US887131A

US887131A - Counterbalance for lift-bridges.

Info

Publication number: US887131A
Application number: US41776808A
Authority: US
Inventors: Louis H Shoemaker
Original assignee: Individual
Current assignee: Individual
Priority date: 1908-02-25
Filing date: 1908-02-25
Publication date: 1908-05-12
Anticipated expiration: 1925-05-12

Description

PATENTED MAY 12, 1908.

L.'H. SHOEMAKER. GOU'NTERBALANGE FOR LIFT: BRIDGES.

APPLICATION FILED 133.25, 1908.

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No. 887,131. PATENTED MAY 12, 1908.-

L. H. SHOBMAKER.

GOUNTERBALANOE FOR-LIFT BRIDGES;

APPLICATION FILED FEB. 25, 190B.

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IINITD STATE% AENT @FFICE.

LOUIS H. SHOEMAKER, OF SEWIOKLEY, PENNSYLVANIA.

COUNTERBALANCE FOR LIFT-BRIDGES.

Application filed February 25, 1908.

T 0 all whom it may concern:

Be it known that I, LoUis H. SHOE- MAKER, of Sewickley, in the county of Allegheny and State of Pennsylvania, have invented a certain new and useful Improvement in Counterbalances for Lift-Bridges, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which Figure 1 is a side elevation of a tower and the lifting span of a bridge illustrating my' invention, the span being shown in its lowered position; Fig. 2 is a like view showing the span in its elevated position.

Like symbols of reference indicate like parts wherever they occur.

The object of my invention is to provide a counterbalance for the movable or lifting span of a bridge, which counterbalance shall exert a proper force to counterbalance the span at each of the various positions the span assumes during the lifting operation; that is, the greatest force is exerted in counterbalancing effort when the span is in its horizontal position, which force is lessened as the span is lifted to a vertical position, so that undue counterbalancing effort shall not at any time be exercised.

I will now describe my invention so that others skilled in the art may employ the same.

In the drawing, 2, 3, 4 represent the piers of the bridge. Supported on the

piers

2 and 3 is the tower 5 and extending between the piers 3 and. 4 is the lifting span 6 of the bridge, which span is pivoted to the tower 5 at the pier 3. The outer end of the span 6 rests on and is supported by the pier 4. Pivoted to the tower 5 is the radial arm or arms 7, at the outer end of which is a sheave 8. Mounted on the tower 5, preferably at the top thereof, is a sheave 9. Secured to the span 6 is a rope 10 which passes under the sheave 8' and over the sheave 9 and is se- Specification of Letters Patent.

Patented May 12, 1908.

Serial No. 417,768.

cured to a counterbalance weight 11 ar ranged to drop from the upper portion of the tower 5. The lifting span 6 may be raised and lowered by any suitable power mechanism. When the span 6 is in its lowered position, the weight 11 exerts its greatest effort in lifting force, but as the span rises from the position shown in Fig. 1 to the position shown in Fig. 2, the lifting effort of the weight 11 decreases in substantial ratio with the decrease at the resistance offered by the span as it assumes its vertical position.

The advantages of my invention will be appreciated by those skilled in the art. The

arts are strong and simple and not liable to get out of order and any injurious force or ,jar caused by the counterbalance during the lifting of the span is avoided.

Having thus described my invention, wh at I claim and desire to secure by Letters Patent is:

1. In a lifting bridge, the combination of a lifting span, a pivoted arm of less length than the length of the lifting span and provided with a sheave, an elevated sheave, a counterweight, and a line extending from the lifting span to'the sheave on the pivoted arm, thence to the elevated sheave and connected with the counterweight; substantially as specified.

2. In a lifting bridge, the combination of a lifting span, a pivoted radial arm of less length than the length of the lifting span and provided with a a sheave, an elevated sheave, a counterweight, and a line extending from the lifting span to the sheave on the pivoted arm, thence to the elevated sheave and connected with the counterweight sub stantially as specified.

In testimony whereof, I have hereunto set -85 my hand.

LOUIS I-I. SHOEMAKER.

Witnesses:

M. ARTHUR KELLER, M. A. BARTH.