US2188789A - Terminal block - Google Patents

Description

Jan. 30,1940. D. G. KI MBALL 2,138,789

TERMINAL BLOCK Filed July 21, 1938 Inventor: Donald G. Kim all,

by W 7 His Attorney.

. Patented Jan. 30, 1940 UNITED" STATES PATENT. OFFICE j TERMINAL BLOCK Donald G. Kimball, Stratford, 001111., assignor to General Electric C New York Application July 21, I 4 Claims.

I In the accompanying drawing, Fig. 1 is a view I 10 looking at the top of the terminal block; Fig. 2'

is a'sectional view on the line 2-2 of Fig. 1; Fig. 3 is aplan view looking atthe base of the block with a portion of the base closure removed;

Fig. 4 is a-sectional View on the line ll of Fig. 3

15 Fig. 5 is an exploded view of the terminal contact structure; and Fig. 6 is a sectional view through the terminal block similar to Fig. 2 showing a prong connector inserted in the terminal structure.

It is desirable in many electric ranges to provide oven heating elements which are removable to facilitate cleaning of the oven and in single 'unit ovens to provide means for changing the position of the unit to give proper heat distribug'g tion for various cooking operations such as baking. broiling, etc. To make the'heat'er elements easily removable they are provided with connectors or terminal prongs which are plugged into a terminal block placed in the oven, usually 30 in the rear wall thereof. v This invention relates to such terminal blocks which are adapted for oven mounting, Such a block must be capable of supporting an end of the heater element and, at the same time, provision must be made for u a firm electrical contact between the heater connector prongs and contact elements of the terminal block.

' Referring to the drawing, a terminal block is shown provided with a housing Ill having a' base portion H and an extended portion I 2. For the purposes of illustration, the base portion is shown ot a generally rectangular shape and is provided with holes 13 at each of the corners for mounting 'the housing upon a supporting plate such as the rear wall of an oven. In order that the terminal block may withstand the high temperatures existing in an oven the housing is made of a vitreous or ceramic material, such as porcelain. The extended portion 62 is of generally oblong form, as shown in Figs. 1 and 4. and is provided with a tapered recess 14 which merges with a plurality of contact-receiving chambers 15. In

the form of the invention il.lustrated, three of the '-chambers are provided, each being separated 23 from the other by a partition I5 integral with -D y, a corporation of 193 Serial No. 220.523

(Cl. ire-flees) the housing. 'I he number of chambers and'tere minal contacts may be increased or decreased at will depending on the number of resistor con- I nectors employed in the heating units. The base of the housing is provided with a slot II for receiving parts of the terminal contact structures now to be described;

v The terminal contact structures in each of the chambers are identical so that only one of the structures will be described. The terminal contact structure comprises a substantially L-shaped contact member l8 having a leg l9 and an arm 20 extending at right angles to the leg it. The leg mp1s provided with anfindented portion 2| having a slot 22 therein formed with a positioning edge 22a. The arm is provided with an indented portion 23 which serves as the contact surface, cooperating with a connector prong. A second contact member 2-3 cooperates with the arm 20 to form 2. prong clamping means. The contact member 24 is provided with a tang 25 whichextends into the slot 22 and permits the member 2i to move relative to the arm 26 while,

at the same time, the cooperating tang and slot v guide the movable member 24- for movement parallel: with the armzil. In normal position the tang abuts the edge 22a so that the tang endof the member 24 is spaced from the contact portion 23. This position is shown at 25', in Fig. 2. In v cross-section. A terminal screw 28 is threaded intoan opening 39 in the leg 9 for the'purpose v of, receiving the conducting lead wire.

The contact structures are mounted in the I housing in the position shown by Fig. 2. In this position the contact members l8 and 24 are disposedin the housing with the arm 29 and the .member 24 within the chamber l5 and the leg l resting in the slot 81. A heavy closure plate 3|, which may be made of insulating material such as sheet laminated materials, or the like, retains all the contact structures within the housing by extending across the slot l! and clamping the legs [9 against the base of the housing. The plate 3! is secured to the base by any suitable means such as the screws 32 seated in slots 33 formed in opposite ends of the base. The plate forms a closure for each of the chambers l5 and comprises a simple and effective means of retaining the contact structure within their respective chambers. In mounted position,

the terminal screwsZQ extend into recesses 34.

formed in the base of the housing.

In order to maintain the contact member 24 in engagement with the contact arm 2%] a resilient U-shaped spring 35 is inserted within the chamber l5 between the contact member 24 and a wall of the chamber. The ends 36 of the spring engage the ends of the member 24 while the base 31 of the spring engages the side wall of the chamber IS. The spring is made of spring steel that will withstand the high even temperatures without losing strength and resiliency.

As shown more particularly by Fig. 6, the con-; tact member 24 floats freely within the chamber l5 and moves bodily relative to the arm when-' ever a connector prong, such as shown at 38, is

inserted into the terminal contact structure. In-I sertion of the terminal prong depresses the spring 35 which in turn exerts-a strong clamping action on the contact member 24 holding the prongsecurely between the member 24 and the arm 20. In those cases where a flat connector prong is employed the flat surfaces 23 and 24a2b grip the prong firmly, whereas in those cases where a round connector prong is used the prong rests within the groove 28 and abuts the contact sur-..

face 23. Fig. 6 shows a round connector inserted in the contact assembly. In .each case the connector prong makes contact along the entire length of the indented portion 23 of'the-a'r'm 20,

thereby obtaining an excellent electrical connection between the prong and the contact structure. The slot 22 permits the contact arm 24 to move parallel to the arm 2G with the tang mov ing in the space formed between theindented portion 2| and the closure plate 3|.

The contact member .24 is of such length and so placed that easy insertion of the connector prong is possible. Due to the fact that the tang end of the contact member is normally spaced slightly from the contact arm 23, as shown at 25 in Fig. 2, it is possible to insert the connector prong without binding of the contact member which might make separation of the contact member and arm difficult. Were the tang end of the member 24 in flush contact with the surface of the chamber i5 while the edge of the indentation 2| makes contact with the opposite wall, as shown at to in Fig. 2'. By this arrangement, the

L-shaped member is held rigidly within the chamber 55 making it possible for the spring to be compressed to its fullest extent by insertion of .a connector prong so that a strong clamping action is maintained between the prong and contact structure. The contact arm 24 is prevented from falling out of the chamber 15 by the flared portion 26 which engages a leading edge 4| in the wall of the chamber. The Width of the contact structure is applicable to other terminal blocks members is substantially that of the chamber 15 so that the contact members fit snugly within the chamber at all times. v

By the terminal block construction described,

it is possible to providean adequate support for ends of. the heater elements and an'excellent electrical prongs and the contact terminal structure. The plug structure 39, shown by Fig. 6, is taperedso that it cooperates With the tapered recess l l to sup-port one end of the heater element upon the block,- while the prong is in parallel line contact Withthe contact members 20 and 24 to provide an ample area or" electrical contact; Iipping of the contact member 26 is prevented by the .L lshaped spring, the ends of which engage each end of the contact member to hold it flat against the connect-or prong. By providing a freely floating contact member, such as the contact member 24,

in cooperation with the fixed contact arm 28, it is 2 possible to make the contact members of heavy brass construction thereby insuring a strong and highly effective electrical connection; this would not be possible, were it necessary to provide resilient contacts which would flex upon insertion 2.

of theconnector prong.

The contact structures are easily assembled within the chambers I5 and the closure plate is simply bolted to the base to hold the assembled structures in position. 5 1

While the contact structure has been illustrated and described as part of an oven terminal block, it should be understood that the contact and other plug receptacles.

What I claim as new and desire to secure Letters'Pa'tent of the United States is;

1. In a terminal block structure, a housing having a chamber therein, a fixed contact, saidcontact having a contact arm within said chamber,

and a leg extending at right angles to saidarm', said leg being provided with .an extendedportion' having a slot therein, a freely floating contact member within said chamber having a tang extending into said slot, and spring means said contact member and a wall of said chamber biasing said contact member toward said contact arm. v I

2. In a device of the class described, a housing having a chamber therein, a stationary L- connection between .the connector between shaped contact having a contact arm within said chamber and a leg extending at right angles to said arm, said leg being provided with an indented portion having a slot therein, a contact member within said chamber having a tangex- $5 tending. within said slot and a -U-shaped spring having ends engaging the. ends of said member and biasing said member toward, said. contact arm, said spring maintaining said contactmeme.

ber parallel to said arm to provide a large 6gp gripping area for a connector prong.

3.1m a terminal block structure, a housing having a chamber thereirna fixed contact, said contact having a contact arm within'saidchamher and a leg extending at right angles to said ,55

am, Said leg sprovided with an extended portion having a slot therein, a freely floating contact member within said member having a tang extending into said slot, spring means between said contact member and the wall of said ,7 chamber biasing said contact member toward said contact arm, and a plate of insulating ma- .terialclosing one end of said chamber and clamp-- to retain said ing said leg against said housing assembled contacts in position.

4. In a device vof the class described, a housing having a chamber therein, a fixed contact, said contact having a contact arm within said chamber and a leg extending substantially at right angles to said arm, said legbeing provided with an indented portion having a slot'therein, a freely floating contact member within said chamber having an end extending into said slot and engaging the edge of said slot to space said end of the contact member from said arm, means between said contact member and a wall of said chamber biasing said contact member toward said contact armand a plate of insulating material closing one end of said chamber and clamping said leg against said housing to retain said assembled contacts in position, the end of said floating contact member resting in the space between said plate and indented portion.

DONALD G. ICIMBALL.

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