Improvements in Driving Gear for Motor Cars.
Year: 1896

page_text: Date of Application, 2nd June, 1896-Accepted, 8th Aug., 1896
[Communicated from abroad by THE GASMOTOREN FABRIK DEUTZ, of Koeln-
Deutz, in the German Empire, Manufacturers.]
Improvements in Driving Gear for Motor Cars.
I, CHARLES DENTON ABEL, of 28 Southampton Buildings, in the County
of London, Consulting Engineer and Chartered Patent Agent, 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 motor cars that are driven by a motor running with
constant speed, which motor is connected with the road wheels of the vehicle by
toothed gearing, so arranged as to enable the latter to be driven either at a fast or
at a slow speed. The present improvement relates to the combination with such
variable speed gear of automatically acting mechanism whereby when the gear is
changed to the fast speed, the gear for the slow speed is prevented from being
carricd round thereby, thus preventing noise and preserving the gear from useless
wear.
One arrangement of the said mechanism is shewn at Figures 1 and 2 on the
accompanying drawing, in which Figure 1 shews a side view and Figure 2 a cross
section thereof.
The main driving shaft A is driven either directly or indirectly at a constant
speed in one and the same direction by a motor engine C of any suitable kind.
It carries two loose spur wheels c and m which gear respectively with the spur
wheels d and n on the intermediate shaft B. If the one wheel c be coupled with
the main-shaft by the engagement of the clutch parts I and II, the shaft B will
be rotated through wheel d at a quick speed.
If on the other hand the other wheel m be coupled with the shaft A by the
engagement of the clutch parts I and III, the shaft B will be driven at a slow
speed through the wheels m n. The motion of the shaft B is transmitted either
directly as shewn, or through another intermediate shaft, to the road wheels of
the vehicle.
In the construction of such variable speed gear heretofore employed, the
wheels d and n were both fixed on the intermediate shaft. In consequence
hereof, when the one pair of wheels were coupled with the motor shaft, the idle
pair were obliged to run too. This causes, in particular with the quick speed,
that is, when the motion is transmitted through c and d, a detrimental noise and
useless wear, inasmuch as the shaft B which is running at a considerable speed,
will impart a very high speed to the pinion m through the wheel n, owing to the
high ratio of transmission, and at this high speed there will be a considerable
impact between the teeth of the gear owing to the unavoidable inequalities in the
motion of the motor.
The present improvement consists in avoiding this disadvantage, by fitting the
slow speed wheel 'n loose on the intermediate shaft B, and fixing or forming
thereon a ratchet wheel e with which gears a spring pawlf fixed on the shaft B.
Thus when the vehicle is driven at the slow speed through the gear m and n,
the wheel n will carry round shaft B by means of the ratchet and pawl connec-
tion ef. When, on the other hand the vehicle is driven at the quick speed
through the gear c, d, the gear m, n will remain at rest, as the pawl will then
travel round the ratchet wheel e without carrying it round. In order to prevent

page_text: any noise from impact of the pawl with the ratchet teeth during this motion, the
pawl is made sufficiently massive to be caused to fly off from the ratchet teeth
by the centrifugal action, produced by the quick rotation of shaft B; a stop i may
be provided for limiting this action.
Figures 3 and 4 shew respectively a longitudinal section and a cross section on
line X X of a modification in which a frictional ratchet device of known
construction is employed in place of the pawl and ratchet device of the first
arrangement. In this case the wheel n for the slow speed, which is loose on
shaft B as before, is formed hollow, with cam surfaces n¹ on the inner periphery,
and on the shaft B is fixed a disc k with cylindrical rim k' which projects into the
hollow wheel n, and carries a series of loose wedges o, having by preference a
leather surface fitting on the disc, between which wedges o and the cam surfaces n¹
of n are placed rollers p. Thus on the wheel n being driven in the direction of
the arrow for the slow speed as before, the cam surfaces n' thereof will cause the
rollers to jam the wedges o tight on to the rim and the disc will consequently
be carried round. On the other hand, when the shaft B is being driven at the
quick speed by the gear cd, the wedges o, in being carried forward relatively to
the cam surfaces of wheel n by the disc k, into the position shewn at Figure 3, the
rollers p will be free of the cam surfaces, and will release the wedges, and the
disc will revolve without carrying round the wheel n.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is :-
1. In variable speed gear for motor cars wherein the motor shaft A running at
a constant speed imparts a fast or slow speed to an intermediate shaft B by fast
speed gear c d and slow speed gear m n, the combination with the intermediate
shaft B of a slow speed toothed wheel n mounted loose thereon and connected
thereto by a ratchet device adapted to carry the shaft B round with the said wheel
when this is driven by shaft A and wheel m, but which ratchet device leaves the
wheels m n stationary when the intermediate shaft B is driven by the quick speed
gear, substantially as and for the purpose set forth.
2. In variable speed gear for motor cars wherein the motor shaft A running at
a constant speed, imparts a fast or slow motion to an intermediate shaft by means
of fast speed gear c d and slow speed gear m n, the combination with the inter-
mediate shaft B of a slow speed toothed wheel n mounted loose thereon and
carrying a ratchet wheel e gearing with a pawl f carried by the shaft B, which
ratchet gear transmits the motion to the shaft B when the wheel n is being driven
by shaft A and wheel m, but when the shaft B is driven through the fast speed
gear, the pawlf will be automatically disengaged from the ratchet wheel e by
centrifugal action, and will thus prevent the motion of shaft B from being
imparted to the slow speed gear, substantially as described.
Dated this 2nd day of June 1896.
ABEL & IMRAY,
Agents for the Applicant.