US320671A

US320671A - Half to petee jeffeey

Info

Publication number: US320671A
Authority: US
Publication date: 1885-06-23
Anticipated expiration: 1902-06-23

Description

(No Model.)

J. MGG'OVERN.

GAISSON 0R CRIB.

No. 320,671. Patented June-Z3, 1885.

OgITNESSES mvnmon M W Y BY 7 ATTORMI N. PETERS. Fhowumo m her. Wuhington. D. c,

UNIT D STATES PATENT OFFICE.

JOHN MOGOVERN, OF MURPHYSBOROUGH, ILLINOIS, ASSIGNOB OF ONE- HALF TO PETER JEFFREY, OF SAME PLACE.

CAISSON OR CRIB.

SPECIPIOATIQN forming part of Letters Patent No. 320,671, dated June 23, 1885.

Application filed August 9, 1884.

(No model.)

To all whom, it may concern:

Be it known that I, JOHN MoGovERN, of Murphysborough, in the county of Jackson and State of Illinois, have invented anew and useful Improvement in Gaissons or Cribs, of which the following is a full, clear, and exact description.

The object of my invention is to facilitate the work of sinking coal shafts and wells and excavating for bridge-foundation in groundsuch as mud or quicksand-wvhich breaks into the excavation before it can be timbered.

It consists in a caisson or crib constructed and arranged for being sunk in advance of the main work, as hereinafter described and claimed.

Reference is to be had tothe accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in both the figures.

Figure l is a vertical section representing a shaft in process of construction with the caisson. Fig. 2 is a horizontal section.

The lower portion, A, of the crib is constructed of timber and of asize internally cor responding to the finished shaft. The lower portion is beveled to asharp edge, a, and shod with iron, so that it may enter the ground readily. The upper portion, B, of the caisson, formed of boiler-iron, is bolted to the part A on the outside, and is of a length to extend some distance upward outside the permanent timbering O of the shaft, so as to prevent mud or sand from running into the excavated space at the bottom. At D, on the inside of part B, are ribs taking against the timbering O, to insure equal space all around for inserting the timbers.

In using the caisson in the work of sinking a shaft it is gradually forced down by jackscrews placed, as shown at E, betweenthe top of the portion A and the lower course of the permanent timbers. It will of course be understood that in the soft ground in which the caisson is to be used the resistance to the screws will be less at the point a than it is at thebase of timber O. In other words, the timbers G cannot, owing to the character of the ground, he raised when the screws are operated, and it follows, therefore, that the point a will be forced downward. After being driven far enough to give space for a course of timber, the screws are removed, the material excavated enough to permit of the work, and the timbers then put in, after which the screws are again applied. The mud or sand is allowed to remain within the caisson up nearly to the top of part A and only removed as necessary, so that the caisson shall be held down to place.

By this mode of operating, shafts can be readily sunk in mud or shifting ground.

Having thus described my invention,[ claim as new and desireto secure by Letters Patent- The caisson or crib for use in sinking shafts, consisting of the timbered portion A, the extension B, ofboiler-iron, made large enough to inclose the permanent walls of the shaft, andthe horizontal ribs D, extending around the inner surface of the extension B, substantially as set forth.

JOHN MOG OVERN.

\Vitnesses:

THOMAS WATsoN, WILLIAM R. DAVIDSON.