US3325775A - Electrical terminal - Google Patents

Description

June 13, 1967 A. M. ZAK 3,325,775

ELECTRICAL TERMINAL Filed NOV. 8, 1965 I VENTOR. ALFRED M ZAK ATTOQNEYS United States Patent 3,325,775 ELECTRTQQJL TERll IINAL Alfred M. Zak, 611d Casrnere, Detroit, Mich. 4-8212 Filed Nov. 8, 1965, Ser. No. 566,67 3 Claims. (Cl. 339256) This invention relates to electrical connectors, and more particularly to electrical terminal blocks and terminal contacts used therewith.

In many industrial fields, for example, automotive, aircraft and appliance, the use of a great number of disconnectible electrical conductors has become very prevalent. Usually the disconnect feature takes the form of a pair of terminal blocks in which many male and female terminal contacts are arranged such that they can be telescopically engaged and disengaged. Because of space limitations in many instances, the sizes of such terminals have by necessity become progressively smaller, and the problems encountered have become correspondingly greater. As the size (the diameter) of the terminal is reduced, the sheet metal from which the terminal is fabricated is likewise reduced in thickness and with extremely thin sheet metal portions of the terminal become quite flimsy.

Even with such small diameter terminals there remains the necessity of providing a terminal construction which insures good contact between the telescoping terminal members and which at the same time enables the terminals to be solidly anchored within a terminal block, so they will not collapse or distort upon connecting or separating the terminal blocks.

it is accordingly an object of this invention to provide a terminal construction which is admirably suited for fabrication in small sizes and which at the same time is designed so that it can be solidly anchored within a terminal block.

A further object of the invention resides in the provision of a terminal which is designed such that it can be economically produced in progressive dies and after forming, a plurality of such terminals, connected to a carrier strip, can be easily handled and fed to and from a reel.

In the drawings:

FIG. 1 is a fragmentary sectional view of a pair of terminal blocks provided with male and female terminals of the present invention, the terminals being shown partly broken away.

FIG. 2 is a perspective view of the male terminal.

FIG. 3 is a sectional view taken along the line 33 of FIG. 2.

FIG. 4 is a perspective view of the female terminal.

FIG. 5 is a fragmentary sectional view showing the manner in which the terminal of the present invention can be released from within its terminal block.

FIG. 6 is a fragmentary end view of one terminal lock as viewed along the line 6-6 of FIG. 5 with the terminal removed.

In FIG. 1 a pair ofterminal blocks 16 and 12 are illustrated. As is conventional, these terminal blocks are formed of an electrical insulating material such as Bakelite. Withinblock 10 there is arranged a femaleterminal contact 14, and within block 12 there is arranged a maleterminal contact member 16. These two contacts are shown in perspective in FIGS. 4 and 2, respectively. As illustrated, both terminals are of generally cylindrical shape and are adapted to be formed from flat sheet metal in progressive dies. At their outer ends each terminal is formed with a pair oftabs 18 which are adapted to be crimped around the insulatingcoating 20 of a strandedwire conductor 22. Each terminal is also formed with a second pair oftabs 24 spaced axially fromtabs 18,tabs 24 being adapted to be crimped over the bared end of the strandedconductor 22 to provide good electrical contact between the terminal and the conductor.

Terminal 14 is formed with acylindrical body portion 26 andterminal 16 is formed with acylindrical body portion 28. The inner diameter of thebody portion 26 ofterminal 14 is dimensioned relative to the outer diameter of thebody portion 28 ofterminal 16 such that they have a slight interference fit. For example, in a terminal construction wherein the outer diameter ofbody portion 28 is about .093 inch, the nominal inner diameter ofbody portion 26 may be about .003 inch less, so that the insertion ofbody portion 28 intobody portion 26 requires a slight circumferential expansion ofbody portion 26. The sheet metal from which such terminals are formed has at least a slight degree of resilience, so that the interference fit will provide good electrical contact between the two terminals. The axially extending parting line between the contacting or near contacting longitudinal edges ofterminal 14 is indicated at 30-and the corresponding parting line onterminal 16 is indicated at 32.

Terminal block 10 is fashioned with abore 34 dimensioned to receive thecylindrical body portion 26 ofterminal 14 and acounterbore 36 dimensioned to receive the enlarged outer end ofterminal 14 at thetabs 18. These two bores are separated by ashoulder 38. Thebody portion 26 ofterminal 14 is fashioned with a pair of radially outwardly extendinglugs 44 that are adapted to abut againstshoulder 38 and thus limit movement ofterminal 38 in a direction inwardly ofblock 10, that is, in a direction toward the right in FIG. 1.

Terminal block 12 is fashioned with acylindrical socket 42 adapted to receive thecylindrical body portion 28 ofterminal 16 with a rather close fit and acounterbore 44 adapted to receive the enlarged outer end ofterminal 16 attabs 18. The junction between these two bores defines a shoulder 46 which is adapted to be engaged bylugs 48 onterminal 16 to limit the extent to whichterminal 16 can move in a direction inwardly of terminal block 12, that is, in a direction to the left as viewed in FIG. 1.

Bore 34 is formed at One side thereof with an axially extending recess orslot 50, and bore 46 is likewise formed with a longitudinally extending recess orslot 52. These slots extend to the inner end faces of the terminal blocks, as indicated at 54, which faces are adapted to be brought into abutting relation when the terminals are telescopically engaged.Slot 50 accommodates atab 56, andslot 52 accommodates atab 58. The construction and function of each of these tabs is the same, and for this'reason onlytab 56 will be described in detail.Tab 56 is struck inwardly from the wall ofbody portion 26 aboutbend line 57, and extends across the hollow interior ofbody portion 26 at an acute angle to the longitudinal axis of the terminal. At itsfree end tab 56 extends through an opening 60 inbody portion 26 which is diametrically opposite the opening 62 which results from strikingtab 56 inwardly. It will be noted thattab 56 engages theedge 64 of opening 60 so that the extent to which it can be flexed outwardly of opening 60 is effectively limited by theedge 64. Edge 64 is located so as to accurately control the extent to which the free end portion 66 oftab 56 projects radially outwardly beyond the outer periphery ofcylindrical body portion 26. As is clearly evident from FIG. 1, Whenterminal 14 is inserted in block withlugs 40engaging shoulder 38, the end portion 66 oftab 56 is spaced slightly from theend 67 ofslot 50.

Tab 58 onterminal 16 is likewise struck inwardly from thecylindrical body portion 28 aboutbend line 69 and extends across the hollow interior ofbody portion 28 at an acute angle to the longitudinal axis of the terminal With itsfree end portion 68 projecting outwardly through an opening 70 inbody portion 28.Tab 58 bears against theedge 72 of opening 70 to limit the extent to whichtab 58 can flex in a direction outwardly ofbody portion 28. Withterminal 16 fully inserted in block 12, that is, withlug 48 engaging shoulder 46, thefree end portion 68 oftab 58 is spaced slightly from theend 69 ofslot 52. In actual manufacture,tabs 56, 58 are overbent slightly so that they are preloaded, that is, they are in pressure contact with the backing edges of therespective holes 60, 70 through which they project. This eliminates entirely any problem of maintaining close tolerances in the bending of these tabs.

The leading end ofterminal 16 is preferably formed with atapered nose 74 to facilitate its insertion in theopen end 76 ofterminal 14. In addition,tapered nose 74 is fashioned with a radially extendinglug 78 which is aligned with theparting line 32 on thecylindrical body portion 28.Lug 78 is preferably bent up from one edge of the body portion and the adjacent edge is notched slightly as at 80, so that the lug will be disposed on the center line of the terminal. The leading edges ofterminal 14 are notched or tapered as at 82, to facilitate entry oflug 78 between the contacting edges which form theparting line 30 onterminal 14.Terminal 14 is also formed with anaperture 84 positioned to receivelug 78 whenterminal 16 is fully inserted interminal 14. To facilitate withdrawal ofterminal 16 fromterminal 14, the leading edges ofaperture 84 are tapered as at 86.

Each terminal is engaged within its respective terminal block by inserting the terminal through the block from the outer end thereof. In the case ofterminal 16 and block 12, for example,terminal 16 is inserted leading end foremost through the open end 87 ofbore 44. The portion of the block aligned centrally oftab slot 52 and adjacent shoulder 46 is fashioned with aradial slot 88 to accommodatelug 78. As the end oftab 58 engages shoulder 46 it is deflected inwardly in the manner of a leaf spring through opening 70 so that the tab can pass into thesmaller bore portion 42. Whentab 58 is aligned withslot 52, the tab snaps radially outwardly intoslot 52 to the extent permitted by theedge 72 of the opening 70 in the terminal. The terminal is thus effectively locked in the terminal block.Terminal 14 is engaged within itsterminal block 10 in substantially the same manner. It will be understood that normally each terminal block retains a plurality of laterally spaced terminals.

When it is desired to interconnect the terminals, terminal block 12 is manipulated relative to theterminal block 10 to align each of thenose portions 74 ofterminals 16 with theopen end 76 of a correspondingterminal 14 inblock 10. Insertion of thebody portions 28 into theterminal block 10 is facilitated by aslight chamfer 90 at the open end of thebore 34 ofterminal block 10. As the leading ends ofterminals 16 are advanced intoterminals 14, thelug 78 on each terminal 16 enters between thetapered edges 82 on thecorresponding body portion 26 to facilitate the circumferential expansion of each terminal 14 and thus separate the contacting edges forming theparting line 30.

When the juxtaposed faces 54 of the two terminal blocks come into abutting relation, each lug 78 snaps into a correspondingaperture 84 and thus causes eachbody portion 26 to contract into tight engagement with the associatedbody portion 28 ofterminals 16. To disconnect the terminals the operation is reversed, and the force required to pull them apart is lessened by the provision oflug 78 in conjunction with the taperededges 86 ofaperture 84.

It will be appreciated that where each terminal block contains many terminals, a rather substantial force may be required to telescopically engage the terminals. However, in view of the fact that thetabs 56, 58 are rigidly backed adjacent their outer ends againstedges 64, 72, respectively, there is no tendency for these tabs to collapse, even though they are of rather substantial length. Their rigidity can be increased if desired by forming them with a slight crown in cross section, as illustrated. The fact that thetabs 56, 58 are of substantial length is, however, a definitely advantageous feature of my terminal construction. Being of substantial length, they deflect rather easily and have near perfect recovery as compared to a relatively short tab which would have to bend to a substantially greater extent in order to insert the terminal in the terminal block. Even though the tabs themselves are of substantial length, nevertheless they project radially outwardly from the terminal only a slight extent. For example, on a .093 inch terminal the tab is designed to project radially beyond the cylindrical body portion only .020 inch. This contributes to their rigidity.

Likewise, by forming thetabs 56, 58 so that they extend across the hollow interior of their respective terminal, each of the terminals can be readily removed from the terminal blocks by inserting a removal tool, such as indicated at 92, through the open end of the terminal to deflect the tab inwardly to a position where it will clear the end of the slot in which it is disposed. As pointed out previously, each tab has sufiicient clearance with theinner end 67, 69 of the corresponding slot in the terminal block to enable the tab to flex radially inwardly through theopening 70 or 60, as the case may be. In the drawing the inclination oftabs 56, 58 to the axis of the terminals is illustrated as about 45. This inclination can be increased or decreased within limits but it is imortant that in any event the tab be inclined to the axis of the terminal at an angle substantially less than 90 in order to obtain the above-described advantages of my invention.

Another important feature of the present invention lies in the fact that even though the terminal may be formed of a lightweight sheet metal, for example, sheet metal having a thickness of .0126 inch in the case of a terminal having a diameter of .093 inch, the terminal itself is relatively rigid and does not have any long, flimsy radial projections on its outer surface. This is important because terminals of this type when formed on progressive dies are advantageously interconencted bylugs 94 with carrier strips 96 to enable handling of the terminals as reels. For example, until the individual terminals are crimped onto a wire, they are connected to the carrier strips orrunners 96 so that they can be reeled. The die which crimps thetabs 18 and 24 is preferably fashioned so that it simultaneously shears thelugs 94 from the opposite ends of the treminals. Since these terminals are handled as reels for purposes of convenience, it is important that the terminals have no flimsy exterior projections which would readily entangle with similar projections or the like on the terminals on the next successive convolution of the reel.

I claim:

1. An electrical connecting means comprising a pair of male and female terminal members dimensioned for snug telescopic engagement, said female member having a hollow portion provided with a pair of juxtaposed separable edges which extend axially of the terminal member, said male member having a radially extending projection adjacent one end thereof adapted to engage between said juxtaposed edges to separate them and there by circumferentially expand the hollow portion of the female member when telescopically engaged therewith, said female member having an opening in the Wall thereof contiguous to and in alignment with said juxtaposed edges -to receive said projection when the members are fully telescoped to allow said edges to return toward their free condition and thereby circumferentially close on the male member.

2. The combination set forth in claim 1, wherein said edges are spaced apart slightly at the leading end of the female member to provide a tapered lead-in slot for the projection.

3. The combination set forth in claim 2, wherein the end of said aperture toward the leading end of the female member is generally V-shaped to facilitate Withdrawal of the male member from the female member.

References Cited UNITED STATES PATENTS 1,425,153 8/1922 Vigneault. 2,944,241 7/ 1960 Londell 3 39-91 2,974,302 3/1961' Ellis 339278 10 MARVIN A. CHAMPION, Primary Examiner.

EDWARD C. ALLEN, Examiner. P. A. CLIFFORD Assistant Examiner,

Claims (1)

1. AN ELECTRICAL CONNECTING MEANS COMPRISING A PAIR OF MALE AND FEMALE TERMINAL MEMBERS DIMENSIONED FOR SNUG TELESCOPIC ENGAGEMENT, SAID FEMALE MEMBER HAVING A HOLLOW PORTION PROVIDED WITH A PAIR OF JUXTAPOSED SEPARABLE EDGES WHICH EXTEND AXIALLY OF THE TERMINAL MEMBER, SAID MALE MEMBER HAVING A RADIALLY EXTENDING PROJECTION ADJACENT ONE END THEREOF ADAPTED TO ENGAGE BETWEEN SAID JUXTAPOSED EDGES TO SEPARATE THEM AND THEREBY CIRCUMFERENTIALLY EXPAND THE HOLLOW PORTION OF THE FEMALE MEMBER WHEN TELESCOPICALLY ENGAGED THEREWITH, SAID FEMALE MEMBER HAVING AN OPENING IN THE WALL THEREOF CONTIGUOUS TO AND IN ALIGNMENT WITH SAID JUXTAPOSED EDGES TO RECEIVE SAID PROJECTION WHEN THE MEMBERS ARE FULLY TELESCOPED TO ALLOW SAID EDGES TO RETURN TOWARD THEIR FREE CONDITION AND THEREBY CIRCUMFERENTIALLY CLOSE ON THE MALE MEMBER.

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