Improvements in Devices for Locking the Driving Mechanism of Bicycles or Tricycles to Prevent Theft.
Year: 1899

page_text: Date of Application, 19th June, 1899-Accepted, 29th July, 1899
COMPLETE SPECIFICATION,
Improvements in Devices for Locking the Driving Mechanism of
Bicycles or Tricycles to Prevent Theft.
I, ERNST ALBIN TROMMER, of Stenn, near Zwickau, Saxony, Germany, Theatre.
Proprietor, 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:-
-
My said invention relates to devices for rendering the driving mechanism of
a bicycle or tricycle inoperative when the wheel has been left standing and thus
preventing theft. The invention relates to that class of mechanism by means
of which one or other of the chain wheels is locked to or unlocked from its shaft.
so that the said chain wheel will be inoperative when the wheel is left standing.
The device consists of the details of construction hereinafter set forth and parti-
cularly pointed out in the claims.
In order to render the present specification more casily intelligible reference
is had to the accompanying drawings in which similar letters of reference denote
similar parts throughout the several views.
Fig. 1 is a vertical cross section through a chain wheel carried out according
to the invention.
Fig. 2 is a section on line - of Fig. 1..
Fig. 3 is a vertical cross section of a modified form of the device.
Fig. 4 is a section on line yy of Fig. 3.
Fig. 5 is a similar section to that of Fig. 4 showing the tumbler disengaged
and the bolts in position to snap into the recesses of the chain wheel when they
come round, and Fig. 6 is a similar sectional elevation showing the bolts locked
in their recesses by means of the tumbler.
Referring to Figs. 1 and 2 the chain wheel a is loosely mounted on the sleeve b
and has one of its faces recessed to form the lock casing a circular cover c being
provided to properly fit into the recess, said cover being fast on the driving
sleeve b. Within the lock casing are mounted the bolts d d adapted to pass
through recesses of the rim c¹ of said cover when projected out of the same and
engage recesses or sockets f formed in the interior of the rim of the chain wheel
so that the latter will be locked to the disc c and rotate with the sleeve b. Any
suitable mechanism may be employed for actuating the bolts d d by means of a
key g and tumbler h (Fig. 2) in the known manner. In the device shown at
Fig. 2 the bolt is coupled to the lower bolt by means of a pivoted lever k so
that when the key pushes back the tumbler h and raises the upper bolt the
lower one will also be projected out and when the recessed part of the chain
wheel comes round the said bolts will engage the same as stated. In this form
of the invention it is necessary to turn the chain wheel until the recesses or
sockets f f come into position over the bolts which is sometimes a tedious pro-
cedure. In order to avoid this necessity the construction shown in Figs. 3 to 6
is provided by means of which the bolts which are spring pressed outwardly
may be disengaged from the tumbler by means of the key and then will auto-
017

page_text: matically snap into their sockets in the chain wheel when the same comes round
being locked therein by the tumbler as hereinafter set forth.
Referring to Figs. 3 to 6 the bolts d d are spring pressed outwardly by means
of a strong spring whilst a downwardly pressed spring catch is provided on
the upper bolt said catch being adapted to engage in a recess of the tumbler h
and retain the same in its backward or disengaged position as shown at Fig. 5.
When the parts are in this position the spring r tends to push the bolts d d
against the interior rim of the chain wheel a said bolts passing through the
rim of the casing consequently as soon as the recesses f come round both
bolts will spring into the same and the chain wheel will be securely locked to the
sleeve b. As the bolts move outwardly the catch will be raised with the upper
bolt and withdrawn from the notch of the tumbler h so that the same may again
move forward under the influence of its spring and will enter the lower of the
two notches of the bolt d and thus secure the latter in its locked position.
When the parts are unlocked they will be returned to the position shown at
Figure 4 with the catch ready to engage the notch of the tumbler when the
wheel is to be again locked to the sleeve.
J It is immaterial in the present invention which of the chain wheels is provided
with the above described mechanism as also how many bolts are employed or
what particular construction of tumblers as these may be varied in many ways
without departing from the spirit of the present invention.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is
1. The combination of a chain wheel loosely mounted on its shaft and having
a recessed face a disc fast to the chain wheel shaft and forming a cover to said
recess sliding bolts attached to the interior face of said disc and capable of being
projected out at the edge of said disc and recesses in the interior rim of the said
chain wheel into which said bolts may engage and a lock mechanism to retain
said bolts in their outward or inward position substantially as described.
2. The combination of a chain wheel loosely mounted on its shaft and a disc
fast on the said shaft a recess in said chain wheel face to which the said disc
forms the cover a series of bolts mounted on said disc and adapted to slide out-
wardly and a tumbler mechanism to lock the same in their outward or inward
position recesses in the interior rim of the chain wheel in which the said bolts
engage and means in connection with one of the said bolts to lock the tumbler
back until the bolts have come into engagement with their recesses substantially
as described.
.
3. The combination of a recessed chain wheel a loosely mounted on its sleeve b
and having interior rim recesses of a disc e fast on the said sleeve and having
outwardly projectionable bolts d d a tumbler to lock the bolts in their extreme
positions and a catch 7 spring pressed towards the tumbler and mounted on the
bolt said catch being adapted to engage a notch in the tumbler and retain the
same out of engagement with the bolts until the recess of the chain wheel comes
round and the bolts are projected outwardly substantially as described.
Dated this 17th day of June 1899.
E. T. WHITELOW, A.M.Inst.C.E.,
70, Deansgate, Manchester, Agent for the Applicant.