IMPROVE- MENTS IN STEERING GEAR
Year: 1882

page_text: LETTERS PATENT to Thomas Archer junior of Dunston Engine Works
Dunston in the County of Durham, Engineer for an Invention of IMPROVE-
MENTS IN STEERING GEAR
PROVISIONAL SPECIFICATION left by the said Thomas Archer, junior, at
the Office of the Commissioners of Patents on the 2nd February 1882.
THOMAS ARCHER junior, of Dunston Engine Works, Dunston in the County of
Durham, Engineer IMPROVEMENTS IN STEERING GEAR
My Invention consists in the application to steering gear for ships or steamers of
arrangements of what is called differential gear combined with clutch arrangements,
whereby when the differential gear is engaged firstly a powerful leverage is brought
to bear upon the rudder chains and secondly the resulting strain due to the action
of the water on the rudder after it is placed in the desired position is so taken up
in the differential gear itself as to impart little or no strain to the steering wheel
I thus attain increased facility in steering and practicably an automatic holding of
the wheel in any position in which it may have been placed.
The gear which I prefer to employ for the purpose consists of a toothed wheel
actuated by an eccentric wheel within it in such a manner as that it takes the
motion due to the said eccentric in all directions except in the direction of the
revolution of the said eccentric that is to say it is capable of moving vertically or
horizontally and at every angle between in the direction of and according to the
position of the long axis of the eccentric but it is preverted from rotating
by means of certain projections gearing into slots as is well understood.-This
toothed wheel at one part, namely in the direction of the long axis of the
eccentric before described gears into an internally toothed wheel and the part of
this last mentioned wheel in gear changes as the position of the long axis of the
eccentric changes.
The number of teeth in the internally toothed wheel I make different from the
number of teeth in the externally toothed wheel, and by reason of the difference in

page_text: this number of teeth the movement of the last mentioned wheel due to the eccentric,
altho' not itself a rotary movement yet imparts rotary movement to the internally
toothed wheel greater or less according to the difference of the number of the teeth
in each and this rotation is accomplished with a loverage inversely proportioned to
the difference in the number of the teeth as is well understood and the holding
power of the arrangement beyond the friction of the apparatus is proportioned to
the leverage. The clutches are of any convenient form arranged for the purpose of
throwing the differential gear into or out of gear as may be desired.
The clutches I have referred to may be of any convenient form and aro used
merely to throw the differential arrangement into or out of gear.
The steering gear according to my Invention may be operated either by hand or
by any description of mechanical power.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Archer, junior, in the Great Seal Patent Office on the
1st August 1882.
THOMAS ARCHER junior of Dunston Engine Works Dunston in the County of
Durham Engineer "IMPROVEMENTS IN STEERING GEAR"
My Invention consists in the application to steering gear for ships or steamers of
arrangements of what is called differential gear combined with clutch arrangements
whereby when the differential gear is engaged firstly a powerful leverage is brought
to bear upon the rudder chains and secondly the resulting strain due to the action
of the water on the rudder after it is placed in the desired position is so taken up
in the differential gear itself as to impart little or no strain to the steering wheel
I thus attain increased facility in steering and practically an automatic holding of
the wheel in any position in which it may have been placed The gear which I
prefer to employ for the purpose consists of a toothed wheol actuated by an
eccentric wheel within it in such a manner as that it takes the motion due to the
said eccentric in all directions except in the direction of revolution of the said
eccentric that is to say it is capable of moving vertically or horizontally and at
every angle between in the direction of and according to the position of the long
axis of the eccentric but it is prevented from rotating by means of certain pro-
jections gearing into slots as is well understood This toothed wheel at one part
namely in the direction of the long axis of the eccentric before described gears into
an internally toothed wheel and the part of this last mentioned wheel in gear
changes as the position of the long axis of the eccentric changes
The number of teeth in the internally toothed wheel I make different from the
number of teeth in the externally toothed wheel and by reason of the difference in
this number of teeth the movement of the last mentioned wheel duc to the eccentric
although not itself a rotary movement yet imparts rotary movement to the internally
toothed wheel greater or less according to the difference of number of the teeth in
each and this rotation is accomplished with a leverage inversely proportioned to
the difference in the number of the teeth as is well understood and the holding
power of the arrangement beyond the friction of the apparatus is proportioned to
the leverage The clutches are of any convenient form arranged for the purpose
of throwing the differential gear into or out of gear as may be desired
The clutches I have referred to may be of any convenient form and are used
merely to throw the differential arrangement into or out of gear
The steering gear according to my Invention may be operated either by hand or
by any description of mechanical power
Having thus described the nature of my Invention I will proceed more par-
ticularly to describe the manner in which the same is operated reference being
made to the Drawings bereto attached that is to say. In the Drawings similar
parts are referred to by the same letters A Figs 1 and 2 is the steering wheel
used for operating the gear by hand B is the steering chain passing over a chain
wheel C so as that the alternate links engage in corresponding elevations and
depressions in the grove of the wheel to prevent slipping when power is transmitted
The chain wheel has a rim D with internal teeth and is made free to turn on its
axis Within this rim is placed a second toothed wheel with external teeth of like
pitch with the teeth of the wheel first described but with a smaller number of
teeth the diameter of this second wheel being such as that when the teeth are
engaged on one side of the external wheel they are disengaged on the opposite side
but never on both sides together These wheels are shown more in detail in Figs 3

page_text: and 4 The internal wheel is prevented from revolving on its axis by means of
pius attached to it working in fixed slots or by means of a rod attached to it which
rod may be guided in the standards or in any other convenient way the pins and
slots or the rod are so arranged as merely to prevent rotation but to give freedom
of movement in the direction of the movement of the strap of an ordinary eccentric
The inner wheel is bored out in its centre so as to fit over an eccentric and this
eccentric is keyed to the first motion shaft and steering wheel A The eccentric is
shewn in Fig 5 By the movement of the first motion shaft and its eccentric the
inner wheel is caused to alter its position and its teeth are then caused to engage
in different teeth of the internally toothed wheel which surrounds it and as the
number of teeth in the outer wheel is greater than the number of teeth in the inner
wheel the effect of one revolution of the eccentric is that the tooth most deeply
engaged is engaged with a different tooth in the external wheel to that with which
it was engaged before the revolution of the eccentric and consequently the outer
wheel makes part of a revolution in the opposite direct to that of the eccentric.—
This partial revolution represents the leverage of the arrangement which leverage
I make very considerable so as to both give a greater power of pull on the rudder
chains and to reduce the pull tending to run back the mechanism to a small pull-
When the pull is thus reduced to a point corresponding to or below the friction of
the apparatus the rudder becomes fixed in any position in which it may be placed
and the wheel need no longer be held or lashed in position It will be manifest
that the arrangement I have described is capable of being operated by hand or by
steam or by any transmission of other power
Having thus described the nature of my Invention and the mode of operating the
same I claim the method herein described and shown of operating steering gear or
any mere modification of the same
In witness whereof I the said Thomas Archer junior have hereunto set my
hand and seal the Twenty eighth day of July in the year of our Lord
1000
THOMAS ARCHER, JUN". (L.S.)
Witness to the signing hereof
H. J. W. SCAIFE
Clerk with Mess". Arnott & Swan
Solicitors
Newcastle upon Tyne.