US3265863A

US3265863A - Heater with terminal mount

Info

Publication number: US3265863A
Application number: US329792A
Authority: US
Inventors: Joseph A Bender
Original assignee: Vacuum Die Casting Corp
Current assignee: Vacuum Die Casting Corp
Priority date: 1963-12-11
Filing date: 1963-12-11
Publication date: 1966-08-09
Anticipated expiration: 1983-08-09

Description

9, 1,966 J. A. BENDER 3,265,863

, HEATER WITH TERMINAL MOUNT Filed Dec. 11, 1963 2 Sheets-Sheet 1 INVENTOR. .7060 A. 554 00? J. A. BENDER HEATER WITH TERMINAL MOUNT Aug. 9, 1966 Filed Dec. 11; 1963 2 Sheets-Sheet 2 INVENTOR. JOJEPH A. es/v05? United States Patent 3,265,863 HEATER WITH TERMINAL MOUNT Joseph A. Bender, Springfield, N.J., assignor to Vacuum Die lasting Corp., Newark, N.J., a corporation of Ghio Filed Dec. 11, 1963, Ser. No. 329,792 18 Claims. (Cl. 213-481) This invention relates to appliances using a rod-type heater, and having terminals to receive the plug of a power supply cord.

Many electrical appliances employ a so-called rodtype heater, this comprising a resistor insulatedly housed in a stiff metal sheath. A common example is a coffee percolator in which the cup or well at the bottom of the pot has a rod-type heater coiled therearound when the cup is made of sheet metal, or embedded therein when the cup is cast. The appliance further includes an insulation block having adjacent parallel terminal pins which slida-bly receive the plug of an ordinary flexible power supply cord. Because of the provision of control means such as a thermostatic switch, and additional refinements such as an auxiliary heater to keep the coffee warm after it has been brewed, it is not-feasible to mount the insulation block directly on the two ends of the rod-type heater, and instead it has heretofore been separately mounted. Welded wiring then has been used to connect the terminal pins to the heater and thermostat.

The general object of the present invention is to reduce the cost of manufacture of such appliances, and to improve the same. A more specific object is to eliminate the need for a separate mounting of the terminal block in the appliance. Another object is to reduce the wiring needed between the terminal block and the heater.

To accomplish the foregoing general objects, and other more specific objects which will hereinafter appear, my invention resides in the heater and terminal elements and their relation one to another, as are hereinafter more particularly described in the following specification. The specification is accompanied by drawings in which:

FIG. 1 is a plan View of a die cast heater cup embodying features of the invention;

FIG. 2 is a vertical section taken approximately in the plane of the stepped line 2-2 of FIG. 1;

FIG. 3 is a vertical section through the lower portion of a coffee percolator provided ,with the heater shown in FIGS. 1 and 2;

FIG. 4 is a horizontal bottom view taken approximately in the plane of the line 4 -4 of FIG. 3;

FIG. 5 is a bottom view like FIG. 4, but showing a modification with a disc-type thermostat;

FIGS. 6 and 7 are electricaldiagrams showing two ways to wire the appliance; and

FIGS. 8 and 9 show a modified detail.

Referring to the drawings, and more particularly to FIGS. 3 and 4, the particular electrical appliance here illustrated is a coffee percolator. It comprises a pot 12 having a bottom 14, and fixed over a base 16 by any suitable means, not shown. A heater cup 20 is secured beneath bottom 14, as by means of a threaded neck 22, and a nut 24 tightened over a suitable gasket to prevent leakage. The tube 26 leads upward to and forms a part of the cofiee basket. The latter has a removable spreader disc. These parts are not shown, and are located as usual near the top of the pot.

The present percolator includes an auxiliary heater 36 (FIG. 4) which may be used to keep the coffee warm after it has been brewed, the power to the main heater being reduced by means of a thermostatically control-led switch 32. The auxiliary heater 30 may be wired to act as a control resistor in series with the main heater.

Electricity is supplied to the appliance by means of a 3,255,853 Patented August 9, 1966 conventional flexible supply cord terminating at one end in a plug, suggested in broken lines at 34 in FIG. 4. Plug 34 is slidably received over terminal pins 36 and 38, these. being fixedly carried by an insulation block 40. The plug 34 preferably fits the pins 36, 38 snugly,

in order to provide a good low-resistance electrical contact. Because many people are in a hurry, or are careless, the insertion and removal of the plug may be done roughly, and the terminal block 40 therefore must be mounted very securely in the appliance. This heretofore added substantially to the cost of manufacture when the block 40 was separately mounted in the appliance.

The new heater assembly may be described with reference to FIGS. 1 and 2 of the drawing. There is a rod-type heater element 42 which comprises a resistor in a stiff tubular metal sheath, the tubular space and resistor coil being packed with insulation material. The sheath of the heater element has remotely spaced ends 44 and 46 (FIG. 1). The insulation terminal block 40 has terminal pins 36 and 38. The block 40 is fixedly mounted on the end 44 of the sheath, with pin 38 electrically connected directly to the adjacent end of the resistor. The usual projecting wire for electrical connection to the other end of the resistor is shown at 48. The rod-type heater usually has such a center projection at each end. The rear end of terminal pin 36 is exposed at 50* behind the block 40 to receive a wire connection. This usually runs to some form of control element or switch, and thence to the other end 48 of the resistor.

Described in somewhat different fashion, it may be said that the insulation block 40 is fixedly mounted on the heater assembly at one end of the rod-type heater. This avoids the need for a separate mounting of the insulation block, and it also avoids the need for special external or exposed electrical wiring between the pin 38 and one end of the resistor.

The particular heater assembly here shown comprises a die cast cup 52 which is cast directly around the rodtype element 42, the latter being preliminarily coiled and having it ends 44 and 46 projecting in different directions from the cup. In the present case, the ends project approximately at right angles. The block 40 is made of a suitable insulation material, preferably a ceramic material such as steatite. It is secured directly around the outside of the projecting sheath 44, as by use of a refractory non-conductive cement, one example being that commercially known as Sauereisen."

While not essential, in preferred form the die cast cup includes a key 54 projecting outwardly therefrom, and the insulation block 40 has a mating slot 56 which receives the key in order to help lock the block in position. More specifically it helps lock it against rotation about the sheath end 44. The key could be on the block and the slot in the die casting, but the illustrated arrangement is preferred.

The heater assembly 20, as die cast, preferably includes outwardly projectingsupports 60 which serve to retain the auxiliary heater 30 (FIG. 3) in position against the bottom 14 of the pot.

The upper .portion of the cup 22 (FIG. 2) is externally threaded to receive a nut which secures the heater in position.

Reverting to FIG. 4, in the present case the auxiliary heater 30 is a loop terminating at 62 and 64. The bimetal leaf-type thermostat 32 has terminals which receive the connections at 62 and 64. To complete the wiring of the appliance a conductor 66 is run from terminal 64 to the resistor terminal 48 of the main heater, and another conductor 68 is run from terminal 62 to the rearwardly projecting pin 50. The

conductors

66 and 68 are preferably stiff and may be bare. Conductor 68 is omitted in FIG. 3.

The equivalent electrical diagram is shown in FIG. 6, in which terminal 38 is connected directly to one end of the main heater 42. Terminal 36 is connected to switch 32, and thence to the other end of the main heater 42. When the temperature rises sufficiently, the switchopens.

In the present circuit the auxiliary heater 30 is conriected across the terminals of switch 32, and therefore controls rather than replaces the main heater 42. Resistor 30 is inoperative when the switch is closed, but becomes operative when the switch opens. The two resistors are then connected in series, with consequent reduced heating. The resistance of the auxiliary resistor 36} is selected to bring the total heat dissipation down low enough to merely keep the coffee warm. Both resistors are deenergized by pulling the plug from the terminal block.

The components may be wired differently, and an alternative method is illustrated in FIG. 7. Here agaln terminal 38'is connected directly to the main resistor 42, While terminal 36 is connected to switch 32 and thence to the resistor 42. The auxiliary heater 130 is in this case connected directly across the terminals 36, 38. It will be evident that when the switch is closed both heaters are operative. When the coffee has been brewed, switch 32 opens and only the auxiliary heater 130 is operative. Heater 130 is deenergized by pulling the plug from the percolator. i

The bimetal leaf-type thermostat shown in FIG. 4 is commonly employed when the percolator provides for adjustment of the brewing strength. For this purpose the fixed contact is somewhat movable relative to the movable contact carried by the bimetal element. The adjustment of the fixed contact is made by means of a suitable external control, not shown.

If such adjustment of the thermostat is not wanted, the switch may be a snap-action disc-type thermostat, and such an arrangement is shown in FIG. 5. Here again the terminal 38 is connected directly to one end of the main resistor. The terminal 36 is connected by a conductor 168 to the terminal 162 of a snap-action disc-type thermostat 132. The other terminal 164 of the thermostat is connected by means of a conductor 166 to the free end 48 of the main heater. Thus the operation of the main heater is controlled by the opening and closing of the switch 132.

The auxiliary heater 130 is again supported against the bottom of the pot by means of the radial supports 60. One end is connected to terminal 162, and the other end to, terminal 164. The specific arrangement here shown therefore corresponds electrically to FIG. 6; but it will be understood that the arrangement of FIG. 7 also could be employed if desired.

The auxiliary heater usually differs from and is less expensive than the main rod-type heater. It may employ a resistance wire wound about an asbestos cord and received in an insulation sheath, for example, glass tubing.

While not essential, if desired the insulation block 40 may be additionally supported by an upstanding pedestal 70 (FIG. 3). The base 16 may be made of a phenolic plastic or other such material. In any case, if the base 16 is a molded base it may be molded integrally with an upstanding pedestal 70 dimensioned to somewhat support the block 40. This is not essential because the attachment to the heater unit is ordinarily rigid enough for the present purpose, without additional support.

It will be understood that the cup may be made of drawn sheet metal, with the rod-heater coiled around it, and brazed to it. It will also be under-stood that the insulation block can be secured directly to the die cast metal or to the cup, instead of to one end of the sheath. However, it is preferred to secure it to the sheath and cold terminal of the heater.

If the cup is a drawn sheet metal cup, it is not as easy to provide a key and slot like that shown in FIG. 1 to prevent rotation of the insulation block. The cement alone is adequate, but if it be desired to provide an additional mechanical lock, or to omit the use of cement, a construction may be employed like that shown in FIGS. 8 and 9. Referring to those figures, the sheath 202 as before has a cold terminal 204 over which the hollow terminal pin 206 is slid. The base of pin 206 is made square instead of round, as shown at 208 in FIG. 9, and it is received in a mating square recess in the insulation block 214 The hollow pin 206 may be welded to the cold terminal 204, but in the present case a diiferent connection is shown. The metal is sharply indented or staked at 212, thereby locking the

parts

204 and 206 securely together against longitudinal movement and against rotation.

The other terminal pin 214 may be secured in similar fashion, that is, by staking it as shown at 216 to a terminal post 218, the latter having a flange 220.

Thus, FIGS. 8 and 9 show two variants compared to FIGS. 1 and 2, one being the use of staking instead of welding to secure the hollow terminal pin to the cold terminal of the heater, and the other being the use of a square flange 208, as a method of keying the insulation block against rotation. Either of these features may be used alone, as well as both together. Staking may be used in lieu of welding (or hard solder) in any of the illustrated forms of the invention, and the square flange to prevent rotation may be used even with a die cast cup, in

lieu of the key and slot shown in FIG. 1.

It is believed that the construction and operation of my improved heater and terminal mounting, as well as the advantages thereof, will be apparent from the foregoing detailed description. It will also be apparent that while I have shown and described the invention in several preferred forms, changes may be made without departing from the scope of the invention as sought to be defined in the following claims. In the claims, the reference in some claims to the key and slot is not intended to exclude the reverse arrangement, which would similarly interlock the 'parts, the block having the key, and the die casting having the slot, instead of vice versa as here shown.

I claim:

1. A rod-type heater comprising a resistor in a stiff sheath having two spaced ends, an insulation terminal block having two terminal pins the outer ends of which are adapted to receive the slidably detachable plug of an electrical supply cord, said block being fixedly mounted on one end of the sheath with the inner end of one of the pins electrically connected to said end of the resistor, the

2. A rod-type heater comprising a resistor in a stiff' sheath having two spaced ends, an insulation terminal block having two adjacent parallel terminal pins the outer ends of which are adapted to slidably receive the slidably detachable plug of an electrical supply cord, said block being fixedly mounted on one end of the sheath with the inner end of one of the pins in alignment with and directly electrically connected to said end of the resistor, the rear end of the other pin being spaced from the other end of the resistor and being exposed behind the block to receive a wired connection to a switch and thence to the other end of the resistor.

3. An appliance comprising a die cast portion cast directly around a rod-type heater element having its two ends spaced and projecting from the die cast portion, the rod element including a resistor in a metal sheath, an insulation terminal block having two terminal pins the outer ends of which are adapted to receive the slidably detachable plug of an electrical supply cord, said block being fixedly mounted on one projecting end of said sheath with the inner end of one of the pins in alignment with and directly connected to said end of the resistor, the inner end of the other pin being spaced from the other end of the resistor and being exposed to receive a wired connection leading to the other end of the resistor.

4. An appliance comprising a die cast portion cast directly around a rod-type heater element having its two ends spaced and projecting from the die cast portion, the rod element including a resistor in a metal sheath and having two cold terminals, an insulation terminal block having two terminal pins adapted to receive the plug of an electrical supply cord, said block being fixedly mounted on one projecting end of said sheath with one of the pins in alignment with and directly connected to the cold terminal of said end of the resistor, the die cast portion having a key projecting outwardly therefrom and the insulation block having a mating slot which receives the key in order to help lock the block against turning, the other pin being exposed to receive a wired connection leading to the other end of the resistor.

5. An appliance comprising a die cast portion cast directly around a rod-type heater element having its two ends spaced and projecting from the die cast portion, the rod element including a resistor in a metal sheath and having two cold terminals, an insulation terminal block having two terminal pins adapted to receive the plug of an electrical supply cord, said block being fixedly mounted on one projecting end of said sheath with one of the pins in alignment with and directly connected to the cold terminal of said end of the resistor, the die cast portion having a key projecting outwardly therefrom and the insulation block having a mating slot which receives the key in order to help lock the block against turning, the rear end of the other pin being exposed behind the block and having a wired connection to a switch and thence to the other end of the resistor.

6. A heater for a coffee percolator, said heater comprising a cup and a coiled rod-type heater element having its two ends projecting from the cup, the rod element including a resistor in a metal sheath, an insulation terminal block having two terminal pins the outer ends of which are adapted to receive the slidably detachable plug of an electrical supply cord, said block being fixedly mounted on the heater at one end of said rod-type element with the inner end of one of the pins directly connected to said end of the resistor, the inner end of the other pin being spaced from the other end of the resistor and being exposed for a wired connection leading to the other end of the resistor. a

7. A heater for a coffee percolator, said heater comprising a die cast cup cast directly around a coiled rod-type heater element having its two ends projecting from the die cast cup, the rod element including a resistor in a metal sheath, an insulation terminal block having two terminal pins the outer ends of which are adapted to receive the slidably detachable plug of an electrical supply cord, said block being fixedly mounted on one projecting end of said sheath with the inner end of one of the pins in alignment with and directly connected to said end of the resistor, the inner end of the other pin being spaced from the other end of the resistor and being exposed for a wired connection leading to the other end of the resistor.

8. A heater for a coffee percolator, said heater comprising a die cast cup cast directly around a coiled rodtype heater element having its two ends projecting from the die cast cup, the rod element'including .a resistor in a metal sheath, an insulation terminal block having two terminal pins adapted to receive the plug of an electrical supply cord, said block being fixedly mounted on one projecting end of said sheath with one of the pins in alignment with and directly connected to said end of the resistor, the die cast cup having a key projecting outwardly therefrom and the insulation block having .a mating slot which receives the key in order to help lock the block in position, the rear end of the other pin being exposed behind the block for a wired connection leading to the other end of the resistor.

9. A rod-type heater element having two ends, the rod ends of which are adapted to receive the slidably detachable plug of an electrical supply cord, said block being fixedly mounted on one projecting end of said sheath with the inner end of one of the pins in alignment with and directly connected to said end of the resistor, and mating means in the heater element and the block to lock the block against rotation, the inner end of the other pin being spaced from the other end of the resistor and being exposed to receive a wired connection leading to the other end of the resistor.

10. A rod-type heater element having two spaced ends, the rod element including .a resistor in a metal sheath and having cold terminals, an insulation terminal block having two adjacent parallel terminal pins the outer ends of which are adapted to slidably receive the slidably detachable plug of an electrical supply cord, said block being fixedly mounted on one projecting end of said sheath with the inner end of one of the pins in alignment with and directly connected to the cold terminal of said end of the resistor, and mating means in the heater element and the block to lock the block against rotation, the other pin having a post and said post being spaced from the other end of the resistor and being exposed behind the block to receive awired connection to a switch and thence to the other end of the resistor.

11. An appliance comprising a heater assembly made up of a die cast portion cast directly around a rod-type heater element having its two ends spaced and projecting from the die cast portion, the rod element including a resistor in a metal sheath, an insulation terminal block having two terminal pins the outer ends of which are adapted to receive the slidably detachable plug of an electrical supply cord, said block being fixedly mounted on one projecting end of said sheath with the inner end of one of the pins in alignment with and directly connected to said end of the resistor, and mating means in the heater assembly and the block to help lock the block in position, the inner end of the other pin being spaced from the other end of the resistor and being exposed to receive a wired connection leading to the other end of the resistor.

12. An appliance comprising a heater assembly made up of a die cast portion cast directly around a rod-type heater element having its two ends spaced and projecting from the die cast portion, the rod element including a resistor in a metal sheath and having cold terminals, an insulation terminal block having two adjacent parallel terminal pins the outer ends of which are adapted to slidably receive the. slidably detachable plug of an electrical supply cord, said block being fixedly mounted on one projecting end of said sheath with the innerend of one of the pins in alignment with and directly connected to the cold terminalof said end of the resistor, and mating means in the heater assembly and the block to "lock the block against-rotation, the other pin having a post and said post being spaced from the other end of the resistor .and being exposed behind the block to receive a wired connection to a switch and thence to the other end of the resistor. I

. 13. An appliance as defined in claim 1, in which the heater has a cold terminal, and in which the terminal pin is hollow and is secured to the cold terminal by being indented or staked into the cold terminal.

14. An appliance as defined in claim 10, in which the hollow terminal pin is secured to the cold terminal of the resistor by being indented or staked one into the other.

7 the non-circular flange to prevent rotation of the insulation block about the end of the heater, and in which the hollow terminal pin is secured to the cold terminal of the resistor by being indented or staked into the cold terminal.

17. A heater as defined in claim 7, in which the die cast cup has outwardly projecting supports outside the cup for supporting an auxiliary heater against the bottom of the pot, and in which a thermostatic switch is so wired to the main and auxiliary heaters as to reduce but not terminate the heating when the switch opens.

18. A heater as defined in claim 7, in which the die cast cup has a threaded upper portion designed for passage through the bottom of a percolator pot, and in which there are outwardly projecting supports outside the cup for supporting an auxiliary heater against the bottom of 1 the pot, and in which a thermostatic switch is so wired to the main and auxiliary heaters as to reduce but not terminate the heating when the switch opens.

References Cited by theExaminer UNITED STATES PATENTS Brueckmann 31325 Reynolds 33914 Baxter 339145 Ackerman 339188 Schwaneke et al. 99281 Deist 99281 X Soper et al. 219441 Temple 338274 Price 219 -441 r RICHARD M. WOOD, Primary Examiner. 0

ANTHONY BARTIS, Examiner.

V. Y. MAYEWSKY, Assistant Examiner.

Claims

1. A ROD-TYPE HEATER COMPRISING A RESISTOR IN A STIFF SHEATH HAVING TWO SPACED ENDS, AN INSULATION TERMINAL BLOCK HAVING TWO TERMINAL PINS THE OUTER ENDS OF WHICH ARE ADAPTED TO RECEIVE THE SLIDABLY DETACHABLE PLUG OF AN ELECTRICAL SUPPLY CORD, SAID BLOCK BEING FIXEDLY MOUNTED ON ONE END OF THE SHEATH WITH THE INNER OF ONE OF THE PINS ELECTRICALLY CONNECTED TO SAID END OF THE RESISTOR, THE INNER END OF THE OTHER BEING SPACED FROM THE OTHER END OF THE RESISTOR AND BEING EXPOSED TO RECEIVE A WIRED CONNECTION LEADING TO THE OTHER END OF THE RESISTOR.