US3594709A

US3594709A - Electric series terminal

Info

Publication number: US3594709A
Application number: US783020A
Authority: US
Inventors: Hans Woertz
Original assignee: MESSRS OSKAR WOERTZ INH H AND O
Current assignee: MESSRS OSKAR WOERTZ INH H AND O
Priority date: 1968-02-13
Filing date: 1968-12-11
Publication date: 1971-07-20
Anticipated expiration: 1988-07-20
Also published as: GB1254304A; CH469373A

Abstract

An electric series terminal having a releasable and insertable isolating plug with an insulated grip portion and a metallic contact portion. The plug has two connecting devices for electric conductors and the terminal itself comprises an insulating body with various contacting parts therein.

Description

i United States Patent Inventor Appl. No.

Filed Patented Assignee Priority ELECTRIC SERIES TERMINAL Hans Woertz uasdyswiuefland 193,195,196, 206, 20 210, 6,153 783320 [56] 7 References Cited a; 3' 3;? UNITED STATES PATENTS 1011,639 12/1911 Murray etal. 339/19X Messrs. Oskar Woe lnh. H. 8.- woeflz "Z, 1,363,224 12/ 1920 Birch 339/19 X Basel, Switzerland FOREIGN PATENTS F21 13,1968 1,370,109 7/1964 France 339/198 (.41) graz g a Primary Examiner-Marvin A. Champion Assistant ExaminerRobert A. Hafer A!t0rneyWatson, Cole, Grindle & Watson 8 Chums Drawing ABSTRACT: An electric series terminal having a releasable US. Cl 339/198, and in nable i olating lug with an insulated grip portion and l 196 a metallic contact portion. The plug has two connecting Iiiv H01! devices for electric conductors and the terminal itself com- Fleld of Search 339/ 19, prises an insulating body with various contacting parts therein.

This invention relates to an electric series terminal with a releasably insertable isolating plug.

. It is an object of the present invention to provide an electric series terminal with a releasably insertable isolating plug having an insulated grip portion and a metallic contact portion, which'latter portion interconnects two connecting devices for electric conductors and these devices are arranged in an insulating body.

in a known series terminal of the stated type, the contact portion of the isolating plug comprises two pairs of fingers, disposed parallel with each other and each of which, for the purpose of connecting the two connecting devices, resiliently embraces a projecting contact part of said devices, the areas of contact between the plug fingers and the contact part being relatively small. Thus, in the case of heavy currents, rather severe heating can occur.

A further object of the present invention basically consists in avoiding the above-mentioned disadvantages. For this purpose, the series terminal of the invention is essentially characterized in that each of the connecting devices comprises an angular contact part with one limb of one contact part being disposed at a distance from and parallel to the corresponding limb of the other contact part. The faces of the two parallel limbs of the contact parts facing away from each other lying against the insulating body, and such faces of the two stated limbs facing each other being in contact with corresponding opposed faces on the contact portion of the inserted isolating plug.

Further objects and details of the invention will be apparent from the following description of one embodiment when considered in connection with the accompanying drawing in which:

FIG. 1 is a side elevation, partly in section, of a series terminal, the cap of the insulating body being removed;

FIG. 2 is a side view taken in the arrow direction ll of FIG. 1;

HO. 3 is a cross section taken on the line lll-lll of FIG. 1 in the direction of the arrows;

FIG. 4 is a side view of the isolating plug; and

P16. 5 is a side view of the inside of the cap of the insulating body.

As shown in the drawing, the series terminal comprises a two-part insulating body 10, a relatively small cap 13 being completely sunk or depressed into a complementary recess 11 in the larger part 12 of the insulating body, which part 12 will be referred to hereinafter as the base. Inserted in the base 12 are two connecting devices 14, in which the ends of electric conductors can be firmly clamped. Each connecting device 14 incorporates a clamping element 15, which consists of a piece or section of rectangular tube displaceably mounted in the base 12. Positioned in the tub is one limb 16 of a contact part 17 bent at right angles and this limb acts as a pressure element. The other limb 18 of the contact part 17 runs parallel with the direction in which the clamping element is displaced. As can be seen from FIG. I, the two limbs 18 of the contact parts 17 are disposed parallel with each other, and portions of the limbs 16, acting as pressure elements, are coaxial in the longitudinal direction. Each contact device 14 also incorporates a socket-hand screw 19,. which is screwed into a tapped hole in the clamping element 15 and bears with its end on the middle portion of the limb 16 of the contact part. Since the head of the screw 19 bears against a shoulder 20 in a recess 21 in the base 12, provided for turning the screw 19, and the contact part 17 is held against displacement in the base 12 in a manner to be described, the effect of turning the screw 19 is to displace the clamping element 15 relatively to the limb 16. To increase the clamping action on the conductors to be held in the connecting devices 14, that side of the limb 16 remote from the end of the screw 19 has a longitudinal groove 22. F urthermore, for the same purpose, a saddle shaped spring element 75 23 with angled end portions is fitted in the conductor-receiving compartment of each clamping element 15.

For electrically connecting the limbs 18, there is provided a isolating plug 24, FlGS. 1 and 4, which comprises an insulated grip portion and a one-piece bifurcated contact portion having two plug pins 26, which are in spaced-apart parallel relationship and are of rectangular cross section. The contact portion of the isolating plug 24 is pressed into its grip portion 25 and the plug pins 26 are spread slightly, HO. 4, when the isolating plug 24 is withdrawn from the insulating body 10.

The longitudinal grooves 22 in the shanks 16 of the contact parts 17, acting as pressure elements or surfaces are continued into the mutually facing sides of the parallel limbs 18 and over the entire length thereof, and such lateral faces of the plug pins 26 of the inserted isolating plug 24 that face away from each other, extend partially into the continued grooves and are in contact with the bottoms thereof. As can be seen from FIG. 3, except for the grooved longitudinal face portions of the parallel limbs 18 with which the plug pins 26 are in contact, all the other longitudinal face portions bearagainst walls of complimentary recesses in the insulating body 10.

Grooves

27 and 28, matched to the cross section and length of the shanks 18, are provided both in the base 12 and in the cap 13, so that both the base 12 and the cap 13 each embrace about one-half of those faces of the parallel limbs 18 of the contact parts 17 that face away from each other. Since the lengths of the above-mentioned

grooves

27 and 28 correspond to the lengths of the limbs 18 and, in addition, the ends of the limbs 16 each abut against a nose 29 on the base 12, displacement or twisting of the contact parts 17, relatively to the base 12 or the cap 13, is precluded.

The cap 13 also incorporates between the parallel limbs 18 of the contact part, a longitudinal rib 30 against which those faces of the plug pins 26 that face each other, bear. The iongitudinal rib 30 on the cap 13 engages in a complimentary groove 31 in the base 12.

In the present embodiment, the base 12 and the cap 13 are made of a thermoplastic synthetic material. The two parts of the insulating body can therefore be interconnected by molding. For this purpose, the tongue like lower end portion of the cap 13 is provided with an orifice 32 through which is pushed a cylindrical stud 33 on the base 12. The end of the stub 33 is welded to the cap 13 by the application of heat and pressure.

To prevent the plug pins 26 from being inadvertently contacted when the isolating plug 24 is being inserted or withdrawn, the grip portion 25 incorporates sleeves 34 each of which surrounds the upper end of pins plug pin 26. When the isolating plug 24 is inserted, the two sleeves 34 are fully engaged in a complimentary recess 35 in the base 12.

The important advantage of the above-described series terminal and releasably insertable isolating plug resides in the fact that the contact surfaces of the plug pins are of large area and are in contact with the corresponding opposed faces of the contact parts under relatively high pressure. The contact resistance at the 'points of contact is thereby kept small, so that even under heavy current loading, no impermissibly great heating occurs. The high contact pressure is achieved by the longitudinal faces of the parallel limbs of the contact parts lying against the walls of the insulating body and by the spreading action of the plug pins being reinforced by the longitudinal rib 30 on the cap-l3.

When the isolating plug is withdrawn, the longitudinal rib 30, disposed between the parallel limbs of the contact parts, considerably increases the creepage path distance between the contact parts. Furthermore, the cap 13 which embraces the parallel limbs of the contact parts on those of their longitudinal faces turned away from each other, counteracts deflection of the base l2 resulting from the contact pressure of the isolating plug, and in addition, due to the cap 13 being connected to the base- 12, the metal parts of the connection devices 14 are held firmly in the insulating body in a manner that prevents their being lost.

In a modified form of the series terminal, not illustrated in the drawing, the shanks l6 and 18 of the contact parts do not contain longitudinal grooves for centering the electric conductors or for guiding the plug pins 26. Despite this simplification, the good contact properties are retained, since the plug pins cannot deflect laterally. Furthermore, the cap 13 can be connected to the base 12 by gluing instead of welding.

lclaim:

1. Electric series terminal with a releasably insertable isolating plug, comprising an insulated grip portion and a metallic contact portion, said metallic contact portion interconnecting two connecting devices for electric conductors, and insulating body in which the devices are arranged, each of the connecting devices comprising an angular contact part having two limbs, one limb thereof being disposed at a distance from and colinear with a corresponding limb of the other contact parts, the other two corresponding limbs being parallel and being against the insulating body, and an inserted isolated plug with those faces of the two parallel limbs facing each other being in contact with corresponding opposed faces on a contact portion of the inserted isolating plug, and said corresponding limbs of the contact parts engaging in complimentary grooves in the insulating body.

2. Electric series terminal with a releasably insertable isolating plug, comprising an insulated grip portion and a metallic contact portion, said metallic contact portion interconnecting two connecting devices for electric conductors, an insulating body in which the devices are arranged, each of the connecting devices comprising an angular contact part having two limbs, one limb thereof being disposed at a distance from and colinear with a corresponding limb of the other contact parts, the other two corresponding limbs being parallel and being against the insulating body, and an inserted isolating plug with those faces of the two parallel limbs facing each other being in contact with corresponding opposed faces on a contact portion of the inserted isolating plug and except for the longitudinal face portions with which the contact portion of the isolating plug is in contact, all the other longitudinal face portions of the parallel limbs of the other contact parts bear against walls of complimentary recesses in the insulating body.

3. Electric series terminal according to claim 2, in which the insulating body is composed of two parts of which one part being a cap which is completely depressed in a complimentary recess in the other part of the insulating body, and the complimentary recesses against the walls of which the parallel limbs be being present in both parts of the insulating body so that the cap partially embraces those faces of the parallel limbs of he other contact part that face away from each other.

4. Electric series terminal according to claim 2, in which the insulating body is composed of two parts of which one part being a cap which is completely depressed in a complimentary recess in the other part ofthe insulating body, and the complimentary recesses against the walls of which the parallel limbs of the other contact parts lies, being present in both parts of the insulating body so that the cap partially embraces those faces of the parallel limbs of the other contact part that face away from each other, and the cap being welded to the other part of the insulating body.

5. Electric series terminal with a releasably insertable isolating plug, comprising an insulating grip portion and a metallic contact portion, said metallic contact portion interconnecting two connecting devices for electric conductors, an insulating body in which the devices are arranged, each of the connecting devices comprising an angular contact part having two limbs, one limb thereof being disposed at a distance from and colinear with a corresponding limb of the other contact parts, the other two corresponding limbs being parallel and being against the insulting body, and an inserted isolating plug with those faces of the two parallel limbs facing each other being in contact with the corresponding opposed faces on a contact portion of the inserted isolating plug, a contact part of the isolating plug comprises two plug pins in spaced-apart parallel relationshi with each other, said plug pins being interconnected in t e insulated grip portion of the isolating plug, and the insulating body comprises a rib against which the mutually facing faces of the plug pins bear between the parallel limbs of the contact part.

6. Electric series terminal according to claim 5, in which the rib forms part of the cap disposed between the plug pins and the rib engaging in a complimentary groove in the other part of the insulating body.

7. Electric series terminal with a releasably insertable isolating plug, comprising an insulated grip portion and a metallic contact portion, said metallic contact portion interconnecting two connecting devices for electric conductors, an insulating body in which the devices are arranged, each of the connecting devices comprising an angular contact part having two limbs, one limb-thereof being disposed at a distance from and colinear with a corresponding limb of the other contact parts, the other two corresponding limbs being parallel and being against the insulating body, and an inserted isolating plug with those faces of the two parallel limbs facing each other being in contact with corresponding opposed faces on a contact portion of the inserted isolating plug, a contact part of the isolating plug comprises two plug pins in spaced-apart parallel relationship with each other, said plug pins being interconnected in the insulated grip portion of the isolating plug, the plug pins being of rectangular cross section, and the mutually facing sides of the parallel limbs of the contact parts containing longitudinal grooves into which the plug pins at least partially extend.

8. Electric series terminal according to claim 7, in which the longitudinal grooves in the parallel limbs of the other contact parts being continued in the other limbs thereof, which latter limbs are arranged as pressure elements, in a tubular clamping element of each connecting device.

Claims

4. Electric series terminal according to claim 2, in which the insulating bOdy is composed of two parts of which one part being a cap which is completely depressed in a complimentary recess in the other part of the insulating body, and the complimentary recesses against the walls of which the parallel limbs of the other contact parts lies, being present in both parts of the insulating body so that the cap partially embraces those faces of the parallel limbs of the other contact part that face away from each other, and the cap being welded to the other part of the insulating body.

5. Electric series terminal with a releasably insertable isolating plug, comprising an insulating grip portion and a metallic contact portion, said metallic contact portion interconnecting two connecting devices for electric conductors, an insulating body in which the devices are arranged, each of the connecting devices comprising an angular contact part having two limbs, one limb thereof being disposed at a distance from and colinear with a corresponding limb of the other contact parts, the other two corresponding limbs being parallel and being against the insulting body, and an inserted isolating plug with those faces of the two parallel limbs facing each other being in contact with the corresponding opposed faces on a contact portion of the inserted isolating plug, a contact part of the isolating plug comprises two plug pins in spaced-apart parallel relationship with each other, said plug pins being interconnected in the insulated grip portion of the isolating plug, and the insulating body comprises a rib against which the mutually facing faces of the plug pins bear between the parallel limbs of the contact part.

7. Electric series terminal with a releasably insertable isolating plug, comprising an insulated grip portion and a metallic contact portion, said metallic contact portion interconnecting two connecting devices for electric conductors, an insulating body in which the devices are arranged, each of the connecting devices comprising an angular contact part having two limbs, one limb thereof being disposed at a distance from and colinear with a corresponding limb of the other contact parts, the other two corresponding limbs being parallel and being against the insulating body, and an inserted isolating plug with those faces of the two parallel limbs facing each other being in contact with corresponding opposed faces on a contact portion of the inserted isolating plug, a contact part of the isolating plug comprises two plug pins in spaced-apart parallel relationship with each other, said plug pins being interconnected in the insulated grip portion of the isolating plug, the plug pins being of rectangular cross section, and the mutually facing sides of the parallel limbs of the contact parts containing longitudinal grooves into which the plug pins at least partially extend.