Improvements in Pushes and like Contacts for Electrical Circuits.
Year: 1898

page_text: Date of Application, 19th Aug., 1898.
Complete Canciónstina Laft 16th May 1800
Accanted 22nd July 1899
PROVISIONAL SPECIFICATION.
Improvements in Pushes and like Contacts for Electrical Circuits.
I, WALTER REGINALD LAMBERT, Electrical Engineer, of 18, Pattenden Road,
Catford Hill, in the County of Kent, do hereby declare the nature of this invention
to be as follows:
My invention relates to certain improvements in pushes and like contacts for
electrical circuits, and has for its objects the provision of a rubbing contact in
the action of pushing, thus removing any dust or chemically formed oxide or
the like which may act as non-conducting mediums, and also the improved.
economical construction of the appliance generally, which may, according to my.
invention have a china, porcelain or like base or mould.
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In carrying my invention into effect I prefer to use a china or porcelain barrel,
with a flanged and lettered face, having an inner flange attached to, or formed
upon it.
A plunger push with a square or polygonal cross section passes through
the two flanges, the outer and the inner, and projects beyond the preferably
recessed face of the outer for the purpose of depression. The square or polygonal
plunger carries a metallic mushroom spring, shaped like an inverted umbrella,
which when depressed, makes contact between two conèd or rounded heads, which
pass through opposite sides of the insulating barrel and form terminals externally..
A spiral or volute spring below this fixed contact piece surrounds the base of the
plunger and is held in place by a cap, screwed or otherwise attached to the barrel,
and the pressure necessary to complete the circuit is effected against the tension
of said spring.
The barrel and its accessories may be made of metal, if the two opposite contacts
be enclosed in insulating bushes with insulating flanges, and the closing cap be;
also insulated from the body.
I may make a locking push switch by causing the first pushing movement to
lock against a trigger catch, and a further pressure releasing said catch when
necessary.
The essential features of my invention are in the employment of a mushroom
fixed contact caused to impinge by pressure against two fixed contacts, thus com-
pleting the electrical circuit, and further in the general arrangement allowing
of the use of china or porcelain in making the base or barrel, which has hitherto,
not been attained.
1000

page_text: and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
-
My invention relates to certain improvements in pushes and like contacts for
electrical circuits and has for its objects the provision of a rubbing contact in
the action of pushing thus removing any dust or chemically formed oxide or
the like which may act as non-conducting mediums; and also the improved
econominical construction of the appliance generally, which may, according to my
invention have a china, porcelain, or like base or mould.
In order that my said invention may be the better understood I have appended
the accompanying sheet of drawings, in which Figure 1 is a sectional elevation of
the push or contact, Figures 2 and 3 respectively front and side elevations of the
split hemispherical contact, drawn to a larger scale, and Figure 4 is a perspective
view of the push or contact, externally. Similar letters of reference indicate
corresponding parts throughout the several views.
In carrying my invention into effect I prefer to use a china or porcelain barrel A
with a flanged face B, having an inner Hange C attached to, or formed upon it,
and a plunger push a with a square or polygonal shaft 6 passes through the two
flanges B and C, projecting beyond 1 for the purpose of depression to establish
electrical contact. The shaft or spindle b carries a hemispherical or mushroom
spring contact, split to afford elasticity. This is shown in detail by Figures 2
and 3. When the press button or push a is depressed, the split hemisphere c
is forced between two round or conèd heads d d which pass through opposite
sides of the insulating barrel A and form terminals as shown. A spiral or
volute spring s surrounds the base of the shaft 6 beyond the contact piece c and
is held in place by a cap m screwed or otherwise attached to the barrel A, and
the pressure necessary to complete the circuit is effected against the tension of
said spring s. The barrel A and flanges B and C may be made of metal, if the
terminals tt and contact heads d d be insulated by proper bushes and collars.
And in this case the closing cap m may be insulated from the barrel A.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
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First. In a push or like contact for use in electrical circuits the employment
and use of a barrel A. of insulating material in combination with a split hemi-
sphere or conèd spring contact c and two projecting contacts d d connected to
terminals tt substantially as and for the purposes herein described.
Second. In a push or like contact for use in electrical circuits the combination
of a hemispherical contact piece, split to ensure elasticity, with two fixed and
insulated contacts, so that pressure against the tension of a spring may close the
circuit there between, substantially as herein described.
Third. In a push or like contact for use in electrical circuits, the combination
of a metal barrel A, with an hemispherical split contact piece c and insulated
fixed contacts dd' and terminals tt substantially as herein described and shown
by the appended drawings.
of May. 1899.
FREDK. WALKER,
73, St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicant.