US692117A - Marine propulsion. - Google Patents

Description

N0. 692.,"7. Patented lan. 28, |902.

I. MCK. CHASE.

MARINE PRUPULSION.

(Application led Jan. 29, 1896.)

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No. 692,7. Patented lan. 28, |902.

I. MGK. CHASE.

MARINE PBOPULSION.

` (Application Bled Jan. 29, 1896.)

(Model.) 2 Sheets-Sheet 2.

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ifa/.M JW( 4M UNHED STATES PATENT OFFICE.

ISAAC MCKIM CHASE, OF lVA-SHINGTON, DISTRICT OF COLUMBIA.

MARINE PROPULSION.

SPECIFICATION forming part 0f Letters Patent NQ. 692,117, dated January 28, 1902.

Application led January 29, 1896. Serial No. 577,227. (Model.)

To @ZZ whom it may concern:

Be it known that I, ISAAC MCKIM CHASE, a citizen of the United States, residing at Washington, in the District of Columbia, have invented certain new and useful Improvements in Marine Propulsion; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My present invention relates to the propulsion of marine vessels, has especial reference to screw-propellers, with the object of utilizing the energy of the water displaced by the screw, and consists in certain improvements in'construction, which will be fully disclosed in the following specification and claims.

In the accompanying drawings, which form part of this specification, Figure l represents a side elevation of my invention applied to a vessel; Fig. 2, a rear end view of the inven-` tion detached from the vessel and on an enlarged scale; Fig. 3, a top plan view of the same; Fig. 4, a rear end view of the propeller detached, and Fig. 5 a transverse longitudinal section through one blade of the propeller and one of the guide-blades of the bracket.

A submerged screw-propeller when revolving always discharges the water upon which it Operates with a more or less rotary motion and frequently with considerable velocity. This motion :represents a percentage of the energy which the engine has developed in giving the propeller motion, and in the prevailing practice this energy is allowed to go to waste in the course of the water regaining its normal condition. Several expedients have been proposed to recover the energy contained in the water discharged by a screwp'ropeller and to utilize it to augment the thrust. The most promising of these are guide-blades placed aftor behind a screw and upon which the Water impinges when leaving the screw. It has been proposed to apply a number of radiating blades set some distance aft of the screw and so formed as to receive the obliquely-movin g streams of water iiowing from the screw and turn them directly astern. It has also been proposed to use a guide-blade in the form of a twisted rudder, the part above the screw curved in' one direction and the part below in the Aopposile direction. One of the most successful applications of the guide-blade principle is in a device which consists of a cylinder secured to the vessel. Within the cylinder is a body or boss of such shape that the channel is gradually contracted from theforward to the after end. Within the forward part of the cylinder there are revolvingscrewblades attached to the forward part of the boss and is separate from the after part.

Aft of the revolving blades are numerous guide-blades of contrary or opposite curvature, which are fixed lo the rearward portion of the boss and to the cylinder. The screw is made unusually long, which produces considerable rotary motion in the discharged water; but in neither of these constructions has the water displaced by the screw been directed immediately against the guide-blades in such manner as to obtain the energy of the water in imparting thrust to the vessel. While guide-blades are of undoubted utility when properly applied, they have not been extensively used, owing to difficulties encountered in their practical application.

The device hereinafter described is de signed to overcome the difficulties heretofore found to exist in the application of guideblades to a screw-propeller and augment the efficiency of the propelling apparatus, especially in its application to twin-screwvessels. To accomplish the object of this invention, the bracket-bearing for the propeller-shaft is placed aft of the screw and is provided with guide-blades, which constitute a part of the bracket and which are so arranged with relation to the screw that they overhang or overlap and envelop or surround the blades of the screw to about the longitudinal median line of the propeller and aft of said line.

' The guide-blades may, howeveri7 be continued IOO object that will be an obstruction to the free ilow of water to a propeller will cause a diminution in its efficiency.

Reference being had to the drawings and the letters thereon, A indicates a marine vesj sel, and B a screw-propeller of any approved form; C, the propeller-shaft, which is supported at its forward end in a suitable bearing a and at its after end in a bracket D. The pitch and curvature of the blades b of the screw may be varied to suit circumstances.

The -bracket D is provided with guideblades c of a diameter substantially equal to the diameter of the screw and which project forward beyond the face of the hub cl of the bracketoverhang or overlap, and envelop or surround the propeller to the longitudinal median line thereof, as shown in Figs. l and 3, and the guide-blades are preferably of a pitch and curvature approximating those of the blades of the screw, but set in a direction opposite thereto, so that the water displaced by the blades b of the screw (and to which a more or less rotary motion has been imparted) impinges directly upon the blades c ofthe bracket D, imparting the energy contained in the water to the blades of the bracket and thrust to the vessel and also arresting the rotary motion of the water and restoring it to its normal condition. In the construction speedily.

eeail'r side of the stern of a` twin-screw vessel with the `bracket D in its relative position to the screw B; but the guide-blades may beapplied to a single screw by supporting a bracket on the end of the keel of the vessel or upon the stern.

Having thus fully described my invention, what I claim is- 1. A screw-propeller, in combination with fixed guide-blades aft of, overhanging, and extending forward to a point within the length of the screw.

2. A screw-propeller, in combination with fixed vguide-blades aft of, surrounding, extending forward and terminating at approximately the longitudinal center of the screw.

3. A screw-propeller, in combination with fixed guide-blades aftvof the screw and Vhaving a pitch and a curve from 'the root to the tip of the blade approximating the pitch and curve of the screw. l

et. A serew-propeller, in combina-tion with fixed guide-blades aft i of, overhanging the screw and approximating the diameter of the screw.

5. A screw-propeller, in combination with a bracket provided with guide-blades, aft of the screw and supporting one end of its shaft.

6. A screw-propeller, in combination with a bracket provided with guide-blades having a pitch approximatingthe pitch of the screw, aft of and supporting the screw.

7. A screw-propeller, in combination with a bracket provided with guide-blades having transversely-curved or oblique outer surfaces, aft of and adjacent to the screw.

8. A screw-propeller in combination with a bracket provided with guide-blades which surround the screw aft of its longitudinal center.

In testimony whereof I affix my signature in presence of two witnesses.

ISAAC MCKIM CHASE.

Witnesses:

D. C. REINOHL, D. WEIMnR REINOHL.

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