US3102606A

US3102606A - Adjustable legs for ladders

Info

Publication number: US3102606A
Application number: US99657A
Authority: US
Inventors: Hopfeld Henry
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-02-21
Filing date: 1961-02-21
Publication date: 1963-09-03
Anticipated expiration: 1980-09-03

Description

Sept. 3, 1963 v v H. HOPFELD 3,102,605

ADJUSTABLE LEGS FOR LADDERS Filed Feb. 21; 1961 5 Sheets-Sheet -l INVENTOR. HEN/FY HOPFELD ATTORNEY Sept. 3, 1963 H. HOPFELD ADJUSTABLE LEGS FOR LADDERS Filed Feb. 21, 1961 5 Sheets-Sheet 2 w Y 4 w H E llll D M W? l l I I l l 1 .I l 0 H l I ll Ill 1 I H m 3 T Y A P a m H Sept. 3, 1963 H. HOPFELD ADJUSTABLE LEGS FOR LADDERS 5 Sheets-Sheet 3 Filed Feb. 21, 1961 INVENTOR. HENRY HOPFELD ATTORNEY H. HOPFELD 3,102,606

ADJUSTABLE LEGS FOR LADDERS Filed Feb. 21, 1961 5 Sheets-Sheet 4 IIQVVENTOR. HENRY HOPFELD ATTORNEY Sept. 3, 1963 H. HOPFELD ADJUSTABLE LEGS FOR LADDERS 5 Sheets-Sheet 5 Filed Feb. 21 1961 INVENTOR. HENRY HOPFELD %Mz ATTORNEY able leg thereon.

United States Patent 0 3,102,606 ADJUSTABLE LEGS non LADDERS Henry Hopfeld, Him Co., 732 A St., San Rafael, Calif.

Filed Feb. 21, 1961, Ser. No. 99,657 2 Claims. (Cl. 182-402) nector to bulge into locking engagement with said lock and thereby hold the legs in the adjusted position and at the adjusted levels at which the feet of the legs rest upon the respective supporting surfaces for the ladder.

A benefit of this invention is that it eliminates the necessity and the danger attendant to the use of a separate manipulable locking mechanism for holding the legs in certain adjusted position only when the locking mechanism is locked and also to eliminate the necessity for any manual operation for releasing the locking engagement whenever the weight is removed from the ladder; in other words, the benefit of the herein invention is that the respective legs can be adjusted to the necessary heights to conform to uneven level of the supporting surface and maintain the ladder in generally perpendicular position and then, without manipulating any locking mechanism by simply placing weight on the ladder, the legs are automatically locked in the adjusted position irrespective whether the weight is on the lowest or any other rung of the ladder; and whenever the weight is released from the ladder, then the legs can be readjusted gain.

Particularly this benefit is accomplished by connecting the telescoping legs by a resiliently flexible connector element which extends through a single tubular guide from one leg to the other, utilizing this resiliently flexible connector element for maintaining a rigid, non-compressible, spacer device between the legs which is shifted as a body as the legs are telescoped to relatively different levels, and forming the spacer device with engagement members adapted to engage a locking member along said guide in a suitable position so that when weight is placed upon the ladder, it causes the pressure exerted upon the telescoping legs to urge the flexible connector to bulge in the direction of said locking member and thereby push the engagement member on the spacer device into locking engagement with said locking member.

i I am aware that some changes may be made in the general arrangements and combinations of the several devices and parts, as well as in the details of the construction thereof without departing from the scope of the present invention as set forth in the following specification, and as defined in the following claims; hence I do not limit my invention to the exact arrangements and combinations of the said device and parts as described in the said specification, nor do I confine myself to the exact details of the construction of the said parts as illustrated in the accompanying drawings.

With the foregoing and other objects in view, which Will be made manifest in the following detailed description, reference is had to the accompanying drawings for the illustrative embodiment of the invention, wherein: FIG. 1 is a perspective view of a step-ladder, one side of which is provided with the adjustable leg of the invention herein.

FIG. 2 is a front view of the ladder with the adjust- FIG. 3 is a more or less conventional means for hold-. ing the step ladder in spread attitude, the section being. taken on lines 3-3 of FIG. 2.

FIG. 4 is an enlarged sectional view of the adjustable legs and the locking device on the lower end of a ladder.

FIG. 5 is a fragmental partly sectional view of the locking means of the ladder in unlocked position permitting relative adjustment of the telescopinglegs.

FIG. 6 is a fragmental sectional view of an embodiment of the non-compressible filler spacer between the legs in the form of washers of alternating larger and smaller diameters. I

FIG. 7 is a front view of the washers shown in FIG. 6 with a smaller conical'washer being exposed to view.

FIG. 8 is a top plan view of one of the feet on one of the legs viewing 8-8 of FIG. 4.

FIG. 9 is a fragmental sectional view of the lower end of one of the legs and the foot adjustably secured thereon.

FIG. 10' is a sectional detail View showing the attachment of the adjustableleg device to a rail of a ladder, partly in section, wherein the rail has a dent in it for the contour of the tubular connection between the legs.

FIG..11 is a partly sectional and fragmental view of the securing of the adjustable leg device to a conventional rail.

FIG. 12 is a sectional view on an enlarged scale of the adjustable legs on a ladder as adjusted to dilferent levels.

FIG. 13 is a fragmental view of the ladder withthe legs partly in section in a form where the alternate spaci g washers extend from foot to foot of the respective telescoping legs.

FIG. 14 is a fragmental view of the ladder with the leg structure partly in section, and locks in each corner of the guiding tubular structure.

FIG. 15 is a partly sectional view of the leg device with a single central lock.

FIG. 16 is a partly sectional veiw of the adjustable leg device showing solid non-compressible rubber filler spacer for each telescoping leg.

.FIG. 17 is a fragmental sectional view showing the tilting of a foot on the leg to conform to a slanting level surface. j

While the invention herein is illustrated in FIG. 1 in connection with a step-ladder, it is to be understood that the telescoping adjustable legs herein described can be used on straight ladders or extension ladders or Whatever ladders may be used in places where the problem of uneven surface is encountered. In the case of step-ladders of the type shown in FIG. 1, if the level under the other legs of the step-ladder is uneven, then sometimes the step-ladderis held in a position in the form of a tripod. Wherever there is a frequency of uneven surface under both ends of a step-ladder, then both sides of the step-ladder can be provided with the adjustable legs. The invention prirnarily resides in the adjustable legs provided for the lower ends of ladders of any type.

'Iliebasic elements of the invention include a generally U-shaped tubular guide 1 the opposite legs 2 of which are suitably secured on the lower ends of the rails 3 of a ladder. In each of the fixed legs 2 of the U- shaped guide 1 is telescopingly held a telescopic leg 4. On the lower end of each telescopic leg 4 is provided a foot structure 6.

The telescopic legs 4 arewheld in the tubular guide 1 by means of a resiliently flexible holding element, in the adjustable present illustration a spring wire 7 one end of which is generally in the direction of the arrow 7 ers.

1 and has its other end secured in the other foot "strucand the reaction force causes the spring wire 7 to bridge.

in the curved portion of the guide 1. At a certain point of the u-s haped guide 1, for instance in the form'shown in FIG. 4 in the left corner curved portion, there is provided a keeper locking element 9 capable of being engaged by locking elements on the adjacent portion of the non-compressible filler 8 when it budges with the spring wire 7 outwardly at the turn or corner of the U- shaped guide -1 and thus while the load presses upon the .U-shaped guide 1, the respective telescopic legs 4 are locked in the adjusted position and are restrained from inward telescoping.

In the form shown in FIG. 4, the compressible filler element is made of two types of fillers. There is a locking member 8 adjacent to the area which would move .past the locking element 9' during the adjustments of the respective legs 4. g This locking member 8 is constructed of a series of alternating washers 11 of smaller diameter and washers 12 of larger diameter, as particularly shown in detail in FIG. 6. All the washers have a hole 13 therethrough which loosely receives the connector wire 7. The keeper locking element 9 in this illustration includes a keeper body 14 held by a suitable set screw 16 in a socket 17'of a boss 18 projecting outwardly from the left corner of the U-shaped guide 1 as viewed on FIG. 4; The inner face of the keeper body 14 has a plurality of keeper recesses 19 generally to form teeth 21 so that the teeth 21 between the recesses 19 project into the space between adjacent larger washers 12, as particularly shown in FIG. 4, and thereby lock this entire non-compressible body against axial movement in V the U-shaped guide l, as shown in FIG. 4.

d In order to facilitate'disengagement of the washers '11' and 12 from the'recesses'19 or teeth 21 for adjustment when there is no load on the ladder, there is pro;- vided' a ball 22 which projects fnorn the reduced end 23 of a socket'24 in the projecting boss 18 and is yieldably held in such projecting position by a coil spring 26 and by'an adjusting screw 27. By adjusting the screw 27 the-tension of the spring pressed ball 22 can be adjusted so that as force is exerted for relative adjustment, it has to overcome the pressure on the ball'22 in order -to pass the same. When the periphery of the larger Washer 12 passes catch 22, it is pressed inwardly of the adjacent corner curvature of the U-shaped guide 1 and out of engagement from the keeper recesses 19 and teeth 21 in the manner shown in FIG. 5. faces of the smaller washers or disks 11 are frustoconical so as to render the series of Washers flexible to conform to the shape of the guide 1.

The alternate washers may be extended throughout the entire length of the connecting wire 7 as illustrated in the modified form shown in FIG. 13. Under present circumstances this would be a comparatively expensive construction and therefore a second filler spacer, also flexible and non-cornpressible, is provided in the form of a tightly coiled wire 31to fill the space from the bottom of each telescoping leg 4 to the series of wash- The-series of washers is only of sufiicient length to permit for the extreme adjustment in either direction relatively to the locking device 9. In other words, the series of washers extends in the guide .1 from each end of. the keeper locking member 9 to a distance at least equal to, the distance of maximum inward telescoping of the respective telescopic legs 4.

The opposite As shown in FIGS. 1 and 2, the U-shaped guide 1 is secured to the ladder by suitable clamps '32, and also by a special rung 33 on the ladder, each end of which latter is provided with a clamp head 34 with a pocket or recess 36 to fit over the guide legs 2. Securing flanges 37 on the clamp head 34 are adaptable to be secured to the adjacent respective faces of the rails 3 of the ladder.

As shown in FIG. 10, in certain constructions, particularly Where the ladder is furnished with the adjustable legs thereon, the rail 3 is provided with a longitudinal recess or groove 39 into which fits a portion of the outer periphery of the guide leg 2. In the event that the adjustable legs are furnished as attachments for a standard ladder, then they may be secured onto the inner surface of a rail 3, as shown in FIG. 11, with. the only change involved being a conformably larger socket 36 in the head 34- of the lowest rung 33 oi the ladder.

The anchoring of the respective ends of e connector wire 7 is of importance for two benefits, namely: for secureness in order to fix the length of the connector wire in the guide yet exert bulging force on the same, and also to permit the tilting of the respective feet for more flexibility 'ot'adjustment to the contour of the ground. The particular structure :of this anchor is illustrated in FIGS. 4, 8 and 9. In the lower end of each telescopic leg 4 is fixedly held a plug 41; a flange 42 of which abuts against the extreme end of the respective telescopic leg 4. The outer or lower end of the plug 41 under the flange 4 2 is formed with a tapered body 43, tapering to a reduced neck 44, and then enlarged into a globe or ball 46, which latter is .adjustably held in a socket 47 of the foot plate 48. A central hole 49 extends axially through the plug 41 and the neck 44 and the ball 47. At about the center of the ball 47 is a radial or transverse hole 51 generally at right angles to the axial hole 49 and a set screw 52 screwed into the horizontal hole 51 engages the spring wire 7 inserted through said hole 49. As the horizontal hole 51 is formed, .its end is extended so as to forrn an inner socket '53 opposite the hole 51 so that the screw 52 can bend and press the end of the win-e7 into the socket 53 and thereby positively prevent disengagement of the connector wire 7 from the ball 46.

The ball 46 is held in the'socket 47 by means of a specially formed split washer 54. This washer 54 is generally circular and has a central hole 56 which fits over the upper portion or the ball 46. The socket 47 extends somewhat above the horizontal center plane of the ball 4-6, and the washer 54 therefore fits above the horizontal center plane of the ball 46; The'washer 54 is divided by a radial slit '57 extended from its periphery to said central hole 56 on one side only, and the washer is made of sufliciently flexible material so that it can be twisted apart and swung over the upper portion of the ball 46 and then flattened on the hat top face 53 of the boss 59' on the top of the foot plate 48. Then the washer 54 is firmly secured in place by suitable screws '61, as shown in FIGS. 8 and 9. This forms a firm anchoring for the ends of the connector wire 7 and it provides a firm support for each foot structure 6, which is of suificient flexibility to allow it to be tilted as needed for further conformance to the gnound as illustrated in FIG. 17. p

In the modified form, as shown in FIG. 13, as heretofore mentioned, the washers 11 and 12 are extended over the full length of the wire 7.

In the form in FIG. 14 the same structure in general is utilized as in FIG. 4, heretofore described, except that in certain installations for further security more than one lock is required. In such instance, a suitable boss 62 is provided at each curved turn of the U-shaped guide and each, boss 62 contains the same type of keeper locking device, as shown in the lefthand corner of FIG. 4, which operates in the manner heretofore described, except that the wire 7 is bulged toward both corners under endwise pressure. For this purpose the configuration of the U-shaped guide is such that its middle portion 63 is flattened so that the curvatures are pronounced at both corners to aid in bulging in each corner.

In the modified form shown in FIG. 15, the boss 64- is shown in the center of the arcuate half-circle top 66 of the guide which is shaped in this manner so that the bulging occurs at the center. The boss 64 contains the keeper locking device already described and as shown in the lefthand corner of FIG. 4.

FIG. 16 shows a modified form of the device operating in the same manner as that shown in FIG. 4, except that there is substituted for the tightly Wound or coiled wire filler of the form of FIG. 4 a flexible but noncompressible solid plastic or rubber composition filler body 67 of such nature as to be smoothly slidable in the guide 1 in opposite directions with the respective adjustmerits.

In operation the ladder is placed on the ground, whatever configuration it may be, and then one leg of the ladder is pushed down with sufiicient force to allow the adjacent telescopic leg 4 to be pushed into the U-shaped guide, which then will push the filler inbetween and thereby push out the other telescopic leg 4, for instance, in the relative height position shown in FIG. 1, or in FIG. 12. Then as both feet 6 of the telescopic legs 4 rest on the respective surfaces, then load is placed upon the ladder either by stepping on it or by just manually hanging on it and that is suificient to bulge the wire 7 toward the respect-ive keeper locking device 9 in the respective curved portion or corner of the guide 1 so that the locking member 8 in this illustration formed by the washers 11 and 12 is pushed into engagement with the keeper locking device 9. Such load or weight will positively lock both telescopic legs 4 in the adjusted position as long as the weight or load is on the ladder.

A flexible noncompressible filler substantially in the shape of the toothed structure as formed by the washers 11 and 12 may be utilized, so that alternate recesses and projections interlock with the recesses and projections of the keeper locking device, when the connector spring 7 bulges or expands into the curved portion or corner of the guide 1. As long as the load keeps the connector wires 7 bulged, the interlocking elements at the lock wili prevent relative movement of the filler spacer which filler spacers by hearing against the bottoms of the telescopic legs 4, prevent relative movement of the telescopic legs 4. After the load is removed, the spring Wire 7 returns to its initial position, aided by the spring pressed ball 22, so ,as to allow repeated adjustment of the telescopic legs 4 in opposite directions as needed.

I claim:

1. An adjustable leg device for a ladder comprising a tubular guide adapted to be fixedly secured to the lower end of a ladder, generally parallel leg portions on said guide, a telescopic leg in each of said leg portions, a foot on the outer end of each telescopic leg, a resiliently flexible line extended through said guide, means to connect the ends of said line (to the respective telescopic legs for movement with said telescopic legs in opposite directions according to the adjustment of said telescopic legs relatively to said guide, a curved portion on said guide beyond the limit of telescoping of said telescopic legs, a locking keeper device fixed in said curved portion, locking elements on said line adjacent said locking keeper device normally held by said line out of engagement with said locking keeper device, said line bulging in said curved portion when both telescopic legs are pressed inwardly of said guide simultaneously thereby to interlock said locking elements with said locking keeper device, and spacer means connected to said locking elements to restrain the telescoping of said telescopic legs when said locking elements are in interlocking position, said locking elements being strung on said line and having holes therethrough fitting on said line so that the bulging of said line pushes said locking elements outwardly against said keeper device and the contracting of said line pull-s said locking elements away drom said keeper device, spaced projections formed by said locking elements projecting toward said keeper device; said keeper device including spaced recesses intcrengageable with said spaced projections; and said locking elements being adapted to follow the contour of said guide when moved therein.

2. An adjustable leg device 'for a ladder comprising a tubular guide adapted to be fixedly secured to the lower end of a ladder, generally parallel leg portions on said guide, a telescopic leg in each of said leg portions, a foot on the outer end of each telescopic log, a resiliently flexible line extended through said guide, means to connect the ends of said line to the respective telescopic legs for movement with said telescopic legs in opposite directions according to the adjustment of said telescopic legs relatively to said guide, a curved portion on said guide beyond the limit of telescoping of said telescopic legs, a locking keeper device fixed in said curved portion, locking elements on said line adjacent said locking keeper device normally held by said line out of engagement with said locking keeper device, said line bulging in said curved portion when both telescopic legs are pressed inwardly of said guide simultaneously thereby to interlock said locking elements with said locking keeper device, and spacer means connected to said locking elements to restrain the telescoping of said telescopic legs when said locking elements are in interlocking position, said locking elements comprising a series of rigid disks, each disk having a hole theret-hrough, said line extending through said holes, said disks being of difiFerent diameters, the smaller and larger diameter disks alternating in said series so as to form spaced projections toward said locking keeper device; said keeper device including spaced recesses interengageable with said spaced projections, the opposite faces of the smaller disks being shaped so as to provide flexibility of said series of disks.

References Cited in the file of this patent UNITED STATES PATENTS 972,769 Lark Oct. 11, 1910 1,928,158 Ruse Sept. 26, 1933 2,017,300 Wiesman Oct. 15, 1935 2,548,311 Johnson Apr. 10, 1951 2,854,180 Brunckhorst Sept. 30, 1958 2,969,126 Gardner Jan. 24, 1959 FOREIGN PATENTS 147,367 Australia Jnly 16, 1952

Claims

1. AN ADJUSTABLE LEG DEVICE FOR A LADDER COMPRISING A TUBULAR GUIDE ADAPTED TO BE FIXEDLY SECURED TO THE LOWER END OF A LADDER, GENERALLY PARALLEL LEG PORTIONS ON SAID GUIDE, A TELESCOPIC LEG IN EACH OF SAID LEG PORTIONS, A FOOT ON THE OUTER END OF EACH TELESCOPIC LEG, A RESILIENTLY FLEXIBLE LINE EXTENDED THROUGH SAID GUIDE, MEANS TO CONNECT THE ENDS OF SAID LINE TO THE RESPECTIVE TELESCOPIC LEGS FOR MOVEMENT WITH SAID TELESCOPIC LEGS IN OPPOSITE DIRECTIONS ACCORDING TO THE ADJUSTMENT OF SAID TELESCOPIC LEGS RELATIVELY TO SAID GUIDE, A CURVED PORTION ON SAID GUIDE BEYOND THE LIMIT OF TELESCOPIING OF SAID TELESCOPIC LEGS, A LOCKING KEEPER DEVICE FIXED IN SAID CURVED PORTION, LOCKING ELEMENTS ON SAID LINE ADJACENT SAID LOCKING KEEPER DEVICE NORMALLY HELD BY SAID LINE OUT OF ENGAGEMENT WITH SAID LOCKING KEEPER DEVICE, SAID LINE BULGING IN SAID CURVED PORTION WHEN BOTH TELESCOPIC LEGS ARE PRESSED INWARDLY OF SAID GUIDE SIMULTANEOUSLY THEREBY TO INTERLOCK SAID LOCKING ELEMENTS WITH SAID LOCKING KEEPER DEVICE, AND SPACER MEANS CONNECTED TO SAID LOCKING ELEMENTS TO RESTRAIN THE TELESCOPING OF SAID TELESCOPIC LEGS WHEN SAID LOCKING ELEMENTS ARE IN INTERLOCKING POSITION, SAID LOCKING ELEMENTS BEING STRUNG ON SAID LINE AND HAVING HOLES THERETHROUGH FITTING ON SAID LINE SO THAT THE BULGING OF SAID LINE PUSHES SAID LOCKING ELEMENTS OUTWARDLY AGAINST SAID KEEPER DEVICE AND THE CONTRACTING OF SAID LINE PULLS SAID LOCKING ELEMENTS AWAY FROM SAID KEEPER DEVICE, SPACED PROJECTIONS FORMED BY SAID LOCKING ELEMENTS PROJECTING TOWARD SAID KEEPER DEVICE; SAID KEEPER DEVICE INCLUDING SPACED RECESSES INTERENGAGEABLE WITH SAID SPACED PROJECTIONS; AND SAID LOCKING ELEMENTS BEING ADAPTED TO FOLLOW THE CONTOUR OF SAID GUIDE WHEN MOVED THEREIN.