US3090466A - Slope support compensators for ladders - Google Patents

Description

May 21, 1963 A. J. WRIGHT SLOPE SUPPORT COMPENSATORS FOR LADDERS 2 Sheets-Sheet 1 Filed July 5, 1961 IN VEN TOR.

fl/,giving May 21, 1963 A. J. WRIGHT SLOPE SUPPORT coMPENsAToRs PoR LADDERS 2 Sheets-Sheecl 2 Filed July 5, 1961 INV EN TOR. Wwf; ff fl/fb@ 3,690,465 Patented May 2l, 1963 3 090 466 SLOPE SUPPORT COMPESATORS FOR LADDERS Allen J. Wright, 1229 Latham Square Bldg., Oakland, Calif. Filed July 5, 1961, Ser. No. 121,968 1 Claim. (Cl. 182-202) This invention relates to improvements in means for automatically compensating for variations in the levels of the supporting surfaces for the respective legs of a ladder, and provides a device which can be attached to, or built integral with a ladder or similar two-leg device, and which it is merely necessary to place the ladder in the position to be occupied thereby, and permit the ladder to settle to a firm support, the device having legs which seek the firm support and lock in that position, the weight of a worker on the ladder merely increasing the locking effect, to provide the utmost in safety, with minimum ladder set-up time.

It is known that other devices have been made to supposedly accomplish the purpose, but so far as known, have required a manually operative locking device for securing the legs in an adjusted position. Such devices are completely divergent from applicants invention which requires no external manual locking means, applicants even permitting the Worker on the ladder to shift the upper end of the ladder along its supporting surface, with the device locking the legsfor irm support in the shifted position. However, in one form of the invention neither leg will unlock until the load thereon is removed.

The objects and advantages of the invention are as follows:

First, to provide a device which will automatically compensate for varying levels in the support surface for a ladder or the like.

Second, to provide a device as outlined which will automatically lock the legs of the device in the compensated position when the load of the ladder is applied.

Third, to provide a device as outlined in which the locked legs are released upon freeing of the load thereon.

Fourth, to provide a device as outlined in which a string of interconnected spheroidal elements forms the equalizing connection between the legs and `a wedging friction member forms the locking means and which becomes locked only upon equalization of pressures on the respective legs.

Fifth, to provide a device as outlined which is economically manufactured, easily assembled, and automatic in operation.

In describing the invention reference will be had to the accompanying drawings, in which:

FIG. l is a front elevation of the invention shown partly in section, and as applied to the legs of a ladder, and showing one form of locking means.

FIG. 2 is a side elevation of FIG. l, shown as a section taken on line 2 2 of FIG. 1.

FIG. 3 is a fragmentary sectional elevation illustrating one method of securing the Stringing element.

FIG. 4 illustrating another method of securing the Stringing element and is a fragmentary View partly in section, and drawn to an enlarged scale.

FIG. 5 is an enlarged fragmentary View shown partly in section and illustrating a modification of the clutching or locking means.

FIG. 6 illustrates a modification of the beads in which cylindrical members are provided with spheroidal ends are substituted for the spherical beads, and is a fragmentary view partly in section.

FIG. 7 is an enlarged fragmentary view partly in section illustrating a positive clutching or locking element,

with which neither leg will release until the load is removed, the legs being independently locking.

FIG. 8 is a view similar to FIG. 7 but showing the clutching or locking means in the locked position and which remains locked so long as the load is applied to the leg irrespective of the freeing of the load thereabove.

FIG. 9 shows a modification of the locking means partly in section in which multiple discs are used.

FIG. 10 illustrates another modification, also in part section, in which nonresilient discs are used.

FIG. 1l is a top plan View of the nonresilient type clutching or locking disc.

The invention includes a tubular member which is formed substantially to inverted U-shape as indicated at 12 and including the legs 13 and 14 and cross member 15.

This U-shaped tubular housing may be formed of any suitable material and may be built into the lower end 16 of a ladder 17, or may be provided for mounting thereon as indicated by the brackets 18 and 19, indicated as fixed to the respective legs of the ladder by means of bolts or screws 20.

The support legs 21 and 22 are slidable in the housing legs 13 and 14, and form the terminals of the string of beads or thrust members indicated at 23 with interposed locking means 24, the entire series being interconnected through the medium of a flexible element such as a cord, wire, or cable 25. The ends of the stringer 25 may be secured in any suitable manner, and shown in FIG. l as locked in an inclined bore 26 in the support leg 21, and extending axially through the other support leg 22 and ybeing secured in a counterbore 27 through the medium of babbitt or similar material as illustrated in FIG. 4.

The thrust members are shown as spheres in FIG. 1 and as cylindrical members 28 provided with spherical ends 29, these members or the balls 30 being freely movable though close tting in the tube. The support legs are each provided with a universally conforming foot as indicated at 3l.

The locking member 24 in FIG. l is located intermediate the length of the string of th-rust members and consists of a cylindrical member slidably fitting in the tube and formed of resilient material such as live rubber.

When a load is equalized between the two feet 31, the thrust is equalized on the opposed ends 32 and 33 by the balls 34 and 35, causing the locking member to bulge against the inner periphery of the tube and thus frictionally lock the legs and feet in the specic position. Freeing of the load on one foot will free the clutch 24 and the freed foot will immediately be advanced with retraction of the other until the loads are again equalized at the clutch. Thus a worker at the upper end of a ladder can move the upper end in either direction to a predetermined position with the assurance that the feet will immediately compensate and change to a new balanced support.

As illustrated in FIG. cal, and similarly being 37, one of these resilient leg.

The modification illustrated in FIGS. 7 and 8 consists of a cupped disc 39 which is interposed between two at faced plugs 4t) and 41, all of which are slidable in the tube, the pressures spreading and flattening the cupped disc as indicated in FIG. 8, to a locking position which locks the two support legs independent of each other, and being releasable only through selective freeing of the loads on the legs. Therefore, after the legs are locked while resting on a predetermined supporting surface, it will be necessary to lift the ladder to get the legs to release, after which, the legs would again become 5, the clutch member is spheribulged by the rigid balls 36 and balls 38 being provided for each 3 automatically compensating for variations in support levels for the two legs.

A modification of the positive locking clutches is illustrated in FiG. 9, in which a series of axially spaced cupped discs 42 are formed integral with a central hub and are normally slidable in the housing, and molded as a unit, and with the peripheries spread by rigid rings 43, which are slidable in Vthe housing and cause the several discs to expand and engage simultaneously with increased clutching eiiiciency; with the upper thrust member 44 being bored as indicated at 45 to engage only the peripheral portions of the discs. This type can be compressed to a hat condition producing a greater frictional thrust on the inside walls of the housing.

Another modification vis shown in FIGS. 10 and 11, to show that relatively rigid materials can be used as the clutching or locking means, and consists of a cupped disc 46 of spring 'metal or other suitable relatively rigid material, but which requires radial slotting as indicated at 47 to permit its expansion in the tube.

It will be understood that all of the elements are interconnected and slidable normally in the tube, and that the clutching or locking means consists of any type lwhich can be bulged, spread, or attened, to engage the inner periphery of the tube when pressures are exerted in opposition, the materials being returnable to the normal form when the loads are released.

The types shown in FIGS. l and 11 are provided with the plain disc type thrust members like those shown in FIG. 7.

Thus a ladder is provided which will conform its supporting means to variable surfaces, sloping, level, or stepped as indicated at 48, 49 in FIG. 1.

I claim:

In a slope compensator for ladders and the like, including a tubular housing having depending legs, and a cross member arcuately connecting the upper ends of the legs,

a continuous string of elements normally slidable in said Vhousing and including a exible Stringing element passing through the entire string of elements and having terminal ends,

a support leg for each depending'leg and each slidable in said housing, i

clutch means comprising an upper thrust member cooperative with each end of the string of elements,

a resilient cupped disc member interposed between each upper thrust member and support leg, with the flexible element passing through the upper thrust member and Acupped disc members, with the terminals connected to the `respective legs,

with the legs mutually cooperating in movement of the string within the housing through the weight of one leg as the other leg is urged to retract, and

with the cupped discs lbeing expanded diametrically through opposed pressures between the upper thrust members and the support legs to engage the interior of the housing when the legs are subjected to equal loads,

said cupped disc members each comprising a plurality of axially spaced cupped discs having a central hub, spacing rings slidable in the housing and interposed between the peripheral portions ofthe spaced discs for mutual cooperation, said upper thrust member being counterbored in the undersurface for cooperation solely with the peripheral portion of the contacting disc.

References Cited in the iile of this patent l UNITED STATES PATENTS 383,815 Kilborn May 29, 1888 Y2,017,300 Wiesman Oct. 15, 1935 2,390,168 Piot Dec. 4, 1945 2,548,311 Johnson Apr. 10, 1951 2,665,902 Allen Ian. 12, 1954 2,707,108 Schottler Apr. 26, 1955 2,882,040 Cottrell Apr. 14, 1959 2,947,556 Wenger Aug. 2, 1960 2,969,126 Gardner Jan. 24, 1961 FOREIGN PATENTS 147,367 Australia July 16, 1952 834,075 Great BritainV May 4, 1960

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