US1729033A - Ladder - Google Patents

Description

Se t. 24, 1929.

Y J. F. CZISCHKE LADDER Fled Sept. 19. 1927 Patented Sept. 24, 1929 UNITED STATES JOHN FRED CZISCHKE,

OF CHICAGO, ILLINOIS LADDER Application filed September 19, 1927. Serial No. 220,309.

The invention relates to ladders and more particularly to extension devices for use in connection with the legs of the ladder-frame of a stepladder.

Stepladders are often employed for painting, window-washing and other such operations. When the object sought to be reached by means of the ladder is disposed above a stairway or step, the ladder is generally use- M less because the legs of the back-frame are supported at a higher elevation than the legs of the ladder-frame and consequently the ladder is inclined at an angie with respect to its normal or operatve position. In practice, 1.3 boxes are sometimes used for supporting the legs of the ladder-frame so as to meet or overcome this situation. However, such an arrangement is not practical, because the box upon which the ladder is supported often is 32;) not of the proper dimensions or is displaced from under the ladder with dire consequences. One object of the present invention is to provide a pair of devices which are adapted to be readily secured to the legs of the ladder- :3..3 frame of a stepladder and are operable as extensions to support the ladder-frame atdif ferent elevations. Vith these devices, it is possible to adapt the stepladder for use upon a stairway or step and by adjusting one of g:r) the devices relatively to the other, it is possible to use the ladder upon uneven ground. Another object of the invention is to provide a pair of devices of this character which are novel in construction and embody a comparatively few number of parts so that they may be manufactured at a low cost.

Other and incidental objects will appear hereafter from the detailed description.

The invention consists in the several novel features hereinafter set forth and more particularly defined by the claims at the conclusion hereof.

In the drawing which forms a part of this disclosure: Fig. 1 is a perspective view of a stepladder equipped with a pair of devices embodying the invention. F ig. 2 is a plan view of one of the devices. Fig. 3 is a longitudinal sectional view taken on line 33 of Fig. 2. Fig. 4: is an enlarged transverse sectional view taken on line 44 of Fig. 2.

The invention is exemplified in connection w1th a stepladder which may be of any suit able or well-known construction. The ladder illustrated in the drawing comprises a top or connecting member a, a ladder-frame b, and a back-frame c. The top member consists of a rectangular board a having attached to the under face thereof a pair of pvot brackets a The ladder-frame consists of a pair of side bars Z), the upper ends of which are rigidly secured to the board a and brackets a by bolts b and steps Z) which extend between the side bars-and are secured in place by screws b which extend through said sidebars. The back-frame c consists of a pair of side bars 0, the upper ends of which are pivotally connected to the brackets a by means of bolts or studs c and a pair of crossed braces 0 which connect the side-bars together for conjoint movement, A pair of.link-connections d are pivotally connected to the side-bars of the frames by studs cl. and serve to prevent outward movement of the back-frame relatively to the ladderframe beyond a certain predetermined distance.

The devices which form the subject mat ter of the present invention are adapted to be connected to the lower ends of the sidebars b and are operable as hereinbef0re stated to support the ladder-frame at different elevations. Each device comprises an elongated base-member 5 which is provided at its ends with countersunk holes 6 for wood screws 7 whereby the member may be fixedly secured in a longitudinal position to the lower end of one of the side-bars b. Each device also compr1ses an extension-member 8 which is substantially equal in length to the base-member and is slidably connected to the latter between a pair of guide-strips 9. These strips are suitably secured to the outer face of the base-member and permit the extension-member to slide longitudinally either toward or away from the side bar so as to increase or decrease the operative length of the latter. TO prevent lateral displacement, each extension-member is provided at its sides with ribs 10 which fit into grooves 11 which are formed in the inner faces of the strips. Each member 8 is held in its assigned position by means of a latch 12. The latter is provided at its sides with a pair of outwardly projecting lugs 13 which respectively cooperate or interlock with a pair of series of open-ended slots 14 which are formed in the outer faces of the guide-strips 9 and extend longitudinally with respect thereto. The slots of each series are spaced a suitable distance apart, such, for eX- ample, as an inch, to permit the extensionmembers to be locked in substantially any dcsired position with respect to the base-member 5. Each latch is disposed in a recess 15 which is formed in the upper end of the 6X tension-member to which the latch is attached and is mounted for pivotal 'movement so that the lugs may be swung out of interlocking relation with the slots when it is desired 'to shift the extension-member. The pivotal con nection for each latchcomprises a tongue 16 which is disposed in a transverse slot 17 and a pin 18 on whichthetongue is mounted. The pins extend transversely and are suitzibly mounted in the extension-members. To fa cilitate movement of the latches, handles or kn0bs '19 are provided. These handles project outwardly and are suitably secured to the latches. When it is desired to shift the extensiommembers so that the ladder-frame will be held at a predetermined elevation, the latches 12 will be swung outwardly to disengage orunlock the lugs'13 from the slots in which they are disposed. This renders the extension-members free to be slid into any position desired Vhen such position is reached, the latches willbe pressed inwardly to lock the extensionmembers in place.

To prevent the latches from being accidently displaced, springs 20 are provided. These springs are anchored to "the extensionmembers adjacentthe tongues 16 by screws*2l and are arranged sothattheir operative force is appliedto press the latchesinwardly. The springs are preferably of the flat metal type. To prevent the extensionmembers from being slid outwardly too far for-practical pur poses, steps 22 are provided. These stops are in the form of bars which extend across and are securedto the guide-strips 9. The bars are disposed in the path of the handles or hooks 19 so as to cooperate with the latter. The lower ends of the extension-members are rounded, as at 23, and are ribbed as at 24, to prevent them from slipping. A groove 25 is formed in'the back face of each base-member 5 to faccommodate the heads of the screws I).

While the devices have been described as being adapted'for use with a stepladder, it is to be 1inderstood that they may be used with a ladder or extension ladder so as to adapt the latter for use on uneven ground. This may beaccomplished by adjusting one of the extension-members relatively to the other to fit into depressions, etc., in the ground.

The invention exemplifies devices which may be applied as units to stepladders and the like and are operable as extensions. The invention also exemplifies devices of this character which are simple in construction and embody only a oomparatively few number of parts.

The invention is not to be understood as restricted to the details set forth, since these may be modified within the scope of the appended Claims, without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. A device for the purpose specified comprising a base provided with means whereby it may be secured to one end of a ladder and a pair of guide-members, an extensionmem ber slidable between the guide-iiiembers, each of the latter having a longitudinal series of open ended slots formed in one face thereof, and a latch pivotally connected to the extension-member-and provided with a pair of laterally pr0jecting lugs adapted to interlock with the slots to secure the eXtension-member in an assigned position.

2. Adevice for the purpose specified comprising a base provided with means whereby it may be secured to one end of a ladder and a pair of guide-members, an eXtension-member slidable between said guide-members, eachof the latter having a longitudinalseries of open-ended slots formed in one -facethere of, a latch pivotally connected to the extension-member and provided with a pair of laterally pr0jecting lugs adapted to interlock with the slots to secure said extension member in an assigned position, said latch hav ing an outwardly extending handle adjaeent the lugs whereby it maybe manipulated into and out of its operative position, anda cross bar secured tothe guide members at one end of the base and cooperable with the handle on the latch for limiting the sliding move ment of the extensionmember in-one direction. 1/9Signed at Chicago, Illinois, September,

7. JOHN FRED CZISCH KE.

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