US51446A - Improvement in the construction of screw-propeller blades - Google Patents

Description

UNITED STATES PATENT OFFICE,

CHARLES C. GATES, OF ALBANY, NEW YORK.

IMPROVEMENT IN THE CONSTRUCTION 0F SCREW-PROPELLER BLADES.

Specification forming part of Letters Patent No. 51,4146, dated December 12, 1865.

Yo all 'whom tt may concern:

Be it known that I, CHARLES C. GA'rEs, of the city and county of Albany, in the State of New York, have invented a new and improved method of' Forlning Propeller-Blades; and I do hereby decla-re the following to be a full and exact description of the saine, reference being had to the annexed drawings, making a part of the specification, in which- Figure 1 is the formula for the construction ofthe blades, and Fig. 2 a plan of the curves on the acting-surface of the blades, and Fig. 3, a perspective side elevation of one of the blades.

The nature of my illventioll relates to the lnanller of' constructing propeller-blades, so as ill their revolutions to give'the water a celltrifugal actioll on the blades7 acting-surface, tllereby receiving all increasing impetus, vet confining the water within the outer curve an d finally throwing the water ofi' directly aft, by lnealls of curved lilies as combined with the various allgles of the staves with the lille of shaft, said curved lines giving the form ofeach particular stave, they being of various widths, and also as to tlleir various thicknesses and taper or wedging forms. The acting-surface of' the blades (at the hub only) have the f'ornl ot' a helix or lille of a screw, alld at the outer curve, only, they lie ill a plane, the area of the blades7 surface conforming to the various curves alld tapering thicknesses ofthe staves and their relative angles.

The following description will enable others skilled ill the art to make and use llly invention.

The blades are forlned, as in the ordinary lnanller of construction, by gluing each stave together relatively to its curves and the required pitch or angle, Fig. l being a formula as it lies wholly ill a plane, it being given for the purpose of' showing the lnanner of' producing the forms of staves, they each bein g of various lengths and thicknesses. The line of' clearance being giving fore and aft, I then draw a straght lille ofthe required angle with line of shaft alld respectively to the wheels dimensions to O, it being the extreme of the blade aft, as shown in Fig. l. Then dividing said line equally into any given number of spaces, I also divide on the center line the hubs length, which is about half the wheels cleavance (fore and aft) into the same given number of spaces, the hub being thrown forward for the purpose of throwing a majority of the staves at a greater angle aft with line of shaft. I then draw straight lines from the division points l 2 3 4, &c., at the hub-center, through their respective divisions l 2 3 4, etc., on lille A b O to the outer curves, A d O, of' blade, said curve being subject to alterations so as to conform with lille A b O. Fig.2 is to show the acting-surface of' the blades, also showing the line A b O to be a curved one, and also equally divided with the saine given number of spaces l 2 3 4, Sac., of' formula, and with their respective radii equal with those of the formula. I then draw f'ronl the hubs centerradiating lilies, as shown in red ink, through the division-points to the outer curve ofblade; and then from the intersecting-points l 2 3 4, &c on t-he curved lineA b C, I. set back about two-thirds of each division for the purpose of forming curved lines, (said curves lgiving the form of each particular stave.) Then iroln the radiating lines at the outer curve, A d O, I draw concave lines, intersecting them at the two-third division of each space on lille A b O, then receding until they gradually assume convex lines and tangenling the radiating lilies from the hub center. The concavity or dishing-surface of' the blade is produced by said curved lilies alld gradually flattening at all illereased radius on lille A b O until itconforlns with a straightline at O. The lapping surface for gluing the staves together are relative to the required thickness for strength and the angle ofblades. After the blades beingformed I then cut away from A and H to the hubs surface several ot' the outer staves for the purpose of lessenillg the vacuuln and drag on the back of' the blades, the back ofthe blades then being chanlfered to an edge to facilitate its passage through the water.

I anl aware that lines of a plane have been used by others, also the increasing edges of blades, therefore, I do not claim, broadly and irrespective of construction, such devices; but

What I do claim, and desire to secure by Letters Patent, is

The manner of forming the blades by their irregular curves and Widths and unequal thicknesses of staves, as combined and arranged as specified, and for the purpose set fortll.

CHARLES C. GATES.

Witnesses:

S. M. CLARK, F. E. SPINNER.

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