GB1601769A

GB1601769A - High vacuum electrical sockets

Info

Publication number: GB1601769A
Application number: GB23731/78A
Authority: GB
Original assignee: MAN Maschinenfabrik Augsburg Nuernberg AG; Souriau Electric GmbH
Current assignee: Souriau Electric GmbH; MAN AG
Priority date: 1977-06-08
Filing date: 1978-05-30
Publication date: 1981-11-04
Also published as: FR2394192A1; FR2394192B1; DE2725796C2; NL185045B; JPS5439896A; NL7806106A; DE2725796A1; NL185045C

Description

(54) IMPROVEMENTS IN OR RELATING TO HIGH VACUUM ELECTRICAL SOCKETS (71) We, MASHINENFABRIK AUGSBURG NURNBERG AKTIENGESELLSCHAFT, a Company of the Federal Republic of Germany of Postfach 50 06 20, 8000 Munchen 50, Germany and SouRzAu-ELEcTRIc GmbH., a a Company of the Federal Repulic of Germany of Heinrich-Hertz-Strasse 1, 4006 Erkrath 1, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a high-vacuumtight electrical socket having contact pins anchored in a casing.

It is well known that sockets of this kind are made from a metal casing in the form of a bush with an integrally moulded flange, contact pins being inserted into the casing and the intermediate space being filled with glass balls. The glass, which is subsequently fused in, encloses the contact pins in their central zone and forms a vacuum-tight base on the end of the metal bush adjacent the flange. Although such known sockets are high-vacuum-tight and also vacuum-resistant, they have the disadvantage that, due to the brittle properties of glass, parts can readily break away when the apparatus is handled and the socket may become leaky. The production of such sockets also requires a number of operations due to the heat treatment.

An object of the invention is to develop a high-vacuum-tight electrical socket having contact pins anchored in a casing, so that it can be readily produced while complying with safety regulations.

To this end, according to the invention, the casing consists of high-vacuum-resistant thermoplastics and is formed as a single moulding with a sealing flange and the contact pins extend through the casing and have a labyrinth in each case in the zone where they extend through the casing.

This provides a high-vacuum-tight vacuumresistant socket of high mechanical strength, which is also temperature-resistant and has good insulating properties. The casing can be produced by injection moulding or casting and, if necessary, be machined subsequently.

The strength and the elasticity of a socket in which this invention is embodied can also be adapted to requirements at any time by appropriate selection or composition of the, thermoplastic material, The contact pins are recessed directly into this material and anchored firmly therein and secured against axial displacement as a result of the labyrinth. The labyrinth also extends the contact surface between the contact pins and the thennoplastic material so that high yacuum-tightness is ensured.

A socket of this kind can be cast or injection moulded in one operation. The boreholes for fixing means and, if required, grooves to receive ring gaskets, can be moulders in at the same time as the casing is formed.

In a preferred embodiment of the invention, the socket may be in the form of a bush and have at least two slots to receive engagement lugs of an associated plug, while the slots may have recesses into which the lugs of the plug engage with a snap action in the end position. This ensures that the socket has a secure and easily made connection whereby the plug can be inserted in the correct position without damaging the contact pins. If the contact pins are disposed asymmetrically, it is advantageous additionally to provide a guide groove which does not allow the plug to be inserted until the two parts of the connector are in the correct relative orientation.

According to a further feature of the invention, if polycarbonate is used for the casing it is possible to achieved vacuumtightness up to 10-9 Torr 1 sec-1. This material has a softening point at 100;C and has adequate insulating properties up to 500 volts.

One form of connector which comprises a high-vacuum-tight socket in which this invention is embodied and a cooperating plug will be described now by way of example with reference to the-accompanying drawings, of which: Figure 1 is a partially sectioned side -ete- vation of the socket; Figure 2 is a partially sectioned side elevation of the plug which cooperates with the socket shown in Figure 1; and Figure 3 is an underneath plan view of the socket shown in Figure 1.

Figure 1 shows that the socket 12 comprises a casing in the form of a bush 10 and a flange 11. The flange 11, the bush 10 and the base 13 of the bush are made as an integral moulding from a high-vacuum-resistant thermoplastics material. Contact pins 1W18 having labyrinths in the form of rings 19 extend through the base and are hermetically enclosed therein by the casting or injection moulding process used for the production of the casing. As a result of the labyrinth 19, the contact surface between the two sides of the base 13 at the contact pins is so lengthened that high vacuum-tightness is also achieved. Another advantage of the labyrinth is that the pins 1X18 are anchored rigidly in the base 13 of the casing and can be subjected to axial loading.

The socket 12 is fitted to a vacuum tank or machine with the top surface 20 (as seen in Figure 1) of the flange 11 seated thereon, and is connected thereto by fixing means, e.g. screws, passing through boreholes 21. Sealing is effected by a ring gasket (not shown) fitted into an annular groove 22.

The outwardly projecting bush 10 of the socket serves to receive the plug 25 shown in Fig. 2. The bush 10 has two slots 26 and the plug 25 has two corresponding lugs 27.

To connect the two parts, the plug 25 is pressed into the socket 12, the slots 26 being opened slightly, until the lugs 27 engage with a snap-action in corresponding recesses 30. A connection of this kind cannot be disconnected without the application of some force sufficient to open up the two halves of the bush slightly. This snap-action connector also has the advantage that a reliable and secure fit of the two parts is always possible if the length A on the free end of the bush 10 is somewhat longer than the distance B between the lugs 27 and the end face of the plug 25. If the orientation of the two parts is incorrect, the lugs 27 abut the free edge of the bush 10 so that it is not possible for the end- face of the plug 25 to reach one of the contact pins or bend it over.

For asymmetric contact pins 1g18 a guide groove 32 is provided in the plug 25 while the other part of the connector that is the socket 12 has a corresponding guide nose 33 (see Figs. 2 and 3). This arrangement ensures that the tubular contact pins 37 of the plug 25 can receive the contact pins 14--18 of the socket 12 only when they are exactly in register. The connector can thus be reliably and securely connected even if it is so disposed on a unit as to be accessible only invisibly. The earth contact pin 15 is advanced as another safety precaution i.e. so that the earth connection is made before contact is made between pins which are connected to phrases and other electrically conductive parts.

In order finally further to simplify assembly of a socket 12 in which this invention is embodied, a metal plate 35 is also recessed into the socket mould to enclose a fixing borehole 21 and is connected with the earth contact pin 15. In this way connection to earth is made directly via the screw by means of which the socket 12 is fixed to a tank, motor, or some other apparatus.

To secure the connection leads 38 of the plug 25, the plug 25 has longitudinal grooves 39 into which the leads 38 are clamped by a cable grip 40. In this way the plug connection is secured even in relation to traction applied to the leads 38.

The plug and socket connection described above with reference to and illustrated in the accompanying drawings is described and claimed in the Complete Specification of our co-pending Patent Application No. 25878/78 serial no. 1601770 which claims a pug and socket connection for a pair of inter-engaging electrical holders of electrically insulating material, wherein part of a first of the holders is in the form of a hollow cylinder and has at least two slots each with a recess formed in it, and the second contact holder is adapted to be plugged with guidance into the hollow cylindrical part of said first holder and has lugs which are adapted to be inserted into the slots of said first contact holder and to be engaged in the corresponding recesses with a snap-action when the second contact holder is plugged into the hollow cylindrical part of said first contact holder and the plug and socket connection is made.

WHAT WE CLAIM IS: 1. A high-vacuum-tight electric socket having contact pins anchored in and extending through a casing which consists of highvacuum-resistant thermoplastics, each contact pin having a labyrinth in the zone where it extends through the casing, and the casing being formed as a single moulding with a sealing flange.

2. A socket according to claim 1, wherein the casing comprises a bush and has at least two slots to receive engagement lugs of an associated plug.

3. A socket according to claim 2, wherein the slots are provided with recesses which are adapted to receive the engagement lugs with a snap action.

4. A socket according to claim 2, wherein a longitudinally extending guide groove or nose is provided in the socket bush and is adapted to cooperate with a corresponding guide nose or groove in an associated plug.

5. A socket according to any one of the preceding claims, wherein one of the contact

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Figure 2 is a partially sectioned side elevation of the plug which cooperates with the socket shown in Figure 1; and Figure 3 is an underneath plan view of the socket shown in Figure 1. Figure 1 shows that the socket 12 comprises a casing in the form of a bush 10 and a flange 11. The flange 11, the bush 10 and the base 13 of the bush are made as an integral moulding from a high-vacuum-resistant thermoplastics material. Contact pins 1W18 having labyrinths in the form of rings 19 extend through the base and are hermetically enclosed therein by the casting or injection moulding process used for the production of the casing. As a result of the labyrinth 19, the contact surface between the two sides of the base 13 at the contact pins is so lengthened that high vacuum-tightness is also achieved. Another advantage of the labyrinth is that the pins 1X18 are anchored rigidly in the base 13 of the casing and can be subjected to axial loading. The socket 12 is fitted to a vacuum tank or machine with the top surface 20 (as seen in Figure 1) of the flange 11 seated thereon, and is connected thereto by fixing means, e.g. screws, passing through boreholes 21. Sealing is effected by a ring gasket (not shown) fitted into an annular groove 22. The outwardly projecting bush 10 of the socket serves to receive the plug 25 shown in Fig. 2. The bush 10 has two slots 26 and the plug 25 has two corresponding lugs 27. To connect the two parts, the plug 25 is pressed into the socket 12, the slots 26 being opened slightly, until the lugs 27 engage with a snap-action in corresponding recesses 30. A connection of this kind cannot be disconnected without the application of some force sufficient to open up the two halves of the bush slightly. This snap-action connector also has the advantage that a reliable and secure fit of the two parts is always possible if the length A on the free end of the bush 10 is somewhat longer than the distance B between the lugs 27 and the end face of the plug 25. If the orientation of the two parts is incorrect, the lugs 27 abut the free edge of the bush 10 so that it is not possible for the end- face of the plug 25 to reach one of the contact pins or bend it over. For asymmetric contact pins 1g18 a guide groove 32 is provided in the plug 25 while the other part of the connector that is the socket 12 has a corresponding guide nose 33 (see Figs. 2 and 3). This arrangement ensures that the tubular contact pins 37 of the plug 25 can receive the contact pins 14--18 of the socket 12 only when they are exactly in register. The connector can thus be reliably and securely connected even if it is so disposed on a unit as to be accessible only invisibly. The earth contact pin 15 is advanced as another safety precaution i.e. so that the earth connection is made before contact is made between pins which are connected to phrases and other electrically conductive parts. In order finally further to simplify assembly of a socket 12 in which this invention is embodied, a metal plate 35 is also recessed into the socket mould to enclose a fixing borehole 21 and is connected with the earth contact pin 15. In this way connection to earth is made directly via the screw by means of which the socket 12 is fixed to a tank, motor, or some other apparatus. To secure the connection leads 38 of the plug 25, the plug 25 has longitudinal grooves 39 into which the leads 38 are clamped by a cable grip 40. In this way the plug connection is secured even in relation to traction applied to the leads 38. The plug and socket connection described above with reference to and illustrated in the accompanying drawings is described and claimed in the Complete Specification of our co-pending Patent Application No. 25878/78 serial no. 1601770 which claims a pug and socket connection for a pair of inter-engaging electrical holders of electrically insulating material, wherein part of a first of the holders is in the form of a hollow cylinder and has at least two slots each with a recess formed in it, and the second contact holder is adapted to be plugged with guidance into the hollow cylindrical part of said first holder and has lugs which are adapted to be inserted into the slots of said first contact holder and to be engaged in the corresponding recesses with a snap-action when the second contact holder is plugged into the hollow cylindrical part of said first contact holder and the plug and socket connection is made. WHAT WE CLAIM IS:

1. A high-vacuum-tight electric socket having contact pins anchored in and extending through a casing which consists of highvacuum-resistant thermoplastics, each contact pin having a labyrinth in the zone where it extends through the casing, and the casing being formed as a single moulding with a sealing flange.

pins is for connection to earth and is longer than the other contact pins.

6. A socket according to any one of the preceding claims, wherein there is an electrically conductive element which is connected to one of the contact pins which is for connection to earth, the element being adapted to be brought into contact with fixing means for the socket.

7. A socket according to any one of the preceding claims, wherein the thermoplastic material is polycarbonate.

8. A socket substantially as described hereinbefore with reference to the accompanying drawings and as illustrated in Figures 1 and 3 of those drawings.