US3790727A - Inertia switch with resilient conductive support arm immersed in silicone base viscous fluid medium - Google Patents

Inertia switch with resilient conductive support arm immersed in silicone base viscous fluid medium Download PDF

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Publication number
US3790727A
US3790727A US00314609A US3790727DA US3790727A US 3790727 A US3790727 A US 3790727A US 00314609 A US00314609 A US 00314609A US 3790727D A US3790727D A US 3790727DA US 3790727 A US3790727 A US 3790727A
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United States
Prior art keywords
bob
switch
fluid
container
switch according
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Expired - Lifetime
Application number
US00314609A
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English (en)
Inventor
M Stand
S Glatzer
G Laserson
H Feinman
R Scappatura
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Sealectro Corp
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Sealectro Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/02—Switches operated by change of position, inclination or orientation of the switch itself in relation to gravitational field

Definitions

  • the pendulum is enclosed in a cylindrical insulator [21] Appl. No.. 314,609 containing a thick viscous fluid.
  • a metal ring is positioned adjacent to the 52 vs. C]. zoo/61.49, ZOO/61.51 bob and surrounding Under normal conditions the [51] Int. Cl.
  • INERTIA SWITCH WITH RESILIENT CONDUCTIVE SUPPORT ARM IMMERSED IN SILICONE BASE VISCOUS FLUID MEDIUM BACKGROUND OF THE INVENTION This invention relates generally to inertia or tilt switches which are not actuated or closed when at rest or when acted upon by forces of short duration. Continuous forces alternating in direction at a frequency above a predetermined rate will also fail to close the switch. The switch is closed only by a continuous force acting in a single direction for a stated time interval.
  • a pendulum type arrangement having a conductive wire suspension and a pendulum bob as one of the switch terminals.
  • a spaced ring within an enclosing hollow cylinder is the other terminal.
  • a thick viscous fluid covers the bob and the ring and slows the action of the bob to prevent contact and closure of the switch for a designed time interval after the application of a closing force.
  • Pendulum type contact switches are well known in the art but they have been used without the addition of a viscous fluid and they have responded to vibrational forces having a frequency which is too high to make the switch available as an alarm signal on a moving vehicle.
  • One of the features of the invention is the combination of a heavy pendulum bob to provide inertia and a thick fluid of high viscosity surrounding the bob to provide mechanical resistance to the switch.
  • Another feature of the invention is the ability of the switch to be operated by any low frequency force providing the force has a component which is perpendicular to the longitudinal axis of the pendulum.
  • Another feature of the invention is the ability of the switch to maintain its specified performance characteristics over a wide temperature range and at all values of air pressure.
  • the inertia switch comprises a cylindrical insulator, closed at its lower end by a conductive cup which acts as one of the switch terminals.
  • a pendulum is positioned in axial alignment with the cylinder and comprises a conductive wire, secured to the top end of the cylinder, and a metal bob at the lower end of the wire so that the bob normally is concentric with the brim of the cup.
  • a viscous fluid fills the cup.
  • FIG. 1 is a cross sectional view of the inertia switch showing the bob in its axial or normal position.
  • FIG. 2 is a cross sectional view similar to FIG. 1 but showing the bob in contact with the ring and a fluid in the cylinder.
  • FIG. 3 is a cross sectional view of the bob.
  • FIG. 4 is a top view of the inertia switch.
  • FIG. 5 is a cross sectional view, to an enlarged scale, of the switch shown in FIG. 1 and is taken along line 5-5 of that figure.
  • FIG. 6 is a cross sectional view, also to an enlarged scale, of the closed switch shown in FIG. 1 and is taken along line 6-6 of that figure.
  • the switch comprises an outer cylinder 10 made of insulator material preferably Delrin, a polyacetal resin of formaldehyde. Other insulating materials may be used provided they are good insulators and have the required mechanical strength.
  • the cylinder 10 has an integral top closure disk 11 formed with a small hole 12 in the axial position. The remainder of the cylinder 10 is hollow, having a smooth inner surface 13.
  • a suspension wire 14 is positioned in hole 12 and is sealed in position by a small amount of plastic 15. The end of wire 14 which extends above the cylinder is used as one terminal of the switch.
  • a heavy metal bob 16 is fastened to the lower end of the suspension wire 14.
  • the wire 14 is pushed into a central hole and soldered in place by a small drop of solder 17.
  • the bob is generally cylindrical but there is an annular sharp ridge or knife edge 18 formed near its lower end.
  • the bottom portion is cone shaped.
  • the knife edge 18 makes the electrical contact which closes the switch.
  • a hollow cylindrical plug 20 forms the second terminal of the switch. It is force-fitted into the lower portion of cylinder 10 and is fitted to a metal plug 21 which includes a disk 22, a tube 23, and a flanged terminal 24.
  • An inwardly extending rim 25 is formed opposite the knife edge 18, and its inner face is serrated by the formation of a plurality of saw-toothed edges. The edges make contact with the knife edge 18 on the bob 16 to make the contact.
  • the two edged portions positively cut through the film of the heavy fluid in the cylinder and assure a firm conductive contact whenever the bob is forced against the rim 25.
  • the switch is assembled by first placing the bob l6 and its suspension wire 14 in position and adding the plastic cement 15. Then the plug assembly 20, 21 is pressed into place. The switch is next turned upside down, and a viscous fluid 26 is poured into the switch through the hollow tube 23. When filled, the switch is stoppered by the addition of a cork 27 of self-setting plastic material (see FIG. 2). The switch is now ready for use, tube 23 or flange 24 serving as the second electrical terminal.
  • a sustained motion in any horizontal direction will not close the switch. It is necessary to apply a sustained force which will result in a steady acceleration or steady increase in velocity to move the bob 16 through the viscous fluid and establish electrical contact. A sustained deceleration or steady decrease in velocity will give the same results.
  • the switching action may be varied over a wide range by cnanging the composition of the fluid which surrounds the bob 16.
  • the fluid used must have certain basic characteristics such as: small temperature coefficient of viscosity; be non-corrosive; and chemically stable. Two or more fluids may be mixed to obtain the desired viscosity value, provided they are compatible and operate in a single phase over the required temperature range. Many materials are available from which to choose, such as halogenated hydrocarbons, silicones, and solutions of polymers. Three satisfactory mixtures are shown below; percentages in volume.
  • the above described switch has been found useful as a safety device in all types of moving vehicles and can be used as a signalling device on an airplane when the vehicle crashes, sending out a distress signal which can aid in locating the wrecked plane.
  • An inertia actuated electrical switch comprising; a hollow cylindrical insulative container for supporting all the switch components; a pendulum including a conductive suspension and a metal bob, the suspension secured to one end of the container and forming one of the switch terminals, the bob formed with an annular knife edge and normally in axial alignment with the cylinder; an annular contact ring also mounted in the container adjacent to the bob and having a serrated inwardly extending surface for contact by the knife edge of the bob when the switch is actuated; a quantity of viscous fluid positioned in the container and covering the pendulum bob and the contact ring; and a stoppered conductive tube being disposed within the container and connected to the contact ring for filling the container with fluid, said conductive tube forming the other tenninal of the switch.
  • a switch according to claim 1 wherein the serrated contact ring is part of a tubular insert, force-fitted into the lower portion of the container.
  • a switch according to claim 1 wherein the suspension is made of beryllium copper wire.
  • a switch according to claim 1 wherein the viscous fluid is a fluid silicone oil.
  • viscous fluid consists of three types of silicone fluid, neither of which comprises more than 50 percent of the total fluid.
  • a switch according to claim 7 wherein the viscous fluid consists of two types of silicone fluid, neither of which comprises more than 65 percent of the total fluid.
  • a switch according to claim 1 wherein the viscous fluid consists of two types of silicone fluid and bromo-fluoro-carbon oil.

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  • Switches Operated By Changes In Physical Conditions (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
US00314609A 1972-12-13 1972-12-13 Inertia switch with resilient conductive support arm immersed in silicone base viscous fluid medium Expired - Lifetime US3790727A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US31460972A 1972-12-13 1972-12-13

Publications (1)

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US3790727A true US3790727A (en) 1974-02-05

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US00314609A Expired - Lifetime US3790727A (en) 1972-12-13 1972-12-13 Inertia switch with resilient conductive support arm immersed in silicone base viscous fluid medium

Country Status (5)

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US (1) US3790727A (en:Method)
CA (1) CA977439A (en:Method)
DE (1) DE2346782A1 (en:Method)
FR (1) FR2210815B1 (en:Method)
GB (1) GB1397911A (en:Method)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3963888A (en) * 1975-02-28 1976-06-15 Riede Systems, Inc. Multi-angle tilt switch device with adjustable oscillating controller
US4910502A (en) * 1987-10-22 1990-03-20 SocieteJouan Device for detecting the unbalance of a rotating machine from a predetermined threshold
US5080362A (en) * 1990-05-01 1992-01-14 Neil Lillard Adjustable point of impact indicating device
US5842716A (en) * 1989-02-23 1998-12-01 Automotive Technologies International, Inc. Self contained side impact airbag system
US20030128475A1 (en) * 2000-10-02 2003-07-10 Wehrenberg Paul James Method and apparatus for detecting free fall
US6685218B1 (en) 1993-09-16 2004-02-03 Automotive Technologies International, Inc. Side impact sensors and airbag system
US20060017692A1 (en) * 2000-10-02 2006-01-26 Wehrenberg Paul J Methods and apparatuses for operating a portable device based on an accelerometer
USRE39868E1 (en) 1993-09-16 2007-10-09 Automotive Technologies International, Inc. Self-contained airbag system
US20100235012A1 (en) * 2009-03-13 2010-09-16 Keith Cox Automatic adjustment of thermal requirement
USRE42738E1 (en) 1997-10-28 2011-09-27 Apple Inc. Portable computers
CH707557A1 (de) * 2013-02-12 2014-08-15 Geoplan Swiss Ag Kontaktpendelvorrichtung für Baumaschinen.
US10123582B2 (en) 2013-06-26 2018-11-13 I1 Sensortech, Inc. Flexible impact sensor for use with a headpiece
CN110600322A (zh) * 2019-10-23 2019-12-20 佛山市高明欧一电子制造有限公司 一种万向倾倒开关

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2754879C3 (de) * 1977-12-09 1981-10-29 Messerschmitt-Bölkow-Blohm GmbH, 8000 München Elektrischer Schaltkontakt

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2322549A (en) * 1940-05-23 1943-06-22 Sorensen Marius Tilting switch alarm or signal
US2938973A (en) * 1957-03-27 1960-05-31 English Electric Co Ltd Mass-actuated electric switching devices
US3372386A (en) * 1964-03-13 1968-03-05 Kuratorium Fur Verkehrssicherh Apparatus for the determination of the horizontal acceleration composed of different components in automotive vehicles
US3502832A (en) * 1969-02-03 1970-03-24 Leonard H Mcroskey Force responsive switch
US3674950A (en) * 1970-10-21 1972-07-04 American Multi Lert Corp Self-aligning motion detectors

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2322549A (en) * 1940-05-23 1943-06-22 Sorensen Marius Tilting switch alarm or signal
US2938973A (en) * 1957-03-27 1960-05-31 English Electric Co Ltd Mass-actuated electric switching devices
US3372386A (en) * 1964-03-13 1968-03-05 Kuratorium Fur Verkehrssicherh Apparatus for the determination of the horizontal acceleration composed of different components in automotive vehicles
US3502832A (en) * 1969-02-03 1970-03-24 Leonard H Mcroskey Force responsive switch
US3674950A (en) * 1970-10-21 1972-07-04 American Multi Lert Corp Self-aligning motion detectors

Cited By (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3963888A (en) * 1975-02-28 1976-06-15 Riede Systems, Inc. Multi-angle tilt switch device with adjustable oscillating controller
US4910502A (en) * 1987-10-22 1990-03-20 SocieteJouan Device for detecting the unbalance of a rotating machine from a predetermined threshold
EP0313444A3 (fr) * 1987-10-22 1990-10-03 JOUAN, Société Anonyme dite Dispositif pour la détection du balourd d'une machine tournante à partir d'un seuil prédéterminé
US5842716A (en) * 1989-02-23 1998-12-01 Automotive Technologies International, Inc. Self contained side impact airbag system
US5080362A (en) * 1990-05-01 1992-01-14 Neil Lillard Adjustable point of impact indicating device
US7097201B2 (en) 1993-09-16 2006-08-29 Automotive Technologies International, Inc. Side impact sensor systems
US20070040363A1 (en) * 1993-09-16 2007-02-22 Breed David S Side Impact Sensor Systems
US7334657B2 (en) 1993-09-16 2008-02-26 Automotive Technologies International, Inc. Side impact sensor systems
US20040183287A1 (en) * 1993-09-16 2004-09-23 Breed David S. Side impact sensor systems
US6685218B1 (en) 1993-09-16 2004-02-03 Automotive Technologies International, Inc. Side impact sensors and airbag system
US20050242555A1 (en) * 1993-09-16 2005-11-03 Breed David S Side impact sensor systems
USRE39868E1 (en) 1993-09-16 2007-10-09 Automotive Technologies International, Inc. Self-contained airbag system
US7025379B2 (en) 1993-09-16 2006-04-11 Automotive Technologies International, Inc. Side impact sensor systems
US7052038B2 (en) 1993-09-16 2006-05-30 Automotive Technologies International Inc. Side impact sensor systems
US7070202B2 (en) 1993-09-16 2006-07-04 Automotive Technologies International, Inc. Side impact sensor systems
USRE44855E1 (en) 1997-10-28 2014-04-22 Apple Inc. Multi-functional cellular telephone
USRE46548E1 (en) 1997-10-28 2017-09-12 Apple Inc. Portable computers
USRE44103E1 (en) 1997-10-28 2013-03-26 Apple Inc. Portable computers
USRE42738E1 (en) 1997-10-28 2011-09-27 Apple Inc. Portable computers
USRE45559E1 (en) 1997-10-28 2015-06-09 Apple Inc. Portable computers
US7351925B2 (en) * 2000-10-02 2008-04-01 Apple Inc. Method and apparatus for detecting free fall
US20040252403A1 (en) * 2000-10-02 2004-12-16 Wehrenberg Paul James Method and apparatus for detecting free fall
US7541551B2 (en) 2000-10-02 2009-06-02 Apple Inc. Method and apparatus for detecting free fall
US7688306B2 (en) 2000-10-02 2010-03-30 Apple Inc. Methods and apparatuses for operating a portable device based on an accelerometer
US9921666B2 (en) 2000-10-02 2018-03-20 Apple Inc. Methods and apparatuses for operating a portable device based on an accelerometer
US7307228B2 (en) * 2000-10-02 2007-12-11 Apple Inc. Method and apparatus for detecting free fall
US9829999B2 (en) 2000-10-02 2017-11-28 Apple Inc. Methods and apparatuses for operating a portable device based on an accelerometer
US20060017692A1 (en) * 2000-10-02 2006-01-26 Wehrenberg Paul J Methods and apparatuses for operating a portable device based on an accelerometer
US8698744B2 (en) 2000-10-02 2014-04-15 Apple Inc. Methods and apparatuses for operating a portable device based on an accelerometer
US20080156622A1 (en) * 2000-10-02 2008-07-03 Paul James Wehrenberg Method and apparatus for detecting free fall
US20030128475A1 (en) * 2000-10-02 2003-07-10 Wehrenberg Paul James Method and apparatus for detecting free fall
US9575569B2 (en) 2000-10-02 2017-02-21 Apple Inc. Methods and apparatuses for operating a portable device based on an accelerometer
US6768066B2 (en) * 2000-10-02 2004-07-27 Apple Computer, Inc. Method and apparatus for detecting free fall
US8756176B2 (en) 2009-03-13 2014-06-17 Apple Inc. Automatic adjustment of thermal requirement based on motion detection and frequency of disturbances
US8392340B2 (en) 2009-03-13 2013-03-05 Apple Inc. Method and apparatus for detecting conditions of a peripheral device including motion, and determining/predicting temperature(S) wherein at least one temperature is weighted based on detected conditions
US20100235012A1 (en) * 2009-03-13 2010-09-16 Keith Cox Automatic adjustment of thermal requirement
CH707557A1 (de) * 2013-02-12 2014-08-15 Geoplan Swiss Ag Kontaktpendelvorrichtung für Baumaschinen.
US10123582B2 (en) 2013-06-26 2018-11-13 I1 Sensortech, Inc. Flexible impact sensor for use with a headpiece
CN110600322A (zh) * 2019-10-23 2019-12-20 佛山市高明欧一电子制造有限公司 一种万向倾倒开关
CN110600322B (zh) * 2019-10-23 2022-03-11 佛山市高明欧一电子制造有限公司 一种万向倾倒开关

Also Published As

Publication number Publication date
FR2210815A1 (en:Method) 1974-07-12
GB1397911A (en) 1975-06-18
DE2346782A1 (de) 1974-06-20
FR2210815B1 (en:Method) 1976-10-01
CA977439A (en) 1975-11-04

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