US3350675A - Locking electrical connector - Google Patents

Description

Oct. 31, 1967 J. MISENCIK ETAL 3,350,675

LOCKING ELECTRICAL CONNECTOR Filed Oct. 11, 1965 2 Sheets-Sheet 1 FIG.3

INVE NTORS ATTORN EY5 United States Patent Ofifice ABSTRACT OF THE DISCLOSURE The instant device is a plug and socket connector having a latching means comprising a slotted prong having an enlarged opening at the inner end of the slot, the

prong being disposed on the plug and in the socket, a headed member receivable in the enlarged opening of the prong and mounted on the outer end of a solenoid armature by a shank portion receivable in the slot of the prong. The armature moves laterally with respect to the prong and is spring biased to the outer position. A mechanical operator, normally spring biased outwardly and having a path of movement parallel to the slotted prong,

is provided with a notch which receives the headed member in the inner position of the operator and the outer position of the headed member. This corresponds to the latching or unlatching position. The normal position of the mechanical operator, being outward, holds the headed member in a position to block latching or unlatching. The solenoid is in series with a switch and the two are connected between the opposite poles of the power terminals of the socket. A switch operator mounted on the mechanical operator is spaced from the switch in the outer position of 'said mechanical operator, whereby the solenoid is normally deenergized. When the socket terminals are deenergized, the mechanical operator, when pushed inwardly, closes the switch but to no purpose and vthe spring biased solenoid drives the headed member outwardly to. permit latching or unlatching. When the socket terminals are energized, pushing the mechanical operator inward closes the switch in series with the solenoidjand the latter prevents outward movement of the headed member, to thus block latching or unlatching.

This invention relates to a locking electrical connector and, more particularly, to a connector of the type having a separable body and plug.

In electrical cable connectors designed to supply relatively high power loads, it is important that suitable provisions be'made to prevent the connectors from being engaged or disengaged while energized. This is because of the arcing which occurs when making and breaking sucha circuit and the risk of injury both to equipment and to personnel'which is apt to result from such arcing.

'Varioustypes of mechanical and electrical locks have been proposed for use with cable connectors to prevent their engagement or disengagement while energized. One

type of locking arrangement which has proved successful is disclosed in UnitedStates Patent No. 3,131,012, which patent construction is that the solenoid remains energized at all times during which the connector body is ener- 3,350,675 Patented Oct. 31, 1967 gized. Thus, the solenoid must be designed and engineered for continuous operation. It would be desirable to provide a connector having the same operating characteristics as that of the patented device, but wherein the solenoid would not be continuously energized.

Accordingly, it is a primary object of the present in vention to provide an improved electrical connector having a safety locking means. Other objects are to provide such a connector wherein the locking means includes a solenoid which is normally deenergized, and to provide a connector which is reliable and safe.

The manner in which the foregoing objects are achieved will be more apparent from the following description, the appended claims and the figures of the attached drawings, wherein:

FIG. 1 is a perspective view of a separated connector body and plug in accordance with this invention, a portion of the plug being broken away to illustrate its construction;

FIG. 2 is a partial cross sectional view of the connector body and plug of FIG. 1 in their mated position;

FIG. 3 is a partial view of the connector body of FIG. 2, showing the mechanism in a different stage of operation;

FIG. 4 is a perspective detail view illustrating the locking operation; and

FIGS. 5-10 are partially schematic illustrations of various operating stages of the invention.

The objects of the invention are achieved by means of an electrical connector wherein the connector body includes a plurality of contacts connectable to a power supply. Solenoid means is provided on the connector body and is connected for energization from the power supply. The connector body also includes normally open switch means which are in series with the solenoid. The solenoid includes a core which is movable between a solenoid energized position and a solenoid deenergized position. The core, while in its energized position, is arranged to prevent engagement and disengagement of the connector body with a mating connector plug. A spring normally biases the core to its deenergized position, The connector body additionally includes latching means which normally retains the core in its energized position, but is manually operable to release the core and close the switch.

With particular reference to FIG. 1, there is illustrated a connector including aconnector body 10 and aconnector plug 12. Theplug 12 includes aninsulating base 14 from which project theusual line blades 16, 18 and agrounding blade 20. These blades are connected in the usual manner by wiring means (not shown) to the conductors of acable 22 supplying the load. In addition to the line and grounding blades there is provided alocking blade 24. The locking blade is longer than the electrical contact blades and is bifurcated at its outer end, as shown more clearly in FIG. 4, to form anarrow slot 26 terminating in around aperture 28 having a diameter greater than the width of theslot 26. Theplug 12 further includes anouter steel housing 30 which extends beyond the contact blades to form askirt 32.

Theconnector body 10 includes asteel housing 34 within which is mounted a generally disc-shaped base member 36 constructed of insulating material. A central insulatingmember 38 is positioned adjacent thebase member 36. An insulatingcap member 40 is positioned against thecentral member 38 and the central member and cap are enclosed within aninsulating shell 42. Shell 42 is generally cup-shaped to provide aforward face 44 which definesopenings 46 for receiving thecontact blades 16, 18, 20 of the connector plug and anopening 48 for receiving thelocking blade 24. The entire connector body assembly is secured together by means of 3screws 50 which extend from theforward face 44, through the assembly into the tapped openings in the rear wall of thehousing 34. Theforward end 52 ofhousing 34 is flared outwardly as shown to provide an annular recess for receiving theskirt 32 of theconnector plug 12 when mated therewith.

It will be noted from FIG. 2 that thecentral member 38 of the connector body is substantially hollow so as to form aswitch chamber 54 therein. In addition, the mating ends of thecentral member 38 and thecap member 40 are inletted so as to retain asolenoid 56 therebetween. The solenoid is positioned so that itsmagnetic core 58 is radially vertically movable as viewed in FIG. 2. Thecap member 40 defines aradial passage 60 into which the lower end of the core may extend andpassage 60 communicates with alongitudinal guideway 62 within which is mounted alatching plunger 64 which includes ashoulder 65 and a small diameter end which extends through apassage 37 inbase member 36 and through the rear wall ofhousing 34 to form arelease button 66. Outward motion oflatching plunger 64 is limited by arecess 39 which is positioned to receiveshoulder 65. Thecap member 40 and thecentral member 38 also define a guideway aligned with opening 48 for receiving alocking blade 24. The inner surface of theshell 42 is cut away to form three peripherally displacedcontact housing chambers 68 which enclose the usualfemale contacts 70 for receiving the line and grounding blades of the plug. As this portion of the construction is conventional, only one of thecontacts 70 is illustrated. Each contact includes suitable wiring means, such as thescrew connector 72, for securing one of the conductors 74 of an electricalpower supply cable 76.

Thesolenoid 56 includes alead 78 which is connected to thesame screw connector 72 as the conductor 74. Theother lead 80 is connected to the fixedpole 82 of anelectrical switch 84 which is mounted within theswitch chamber 54. Anotherlead 86 extends from themovable pole 88 of the switch to one of the other screw connectors 72 (not shown) to which a line conductor of thepower supply cable 76 is secured. It will be noted that themovable pole 88 is positioned adjacent thenylon latching plunger 64 and that a switch actuatinglug 90 on the latching plunger is positioned to engage thepole 88 and close the switch when therelease button 66 is in its depressed position, as illustrated in FIG. 2.Latching plunger 64 also defines adepression 67 for receiving the end ofcore 58. Thelatching plunger 64 is normally biased outwardly, as indicated by FIG. 3 and the dotted line of FIG. 2, by means of aspring 92 housed in the end ofguideway 62. In addition, it will be noted that thesolenoid core 58 is normally urged outward from thesolenoid 56 by means of aspring 94 mounted within the solenoid coil. It is important to note that the outer end of thesolenoid core 58 includes anarrow pin portion 96 which terminates in an enlargedrounded head 98. The diameter ofpin 96 is sufiiciently small that it will easily pass through theslot 26 in lockingblade 24 and theenlarged head 98 is small enough to pass easily through theaperture 28 in the locking blade but is too large to pass through the slot.

Operation The normal deenergized arrangement of the movable parts of the body is illustrated in FIG. 3. Thespring 92 maintains the latchingplunger 64 in its outwardmost position. Thespring 94 Within thesolenoid 56 causes thehead 98 of the solenoid core to rest against the latching plunger. Under these circumstances, thehead 98 is positioned in alignment with the opening which would normally admit lockingblade 24. Ashead 98 is larger thanslot 26 on the locking blade, theconnector plug 12 cannot be mated with theconnector body 10.

Assuming that thepower supply cable 76 is deenergized, the parts are mated by depressing therelease button 66 4 as illustrated in FIG. 2. This causes thedepression 67 to be displaced axially toward the left, allowing thespring 94 to move thehead 98 downwardly into the depression and out of alignment with the opening for lockingblade 24. The locking blade may then be inserted, as shown in FIG. 4, allowing theplug 12 to be mated with thebody 10.

When mating is complete, as shown in FIG. 2, thebutton 66 may be released. This causes thedepression 67 on latchingplunger 64 to be returned to its original position, camming thehead 98 upwardly into theaperture 28 of the locking blade. Theplug 12 cannot thereafter be removed without depressing thebutton 66.

It will be noted that theswitch 84 is normally open until therelease button 66 is depressed, causing themovable pole 88 to contact the fixedpole 82. The significance of this can be best understood by reference to FIGS. 5 and 6. Assume that the power supply cable is energized, and the body and plug are connected. This condition is illustrated in FIG. 6, wherein it will be noted thathead 98 is held in the locking position relative to lockingblade 24 by latchingplunger 64. It will also be noted thatswitch 84 is opened so that the solenoid is deenergized. If disengagement of the plug from the body is attempted by depressing thebutton 66 to force the latchingplunger 64 to the left, as viewed in FIG. 5, the lug forces themovable pole 88 ofswitch 84 against the fixedpole 82, thereby closing the switch and energizing the solenoid. The solenoid then retains thehead 98 in its raised position so that the plug cannot be separated from the body.

A similar condition will exist if the connector plug and body are initially separated and if an attempt is made to mate them while the power cable is energized. This is illustrated in FIGS. 7 and 8. In FIG. 7, it will be noted that theenlarged head 98 of the solenoid core is in line with thelocking blade 24 so that the plug is unable to enter the connector body. Depression of the latchingplunger 64, as shown in FIG. 8, closes theswitch 84 thus energizing the solenoid and retaining theenlarged head 98 in the same position.

An alternative arrangement which operates in a somewhat dififerent fashion is illustrated in FIGS. 9 and 10. In this arrangement, a modifiedlatching plunger 100 is employed wherein thedepression 102 is formed with a relativelysharp edge 104 at its forwardmost end. The advantage of this construction is that theenlarged head 98 of the spring-loadedsolenoid core 58 serves as a mechanical latch whenever the solenoid is deenergized. As theedge 104 is unable to cam thehead 98 upwards, it serves to retain theplunger 100 in its forwardmost osition. Thus, thelocking blade 24 is allowed to enter without requiring that the button be depressed for each mating. However, as soon as the solenoid is energized, thehead 98 is retracted as shown in FIG. 10, allowing theplunger 100 to return to its normal latching position. It will thus be seen that the illustrated invention achieves the objectives hereinbefore set forth by reventing either engagement or disengagement of an electrical connector while the power supply cable is energized. Furthermore, this result is achieved without requiring that the solenoid remain energized. The solenoid, under these conditions, is energized only when the manual release button is depressed.

It is believed that the many advantages of this invention will be immediately apparent to those skilled in the art. It will also be understood that a number of variations and modifications may be made in this invention without departing from its spirit and scope. Accordingly, the foregoing description is to be construed as illustrative only, rather than limiting. This invention is limited only by the scope of the following claims.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In an electrical connector body including a plurality 'of electrical contacts connectable to a power supply, the

improvement which comprises: solenoid coil means connected for energization from said power supply; normally open switch means in series with said solenoid coil means; a solenoid core movable between a solenoid-energized position and solenoid-deenergized position, said core in its energized position being arranged to prevent engagement and disengagement of said connector body with a mating connector plug; spring means normally biasing said core to its deenergized position; and latching means on said body normally retaining said core in its energized position but manually operable to release said core and close said switch means.

2. The improvement of claim 1 wherein said body defines a longitudinal passage for receiving a bifurcated locking blade having a longitudinally extending slot terminating in an aperture of a transverse diameter greater than the width of said slot and wherein said core comprises: a pin portion slidably engageable by said slot when said core is in its deenergized position; and an enlarged head portion engageable with said aperture when said core is in its energized position.

3. The improvement of claim 1 wherein said latching means comprises: a latching plunger axially slidable in said body between a first and a second position along a path transverse to the motion of said core, a first portion of said plunger being adapted to retain said core when in said first position, and a second portion of said plunger being adapted to release said core when in said second position; biasing means normally urging said plunger to its first position; a release button portion of said plunger positioned externally of said body and depressible to move said plunger to its second position; and switch actuating means on said plunger operable to close said switch means upon movement of said plunger to said second position.

4. The improvement of claim 3 wherein said switch means comprises a fixed contact and a movable contact and wherein said switch actuating means comprises a lug on said plunger engageable with said movable contact.

5. The improvement of claim 3 wherein said second portion ofsaid plunger defines a depression for receiving the end of said core therein.

6. In a longitudinally extending electrical connector body including a plurality of electrical contacts connectable to a power supply cable, and defining a plurality of contact blade receiving passages and a locking blade receiving passage, the improvement which comprises: solenoid coil means connected for energization from said power supply cable; a solenoid core transversely movable relative to said body between a solenoid-energized position and a solenoid-deenergized position, a free end of said core extending from said coil means and including a pin portion terminating in an enlarged head, said head being aligned with said locking blade receiving passage when said core is in its solenoid-energized position, and said pin portion being aligned with said locking blade receiving passage when said core is in its solenoid-deenergized position; normally Open switch means in series with said solenoid coil means; spring means normally biasing said core to its deenergized position; a latching plunger axially slidable in said body between a first and a second position along a path transverse to the motion of said core, a first portion of said plunger being adapted to retain said core in its energized position when in said first position, and a depressed portion of said plunger being adapted to release said core when in said second position; biasing means normally urging said plunger to its first position; a release button portion of said plunger positioned externally of said body and depressible to move said plunger to its second position; and switch actuating means on said plunger operable to close said switch means upon movement of said plunger to said second position.

7. The improvement of claim 6 wherein said switch means comprises a fixed and a movable contact and wherein said switch actuating means comprises a lug on said plunger engageable with said movable contact.

8. The improvement of claim 6 wherein said depressed portion includes a latching edge engageable with said head to retain said plunger in its second position when said head is seated therein.

References Cited UNITED STATES PATENTS 2,298,313 10/1942 Ross 339-12 X 2,735,992 2/1956 Bailey 339-84 X 3,131,012 4/1964 Healy 339-12 MARVIN A. CHAMPION, Primary Examiner. PATRICK A. CLIFFORD, Assistant Examiner.

Claims (1)

1. IN A ELECTRICAL CONNECTOR BODY INCLUDING A PLURALITY OF ELECTRICAL CONTACTS CONNECTABLE TO A POWER SUPPLY, THE IMPROVEMENT WHICH COMPRISES: SOLENOID COIL MEANS CONNECTED FOR ENERGIZATION FROM SAID POWER SUPPLY; NORMALLY OPEN SWITCH MEANS IN SERIES WITH SAID SOLENOID COIL MEANS; A SOLENOID CORE MOVABLE BETWEEN A SOLENOID-ENERGIZED POSITION AND SOLENOID-DEENERGIZED POSITION, SAID CORE IN ITS ENERGIZED POSITION BEING ARRANGED TO PREVENT ENGAGEMENT AND DISENGAGEMENT OF SAID CONNECTOR BODY WITH A MATING CONNECTOR PLUG; SPRING MEANS NORMALLY BIASING SAID CORE TO ITS DEENERGIZED POSITION; AND LATCHING MEANS ON SAID BODY NORMALLY RETAINING SAID CORE IN ITS ENERGIZED POSITION BUT MANUALLY OPERABLE TO RELEASE SAID CORE AND CLOSE SAID SWITCH MEANS.

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