US1083744A - Step-ladder. - Google Patents

Description

D. JONES.

STEP LADDER.

APPLIOATION PILED mso. 12, 1912.

Patented Jan. 6, 1914 DAVID JONES, OF APPLEGATE, CALIFORNIA.

STEP-LADDER.

nasema.

Application filed December 12, 1912.

Specification of Letters Patent.

Patented Jan. 6, 1914.

Serial No. 736,274.

To all wiom it may concern Be it known that I, DAVID JONES, a citizen of the United States, residing at Applegate, in the county of Placer and State of Califor-nia, have invented certain new and useful Improvements in Step-Ladders of which the following is a specication, reference being had therein to the accompanying drawing.

This inventio n relates to step ladders adapted more especially for hillside use or where the ground or surface where the ladder is placed is uneven, and the invention has to do particularly with step ladders of the type disclosed in the United States Letters Patent No. 766,385, granted August 2, 1904, to O. Richardson.

It is the Object of the present invention to improve step ladders of the character disclosed in the said patent so as to render the same more firm and stable and more reliable in use. -In the said patented step ladder, only one lateral prop member of the supporting frame is clamped to the step frame of the ladder, whereas, according to the present invention both lateral prop members are clamped to the step frame.

Another Object of the invention is to provide a pair of clamps for the respective lateral prop members of the supporting frame, which clamps are simultaneously released or set.

With these and other objects in view, the invent-ion comprises the various novel features of construction and arrangement of parts which will be more fully described hereinafter and set forth with particularity in the claims appended hereto.

In the accompanying drawing, which illustrates one embodiment of the invention, Figure 1 is a perspective View of a step ladder equipped with the invention. Fig. 2 is a rear view' of the lower portion of the step frame with the supporting frame shown in one position by full lines and in a reverse position by dotted lines.

Similar reference characters are employed to designate corresponding parts throughout the Views.

Referring to the drawings, A designates the step frame of the ladder; B, the prop pivotally connected or hinged at its upper tremity 1 to the top or head of the step frame, and on the lower part of the step frame is the supporting frame C. There is no novelty in the step frame prop, so that a detail description thereof is unnecessary.

The supporting frame eonsists of two lateral prop members 2 and 3, which are near their lower extremities connected by pivcts 4c with the extremities of an equalizing lever 5 which is fulcrumed at 6 on a cross bar 7 rigidly secured to the foot portion of the step frame. The upper ends of the members 2 and 3 are slidable in guides 8 and 9, respectively, on the ends of a cross bar 10 fastened to the rear side of the step frame A at a suitable height above the equalizing lever 5.

The feet members 2 and 3 are each provided with a clamping means at its guide so as to firmly connect the supporting frame C with the step frame A. In the guide 8 is a tooth, abutment or other fixed part 11 with which is adapted to engage a notched or rack bar or equivalent device 12 fastened to the inner face of the lateral prop member 2, the engagement of the rack bar with the tooth 11 being naintained by a clamping device consisting of a cam 13 pivoted at 14 between the guide or keeper 8 and the fixed bar 10, the said cam having a handle 15.* The other member 3 is positively engaged and held by means of a looking device consisting of a dog 16 which is fulcrumed at 17 on the fixed bar 10, the tooth 18 of the dog being adapted to engage a rack bar or equivalent device 19 fastened to the inner face of the lateral prop member 3. This dog hasa depending portion or arm 20 which is connected by a bar 21 with the cam 13 below its aXis, and consequently the looking cam 13 and dog 16 can be moved together to and from their positions by manipulating the handle 15.

In adjusting the ladder so as to set upright on an uneven surface, the handle 15 of the cam 13 is thrown to the left, Fig. 2, to the dotted line position, thereby causing the members 2 and 3 to be released. The said members of the supporting frame can then be shifted according to the slope of the surface on which the ladder is to be set up, it being understood that the rack bar 12 is out of line with the tooth or abutment 11 during this adjustment. The cam lever 15 is then thrown to the right, Fig. 2, so as to cause the cam surface to move the member 2 into engagement with the tooth or projection 11, and the tooth 18 of the dog 16 into engagement with the rack bar 19 and forcing the side member 3 against the guide or keeper 9. Consequently, both members 2 and 3 of the supporting frame are locked firmly with respect to the step ladder proper. The more weight imposed on either lateral prop member, the more tightly are both prop members held against longitudinal sliding movement.

From the foregoing description, taken in connection with the accompanying drawing, the advantages of the construction and of the method of operation will be readily apparent to those skilled in the art to which the invention appertains, and while I have described the principle of operation of the invention, together with the device which I now consider to be the best embodiment thereof, I desire to have it understood that the device shown is merely illustrative, and that such changes may be made when desired as are within the scope of the claims appended hereto Having thus described the invention, what I claim is 2- 1. The combination of a ladder frame, with an adjustable supporting frame comprising lateral prop members, means for movably Connecting the lower portions of said lateral prop members with the step frame, individual guiding means on the step frame for the upper ends of said lateral prop members, rack devices on the opposed faces of said lateral prop members, a fixed abutment on the step frame for engaging the said device on one lateral prop member, clamping means for holding the last named lateral prop member by engagement with the said fixed abutment, movable means on the step frame for engaging the rack device of the other lateral prop member, and a connection between the said clamping means and the said movable means for simultaneously releasing or clamping the same.

2. The combination with a ladder frame, of an adjustable supporting frame comprising lateral prop members, means for movably connecting said members with the ladder frame, rack devices on the opposed faces of said members, a fixed abutment on the ladder frame for engaging the rack device of one member, clamping means for holding the last named member by engagement with said abutment, moVable means on the ladder frame for engaging the rack device of the other member, and a connection between said clamping means and said movable means for simultaneously releasing or clamping the same. a

In testimony whereof I afliX my signature in presence of two witnesses.

DAVID JONES. r

Witnesses:

J. A. HAINES, ANDREW OLSEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patent, Washington, D. C."

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