US2868922A - Vacuum switch - Google Patents

Description

R. P. LEONARD VACUUM SWITCH Jan. 13, 1959 Filed Jan. 14. 1957 2 Sheets-Sheet 1 WMW MM. 5 h 0 Z /1111!!! i\\\\\\ 3 7. i g m litm mm mmw I INVENTOR.

Jan. 13, 1959 R. P. LEONARD VACUUM SWITCH Filed Jan. 14, 1957 2 Sheets-Sheet 2 United States Patent VACUUM WITCH Redford P. Leonard, Santa Barbara, Calif., assignor to Penta Laboratories, Inc.,'SantaBarbara, Calif., a corporation of Caiifornia Application January 14, 1957, Serial No. 634,043

'8 Claims. (Cl. 200-87) Thisinvention relates to an electromagnetically actuated vacuum switch.

A principal object of this invention is to :provide an electromagnetically actuated vacuum switch having .a reciprocally mounted spring urged armature within an evacuated cylinder andwhereinthe armature is movable toan operative position and is arranged'to move to a second operative position upon application of a field of ,magnetic flux about the armature.

A feature Of this invention is thatrall .moving parts .of the switch assembly are completely contained in the evacuated housing so that there need be no translation of motion through the housing Wall.

Another feature and advantage of this invention is that in thefirst condition of operation certain contact points of the switch are forcefully spring urged into positive .mechanical and electrical union and in the second condition of operation certain other contact points are magnetically urged into positive mechanical and electrical union.

A still further feature and advantage of the invention is th'atthe arrangement and structure of movable parts allows the contact points to be joined so as to be insensitive to ambient mechanical vibrations.

Another object of the invention is to provide the switch arrangement in a housing formed to telescopically receive a solenoid which may be removably positioned around :the exterior of the housing section adjacent the armature .of the switch. Because of this feature the solenoid may .bereplaced when worn or defective. In addition the replaceable solenoid feature of the invention allows solenoids of various electrical characteristics to be used in .combinationwith the switch so as to impart greater flexibility thereto.

Another object of this invention is to provide a vacuum switch of high sensitivity, fast re-action time and grigidityiof structure sutlicient to allowthe switch to be used-under conditions of high voltage and high current.

Other objects of the present invention will become apparent upon reading the "following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

-.-Inthedrawings:

Fig. '1 is an elevational view of the housing of the preferred embodiment of the vacuum switch of the in- .vention.

Fig. :2 is a'scctional view of the embodiment of Fig. '1.

:Fig. 3 is an enlarged fragmentary view of the armature portion of the switch assembly of Figs. -1 and 2.

Fig. 4;is a sectional perspective of a modification of the invention.

.Referring now to the drawings the preferred embodimentofthe invention as illustrated in/Figs. l, 2 and 3 comprisesahousing A which is sealed to the atmosphere andevacuated. Armature assembly B is mounted within housing A to respectively open and :close contact points l2.and J13. also mounted .within the housing. .Armature I 2,868,922 Patented Jan. 13, 1959 '2 assembly B is actuated by magnetic flux from a solenoid D mounted exteriorly of the housing.

In greater detail the housing comprises a cylindrical section closed atone end by a cap 16 and opening at'the other end .to an .electrical'contact point'chamber 18. The armature assembly comprises ashaft 20 axially aligned in the center of tube '15 with a terminal portion 21 thereof projecting exteriorly ofthehousing through cap .16. .The interior portion 22 of shaft 20 terminates adjacent the opposite end of tube '15. Two cylindrical armature sections .25 and 26 areco-axially mounted on shaft 20. Cylindrical section 25 and 26 each have an inside diameter substantially smaller than the inside diameterof tube 15. Section 25 isafiixed to'shaft 20in a permanent-position by a setscrew 28. Armature section 26 is reciprocally moun-tedon shaft 2!) and positioned on the end of the shaftadjacent chamber 18.

Armature'sections '25 and 26 are both recessed as at 30 and 31 respectively to receive a helical spring 34. Helical spring-34 is thus arranged to urge the reciprocally mounted armature section 26 away from armature 25 and into chamber .18. Movement of section 26 into chamber 18 is restrained by a shaft 38 mounted within chamber 18 and arranged to carry a fixed terminal 12 of contact point 12. The bottom end '35 of armature section 26 is formed with a bracket v36 flanged outwardly to provide contact pointsupport ears 37 and 37 Movable terrninallZ of contact v:12 is arranged in alignment with terminal 12 on ear 37 The mechanical interactionef the two contacts 12* and 12 provides an electrical circuit between shaft 3.8. and armature assembly 3, and also forms a stop to limit'movement of armature section 26. A shaft 39 is provided within chamber 18 to mount a fixed terminal l3 above and aligned with terminal 13 of contact point 13 .mounted on ear37 Shafts 38 and 39 project outwardly through .the Walls of chamber 1?! to form terminal leads 40 and 41 respectively.

Reciprocally mounted armature section 26 is aligned with the respective terminals of contact points 12 and 13. This alignment ismaintained by two pins 44 affixed toarmature section 25 and slidably engaged with apertures '46 formed in the adjacent surface of armature section 26. Thus armature section 26 is restrained against relative rotational movement by pins 44.

.Solenoid D comprises a coil of wire wound to form an annulus 45 of a diameter slightly largerthan the outside diameter of tube .15.

In operation the solenoid D is-positioned over tube 15 so'that th-eccoils of the solenoid surround armature sections 25 and 26. As has been hercin'be'fore described spring 34 normally urges contact point 12 in the closed position whereat contact point 13 is open as illustrated inFig. 2. -When solenoid D is electrically energized .there is produced a field of magnetic flux within armature sections 25 and 26. The armatures are made of. soft iron orother material which is capable of rapidly being magnetized when influenced by a magnetic field but after removal of the field immediately looses the magnetic polarization. When solenoid D sets up the magnetic flux through sections 25 and 26, section 26 is magnetically forced againstsection 25 because of the magnetic attraction exerted between the two sections and by solenoid D.

When armature section 26 is magnetically urged toward section 25 contact point 13 is closed and contact point 12 is open thus breaking the circuit between terminal 40 and terminal 21 and making the circuit between terminal 41 and 21. It is obvious that upon de-energizing solenoid D that armature section .26 will return to its normal condition Whereat contact point 12 is closed and contact point 13 is open.

It ispreferable that shaft 20, pins 44 and helical spring 34 be formed ofnon-magnetic materials. The shaft pins and spring when non-magnetic not only prevents flux loss throughout the armature assembly but also prevents binding of the respective parts during energization of solenoid D. Thus with only armature sections and 26 formed of magnetizable material the maximum amount of magnetic force is available to pull armature section 26 towards the stationary section 25.

Helical spring 34 may be formed of various resilient metals. However if the switch is to be used in areas of high ambient temperature it has been found that spring 34 formed of tantalum and tungsten is particularly satisfactory because this alloy has the property of retaining temper at high temperatures.

Housing A is formed of a material sufficiently nonporous to be capable of maintaining a vacuum within the housing. The walls of tube 15 must be formed of a material which is non-magnetic so as to prevent a shielding of the flux between the solenoid D and armature assembly B. It has been found that glass or ceramic materials are suitable to form housing A.

In Fig. 4 there is provided a modification of the invention. The embodiment of Fig. 4 has a housing with an armature assembly 51 substantially identical to armature assembly B of Figs. 1, 2 and 3 except that the end 55 of the reciprocating armature section 56 is provided with a birfurcated tip 58 joined by a cross member 59. The cross member mounts a contact point 60 on the top and on the bottom of the plate. Matching con tacts 61 and 62 are provided adjacent the two contacts 60. Contact 62 is mounted on a shaft 65 below plate 59 o and contact 61 is mounted between the bifurcated tips 58 by a bracket 66. Thus in operation when a solenoid D is placed around housing 50 so as to provide a field of magnetic flux for armature assembly 51 the embodiment of Fig. 4 will operate in the same manner as hereinbefore described in connection with Figs. 1, 2 and 3. Thus during energization of the solenoid contact point 60 is engaged with contact points 61. Upon release of the magnetic field contact point 60 is engaged with contact point 62 by virtue of the force effected by spring 68 of the armature assembly.

In the embodiment of Fig. 4 the contact point chamber 69 is formed of two axially mounted dielectric cylinders 70 and 71. interposed between the two cylinders is a conductive ring 72 which is attached to bracket 59 so as to form a terminal connection 73. The bottom of chamber 69 is sealed by a concave conductive plate 75 to provide a recess for the terminal end 78 of shaft 65.

Although the foregoing invention has been described in some detail by way of illustration and example for purr poses of clarity of understanding, it is understood that certain changes and modifications may be practiced within the spirt of the invention as limited only by the scope of the appended claims.

What is claimed:

1. An electromagnetically actuated circuit breaker movable to first and second conditions of electrical conductivity within a chamber sealed to atmosphere comprising, within the chamber, a conductive member having one terminal end projecting exteriorly of said chamber, a conductive shaft having one terminal end projecting exteriorly of said chamber, a two element armature means mounted on said shaft with a first element slidably movable on said shaft to make and break electrical contact with said conductive member, said first element electrically connected to said shaft, said first element movable to a first position in electrical contact with said conductive member to render an electrical circuit between said shaft and said conductive member and to a second position out of electrical contact with said conductive member, means to normally force said first element of said armature means to one of said two positions in spaced relation to said second element, the two elements of said armature means formed of magnetizable material whereby when said armature means is subjected to magnetic flux the two elements of said armature means become magnetized and said first element is magnetically moved closer toward said second element into the other of said two positions.

2. An electric switch comprising: a housing forming a chamber sealed to the atmosphere; a shaft having a portion thereof within the chamber; an armature assembly mounted on said shaft within said chamber; said armature assembly having a fixed section, a movable section reciprocally movable on said shaft toward and away from the fixed section, and spring means to urge the movable section away from the fixed section; electrical contacts mounted within said chamber movable to first and second conditions of electrical conductivity; electrical leads extending exteriorly of the housing and connected to the respective said electrical contacts; said shaft and movable section comprising one of said leads; fixed means within said chamber to restrain movement of said movable section at a predetermined distance from said fixed section whereat said movable section is positioned to cause said contacts to be in the first condition of electrical conductivity, said fixed and movable sections formed of highly magnetizable metal; and electromagnetic flux generating means disposed exteriorly of said chamber and arranged to create magnetic flux about said armature assembly to magnetize said sections and magnetically cause said movable section to move toward said fixed section whereat said movable section is positioned to cause said contacts to be in the second condition of electrical conductivity.

3. An electric switch comprising: a housing having a chamber sealed to the atmosphere; a shaft having a portion thereof within the chamber; an armature assembly mounted within said chamber on said shaft; said armature assembly having a fixed section rigidly connected to said shaft, a movable section slidably mounted on said shaft and movable toward and away from the fixed section, and spring means to urge the movable section away from the fixed section; fixed contact means Within said chamber to restrain movement of said movable section at a predetermined distance from said fixed section whereat the fixed means is in electrical contact with the movable section; said fixed and movable sections formed of highly magnetizable metal; electromagnetical flux generating means disposed exteriorly of said chamber and arranged to create magnetic flux about said armature assembly to magnetize said sections and magnetically cause said movable section to move toward said fixed section to open the electrical contact between said fixed contact means and said movable armature section; and electrical leads extending exteriorly of the housing and connected to the fixed contact means and the movable section respectively said shaft being formed of a highly conductive material and electrically connected to said first and second armatures to provide a high conductivity path between said armatures.

4. An electric switch comprising: a housing forming a chamber sealed to the atmosphere; an armature assembly mounted within said chamber; said armature assembly having a shaft having a first portion mounted exteriorly of said housing and a second portion mounted within said chamber; a first armature means mounted in a fixed position on the second portion of said shaft; a movable armature means reciprocally mounted on said second portion of said shaft and movable toward and away from the fixed armature means; and spring means to urge the movable armature means away from the fixed armature; fixed electrical contact means within said chamber positioned to restrain movement of said movable armature means at a predetermined distance from said fixed armature means whereat the fixed contact means is in electrical contact with the movable armature means; said fixed and movable armature means formed of high magnetizable metal; electromagnetic flux generating means disposed exteriorly of said chamber and arranged to create 5 magnetic flux about said armature assembly to magnetize said armature means to magnetically cause said movable armature means to move toward said fixed armature means to open the electrical contact between fixed contact means and said movable armature means; and said movable armature means electrically connected to said shaft; and an electrical lead extending exteriorly of the housing connected to said fixed contact means; said shaft being formed of a highly conductive material and electrically connected to said first and second armatures to provide a high conductivity path between said armatures.

5. An electric switch according to claim 3 and wherein said armature assembly is provided with means to restrain relative rotational movement of said movable armature means with respect to said fixed armature means.

6. An electric switch according to claim 3 and wherein said movable armature means is provided with an electrical contact and said armature assembly is provided with means to restrain relative rotational movement of said movable armature means with respect to said fixed armature means in a position to align said armature contact point with said fixed contact means.

7. An electric switch according to claim 3 and wherein 6 said shaft and said spring means are formed of nonmagnetic material.

8. An electric switch according to claim 3 and wherein said armature assembly is provided with pin means fixed to one said armature means and slidably engaged with the other armature means to restrain relative rotational movement of said movable armature means with respect to said fixed armature means with said pin means, said shaft, and said spring means being formed of non-magnetic material.

References Cited in the file of this patent UNITED STATES PATENTS 946,215 Geissinger Jan. 11, 1910 1,175,323 Wikander Mar. 14, 1 916 2,001,579 Leece et al. May 14, 1935 2,029,267 Leece et a1 Jan. 28, 1936 2,131,942 Evans et al Oct. 4, 1938 2,156,974 Doan May 2, 1939 2,170,961 Borgkvist Aug. 29, 1939 2,360,941 Eitel et a1 Oct. 24, 1944 2,485,024 Vale et al Oct. 18, 1949

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