Improvements in Propellers.
Year: 1895

page_text: Date of Application, 29th Oct., 1895-Accepted, 14th Dec., 1895
COMPLETE SPECIFICATION.
Improvements in Propellers.
We, ORESTES PAGAN, of 1108 Parrish Street, Mechanical Engineer, JOSIAII
K. BOUGHER, of 1823 North Broad Street, Merchant, and HOWARD EVANS, of
2033 Locust Street, Merchant, all of the City and County of Philadelphia, State
of Pennsylvania, one of the United States of America, do hereby declare the nature
of this invention, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The object of this invention is to so construct a screw propeller that it will draw
the full supply of water necessary for its area of blade surface, only from the
direction in which the vessel is advancing. This object is attained according to this
invention by making a hollow skeleton hub so as to destroy the vacuum that is
formed in propellers now in general use.
In the accompanying drawings
Figure 1 is a view of the improved propeller with the hub in section.
Figure 2 is a side view partly in section.
Figure 3 is a detached view of one of the hub sections.
Figure 4 is a side view shewing means for adjusting the blades of the propeller.
Figure 5 is a view similar to Figure 4, with the exception that the blades are
adjusted at a different angle.
Figure 6 is a section on the line 6-6, Figure 4.
Figure 7 is a detached view of one of the blades.
Figure 8 is a view of a modification.
Figure 9 is a view shewing one method of clamping the blade in the adjusted
position.
Referring, in the first instance, to Figures 1, 2 and 3, A are the blades, four in
the present instance, being shewn but we are not limited to that number. Each
blade is mounted on a bolt C, these bolts pass through the two heads B1, B2, of the
propeller hub B.
The blades are prevented from turning on the bolts by lugs b, shewn clearly in
Figures 2 and 3, which enter cavities in the blades; but other means of locking
the blades to the hub sections may be used without departing from this invention.
The hub is made hollow as shewn and the section B2 has a large central
opening for the free escape of water. Channels 62 are also formed between the
blades at the hub so as to allow for the free passage of water into, and through, the
hub, thus destroying the vacuum usually formed in propellers having solid hubs.
The section B of the hub is shaped to receive the end of the propeller shaft D
which terminates in this section, thus leaving the body of the hub open for the free
passage of water.
It will be understood that in some instances the hub and blades may be cast in a
single piece, providing the hub is open at the centre in line with the blades and has
an outlet at the rear for the free escape of water.
In Figures 1, 2 and 3, we have shewn a propeller with fixed blades, while in
Figures 4 to 9 inclusive, we have illustrated a propeller having adjustable blades,
so that the blades can be set at different angles.
The base section A¹ of each blade has a passage a for a bolt C, the passage being
of such a width that the blades can be turned to the two extreme points, and
passing through each side of the base portion are set screws a', upon adjusting
which the blades can be locked at any desired pitch. In the present instance the
screws bear upon the bolts, as clearly shown in Figure 6.
We have shewn round bolts in Figure 6, but square bolts may be used as shown
in Figure 8

page_text: The hub section has curved sockets e to which are adapted the curved bases of
the blades so that when the parts are adjusted a neat fit is insured.
In Figure 9 we have shown a construction in which the set screws are dispensed
with, and in which the bolt C has a collar c which rests against a shoulder a² in the
base section of the blade, so that when the blade is adjusted to the proper angle it
is held in position by turning the nut c' on the bolt, drawing the collar hard against
the shoulder a2, after which the nnt c² can be tightened.
By making the propeller with independent blades any one of the blades can be
readily replaced, or can be removed, repaired, and readjusted, in position, and by
securing the hub section B only to the shaft the blades can be readily removed
without disturbing this hub section.
By the construction shown we are enabled to make a propeller with two or more
blades that will not churn the water within its disc as the water is free to escape
through the hub and destroy the vacuum.
As the propeller entirely frees itself from water it does not carry a mass of
water around within its disc, thus decreasing the liability of breakage.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
1. The combination in a propeller, of a hollow hub open at the rear, blades
projecting from the said hub and passages in the hub between the blades, the said
passages communicating with the opening at the rear, substantially as hereinbefore
described.
2. The combination in a propeller, of the independent blades, means for
adjusting the blades, and a hollow hub having passages between the blades
communicating with the central opening, substantially as herein before described.
3. The combination of the blades having base sections, hub sections B and B2
and bolts passing through the base sections of the blades and through the hub
section, the structure forming a passage at the centre of the propeller for the free
escape of water, substantially as herein before described.
4. The combination in a propeller, of the skeleton hub open at the rear, blades
projecting from the said hub, openings in the hub between the blades, the said
openings communicating with the open centre, and a propeller shaft stopping short
of the centre of the blades so as to allow for the free passage of water to the
centre through the openings between the blades, substantially as herein before
described.
5. The combination of the independent blades, each having a perforated base
section, hub sections 13 and 3, the hub section Bi formed to receive the propeller
shaft, the section B having a central opening for the escape of water, with bolts
passing through the said sections and through the base of each blade, substantially
as herein before described.
6. The combination of the sections B and B of the hub, the shaft secured to
one section, curved sockets on the sections, blades having bases adapted to the said
sockets, openings in each base, bolts adapted to the openings and to the hub
sections and set screws for locking the blades, substantially as herein before
described.
7. The combination in a propeller, of the hub, the adjustable blades, each blade
having an opening in its base, a shoulder a' on the blade, a confining bolt C having
a collar c bearing against the shoulder whereby the blade is secured to the hub,
substantially as hereinbefore described.
Dated this 29th day of October 1895.
JOHNSONS & WILLCOX,
Agents.