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Publication numberUS161010 A
Publication typeGrant
Publication dateMar 23, 1875
Filing dateJul 22, 1874
Publication numberUS 161010 A, US 161010A, US-A-161010, US161010 A, US161010A
InventorsJambs M. Davis
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Improvement in extension-ladders
US 161010 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

'J. M. DAVIS. 1 Extension-Ladder.

Noflfil OIO PatentedMarch23J87 5" THE GRAPHIC COJKOTO ,-L|TH.39 8:41 PARK PLACLILY- UNITED STATES JAMES M. DAVIS, BANGOR, MAINE, ASSlGNOR TO JOSEPH S. SMITH, OF

PATENT OFFICE.

SAME PLACE.

IMPROVEMENT IN EXTENSION-LADDERS.

Specification forming part of Letters Patent No. 161.010, dated March '23, 1875 application filed July 22, 1874.

To all whom it may concern Be it known that I, JAMES M. DAVIS, of Bangor, in the county of Penobscot and State of Maine, have invented certain new and useful Improvements in Extension-Ladders; and I do hereby declare that the following is a full, clear, and exact description thereof, that will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, forming a part of this specification, in which- Figure 1 shows a front elevation; Fig. 2, a partial section.

Same letters show like parts.

My invention consists of an extension-ladder designed for the use of firemen, painters, and

I others.

I employ two or more ladders, the arrangement and operation of which will be readily understood by reference to the accompanying drawing.

At a is shown a stationary ladder, upon which is placed a sliding ladder, 1), moving in proper retaining-clamps 0. At each end of theon a shaft, *5, at the lower end of the sliding ladder, upon the ends of which shaft are hooks jj of sufficient length to hook over the rungs of the stationary ladder a, so as to support the ladder b at any desired point of extension. These hooks j j and the projection h upon the shaft i form a lever, l, of which said shaft is the fulcrum, which lever is operated by the chain g, sothat when the ladder c is being extended the hooks are hugged down toward the ladder or, clasping over its rungs, but when the ladder c is slid downward the lower portion of the chain lifts the hooks away from said rungs, allowing the ladder to descend without impediment. llhe upper faces of the hooks are curved outwardly, so as to pass easily over the rungs as the ladder ascends.

What I claim as my invention, and desire to secure by Letters Patent, is-

In an extension-ladder, the combination of two or more ladders with drums 0, chain g, and lever l, substantially as and for the purposes set forth. 7

In testimony that I claim the foregoing I have hereunto set my hand this 18th day of July, 1874.

JAMES M. DAVIS.

Witnesses WM. FRANKLIN SEAVEY, J. B. BASS.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3326507 *Jan 3, 1966Jun 20, 1967Sears Robert LLadder jack
US5324086 *Jul 13, 1992Jun 28, 1994Mordechai HammerDevice capable of positive extension and retraction using a casading force transfer
WO1994001254A1 *Jul 9, 1993Jan 20, 1994Friedman Mark MExtendible and retractable device
Classifications
Cooperative ClassificationE06C1/12