US2513870A

US2513870A - Hermetically sealed crystal

Info

Publication number: US2513870A
Application number: US3939A
Authority: US
Inventors: Philip R Hoffman
Original assignee: REEVES HOFFMAN CORP
Current assignee: REEVES HOFFMAN CORP; REEVES-HOFFMAN Corp
Priority date: 1948-01-23
Filing date: 1948-01-23
Publication date: 1950-07-04
Anticipated expiration: 1967-07-04

Description

July 4,- 1950 P. R. HOFFMAN l 2,513,870

HERMETICALLY SEALED CRYSTAL Filed Jan. 23, 1948 INVENTOR /D/n//p f?. Hof/Cm cm BY I /m/ @uw y Mci A WMA/YJ Patented July 4, 1950 UNITED STATES PATENT OFFICE Application-January 23, 1948, Serial No. 3,939

Claims.

This invention relates to improvements in hermetically sealed electrical units and relates more particularly to an hermetically sealed crystal of the xed frequency type.

The various objects and advantages of the in'- vention will be apparent and best understood from the following description and the accompanying drawings in which:

Fig. l is a side view in vertical section of a container embodying the invention;

Fig. 2y is a section view taken along the line 2--f-2 of Fig. 1;

Fig. 3 is a top View of the container illustrated in Fig. 1;` and Fig. 4 is a side view in section of a closure member for the container illustrated in Fig, 1,

The importance of hermetically sealing electrical units so that the electrical .elements will be protected from changes in atmospheric conditions, such as moisture, that will aiect their electrical characteristics and proper performance is well known.` One method of constructing an hermetically sealed container is illustrated in Patent No. 2,057,790. In Such a construction the end closure pieces for the container have a resilient material such as rubber on their outer surfaces and the ends of the container are crimped or spun over so that the turned-in end of the container presses into the resilient material to form the seal. In this type of construction the entire periphery of the end of the container must be brought into engagement with the resilient material in order to form an effective seal. This makes it necessary to have special jigs or spinning tools to perform this operation and generally limits the shape of the container that may be used to a cylindrical container because of the nature of the closure operations required. In addition, such an operation must be carefully performed since even the smallest opening between the end of the container and the resilient material will destroy the effectiveness of the seal.

An hermetic seal may be obtained in accordance with the present invention with practically any shape of container and the closure may be effectively made on an ordinary press. The necessity for bringing the entire edge of the container into contact with the outer surface of the end closure is eliminated and pressure on the end closure at a few spaced points will insure a proper seal.

In a container embodying the present invention, as illustrated, there is a container Ill made of a suitable material such as brass, aluminum, or the like. The container ID illustrated is oval in shape and is closed at one end. The container is open at its other end so that a crystal I I may be placed inside of the container. The crystal II is of the fixed frequency type and isr supported by wire clips I2 and I3 that are in turn supported from the end closure I4.

The ends .of the wire clips I2 and I3 holding the crystal II contact `conductors I5 and I6 respectively that extend along opposite sides oi the crystal II. The other ends of the Wire clips I2 and I3 are soldered to eyelets or rivets I l 4and I8, respectively. The eyelets Il and IB extend through the end closure I4 and 4Serve as wiring terminals to which lead wires `I9 and 2,0- Inay ,be aiiixed.

The end closure I4 is laminated and has a rigid insulating material 2l such as a molded .synthetic resi-n, or the like' on one side `and a resilient insulating material 22 such asa synthetic rubber oi the chlorobutadiene polymer type or the like on its other side.

The open end of the container is Somewhat enlarged to accommodate the' laminated end closure. The end closure I4 is fitted into the container with the resilient material 212 resting on a lip 23 formed by a downwardly and outwardly sloping shoulder 23a. The lip 23 extends around the inside of the container and supports the end closure inside of the container. When the end closure has been placed in the container, the end of the container is crimped or pressed over the edges of the end closure to hold the end closure in the container. The turned over edges of the container engage with and press against the rigid outer surface of the end closure. This forces the resilient material 22 into contact with the entire periphery of the lip 23 and also with the inclined shoulder 23a hermetically sealing the container.

The hermetic seal obtained in this manner is not affected if the end of the vcontainer does not engage the end closure around its complete perimeter. In fact it is sufcient if the end of the container engages with the end closure I4 at a few spaced points as this will force the resilient material 22 into engagement with the lip 23 and the shoulder 23a at all points. Thus, by this arrangement an effective seal may be obtained regardless of slight irregularities or variations in the manner that the end of the container engages with the end closure.

When the end closure is secured in place, the resilient material 22 iiows along the inclined shoulders 23a as indicated at 24. This flowing of the resilient material not only forms a highly effective hermetic seal, but is also provides a gripping action that prevents breaking of the seal by shrinkage or sagging of the end closure. The eyelets 'I 'l and I8 forming the terminals for the electrical connections are also pressed into the resilient material so that they are effectively sealed against leakage of moisture or air.

l An hermetically sealed container made in accordancewith the present invention not only may be made in any shape desired, but it is also vextremely economical to manufacture as the unit may be assembled Without special jigs 0r tools.

It will be apparent that sucha container may be used for any type of electrical unit desired and it will be understood that various changes may be made in the embodiment of the invention that has been illustrated and described Without departing from the scope of the invention as defined by the appended claims.

I claim: i

l. In an hermetically sealed electrical unit the combination of a container, said container having `an opening at one end thereof, an inclined internal shoulder extending around the in- -side of the container and an end closure of insulating material fitted into said container and `being supported on a lip formed by the inclined shoulder, said end closure having a resilient material on its inner surface and a rigid material on its outer surface and the edges at the end of the container being turned .over the edge of the 4end closure to hold the closure in place and the resilient material in engagement With the 4internal lip and shoulder. Y

2. An hermetically sealed electrical unitas defined in claim 1 wherein the end closure serves as a support for an electrical element enclosed in the container and Wiring terminals extend through the end closure;

3. An hermetically sealed electrical unit as defined in claim 1 wherein the resilient material on lthe end closure is synthetic rubber like material.

4. An hermetically sealed crystal of the fixed frequency type comprising a container, said container having `an opening at one end thereof, an

4 inclined internal shoulder extending 'around the inside of the container, an end closure of insulating material fitted into the container and resting on a lip formed by said inclined shoulder, said end closure having an inner surface of resilient material engaging with said lip and an outer surface of rigid material, the edges of the end 4of the container being turned iniand engaging with the `outer vsurface of the end closure, terminals extending through the end closure and a crystal of the ixed frequency type connected to and supported from said terminals.

5. In a hermetically sealed electrical unit the combination of a container, said container having an opening at one end thereof, an internal shoulder extending around the inside of the container at its open end with `said shoulder being spaced from the end of the container, an end closure of insulating material tted into the open end of said container and resting on said shoulder, said end closure consisting of an outer member of. rigid material and an inner member of resilient material, inwardly extending portions carried by said container at ,its open end, said inwardly extending portions extending over and engaging with the rigid outer member of the end closure and urging the resilient inner member of the end closure into sealing engagement with the internal shoulder of the containerand an electrical terminal extending through said end closure, said electrical terminal having a flanged portion in sealing engagement-With the resilientinner member. of the endv closure.

PHILIP R. HOFFMAN.

REFERENCES errno The following references are of record in the file of this patent: y y

OLarte et al. Dec. 16, 1947