US3167736A

US3167736A - Electric heaters

Info

Publication number: US3167736A
Application number: US179361A
Authority: US
Inventors: Sidney J Temple
Original assignee: Edwin L Wiegand Co
Current assignee: Edwin L Wiegand Co
Priority date: 1962-03-13
Filing date: 1962-03-13
Publication date: 1965-01-26
Anticipated expiration: 1982-01-26

Description

7 Jan. 26, 1965 5. J. TEMPLE 3,167,736

ELECTRIC HEATERS Filed March 13, 1962 INVENTOR. 510N11 J-T.EMPLE /Mm w/zz/ A TTOR/VE/5 United States Patent Ofifice 3,167,736 ELECTRIC HEATERS Sidney J. Temple, littsburgh, Pa, assignor to Edwin L. Wiegand Company, Pittsburgh, Pa. Filed Mar. 13, 1962, Ser. No. 179,361 Claims. (Cl. 338-421) My invention relates to electric heaters, more particularly to a plug and socket connector for electric heaters, and the principal object of my invention is to provide new and improved constructions of this character.

The heater of my invention is particularly useful in places where clean working conditions do not prevail, such as in construction jobs and shipyards where electric heat is used for preheating or other purposes. On such jobs, it is usual to connect the heater to a source of electrical current by a plug and socket connection.

In bad weather on construction jobs, or in shipyard welding, a great amount of debris accumulates and the worker, when finished with use of the heater, usually disconnects the plug and socket and haphazardly deposits the heater in any convenient place until its use is again required. Unfortunately, the socket, usually carried by the heater, has debris accumulated therein, and subsequent connection of the plug may be prevented, or a dangerous short-circuiting condition may be established.

My invention eliminates the difficulties encountered and dangers created by debris accumulation and provides a socket which may be easily dismantled for cleaning. This, and other advantages will be apparent from the following description.

In the drawing accompanying this specification and forming a part of this application, there is shown, for purposes of illustration, several forms which my invention may assume, and in this drawing:

FIGURE 1 is a perspective view showing the plug and socket of my invention in disassembled condition,

FIGURE 2 is an enlarged longitudinal view taken through the socket,

FIGURE 3 is a plan view looking into the open end of the socket, and

FIGURE 4 is a fragmentary sectional view illustrating another form of my invention.

Referring particularly to FIGURES 1 through 3, the invention therein disclosed comprises a plug 1% and socket 11, the former being insertable into the latter to complete an electrical circuit in known manner. The plug has a cylindrical dielectric portion 12 and a pair of female terminals there-within, these terminals not being disclosed since they are of standard design. The terminals are electrically connected to a power cable 14 which may lead from a suitable power line.

The plug has a pair of openings 15-15 in its end to receive male terminals carried by socket 11. The plug and socket herein illustrated are of the twist-lock type and therefore the openings 15 are curved, as shown. However, the plug and socket may be of the push-pull type, in which case the openings would be straight to receive flat male terminals.

The socket 11 comprises a shell 16 which may be formed of any suitable material, preferably a metal such as steel. The shell is preferably cup-shaped, as seen in FIGURE 2. An electric heating element 17 is carried by the shell 16 and has a terminal portion entering the closed end of the shell.

The heating element is preferably of the type having a tubular metal sheath 18 in which is longitudinally disposed a heating resistor 19 in the form of a coil of resistance wire. Suitable heat-conducting electrical insulating material, such as powdered granular refractory mai atented Jan. 26, 15355 terial 20, compacted to a dense stone-like condition, maintains the resistor spaced from the metal sheath.

The heating element illustrated is of the hairpin type, providing a bight portion 21 and a pair of legs 22-22 disposed in generally parallel side-by-side relation. In accordance with usual construction, opposite ends of the resistor 19 are mechanically and electrically connected to terminal pins 23 23 which project outwardly of the opposite ends of the heater, as seen in FIGURE 2.

The ends of the heater pass through a pair of openings 2-i24 in the bottom wall 25 of the shell 16 and preferably a fused connection, such as a silver brazed joint 26, holds the heater end to the bottom wall for rigidity of connection and to seal the openings 24 against passage of deleterious matter therethrough.

Referring again to FiGURE 2, each terminal pin 23 has a metallic sleeve 27 of good conducting material secured to it and extending axially therefrom. A crimping of the sleeve about its terminal pin may be suificient connection, although it is preferred at the present time to secure the sleeve to its terminal pin by a heliarc weld. Each sleeve 27 has a screw-threaded opening entering from its free end to receive the threaded shank 28 of a machine screw.

The refractory material 2%), or other insulation at the ends of the heater legs 2222, is preferably stopped short of filling the leg end, to provide a cavity 29. An insulating material so is deposited within the shell at its closed end. Preferably, the material 35 is of the type which may be poured into the shell to settle on and above the bottom wall 25' and to fill the cavities 29 and all voids around the adjacent leg ends, terminal pins and lower ends of the sleeves 27. The material 30 should have good adherence to the metal parts so as to seal the parts im mersed in it against moisture and other foreign matter.

An epoxy resin has been found suitable for this purpose.

A dielectric body 31 is removably disposed within the shell 16, and this body carries the male electrical connectors. The body is in the form of a hard rubber disc which extends crosswise of the shell 16. One side 32 of the disc is directed toward the bottom wall 25 of the shell and its opposite side 33 is directed toward the open end of the shell. A circular rim 34 may extend upwardly from the side 33 to protect the connectors against electrical contact with the shell side wall.

The disc 31 is formed with a pair of openings 35 to closely pass respective sleeves 27. Each male connector as has a fiat base portion 37 overlying the disc side 33 and firmly held thereagainst in any suitable manner, such as by means of a tubular rivet 38 as in ordinary constructions. The base portion 37 of each male connector is formed with an opening 39 to freely pass the shank 23 of the machine screws.

With the machine screws fully threaded into respective sleeves 27, the screw heads 40 firmly bear against male connector base portions 37 and thus maintain the dielectric body 31 and male connectors in proper position within the shell 16. In the event debris has accumulated within the shell, it is only necessary to remove the machine screws, whereby the dielectric body 31 may be withdrawn from the shell, such as by grasping the male connectors 36 and pulling the body 31 from the shell. The body 31 and male connector parts may be washed and cleaned, and separately the interior of the shell 16 may also be I washed and cleaned, the epoxy resin 30 protecting the heater ends from moisture and debris. Thereafter, the body may be replaced within the shell and the machine screws tightened to again effect the proper assembly.

In modification shown in FIGURE 4, the sleeves 27 are omitted and the terminal pins 23a extend through the openings 35a and base portions 37a, respectively. A

and

nut is threaded on the threaded extremity of each ter minal pin ZSato effect the assembly.

In view of the foregoing it will be apparent to those skilled in the art that l have accomplished at least the principal object of my invention and it will also be apparent to those skilled in the art that the embodiments her 'n described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described; hence-it will be appreciated that the herein disclosed embodiments are illustrative only, and that my invention is not limited thereto.

1 claim:

1. An electric heater, comprising a sheathed electric heating element, a plug and socket connector for said heating element, including a cup-shaped shell forming the socket and adapted to receive said plug through the open end thereof, said heating element being connected to said shell and having an end extending through an. opening in the closed end of said shell and further having a terminal pin extending longitudinally within said 7 shell, a disc-like dielectric body removably positioned 'within said shell and having one side directed toward the closed end of said shell and an opposite sidedirected toward open end of said shell, a male electrical connector member carried by said body and adapted tobe electrically connected to a female electrical connector member carried by said plug when the latter is inserted into said shell open end, said rnaleco'nnector member having a portion overlying such opposite side of said body, a metal sleeve receiving and mechanically and electrically secured to said terminal pin, said body having an opening for passing said sleeve, and a capscrew threaded into said sleeve and having its head bearing against said male connector portion.

2. An electric heater, comprising a'sheathed electric heating element, a plug and socket connector for said heating element, including a metal cup-shaped shell forming the socket and adapted to receive said plug through the openend thereof, said heating element having an end positioned-through an opening in the closed end of said shell and having a fused connection with the shell closed end to seal said opening, said element also having a terminal pin extending longitudinally within said shell, a disc-like dielectric body removably positioned within said shell and having one side directed toward the closed end of said shell and an opposite side directed toward the open end of said shell, a male connector member carried by said body and adapted to be electrically connected to a female electrical connectormember carried by said plug when the latter is inserted into said shell open end, said male connector member having a base portion overlying said opposite side of said body and rigidly connected to the latter, a metal sleeve having one end receiving and mechanically and electrically secured to said terminal pin and having an opposite internally threaded end, said body enemas having an opening therethrongh for passing said sleeve from said opposite side surface and for passing the threaded shank of a capscrew from said one side surface, the shank of said screw passing through an opening in said base portion and threaded into said sleeve opposite end with its head bearing against said base portion.

3. Tie construction according to claim 2 wherein a resinous material is disposed within said shell and adjacent to the closed end thereof and about said terminal pin and sleeve.

4. The construction according to claim 3 wherein said resinous material is introduced into said shell in pourable form and is permitted to harden.

5. An electric heater, comprising a sheat ed electric heating element, a plug and socket connector for said heating element, including a cup-shaped metal shell forming the socket and adapted to receive said plug through its open end, said heating element having a pair of legs in jxtaposed relation, the terminal ends of said legs extending into said shell through openings in the bottom of the latter and the nesting portion of said legs being disposed exteriorly of and extending from said shell, a termi 1 pin eiitending outwardly of and the end of each of said heater legs and longitudinally inwardly of said shell, insulating mate ial Within said shell at its closed end and encasing said heater leg ends to protect the same from contact with deleterious matter, a dielectric body movable to W'hin said shell through the open end trereof and to a position overlying said insulating material, said body having one side facing said insulating material and an opposite sid facing the open end of said shell, a pair of male electrical connector me ibers carried by said body, each having a blade extending from said opposite side and adapted to be connected to a female electrical.

connector member carried by said plug when the latter is inserted into said shell, each male connector member having a' base integral with its blade and overlying said opposite side of said dielectric body, and a member overlying each of said bases and electrically connecting a base to a respective terminal pin and simultaneously releasably holding said dielectric body in position within said shell.

References fired in the file of this patent UNITED STATES PATENTS 1,472,171 aynsWorth Oct. 30, 1923 1,881,881 Noble Oct. 11, 1932 1,970,149 Pugh Aug. 14, 193 2,227,159 Schnrig Dec. 31, 1940 2,245,602 Morris June 17, 1941 2,310,325 Smith Feb. 9, 1943 2,430,593 Windsor Nov. 11, 1947 2,664,548 Dec. 29, 1953 2,703,871 Woodhead Mar. 8, 1955 2,995,646 Aug. 8, 1961 3,048,805 Aug. 7, 1962

Claims

1. AN ELECTRIC HEATER, COMPRISING A SHEATHED ELECTRIC HEATING ELEMENT, A PLUG AND SOCKET CONNECTOR FOR SAID HEATING ELEMENT, INCLUDING A CUP-SHAPED SHELL FORMING THE SOCKET AND ADAPTED TO RECEIVE SAID PLUG THROUGH THE OPEN END THEREOF, SAID HEATING ELEMENT BEING CONNECTED TO SAID SHELL AND HAVING AN END EXTENDING THROUGH AN OPENING IN THE CLOSED END OF SAID SHELL AND FURTHER HAVING A TERMINAL PIN EXTENDING LONGITUDINALLY WITHIN SAID SHELL, A DISC-LIKE DIELECTRIC BODY REMOVABLY POSITIONED WITHIN SAID SHELL AND HAVING ONE SIDE DIRECTED TOWARD THE CLOSED END OF SAID SHELL AND AN OPPOSITE SIDE DIRECTED TOWARD THE OPEN END OF SAID SHELL, A MALE ELECTRICAL CONNECTOR MEMBER CARRIED BY SAID BODY AND ADAPTED TO BE ELECTRICALLY CONNECTED TO A FEMALE ELECTRICAL CONNECTOR MEMBER CARRIED BY SAID PLUG WHEN THE LATTER IS INSERTED INTO SAID SHELL OPEN END, SAID MALE CONNECTOR MEMBER HAVING A PORTION OVERLYING SUCH OPPOSITE SIDE OF SAID BODY, A METAL SLEEVE RECEIVING AND MECHANICALLY AND ELECTRICALLY SECURED TO SAID TERMINAL PIN, SAID BODY HAVING AN OPENING FOR PASSING SAID SLEEVE, AND A CAPSCREW THREADED INTO SAID SLEEVE AND HAVING ITS HEAD BEARING AGAINST SAID MALE CONNECTOR PORTION.