US3383480A

US3383480A - Electrical connector

Info

Publication number: US3383480A
Application number: US481740A
Authority: US
Inventors: John J Phillips; John R Abbott
Original assignee: Gray and Huleguard Inc
Current assignee: Automation Industries Inc; Gray and Huleguard Inc
Priority date: 1965-08-23
Filing date: 1965-08-23
Publication date: 1968-05-14
Anticipated expiration: 1985-05-14

Description

y 1968 J. J. PHILLIPS ET AL 3,383,480

ELECTRICAL CONNECTOR John J Phllllps, John R. Abboh,

INVENTORS.

Filed Aug. 23, 1965 AIISQ E on mm :1

mm v 8 NN vm w ON N mm mm ATTORNEY.

May 14, 1968 J, PHILLlPs ET AL 3,383,489

ELECTRICAL CONNECTOR Filed Aug. 23, 1965 5 Sheets-Sheet :3

Fig. 2

John J. Phillips, John R.Abborf, INVENTORS.

Fl g. 4C

ATTORNEY.

y 1968 J. J. PHILLIPS ET AL 3,383,480

ELECTRICAL CONNECTOR Filed Aug. 25, 1965 5 Sheets$heet 5 I72 I82 I84 31 2/3 4 \v lyll E 4 V Hg. 7 (I78 -|so JohnJ Phillips I98 John R. Abbott,

INVENTORS. w r Y R B I86 4 q. 73 Sam ATTORNEY.

United States Patent 3,383,480 ELECTRICAL CONNECTOR John J. Phillips, Rolling Hills, and John R. Abbott, Sherman Oaks, Calif., assignors to Gray & Huleguard, Inc., Santa Monica, Calif., a corporation of California Filed Aug. 23, 1965, Ser. No. 481,740

13 Claims. (Cl. 200-51) This invention relates to electrical systems and switches therefor wherein one or more very sensitive loads are to be energized only in response to particular control signals and not operated as a result of stray radiations, such as electromagnetic energy. Shielding means are provided only around a limited portion of the system containing the loads. The remaining portions of the system, such as the power suply etc. are not shielded whereby the cost, weight, etc. are all reduced. However, any stray currents created in the power supply and other unshielded portions of the system will not cause any undesirable operations of the loads.

In electrical systems having a plurality of different loads it is frequently desirable to provide a common control means for actuating the loads. Under some circumstances, it is essential that each and every load be reliably energized each and every time that the control means is actuated. However, at the same time it may be equally essential that none of the loads be accidentally or prematurely energized prior to the time the control means is actuated. For example, in some forms of circuitry the loads include one or more pyrotechnic devices such as a squib or dynamite cap. These, in turn, may be effective to produce a visual signal, detonate a larger explosive, destroy or release large structures, etc. It can be appreciated that a premature energizing of such a load can cause severe and expensive property damage or even personal injury.

Loads of this nature are normally very sensitive and capable of being energized by a relatively small electrical current. In fact, it has been found that on occasions there are sufiicient amounts of electromagnetic energy in the atmosphere to energize a squib. Accordingly, in order to prevent a premature energizing of the load, it has been customary to provide shielding. Electromagnetic energy of radio frequencies or higher can be received by relatively small conductors and such energy can travel through all portions of an electrical circuit including open switches. As a result, a switch cannot be used to isolate the load and, hertofore, it has been necessary for the shielding to completely shield not only the loads but also the entire electrical system including the power supply.

Such shielding is intended to prevent any form of electromagnetic radiation such as results from radio or radar transmissions from inducing one or more currents in the control system. Although shielding can greatly reduce the amount of stray currents, in order to be reasonably elfective it has frequently bee-n necessary to completely shield the entire system. For example, it has been necessary to completely shield the circuit all the way from the original power source to the final load. Since such shielding is heavy, bulky and expensive, the prior control systems of this type have had numerous disadvantages and objections, and have not been entirely satisfactory for all types of operations.

The present invention provides means for overcoming the foregoing difliculties and limitations. More particularly, the present invention provides means whereby one or more electrical loads may be reliably actuated without a premature energizing of any of the loads. This is accomplished by providing a control system which is divided into an input or power supply portion and an output or load portion, together with switch means for controlling the 3,383,480 Patented May 14, 1968 ICC interconnection between the two sections so that the loads cannot be energized when'the two portions are disconnected but will always be energized when the two portions are connected together.

More particularly, in the limited number of embodiments disclosed herein a switch is provided in the control system which is effective to divide the system into two separate portions. Only the portion of the system containing the load is shielded against electromagnetic energy so that no stray currents can be introduced into this portion of the system. When the switch is in the open condition, the two portions are completely isolated from each other and all of the portion containing the loads is electrically connected to ground. Thus, even though there may be large amounts of electromagnetic energy present this energy will be unable to produce stray currents in the load portion. Also, even though this energy may induce stray currents in the power portion, the switch means will prevent the currents entering into the shielded portion and causing a premature actuation thereof. However, when the switch closes, the two portions are interconnected whereby the loads are always and reliably actuated. This, in turn, reduces the amount of shielding requirements to a minimum and increases the reliability of the control system.

These and other features and advantages of the present invention will become readily apparent from the following detailed description of a limited number of embodiments thereof, particularly when taken in connection with the accompanying drawings wherein:

FIGURE 1 is a schematic diagram of a control system embodying one form of the present invention with switch means (shown in cross-section) for controlling the operation of the system;

FIGURE 2 is a cross-sectional view of the switch taken substantially along the plane of line 2-2 in FIG- URE 1;

FIGURE 3 is a cross-sectional view of the switch taken substantially along the plane of line 33 in FIG- URE 1;

FIGURE 4A, 4B and 4C are diagramatic views of a portion of the operating mechanism in the switch and showing the mechanism in three separate operating conditions;

FIGURE 5 is a side elevational view of a switch embodying another form of the present invention;

FIGURE 6 is a cross-sectional'view of a portion of a switch embodying another form of the present invention and disposed in a first operating condition; and

FIGURE 7 is a cross-sectional view similar to FIG- URE 6 but showing the switch in a second operating condition.

Referring to the drawings in more detail, and particularly to FIGURES 1 through 4 inclusive, the present invention is embodied in an electrical control system 10. This system 10 is adapted to be interconnected with a plurality of electrical loads 12 and a power source, such as a battery 14, for energizing the loads 12. In addition, a suitable control means 16 may be provided for providing one or more signals for actuating the system 10.

A switch 18 is provided in the system 10 for completely disabling the system 10 when the loads 12 are not to be actuated. In addition, this switch 18 is effective to allow the system 10 to function in response to a signal from the control means 16 whereby the loads 12 will be electrically energized from the battery '14 and/or control signals from the control means 16.

The present switch 18, as best seen in FIGURE 1, includes an outer protective housing 20. The housing 20 has a center or barrel portion 22 and a motor mount 24 that projects downwardly from the barrel 22.

The barrel 22 is hollow so as to have a passage 26 extending therethrough. However, a partition or bulkhead 28 extends across the passage 26 to divide it into two separate portions or

volumes

30 and 32. For reasons that will become apparent subsequently, this bulkhead 28 is electrically conductive and is formed integral with the rest of the housing 20.

The left end of the barrel 22 (as seen in FIGURE 1) forms an input while the right end forms an output. Although the housing 20 may be fabricated from any desired type of material, for reasons that will become apparent subsequently, it has been found desirable for the housing 20 to be formed of an electrically conductive material such as aluminum.

The input end is adapted to receive an inner input in sert 34. The insert 34 snugly fits inside of the barrel 22 and is normally relatively rigid whereby it will not be readily distorted out of shape. In addition, the insert 34 is normally a dielectric or electrically non-conductive member.

An input shell 36 fits into the end of the barrel 22 so as to engage the end of the insert 34. The shell 36 will thereby help to clamp the insert 34 in position. It has been found desirable to provide a resilient sealing member such as an O-ring 38 between the shell 36 and barrel 22. It has also been found desirable to provide a resilient seal 40 that fits inside of the shell 36 and abuts against the end of the insert 34. A second or outer insert 42 may be provided which. fits inside of the shell 36 so as to compress the seal 40 between the two inserts 34 and 42. This seal 40 in combination with the O-ring 38 will completely seal the input to the housing 20.

A plurality of electrical contacts such as electrical connectors 44 may be mounted in the two inserts 34 and 42. The connectors 44 are in the form of pins 45 and 45' having enlarged heads 46 and 46' and reduced extensions or shanks 4% or 48. The enlarged heads 46 and 46 are burried between the inserts 34 and 42 and the seal 40 while the shanks 48 and 48' project from the opposite sides thereof. Thus, although the shanks 48 are disposed inside of the input shell 36 they are still exposed.

A suitable connector plug 50 may be provided which is adapted to fit onto the shell 36 and be securely fastened thereto. The plug 50 includes a dielectric support member 52 having a plurality of electrical sockets 54 positioned in alignment with the connectors 44. When the plug 50 is in position, the sockets 54 receive the shanks 48 on the ends of the pins 45 and form an electrically continuous circuit therebetween. The sockets 54 are electrically connected to electrical conductors or wires in a cable 56 or similar device. The wires in the cable 56 are, in turn, connected to the control means 16 and/or power supply 14.

The second set of pins 45' are similar to the first set and include enlarged heads 46 and shanks 48' that project from the face of the insert 34 and extend axially of the housing. For reasons that will become apparent subsequently, it has been found desirable under some circumstances to provide means for limiting the current. In the present instance, this is accomplished by means of a resistor 58 disposed inside of the insert and connected between the two

heads

46 and 46. The value of the resistors 58 will, of course, depend upon the particular application. However, they are normally of just sufiicient magnitude to limit the current to a safe operating range.

The output end of the housing 20 is very similar to the input end and is adapted to receive an output shell 60. The junction therebetween is sealed by means of an O-ring 62. An inner insert 64, a resilient seal 66 and an outer insert 68 are all mounted in the output shell 60 similar to shell 36 on the input end. When the shell 60 is disposed in the fully assembled position the insert 64 will be forced against the bulkhead 28 and the intermediate seal 66 will be compassed sutficiently to form a tight seal that prevents any moisture entering the housing 20.

A plurality of connector pins 70 are disposed within the inserts 64 and 68. In the present instance, each of the connector pins 70 are aligned with one of the input connectors 44. The inner ends of the pins or socket contacts 70 are hollow to provide passages 72 aligned with openings 74 in the bulkhead 23. The outer ends of the connectors or socket contacts 70 are also hollow so as to form sockets 76. These sockets 76 are exposed through openings in the insert 68 so as to receive pins 78 on a connector plug 80 which is adapted to fit onto the output shell 60 and become securely fastened thereto. Each of the pins 78 is connected to electrical conductors 82 that lead to the electrical loads 12.

These conductors 82 may be included in a single cable or may be in the form of separate wires as shown. However, in either event, shielding 144 is normally provided to prevent incident electromagnetic energy from creating stray currents in the conductors 82 or in the loads 12.

In order to make and break the electrical connections between the input connectors 44 and output contacts 7 ii, a plurality of moveable contacts 84 may be provided inside of the housing 20. In the present instance, the contacts 84- are a plurality of pins that are mounted on a traveler 86 disposed inside of the barrel 22 for movement between the insert 34 and the bulkhead 28 or insert 98 if it is provided in front of the bulkhead. The traveler 86 includes a pair of blocks of a dielectric or electrically non-conductive material. The exterior of the blocks 90 may be substantially cylindrical so as to slide axially along the interior surface of the barrel 22. The traveler blocks 90 are slideably disposed upon guides 88 whereby they move in a substantially straight line axially of the housing 20 and between the opposite ends of the open space 3!).

Separate contacts 84 are provided for each input and

output connector

44 and 70. The contacts 84 which are mounted on the traveler blocks 90 for movement therewith are in the form of pins having enlarged heads 92 and elongated shanks 94. The heads 92 are anchored between the two blocks 90 and cannot move therefrom. However, openings 96 are provided inside of the heads 92 and in the blocks 90 in alignment with the shanks 48. The shanks 48 project into and slideably engage the surfaces of the passages 96. The lengths of the shanks 48' and the passages 96 in the heads 92 are at least equal to the travel of the traveler 86 whereby the traveler 86 can move from one end of the open space 30 to the other end while still maintaining an electrical path between the connectors 44 and the heads 92.

The shanks 94 of the pins project from the face of the blocks and are aligned with the openings formed in the bulkhead 28 and the sockets 72 inside of the second set of connectors 70. When the traveler 86 is in the retracted position (as shown in FIGURE 1), the ends of the shanks 94 will be retracted from the second connectors 70 so as to be electrically isolated therefrom. However, in addition, the shanks 94 are withdrawn from the openings 74 and completely outside of the electrically conductive bulkhead 28.

When the traveler 86 moves to its opposite extreme position it is positioned immediately adjacent the insert 98. The projecting ends of the shanks 94 will then extend through the openings 74 in the bulkhead 28 and into the passage 72 inside of the electrical connectors 70. It can be appreciated that under these circumstances, a continuous electrically conductive path will be established between the input connectors 44 and the output connectors 70. In order to assist in the movement of the shanks 94 through the bulkhead 23 and into and out of the passages 74, and to prevent electrical shorting, a suitable guide insert 98 is provided. This insert 98 consists of an electrically nonconductive material having a low coefiicient of friction. The guide 98 is mounted on the exposed side of the bulkhead 28 so as to support the ends of the shanks 94 even when they are retracted. In addition, the guide 98 includes sleeves 100 that project through the bulkhead 28 in substantial alignment with the sockets 72.

It will be noted that when the traveler 86 is in the retracted position, there will be an electrical discontinuity between the input circuitry and the output circuitry, and it will be impossible for any electrical signals to pass from the input circuitry to the output circuitry. Moreover, the ends of the shanks 94 are separated from the connectors 70 by the electrically conductive bulkhead 28 whereby they are effectively shielded from each other. When the traveler 86 is moved into the extended position, an electrically conductive path is formed between the input and output.

In order to move the traveler 86 from one extreme position to the other extreme position, any suitable form of drive motor may be provided. However, it has been found that there are numerous advantages to employing a suitable spring motor.

In the present instance, a spring motor 102 is mounted inside of the motor mounting 24 projecting from the barrel 22. The motor 102 includes a driveshaft 104 and a helical or spiral coil spring 107. The outer end of this spring 107 is anchored to the motor mount 24 and locked in a fixed position. The inner end of the spring 107 is connected to the driveshaft 104 so as to apply a torque thereto. The driveshaft 104 is supported by a pair of ball bearings 106 which are mounted on the inside of the motor mount 24. The shaft 104 will thus rotate inside of the mounting 24 as a result of the spring unwinding.

The upper end of the driveshaft 104 is drivingly connected to the traveler 86. In the present instance, this connection includes an eccentric crank 108 anchored on the driveshaft 102, a pin 110 on the traveler 86 and a link 112 which extends therebetween.

As can be seen from FIGURES 1 and 4A, when the spring 107 is fully wound or cocked the crank 108 will be in the far left position. The link 112 will thereby carry the traveler 86 to the far left or retracted position. A bolt or keeper 114, as best seen in FIGURES l and 3, is slideably mounted in a carrier 116 in the motor mount 24. When the keeper 114 is raised it engages an arm 118 on the shaft 104 whereby the traveler 86 is locked in the retracted position.

When the driveshaft 104 turns through approximately 180 degrees of rotation, the crank 108 will move into the position shown in FIGURE 4B whereby the traveler 86 will be in the extended position. The contacts 84 will then move and carry the shanks 94 through the bulkhead 28 whereby the contacts will be closed.

A second keeper 120 may be mounted in the carrier 116 so as to engage the arm 118 and retain the traveler 86 in this extended position. When the driveshaft 104 turns through approximately a second 180 degrees, the crank 108 and the link 112 will be in a position similar to that in FIGURE 4C. This will cause the traveler blocks 86 to be pulled back or returned to the retracted position whereby the contacts will separate and break the electrical circuits.

The two

keepers

114 and 120 are mounted on a carrier 116 which is adapted to be moved axially into and out of the motor mount 24 by means of an access opening 122. A cover 124 is removeably secured to the lower end of the motor mount 24 so as to close the access opening 122. The

keepers

114 and 120 are reciproca'bly mounted on the carrier 116 so as to be free to slide vertically up and down. As previously described, when the

keepers

114 and 120 are in the raised position their upper ends engage the arm 118 and prevent further rotation of the shaft 102 as described above. Thus, even though the spring 107 is fully wound the driveshaft 104 will not rotate. However, when the first keeper 114 is released, i.e., moved to its lowered position, the arm 118 will be free to pass over the top of the first keeper 114 and swing until it engages the second keeper 120. When the second keeper 120 is lowered the arm 118 will then swing until it engages the stop 126.

Although the operation of the keepers 114 and can be controlled in any desired manner, in the present instance the

keepers

114 and 120 are biased downwardly by separate springs 128. However, the

keepers

114 and 120 are normally maintained in the raised position by means of a sutiable release mechanism. Each of the present release mechanisms include a laterally projecting arm or 132 on the

keeper

114 or 120. Electrically conductive wires 134 are attached to pairs of electrical contact pins 136 and wrap around pins 138 on the blocks 140 on the arms 130 and 132. The wires 134 are preferably fabricated from a material having a high tensile strength to oppose the forces of the springs 128 and maintain the

keepers

114 and 120 in the raised position.

The electrically conductive pins 136 are mounted on the carrier 116 and are positioned to plug into sockets 142. These sockets 142 may be electrically energized by any suitable source capable of circulating an appropriate electrical current thereth-rough. Each of the wires 134 is adapted to function as a burn out element. Accordingly, they may be composed of a low melting resistive material such as commonly employed in electrical fuses. However, as previously stated, the wires 134 have a high tensile strength and may be fabricated from a material such as stainless steel. When an electrical current of sufficient magnitude flows through one of the wires 134, the wires 134 act as a short circuit and will very rapidly heat up. Although the wire may be heated sulficiently to cause it to melt and/or disintegrate, normally it will only heat to a temperature where its tensile strength decreases to less than the force from the spring 128. When this occurs, the wire separates and the block 140 is released. The spring 128 will then rapidly force the

keeper

114 or 120 downwardly whereby the arm 118 on the driveshaft 104 will be free to pass over the top of the

keeper

114 or 120.

As previously stated, for many applications the first keeper 114 is positioned to engage the arm 118 when the traveler 86 is in the fully retracted position similar to that shown in FIGURE 1. When the wire 134 separates, the first keeper 114 will release the driveshaft 104 whereby the driveshaft 104 will rotate until the arm 118 engages the second keeper 120.

The second keeper 120 is then positioned to engage the arm 118 when the traveler 86 reaches the other extreme position, i.e., the fully extended position. Under these circumstances, the contacts 84 will esablish an electrical circuit between the

contacts

44 and 70 so that a signal can flow from the control means 16 and/or battery completely through the switch 18 to the various loads 12. When a current fiows through the second Wire 134, it will separate and release the block 140. The second keeper 120 will then be driven downwardly by the spring 128 and the driveshaft 104 will again rotate in the same direction. This will cause the traveler 86 to again be moved into the retracted position whereby the electrical circuits will again be disrupted. The characteristics of the wire 134, the timing and the amount of current flow therethrough are selected to provide a time delay of some preselected amount. This will provide a dwell of suflicient duration to insure all of the loads 12 being completely energized before the circuit is again disabled. The plug 80 connnected to the output end of the switch 18 may be connected to a cable or a plurality of separate wires 82 for each of the connector pins 70. These wires 82 are, in turn, electrically connected to any uitable load that is to be actuated. These loads may be of any desired variety such as a relay, a motor, a pyrotechnic device for producing a visual display, or separating or destroying a physical structure. In order to prevent an accidental energizing of the loads 12 it has been found desirable to provide a shielding 144 around the loads 12 and around the electrical conductor 82. The

shielding 144 may be in the form of a flexible woven sleeve or a conduit. This shielding 144 is electrically connected to the swtich housing 20.

It will thus be seen that when the traveler 86 is in the retracted position, the connector pins 70, electrical conductors 82 and loads 12 are all included within a grounded shielded volume.

The moveable contacts 84 are physically separated and electrically shielded from the sockets 76 by the electrically conductive partition 28.

Thus, if there is any electromagnetic energy of even a high intensity level in the area surrounding the control system, it will be completely blocked from entering into any portion of the circuit which might energize one or more of the loads 12. In the event that there is a current induced in any of the unshielded portions of the circuit, these currents will not be coupled into the load portion of the circuit. More particularly, since the shanks 9d of the moveable contacts 84 are separated from the output pins 70, there will be an electrical discontinuity which will completely block the flow of any current. In addition, since the electrically conducted bulkhead 23 separates the various fixed and

moveable contacts

70 and 84, this bulkhead 28 will also form a shield which will prevent any radio frequency electromagnetic energy from being coupled across the gap separating the moveable and fixed contacts.

It is to be noted that the bulkhead 28 does have numerous openings 74 aligned with the pins 94 and sockets 72. If the pins 94 act as radiators, the openings 74 may act as waveguides and carry electromagnetic energy therethrough to the connectors 72. However, the dimensions of these openings 74 are relatively small and any energy that might propagate therethrough would be of an ex tremely high frequency. As a practical matter, any electromagnetic energy that is normally encountered is far below the cut-01f frequency of the waveguide capabilities. As a consequence, the openings 74 will act as wave traps and prevent the passage of any such energy. If it is desired to increase this effect, the lengths of the openings 74 may be increased to form a more complete trap.

It can be seen that the volume of the circuit that is shielded is greatly reduced. This, in turn, reduces the cost, bulk and Weight of the shielding while at the same time increasing the effectiveness of the shielding. In order to avoid the accumulation of a static charge within the shielded portion of the circuit, it has been found desirable to provide a high resistance path to ground. This may be accomplished by means of leakage resistors 147 connected between the pins 70 and the housin 20.

In order to employ the present invention, the input plug 50 is connected to the input end of the switch 18 and the output plug 80 is connected to the output end of the switch 18. The switch may be armed or set so as to retain the traveler 86 in the retracted position. In order to accomplish this, the cover 124 on the lower end of the motor mount 24 may be removed from the access opening 122 so as to expose the interior of the mount. The carrier 116 may be then disconnected and pulled downwardly through the access opening 122, and removed from the mounting 24. When the carrier 116 has thus been removed, the plugs will be disconnected from the sockets 142 and the

keepers

114 and 120 in the various lock mechanisms will be removed therewith.

Following this, the

keepers

114 and 120 are moved to the raised or extended position and a new set of keeper or burn out wires 134 installed. This will maintain the keepers in the raised position against the forces of the springs 128. Following this, the driveshaft 104i is rotated so as to retract the traveler 86 and position the arm 118 behind the first keeper 114. Following this, the carrier 116 is again inserted through the access opening 122 and into the motor mount 24. The pins 136 will then fit into the sockets 142 whereby the electrical burn out wires 134 will again be electrically connected to the circuit. The first keeper 114 will now engage the arm 118 and retain the driveshaft 1&4 in the fully wound position.

The system 10 is now ready for energizing the loads 12 in response to a control signal supplied to the first burn out lire 134. Although this signal may be provided in any desired manner, in the present instance a pair of electrical conductors 146 are connected to the sockets 142, and extend through the input insert 34 to a pair of connectors 148. These connectors 148, in turn, are adapted to be contacted by sockets Ed in the input plug for interconnection with the control means 16.

When it is desired to energize the loads 12, the control means 16 may supply a suitable actuating current which flows through the contacts 148, the conductors 146 and the sockets 142 so as to short circuit through the first burn out wire 134. As soon as a sufiicient amount of current has flowed through this burn out wire 13 the burn out Wire 13 3 will separate and release the first keeper 114. As soon as the keeper 114 has dropped into the position shown in FIGURE 1, the arm 118 will be free to rotate due to the torque from the spring 167. The arm 118 will then swing until it hits the upper end of the second keeper 129. At this point, the linkage 112 will be substantially as shown in FTGURE 4B, and the traveler 86 will have moved against the guide insert 98. The shanks 94 will then extend into the output connector pins 76 whereby a circuit will be established from the control means 16 to the various loads 12 whereby the loads 12 will be energized. The resistors 58 will limit the maximum amount of current the loads 12 can draw.

After the loads 12 have been actuated, it is desirable to break the electrical circuit and prevent further operation of the load and/or additional drain on the power supply or battery 14. Normally, the loads 12 will only be energized for a limited period of time. Accordingly, the second burn out wire 134 may be energized after the lapse of a suificient dwell time to insure that all of the loads 12 have been energized. In the present instance, this is accomplished by placing the second burn out wire 134 in a circuit parallel to the first burn out wire 134. This circuit includes conductors 156, contacts 152 and shorting bar 154. When the traveler 86 is at its far right position a circuit flows through 134. The second magni tude of this current and the characteristics of the burn out wire 134 may be selected so that an appropriate time delay or dwell time will be provided before the burn out wire 134 actually separates. After the wire 134 separates, the second keeper will be released so that the arm 11% will again be free to pass over the second keeper 120 and rotate into and against the stop 126. The linkage 112 will now be moved into the position shown in FIGURE 4C, and the traveler 86 will again be moved to the retracted position whereby the shanks 94 will be separated from the heads of the output connectors 70. Thus, the loads 12 will again be completely sep arated from the control means 16 and/or power supply 14.

Although the foregoing embodiment has been found effective, under some circumstances it may be desirable to employ the embodiment shown in FIGURE 5. This embodiment 16% is substantially identical to the preceding embodiment except that the motor mount 162 is secured to the barrel of the housing 164, by a plurality of bolts 166 rather than being integral therewith. This will permit the motor mount 162 being removed from the switch 156 without in any way disturbing the switch and its electrical interconnection with the rest of the circuit 10. Accordingly, the motor mount 162 may be removed and the various keepers, burn. out wires, etc. arranged in a cocked or loaded position. Thus, as soon as the switch 18 has been actuated, the motor mount 162 may be replaced with another motor which was previously fully armed. In addition, the circuitry for actuating the various burn out wires may be included in the motor mount 162 so that they can be separately interconnected with the control means by conductors 168 for energizing the burn out wires totally independent of the circuitry for energizing the various loads.

As a further alternative, the embodiment 170 of FIG- URES 6 and 7 may be employed. This embodiment 170 employs a susbtantially cylindrical housing 172 having a passage 174 extending axially therethrough. Various dielectric inserts 176 may be inserted through the opposite ends of the housing 172 for supporting input and

output connector contacts

178 and 180. In addition, a dielectric traveler 182 may be disposed inside of the housing 174 for moving axially thereof between two extreme positions adjacent the first or second input inserts 176.

A separate hollow contact 184 for each set of input and output contacts may be mounted on the traveler 182 so as to move therewith. This contact 184 has an axial passage extending therethrough which is adapted to slide upon the shanks of the input and output connectors 17S and 180. When the traveler 182 is in the extreme position shown in FIGURE 7, the contact 184 will be separated so that the circuit will be electrically discontinuous.

In order to assure a complete disconnecting of the load 12 and prevent an accidental energizing thereof, a bulkhead or electrically conductive shield 186 may be provided across the end of the output inserts 176. This shield 186 has a separate opening 188 for each of the connectors 180. The shank 199 of the output connector 180 extends through the openings 188 in the shield 186. In addition, the shield 186 may include a tubular extension 192 which is adapted to ride against the exterior surface of the moveable contact 184 only when the traveler 182 is positioned in the open position such as shown in FIGURE 7. It will be appreciated that this will be effective to ground each and every one of the output connectors 180 so that it will be impossible for a sufiicient curernt to be created in the output circuit to energize the loads 12.

In order to move the traveler 182 between its various positions, a motor similar to the preceding motor 162 may be employed. However, in this particular instance, a cam 194- is employed instead of the linkage. As the cam 19 d rotates it will be effective to move the traveler 182 from one extreme position into the other extreme position, and then if desired, return it to the original extreme position. In addition, a spring 196 and guide 198 may be provided to assist in the movement of the traveler 182 from one extreme position to the other.

From the foregoing description it can be seen that if there is stray electromagnetic energy present in the vicinity of this electrical circuit, the shielding will prevent the inducing of stray currents in the output circuitry. Although similar currents may be induced in the input circuitry, these signals will not be able to pass from the movable contacts to the fixed contacts. If there are high frequency currents in the unshielded or input section, they will not be coupled into the output section because of the intervening conductive bulkhead or partition.

Although only a limited number of embodiments of the present invention are disclosed herein, it will be readily apparent to persons skilled in the art that numerous changes and modifications may be made thereto without departing from the spirit or" the present invention. Accordingly, the foregoing disclosure and description there of are for illustrative purposes only, and do not in any way limit the scope of the present invention which is defined only by the claims which follow.

We claim:

1. An electrical switch including the combination of an electrically conductive switch housing,

a set of fixed electrical contacts disposed inside of the housing,

a set of moveable contacts disposed inside of the housing and moveable between a first position wherein the moveable contacts are separated from the fixed contacts, and a second position wherein the moveable contacts electrically engage the fixed contacts,

an electrically conductive partition in said housing dividing said housing into two separate volumes that are shielded form each other by the partition, said partition being disposed between the sets of contacts when the moveable contacts are in the first position so as to shield them from each other, said partition including openings aligned with the contacts in said set whereby the moveable contacts extend through the partition when in the second position, and

means for moving the moveable contacts between the I first position and the second position.

2. An electrical switch including the combination of an electrically conductive switch housing,

an electrically conductive partition drividing said housing into two separate volumes that are shielded from each other by the partition,

a set of fixed contacts in the first of said volumes and separated from the second of said volumes by the partition,

a set of contacts moveable between a first position wherein the moveable contacts are disposed in the second volume and electrically separated from the fixed contacts and a second position wherein the moveable contacts extend through the partition and between the two volumes and electrically interconnect with the fixed contacts,

a drive motor on said housing, and

means coupling said motor to the moveable contacts for moving said contact between said positions.

3. An electrical switch including the combination of an electrically conductive switch housing,

an electrically conductive member in said housing dividing said housing into two separate volumes that are shielded from each other by the member, said member including a plurality of restricted openings,

a first set of electrical contacts disposed in one of said volumes, in substantial alignment with said openings,

21 second set of electrical contacts disposed in the other of said volumes in substantial alignment with said openings, said member and said housing enclosing the second volume and shielding the volume and the contacts therein from electromagnetic energy, and

the contacts in one of said sets being moveable between a first position and a second position, said movable contacts when in the first position being disposed inside of its respective volumes and shielded from the fixed contacts in the other volume, said moveable contacts when in the second position extending through the openings in said member and into the second of volumes and electricallyv interconnecting the contacts in both sets.

4. An electrical switch including the combination of an electrically conductive switch housing,

an electrically conductive member in said housing and dividing said housing into two volumes that are shielded from each other by the member,

a first set of fixed contacts disposed in one of said volumes,

a second set of fixed contacts disposed in the other of said volumes and electrically separated from the first set of contacts,

a set of moveable contacts disposed in said housing and moveable between a first position and a second position, said moveable contacts when in the first position being disposed in the first volume and shielded from the contacts in the second set by said member, said moveable contacts when in the second position extending through said member and interconnecting the fixed contacts in said sets.

5. An electrical switch including the combination of a first set of fixed electrical contacts,

a second set of fixed electrical contacts,

moveable contact means disposed between said sets of fixed contacts for movement between a first position wherein the fixed contacts are electrically disconnected and a second position wherein the moveable contact means interconnect the fixed contacts, and

at least one detent means coupled to the moveable contact means for retaining the moveable contact means in one of said positions, said detent means including an electrically conductive burn out wire that is stressed when said moveabie contact means is in said position, said wire being etlective to break and release said moveable contact means when a current flows therethrough and heats said wire beyond a predetermined temperature.

6. An electrical switch including the combination of a switch housing,

a first set of electrical contacts in said housing,

a second set of electrical contacts in said housing,

moveable contact means disposed in said housing and moveable between a first position and a second position, said moveable contacts when in the first position disconnecting said fiixcd contacts and when in the second position interconnecting said fixed contacts,

spring load drive means in said housing and coupled to said moveable contact means to move said contact means from one of said positions to the other of said positions,

a first detent including an electrically conductive wire coupled to said means and stressed by the spring load drive means for retaining the contact means in one of said positions, and

a second dctent including an electrically conductive wire coupled to said means and stressed by the spring load drive means for retaining the contact means in the other of said positions, each of said wires being effective to separate and release said means when heated by an electrical current.

7. An electrical switch including the combination of a switch housing,

a first set of fixed electrical contacts in said housing,

a second set of fixed electrical contacts in said housing,

moveable contact means disposed in said housing and moveable between a first position wherein the fixed contacts are electrically disconnected and a second position wherein the fixed contacts are electrically connected,

spring loaded drive motor means coupled to the moveable contact means for moving said contact means between the first and second positions, and

a detent including an electrically conductive wire coupled to said means stressed by said drive motor means and effective to retain the moveable contact means in one of said positions, said wire being responsive to an ele;trical current and efiective heat up to a sulficient temperature to separate and break by said stress and release said means.

8. An electrical switch including the combination of a switch housing,

at least one set of fixed contacts on said housing,

a set of contacts disposed on said housing and moveable between a first position and a second position, said moveable contacts when in one of said positions being disconne:ted from the fixed contacts and when in the other of said positions being connected to the fixed contacts,

a one-way spring motor in said housing having a driveshaft that rotates in one direction, and

an overcenter drive linkage coupling the driveshaft to said moveable set of contacts, said linkage being effective to move the set of moveable contacts from one of said positions to the other of said positions when said driveshar't rotates a predetermined amount in one direction and to move overcenter and retract the set of rnoveable contacts from said other of said positions back to said one position when the driveshaft continues to rotate in the same direction.

12 9. An electrical switch including the combination of a switch housing, a first set of fixed contacts on said housing, a second set or"; fixed contacts on said housing, a set of contacts disposed on said housing and moveable between a first position and a second position, aid moveable contacts when in one of said positions disconnecting the fixed contacts in the fixed sets and when in the other of said positions interconnecting said fixed contacts in said sets, a one-way spring motor, and overcenter means coupling said spring motor to said moveable set of contacts for moving said contacts from the first position to the second position and to return contacts to the first position while said notor runs in the same direction. it An electrical system of the class described including the combination of at least one electrical load effective to be actuated in response to an electrical signal, electrically conductive means having a first portion interconnect and with the loads for supplying signals thereto and forming a first set of contact means, electrical shielding means surrounding said portion and the contact means in said first set, said shielding including openings aligned with said contact means, a signal source for supplying signals for energizing the loads, said electrically conductive means having a second portion disposed outside of the shielding means, said second portion being coupled to said signal source and forming a second set of means disposed outside of said shielding and aligned with the openings, and switch means moveable between a first position wherein the first set of contacts are separated from the second set of contact means by said shielding means and a second position wherein at least one of said sets of contact means extends through the openings in said shielding means and engages the other set of contact means. 11. An electrical system of the class described including the combination of at least one electrical load efiective to be actuated in response to an electrical signal, a signal source etlective to provide an electrical signal for actuating said load, a switch having an electrically conductive housing, electrically conductive means having a first portion interconnected with the signal source and forming a first set of contacts in the switch housing, said electrically conductive means having a second portion interconnect d with the load and forming a second set of contacts in the switch housing, electrically conductive shielding means enclosing and shielding the second portion including the second set of contacts, said shielding means including an electrically conductive partition between said sets of contacts, said conductive partition including a plurality of openings aligned with the contacts in said sets, and one of said sets of contacts being moveable between a first position and a second position, said contacts when in the first position being separated from the contacts in the other set by the conductive partition, said moveable contacts when in the second position extending through the openings in said partition and contacting the contacts in the other sets whereby said first and second portions of the electrically conductive means are interconnected. 12. An electrical system of the class described including the combination of at least one electrical load effective to be actuated in response to an electrical signal, a signal source effective to provide an electrical signal for actuating said load,

electrically conductive means interconnecting the source with said loads for coupling electrical signals from the source to the load,

switch means in said electrically conductive means, said switch means having an open condition dividing said conductive means into a first portion including the signal source and a second portion including the load, said switch means having a closed condition wherein the first portion and second portion are joined, and

means shielding the second portion from external electromagnetic radiations and from the first portion when said switch is in the open condition.

13. An electrical switch for blocking the passage of electromagnetic energy, said switch including the combination of an electrically conductive switch housing,

a fixed set of electrical contacts disposed inside of the housing,

a second set of contacts disposed inside of the housing,

one of said sets being moveable between a first position wherein the contacts in said sets are separated from each other, and a second position wherein the contacts in said sets are in electrical engagement with each other,

an electrically conductive bulkhead in said housing dividing said housing into two separate volumes that are shielded from each other by the bulkhead, said bulkhead being disposed between the sets of contacts when the moveable contacts are in the first position so as to shield the contacts in said sets from electromagnetic energy being radiated between the contacts in said sets,

a plurality of waveguides extending through the bulkhead, said waveguides being aligned with the contacts in said sets whereby the moveable contacts extend through the waveguides when in the second position, the waveguides being constructed and arranged to have a cut-off frequency that is above the frequency of the electromagnetic energy, and

means for moving the moveable contacts between the first position and the second position.

References Cited UNITED STATES PATENTS 2,110,171 3/1938 Peters 200-l66 2,805,579 9/1957 Dehn 200153 2,938,976 5/1960 Wilson 20082 H. BURKS, Assistant Examiner.