US556831A - Extension-ladder - Google Patents

Description

G. WQH, MOULTON.

EXTENSION LADDER.

Patented Mar. 24, 1896.

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CHARLES \V. IL MOULTON, OF CAMBRIDGE, MASSACHUSETTS.

EXTENSION-LADDER.

SPECIFICATION forming part of Letters Patent No. 556,831, dated March 24, 1896.

Application filed November 6, 1895. serial No. 568,092. (No model.)

To all whom it may concern.-

Be it known that 1, CHARLES W. H. Moun- TON, of Cambridge, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Extension- Ladders, which will, in connection with the accompanying drawings, be hereinafter fully described and specifically defined in the appended claims.

In said drawings, Figure 1 represents parts of an extension-ladder with my invention thereto applied; and Fig. 2 is a sectional elevation, the section being vertical through the rungs shown in Fig. 1 and the view as from the left in Fig. 1.

My invention relates to an improvement in extension-ladders which are provided with pawls that secure the upper half at any desired position upon the lower half; and it con sists in a stay that supports the pivot-bolt and at the same time arrests the movement of the pawl when it is being revolved on said pivot, so that it cannot move beyond a vertical position when being turned up.

It also consists in so forming the lower locks of the ladder that said pawls when turned downward will be arrested when they reach the lowest point, so that they cannot revolve through more than a half-circle when the ladder is provided with my improvements.

Referring again to said drawings, A A rep resent the standards of the lower section of the ladder, the same being secured in position by the usual rungs a. The lower part of the upper section is shown at B B, which parts are united by rungs and shown at 2'. The pawls that hold the top sect-ion at the desired height are shown, as at D, but one being deemed necessary to be here shown. This pawl is pivoted upon bolt d, and it is formed with longer finger b, shorter finger c, and a counterweight 6, so that said top section can be raised and lowered by the automatic action of said pawls. As the striking of said pawls against. the rungs a causes them to be whirled upon their pivot, to the great inconvenience of the user, I form the lower ladder-locks O, which are riveted to the top section by rivet k, as shown, to extend inside pieces B, as shown in Fig. 1, far enough to arrest the pawl when it is thrown back by end of which said bolt (1 is inserted, while at the upper end said bar is bent at right angles and the short arm g is secured in part B, as shown. The length of barf is such that when pawl D is thrown up it is arrested by arm g, as shown by dotted lines in Fig. 2. By this construction of bar f, arm g, and bolt cl, the pawl cannot swing beyond arm g, and bolt (1 is secured firmly in place and cannot bend. Bar f and part 01 and 9 could all be formed as an integral piece, or both (1 and 9 may be inserted; but I prefer the construction shown.

Bolt cl is formed with a shoulder against which washer & bears, so that pawl D cannot be pinched between bar f and the sides B when the nut on bolt dis turned up, and the same provision is made at arm g, as SllOWll at z.

I claim as an improvement in extensionladders 1. In combination with the upper and lower sections of an extension-ladder and the pawl D by which the upper section is sustained at the desired height, the barf connected at its lower end with bolt that pivots said pawl, and at its upper end is provided with the short arm g secured to the side of said upper section, and so arranged as to support said bolt d, and to also arrest said pawl when it swings upward, substantially as specified.

2. In combination with the upper and lower sections of an extension-ladder and the pawl by which said upper section is sustained at the desired height, the bar f arranged to receive bolt (1 that pivots said pawl, and having an arm secured to said upper section so as to arrest the upward swing of said pawl, and the lock 0 by which said upper and lower sections are secured together, extended inside of part B of the upper section to arrest the downward swing of said pawl substantially as specified.

CHARLES WV. 11. MOULTON.

YVitnesses:

T. W. PORTER, M. E. Bownrron.

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