Abstrict
An electric heater for central buffer couplings, with a heating
element introduced into a groove of the coupling head. The heating
element is covered to the outside. To reduce damage to the heating
elements and to prolong the service life of the heater, the heating
element in the groove is filled with silicone material, which forms
the outer cover and is a flowable single-component material, which
undergoes crosslinking at room temperature under the action of atmospheric
humidity.
Claims
What is claimed is:
1. A central buffer coupling electric heater, comprising:
a coupling head with a portion defining a groove, said coupling
head includes coupling means for connecting to another coupling
head of another vehicle;
a heating element disposed in said groove, said heating element
having an outwardly directed side;
a silicone material forming an outer cover, covering said heating
element on said outwardly directed side, said silicone material
holding said heating element in said groove, said groove being substantially
filled with silicone material and forming said outer cover, said
silicone material being a flowable single-component material that
undergoes crosslinking at room temperature under the action of atmospheric
humidity.
2. The electric heater in accordance with claim 1, wherein said
silicone material sufficiently maintains its elasticity in the temperature
range from at least -40.degree. C. to at least +200.degree. C.
3. The electric heater in accordance with claim 1, wherein said
silicone material has electric insulation with a dielectric strength
greater than or equal to 12 kV/mm and thermal conductivity.
4. The electric heater in accordance with claim 2, wherein said
silicone material has electric insulation with a dielectric strength
greater than or equal to 12 kV/mm and thermal conductivity.
5. The electric heater in accordance with claim 1, wherein said
silicone material has dielectric strength greater than or equal
to 12 kV/mm at good thermal conductivity.
6. A central buffer coupling for coupling vehicles, the coupling
formed by the steps comprising:
providing a coupling head with a portion defining a groove, said
coupling head includes coupling means for connecting to another
coupling head of another vehicle;
introducing a heating element into said groove, said heating element
having an outwardly directed side;
filling the groove with a silicone material and covering said heating
element on said outwardly directed side to form an outer cover,
said silicone material holding said heating element in said groove,
said silicone material being a flowable single-component material,
said flowable material undergoing crosslinking at room temperature
under the action of atmospheric humidity after filling the groove
and covering the heating element.
7. The central buffer coupling in accordance with claim 6, wherein
said silicone material sufficiently maintains its elasticity in
the temperature range from at least -40.degree. C. to at least +200.degree.
C.
8. The central buffer coupling in accordance with claim 6, wherein
said silicone material has electric insulation with a dielectric
strength greater than or equal to 12 kV/mm and thermal conductivity.
9. A method of forming a central buffer coupling for coupling vehicles,
the method comprising the steps of:
forming a coupling head with a portion defining a groove, said
coupling head including coupling means for connecting with another
coupling head of another vehicle;
introducing a heating element into said groove, said heating element
having an outwardly directed side;
filling the grove with a silicone material and covering said heating
element on said outwardly directed side to form an outer cover,
said silicone material holding said heating element in said groove,
said silicone material being a flowable single-component material;
curing the flowable material whereby the material undergoing crosslinking
at room temperature under the action of atmospheric humidity after
filling the groove and covering the heating element.
10. The method in accordance with claim 9, wherein said silicone
material sufficiently maintains its elasticity in the temperature
range from at least -40.degree. C. to at least +200.degree. C.
11. The method in accordance with claim 9, wherein said silicone
material has electric insulation with a dielectric strength greater
than or equal to 12 kV/mm and thermal conductivity.
12. The method in accordance with claim 9, wherein:
said coupling means is for an automatic railway controlled buffer
coupling of two railroad vehicles.
13. The electric heater in accordance with claim 1, wherein:
said coupling means is for an automatic railway controlled buffer
coupling of two railroad vehicles.
14. The central buffer coupling in accordance with claim 6, wherein:
said coupling means is for an automatic railway controlled buffer
coupling of two railroad vehicles.
Description FIELD OF THE INVENTION
The present invention pertains to an electric heater for central
buffer couplings, whose heating element is introduced into a groove
of the coupling head and is covered to the outside.
BACKGROUND OF THE INVENTION
Central buffer couplings of the Scharfenberg design have been known,
in which an approximately semicircular groove, into which a heating
element is placed, is provided in the buffer surface of the coupling
head in the area of the centering cone and of the funnel. The heating
element shall keep the front faces and the coupling mechanism free
from ice and snow in the winter and ensure the function of the coupling.
The groove is closed to the outside by a hard solder, which forms
part of the buffer surface. Only low-melting hard solders, e.g.,
expensive silver filler, can be used as hard solders, because there
is a risk of damage to the heating element at higher processing
temperatures.
The use of soft solders with lower melting point proved to be unsuitable,
because the melting point of the soft solder was frequently reached
at the required heat output of the heating element.
It has also been known that the groove can be closed to the outside
by welded-in cover plates. The possible warping of the cover plates
as well as of the front plate due to the increased supply of heat
during welding must be borne in mind and taken into account. Uneconomical
preparatory procedures of the groove with ground contact for the
cover plate and uneconomical finishing operations, especially the
leveling of the weld seam, are necessary. Besides the possible damage
to the heating element due to the welding process, there always
is a risk of penetration of moisture into the cavity and consequently
of damage to the heating element.
SUMMARY AND OBJECTS OF THE INVENTION
The primary object of the present invention is therefore to improve
an electric heater for central buffer couplings and/or a method
of providing such a heater wherein the manufacture and assembly
are economical and simple, and damage to the heater will be reduced
and the service life of the heater will be prolonged.
According to the invention, an electric heater for central buffer
couplings is provided, with a heating element which is introduced/provided
into/in a groove of the coupling head and is covered to the outside.
The heating element is held in the groove with a silicone material.
The groove is filled with the silicone material and forms the outer
cover. The silicone material is a flowable single-component material
that undergoes crosslinking at room temperature under the action
of atmospheric humidity.
The silicone material preferably sufficiently maintains its elasticity
in the temperature range from at least -40.degree. C. to at least
+200.degree. C. The silicone material preferably has good electric
insulation (dielectric strength greater than or equal to 12 kV/mm)
at good thermal conductivity.
The central buffer coupling may be an automatic buffer coupling
as is known from U.S. Pat. No. 4,375,857 (which is hereby incorporated
by reference) but with the heating arrangement as described herein.
The coupling concepts on which these automatic buffer couplings
are based is discussed in U.S. Pat. No. 2,161,724 (which is hereby
incorporated by reference).
The various features of the novelty which characterize the invention
are pointed out with particularity in the claims annexed to and
forming a part of this disclosure. For a better understanding of
the invention, its operating advantages and specific objects attained
by its uses, reference is made to the accompanying drawings and
descriptive matter in which a preferred embodiment of the invention
is illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is an electric heater for a central buffer coupling with
heating element introduced into the heater.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the only drawing in particular, the present invention
comprises an electric heater for central buffer couplings and a
method of forming the buffer coupling with heater. The method includes
introducing a heating element 1 of the heater into a groove 2 of
a coupling head 3 and is covered to the outside. To reduce damage
to the heating elements 1 and to prolong the service life of the
heater, the heating element 1 in the groove 2 is filled with silicone
material 4, which forms the outer cover. This silicone material
4 is a flowable single-component material, which undergoes crosslinking
at room temperature under the action of atmospheric humidity.
The electric heater according to the present invention for a central
buffer coupling includes the heating element 1, which is provided
in the groove 2 of the coupling head 3. The heating element 1 is
disposed in the groove 2 and is held in the groove by means of the
elastic adhesive sealant. The adhesive sealant used is the silicone
material 4. The groove 2 filled with the silicone material 4 completely
up to the edge of the buffer surfaces forms a closure, with the
outer surface of the material 4 being the outer closure of the groove
2 or the outer cover of the coupling head heater arrangement.
The silicone material 4 is a flowable single-component material
at room temperature, which is crosslinked or undergoes elastic curing
at room temperature under the action of atmospheric humidity.
The silicone material is designed to be such that it sufficiently
maintains its elasticity in the temperature range from at least
-40.degree. C. to at least +200.degree. C.
The silicone material used is also characterized by a good electrical
insulation with a dielectric strength greater than or equaling 12
kiloVolt per mm (kV/mm) at good thermal conductivity.
While a specific embodiment of the invention has been shown and
described in detail to illustrate the application of the principles
of the invention, it will be understood that the invention may be
embodied otherwise without departing from such principles.
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