US2517771A

US2517771A - Extension shoe for ladder legs

Info

Publication number: US2517771A
Application number: US24553A
Authority: US
Inventors: Stefano Vincent De
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-05-01
Filing date: 1948-05-01
Publication date: 1950-08-08
Anticipated expiration: 1967-08-08

Description

Aug. 8, 1950 v.- DE SIEFANO EXTENSION SHOE FOR LADDER ms 2- Sheets-Sheet 1- Fled May l, 1943 INVENTOR VINCENT DE STef-nmo ATTORNEY v. DE STEFANO EXTENSION sHoE FoR LADDER LEGS Aug. `8, 11950 2 Sheets-sheet E Filed May l, 1948 INVENTOR VINCENT DE STEFANO lATTO RN EY Patented Aug. 8, 1950 UNITED STATES PATENT oEFlcE EXTENSION SHOE FOR LADDER LEGS Vincent De Stefano, Union City, N. J.

Application May 1, 1948, Serial No. 24,553

(Cl. 22S-453) 2 Claims. l

This invention relates to an extension-shoe for ladder legs.

In many cases it is necessary for 'painters and other Workmen to erect ladders `upon uneven sur faces, such as steep hillsides, and it is usual Vfor the 'workman to equalize the length thereof by placing checks under one of the two legs so as to permit the ladder to be placed and maintained in an upright or vertical position. This prac. tice, however, is dangerous and various proposals have heretofore been made to eliminate or avoid such `use of `chocks and to compensate for the uneven surfaces by the fastening on the ladder 'legs of V'extension members of various types, al1 of which are unsatisfactory in one way or another.

One of the objects of this invention is to pro-V vide a novel extension-shoe which is adapted 4quickly upon erection of the ladder to be automatically adjustable to fill the space beneath a ladder rail or leg which is required to compensate for the uneven surface on which the `ladder is molinted.

Another object of my invention comprises the provision `of an extension-shoe With novel fastoning means for mounting and securely fastening it onta ladder leg to enable Athe shoe to be easily and instantly applied `to and removed rfrom the lower end portion of veither one of the legs or rails of the ladder.

Another object of my invention 'is to 'provide an extension shoe with unitary quickeiastening means which is capable of securelywfastening the shoe to the .ladder Without the` use` of bolts and like fastening elements, andvwhich when so fas tened to a ladder leg may be positively, effectively and safely adjusted to extend `and lengthen said leg -in order to enable the ladder to be firmly `and securely positioned and held in a vertically-disposed upright position and thus to avoid and i prevent any movement, falling or inclining of the ladder during use when mounted as aforesaid on suc-h uneven surfaces.

Another object of my invention is to provide `an adjustable extension shoe for `lad-der rlegs of the character specified which, upon erection of the ladder, may be readily 4and easily manpu lated to provide adjustment of the `extension to firm contact with an `uneven surta'ce on which the ladder is being mounted.

Another object of 'my `inventionpis in an adjusta-ble extension shoe for ladder legs to combine with a relatively stationary member proffen ably comprising a tubolari sleeve Aadapted 'to embrace thetlowereportlon orthelegvorrail ci a ladder, a unitary rung-embracing fastening device which extends at a right angle to said sleeve member and is adapted to embrace and be locked to a portion of the first rung of the ladder, thus providing for the secure fastening of said stationary sleeve to the ladder leg embraced thereby 'and also to combine with said stationary sleeve member an extensible element, which preferably comprises a telescoping tube member adapted automatically to drop to the ground and to compensate by immediate extension for the degree of nnevenness of the terrain or ground upon which the ladder is being mounted.

Another object of my invention is to provide a device of the character specified in which `the extensible member is maintained in interengaging position by a rack and pawl mechanism having the teeth inclined downwardly to permit im.- mediate automatic movement and compensation upon release of the pawl, and to produce an interlocking engagement of said pawl with Said teeth by the provision of an operating element having suiiicient leverage and strength to cause retention of the parts in such a given initial position 'as tc permit ready handling of the ladder` with the device in place thereon but to enable quick auto-matic adjustment of the extension member to the required degree. i

Still another object of my invention is to produce a device of the character specified embodying a pair of telescopic tubular leg-embracing members having rack and pawl connection, combined with means for fastening one of said members and additional means for controlling said rack 'and pawl connection to permit instantan'eo'us automatic extension or collapsing.

`nother object of my invention is to provide, in combination with` a pair of telescopic tubular members, a cylindrical rung fastening sleeve having an openable hinged top for ready and immeL dia-te connection with the rung of the ladder Without the use `of bolts or like `fastening devices.

"ormance of the functions and the accomplish 'mentor the results herein contemplated, `and comprises in one of its adaptations the species or preferred form illustrated in the accompanying drawings, in which:

Fig. 1 is a view in front elevation of a ladder showing my adjustable extension shoe member fastened to one of the legs thereof;

Fig. 2 is an enlarged sectional View on the line 2--2 of Fig. l, looking in the direction of the arrows;

Fig. 3 is a transverse section on the line 3-3 of Fig. l, looking in the direction of the arrows;

Fig. 4 is a rear elevation of the device shown in Fig. 2 as viewed from the line 1 -ll of Fig. 2, looking in the direction of the arrows; and

Fig. 5 is a section on the line 5 5 of Fig. 4.

Referring now to these drawings which illustrate a preferred embodiment of my invention, the extension shoe for ladder legs illustrated comprises a pair of telescopic tubes which in telescoped condition are adapted to be slid or moved upwardly on either one or the other of the lower leg-sections 3a of a workmans ladder 3. The telescoping tubes comprise an inner-tube member I adapted to be xedly connected or fastened to one of the lower ladder-sections and an outer tube member 2 carried by the inner tube-member and having a readily-releasable rack and pawl connection therewith whereby manual release of the said connection will cause an automatic dropping by gravity of the outer member 2 and a. consequent extension of the shoe, the bottom portion 2a of which will thereupon Contact with the ground or terrain on which the ladder 3 is being erected.

My preferred means for fastening the member I to the ladder section 3a comprises a laterally projecting cylindrical sleeve 5 xedly carried by the member I and having an openable hinged cover or top E adapted to be swung into open position when the complete device is moved upwardly on the leg 3, whereupon it will Contact with the first rung 'I and upon a closing of the hinged cover or top 6 will engage and embrace said lowermost rung 'l of the ladder 3, as shown more particularly in Figs. i and 3. As illustrated, the hinged top 6 is opened as illustrated in dotted lines in Fig. 2 during the connecting or attaching movement and then is swung into closed position over the inner section of the rung 1, whereupon a locking pin 8 is inserted into aligned grooves 9, 3a at the edges of the top and body portion of the sleeve 5. This swinging of the hinged cover or top E into closed position and the placing of the locking pin 8 into the grooves 9, @a securely fastens the entire device in place on the ladder.

The tube members I and 2 are preferably rectangular in cross-section to nt the ladder-leg and the outer member 2 ts closely over the inner member I and the relatively stationary innertube member I carries on its rear face a vertically-disposed toothed rack Iii, while the outertube member 2 is provided at its upper end with a pivoted pawl II. As shown, the pawl II is pivoted on a pivot M and is formed integrally with a mounting frame I2 which extends for- Wardly to the front end of the ladder and is provided with an operating handle I3. The pivot I4 is mounted in mounting ways I5 and the mounting frame and integral handle are pivotally mounted on said pivot I4.

The rack I has teeth Illa that incline downwardly and are preferably slightly undercut while the pawl II is upwardly-inclined and has an incline-engaging surface provided with an inclined pitch that fits the downwardly inclined 4 surface of the rack teeth while the top surface of the pawl which contacts with the bottom of the undercut teeth preferably is slightly inclined to fit the undercut surface of said teeth.

The pivot I4, as shown, is mounted in the frame I2 which extends outwardly to the front face of the member 2 in substantial parallelism to the upper edge of said member 2 and said pivot I4 extends parallel to and spaced from the rack so that the pawl il projectsupwardlysand inwardly at an acute angle to the pivot I4 to provide the tooth-contacting inclination above specied.

The pawl-mounting frame I2 and handle are f heavy enough normally to keep the pawl II in interlocking engagement with the toothed rack IG. When, however, it is desired to extend the device to compensate for an uneven ground surface on which the ladder is to be erected, the handle I3 is lifted and the outer tube 2 instantly slides downwardly by gravity to a suitable position in contact with the ground and thus `to close the space between the bottom of the ladderleg on which the device is mounted and the ground.v The mounting frame is normally held by gravity in horizontal position to press the pawl II against the teeth of the toothed rack IG and thus to lock the two tubes in collapsed position, and when the handle is lifted, the mounting frame and pawl will cause release of the pawl and the tube-member 2 will drop as aforesaid. The normal position of the mounting frame, pawl and rack will be clearly seen in Figs. 2 and 5 and the released position will be seen in dotted lines in Fig. 2.

In the apparatus shown, the bottom of the lower tube is provided with a semicircular band of saw teeth which are intended to bite into the ground and assist in prevention of slipping of the ladder. It will be seen that my relativelymovable telescoping tubes provide for gravityactuation to enable instantaneous adjustment, and that the cylindrical rung-fastening sleeve having an openable hinged top for connection to a rung 'I provides a quick, simple and integral fastening means for the device.

IThese telescoping tubes are preferably of less length than the ladder-leg sections to which they are applied so as to enable more ready handling of the ladder during erection, but the extension of the movable member causes the ladder leg to be lengthened much beyond the leg section to which it is applied, and may thus be used to compensate for abruptly sloping ground, as for example when a painter or workman is painting a house on a steep hillside.

In operation, when a workman is working on a hillside, the ladder with my extension shoe mounted thereon will be moved to the site of 'erection and placed into a proper straight position relatively to the building or other structure which isbeing worked upon. Upon erection in such position, an upward movement of the handle I3, which may be effected by the foot of the user, will release the Ipawl carried by the outer member fromthe rack on the inner member and vcause thev outer member to drop by gravity and to contact the low ground portion and thus to automatically compensate for the ground-drop or difference required in length of the extension leg to reach such ground. Should adjustment be necessary, this may be readily accomplished by manipulation of the said handle.

Having described my invention, I claim:

l. An extension` shoe for ladder-legs. comprising inner and outer members, said inner member having unitarily connected thereto a laterally projecting rung-engaging sleeve adapted to embrace a portion of the ladder rung and composed of a body-portion and openable hinged cover, said body portion and cover having interconnectable means for fastening said cover to said body portion to enclose said rung portion and to fasten said sleeve and extension shoe to the ladder, and means for extending the outer member in relation to said inner member.

2. An extension shoe for ladder-legs comprising a pair of telescoping tubes adapted to t over the ladder-leg section below the bottom rung thereof, means for fastening the inner telescoping tube to the ladder and releasable means comprising a toothed rack on one member and a pawl on the other member mounted to engage said rack and to be releasable therefrom to cause the dropping of the outer member by gravity, said rack being provided with teeth inclined downwardly and outwardly and the paWl being pivotally mounted in spaced parallel relationship to said rack to extend upwardly at an angle substantially similar to the inclination of the teeth of the rack and to engage said teeth at its tip, said pawl being formed integrally with a pivot-mounting frame extending around the outer member of the extension shoe and having at said opposite face an operating handle, said frame and handle having suilicient weight to retain said pawl in normal engagement with the teeth of the rack and to permit ready manipulation for release of the pawl therefrom.

VINCENT DE STEFANO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Q0 Number Name Date 971,997 Henning Oct. 4, 1910 2,458,076 Houston T--- Jan. 4, 1949