US3116384A - Method of conditioning and all-position mercury switch - Google Patents

Method of conditioning and all-position mercury switch Download PDF

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Publication number
US3116384A
US3116384A US149691A US14969161A US3116384A US 3116384 A US3116384 A US 3116384A US 149691 A US149691 A US 149691A US 14969161 A US14969161 A US 14969161A US 3116384 A US3116384 A US 3116384A
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US
United States
Prior art keywords
mercury
switch
reservoir
contacts
swinger
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US149691A
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English (en)
Inventor
William D O'brien
Jr Charles E Pollard
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to BE624066D priority Critical patent/BE624066A/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US149691A priority patent/US3116384A/en
Priority to DE19621690789 priority patent/DE1690789B1/de
Priority to GB40363/62A priority patent/GB1015582A/en
Priority to FR914132A priority patent/FR1337721A/fr
Application granted granted Critical
Publication of US3116384A publication Critical patent/US3116384A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/06—Contacts characterised by the shape or structure of the contact-making surface, e.g. grooved
    • H01H1/08—Contacts characterised by the shape or structure of the contact-making surface, e.g. grooved wetted with mercury
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
    • H01H11/005—Apparatus or processes specially adapted for the manufacture of electric switches of reed switches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H51/00—Electromagnetic relays
    • H01H51/28—Relays having both armature and contacts within a sealed casing outside which the operating coil is located, e.g. contact carried by a magnetic leaf spring or reed

Definitions

  • Mercury switches in general, have enough mercury in them to make the attitude of the switch housing significant; for example, in the tilting type switch, the attitude determines whether the switch is on or oil.
  • the switch In the sealed reed, mercury-wetted-contact type, as disclosed in Patent 2,868,926 to C. E. Pollard, In, issued January 13, 1959, the switch must be used in a vertical, or nearly vertical, position so that the free mercury will not cause a short circuit by flowing between the contacts.
  • the present invention involves a sealed, mercurywetted-contact reed switch with no excess mercury to ilow around, whereby it may be used in any attitude or position.
  • mercury in the usual mercury, reed type switch, as disclosed in the noted Pollard patent, there is mercury in the reservoir or cup and also on the contacts and on the swinger which projects from the cup.
  • the swinger is usually provided with a plurality of longitudinal grooves to aid in conduct ing mercury from the cup to the contacts and for present ing a greater storage surface than a smooth swinger.
  • Applicants have solved the problem of making a sealed reed switch with mercury-wetted contacts and operable in any position by having in the switch envelope or housing only sufficient mercury to wet the swinger and the contacts.
  • Such a switch might be made by sealing within the envelope 1016 than enough mercury to wet the switch ports, activating the switch, and thereafter unsealing the envelope, removing the excess mercury, and then rescaling the envelope.
  • the operation called activating comprises the assembly and agitating it to suitably coat the contacts and the swinger with mercury. This way or making a switch appears to be simple, but carrying it out properly is the first concern of the present invention.
  • a switch in accordance with this invention proerly made, may be good for about one million operatic. s, but this would be drastically reduced if too much mercury were removed. Moreover, once the right amount has been determined, the question of reproducibility arises; that is, will each switch be the same as every other switch? There also arises the question or contamination during mercury removal.
  • One of the usual ways of making a mercury switch is to introduce mercury into the envelope in which the reeds are mounted, to evacuate and fill the envelope with a suitable gas, say hydrogen, and then to seal the envelope. it has been iound, as set forth in Patent 2,732,459
  • An object then of this invention is to take advantage of some of the properties of sealed reed, mercury switches, namely, mercury wetting of contacts, and, at the same time, eliminate one of its undesirable characteristics, namely, limited position of use.
  • an object is to make a sealed reed switch having mercury-wetted contacts but which is usable in any attitude, namely, an all-position switch.
  • One of the features of this invention resides in the means for and method of making a sealed reed mercury switch having therein only sutlicient mercury to properly wet tie contacts and the contact swinger.
  • FIG. 1 shows a longitudinal section of a switch in accordance with this invention
  • FIG. 2 shows the switch of FIG. used during its manufacture
  • FIG. 3 shows diagrammatically a centrifuge for performing one of the process steps on the FIG. 2 assembly.
  • the switch comprises a housing ltl which may be a section of glass tubing.
  • a pair of fixed contacts ll and 12 are secured in spaced relation by means of the terminals l3 and 14, respectively. These terminals are sealed through one end of the housing it
  • a movable contact carrier or swinger 15 projects between the fixed contacts and 12 and may be biased 1 with attachments llEL either of them or neither, as required, by the way the swinger is initi ly fixed in the housing.
  • the swinger is attached to a tab 16 which, in turn, is secured to and projects from the tubulation 1').
  • the tabulation i7 is, as is well known, in communication with the interior of the housing.
  • the tube or tubulation It? may be made or" a suitable metal or alloy, such as nickel-iron. his tube is flared at its inner end, and its lip and the glass of the housing are aired so that there is no pocket to interfere with egress of mercury.
  • the tube 1? is sealed at It will be noted, however, by reference to FIG. 2 that the making of the switch the tribulation 17 e ads to and is sealed into an auxiliary housing 21 which may also be of glass.
  • the auxiliary housing also ha tribulation at its outer end.
  • he switches are made up with their attachments, as in FIG. 2.
  • Email bits or slugs of copper, and of tin, if used, are introduced into the housing.
  • a quantity of mercury greater than that need for the finished switch is then added.
  • the assembly is then evacuated and filled with a suitable gas, such as hydrogen, by way of the tube 22, the housing 21, and the tube 17.
  • the tube is then closed as by welding at 23 (see FIG. 3).
  • the next step is to activate the switch which, viously noted, comprises the application of heat agitation of tie housing.
  • a suitable temperature is 320 degrees Centigrade.
  • the activation may he a vibration of small amplitude, for example, 32 of an inch, at about 60 vibrations per second in a longitudinal direction.
  • the switch is held in a vertical position with the contacts down, and the mercury in which the free end of the swinger and the fixed contacts are immersed travels up the swinger to coat it completely.
  • This small amplitude vibration avoids splashing of mercury with its attendant difiiculties.
  • One result of splashing might be to Wet the inside of the connecting tube with the mercury-tin-copper solution.
  • the tin and copper which could not be easil removed later, would interfere with later welding of the tube to seal the switch.
  • the manufacturing assembly is clamped in a centrifuge, as in H6. 3, for the removal of excess mercury.
  • the centrifuge may be a tube secured to a rotatable shaft 31 and having a pin, screw, or other means for retaining the switch during rotation.
  • the screws 32 may be used. It has been found that rotation for about 30 seconds at a speed corresponding to a centrifugal acceleration about 30 times that of gravity serves the purpose. For noted switch, about 750 revolutions per minute is suitable, with the switch contacts at about two inches from the center of rotation. This speed and radius amounts to an acceleration of about 32.5 gs; up to about 35 gs appears to be reasonable. In other words, the range is about 36 to 35 gs for satisfactory manufacture.
  • the tubulation 17 is sealed at an intermediate point, as indicated by the arrow 25 in FIG. 2. This is the seal 18 shown in FIG. 1.
  • the sealing may be, and advantageously is, by welding. In order to be sure that there is no condensed mercury vapor in the tube 17 at the sealing zone, heat is applied to the tube before welding to evaporate this mercury; otherwise, the weld might not be good.
  • the switch made in accordance with this invention appears to be capable of about one million operations before the mercury wetting becomes ineffective.
  • the mercury that is on the contacts and the swinger will remain there unless subjected to an acceleration greater than the 30 to 35 gs used during its manufacture.
  • the method of conditioning an all-position sealed reed, mercury switch by storing mercury on the contacts and the swinger only comprises including a reservoir in the tribulation that normally extends from the switch envelope during manufacture, injecting into the envelope an excess of mercury, evacuating and sealing the tubulation at a point to include the reservoir, activatas preto and the ing the switch by agitating and heating it to cause mercury to adhere to the contacts and the swinger, transferring the remaining mercury to the reservoir by centrifuging at a speed to attain a radial acceleration 30 to 35 times the acceleration of gravity, sealing the tu'oulation between the envelope and the reservoir, and severing the tabulation to remove the reservoir.
  • the method of conditioning all-position sealed reed, mercury switch by storing mercury on the contacts and the swinger only that comprises including a reservoir in the tribulation that normally extends from the switch envelope during manufacture, injecting into the switch envelope an excess of mercury, evacuating and sealing the tabulation at a point to include the reservoir, activating the switch by agitating and heating it to cause mercury to adhere to the contacts and the swinger, transing the remaining mercury to the reservoir by centrnuging at a speed to attain a radial acceleration 32.5 times the acceleration of gravity, sealing the tribulation ,veen the envelope and the reservoir, and severing the tLlOtllZliiOfl to remove the reservoir.
  • the method of conditioning an all-position sealed reed, mercury switch by storing mercury on the centre the sger only comprises including a reservoir in the tribulation that normally extends from the switch envelope during manufacture, injecting into the envelope by way of the reservoir an excess of mercury, evacuating and sealing the tribulation at a point to include the reservoir, activating the switch to cause mercury to adhere to the contacts and the swinger, transferring the remaining mercury to the reservoir by centrifuging at a speed to attain a radial acceleration 30 to 35 times the acceleration of gravity, sealing the tabulation between the envelope and the reservoir, and severing the tubulation to remove the reservoir.
  • the method of conditioning an all-position sealed reed, mercury switch that includes an envelope, fixed contacts, a contact swinger, and a tubulation, by storing mercury on the contacts and the swinger only, that comises temporarily including a reservoir in the tubulation, injecting into the envelope an excess of mercury, evacuating and sealing the tubulation at a point to include the reservoir, activating the switch by agitating the heating it to cause mercury to adhere to the contacts and the swinger, transferring the remaining mercury to the reservoir by centrifuging at a speed to attain a radial acceleration 30 to 35 times the acceleration of gravity, sealing the tabulation between the envelope and the reservoir, and severing the tabulation to remove the reservoir.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Manufacture Of Switches (AREA)
  • Contacts (AREA)
US149691A 1961-11-02 1961-11-02 Method of conditioning and all-position mercury switch Expired - Lifetime US3116384A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE624066D BE624066A (en(2012)) 1961-11-02
US149691A US3116384A (en) 1961-11-02 1961-11-02 Method of conditioning and all-position mercury switch
DE19621690789 DE1690789B1 (de) 1961-11-02 1962-10-20 Lageunabhaengiger Quecksilberzungenschalter und Verfahren zu seiner Herstellung
GB40363/62A GB1015582A (en) 1961-11-02 1962-10-25 Improvements in or relating to sealed magnetic reed contact devices
FR914132A FR1337721A (fr) 1961-11-02 1962-10-31 Interrupteur à mercure fonctionnant dans toutes les positions

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US149691A US3116384A (en) 1961-11-02 1961-11-02 Method of conditioning and all-position mercury switch

Publications (1)

Publication Number Publication Date
US3116384A true US3116384A (en) 1963-12-31

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Family Applications (1)

Application Number Title Priority Date Filing Date
US149691A Expired - Lifetime US3116384A (en) 1961-11-02 1961-11-02 Method of conditioning and all-position mercury switch

Country Status (4)

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US (1) US3116384A (en(2012))
BE (1) BE624066A (en(2012))
DE (1) DE1690789B1 (en(2012))
GB (1) GB1015582A (en(2012))

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11309140B2 (en) * 2019-01-04 2022-04-19 Littelfuse, Inc. Contact switch coating

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3269978D1 (en) * 1981-07-24 1986-04-24 Standex Electronics Uk Ltd Mercury containing reed switches

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2445406A (en) * 1944-07-21 1948-07-20 Bell Telephone Labor Inc Circuit maker and breaker
US2769875A (en) * 1953-09-25 1956-11-06 Bell Telephone Labor Inc Mercury contact switch

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL190202B (nl) * 1953-09-21 Nicholson Terence Peter Cilinderkoppakking voor een verbrandingsmotor.
US2911500A (en) * 1955-02-18 1959-11-03 Bell Telephone Labor Inc Mercury switches
US2868926A (en) * 1957-06-25 1959-01-13 Bell Telephone Labor Inc Switch

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2445406A (en) * 1944-07-21 1948-07-20 Bell Telephone Labor Inc Circuit maker and breaker
US2769875A (en) * 1953-09-25 1956-11-06 Bell Telephone Labor Inc Mercury contact switch

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11309140B2 (en) * 2019-01-04 2022-04-19 Littelfuse, Inc. Contact switch coating
US20220122784A1 (en) * 2019-01-04 2022-04-21 Littelfuse, Inc. Contact switch coating

Also Published As

Publication number Publication date
BE624066A (en(2012))
GB1015582A (en) 1966-01-05
DE1690789B1 (de) 1970-03-19

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