An Electrical Rolling Contact Making and Breaking Device.
Year: 1894

page_text: Date of Application, 8th Aug., 1894-Accepted, 8th Sept., 1894
COMPLETE SPECIFICATION.
An Electrical Rolling Contact Making and Breaking Device.
I, KARL AST of 38 Blumenstrasse, Gorlitz, in the Empire of Germany,
Headmaster, do hereby declare the nature of this invention and in what manner the
Bame is to be performed to be particularly described and ascertained in and by the
following statement :-
The present invention relates to a contact-making device in which contact-
making rollers of conducting material move over or under contact bars or rails
formed of small pieces of metal separated from one another by pieces of insulating
material said metal pieces being connected together in such a manner that the
circuit of a bell-operating battery is alternately opened and closed.
Several arrangements for carrying out this invention are illustrated in the
accompanying drawings in which:-
Fig. 1 is a contact-making roller with holder for use on doors or windows.
Fig. 2 is another construction of roller the arrangement being such that the
contact bar 1 (see Fig. 3) becomes unnecessary when the current is strong.
Fig. 3 shows the working surfaces of an arrangement of contact bars to form a
path for the contact-making roller.
Fig. 3 is a plan of the whole contact-making device applied to a door.
Fig. 4 is a side elevation of one contact bar provided with interrupting places.
Fig. 5 illustrates the application of a rolling contact to a door in perspective
view, and
Fig. 6 illustrates another application of the invention viz. to a drawer.
Figs. 1 and 2 can be understood without further explanation.
The contact bars shown in Figs. 3, 3^, 4 and 5, are constructed advantageously
in the following manner :-
A metal frame a bed which is made of U-form in cross section and has the
shape of an arc of a circle when employed in door contact-making devices is
hinged at s.
This frame serves to carry a series of metal plates efy which may be of any
desired thickness and are arranged at any desired intervals of distance apart from
one another. These metal plates efy are separated from one another by means of
intermediate insulating pieces ik of hard rubber (vulcanite) fibre or other
suitable insulating material.
These parts are fasteued preferably by means of screws so as to allow of readily
changing the contact pieces. In constructing the same care should be taken that
the several contact strips are in good conductive connection with the current
supply bar and that the working surface formed by the contacts and the insulating
pieces constitutes a good level path for the contact making roller.
It will be understood that the edges of the U-shaped bar 2 must not project into
this working surface see Figs. 4 and 5.
The other contact bar which is connected with the other pole of the battery is
constructed in a more simple manner because it has merely to form a continuous
contact surface for the contact-making roller which rolls along underneath it but it
must however be of the same shape as the other bar.
The electrical connections are illustrated in Fig. 5 in which B represents a
source of electric current and K a bell or ringing mechanism located at a suitable
point.
In Figs. 2 and 6 the electrical connections are but briefly indicated.

page_text: The mode of operation of the contact-making device is as follows:-
Whilst the door is closed the contact-making roller is situated exactly under the
insulating piece h. Now as soon as the door is opened the roller moves along
under the two contact bars but first makes at e a contact for a length of time
between the hars and 2, and thereby includes the bell in the circuit of the battery
so that an audible sigual or alarm is given during this contact.
In the arrangement of the roller (shown in Fig. 2) which may be employed
with stronger currents the electric current is supplied at m and passes without the
intermediary of the bar 1 (which may be dispensed with in this arrangement)
through the roller to the contact piece of the bar 2 whereby the circuit is
closed.
So long as the gradually opening door pushes the roller along under the
insulating piece the alarm bell will be silent but will sound again for a shorter time
and then for a very short time when the roller comes in contact with the brass
strip at and then at g.
By combining together different contact pieces (which can be all fastened in a
very convenient manner in the frame as shown in Figs. 3 and 4 and can likewise
be removed from the same) the most varied signals may be constituted in fact a
different signal for each door which is often of great importance.
But even in such cases where it is not important to be able to distinguish between
several signals this contact-making device is to be recommended on account of its
simple construction trustworthiness and durability. It is not liable to fail or get
out of order and any part thereof can be replaced by a new part at a minimum
expense.
The rolling contact can also be applied in a similar manner to Venetian blinds
or to drawers as in Fig. 6 but in such cases the contact bars must be made of straight
or rectilinear shape and be so arranged that the contact rollers can roll under the
same without difficulty with ease and with the formation of a good contact.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
An electrical rolling contact-making and breaking device in which contact pieces
such as ef are arranged in varying number position and length on straight or
arc-shaped bars such as 1 and 2 in combination with a roller such as for the
purpose of enabling the audible signals produced by the making or breaking of the
electric circuit at the several said contact pieces eg to be readily distinguished
from one another substantially in the manner and for the purposes herein before
described and illustrated by way of example in the drawings hereunto annexed.
Dated this 8th day of August 1894.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.