U.S. patent number 3,748,373 [Application Number 05/244,122] was granted by the patent office on 1973-07-24 for electrical contact device.
Invention is credited to Roger Remy.
United States Patent |
3,748,373 |
Remy |
July 24, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
ELECTRICAL CONTACT DEVICE
Abstract
A linear electrical contact device comprising a central
conductor, a tubular braid of metallic threads, and a tubular braid
of interwoven insulating threads separating the central conductor
and the tubular braid of metallic threads. The tubular braid of
intermoven insulating threads forms a cord helically wound around
the central conductor and is thermo-welded to the central conductor
so as to be permanently secured thereto. The contact device can be
used in combination with a vehicle window slide to activate when an
object is caught in the window as the window is rolled up.
Inventors: |
Remy; Roger (Neuilly-Plaisance
93, FR) |
Family
ID: |
22921451 |
Appl.
No.: |
05/244,122 |
Filed: |
April 14, 1972 |
Current U.S.
Class: |
174/115; 174/29;
200/85R; 174/28; 200/61.23 |
Current CPC
Class: |
H01B
7/10 (20130101) |
Current International
Class: |
H01B
7/10 (20060101); H01b 007/22 () |
Field of
Search: |
;174/28,29,12R,113R,115
;200/61.41,61.24,61.23,85,86 ;340/272 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
966,167 |
|
Jun 1965 |
|
GB |
|
1,193,029 |
|
May 1970 |
|
GB |
|
1,640,743 |
|
Oct 1970 |
|
DT |
|
Primary Examiner: Gilheany; Bernard A.
Assistant Examiner: Grimley; A. T.
Claims
The embodiment of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A linear electrical contact device comprising a central
conductor, a tubular conductor surrounding said central conductor
and consisting of a braid of metallic threads, and a tubular braid
of interwoven insulating threads separating said conductors and
forming a cord helically wound on said central conductor, said cord
being secured to at least one conductor so as to prevent sliding
thereof with respect to said one conductor, said tubular braid of
metallic threads being impregnated with a composition ensuring an
homogeneous, waterproof and flexible contact device.
2. A contact device as defined in claim 1, wherein said central
conductor is made of stainless steel having a certain resistance
and wherein said cord is made of interwoven superpolyamide threads,
said cord being secured to said central conductor by passing
current through the central conductor which will cause thermal
welding of the cord onto the central conductor.
3. The combination of an extruded profile used in a vehicle window
slide and having an edge with a tubular housing, with a linear
electrical contact device inserted in said tubular housing, said
linear electrical contact device comprising a central conductor, a
tubular conductor surrounding said central conductor and consisting
of a braid of metallic threads, and a tubular braid of interwoven
insulating threads separating said conductors and forming a cord
helically wound on said central conductor, said cord being secured
to at least one conductor so as to prevent sliding thereof with
respect to said one conductor, said tubular braid of metallic
threads being impregnated with a composition ensuring an
homogeneous, waterproof and flexible contact device.
4. A contact device as defined in claim 3, wherein said central
conductor is made of stainless steel having a certain resistance
and wherein said cord is made of interwoven superpolyamide threads,
said cord being secured to said central conductor by passing
current through the central conductor which will cause thermal
welding of the cord onto the central conductor.
Description
This invention relates to a linear electrical contact device of the
type comprising two conductors arranged generally parallel and
separated by insulating elements, which allow the conductors to be
brought into contact by pressure applied at any position along the
length of the device for, for example, closing an electrical
circuit when the pressure is exerted and opening the circuit as
soon as the pressure is released.
It is known that recent industrial developments of such linear
electrical contact devices, in requiring both a certain amount of
miniaturization and a large amount of flexibility so as to permit
their general use for the security of electrically operated devices
such as car windows, have revealed frequent hazards due to
accidental closures of the circuit operated by such contact
devices.
It is the object of the present invention to overcome the above
drawbacks and, more particularly, to eliminate the risks of
accidental contacts between the two coaxial conductors which are
slightly spaced, on one hand, by using an helicoidal spacer element
having a great elasticity and, on the other hand, by using an
helicoidal spacer element which is permanently secured to at least
one of the conductors, so as to prevent any sliding thereof on such
conductor, and, finally, by using a tubular braid of metallic
threads which is impregnated with an elastomeric composition.
The novel characteristics of the invention as wells as others which
are related thereto and the advantages of the present invention
will be best understood by referring, by way of example, to the
following description of a preferred embodiment of the invention
and to the attached drawings in which:
FIG. 1 illustrates a partial longitudinal section of a portion of a
cable forming an electrical contact device in accordance with the
invention;
FIG. 2 illustrates a cross-section of the same cable taken along
line A-A' of FIG. 1;
FIG. 3 illustrates a cross-section taken along line B-B' of FIG. 1;
and
FIG. 4 illustrates a cross-section of the window-slide of a vehicle
door adapted for insertion of a linear electrical contact device in
at least one free edge thereof.
In FIGS. 1 to 3, there is shown a coaxial cable capable of
detecting the pressure applied thereto and to ensure the closure or
opening of an electrical circuit depending on whether or not the
cable is subjected to a radial pressure. The cable or linear
electrical contact device comprises a central conductor 1 spaced by
an helically wound insulator 2 from a conductive tubular braid 3
impregnated with an outside elastomeric composition 4.
The helicoidal insulating spacer 2 is novel in that:
A. On one hand, it comprises a braid, lace or cord formed of small
threads, preferably made of superpolyamide, interwoven tubularly so
that the flattening thereof in the form on a band facilitates, by
its own elasticity, the contact under the effect of a pressure as
well as the separation when the pressure is removed from the
coaxial conductors 1 and 3, and also the winding of such braid,
lace or cord in an helicoidal form.
b. On the other hand, due to the non-negligeable electrical
resistance of the central conductor 1, which is made of stainless
steel including a nickel chrome composition, the "joule" effect
resulting from the passage of an electrical current under low
voltage which is of sufficient amplitude so as to cause a suitable
heating of the central conductor 1 will cause the superpolyamide
braid 2 contacting the central conductor to be brought to its
melting point. This will very simply and economically cause the
permanent adhesion of the superpolyamide braid on the central
conductor 1, thus preventing all risks of subsequent sliding of the
braid on the central conductor, even under low radius flexures.
In addition, the peripheral tubular conductive braid 3 is
advantageously impregnated with an elastomeric composition 4 which
is deposited thereon in any convenient way such as, for example by
plunging it into a suitable bath, by conductive rollers, by
pulverization using a pistol etc . . .
The elastomeric composition may be of the type commercially known
as RHODORSYL RTV or RF4 sold by Rhone-Poulenc, which may be
vulcanized at room temperature, or be made of a neoprene adhesive
material having a resistance to crystallization, so as to maintain
a maximum flexibility, and, for example, have the following
composition in which the proportions are given in weight:
Polychloroprene resisting to crystallization such as the one known
commercially as WD or WRT of Dupont de Nemours: 50 to 100
Polychloroprene having an average crystallization and a high
viscosity, such as for example the one known commercially as WHV or
WHV 100 of DUPONT DE NEMOURS: 0 to 50 Extra light calcinated
magnesia: 4 Silicate of calcium (silene EF) 5 to 10 Zinc oxyde: 5
Phenolic antioxygene such as the one known commercially as Zalba of
DUPONT DE NEMOURS: 2 Phenolic resin, such as the one known
commercially as SP 560 of Schenectady of FRANCE: 15 to 20
The above composition will be used in solution, in an appropriate
solvent system, at the rate of 20 to 40 percent of dry extract,
providing respectively solutions for use either with a pistol or in
a bath.
It may also be mentioned that an improvement of the retification of
the film may be obtained by adding 2 to 10 percent of an isocyanate
of the type known commercially as Desmodur R or F of BAYER, but to
a disadvantage in the stability in pot. This isocyanate is added
immediately before use.
Due to the impregnation of the braid of metallic threads with an
elastomeric composition 4, the tubular assembly so formed becomes
much more homogeneous and much more appropriate for supporting
elastic deformations, even repeated, and at the same time for
returning to its initial shape after removal of the applied
pressure. The elimination of the risks of sliding of the helicoidal
winding 2 by thermal welding of such helicoidal winding on the
central conductor 1 permits to realize low radius flexures of the
linear contact device without incurring accidental contacts between
the two coaxial conductors 1 and 3.
It may also be mentioned that the impregnation of the elastomeric
composition 4 is also novel and advantageous in that it renders the
whole assembly waterproof, thus also reducing the risk of
deterioration of the contacts between the two coaxial conductors 1
and 3. In addition, this facilitates the sliding of the linear
contact device into an additional protective sheath, or in the
tubular housing 5 of at least one edge of an elastic profile 6 used
as a vehicle window guide slide, such as shown in FIG. 4. Such an
arrangement may be used to stop the operation of the electrical
device actuating the window when an obstacle such as a child head
is caught between the window and the frame of the door. It is to be
understood that other means of fastening the linear contact device
are also possible.
It is also be understood that the invention is not to be limited to
the embodiment disclosed above, by way of example, but that various
modifications may be made to such embodiment using equivalent
devices.
As an example of equivalent devices, it may be mentioned the
substitution of the "joule" effect to weld the hellical member 2 to
the central conductor by a high frequency heating process wherein
the linear contact device is passed through induction windings.
This would facilitate the continuous fabrication of the device and
obviate to use of electrical feeding contacts to permit the thermal
welding of the insulating braid 2 onto one of the conductors. In
addition, the elastomeric composition 4 could be replaced by a
vinyl plastic which would be jelled by such high frequency heating
or in an oven.
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