Improvements in and relating to Ships' Propellers.
Year: 1891

page_text: Date of Application, 27th June, 1891
Complete Specification Left, 26th Mar., 1892-Accented, 30th Apr., 1892
PROVISIONAL SPECIFICATION,
Improvements in and relating to Ships' Propellers.
I, ALEXANDER BURNS of Claremont House, Uddingston, in the County of
Lanark, North Britain, Clothier, do hereby declare the nature of this invention to
be as follows:-
My invention relates to propellors wherein flat discs, boards or other surfaces
are thrust direct against the water in the line of motion; and consists of new or
improved constructions or arrangements of parts thereof, designed for effecting
greater efficiency and economy in action than those heretofore.
As constructed according to my invention the propellor consists of a set of two
or three metal sheets or wooden boards hinged together, so as when shut to give
little resistance to being drawn through the water, but when expanded to give a
great resistance. The said propellors are mounted on rods working through the
ships stern in pairs, one on each side equidistant from the centre line. There are
altogether six propellors and rods; the three pairs being driven through their
respective connecting rods from a transverse motive power shaft having three
cranks set at equal angles. Otherwise, each pair of propellor rods may be con-
nected to one piston rod working in a motive power cylinder direct. Each pro
pellor may have a setting arrangement consisting of a circular frame rigidly
horizontally fixed on rod, over which the edge of blades turn, and on which may
be put or set projections or stops against which the blades set, and are thereby
retained.
Dated this 28th day of June 1891
D. F. MASON,
Glasgow, Patent Agent.
COMPLETE SPECIFICATION.
Improvements in and relating to Ships' Propellers.
1, ALEXANDER BURNS, of Claremont House, Uddingston, in the County of
Lanark, North Britain, Clothier, 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:—
My invention relates to propellers wherein flat discs, boards or other surfaces
are thrust direct against the water in the line of motion, or drawn against it for going
backwards; and consists of new or improved arrangements and constructions of
parts thereof designed for effecting greater efficiency and economy in action than
heretofore.
And in order that the invention may be properly understood have appended a
sheet of explanatory drawings whereon
Fig. 1 is a plan of the arrangement of parts according to my said invention.
Fig. 2 is a back elevation of the propeller, and Fig. 3 is a plan thereof and
its rod.
Fig. 4 is a diagram of cranks and connecting rods.
As constructed according to my said invention the propeller consists of a set of
two metal blades or sheets 4, 4¹ hinged by bolts 5 (Figs. 2 & 3) to lugs 6 on hollow
spindle 7 which has two semicircular ribs 8 inside which the outer edges of
blades 4, 4' turn. A reciprocating hollow rod 9 is fixed into the hollow spindle 7
which rod passes through stuffing box in ship's stern quarters.
The outer edges of blades 4, 4' are retained by the stops or catches 10 on end of

page_text: levers 11 hinged at 12 to ribs 8, when the said stops 10 are in over ribs 8 as shewn ;
the blades not being able to pass said stops 10 until they are withdrawn. For the
ship going forwards in direction as indicated by arrow 13, the stops 10 are in on
front face of blades as shewn by blade 41 in Fig. 3, so that when the propeller is
thrust backwards the blades are stopped at or about right angles to motion line,
and thus offer resistance to the water.
When the propeller is drawn inwards to the ship, the blades fold backwards on
to a pin 14 which may have a spring if desired, to keep the blades slightly angled
so as to open freely when the propeller is again thrust backwards.
The blades 4, 4 have a triangular cutwater (not shown) fixed. perpendicularly in
front of centre of propeller, which cutwater helps to divert front pressure from
propeller when recovering its stroke or preferably the blades 4, 4' may be made
so as to have a part c on opposite side of hinge to main blades 4, 4', thus giving a
greater bearing surface when open, and when shut allowing the water to pass
freely between the blades and thus prevent suction and front pressure. To cause
the ship to move backwards the stops 10 are withdrawn before the propeller is
thrust outwards so that the blades fold forwards to pins or springs 15 when the
propeller is thrust out. The stops 10 are then returned to position shewn at
Fig. 3, so that when the propeller is again drawn inwards, the edges of blades
can't pass stops 10 thus causing the blades to effect a dragging action of the
ship backwards.
The catch lever 11 is operated by a rod 16 which slides inside the hollow pro-
peller rod 9. The rod 16 has two pins 17, 18, fixed therein, one 18 inside ship,
and one 17 outside ship, projecting through small slots in hollow rod 9. The pin 17
works in small slots in front end of levers 11, so that when the rod 16 is drawn
forward by the pin 18, inside ship, the catches 10 are pushed inwards.
When the
rod 16 is pushed outwards the catches 10 are withdrawn from sides of ribs 8. The
rod 16 reciprocates inside and along with propeller rod 9, and is fitted watertight
therein by a stufting box between the pins 17 and 18. The hollow propeller rods 9
reciprocate through stuffing boxes in ship's shell 20 at stern quarters as indicated
at Fig. 1; the front ends of said rods being fitted with a slipper sliding in guides
at point 26, and fitted to connecting rods 21 and cranks 22 all in usual way.
There are altogether six propellers and rods, three on each side the centre line
of keel, and working in pairs as shewn at Fig. 1; being driven through their
respective connecting rods from transverse motive power shaft 23 which has two
sets of three cranks 22 set at equal angles as shewn at Fig. 4. Although shewn
all of same length at Fig. 1, the rods 9 are preferably made of different lengths,
the outer rods being of such length as to suit the ship's lines.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, 1 declare that what 1
claim is,
1st. The arrangement and construction of parts of ships propellers substantially
as set forth and shewn.
2nd. The arrangement and combination of rods 9 & 16, levers 11, and ribs, 8, as
and for the purposes described and shewn.
Dated this 25th day of March 1892.
DAVID F. MASON,
Patent Agent.