Improvements in or relating to the Wheels and Axles of Tram-cars.
Year: 1892

page_text: Date of Application, 25th June, 1892-Accepted, 1st Oct., 1892
COMPLETE SPECIFICATION.
Improvements in or relating to the Wheels and Axles of Tram-cars.
A communication from CARL LÜHRIG, of Reichstrasse 30, Dresden, in the
German Empire, Mining Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
Member of the Institution of Mechanical Engineers, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
The subject of this invention is an improvement in tram-car axles. Hitherto the
wheels have been fast on these axles, but it has been found that, at turnings,
junctions, curves or the like, where a difference in the width of the line or track is
apt to occur, some of these fast wheels are dragged along instead of rolling, and
thereby cause a considerable strain or resistance. Many attempts have been made
therefore to arrange the wheels in such a manner that they should be capable both
of running independently of each other and of automatically adjusting the distance
between them, at junctions or turnings.
Most of the arrangements hitherto proposed for the purpose have been found
deficient in practice, partly because they were too complicated and partly on
account of the damaging influence they produced upon the power of resistance of the
axles. This invention differs from the devices hitherto known, in this important
particular, that the wheels arranged in accordance with it are mounted upon solid
axles which, though the wheels are loose thereon to a certain extent, are adapted
to turn with the wheels.
This object is attained by the simple arrangement illustrated in the accompanying
drawings.
Figs. 1 to 5 show one form of apparatus, Fig. 1 being a vertical section of the
complete apparatus, Fig. 2 a face view of the hub, Fig. 3 a face view of the boss,
and Figs. 4 and 5 are plans partly in section of the hub respectively showing the
stops in their outward and inward positions.
Figs. 6, 7, 8 show views of another form of the apparatus, Fig. 6 being a vertical
section of the complete apparatus, Fig. 7 a face view of the clutch and Fig. 8 a
horizontal section through part of Fig. 6.
Figs. 9, 10 and 11 illustrate a further modification, Fig. 9 being a vertical
section of the complete apparatus Fig. 10 a face view of the clutch and Fig. 11 a
plan of the underside of same.
Upon the axle 2 is loosely arranged the hub or boss 1 of the wheel, adapted to
engage with a sleeve or clutch 3 secured on the same axle. This sleeve causes
both the axle and wheel to perform the required movements and only enables the
wheel to run independently forward or backward within certain limits, the space
between the wheels being adjusted to suit requirements at the same time.
In the form of apparatus shown in Figs. 1 to 5 of the drawings either the
boss or the sleeve or clutch 3 is provided with spring controlled studs or
stops 4 adapted to engage with corresponding recesses or slots 5 in the other
part. In the present case it will be seen that the two stops 4 enter recesses 6
provided for them in the sleeve 3 and are retained therein by means of screwed
plates 7. They rest upon springs 8 which tend to force them outwardly. In
the boss are provided two slots 5 whose orifices, are limited by correspondingly
slotted plates 9, and the arrangement is such that one of the stops 4 only can
engage a slot at a time, the stops being arranged diametrically opposite each

page_text: other while the slots or recesses 5 are not so arranged. When in travelling
over a curve a wheel has the tendency of turning somewhat quicker than its axle,
while the other wheel on the contrary manifests a tendency of falling back, these
opposite tendencies are overcome and compensated by the springs controlling the
engaging studs which are forced back so as to release the hub of one wheel
from engagement and allow it to yield to its accelerating tendency. But the
spring-controlled stud which in the meantime has been out of gear now engages
its corresponding recess, and thereby limits the extent of this accelerated motion
of the wheel which in no case will cover a greater distance than a few centi-
metres. When the wheel has completed its accelerated movement, it is necessary
that the axle should make up for the distance it has lost. For this purpose the
pawl or stop just engaged is forced back again, and the one just released, allowed
to return into gear, whereby the movement of the axle is in its turn checked. In
performing these movements the wheel is capable of longitudinal displacement upon
the axle to an extent not exceeding 1 centimetre, a ring or collar 10 being loose in
the hub, admitting of such longitudinal adjustment.
In the forms shown in Figs. 6 to 8 a circular groove 15 occupying about three-
quarters of a circle is provided in the sleeve or clutch 3, while the hub 1 carries
one or more bolts or pins 14 adapted to engage in this groove.
Both the groove
at its ends and the pins or bolts 14 are bevelled or inclined inwardly and loosely
fit each other. In this arrangement also, therefore, provision is made for a slight
longitudinal displacement of the wheel upon the axle. When however the wheel
and axle have completed the required movements, the inclined surfaces of the
bolts and groove-ends by coming into contact tightly draw the wheel against the
clutch.
In the arrangement shown in Figs. 9 to 11, both upon the sleeve or clutch 3 and
upon the hub 1 of the wheel there are one or more projections 24, 25 adapted
loosely to engage with each other. The contact-surfaces are here too, slanting,
as in the arrangement previously described.
It will thus be seen that in all these arrangements the wheel is enabled, when
required, to accelerate or retard its motion somewhat in relation to the motion of
its axle.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is,-
1. A wheel and axle connection for tramcars in which provision is made for the
independent acceleration or retardation of motion, and for the simultaneous longi-
tudinal displacement of the wheels a sleeve or clutch (3) mounted upon the axle (2)
being for the purpose connected by means of spring-controlled stops or pawls (4)
with the loose hub or boss (1) of the wheel the arrangement being such that one
pawl or stop only can in each case engage with the corresponding recess or slot (5)
while the other stop or pawl does not get into engagement till a sufficient time after
the release of the first to enable the axle or wheel as the case may be to perform
the requisite independent movement substantially as described and illustrated in the
accompanying drawings.
2. A modification of the arrangement characterized in the preceding claim which
consists in connecting the hub or boss (1) of the wheel and the sleeve or clutch (3)
by means of bolts (14) engaging a circular groove (15) both the groove-ends and
the bolts being so bevelled that the contact of their respective inclined surfaces
may when the axle or wheel has performed the required movement draw the wheel
tightly against the sleeve or clutch substantially as described and illustrated in the
accompanying drawings.
3. Another modification of the axle characterized in Claim 1 consisting in pro-
viding both the bub or boss (1) of the wheel and the sleeve (3) of the axle with
lateral projections (24, 25) mutually engaging with each other and likewise

page_text: bevelled for the purpose indicated in the preceding claim substantially as described
and illustrated in the accompanying drawings.
Dated this 25th day of June 1892
ALFRED J. BOULT,
Chartered Patent Agent.