US2075057A - Method of securing contact members - Google Patents

Description

March 30, 1937.

H. -K. RICHARDSON METHOD OF SECURING CONTACT MEMBERS Filed Oct. '7, 1933 0 07.0 5 1 0 1 Z Z 1 g Iv 6 a 5 4 1 6 1 5 1 7 9w 1 6 1 LPII. 4 I Z m Z 1-1 U1 -$PAK$|NM$ 4 Y 6 Z Patented Mar. 30, E93? Wires" sraras PATENT OFFIQE METHOD OF SECURING CONTACT MEMBERS Application October 7,

8 Claims.

This invention relates to the manufacture of electrical devices such as high wattage incandescent electric lamps, power tubes, rectiflers or other devices where contact elements are employed for the passage of heavy currents.

When making a high wattage incandescent electric lamp forexample, it is desirable, from an operative and practical standpoint to provide relatively large metallic contact pins and considerable difilculty has heretofore been encountered in sealing the pins in the glass wall of the bulb which forms part of the device.

It has been proposed to provide tubular contacts, termed thimble seals, preferably closed at one end and having the opposite end provided with a thin edged funnel shaped opening. These pins are sealed to the wall of a bulb by first beading the edges of the open ends with glass and then heating by means of gas flames to seal the bead to the edges of suitably disposed openings.

It is an object of the present invention to simplify the method of attaching contacts to a bulb wall.

Another object of the invention is to provide a method whereby a more uniform and effective union between a metallic edge and a glass wall is attained. Another object of the invention is to provide a method whereby a plurality of contacts may be simultaneously sealed to a bulb wall.

Other objects and advantages of the invention will be more clearly understood from the following description together with the accompanying drawing in which- Fig. 1 shows a portion of a bulb with contacts or thimbles sealed therein in accordance with the present invention;

Fig. 2 shows apparatus for holding a thimble in position to be sealed to a bulb wall and means for heating the glass;

Fig. 3 is a view similar to Fig. 2 but shows the g ass after it has been softened and sealed to the edge of a contact member; and

Fig. 4 is a modified form of apparatus for sealing a thimble to a bulb and in which the heater is disposed within the end of the thimble.

In devices of the character to which the present invention is most applicable a cup-shaped portion III of glass is provided. This cup is provided with contacts or thimbles II and is then sealed along edge l2 to a bulb l3 indicated in dotted lines. The cup may be provided with an exhaust tube It through which the bulb may be evacuated in the usual manner. Usually the cup is provided with support members to 'which 55 electrodes or resistance elements such as tung- 1933, Serial No. 692,587

sten filaments are secured. The cup may, therefore, be constructed to include the internal structure or operating elements of the device and a convenient method is, therefore, had for properly mounting the elements and for locating them within the bulb. When the cup is fused to the bulb the device is complete for the sealing-off operation.

. As above mentioned, it has heretofore been proposed to provide the thimbles with glass layers or beads to facilitate their gas-tight union with the bulb wall. In the present method, however, this beading is dispensed with.

The wall I5 of the cup is provided with apertures l6 of any desired number. The selected embodiment of the invention includes two such apertures since two contacts are to be used. Each aperture is provided with an outwardly extending tapered hollow boss or extension l1. This boss is so proportioned that it just enters the inner surface adjacent to a tapered edge 20 of a thimble l8. This thimble is flared and is integral with a tubular cylindrical portion I9 which serves as the contact proper and enters a socket for the passage of electrical energy through the device when in operation.

A support 2| having an aperture 22 may be provided to hold the contact element in position so that the boss I! maybe positioned as shown in Fig. 2. In accordance with the present invention a local heat zone isprovided to soften the glass boss and cause it to wet or stick to the edge 20 of the thimble. In the present construction a heat zone is created by means of a resistance element 22' in the form of a helical coil which surrounds the tapered edge 20 and the contacting glass boss 11. An insulative bafile 23 may be provided to confine the heat for the purpose intended when current passes through the coil. Any suitable source of current supply may be used and a switch 24 may be provided to open and close a circuit including conductors 25 and 26, attached to opposite ends of the coil or resistance element22. When the respective parts are in position and the glass boss has been heated to a sufficiently plastic state, a member 26 is moved downwardly against the inner edge of the aperture 16 to firmly press the glass against the edge 20v and effect a gas-tight seal.

' The member 26 is disposed with its vertical axis in alignment with the vertical axis of the contact members so that as pressure is applied to the member the contact pin is aligned with the axial line of the tubular boss or extension l1. Thus as heat is applied to soften the glass to permit -ittoflowontotheinnersurfaceofthecontact the member I. in conjimction with the support for the contact pin maintains the proper perpendicular relation of the pin with the wall II. In cases where exceptionally large contact members are employed a heater element 2! (see Fig.

boa ii is rendered plastic and wets with the an edge II and a gas-tight seal is produced. Ob-

viously, if found desirable, the structure shown in Pig. 4 may be provided with an external heater coil to provide a surrounding zone of heat to facilitate the sealing operation.

9,5 Although a preferred embodiment of the invention is shown and described herein,-it is to be understood that modifications may be made therein without departing from the spirit and scope of the invention, as set forth in the appended 30 claims.

I claim:

l. The method of securing a tubular member having an open end to a wall of a glass cup which comprises providing a cup with a tubular pro- 35 jection with one endof less diameter than the interior diameter at the open end of said member, positioning an edge of said tubular member adjacent to an end of the projection, creating a zone of heat about said edge to render plastic 4 the end of said projection and in forcing together said projection and said member to cause said plastic end of said projection to enter said member and intimately unite the glass with the interior wall of said member.

2. The method of sealing a tubular member to a glass body which comprises providing said body with a tubular projection, positioning the projection and member end-to-end, locally heating said ends until the glass end has been rendered 50 plastic and in moving the parts together while said glass is in a plastic state to cause said projection to enter said member and intimately contact with the inner surface thereof.

3. The method of sealing a tubular metallic 55 member to a glass body having a tubular projection which comprises, providing a tubular member with an open end having an inside-diameter slightly greater than the external diameter at the end of said projection, positioning said 50 member and projection in axial alignment and with their ends in close proximity, locally heatme said ends until the glass part becomes plastic and flows into said member in contact with the interior surface of said tubular member.

4. The method of sealing a tubular metallic member. to a glass body having a tubular projection which comprises, providing a tubular member with an open end having an inside diameter slightly greater than'the external diameter at the end of said projection, positioning said member and projection in axial alignment and with their ends in close proximity, locally heating said ends until the glass part becomes plastic and flows into the inner surface of said tubular member.

5. The method of sealing a tubular metallic member to a glass body having a tubular projection which comprises, providing a tubular member with an open endhaving an inside diameter slightly greater than the external diameter at the end of said projection, positioning said member and projection in axial alignment and, with their ends in close proximity, locally heating vsaid ends until the glass part becomes plastic and flows into and in contact with the interior surface of said tubular member, and in relatively moving said member and body.

6. The method of sealing a tubular metallic member to a glass body having a tubular projection which comprises, providing a tubular metallic member with an open end having an inside diameter slightly greater than the external diameter at the end of said projection, positioning said member and projection in overlapping relation and axial alignment, locally heating said ends until the glass part becomes plastic and flows into contact with the interior surface of said tubular member. 1

7. The method of sealing a hibular metallic member to a glass body having a tubular projection which comprises, providing a tubular metallic member with an open end having an inside diameter slightly greater than the external diameter at the end of said projection, positioning said member and projection in overlapping relation and axial alignment, locally heating said ends until the glass part becomes plastic and flows into contact with the interior surface of said tubular member, and in relatively moving said member and projection.

8. The method of sealing a tubular metallic member to a glass body having a tubular projection which comprises, providing a tubular member with an open end having an inside diameter slightly greater than the external diameter at the end of said projection, positioning said member and projection with the open end of said projection extending into the open end of said member, locally heating said ends until the glass part becomes plastic and flows into contact with the interior surface of said tubular member.

HENRY K. RICHARDSON.

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