US1712435A - Extensible stepladder - Google Patents

Description

H. H-ILL EXTENSIBLE STEPLADDER May 7,1929.

Filed Feb. 18 1927 2 Sheets-Sheet l Patented May 7,

UNITED STATES "PATENT OFFICE.

EXTENSIBLE s'rEPLAnnnn.

Application filed February 18, 1927. Serial No. 169,329.

The present invention pertains to a novel step ladder adapted for use in the ordinary manner and also constructed so that the main and prop sections thereof may be brought into alinement to form a single ladder by which higher levels may be reached.

The principal object of the invention is in-- dicated 1n the foregoing statement and 111- volves ."lurther a device otthis Character constructed in a simple manner.

With this object in view, the prop rails of the construction are provided with rungs so that the user may climb these rungs when the ladder is extended. The invention includes also a spring device carried by the main section and adapted to act on the prop section in order to aid in bringing the latter into alinement with the main section. Further, the invention comprises, in combinationwith the step ladder braces, a pair of springs acting' on the pivot ends of the braces in such a manner as to secure them in operative position and also to assist in raising them when the ladder is to be extended.

The invention is fully disclosed in the following description and in the accompanying drawings in which:

Figure 1 is a side elevation of the ladder 1n extended form;

Figure 2 is a detail vertical section in a plane parallel to thatoi Figure 1;

Figure 3' is an elevation of the ladder arranged as a step ladder;

Figure 4b is a detail vertical section showll'lQf the brace and associated part.

lt ioure 5 a side elevation of the device c .s a step ladder; and

Figure 6 is a similar view of the device positioned for use as a short ladder propped against a wall.

Reference to these views will now be made by use of like characters which are employed to (insinuate corresponding; parts throughout. ll; will be apparent after a comparison of l iu'ures 1 and 5 that the device ofthe 1VG11- are preferable inordcr that the same form tread may be used throughout. The prop section in the step ladder assemto the inner faces of the rails 1. In line with the rails 3, spring strips 5 of the jack-knife principle are secured to the inner faces of the members 1. These strips 5 may be formed of spring metal or other suitable material and arranged so that the upper ends are disconnected for edgewise movement for re silient engagement with the rectangular pivot extension of the rails 3. The pivoted ends of the member 3 are notched as at 6 to receive the upper ends of the spring members 5. Finally the springs are concealed by additional strips 8 secured to the members 1 by the pivot pins 4 of the rails 3.

Over the top of the rails 1 is laid a top step 9 in the usual manner of step ladder construction. The rails 3 are joined together and held in spaced relation by rungs 10 secured between them. The peculiar relation between the notches 6 and the upper ends of the springs 5 permit the prop rails 3 to be swung upwardly and into alinement With the rails 1 whereby a single ladder is formed as shown in Figure 1. Thus, uniform rungs such as the members 2 and 10 may be used throughout the construction.

A further feature of the invention resides in the braces for securing the device in the position of an ordinary step ladder. These braces are designated in Figures 4 and 5 by the numeral 11. They are pivoted at one end to the inner faces of the member 8 as indicated by the numeral 12, whilethe remaining end of each member 11 has a slot 13 adapted to receive the opposite rung lO between the me1nhers 3. The pivoted end of each member 12 is engaged by a flat spring 14: also secured to the inner face of the adjacent member 8 by means of pins 15. hen the props are in use as in Figure 5, the pivoted extremities 16 thereof are engaged by the springs l l whereby the props are prevented from slipping off the rungs 10. Also, when these props are lifted from the rungs 10, the springs 14; act on the sides17 thereof and raise the members to the position shown in Figure 4;.

A similar action occurs when the rails 3 are aised to extend the ladder. The action of the springs 5 in the notches 6 aids in the upward travel of the prop section and further holds the two sections in alinement.

While a specific embodiment of the invention has been illustrated and described, it is to be understood that various alterations in the details of construction may be made without departing fromthe spirit of the invention as indicated by the appended claims.

7 Having thus fully described the invention, wh atI claim as new and. desire to protect by -Letters Patent is:

1. An extensible step ladder Comprising main ladder rails, treads between said rails, prop rails pivoted to the upper ends of said main rails and adapted for alinenient therewith, rungsprovided between said prop rails,

-' notches formed in the pivoted ends of said oro railsand s rin members' carried b l P a e e 3 said main rails and adapted for reception in said notehes in order to hold both sets of rails x .2p'Anextensible step ladder comprising a main ladder'section including a pair of longi tudinal side ra'1ls,treads'mounted transversely --between the said ra1ls,a prop section 1nc1ud ing a pair of side rails, treads mounted in transverse osition between the side rails one with the side rails, the upper ends of the strips I being arranged to resiliently engage the reduced pivot extensions of the prop section side rails so as to resiliently support the prop section when the same is arranged in co-extensive alignment with the main section.

In witness whereof I have hereunto set my hand.

HENRY HILL.

Images