Abstract:
A mobile storage system universal anti-tipping system includes at least one auxiliary track and at least one anti-tip structure attached to the mobile shelving carriage and retained by the track. The auxiliary track defines a gap which cooperates with an extended portion of the anti-tip structure to prevent the carriage and supported mobile storage unit from tipping over.

Description:
BACKGROUND OF THE INVENTION 
     The present invention pertains to a mobile storage system including an anti-tip system for preventing tipping of the individual storage units. Generally, mobile storage systems fill the floor with movable side-by-side shelving units so that only a single aisle is provided in the entire storage area. An example of such a system is illustrated in U.S. Pat. No. 4,597,615 to Steger, and entitled STORAGE SYSTEM. Access to a particular unit is enabled by moving certain of the mobile shelving units to create an aisle adjacent the unit. 
     However, without the provision of an anti-tip arrangement, these mobile systems are subject to certain governmental safety restrictions. More specifically, OSHA regulations prohibit mobile storage units without an anti-tipping arrangement from exceeding a height-to-width ratio of 4 to 1. Accordingly, a typical two foot wide storage unit is limited to a height of eight feet. Furthermore, the California Seismic Safety Authority has ruled that all mobile storage systems installed in California must include anti-tip systems due to the additional hazards caused by earthquakes. 
     A common type of anti-tip system involves the use of upper bracing systems which fixedly mount to the ceiling, an adjacent wall, or on columns extending up from the floor. These bracing systems are coupled with the upper portions of the storage units to prohibit their tipping. One example of such a system is disclosed in copending application 07/129,683 filed Dec. 7, 1987, and entitled MOBILE SHELVING ANTI-TIP MECHANISM. This type of arrangement, however, is complex, expensive to fabricate and install, and produces an unsightly appearance. Moreover, if used in California, one must additionally verify that the ceiling, wall, or columns are sufficiently strong to resist the extra loads in the event of an earthquake. 
     Another type of anti-tip system is that manufactured and sold by Kardex, Inc., which includes specially designed carriages and carriage tracks. More particularly, the carriage tracks have raised outer edges which define narrow grooves with the floor. The carriages have cooperating L-shaped flanges which are received within the defined groove to prevent the shelving units from tipping over. Although, this arrangement eliminates many of the above mentioned shortcomings, such a system still includes several problems. More particularly, large stresses are generated within the track to offset the great moment forces invariably produced by the tipping. Accordingly, the carriage tracks must be extremely strong and rigid to sufficiently offset the risk of structural failure. Additionally, these anti-tip systems cannot be readily retrofitted to existing mobile shelving systems. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a unique anti-tip system includes a floor-mounted auxiliary track and a cooperating structure attached to the movable carriage and retained by the auxiliary track. The present system can be retrofitted on nearly any mobile storage system. By employing an auxiliary track, additional stress loads on the carriage tracks are avoided. Since the system is floor mounted, the additional expenses and difficulties frequently involved in California installations are eliminated. 
     These and other objects, advantages, and features of the present invention will be more fully understood and appreciated by reference to the written specification and appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a first mobile storage system supporting a mobile storage unit and including an anti-tip system of the present invention; 
     FIG. 2 is a second mobile storage system supporting a mobile storage unit and including the anti-tip system; 
     FIG. 3 is a fragmentary perspective view of the anti-tip system in use with the first mobile storage system; 
     FIG. 4 is a cross-sectional view taken along lines IV--IV in FIG. 3; 
     FIG. 5 is an end elevational view of an anti-tip track of the anti-tip system; 
     FIG. 6 is a fragmentary top plan view of the anti-tip track; 
     FIG. 7 is an exploded perspective view of the two main components of the anti-tip system in use with the first mobile storage system; 
     FIG. 8 is a fragmentary perspective view of the anti-tip system in use with the second mobile storage system; 
     FIG. 9 is a cross-sectional view taken along line IX--IX in FIG. 8; and 
     FIG. 10 is a fragmentary perspective view of the main components of the anti-tip system in use with the second mobile storage system. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Anti-tip system 10 basically includes an auxiliary or retainer track 12 and a cooperating retainer or anti-tipping flange 14. Anti-tip system 10 can be used in conjunction with virtually any mobile storage system. For illustrative purposes, system 10 is shown in use on two different mobile storage systems 16, 18 (FIGS. 1 and 2). In general, storage units of storage systems 16 will tend to tip in directions indicated by arrows 17, and those of storage systems 18 will tend to tip in directions indicated by arrows 19. 
     A typical mobile storage system 16 (FIG. 1), includes a pair of carriage tracks 20 and a carriage 22 rollingly supported thereon. Carriage 22, in turn, functions to movably support a mobile storage unit 24 such as shelves for movement along tracks 20. Carriage 22 is generally a rectangular framework comprised of a pair of relatively short longitudinal members 26 overlying the carriage tracks 20, and a pair of interconnecting, relatively long transverse members 28. Longitudinal members 26 are each provided with a plurality of downwardly projecting rollers 30 rollingly engaging carriage tracks 20. Members 26, 28 further include upper supporting surfaces 31, 33 upon which the mobile storage unit 24 is placed. These units 24 are then typically secured by bolting or the like to a member of the carriage 22, such as upstanding corner supports 35. Although only one carriage is illustrated, any number of carriages could be supported on the carriage tracks. Likewise, additional carriage tracks could also be used if the storage units were long. 
     Auxiliary track 12 is essentially an elongated Z-shaped plate member having a retaining or anti-tipping segment 32, base segment 34, and an upstanding medial segment 36 (FIGS. 4-7). In use, base segment 34 lies flush against the floor 38 and is secured thereto with bolts 44 or the like. To facilitate this mounting, base segment 34 is provided with a series of holes 42 through which bolts 44 may be passed. Of course, other securing arrangements could be used. Medial segment 36 and retaining segment 32 then define with floor 38 a narrow, elongated gap 40. In addition, retaining segment 32 is preferably at a slight inclination to the horizontal, at an angle A of approximately three degrees. This arrangement enables the track to better resist the tipping forces (as discussed below) and prevent the flange from becoming inclined upwardly after repeated use. 
     Cooperating with auxiliary track 12 is an L-shaped retainer flange 14 including a vertical mounting portion 46 and a horizontal finger portion 48 extending orthogonally therefrom (FIGS. 3, 4, and 7). In the preferred embodiment, mounting portion 46 includes a pair of holes 50 to receive therethrough bolts 52 for mounting flange 14 to one of the transverse members 28. Of course other mounting arrangements could be used. Finger 48 extends outwardly and laterally from mounting portion 46, such that a free end 54 is defined. Free end 54 is positioned for receipt within gap 40. In normal operation, free end 54 is spaced between retaining segment 32 of auxiliary track 12 and floor 38 so that it makes no engagement therewith to inhibit the rolling of the carriage 22. However, should storage unit 24 begin to tip, free end 54 would quickly engage either of segment 32 of auxiliary track 12 or floor 38, depending on the particular spacing provided between the elements. Moreover, the inclination of segment 32 of auxiliary track 12 will also tend to prevent slippage of flange 14 from gap 40 due to a twisting motion of the storage unit 24. 
     Auxiliary track 12 is positioned between carriage tracks 20 so that it underlies carriage 22 (FIGS. 1 and 3). In the preferred arrangement, auxiliary track 12 is mounted adjacent one of the carriage tracks 20 such that gap 40 opens outwardly therefrom and toward the opposing carriage track 20. Nevertheless, auxiliary track 12 could be placed anywhere beneath carriage 22 and face in either direction. When used with smaller mobile storage units, one auxiliary track 12 and cooperating retainer flange 14 will generally be sufficient to eliminate the tipping hazard. However, with longer mobile storage units a pair of auxiliary tracks 12 should be used with one positioned adjacent each of the outside carriage tracks to prevent the unit from twisting and falling (FIG. 1). 
     Additionally, anti-tipping system 10 may also be used in conjunction with the second mobile storage systems 18 (FIGS. 2 and 8-10). In these arrangements, retainer flange 14 is preferably mounted to the longitudinal members 26a of carriage 22a. In this embodiment, longitudinal members 26a are relatively long and transverse members 28a are relatively short. This difference, in turn, affects the potential tipping directions by reorienting them ninety degrees relative to the carriage tracks. In this arrangement auxiliary track 12 faces toward the adjacent carriage track 20 to receive the entire longitudinal outer edge 58 of finger 48, rather than just the free end 54 as discussed above. A spacer 56 may be used to mount retainer flange 14 to carriage member 26a, if necessary to adequately space flange 14 beyond the adjacent carriage track 20. Additionally, only one auxiliary track will be needed even when used with long storage units. As can be seen in FIG. 2 any twisting motion can be prevented through the use of a pair of flanges 14 attached to opposite ends of carriage 22a. Of course two tracks could be used if desired. The downward inclination of segment 32 also, in this embodiment, provides a secure and stable flat-to-flat contact with anti-tip flange 14. This arrangement reduces large point stresses in the components and increases the frictional resistance between the flange 14 and auxiliary track 12 to further alleviate the chance of slippage. Otherwise, as can be readily appreciated, system 10 includes the same elements and operates in the same manner as discussed above. 
     The above description is that of a preferred embodiment of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as set forth in the appended claims, which are to be interpreted in accordance with the principles of patent law, including the doctrine of equivalents.