US3530428A

US3530428A - Electrical terminal

Info

Publication number: US3530428A
Application number: US537976A
Authority: US
Inventors: Alfred M Zak
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-11-08
Filing date: 1966-03-28
Publication date: 1970-09-22
Anticipated expiration: 1987-09-22
Also published as: GB1162990A; DE1615085A1; US3325775A

Description

Sept. 22, 1970 A. M. ZAK 3,530,428

ELECTRICAL TERMINAL Filed March 28. 1966 2 Sheets-Sheet 1 1 VEN 0R. ALFRKD ZTAK ATTORNEYS Sept. 22, 1970 A. M. ZAK 3,530,428

ELECTRICAL TERMINAL Filed March 28. 1966 2 Sheets Sheet 2 132 I65 :55 mo /06 142 I04 148 [30 62 IXVENT R. ALFRED M. Z AK ATTbRNEYS 3,530,428 Patented Sept. 22, 1970 3,530,428 ELECTRICAL TERMINAL Alfred M. Zak, 6110 Casmere Ave., Detroit, Mich. 48212 Continuation-impart of application Ser. No. 506,657, Nov. 8, 1965. This application Mar. 28, 1966, Ser.

Int. Cl. H01r 13/42 U.S. Cl. 339-217 7 Claims This application is a continuation-in-part of my prior co-pending application Ser. No. 506,657, filed Nov. 8, 1965, now U.S. Pat. 3,325,775.

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 features 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 with the application of relatively little pressure.

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.

A further object of the invention resides in the provision of a terminal construction which assures good electrical contact between the terminal members and is de signed to hold tightly without collapsing when telescopically engaged.

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 3--3 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 block as viewed along the line 6-6 of FIG. 5 with the terminal removed.

FIG. 7 is a fragmentary sectional view similar to FIG. 1 and showing a modified form of terminal construction.

FIG. 8 is a perspective view of the male terminal shown in FIG. 7.

FIG. 9 is a perspective view of the female terminal shown in FIG. 7.

FIGS. 10 and 11 are fragmentary sectional views showing the manner in which the male and female terminal members illustrated in FIG. 7 can be released from within their respective terminal blocks.

In FIG. 1 a pair of

terminal blocks

10 and 12 are illustrated. As is conventional, these terminal blocks are formed of an electrical insulating material such as Bakelite. Within block 10 there is arranged a female contact terminal 14, and within block 12 there is arranged a male contact terminal member 16. These two terminal members 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 of tabs 18 which are adapted to be crimped around the insulating coating 20 of a stranded wire conductor 22. Each terminal is also formed with a second pair of tabs 24 spaced axially from tabs 18, tabs 24 being adapted to be crimped over the bared end of the stranded conductor 22 to provide good electrical contact between the terminal and the conductor.

Terminal 14 is formed with a cylindrical body portion 26 and terminal 16 is formed with a cylindrical body portion 28. The inner diameter of the body portion 26 of terminal 14 is dimensioned relative to the outer diameter of the body portion 28 of terminal 16 such that they have a slight interference fit. For example, in a terminal construction wherein the outer diameter of body portion 28 is about .093 inch, the nominal inner diameter of body portion 26 may be about .003 inch less, so that the insertion of body portion 28 into the body portion 26 requires a slight circumferential expansion of body 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 of terminal 14 is indicated at 30 and the corresponding parting line on terminal 16 is indicated at 32.

Terminal block 10 is fashioned with a bore 34 dimensioned to receive the cylindrical body portion 26 of terminal 14 and a counterbore 36 dimensioned to receive the enlarged outer end of terminal 14 at the tabs 18. These two bores are separated by a shoulder 38. The body portion 26 of terminal 14 is fashioned with a pair of relatively rigid radially outwardly extending lugs 40 that are adapted to abut against shoulder 38 and thus limit movement of terminal 14 in a direction inwardly of block 10, that is, in a direction toward the right in FIG. 1.

Terminal block 12 is fashioned with a cylindrical socket 42 adapted to receive the cylindrical body portion 28 of terminal 16 with a rather close fit and a counterbore 44 adapted to receive the enlarged outer end of terminal 16 at tabs 18. The junction between these two bores defines a shoulder 46 which is adapted to be engaged by lugs 48 on terminal 16 to limit the extent to which terminal 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 or slot 50, and bore 46 is likewise formed with a longitudinally extending recess or slot 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 a tab 56, and slot 52 accommodates a tab 58. The construction and function of each. of these tabs is the same, and for this reason only tab 56 will be described in detail. Tab 56 is struck inwardly from the wall of body portion 26 about bend line 57, and extends across the hollow interior of body portion 26 at an acute angle to the longitudinal axis of the terminal. At its free end tab 56 extends through an opening 60 in body portion 26 which is diametrically opposite the opening 62 which results from striking tab 56 inwardly. It will be noted that tab 56 engages the edge 64 of opening 60 so that the extent to which it can be flexed outwardly of opening 60 is effectively limited by the edge 64. Edge 64 is located so as to accurately control the extent to which the free end portion 66 of tab 56 projects radially outwardly beyond the outer periphery of cylindrical body portion 26. As is clearly evident from FIG. 1, when terminal 14 is inserted in block with lugs 40 engaging shoulder 38, the end portion 66 of tab 56 is spaced slightly from the end 67 of slot 50.

Tab 58 on terminal 16 is likewise struck inwardly from the cylindrical body portion 28 about bend line 69 and extends across the hollow interior of body portion 28 at an acute angle to the longitudinal axis of the terminal with its free end portion '68 projecting outwardly through an opening 70 in body portion 28. Tab 58 bears against the edge 72 of opening 70 to limit the extent to which tab 58 can flex in a direction outwardly of body portion 28. With terminal 16 fully inserted in block 12, that is, with lug 48 engaging shoulder 46, the free end portion 68 of tab 58 is spaced slightly from the end 65 of slot 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 the respective 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 of terminal 16 is preferably formed with a tapered nose 74 to facilitate its insertion in the open end 76 of terminal 14. In addition, tapered nose 74 is fashioned with a radially extending lug 78 which is aligned with the parting line 32 on the cylindrical 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 of terminal 14 are notched or tapered as at 82, to facilitate entry of lug 78 between the contacting edges which form the parting line 30 on terminal 14. Terminal 14 is also formed with an aperture 84 positioned to receive lug 78 when terminal 16 is fully inserted in terminal 14. To facilitate withdrawal of terminal 16 from terminal 14, the leading edges of aperture 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 of terminal 16 and block 12, for example, terminal 16 is inserted leading end foremost through the open end 87 of bore 44. The portion of the block aligned centrally of tab slot 52 and adjacent shoulder 46 is fashioned with a radial slot 88 to accommodate lug 78. As the end 68 of tab 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 the smaller bore portion 42. When tab 58 is aligned with slot 52, the tab snaps radially outwardly into slot 52 to the extent permitted by the edge 72 of the opening 70 in the terminal. The terminal is thus effectively locked in the terminal block. Terminal 14 is engaged within its terminal 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 the terminal block 10 to align each of the nose portions 74 of terminals 16 with the open end 76 of a corresponding terminal 14 in block 10; Insertion of the body portions 28 into the terminal block 10 is facilitated by a slight chamfer 90 at the open end of the bore 34 of terminal block 10. As the leading ends of terminals 16 are advanced into terminals 14, the lug 78 on each terminal 16 enters between the tapered edges 82 on the corresponding body portion 26 to facilitate the circumferlltial expansion of each terminal 14 and thus separate the contacting edges forming the parting line 30.

When the juxtaposed faces 54 of the two terminal blocks come into abutting relation, each lug 78 snaps into a corresponding aperture 84 and thus causes each body portion 26 to contract into tight engagement with the associated body portion 28 of terminals 16. To disconnect the terminals the operation is reversed, and the force required to pull them apart is lessened by the provision of lug 78 in conjunction With the tapered edges 86 of aperture 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 the

tabs

56, 58 are rigidly backed adjacent their outer ends against edges 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 the

tabs

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 the

tabs

56, 58 so that they extend across the hollow interior of their respective terminal as shown, 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 the

inner end

67, 69 of the corresponding slot in the terminal block to enable the tab to flex radially inwardly through the opening 70 or 60, as the case may be. In FIGS. 1-6- the inclination of

tabs

56, 58 to the axis of the terminals is illustrated as about 45. This inclination can be increased slightly or decreased considerably but it is important that in any event the portion of the tab traversing the hollow interior of the terminal be inclined to the axis of the terminal at an angle substantially less than in order to obtain all of the above-described advantages of my invention.

In FIGS. 7 through 11 there is shown a modified form of the terminal construction which differs slightly from that previously described and which is particularly adapted for very small diametric terminals. The terminal blocks here illustrated are designated 100, 102, block being adapted to accommodate the female terminal 104 and block 102 being adapted to accommodate the male terminal 106. As in the previous embodiment, both terminals are of generally cylindrical shape and are adapted to be formed from flat sheet metal in progressive dies. Each terminal is formed with tabs 108, adapted to be crimped to the ends of the wires 112. The cylindrical body portion 114 of terminal 104 is formed with an opening 116 and a pair of inclined lugs 118. The cylindrical body portion 120 of terminal 106 is likewise formed with an opening 122 and a pair of inclined lugs 124. The cylindrical body portion 120 of terminal 106 is dimensioned to have a slight interference fit within the cylindrical body portion 114 of terminal 104.

Each terminal has an inwardly struck tab thereon which is flexible and resilient, the tab for the female terminal being designated 126 and the tab for the male terminal being designated 128. These two tabs are formed generally in the same manner and to the same configuration so that a detailed description of one will suflice. Referring to tab 126 for example, it will be observed that the tab is struck inwardly from the wall of cylindrical portion 114 as at bend line 130. Since the portion 114 is of circular shape and cross section, bend line 130 will comprise generally a segment of a circle. The tab 126 comprises a first portion 132 which is bent inwardly at a relatively steep angle, for example, about 70 to the longitudinal axis of the terminal. It is then reversely bent at the straight bend line 134 so that the central intermediate portion 136 of tab 126 exends across the hollow interior of portion 114 at an angle of about to the longitudinal axis of the terminal. Adjacent its free end tab 126 is formed with a third bend line 138 so that the extreme end portion 140 of tab 126 projects outwardly through opening 116 in a plane which is substantially perpendicular to the longitudinal axis of the terminal.

Terminal block 100 is formed with a cylindrical socket 141 comprising a first bore 142 which terminates at its inner end in tapered seat 144 which connects with a cylindrical bore 146 dimensioned to receive the body portion 114 of terminal 104 with a slip fit. The other end of bore 146 is defined by a radially outwardly extending shoulder 148 that defines an enlarged bore portion 150 extending to the forward face 152 of terminal block 100. Seat 144 and shoulder 148 are spaced apart axially such that when the female terminal 104 is inserted into the terminal block, lugs 118 engage seat 144 and the projecting portion 140 of tab 126 engages shoulder 148. When terminal 104 is inserted into block 100 through the open end of bore 142, the tapered seat 144 engages the projecting portion 140 of tab 126 and cams the tab inwardly to clear bore 146. When the terminal is fully inserted in the terminal block as shown in FIG. 7, tab 126 flexes outwardly so that portion 140 engages shoulder 148 to lock the terminal in place.

Terminal block 102 is likewise formed with a cylindrical socket 153 comprising a first bore 154 terminating in tapered seat 156 which connects with one end of a bore 160. The other end of bore 160 is defined by a shoulder 158 which connects bore 160 with an enlarged bore 162 extending to the forward end face 163 of block 102. The male terminal 106 is insertable in its terminal block 102 and retained therein by

shoulders

156, 158 in the same manner as described above with respect to terminal 104.

In the case of very small dimensioned terminals the construction shown in FIGS. 7 through 11 has advantages over the embodiments previously described. By forming the projecting portion 140 of

tabs

126, 128, so as to extend perpendicularly of the axes of the terminals, the possibility of the tabs collapsing due to an axially directed pressure is even more remote. This is particularly true when the male terminals in one block are inserted in the female terminals in the other block. On one axial side of tab 140 it is supported by the straight edge 164 of the opening through which it projects and and on the opposite axial side it is supported by the shoulder in the terminal block, that is shoulder 148 in the case of tab 126 and shoulder 158 in the case of tab 128. Since the tab portion 140 projects outwardly beyond the outer surface of the cylindrical body portion of the terminal only a slight extent, it is not readily bendable as a result of axial pressure applied thereto by the shoulder of the terminal block. In addition, I have found that by striking the tab inwardly with a reverse bend such as shown at 130, 132, 134 the flexibility and the resiliency of the tab is improved over the construction shown in FIGS. 1 through 6. Since the bend line 130 is by necessity a curved line, the ability of the tab to flex about this bend line is rather limited. However, the tab itself in this embodiment is flat and bend line 134 is straight. The intermediate portion 136 of each tab is, therefore, freely flexible about the bend line .134 and the ability of the tab to return to the position illustrated in FIG. 7 after it has been deflected inwardly is not impaired. This is important not only because the tabs have to flex inwardly when the terminals are initially inserted in their respective terminal blocks but also because it enables the terminals to be withdrawn from and reinserted into the terminal blocks without impairing or destroying the holding power of

tabs

126, 128.

The provision of the perpendicular projecting end portions of the

tabs

126, 128 involves another advantage; namely, the ability to easily deflect the tabs in wardly for removal of the terminals from within their respective terminal blocks. Referring to FIGS. 10 and 11, it will be observed that these tabs can be deflected inwardly to a position clearing the bores 146, by simply inserting through the open end of the respective terminal a straight wire-like element 166 as distinguished from a specially formed tool. For example, the element 166 can be conveniently formed from a partially straightened conventional paper clip 188. As the wire element .166 is inserted into the open end of the terminal, it engages the intermediate portion 136 of the tab to deflect it or cam it inwardly. However, the extent of axial inward movement of wire 166 is limited by the engage ment by the end of the wire with the perpendicularly directed tab portion 140. Since the end of wire 166 abuts directly against tab portion 140 the possibility of riding over the free edge of tab 140 with the wire is eliminated and thus the tendency to deflect the tab inwardly too great an extent is avoided. Obviously if the tab were deflected too great an extent, it would lose its ability to recover its required position for enabling the projecting portion 140 to engage the adjacent shoulder on the terminal block for locking the terminal in the block.

The inward deflection of tab portion 140'in this arrangement can be controlled to that required or desired by simply increasing or decreasing the diameter of wire 166. This is clearly evident from FIGS. 10 and 11 since when the wire is fully inserted in the end of the terminal to a position where it abuts tab portion 140, one side of the wire will be engaged with the inside of the cylindrical wall forming the body portion of the terminal and the diametrically opposite side of the wire will be contacting the intermediate portion .136 of the tab adjacent the bend line 138. The lateral clearance space within the hollow interior of the terminal at each side of the tab is less than the diameter of the wire element. Thus the end of the wire element cannot slip past the tab.

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 interconnected by lugs 94 with carrier strips 96 to enable handling of the terminals as reels. For example, until the individual terminals are crimped onto the wire, they are connected to the carrier strips or runners 96 so that they can be reeled. The die which crimps the

wire gripping tabs

18, 24 in FIGS. 1-6 and 108, 112 in FIGS. 711 is preferably fashioned so that it simultaneously shears the lugs 94 from the opposite ends of the terminals. 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. For example, lugs 40, 48, 118, and 124 are short rigid projections which do not bend readily and the projecting portions of

tabs

56, 58, 126 and 128 are likewise short and not subject to entanglement.

Iclaim:

1. An electrical terminal of the type adapted to be in-' serted within a socket of a terminal block and having an elongated body with a forward and rear end, said body comprising a hollow portion of generally circular cross section having an opening in one side thereof and a tab struck inwardly from the opposite side thereof, said tab traversing the interior of said hollow portion at an acute angle to the longitudinal axis of the hollow portion and projecting through said opening at its free end, said tab being connected with the hollow portion by a first bend extending around a portion of the circular periphery of said hollow portion, said tab having a second bend therein spaced lengthwise of the tab from said first bend, the portion of the tab provided with the second bend being generally flat and the second bend extending trans versely across said tab and being located closely adjacent the first bend and remotely from the free end of said tab, said tab being adapted to engage shoulder means on the terminal block to limit movement of the terminal in the socket in the direction of said rear end, the projecting portion of the tab being axially offset substantially from the portion of the tab connected with said opposite side of said hollow portion, said opening having suflicient axial extent in a direction rear-wardly of the projecting portion of the tab to permit flexing of the tab about said second bend radially inwardly through said opening in the manner of a leaf spring, said opening having two sides and hav ing one end located closely adjacent the projecting portion of the tab on the forward side thereof to limit flexing of the tab in a direction toward the forward end of the terminal.

2. An electrical terminal as set forth in claim 1 wherein the portion of said tab between said two bends extends inwardly from the connection of the tab with said hollow portion at a relatively steep angle to the longitudinal axis of the hollow portion and then the tab extends towards its free end at a lesser angle to the longitudinal axis of the hollow portion.

3. An electrical terminal as set forth in claim 2 where- 8 in said second bend comprises a sharply defined straight bend line.

4. An electrical terminal as set forth in claim 2 wherein said steep angle lies in the range from about to and said lesser angle lies in the range of about from 20 to 40.

5. An electrical terminal as set forth in claim 1 wherein said tab is formed with a third bend between said second bend and the free end thereof, the portion of the tab between said third bend and said free end extending through said opening and being substantially perpendicular to the longitudinal axis of said hollow portion.

6. An electrical terminal as set forth in claim 5 Wherein said third bend is disposed within said hollow portion and closely adjacent the inner periphery of said hollow portion at said opening.

7. An electrical terminal as set forth in claim 6 wherein the forward end of said elongate body is provided with an axially opening central aperture adapted to accomodate the insertion of a tool therein for enabling the free end of the tab to be retracted through said opening in one side of the hollow portion to thereby permit removal of the terminal from within the socket of a terminal block.

References Cited UNITED STATES PATENTS 2,689,337 9/1954 Burtt et al. 339217 2,779,007 1/1957 Cunningham 339-217 X 2,999,221 9/1961 Ellis et al. 339217 X 3,058,091 10/1962 Henschen 339-217 X 3,059,213 10/1962 Lalonde 339217 X 3,156,517 11/1964 Maximolf et al. 339-217 X 3,215,975 11/1965 Kinkaid 339-217 X MARVIN A. CHAMPION, Primary Examiner P. A. CLIFFORD, Assistant Examiner US. Cl. X.R. 339-176, 213

Claims

1. AN ELECTRICAL TERMINAL OF THE TYPE ADAPTED TO BE INSERTED WITHIN A SOCKET OF A TERMINAL BLOCK AND HAVING AN ELONGATED BODY WITH A FORWARD AND REAR END, SAID BODY COMPRISING A HOLLOW PORTION OF GENERALLY CIRCULAR CROSS SECTION HAVING AN OPENING IN ONE SIDE THEREOF AND A TAB STRUCK INWARDLY FROM THE OPPOSITE SIDE THEREOF, SAID TAB TRAVERSING THE INTERIOR OF SAID HOLLOW PORTION AT AN ACUTE ANGLE TO THE LONGITUDINAL AXIS OF THE HOLLOW PORTION AND PROJECTING THROUGH SAID OPENING AT ITS FREE END, SAID TAB BEING CONNECTED WITH THE HOLLOW PORTION BY A FIRST BEND EXTENDING AROUND A PORTION OF THE CIRCULAR PERIPHERY OF SAID HOLLOW PORTION, SAID TAB HAVING A SECOND BEND THEREIN SPACED LENGTHWISE OF THE TAB FROM SAID FIRST BEND, THE PORTION OF THE TAB PROVIDED WITH THE SECOND BEND BEING GENERALLY FLAT AND THE SECOND BEND EXTENDING TRANSVERSELY ACROSS SAID TAB AND BEING LOCATED CLOSELY ADJACENT THE FIRST BEND AND REMOTELY FROM THE FREE END OF SAID TAB, SAID TAB BEING ADAPTED TO ENGAGE SHOULDER MEANS ON THE TERMINAL BLOCK TO LIMIT MOVEMENT OF THE TERMINAL IN THE SOCKET IN THE DIRECTION OF SAID REAR END, THE PROJECTING PORTION OF THE TAB BEING AXIALLY OFFSET SUBSTANTIALLY FROM THE PORTION OF THE TAB CONNECTED WITH SAID OPPOSITE SIDE OF SAID HOLLOW PORTION, SAID OPENING HAVING SUFFICIENT AXIAL EXTENT IN A DIRECTION REARWARDLY OF THE PROJECTING PORTION OF THE TAB TO PERMIT FLEXING OF THE TAB ABOUT SAID SECOND BEND RADIALLY INWARDLY THROUGH SAID OPENING IN THE MANNER OF A LEAF SPRING, SAID OPENING HAVING TWO SIDES AND HAVING ONE END LOCATED CLOSELY ADJACENT THE PROJECTING PORTION OF THE TAB ON THE FORWARD SIDE THEREOF TO LIMIT FLEXING OF THE TAB IN A DIRECTION TOWARD THE FORWARD END OF THE TERMINAL.