IMPROVEMENTS IN STEERING GEAR
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said John Granroth at the Office
of the Commissioners of Patents on the 31st August 1882.
JOHN GRANROTH, of Greenock in the County of Renfrew, North Britain,
Engineer, "IMPROVEMENTS IN STEERING GEAR
"
This Invention has for its object to simplify and otherwise improve the
constructive details of steering gear.
In carrying out the Invention the rudder head is formed with two diametrically
opposite radial slots and these slots are fitted with sliding blocks bored to receive
vertical pins which project down into them from two screw-and-feather blocks
above. A horizontal shaft carried in suitable bearings at or near its ends is placed
in a fore-and-aft position directly over and near to the rudder head and this
shaft has the ordinary steering wheel fixed on its fore end. In one modification
the horizontal shaft has a right-hand screw thread formed on one half of it and a
left-hand screw thread on the other half. The two screw-and-feather blocks are
formed with parts having internal screw threads for the right-hand and left-hand
screw threads of the horizontal shaft to work in, the internally screwed part being
formed at the fore end of one block and at the after end of the other block; and
each block is formed with one or more longitudinal feathers and with lateral parts
having one or more longitudinal grooves arranged in such manner that when the
parts are put together the feathers of one block engage in the grooves of the other
block the two blocks being thereby made to guide and steady each other. The
screw-and-feather blocks hold or have attached to them the pins hereinbefore
referred to as projecting down into the blocks in the radial slots of the rudder
head; and when the horizontal shaft is turned the action of the screws makes one
block move forwards and the other backwards and these reversed motions being
Di Q71

page_text: communicated by the vertical pins to opposite sides of the rudder head cause the
turning of the rudder to port or starboard as required.
In another modification right-hand and left-hand screw grooves are both formed
from end to end of the working part of the horizontal shaft, the two grooves
crossing each other. The screw-and-feather blocks are made with semicylindrical
cavities which are formed with internal screw threads that of one block being right-
handed and that of the other left-handed; and the blocks are connected and guided
by grooved parts and feathers as in the first modification.
Instead of the grooved parts being formed on the blocks they may be on separate
pieces fixed to the framing and arranged to fit upon feathers or equivalent
longitudinal flanges or ribs on the blocks.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Granroth in the Great Seal Patent Office on the 27th February
1883.
JOHN GRANROTH, of Greenock, in the County of Renfrew, North Britain
Engineer, "IMPROVEMENTS IN STEERING GEAR
"
My said Invention has for its object to simplify and otherwise improve the
constructive details of steering gear.
In carrying out my Invention the rudder head is formed with two diametrically
opposite radial slots, and these slots are fitted with sliding blocks bored to receive
vertical pins which project down into them from two screw-and-feather blocks
above. A horizontal shaft carried in suitable bearings at or near its ends is placed
in a fore-and-aft position directly over and near to the rudder head, and this shaft
has the ordinary steering wheel fixed on its fore end. In some modifications the
horizontal shaft has a right-hand screw thread formed on one half of it and a left-
hand screw thread on the other half. The two screw-and-feather blocks are formed
with parts having internal screw threads for the right-hand and left-hand screw
threads of the horizontal shaft to work in, the internally screwed part being formed
at the fore end of one block and at the after end of the other block; and each block
is formed with one or more longitudinal feathers and with lateral parts having one
or more longitudinal grooves arranged in such manner that when the parts are put
together the feathers of one block engage in the grooves of the other block, the two
blocks being thereby made to guide and steady each other. The screw-and-feather
blocks hold or have attached to them the pins herein before referred to as projecting
down into the blocks in the radial slots of the rudder head; and when the horizontal
shaft is turned the action of the screws makes one screw-and-feather block move
forwards and the other backwards, and these reversed motions being communicated
by the pins to opposite sides of the rudder head cause the turning of the rudder to
port or starboard as required.
In other modifications right-hand and left-hand screw grooves are both formed
from end to end of the working part of the horizontal shaft, the two grooves
crossing each other. The screw-and-feather blocks are made with semicylindrical
cavities which are formed with internal screw threads, that of one block being
right-handed and that of the other left-handed; and the blocks are connected and
guided by grooved parts and feathers as in the other modifications.
Instead of the grooved parts being formed on the blocks they may be on separate
pieces fixed to the framing and arranged to fit upon feathers or equivalent
longitudinal flanges or ribs on the blocks.
And in order that my said Invention and the manner of performing the same
may be properly understood I hereunto append three sheets of explanatory
drawings to be hereinafter referred to and representing various modifications of
my improved screw-and-feather steering gear.
Figure 1, on sheet 1, of the accompanying drawings is a plan and figure, 2, is a
corresponding side elevation of one modification of my improved steering gear;
and figures, 3, 4, and 5, are sectional end elevations showing slight variations, that
of figure, 4, being the same as that shewn in figures, 1, and 2. Figures, 6, 7, and 8,
on sheet 2, show a second modification and figures, 9, and 10, two variations
thereof. Figures 11, 12, and 13, show a third modification and figures, 14, and 15,
two variations thereof. Figures, 16, 17, and 18, on sheet 3, show a fourth modi-
fication and figure, 19, a variation thereof. Figures, 20, and 21, show a fifth
modification which may also be varied in a similar manner to some of the other
modifications. In these drawings the same reference numerals are used to mark
the same or like parts wherever they are repeated.
In the first modification, shown in figures 1, 2, and 4, the rudder head, 22, is
made with two short oppositely extending arms having radial slots, 23, formed in
them, and these slots are fitted with sliding blocks, 24, bored to receive vertical

page_text: pins, 25, which project down into them from two screw-and-feather blocks, 26,
above. A horizontal shaft, 27, having journals, 28, at or near its ends and carried
in suitable bearings in framing standards which are not shown, is placed in a fore-
and-aft position directly over and near to the rudder head, 22; and this shaft, 27,
may have the ordinary steering wheel fixed on its fore end, or it may be connected
in any convenient way to another shaft having a steering wheel on it, or it may be
arranged to be driven by means of steam or hydraulic or other suitable machinery.
This horizontal or main shaft, 27, has one half of its acting part made with one or
more right-hand screw threads and the other half with one or more left-hand screw
threads. The two screw-and-feather blocks, 26, are made with parts towards
opposite ends which are formed with internal screw threads to engage with the
screw threads of the shaft, 27, one block 26 engaging with the right-hand thread
or threads and the other block, 26, engaging with the left-hand thread or threads
of the shaft, 27. The vertical dotted lines, 29, in figures 1 and 2, indicate the
inner ends of the internally screwed boss-like parts of the blocks, 26.
The two
blocks, 26, are fitted to each other with grooves and feathers which bind them
together laterally whilst allowing them to move longitudinally upon or relatively
to each other. In the variation shown in figures 1, 2, and 4, each block, 26, is
made with a projecting feather or rib, 30, having parts at right angles to each
other, and each block is also formed with a rib or lateral extension, 31, which is
grooved internally so as to enclose the feather, 30, of the other block. The blocks,
26, are also formed with lugs or projections, 32, which are bored to receive the
pins, 25, these pins being entered down through them into the blocks, 24, which
are fitted to slide in the radial slots, 23, of the rudder head, 22. In the variations
shown in figures, 3, and 5, the feathers, 30, and grooved parts, 31, of the blocks, 26,
are arranged a little differently from those shown in figure, 4, they are however in
all three variations formed towards the sides of the blocks.
In figures 1, and 2, the rudder head, 22, is shown in its middle position; but in
the corresponding views of the other modifications the rudder head, 22, is shown
as turned to some extent to one or other side of its middle position, and the screw-
and-feather blocks, 26, which are in their middle positions in figures 1 and 2, are
in the other figures shown in other positions corresponding with the positions of
the rudder head, 22.
In the second modification shown in figures, 6, 7, and 8, the parts are very
similar to those of the first modification; but the feathers, 30, and grooved
parts, 31, of the screw-and-feather blocks, 26, are formed at the top and bottom
thereof, and one block, 26, is made with two feathers, 30, the other block being
made with two grooved parts, 31, to engage therewith. In the variation shown in
figure, 9, each block, 26, is made with a feather, 30, and with a grooved part, 31,
to engage with the feather, 30, of the other block. In the variation shown in
figure, 10, there is a single grooved part, 31, on one block, 26, engaging with a
single feather, 30, on the other block.
In the third modification, shown in figures, 11, 12, and 13, each screw-and-
feather block, 26, is made with a projecting feathered part, 30, at its bottom, the
projecting parts being made with flat bottom surfaces to slide upon a stationary
longitudinal guide bar, 33, which is fixed at its ends to the framing standards, and
which is formed with lateral overlapping edges, 34, to enclose the feathers, 30.
This guide bar, 33, serves to bind the blocks, 26, together and also to counteract
any lateral tilting or rocking of those blocks. In the variation shown in figure, 14,
the fixed guide bar, 33, 34, applied below is combined with a feather, 30, and
grooved part, 31, applied at the top of the blocks, 26, and in the variation shown
in figure, 15, fixed guide bars, 33, 34, are applied to the blocks, 26, both above
and below.
In the fourth modification, as shown in figures, 16, 17, and, 18, the arrangement
is similar to the variation of the second modification shown in figure, 9, the form
of the screw-and-feather blocks, 26, being varied in a manner which can be easily
understood from the drawings. In the variation shown in figure, 19, each screw-

page_text: and-feather block, 26, is made with two feathers, 30, at right angles to each
other, and with two grooved parts, 31, to engage on the feathers, 30, of the other
block.
In the fifth modification shown in figures, 20, and 21, instead of the right-hand
and left-band screw threads being formed at different parts of the main shaft, 27,
they are both formed from end to end of the acting part, and across each other;
and the screw-and-feather blocks, 26, are made with internally screwed semi-
cylindrical cavities to engage one on each side of the shaft, 27. With this
arrangement although one half only of the screw shaft, 27, acts on each block, 26,
this is more than compensated for by the increased length of which the internally
screwed part can be made. With the modification of the shaft, 27, shown in
figures, 20, and 21, the forms and arrangement of the feathers, 30, and grooved
parts, 31, of the blocks, 26, may be varied like those of the other modifications;
but it is unnecessary to give a series of sectional end elevations to show such
variations as they would be like many of the figures which are given. Thus an
end elevation corresponding to figures, 20, and 21, would be almost the same as
figure, 9. The fixed guide bars, 33, 34, may of course be used with suitable
variations of the fifth modification.
It will be obvious that the connections between the screw-and-feather blocks, 26,
and the rudder head, 22, may be modified in various ways. Thus instead of the
plain pins, 25, dropped down through the lugs, 32, into holes in the blocks, 24,
which slide in the radial slots, 23, of the rudder head, 22, as shown in figures 1
to 9, the lower blocks, 24, may be formed as shown in figure, 10, with pins
projecting up from them through the eyes in the lugs, 32. After being passed up
from below, cap nuts, 35, are screwed upon the upper ends of the pins washers, 36,
being first put on. According to another plan shown at the right-hand side of
figure, 14, a washer, 36, may be put over the end of the pin after the latter has
been entered up from below and then a horizontal cotter or a split pin may be
passed through the pin above the washer; or as shown at the left-hand side of
figure, 14, the end of the pin may be grooved and a horse-shoe washer, 37, may be
made to engage with the groove and be secured by a vertical pin, 38.
Having thus particularly described my said Invention and the manner of
performing the same I have to state that I do not restrict myself to the precise
details herein described or delineated but that what I believe to be novel and
original and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent is :-
The improved steering gear, in which a pair of screw-and-feather blocks moved
in opposite longitudinal directions by right-hand and left-hand screw threads on
the same longitudinal shaft, act directly by vertical pins on blocks sliding in radial
slots formed in the rudder head the said screw-and-feather blocks being connected
together by feathers and grooved parts on each other or partly on fixed guide bars
substantially as hereinbefore described.
In Witness whereof, I, the said John Granroth, have hereunto set my hand
and seal this twenty-sixth day of February in the year of our Lord One
thaugend night hondoad and right thena
Witness
EDMUND HUNT
Patent Agent
Glasgow
JOHN GRANROTH (L.B.)