|Publication number||US161010 A|
|Publication date||Mar 23, 1875|
|Filing date||Jul 22, 1874|
|Publication number||US 161010 A, US 161010A, US-A-161010, US161010 A, US161010A|
|Inventors||Jambs M. Davis|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (3), Classifications (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
'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
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 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.
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3326507 *||Jan 3, 1966||Jun 20, 1967||Sears Robert L||Ladder jack|
|US5324086 *||Jul 13, 1992||Jun 28, 1994||Mordechai Hammer||Device capable of positive extension and retraction using a casading force transfer|
|WO1994001254A1 *||Jul 9, 1993||Jan 20, 1994||Friedman Mark M||Extendible and retractable device|