Improvements in or relating to Driving Gear for Autocars and other Machinery.
Year: 1899

page_text: Date of Application, 1st Aug., 1899
Complete Specification Left, 1st June, 1900-Accepted, 7th July, 1900
PROVISIONAL SPECIFICATION.
Improvements in or relating to Driving Gear for Autocars and
other Machinery.
We, HENRY THOMAS DAWSON and HENRY ALFRED DAWSON, both of Stour
Street, Canterbury, in the County of Kent, Engineers, do hereby declare the
nature of this invention to be as follows:-
:-
Our invention relates to driving gear for autocars and other machinery, and
has for its objects to provide, firstly, a compound clutch adapted to combine the
qualities of both a friction clutch and a positive clutch, and secondly, a locking
device to be used in conjunction with the said clutch and adapted to prevent
operation of another part or parts of the mechanism while the above mentioned
clutch is acting as a positive clutch.
The first part of our invention consists essentially in introducing, between
the parts of a friction clutch, one or more bolts which engage permanently in
apertures in one part of the clutch and are capable of being moved so as to
engage also in corresponding apertures in the other part of the said clutch,
when desired.
The second part of our invention consists essentially of a detent or the like
adapted to engage in a rack or the like on the gear changing or other mechanism
so as to prevent such mechanism being operated when the clutch is in positive
engagement, the said detent being actuated automatically by the mechanism
which operates the said clutch.
We will describe our improved clutch as applied to a case where rotary motion
is to be transmitted from a horizontal power shaft to a sleeve surrounding the
said shaft; though it will be readily understood that our invention is equally
applicable to other cases. The friction clutch may be of any suitable construc-
tion such as the well known cone clutch the inner part of which is, we will
suppose, rigid with the shaft, while the outer part of the clutch is rigid with the
sleeve. The webs of the inner and outer parts of the clutch are provided with
one or more corresponding apertures; and into a space arranged between
the said webs is introduced a loose, concentric disc carrying one or more trans-
verse bolts which project beyond both surfaces of the said disc. The disc is
impelled towards the web of the inner part of the clutch by a suitable spring or
springs, such as a series of expansion springs carried in recesses in the inner
face of the web of the outer part of the clutch. One or more longitudinal pins
or keys, each engage by one end with the said disc and by the other end with
a flanged collar sliding on the said sleeve. The sleeve and outer part of the
clutch are normally forced in the direction the inner part of the
clutch by an expansion spiral spring upon the shaft bearing against a fixed
collar or stop on the said shaft, in one direction, and the adjacent, flanged end
of the sleeve in the other direction. Normally, therefore, the lastly mentioned
spring tends to throw the friction clutch into action and the firstly mentioned
springs tend to throw the bolts forming the positive clutch, into action. These
tendencies are controlled by a bell cranked or other lever, one arm of which is
forked and is adapted to hear against the flanged sliding collar on the face
of

page_text: nearer the clutch, while the other arm is linked to a pedal lever of the second
order.
When the pedal lever is at its highest position the springs are allowed to
force the disc and bolts in the direction of the inner part of the clutch and when
the bolts coincide with the apertures therein the springs cause them to enter
such apertures and thus positively engage the clutch. By depressing the pedal
lever to an intermediate position, the upper end of the bell crank lever, acting
on the flange of the sliding collar, forces the said collar back against the
flanged end of the sleeve. The collar, acting through the keys, draws back
the disc against the web of the outer part of the clutch and so withdraws the
bolts from the web of the inner part of the clutch. The clutch then remains
engaged by friction only under the influence of the spring surrounding the
shaft. By further depressing the pedal lever the upper end of the bell crank
lever, acting on the flanged end of the sleeve through the sliding collar, forces
the said sleeve back against the action of the spring and carries the outer part
of the clutch out of contact with the inner part thereof and so breaks the trans-
mission connection between the shaft and the sleeve. The disc, with its bolts,
is moved back with the outer part of the clutch. Motion may be transmitted
from the sleeve by belt, chain, spur wheel or other gearing. The outer part of
the clutch may be used as a drum for a band brake which comes into action
by further depressing the pedal lever.
This construction while adding little, if anything to the outside dimensions
of the clutch secures ample strength and a certain grip.
As it is very undesirable that, say, the gear changing mechanism should be
operated while the clutch is in positive engagement, we prevent the same auto-
matically by the following means. We provide the pedal or other operating
lever with an arm at its fulcrum end and link the said arm to one end of a
small lever, the other end of which is provided with a detent or the like. This
detent is adapted to engage in a rack or racks carried by the gear changing
lever or levers. And the parts are so arranged that the said detent engages in the
said rack or racks only when the clutch is in positive engagement; the action
of depressing the pedal lever to its intermediate or lowest position disengages
the detent from the rack or racks, thus allowing the gear to be changed either
when the clutch is in only frictional engagement or when it is out of engage-
ment altogether. If desired the parts may be so arranged that the locking
device will allow the gear to be changed only when the clutch is out of engage-
ment altogether.
We do not confine ourselves strictly to the above description which is intended
to indicate the nature of our invention without excluding modifications or other
suitable applications thereof.
Dated this 29th day of July 1899
Improvements in or relating to Driving Gear for Autocars and
other Machinery.
We, HENRY THOMAS DAWSON and HENRY ALFRED DAWSON, both of Stour
Street, Canterbury, in the County of Kent, Engineers, do hereby declare the

page_text: 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: -
Our invention relates to driving gear for autocars and other machinery, and
has for its objects to provide, firstly, a compound clutch adapted to combine the
qualities of both a friction clutch and a positive clutch, and secondly, a locking
device to be used in conjunction with the said clutch and adapted to prevent
operation of another part or parts of the mechanism while the above mentioned
clutch is acting as a positive clutch.
The first part of our invention consists essentially in introducing, between
the parts of a friction clutch, one or more bolts which engage permanently in
apertures or the like in one part of the clutch and are capable of being moved
80 as to engage also in corresponding apertures or the like in the other part of
the said clutch when desired.
The second part of our invention consists essentially of a detent or the like
adapted to engage in a rack or the like on the gear changing or other mechanism
so as to prevent such mechanism being operated when the clutch is in positive
or frictional engagement, the said detent being actuated automatically by the
mechanism which operates the said clutch.
And in order that our invention may be properly understood, we will describe
the same with the aid of the accompanying drawings, wherein
Figure I is an elevation mostly in section of the general arrangement,
Figure II is a face view of the clutch, and
Figure III is an elevation of a pair of cams,
Figures IV, V and VI show diagrammatically three different relative posi-
tions of the said cams.
The same numerals refer to the same parts throughout the drawings.
In the drawings our improved clutch is shown as applied to a case where
rotary motion is to be transmitted from a horizontal power shaft 2 to a sleeve 3
surrounding the said shaft; though it will be readily understood that our
invention is readily applicable to other cases. The friction clutch may be of
any suitable construction such as the well known cone clutch shown in Figures I
and II. One part, say the inner 4, is rigid with the shaft, while the outer part 5
is rigid with the sleeve. The webs 6, 7 of the inner and outer parts of the
clutch are provided with one or more corresponding apertures 8, 9; and into
a space arranged between the said webs is introduced a loose, concentric disc 10
carrying one or more transverse bolts 11 which project beyond both surfaces of
the said disc. The disc is impelled towards the web 6 of the inner part of the
clutch by a suitable spring or springs, such as the expansion springs 12 carried
in recesses 13 in the inner face of the web 7 of the outer part of the clutch.
One or more longitudinal pins or keys 14, each engages by one end with the
said disc 10 and by the other end with a flanged or grooved collar 15 sliding
on the said sleeve. The sleeve 3 and outer part 5 of the clutch are normally
forced in the direction of the inner part 4 by an expansion spiral spring 16
upon the shaft 2 bearing against a fixed collar or stop 17 on the said shaft
in one direction, and the adjacent, flanged, or collared end 18 of the sleeve 3 in
the other direction. Normally, therefore, the spring 16 tends to throw the
friction clutch. into action and the springs 12 tend to throw the bolts 11 of the
positive clutch, into action. These tendencies may be controlled by any suit-
able means such as a bell cranked or other lever, one arm 19 of which is forked
and is adapted to actuate the flanged or grooved sliding collar 15 while the other
arm 20 is linked to a pedal or other lever 21, as shown in dotted lines in Fig. I.
Or, as preferred, we mount loosely on the sleeve between the collar 15 and a
suitable abutment (such as the plate 22 supported say by bolts 23 from a fixed
part 24) a pair of face cams 25, 26. These cams are provided with perforated
lugs 27, 28 respectively, adapted to receive the one ends of two rods 29, 30 the
other ends of which are jointed by a suitable link 31 to the pedal lever 21.

page_text: When the pedal lever is at its highest position (t which it may be normally
impelled by a spring such as 32) the cams 25, 26 close together (Figs. III
and IV), the spring 16 forces the sleeve 3 in the direction of the arrow and
causes the outer part 5 of the friction clutch to engage with the inner part 4,
and the springs 12 are allowed to force the disc 10 and bolts 11 in the direction
of the said inner part 4 of the clutch. When the bolts coincide with the aper-
tures 8 the springs 12 cause them to enter such apertures and thus positively
engage the clutch. By depressing the pedal lever to an intermediate position
the cams are rotated a certain distance in opposite directions and the cam 26
is forced back from the cam 25 carrying the collar 15 against the flanged end 18
of the sleeve. The said collar, acting through the keys 14, draws back the
disc 10 against the web 7 of the outer part 5 of the clutch and so withdraws
the bolts 11 from the web 6 of the inner part 4 of the clutch. The clutch then
remains engaged by friction only under the influence of the spring 16, this
position being shown in Figs. I and V. By further depressing the pedal lever
the cams 25, 26 are further rotated and spread apart, (Fig. VI) and the back
of the cam 26 acting on the flanged end 18 of the sleeve 3 through the sliding
collar 15, forces the said sleeve back against the action of the spring 16 and
carries the outer part 5 of the clutch out of contact with the inner part 4 thereof,
and so breaks the transmission connection between the shaft 2 and the sleeve 8.
The disc 10, with its bolts 11, is moved back with the outer part of the clutch.
The action is the same in effect with the bell crank lever 19, 20 but we find
the cam arrangement gives a positive action well adapted to operating the
clutch in successive stages and. while powerful, sets up little strain on the
parts concerned. Motion may be transmitted from the sleeve by chain (33),
belt, spur wheel, or other gearing. The outer part of the clutch may be used
as a drum 34 for a band brake which may be adapted to be brought into action
by still further movement of the lever 21.
This construction while adding little, if anything, to the outside dimensions
of the clutch secures ample strength and a certain grip.
As it is very undesirable that, say, the gear changing mechanism should be
operated while the clutch is in positive engagement, we prevent the same auto-
matically by the following-means. We provide the pedal or other operating
lever 21 with a vertical arm 35 at its fulcrum (36) end and connect the said
arm by a link 37 to one end of a small lever 38 the other end of which is pro-
vided with a detent or the like 39. This detent is adapted to engage in a rack
or racks 40 carried by the gear changing lever or levers 41. And the parts
are so arranged that the said detent engages in the said rack or racks only
when the clutch is in positive engagement by the bolts as indicated in Fig. I.
The action of depressing the pedal lever 21 to its intermediate or lowest position
disengages the detent from the rack or racks, thus allowing the gear to be
changed either when the clutch is in only frictional engagement or when it is
out of engagement altogether. It will be obvious that the parts may be so
modified that the locking device will allow the gear to be changed only when
the clutch is out of engagement altogether.
We do not confine ourselves to the above description but hold ourselves at
liberty to make such modifications as fairly fall within the scope of our invention.
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. In driving gear, the combination with the two parts of a friction clutch,
of one or more bolts which engage permanently in apertures or the like in one
part of the clutch and are capable of being moved so as to engage in corre-
sponding apertures or the like in the other part of the said clutch, for the pur-
pose set forth.
2. In driving gear, a combined friction and positive clutch constructed,

page_text: arranged and adapted to operate substantially as herein described, and as illus-
trated in the accompanying drawings.
3. In a clutch of the kind referred to in Claim 1 hereof, the employment of
a disc located between the two parts of the friction clutch and carrying the
bolts.
4. In combination with a clutch of the kind referred to in Claim 1 hereof,
means for moving the said bolts comprising a lever so arranged that in three
several positions of the said lever the clutch engages positively as well as fric-
tionally, engages frictionally only, or is disengaged altogether, respectively.
5. In driving gear, the combination with a clutch and means for operating
the said clutch, of a detent or the like adapted to engage in a rack or the like
on the gear changing or other mechanism when the said clutch is in positive or
frictional engagement, the said detent being actuated automatically by the
mechanism which operates the said clutch, substantially as and for the purpose
set forth.
6. In driving gear, the combination with a clutch of the kind referred to in
Claim 1 hereof, and means for operating the said clutch of the kind referred
to in Claim 4 hereof, of a locking device constructed, arranged, and adapted to
operate substantially as herein described, and as illustrated in the accompanying
drawinge
Dated this 31st day of May 1900.
DOUGLAS LEECHMAN, M. Cy. E.I.,
Fellow of the Chartered Institute of Patent Agents,
18, Hertford Street, Coventry,
9, Exchange Chambers, New Street, Birmingham, and
75, Chancery Lane, London, W.C., Patent Agent for the Applicants.