US136278A - Improvement in lifting-bridges - Google Patents

Description

WITNESSES:

zsheetS--sheem S. SWABTZ. Lfing-Bridges.

Patented Feb. 25, 18.173.

WWINVENTOR:

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S.v SWABTZ.

Lifting-Bridges.

PatentedlFeb. 25,1873.

NOQ 136,278.

INVENTOR:

'UNITED I STATES PATENT?? OEEICEn SAMUEL SVARTZ, OF BUFFALO, NEW YORK.

IMPROVEMENT IN LIFTINGIBRIDGES.

Specification t'orn'iing part of Letters Patent No. 136,278, dated February 25, 1871.

To all whom 'it may concern:

Be it known that I, SAMUEL SWARTZ, of Bu'alo,fin the county ot' Erie, New York, have invented an Improved Liftin g-Brid ge, of which the following is a specification:

Nat/ure and Objects of the Invention.

This invention, although applicable to drawbridges in general, is more especially designed for those used on canal-slips and like narrow water-ways; and the invention comprises an improved plan for counterbalancing and lift- Y ing the bridge proper. The invention further comprises a means for supporting or securing the bridge in any desired position.

The construction and arrangement of the bridge is primarily intended to obviate any obstruction to the tow-line as applied to canalslips.

Dcscriptfion of thc Drawing.

Securely xed in the bank of the canal, and on one side of the slip to be spanned, are two posts or stanchions, a little more distant from each other than the width ofthe bridge proper. Ot' these stanchions one,which, in the present illustration, is composed, in fact, ot' two similar posts, A A', is arranged on the inner side ofthe tow-path, and has an altitude about equal to half the length ot' the bridge. The height of the other post, B, is just sufficient to aordjournal-bearing for one end of a pivot-shaft, O, whose other end has journal-bearings in the post A. To this shat't C is firmly attached the "heel7 end of a suitable trussbridge, preferably of the form represented at D. Projecting rectangularly or nearly rectan gularly downward from the shaft C are arms E E', from which struts F F' proceed directly to the under side of and near the mid-length of the bridge, where they meet and coact with truss-rods Gr G', which constitute members of the bridge. The ends of the struts F F' ,which pass through the arms E E', are screw-threaded to receive nuts fj", by means of which the said struts may be shortened or lengthened, so as to bring said struts to their proper strain and tautness, and to compensate for any torsional yielding of the shaft, or for any sag of the bridge proper, so as to maintain the remote corner n of the "toe or free end ot the bridge at its proper elevation relative-ly to the other parts ot' the bridge. This support or distribution of the strain andlitting-pressure may be still further aided and secured by diagonal planking, as shown in Fig. 1. Projecting upward from the shaft C is a semicircular ratch et, H, all of whose teeth h, save one or two, h', on the inner end, have their points directed reverse] y to the ascending rotation of the bridge, so as to enable the retention of the bridge at any desired elevation, or in horizontal position, by means of a catch-pawl, I, which has two claws, J J', ot' which claws one claw, J, is capable of being engaged in the teeth h and the other claw of being engaged in one ofthe teeth h', according as the handle I is thrown outward or inward. When the said handle I is Ain the vertical position neither one of its claws is engaged, and the bridge is then at liberty to be either elevated or depressed. The pivot-shaft G is also provided with a seg ment spur wheel or rack, K, in which gears a pinion, L. The shaft of this pinion is provided with a crank, M, by means ot' which the bridge is raised and lowered. The posts A A' have pivoted between them, near their upper ends, a balance-beam, N, whose length about equals that ot1 the bridge proper, and whose inner end is connected, by a chain, cable, or rod, O, with a wrist, P, which projects from the bridge proper near its mid-length and below its center of gravity. From the other end of the beam'y N depends a chain, cable, or rod, Q, which is weighted with a counter-balance, lt.

Upcfratt'on.

yproaches the entirely-open position, at which stage the preponderating portion of the bridge above the wrist, coming in aid of the counterbalance, now operates to hold the bridge in the elevated or open position, as shown in Fig. 2. y

lt will be seen that the struts F F', with their nuts ff', acting in conjunction With the truss-pieces G G', enable the lifting action on the wrist P at the middle of one side of the bridge proper to be transmitted equally to both sides of the bridge, and be effective at the end of the same remote from the pivot-shaft. It will also be seen that the bridge may be lifted and held as long as necessary at any height.

I am aware that a draw-bridge Working on a horizontal pivot and counterbalanced to facilitate lift-ing it is not new; and this I disclaim.

Claims.

.l claixn as new and of my i nventionl. The horizontal pivot-shaft G with arms EE@ the pivoted bridge D,ythe struts F F', the lifting mechanism K LM, and the balancevbeam N with the counter-Weight R, arranged,

G G', substantially as described.

3. The provision, on thepivot-shaft of a drawbridge, of the ratchet H h h', in the described combination with the catch-pawls I J J'.

SAMUEL SWARTZ.

YVitnesses:

BENJ. H. AUsTIN, Jr., ARTHUR W. HICKMAN.

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