inclusive, it is seen that the seating structure includes a plurality of successive trans verse frames indicated at 1t), 11 and 12 of gradually decreasing heights. In the embodiment disclosed, there are a total of three frames, but it will be readily apparent provide yan improved retractable bleacher assembly which that any suitable number may be utilized depending upon obviates all of the previously mentioned disadvantages 30 preference and field of usage. The frames 11 and 12 con heretofore attendant devices of this general type. structed so that they can be selectively nested below and An important objective is to provide an improved within each adjacent taller frame as is illustrated in FIG. unitary bleacher structure having a series of intercon l or be selectively extended as is shown in FIG. 3. nected -seating rows comfortably spaced and `arranged in The tallest frame 16 includes a plurality lof laterally tiers when extended, and adapted to be quickly and easily 35 telescoped or folded to compact nested -arrangement with a lminimum of eñort when desired. Another important objective is achieved by the provi sion of improved latching mechanism interconnecting `the spaced base members 13 -that normally seat on a sub jacent surface such as -a floor. Usually, lthe tallest seating frame 10 is located with its rear against a vertical Wall and the base members 13 extend forwardly therefrom. telescopically rel-ated seat frames which positively locks 40 A plurality of vertically extending posts 14 are attached to and carried by base members 13. Attached lto the the frames in extended position, and which selectively posts 14 is a forwardly extending horizontal support 15. unlocks the frames to permit sequential retraction. Mounted on the top of posts 14 and extending transversely Other important advantages Iare realized in that the of the frame 1t) is a seat 16 formed by a long plank. latching mechanism is conditioned to enable retraction of the extended frames upon raising ya hinged seat apron 45 Depending from the front edge of top seat 16 -is a seat apron 17 extending transversely of the frame 10. on the lowest frame, and the latch interconnecting each The tallest frame 1t) is provided with an inverted adjacent pair of frames is unlocked -automatically upon U-shaped channel 26 that is fixed to the front -of support retraction, while lowering the apron allows locking of Still another important object is achieved by providing a toggle interconnecting adjacent 'se-ating frames which 15 Vand extends transversely of frame 10 along the top of such support 1S. This channel 20 provides a mounting for the longitudinal seat 21 and its depending yapron 22. actuates a latch between its taller associated frame and For reasons which will later appear, one flange 23 of Asequential operation. channel 2@ extends downwardly below the horizontal lsupport 1S fora short distance. Yet another important objective is realized by provid 55 A panel 24 formed by a longitudinal channel is `se cured vto posts 14 and extends transversely of frame 10. ing a lever pivotally mounted on the lowest seating frame, the next taller adjacent frame »incident to movement of its lower associated frame. one end of which engages a hinged seat rapron -and the The panel 24 extends substantially from the bottom edge of seat apron 17 downwardly to the region just `above other end being connected operatively to a latch mecha support 15. The panel 24 cooperates with seat apron 17 nism between the lowest frame and the next taller frame. Upon lifting the seat apron, the lever acts to unlock the 60 to provide a rear closure. In addition, ya foot rest 25 formed by lan elongate plank latch when the frames are extended and hence enables is mounted on the forwardly extend-ing horizontal support retraction, while lowering the apron allows locking of 15 and is located between the rear panel 24 and the front the latch when the frames are moved to their extended seat 21. arrangement. The middle frame 11 is constructed somewhat similarly Another important object is afforded by providing a 65 spring connected »to the lever which tends to urge the lever in a direction to cause unlocking of the latch be tween the lowest seating frame and the next taller frame automatically upon lifting of the hinged seat apron. to the tallest frame 10 except that it only has a forward seat portion and is constructed of 1a height so that «it fits under the horizontal `support 15 of such taller frame 10. More particularly, the middle frame 11 lincludes a plural Still another important advantages are realized by providing a stationary stop that is adapted to engage the lever when the lever is disposed in a position as deter rollers 27. The base members 26 ‘are slid-ably related to ity Vof laterally spaced base members 26 mounted on the adjacent base members 13 of the highest frame 10 3,088,176 3 and are located inwardly thereof. The rollers 27 enable the middle iframe 11 to ‘be easily land quickly extended or retracted relative yto the adjacent taller frame 10. Similar to the above structure described with respect to the taller frame 10, the middle frame 11 includes a plu rality of upstanding posts 35 mounted on base members 26. As explained previously, the posts 30 extend upward 4 57 to posts 42 for vertical reciprocating movement with in limits upon oscillating movement of lever 53. A plate 4'60 is attached to posts 42 behind the panel 51 and extends upwardly above and behind the lower de pending margin of channel ñange 35 to provide an abut ment 61. Upon extending the lowest seating frame 12 relative to the next taller trarne 11, the abutment 61 en gages the channel flange 35 and limits such extension, and in addition, transmits the outward pulling force to the ly to a point just below the horizontal support 15 of the taller frame 10 to enable the middle frame 11 to be tele scoped within. The middle frame 11 includes a forward 10 frame 11 to cause extension of such frame 11 relative to the tallest frame 10. ly extending horizontal support 31 attached to and carried Cooperating with the -abutment 61 is a latch 62 that by the posts 30. Annother inverted U-shaped channel is pivotally connected to the horizontal support 31 of the 32 is secured to the upper front portion of horizontal sup next taller frame 11. When in the relatively extended port 31 and provides a mounting for a transverse seat 33 and its depending front Áapron 34. Again, it will be 15 position of the adjacent pair of frames 11 and 12, the latch 62 rests on top of actuating rod 56 and engages the abut noted that the front ñange 35 of channel 32 extends down ment 61 to preclude relative retraction. When so latched, wardly below the horizontal support 31 to provide a the rod 56 is in its lowermost position `as determined by shoulder the purpose of which will be explained subse the particular disposition of lever 53 when the hinged A panel 36 extends transversely of middle frame 11 and 20 apron 47 is in its closed position, as is best illustrated in FIG. 3. is secured to the posts 3i), the panel 36 extending up A tension spring 63 constituting a reselient means is wardly from the support 31 substantially to the bottom attached to the horizontal support 43 and is attached to margin of seat apron 22 on the taller frame 10 to provide lever 53, the spring 63 tends to pivot the lever 53 in a a closure. Attached to the horizontal support 31 is .a transversely extending foot rest 37 located between the 25 direction to raise rod 56 toward an unlocked position. Such movement of lever 53 is normally restrained under panel 36 and the front seat 33. spring loading by engagement of the hinged seat apron Of course, the seating structure can be constructed of 47 with the lever end 54. any number of intermediate seating frames, all of which To release the l-atching means interconnecting the lowest will be constructed identically with middle frame 11, but of successively and gradually decreasing heights to enable 30 frame 12 and the adjacent taller frame 11, and hence permit relative retraction, the hinged apron 47 is raised nesting below and within the next adjacent taller frame. as is illustrated in broken lines in FîG. 3. The lever 53 Only a single intermediate frame 11 is disclosed in this is thereby released and the spring 63 causes the lever to embodiment for purposes of illustration and clarity. raise actuating rod 56 upwardly so that rod 56 lifts the The lowest seating frame 12 is constructed similar to the intermediate frame 11 with a few modifications. For 35 latch 62 above the abutment 61. The frames 11 and 12 are now unlocked> and can be relatively retracted by roll example, the lowest frame 12 includes a plurality of base ing the lowest frame 12 inwardly below the next taller members 40 slidably related to and located with the base frame 11. members 26 of the adjacent taller frame 11. Again, the The locking mechanism interconnecting the next ad base members 40 include a plurality of rollers 41 to facili jacent pair of frames 10 and 11 includes a latch ’64 tate extending and retracting the frame 12. A plurality of quently. vertical posts 42 are carried by the rear of base members pivoted to the forwardly extending horizontal support 15. A plate 65 is secured to vertical posts 30 behind the panel 36, the plate 65 including an abutment 66 that is adapted to engage the depending lower margin of chan the support 43 being attached to upwardly extending posts 45 nel ñange 23 to limit relative extension of frames 10 and 11, and which is adapted to engage the latch 64 when 44 attached to the front of base members 40. the frames 10 and 11 are extended so as to preclude rela An langle plate 45 is attached to the horizontal sup tive retraction. An actuating rod 67 constituting operat port 43 and is attached to the top of the front posts 44, ing means is slidably mounted by pins 68 to the posts the angle plate 45 providing a mounting for a transverse 30 for reciprocating movement within limits. seat 46. When the frames 10 and 11 are relatively extended, Hingedly connected to the front margin of seat 46 is 40,- the posts 42 terminating just below the horizontal support 31 of the next adjacent taller frame 11. Extend ing forwardly from posts 42 is a horizontal support 43, the latch ‘64 rests on top of actuating rod 67 and engages a depending front apron 47. The apron 47 is movable the abutment 66 to prevent relative retraction. The rod within limits from the closed position shown in full lines 67 is lowered to one limit as is illustrated in FIG. 3 by in FIG. 3 to the raised position illustrated in broken lines. When in the closed position, the seat apron 47 55 gravity to retain the latch 64 .as described. A toggle 70 consisting of pivotally interconnected arms can be selectively retained in such position by a lock 50. 71 and 72 is located at opposite sides of the frame 11.V The lowest seating frame 12 includes .a panel 51 formed The toggles 70 are interconnected by transverse equalizing by a channel which is attached to and extends between bars 73 and 74, bar 73 interconnecting the toggle arms 71 the rear posts 42. The panel 51 extends upwardly from the horizontal support 43'to the lower margin of seat apron 60 and bar 74 interconnecting toggle arms 72. The toggle arm 71 is pivotally connected to the rear vertical posts 42 34 on the adjacent taller frame 11. A foot rest 52 is of the lowermost frame 12 while the other toggle arm secured to the horizontal support 43 and is located be 72 is pivotally connected to the horizontal support 31 of tween the panel 51 and the front seat 46. the next taller frame 11. The latching mechanism between the lowest frame 12 Upon release of latch 62 and subsequent retraction of and the next taller frame 11 includes identical mechanism 65 -lower-most frame 12 relative to the next adjacent taller at each side of the seating structure. A detailed descrip frame 11, the toggle 70 at each side of the seating struc tionv of the mechanism at one side will suñ‘ice for the ture rotates to engage the actuating rod 67. More par other. ' ticularly, the toggle arm 72 moves upwardly to engage This latching mechanism includes av lever 53 pivotally 70 the lower end of yrod 67 and operates to raise the rod 67 mounted to the front posts 44. One end 54 of lever 53 to lift latch 64 out of the path of abutment 66. This un engages the back side of seat apron 47 when the apron latching operation occurs substantially upon complete re 47 is in its closed position. The other end 55 of lever traction of the lowermost frame 12 within the next taller 53 is attached to an actuating rod 56 constituting an op frame 11, and hence conditions the frame 11 for retrac erating means. The rod 56 is slidably mounted by pins 75 tion within the next taller frame 10. It is seen that this 3,088,176 5 -mechanism .provides for sequential retraction of the seat ing frames. A pair of toggles 75 operatively interconnects the ad jacent frames 10 and 11, one of the toggles 75 being lo 6 and hingedly raised. The lever 53 is pivoted under the loading of spring 63 to lift the actuating rod 56, and hence lift the latch 62 above the abutment 61. The lowest frame 12 can then be relatively retracted within the next taller frame 11. When frame 12 is fully retracted within the adjacent frame 11, the toggle 70 engages the actuating rod 67 to lift the l-atch 64 above the abutment cated at each side of the seating structure. Each toggle 75 includes pivotally interconnected arms 76 and 77. Toggle arm 76 is pivotally connected to the horizontal 66. Then, the frames 11 and 12 as a unit may be re support 15 of the tallest frame 10 while the other toggle tracted relative to the adjacent taller frame 10. When arm 77 is pivotally connected to the posts 30 of the next lower frame 11. Equalizing bars 80 and 81 extend trans 10 fully retracted, the hinged apron 47 is closed so that the lever arm 83 tits behind the angle plate 82 to lock the versely between and interconnect the toggles 75 at op frames in the retracted position. ‘1f desired, the hinged posite sides of the seating structure. More particularly, apron 47 can be retained in closed position by lock 50. bar 80 operatively interconnects toggle arms 76 while bar It is seen that the particular structure causes sequential 81 operatively interconnects arms 77. lt is an important function of the equalizing bars 73 15 operation of the interconnected seating frames upon be ing either extended or retracted. Furthermore, it is seen and 74 interconnecting toggles 70 and of equalizing bars that operation of the frames is controlled by a hinged seat 80 and 81 interconnecting toggles 75 to transmit equal apron 47 on the lowest frame 12 and that movement of forces to the opposite sides of the frames when being re each frame conditions the next taller frame for either re tracted or extended, thus assuring that the frames will move in a straight path without any binding action there 20 traction or extension. between, such as would occur if the frames could be Although the invention has been described by making detailed reference to `a single preferred embodiment, such detail is to be understood in an instructive, rather than in Lock means is provided to retain the frames in their any restrictive sense, many variants being possible with fully retracted position as is illustrated in FIG. l. An angle plate 82 constituting a fixed stop is secured to the 25 in the scope of the claims hereunto appended. We claim as our invention: door immediately below lever 53. An arm 83 is attached l. In a seating structure, a plurality of transverse to lever 53 and extends downwardly to interiit behind frames of decreasing heights, the lower frame being re angle plate 32 when the lever 53 is pivoted upon closing tractable toward or extensible from the next taller frame, the front seat apron 47. This action locks all of the frames in the retracted position. To release the frames, 30 an abutment on the lower frame, a latch movably mounted to the next taller frame and engaging the abut the hinged front apron 47 is raised and the lever 53` is cocked laterally. ment when the frames are extended to preclude retr-ac tion, a lever pivoted to said lower frame, means hinged 63 so that lever arm 83 is raised above the angle plate 82. to the lower frame and engaging one end of said lever, The lowest frame 12 can then be extended relative to the 35 and an operating means operatively connected to the next taller frame 11. other end of said lever and mounted on said lower frame It is thought that the operation and functional advan automatically pivoted under the loading of tension spring for movement within limits, the said latch being dis tages of the seating structure have become fully apparent posed in the path of said abutment to preclude retraction from the foregoing detailed description of parts, but for of said frames with the operating means in one limit, the completeness of disclosure the extension and retraction of the frames will be brieñy described. It will be assumed 40 operating means in another limit holding the said latch out of such path to enable retraction, said lever moving that the frames are relatively retracted and locked in such the operating means to said limits in response to move position, as is illustrated `in FIG. 1, `and that it is desired ment of said hinged means. to extend the frames to provide an operative seating structure. 2. ln a seating structure, a plurality of transverse First, the lock 50 is unlocked to release the hinged 45 trames of decreasing heights, the lower -frame being re tractable toward or extensible «from the next taller frame, front apron 47. Upon lifting of seat apron 47, as illus an abutment on the lower frame, a latch movably mounted trated in FIG. 2, the lever 53 is moved pivotally by to the next taller frame and engaging the abutment when spring 63 so that lock arm 83 clears angle plate 82 and the frames are extended, a lever pivoted to said lower so that actuating rod 56 raises latch 62 to clear the abut ment 61. The frame 12 can then be relatively extended 50 iframe, an actuating rod connected to one end »of said lever and slidably mounted on said lower 'frame for movement with respect to the next taller trame 11. within limits, the latch being disposed in the path of said As the lowest frame 12 is extended, the latch 62 rides abutment to preclude retraction of said frames with the over the abutment 61 and drops down upon actuating actuating rod in one limit, the rod in another limit hold rod 56, the rod 56 being `lowered by hingedly closing the seat apron 47. In this position, the latch 62 engages the 55 ing the latch out of such path to enable retraction, an apron hinged to said lower frame and engaging the other abutment 61 to preclude relative retraction of frames 11 end of said lever, resilient means connected to said lever and 12, and in addition, the abutment 61 engages the tending to pivot the lever in a direction to move the lower margin of channel ñange 35 to exert an outward actuating rod to the said other limit to unlock said latch, pulling force on the taller frame 11. As the intermediate frame 11 is extended relative to 60 said hinged apron in one position `moving the lever so that the said latch is locked, and said apron in another the next taller frame 10, substantially the same action position enabling the lever to pivot under loading of said takes place. lFor example, the latch 64 rides over the resilient means so that the said latch is unlocked by said abutment 66 and drops down on top of the actuating rod actuating rod. . 67, the rod 67 being lowered .because the toggle 70l has 3. In a seating structure, a plurality of transverse been moved out of the collapsed position upon relative 65 frames of decreasing heights, the lower frame being re extension of the frames 11 and 12. Furthermore, the tractable toward or extensible from the next taller frame, abutment 66 engages the lower margin of channel flanges an abutment on one of said frames, a latch movably 23 to determine the fully extended position. mounted to the next adjacent yframe and engaging the When the frames 16, 11 `and 12 are fully extended, and with the hinged seat apron 47 closed, the latches 62 and 70 abutment when the frames are extended, a lever pivoted to said lower frame, an operating means connected to one 64 preclude unintentional retraction. The hinged seat end of said lever and mounted on said lower frame for apron 47 can then be locked in its closed position by Ámovement within limits, the latch engaging the abutment lock 50 if desired. to preclude retraction of said frames with the operating To retract the seating frames from their fully extended position, the front seat apron 47 is unlocked by lock 50 75 means in one limit, the operating means in another limit 3,958,476. disengagingthe latch from the Vabutment to enable retrac tion, resilient :means connected to said lever Ytending to 'Pivot the lever in adirection to move the operating means to the said other limit to unlock said latch, an apron hinged to the hinged apron the said latch tion enabling lower frame and engaging the lever, said in one position holding the lever so that is locked, and said apron in another posi the llever to pivot under loading of said resilient means so that the said latch is unlocked by said operating means, a stop element on said lever, a Íìxed f_or retraction by unlocking ,the latching means normally holding said next taller yframe. Y 7. Aln Áa `seating structure, a plurality of transverse frames of successive.y decreasing heights, said frames ybeing retractable inne'stedrelation to the next taller frame and ‘selectivelyV extensible therefrom, a latch pivotally mounted to each frameexcept the lowest frame, an abut ment on each frame except the tallest frame engaging the latch on the next taller frame when the frames are ex tended so as to prevent retraction, a seat apron hinged stop shoulder, the stop element engaging the said stop to the lowest frame and movable within limits, an actuat shoulder when the frames are fully retracted and the -apron is moved to said one position in which the said ing rod slidably mounted on each frame except the tallest latch is normally locked so as to prevent extension of lever operatively interconnecting said hinged apron with the said actuating rod on the lowest frame for moving the .said frames. 4. `In a seating structure, a plurality of transverse frames of successively decreasing heights, said frames being re tractable in nested relation within and below the next taller frame and successively extensible therefrom, a latch movably mounted to each frame except the lowest frame, an abutment on each frame except the tallest »frame en gaging the latch on the next taller frame when the frames are extended so as to prevent retraction, means hinged to the lowest yframe and movable within limits, means frame and engaging the latch on the next vtaller frame, a latch associated with such rod out of locking relation to the abutment on the lowest «frame upon 4movement of said hinged apron to one of said limits, and a toggle in terconnecting each pair of adjacent frames, each toggle engaging the rod of its taller associated frame to move ,the latch of the next taller frame out of locking relation to its abutment as its lower associated frame is selectively retracted, the retraction of each frame conditioning the next taller frame for retraction by unlocking the latch operatively interconnecting the said hinged means with 25 normally holding `said next taller frame. the latch on the next taller frame for moving the said latch out of locking relation to the abutment on said lower 8. In a seating structure, a plurality of transverse frames Iframe upon movement of said hinged means to one of of decreasing heights, each frame including a seat on the front of said frames, an apron extending downwardly said limits, a toggle interconnecting each pair of adjacent from each seat, a panel at the rear of said frames extend frames, and means engageable by said toggles to move 30 ing :upwardly to the apron of the next taller frame when said other latches out of locking relation to their asso the frames are extended, and a foot rest mounted between the seat and panel, the llower frame being retractable ciated abutments as the yframes are sequentially retracted, the retraction of each -frame conditioning the next taller within and below the taller frame and selectively extensi frame for retraction yby unlocking the latch normally hold ble therefrom, a latch movably mounted to each frame ing said next taller frame. ka5 except the lowest frame, an abutment on each frame ex 5. In a seating structure, a plurality of transverse frames cept the tallest »frame engaging the latch on the next taller of successively decreasing heights, said frames being re frame when the frames are extended so as to prevent tractable in nested relation to the next taller frame and retraction, operating means movably mounted on each frame except the tallest frame and engaging the latch on successively extensible therefrom, a latch movably mounted to each Iframe except the lowest frame, an abut 40 the next taller frame, means hinged to the lowest frame ment on each frame except the tallest frame engaging and movable within limits, means .operatively intercon the latch on the next taller -frame when the frames are necting said hinged means with the said operating means extended so as to prevent retraction, operating means on the lowest frame 'for moving the latch associated with movably mounted on each frame except the tallest frame such operating means out of locking relation to the abut Vand engaging the latch on the next taller frame, means 45 ment on the lowest -frame upon movement of said hinged hinged to the lowest frame and movable within limits, means to one of said limits, and a toggle interconnecting means operatively interconnecting said hinged means each pair of adjacent lframes, each toggle engaging the with the said operating means on the lowest -frame for operating means of its taller associated frame to move moving the latch associated with such operating means the latch of the next taller frame out of locking relation out of locking relation to the abutment `on the lowest frame upon :movement of said hinged means to one of .said limits, and a toggle interconnecting each pair of ad jacent frames, each toggle engaging the operating means to its abutment as the toggle’s lower associated frame is selectively retracted, the retraction of each _frame condi tioning the next taller frame yfor retraction -by unlocking the latch normally holding the said next taller frame. :of its taller asociated Iframe to move the latch of the 9. In a seating structure, a plurality of transverse frames next ta-ller frame out of locking relation to its associated 55 of decreasing heights, each frame including a seat on the :abutment as its lower associated frame is selectively re front of said frames, an apron extending downwardly '.tracted, the retraction of each -frame conditioning the from each seat, a panel at the rear of said frames extend :next taller frame for retraction by unlocking the latch nor ing upwardly to the apron of the next taller frame when mally holding said next taller frame. the yframes are extended, and a foot rest mounted between 6. In a seating structure, a plurality of transverse frames 60 the seat and panel, the lower frame being retractable fof successively decreasing heights, each said frame being within and below the taller frame and selectively exten :retractable in nested relation to the next taller frame and sible therefrom, a latch movably mounted to each frame :selectively extensible therefrom, latching means inter connecting each adjacent pair of frames when the frames except the lowest frame, an abutment on each frame ex cept the tallest frame engaging the latch on the next :are extended so as to prevent retraction, means hinged 65 taller frame when the frames are extended so as to pre to the lowest frame and movable within limits, means operatively interconnecting said hinged means with the said latching means interconnecting the lower pair of adjacent frames yfor unlocking such latching means upon vent retraction, a shoulder on each frame except the low est frame engaging the abutment of the next taller frame when the lower frame is extended so as to enable exten sion of the said next taller frame, an actuating rod slid movement of said hinged means to one of said limits, a 70 ably mounted -for reciprocation on each frame except the toggle interconnecting each adjacent pair of -fra-mes, and other latching means as the frames are retracted, the tallest frame and engaging the latch on the next taller frame, a lever pivoted to the lowest frame, the apron on the lowest frame being hinged and engaging one end of said lever, the actuating rod on the lowest yframe being retraction of >each frame conditioning the next taller frame operatively connected to the other end of said lever, said means associated with each other latching means and lselectively engageable by said toggles for unlocking said 3,088,176 lever moving the latch associated with the 4last said rod out of locking relation to the abutment on the lowest `frame upon movement of said hinged apron, a spring con nected to said lever tending to pivot the lever in a direc tion to move the last said rod to one limit to unlock said 5 latch, and a toggle interconnecting each pair of adjacent frames, each toggle engaging the actuating rod of its associated taller frame to move the latch of the next taller frame out of locking relation as its associated lower frame is selectively retracted. 10 References Cited in the ñle of this patent UNITED STATES PATENTS 2,815,541 Lappin ______ _______ __ Dec. 10, 1957 OTHER REFERENCES Safway Spectator Seating, pp. 4 and 5, catalog No. GS-657 of Safway Steel Products, Inc., Milwaukee 13, Wis.