US2763420A - Collapsible ladder assemblies - Google Patents

Description

pt. 18, 1956 R. G. HEBERT 2,75%4-2@ COLLAPSIBLE LADDER ASSEMBLIES 2 sheets-sheet 1 Filed D90. 24, 1955 INVENTOR. /cfm @o Gao/m5 HEBER?? Sept.. M, 1956 R. G. HEBERT 2,763,420

COLLAPSIBLE LADDER ASSEMBLIES Filed Dec. 24, 1955 2 Sheets-Sheet 2 rd Rmww. mm3; E @M WH m VLJ/ I@ A l R DW. H njlawlwi M HY CB $131; m m A Mm T .W, wi I J I 1J 4 United States Patent() COLLAPSIBLE LADDER ASSEMBLIES Richard G. Hebert, Jersey City, N. J., assgnor to H H Truck Tank Co., Inc., Jersey City, N. J., a corporation of New Jersey Application December 24, 1953, Serial No. 400,181

7 Claims. (Cl. 228-43) This invention relates to collapsible ladder assemblies and more particularly to a self-winding, reeldtype ladder assembly usable in conjunction with a platform which 1s adapted to be raised to varying heights above the base of said ladder.

It is an object of the invention to provide a platform access ladder which can be raised into rigid operative position automatically upon elevation of :the associated platform itself, and which can wind itself upon a convenient storage reel upon lowering of the platform.

It is a further objectI of the invention to provide a platform access ladder equipped with means to adjust the ladders angle of inclination to the vertical lto compensate for the various heights to which the ladder may be raised.

A further object of the invention is to provide a ladder assembly of the type described which is adapted to be mounted on a vehicle such as a truck having a vertically movable platform to which `access is desired.

A further object is to provide a ladder assembly of the type described characterized by its compactness, ease of assembly and relatively low cost.

Further objects, features and advantages ofthe invention hereof will appear from the detailed descrip-tion given below, taken in connection with the accompanying drawings which form a part of this specification and illustrate by way of example a preferred embodiment of the invention.

In the drawings:

Fig. l is a fragmentary side elevational view of the ladder assembly of the invention showing the same supported in operative position on the rear end of a truck equipped with a vertically movable platform, with the "ice front, side or rear of trucks and mobile trailers where it is desired to provide a working space which may be elevated to various levels above the body of truck or trailer itself. The ladder assembly of the inven-tion is particularly useful in conjunction with such vehicle platforms and for the purpose of illustration has been shown in Fig. l as secured to a vehicle. However it shouldbe understood that it has utility in many other fields and may be used in conjunction with any platform which is to be raised and lowered.

Referring now in more detail to the drawings and particularly to Fig. l, a collapsible ladder assembly 10 is there shown secured in operative position on the rear end of a truck chassis 11. The truck chassis 11 is equipped with a vertically movable platform 12 and a lift mecha nism 13, which latter may be of any desired type such as hydraulic, pneumatic or the like. The ladder assembly 10 comprises a one-way flexible ladder 14 having suitable attachment means 15 `at its upper end to permit said upper end of the ladder to be secured tothe platform 12. Therefore, when said platform is elevated, the ladder 14- can be automatically raised into operative position thereby providing access to the platform as is shown in full line in Fig. l. Due to the provision of rewind means within the ladder assembly, which will be described in detailhereinafter, when the platform 12 is lowered, the ladder 14 will automatically collapse.

Referring now to Figs. 3 and 4, the ladder assembly 10 comprises a housing 16 open at one end as shown at 16 and having up-standing sides 17, 18 to which are bolted plates 19, 20 having cylindrical bosses 21, 22 which latter are internally bored for the reception of a shaft 23. This shaft is fixed relative to the plates 19, 20 and therefore to the housing itself by means of set screws 24, 25. Rotatably mounted upon said shaft is a hollow cylindrical reel 26 having circular end plates 27, 28.

ladder and platform elevated in full line and collapsed in broken line;

Fig. 2 is an end elevational v-iew showing the ladder and platform in elevated position;

Fig. 3 is a side elevational View partially in section of the ladder assembly alone;

Fig. 4 is a cross-sectional view of the ladder assembly taken on the line 4-4 of Fig. 3, showing in broken line additional rungs of the ladder in the position that it would assume when said ladder has been further collapsed from the position shown in Fig. 3;

Fig. 5 is an enlarged partial side elevational view of a side rail of the ladder;

Fig. 6 is an enlarged partial sectional view showing the manner in which the horizontal rungs of the ladder are secured to the side rails thereof;

Fig, 7 is a sectional View taken on line 7-7 of Fig. l, showing the adjustable ladder base and locking 1nechanism therefor; and

Fig. 8 is an enlarged partial sectional view showing the ladder base locking mechanism in the locked position.

The ladder assembly of the invention is designed to provide a convenient means of access to platforms of the type which may be elevated to positions of varying height. Such platforms are commonly provided on either the Within the hollow interior of reel 26 and :inwardly spaced from the end plates thereof are a pair of spaced circular discs 29, 30 which are tack welded at their outer peripheries to the interior of the reel as shown at 31 and 32, and are welded at their inner peripheries to a length of pipe 33 which surrounds the shaft 23 in spaced relation thereto and'extends between said discs. This pipe 33 is provided withinternal bushings 34, 35 at each of its ends which serve as bearing surfaces to permit rotation of the pipe about the shaft. The end plates 27', 28 of the reel are provided with central apertures 36, 37 which are of sufficient size to provide clearance between the plates and the shaft so as to permit free rotation of the reel about said shaft. A coil spring 38, preferably made of ribbon steel, is disposed in the space between end plate 27 and disc 29. As best seen in Fig. 3, this spring 38 is coiled around the shaft 23 with one end secured by a rivet or other suitable means 40 to the interior of reel 26 and the other end hooked into a radial slot 41 formed in a sleeve 42 which is xed relative to shaft 23 by means of a set screw 43. A second coil spring 39 is similarly disposed about the shaft `in the space between end plate 28 and disc 30, with its ends similarly xed to shaft and reel respectively thereby forming a resilient interconnection between said shaft and reel.

The end plates 27 and 28 are secured to the discs 29 and 30 by means of bolts 27 and 28 in order that said side plates may be easily removed thereby permitting convenient access to the springs 38, 39. V-shaped guide members 70 are welded to the interior of reel 26 in position so as to extend between the side plate27 and circular disc 29, thereby providing passageways for the bolts 27 as shown. Similarly V-shaped guide members 71provide passageways for the bolts 28. t

Slidably positioned in the lower part of the housing 16 beneath reel 26 is a ladder base tray 53 which is provided with a ladder base guide means 54 comprising a pair of freely rotatable sprocket wheels 55, 56. Attached to the tray 53 are channel shaped side members 58, 59, which slidably embrace a pair of longitudinally extending raillike members 72, 73 so as to permit telescopic movement therebetween. These raillike members 72, 73 are supported from and in spaced relation to the bottom 57 of the housing by angle members 74, 75. The tray 53 therefore is movable inward and outward relative to the housing 16. A series of spaced apertures 60 is provided in this tray 53, and a lever actuated, locking pawl mechanism 61, designed to co-operate with said apertures, is positioned exteriorly of said housing. This latter mechanism, as shown in Figs. 4 and 8, comprises an operating lever arm 62, which is rotatably journalled in a flange 63 secured to the under side of they housingk bottom 57, and a locking pawl 64, mounted freeon shaft 62 adjacent the flange 63. As seen in Fig. 8 the housing bottom is provided with an aperture 65 and the shaft 62 and pawl 64 carry co-operating lugs 66, 67 respectively. A coil spring 68 is disposed around shaft 62 with one end anchored in flange 63 and its other end bearing against locking pawl lug 67, so as continuously to urge the pawl upwardly through housing bottom aperture 65 and any one of the tray apertures 60 which may at the moment be in line therewith. When the pawl is in the locked position shown in Fig. 8, extending upwardly through aperture 65 and one of the apertures 60, the ladder base tray 53 cannot be moved from right to left, or in other words inwardly of the housing, because of the rigid contact between the pawl, tray and housing bottom. The tray is however free to be moved from left to right, or in other words outwardly of the housing, since the tray 53 will contact the inclined surface 69 of said pawl and cam it downwardly against the laction of spring 68 out of the aperture 60. As soon as the movement of the tray is reversed, however, the pawl will be returned to locking position by spring 68. When it is desired to move the tray inwardly of the housing the locking mechanism may -be released by rotating the shaft 62 clockwise as seen in Fig. 8, whereupon pawl lug 66 will engage the shaft lug 67 thereupon rotating the pawl out of contact with aperture 60.

The ladder 14, itself, comprises rungs 47 and side rails 45, 46 which latter are so constructed as to possess only one-way flexibility, or in other words, said side rails are designed so that they will maintain rod-like rigidity when (looking at Fig. l) force is applied thereto in the direction of arrow A, and yet are capable of exing around sprocket wheels 55, 56 and storage reel 26. The precise design of these side rails may take many forms, one being the one-way flexible sprocket chains disclosed herein. Referring now to Figs. and 6, these sprocket chains are ycomprised of a plurality of links 48 pivotally interconnected by pins 49. Each link is provided on one side with lugs 50 and 51 which abut as at 52 when the ladder is elevated as shown in full line in Fig. l and thereby restrict the pivotal movement of said links in one direction about the pins 49. However since no such lugs are provided on the other side of the links 48, unrestricted pivotal movement in the opposite direction is permitted thereby providing the chain with one-way flexibility. As seen in Fig. 6. the horizontal rungs 47, which may be formed of hollow pieces of pipe, are secured to the sprocket chains by the simple expedient of forming certain of the pivot pins 49 with extensions 49 over which the hollow rungs 47 may be telescoped and suitably secured thereto.

As mentioned above, the upper end of ladder 14 is provided with attachment means 15 which permit said upper end to be connected to the platform 12. The lower end of the ladder is riveted or otherwise suitably secured as at 44 to the reel 26, and between said ends the sprocket chain risers 45 and 46 of the ladder pass around the sprocket wheels 55 and 56 of the ladder base guide means.

The mode of operation of the device will now be described:

When the platform 12 is at its lowermost position as shown in broken line in Fig. l, the ladder 14 is collapsed and coiled about storage reel 26 as shown in broken line in Fig. 4. When desired the platform may be elevated by lift mechanism 13 to any desired height within the range of the particular mechanism. This range varies of course with the installation but when platforms of this type are provided on trucks or similar vehicles, said range usually permits elevation of the platform to a height in the order of 15 feet above the chassis. As the platform 12 rises to the full line position shown in Fig. l, the ladder 14 is automatically raised into rigid operating position due to the connection of its upper end 15 to the platform. When in this operative position the ladder provides convenient access to the platform, since a worker may climb said ladder and the same will not yield or flex due to his weight. This rigidity is of course due to the one-way llexible sprocket chains 45, 46 having abutting lugs 50, 51 described abo-ve. During the simultaneous elevation of the platform and ladder, the Vreel 26 will be rotated on shaft 23` thereby permitting uncoiling of the ladder from the reel and at the same time storing energy in the coil springs 38, 39, much in the same way that energy is stored in a watch spring upon winding. When the platform is lowered by releasing lift mechanism 13, the ladder will collapse and be automatically rewound about reel 26 due to the rotation of said reel caused by the release of the stored energy in springs 38, 39. As shown, the sprocket chain side rails of the ladder are continuously guided by the sprocket wheels 55, 56 of the ladder base guide means. These sprocket wheels are carried by the adjustable ladder base tray 53 and their position relative to the housing determines the ladders angle of inclination to the vertical. This adjustable feature is necessary to compensate for the various heights to which the platform can be raised. For example, assuming that the plat-form 12 is raised to a higher elevation than shown in full line in Fig. l, if the ladder base tray and sprocket wheels were to be left in the same positon, the ladder itself would approach more nearly to an absolute vertical position. Since, for ease of climb, a suitable inclination to the vertical is always desirable, this would be a disadvantage to the utility of such a ladder. However, because the ladder base tray herein is slidable relative to the housing, it may be moved outwardly relative to said housing for each additional elevation of the platform thereby maintaining the desired ladder angle of inclination to the vertical. When it is desired to move said ladder base tray and its sprocket guide wheels outwardly of said housing, to compensate for a higher elevation of the platform, the tray may be manually pulled outwardly of the housing. As described above in connection with Fig. 8, when the tray is pulled in that direction it will cam the locking pawl 64 downwardly out of engagement with the particular apertures 60 with which it is at the moment engaged. As outward movement of the tray is continued the pawl 64 under the action of spring 68 will automatically `be urged upward into each of the apertures 60 as they pass over housing bottom aperture 65. When the appropriate setting of the sprocket wheels relative to the housing has been reached soV as to provide for proper inclination of the ladder, outward movement of the tray is discontinued and the pawl 64 will enter that aperture 60 which is then in alignment with aperture 65. As has been described above, in this position the tray is locked against inward movement relative to the housing by virtue of the locking action of the pawl, and therefore the ladder base guide means willremain stationary when subjected to the weight of the worker climbing the ladder 14. When it is desired to mo-ve the ladder base tray and guide means inwardly towards the housing, the same can easily be accomplished by means of operating lever arm 62. This lever arm performs in the same manner whether the ladder be in the elevated or collapsed position and, when rotated clockwise as shown in Fig. 8 and described above, will rotate the locking pawl downwardly and out of contact with the tray 53, thereby permitting said tray to be pulled inwardly of the housing.

Although certain particular embodiments of the invention are herein disclosed for purposes of explanation, various further modifications thereof, after study of this specification, will be apparent to those skilled in the art to which the invention pertains. Reference should accordingly be had to the appended claims in determining the scope of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. A self-Winding, reel-type ladder assembly usable in conjunction with a platform which is adapted to be elevated, comprising a housing having a shaft xedly mounted therein, a reel rotatably mounted on said shaft, resilient means interconnecting said reel and shaft, adjustable ladder base guide means slidable relative to said housing and a one-way exible ladder having one of its ends secured to said reel and extending around said guide means and having its other end adapted to be secured to said platform whereby when said platform is raised the ladder will be unwound from the reel and positioned so as to permit access to said platform and when said platform is lowered the ladder will automatically be rewound upon said reel.

2. A self-winding, reel-type ladder usable in conjunction with a platform which is adapted to be raised and lowered to varying heights, comprising a housing having a shaft ixedly mounted therein, a reel rotatably mounted on said shaft, spring means interconnecting said reel and shaft, a one-way flexible ladder having one of its ends secured to said reel and having its other end adapted to be secured to said platform whereby when said platform is raised the ladder will be unwound from the reel and positioned so as to permit access to said platform and when said platform is lowered the ladder will automatically be rewound upon said reel, and ladder base guide means cooperating with said ladder between its ends and slidable relative to said housing whereby the Vertical inclination of the ladder may be adjusted to compensate for various elevations to which the platform is raised.

3. A self-winding, reel-type ladder assembly usable in conjunction with a platform which is adapted to be raised and lowered to varying heights, comprising a housing having a reel rotatably mounted therein, resilient rewind means for said reel, ladder base guide means mov able relative to said housing and a one-way exible ladder having one of its ends secured to said reel and extending through said guide means and having its other end adapted to be secured to said platform whereby when said platform is raised the ladder will be unwound from the reel and positioned so as to permit access to said platform and when said platform is lowered the ladder will automatically be rewound upon said reel.

4. A self-winding, reel-type ladder assembly usable in conjunction with a platform which is adapted to be raised and lowered to varying heights, comprising a rotatably mounted reel, adjustable ladder base guide means movable relative to said reel and a one-way flexible ladder having one of its ends secured to said reel and extending through said guide means and having its other end adapted to be secured to said platform whereby when said platform is raised the ladder will be unwound from the reel and positioned so as to permit access to said platform and reel rewind means whereby when said platform is lowered the ladder will automatically be rewound upon said reel.

5. A collapsible ladder assembly comprising a rotatably mo-unted ladder storage means, a one-way flexible ladder having one of its ends secured to said storage means and provided at its other end with means .adapted to be secured to a vertically movable platform, automatic rewind means connected to said storage means and ladder base guide means co-operating with said ladder between its ends and laterally movable relative to said storage means.

6. A collapsible ladder assembly usable in conjunction with a platform which is adapted to be raised and lowered to varying heights, comprising a rotatably mounted ladder storage means, a one-way flexible ladder having one of its ends secured to said storage means and having its other end adapted to be secured to said platform whereby when said platform is raised the ladder will be unwound from said storage means and positioned so as to permit access to said platform, rewind means for said storage means whereby when said platform is low ered the ladder will automatically be rewound upon said reel, and ladder base guide means co-operating with said ladder between its ends and laterally movable relative to said storage means whereby the vertical. inclination of the ladder may be adjusted to compensate for various elevations to which the platform is raised.

7. A exible ladder assembly comprising, in combina tion, an elevatable member having a normal lowered position, a drum disposed below said member and being mounted for rotation about a fixed axis, a flexible ladder wound on said drum and extending to and being connected :at its upper end to an edge of said member, whereby the ladder is unwound from said drum responsively to elevation of the member, spring means operatively connected to and biasing said drum against rotation in ladder-unwinding direction, whereby the ladder is rewound on the drum responsively to lowering of said member, means for causing the portion of the ladder between drum and member to extend rst outwardly from the drum and thence upwardly to said member, and means for inclining the upwardly extending portion of the ladder toward said member, wherein said ladder inclining means is effective to incline the ladder to a selected one of a plurality of predetermined inclinations.

References Cited in the le of this patent UNITED STATES PATENTS 293,215 Baar et al. Feb. 12, 1884 456,382 McPartland July 21, 1891 1,003,967 Magliocca Sept. 19, 1911

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