U.S. patent number 3,831,004 [Application Number 05/383,453] was granted by the patent office on 1974-08-20 for electric heater.
This patent grant is currently assigned to Fast Heat Element Manufacturing Co., Inc.. Invention is credited to Ray Wallstrom.
United States Patent |
3,831,004 |
Wallstrom |
August 20, 1974 |
ELECTRIC HEATER
Abstract
A cartridge or band heater having an internally threaded bushing
secured thereof affording a secure mounting for electric wires or a
conduit containing such wires.
Inventors: |
Wallstrom; Ray (Hoffman
Estates, IL) |
Assignee: |
Fast Heat Element Manufacturing
Co., Inc. (Chicago, IL)
|
Family
ID: |
23513223 |
Appl.
No.: |
05/383,453 |
Filed: |
July 27, 1973 |
Current U.S.
Class: |
219/535; 219/523;
439/472; 338/241 |
Current CPC
Class: |
H05B
3/06 (20130101); H05B 3/565 (20130101); H05B
3/56 (20130101) |
Current International
Class: |
H05B
3/58 (20060101); H05B 3/54 (20060101); H05B
3/06 (20060101); H05b 003/58 () |
Field of
Search: |
;219/523,535
;338/238,239,240,241,242 ;339/13R,13C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mayewsky; Volodymyr Y.
Claims
I claim:
1. An electric heater having flexible lead-in wires extending
therefrom and an electrical heating element, a metal housing for
said element, electrical insulation for said element and wires, and
a metal bushing and clamp assembly, said assembly comprising an
internally threaded metal bushing fixedly secured at one of its
ends to one end of said metal housing and through which said
lead-in wires extend, electrically insulated flexible current
supply wires electrically connected to said lead-in wires, and an
externally threaded rigid clamp fitting through which said supply
wires extend, said clamp fitting being screw threaded into said
bushing, said supply wires being secured to said clamp fitting.
2. The heater recited in claim 1, in which the heater is a
cartridge.
3. The heater recited in claim 1, in which the wire connections are
enclosed within the bushing and fitting.
4. The heater recited in claim 1, in which the heater is a band and
the bushing is brazed to the outside surface of the band and
projects radially therefrom.
Description
The invention relates to improvements in cartridge and band heaters
and is more especially concerned with the provision on such heaters
of novel means to facilitate connecting flexible armored cable or a
rigid conduit thereto. More particularly, the cartridge or band
heater is fitted on its connection end with a bushing that is
brazed or otherwise integrally secured thereon and which is
internally threaded to receive a conventional fitting of a type
used to secure a cable or conduit to a mounting. Cartridge heaters
are generally used where concentrated heat is desired and space is
limited. Such uses include, but are not limited to, heating of
dies, platens, process machinery, molds, melting pots and package
machinery sealing jaws.
It is therefore an object of the invention to provide cartridge and
band heaters of improved construction.
Another object is to provide a heater band or cartridge with novel
means to secure an armored cable or conduit thereto.
Another object is to provide a heater band or cartridge with an
integral female bushing.
Another object is to provide a cartridge or band heater of the
character referred to which is not difficult or expensive to
manufacture, is very easy to use and install and which is highly
efficient in use.
Other objects and advantages of the invention will become apparent
with reference to the following description and accompanying
drawings.
In the drawings:
FIG. 1 is a perspective view of a cartridge heater embodying the
invention.
FIG. 2 is a side elevational view of the cartridge heater showing
it connected to a flexible cable and partly in section.
FIG. 3 is an elevational view of a band heater embodying the
invention and showing parts in section.
Referring to the exemplary embodiments of the invention shown in
the accompanying drawings, and particularly to FIGS. 1 and 2, the
cartridge heater 11 includes a stainless steel shell emclosing a
heater (not shown) which has lead wires 12 extending from one end
for connection with a source of electric current. For a purpose to
be made apparent presently, the end of the cartridge having the
wires 12 extending therefrom is provided with a bushing 13, that is
brazed or otherwise fixedly secured to the cartridge. This bushing
projects beyond the related end of the cartridge and is internally
threaded, as at 14.
In use, the wires 12 are connected, as at 15, to the ends of wires
16 contained in a sheathed cable 17 which is connected to a source
of electric current. The insulated connections 15 are worked back
into the interior of the bushing, as shown. The sheathed cable is
then secured against withdrawal, and the connections 15 are
concealed, by a conventional externally threaded fitting 18 which
is threadedly engaged with the internal threads 14 of bushing 13.
The fitting includes the usual movable clamp strap 19, which is
held firmly against the sheathed cable 17 by screws 21.
In the FIG. 3 illustration of a band heater 22, said heater is
provided with a bushing 13 that is brazed or welded to the outside
surface thereof and which has lead-in wires 23 extending
therethrough. In this embodiment, the wires 23 are each connected
within the bushing to one of a pair of wires 24 leading to a source
of electric current supply. An externally threaded fitting 25 is
screw-threaded into the bushing as previously described. In this
embodiment, there is shown a different type of fitting which is
formed with a clamp portion 26 designed to receive and clamp the
end of a rigid conduit 27 or a flexible armored cable.
The lead-in wires 12 or 23 may be lengthened as desired, and
preferably they may be connected remote from the heater as to keep
the point of connection as cool as possible. Also, the bushing 13
may be hexagonal or of any other desired straight sided shape,
instead of cylindrical as shown, where the assembly is designed to
bear against an adjacent member to prevent relative turning or of a
shape required for grasping by a tool.
It should be evident that either type of clamp fitting 18 or 25 may
be used with either type of heater illustrated, such use being
determined by the type of external wiring used. Also, it is
apparent that there is provided a firm connection between the
cartridge or band heater and its connecting wires.
Although I have described preferred embodiments of my invention, in
considerable detail, it will be understood that the description
thereof is intended to be illustrative rather than restrictive, as
details of the structure may be modified or changed without
departing from the spirit or scope of the invention. Accordingly, I
do not desire to be restricted to the exact construction shown and
described.
* * * * *