Improved Means for Reversing or Varying the Pitch of Screw- propeller Blades.
Year: 1892

page_text: Date of Application, 23rd Mar., 1892
Complete Specification Left, 23rd Dec., 1892-Accepted, 11th Feb., 1893
PROVISIONAL SPECIFICATION.
Improved Means for Reversing or Varying the Pitch of Screw-
propeller Blades.
We, WILLIAM DENT PRIESTMAN and SAMUEL PRIESTMAN, Directors of
Priestman Brothers Limited, Holderness Foundry, in the Town and County of
Kingston-upon-Hull, Mechanical Engineers, and JAMES NICHOLSON, of Beeton
Street, in the same town, Foreman Patternmaker, do hereby declare the nature
of this invention to be as follows:-
This invention relates to screw-propellers constructed with blades pivotally
mounted in the propeller-boss in such a manner as to admit of the inclination of
the blades being reversed or varied, and consists in improved means whereby such
axial movement of the blades may be effected and their angular set or pitch
adjusted.
"
In applying our invention to a two-bladed propeller, each blade is formed with
a shank whereby it is mounted in the boss of the propeller. Each shank may be
cylindrical, conical or spheroidal, or may assume the form of two cones placed end
to end; the larger ends of the cones being either towards the centre or towards
the extremities of the shank. The face of each shank is provided with a central
stud, preferably in the form of a rectangular block, which engages in a slot
formed in a plate; the two plates, appertaining to the respective propeller-
blades, being linked to pins which project from opposite sides and from opposite
ends of a central plate, fork or bow. The central plate is provided with a spindle,
which extends through the centre of the screw-shaft and which is furnished with
means whereby the central plate may be moved a certain distance to and fro in an
axial direction. The spindle may also be extended in the opposite direction, and
be utilised as an additional guide for the central plate. As such motion takes
place, the links impart a rotative movement to the blades, which may thus be
set and held at any desired angle of inclination, or in the plane of their rotation;
thus causing the power to be applied in a forward or in a backward direction or
to be merely dissipated radially, the direction of rotation of the screw-shaft and
propeller meanwhile remaining constant.
In order to assist in supporting the blades in their bearings and in preserving
the accuracy of their alignment, we prefer to connect them by means of a central
spindle which may be secured in the shank of one blade and made to enter a hole,
bored for its reception, in the shank of the other blade. Or, whilst the spindle
projects from the face of one shank, a sleeve may project from that of the other;
the spindle entering and fitting the sleeve. In either case, the blade-bearings
afford each other mutual support against wrenching strains. The central plate is
slotted to permit the passage of the transverse spindle and sleeve extending between
the shank of the opposite blades. The same object is attained by forming the
central plate as a fork or bow.
Instead of employing a spindle arranged concentrically with the main shaft, for
the purpose of actuating the central plate as hereinbefore described, the appliances
for varying or reversing the angular position of the blades may be operated by
means of a sleeve or rods arranged externally to the screw-shaft or by causing the
stern-shaft itself to move longitudinally. With this object, the shaft may be
provided with collars enclosing between them a loose ring, which, by means of a
lever and worm-gear or by other suitable appliances, may be moved to and fro and
caused to impart a longitudinal movement to the shaft; a feather on the same
sliding in a feather-way in the coupling. Under such circumstances, the shaft
slides longitudinally in the propeller; and the appliances for varying or reversing

page_text: the angular position of the propeller-blades may, if necessary, be modified to permit
of this movement.
Dated this 17th day of March 1892.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improved Means for Reversing or Varving the Pitch of Screw-
propeller Blades.
We, WILLIAM DENT PRIESTMAN and SAMUEL PRIESTMAN, Directors of
Priestman Brothers Limited, of Holderness Foundry, in the Town and County of
Kingston-upon-Hull, Mechanical Engineers, and JAMES NICHOLSON, of Beeton
Street, in the same town, Foreman Patternmaker, 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:-
This invention relates to screw-propellers constructed with blades pivotally
mounted in the propeller-boss in such a manner as to admit of the inclination of
the blades being reversed or varied, and consists in improved means whereby
such axial movement of the blades may be effected and their angular set or "pitch'
adjusted.
The way in which we prefer to carry out our invention is illustrated in' the
accompanying drawings, whereof
Fig. 1 is a view partly in section and partly in side elevation showing the stern
of a vessel having a propeller furnished with our improved means for reversing 'or
varying the pitch of the propeller-blades.
Fig. 2 being a corresponding view, drawn to a smaller scale, illustrating'an
alternative form of actuating mechanism.
Figs. 3 and 4 are side and rear elevations respectively of the propeller-blades
mounted in the split propeller-boss.
Fig. 5 is a view partly in side elevation and partly in section on the line 5, 5' 'in
Fig. 4.
Fig. 6 is a rear elevation with the outer part of the propeller-boss removed.
Fig. 7 is a horizontal section on the line 7, 7 in Fig. 5.
Fig. 8 is a view partly in side elevation and partly in section showing a different
design.
Fig. 9 being a horizontal section on the line 9, 9 in Fig. 8.
Figs. 10 and 11 are views corresponding with Fig. 9, but representing the parts
in other positions.
In applying our invention to a two-bladed propeller, each of the blades A and A'
is formed with a shank C or C', whereby it is mounted in the boss D D' of the
propeller. The parts D and D₁ of the propeller-boss are bolted' together and to
a flange on the end of the propeller-shaft H by bolts d. Each of the shanks C
and C may be cylindrical, conical or spheroidal, or may assume the form of two
cones placed end to end. In the latter case, the larger ends of the cones may lie
either towards the centre of the shank, as shown in Figs. 5 and 6, or towards its
extremities, as illustrated in Fig. 8. The face of each shank is provided with a
central stud, preferably in the form of a rectangular block, which engages in a slot
formed in a plate E or E'; the two plates E and E' engaging with pins projecting
from opposite sides of a central frame F. One of these pins E2 is represented by
a full circle and the other pin by a dotted circle in Fig. 7. Instead of this central
frame, a fork or bow may be employed. The stud or rectangular block C³ pertaining
to the shank C¹ is exposed in Fig. 7. The frame F is provided with a spindle F',
which extends through the centre of the screw-shaft H. The spindle F is keyed
to a collar F on the hollow part of the shaft H; the key passing through slots in
the shaft. By means of a lever K, the collar is moved to and fro on the shaft,

page_text: thus causing the central frame F to move to and fro a corresponding distance in
an axial direction; the said lever engaging with a quadrant K', in the usual
way, and being arranged in such a manner as to permit of the collar rotating with
the shaft. The spindle F¹ may also be extended in the opposite direction, and be
utilized as an additional guide for the frame F. The extension F2 of the spindle
works in a hole in the part D'. When the spindle F is moved in an axial direction,
the plates E and E' slide on and turn the rectangular blocks, and thereby impart
a rotative movement to the blades A and A', which may in this manner be set
and held at any desired angle of inclination, or in the plane of their rotation ;
thus causing the power to be applied in a forward or in a backward direction, or to
be merely dissipated radially, the direction of rotation of the screw-shaft H and
propeller A A meanwhile remaining constant.
In Fig. 2, the lever G for actuating the central frame F is placed between the
rudder L and the propeller A A¹. The spindle F1 then projects from the part D¹
of the propeller-boss in order to enable the lever G to engage with a collar furnished
with trunnions and mounted on the end of the spindle.
In order to assist in supporting the blades A and A' in their bearings and in
preserving the accuracy of their alignment, we prefer to connect them by means of
a central spindle A2, which may be secured in the shank of one blade (A) and
made to enter a hole, bored for its reception, in the shank of the other blade (A').
Or, whilst the spindle (A2) projects from the face of one shank (C), a sleeve (A³)
may project from that of the other (C'); the spindle A2 entering and fitting the
sleeve A³. In either case, the blade-bearings afford each other mutual support
against wrenching strains. The transverse spindle A² and sleeve A³ pass through
the frame F.
In Figs. 8 to 11, instead of a frame, fork or bow, a cross-head F³ is shown;
this cross-head working in and being guided by grooves formed in the boss D D¹.
The pins for effecting communication between the slotted plates E and E¹, which work
on the blocks C2 and C³, and the cross-head F³ project from the said plates and
engage in holes in the cross-head. In these figures, the cross-head F3 is shown on a
spindle F adapted for being actuated by a lever G, as indicated in Fig. 2; but it
may be on a spindle actuated by a lever K, as indicated in Fig. 1.
Instead of employing a spindle arranged concentrically with the main shaft, for
the purpose of actuating the central plate or frame as herein before described, the
appliances for varying or reversing the angular position of the blades may be
operated by means of a sleeve, or of rods, arranged externally to the screw-shaft,
or by causing the stem-shaft itself to move longitudinally. With this object, the
shaft may be provided with collars enclosing between them a loose ring, which,
by means of a lever and worm-gear or by other suitable appliances, may be moved
to and fro and caused to impart a longitudinal movement to the shaft; a feather
on the same sliding in a feather-way in the coupling. Under such circumstances,
the shaft slides longitudinally in the propeller; and the appliances for varying or
reversing the angular position of the propeller-blades may, if necessary, be modified
to permit of this movement.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, we claim
1. The improved means for reversing, or varying the pitch of, screw-propeller
blades, arranged and operating substantially as described with reference to the
accompanying drawings.
2. The improved means for reversing, or varying the pitch of screw-propeller
blades, comprising a sliding frame, fork, bow or cross-head, such as For F³,
blocks on the shanks C and C¹ of the propeller-blades, and plates E and Ei
engaging with the frame and with the blocks, substantially as herein described.
3. In a screw-propeller, the herein-described means for reversing, or varying
the pitch of, the movable blades A and A¹, comprising a sliding frame, fork, bow
or cross-head, such as For F³, between the blades, two slotted plates E and E'

page_text: engaging with the sliding frame and with blocks on the shanks of the blades, and
mechanism for causing the frame to slide for the purpose of moving the plates and
thereby turning the blades so as to vary, or reverse, their pitch.
4. In a screw-propeller, mounting the movable blades A and A' in recessed
bearings formed in the contiguous faces of the parts D and D' of the propeller-boss,
such boss being secured to a flange h on the end of the propeller-shaft H, and
turning the blades by means of a sliding frame, fork, bow or cross-head, F or F³,
two slotted plates E and E', blocks on the shanks of the blades wherewith the
plates engage, and mechanism for causing the frame to slide, substantially as herein
described.
5. In a screw-propeller having blades mounted pivotally in the propeller-boss,
the employment of a pin on the shank of one blade fitting in a hole in the shank of
the other blade for the purpose of enabling the blades to mutually support one
another substantially as herein described.
Dated the 23rd day of December 1892.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.