US3769472A - Inertia sensor switch - Google Patents

Inertia sensor switch Download PDF

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Publication number
US3769472A
US3769472A US00283241A US3769472DA US3769472A US 3769472 A US3769472 A US 3769472A US 00283241 A US00283241 A US 00283241A US 3769472D A US3769472D A US 3769472DA US 3769472 A US3769472 A US 3769472A
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United States
Prior art keywords
opening
mass
switch
chamber
inertia
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Expired - Lifetime
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US00283241A
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English (en)
Inventor
L Bell
W Gruber
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TRW Technar Inc
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TRW Technar Inc
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Publication date
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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
    • H01H35/027—Switches operated by change of position, inclination or orientation of the switch itself in relation to gravitational field the inertia mass activating the switch mechanically, e.g. through a lever

Definitions

  • This invention relates to an inertia switch which embodies a mass movably mounted between inclined structure and, when at rest, on a fixed ring or other means providing an aperture for contact to spring extension means.
  • the spring extension means applies a force on the mass with certain positive benefits to be discussed in detail hereinafter. In other positions, the mass is displaced from the aperture means as a result of certain G forces on the switch. The mass then is no longer in contact with the spring extension. In these positions, the electrical contact to which the spring extension is affixed is not in contact with its associated terminal and certain functions are rendered inoperative.
  • the electrical contact which the mass presses into a contact position when the mass is at rest on the aperture means exerts .upward (against the force of gravity) force on the mass through the spring extension so that the mass is much more sensitive to G level force than otherwise.
  • the mass when the mass has been removed from its position at rest as a result of G forces on the sensor and seeks to return-to its rest position, it must act against the force of the spring extension acting against it.
  • the sensitivity of inertia switch is maximized and controlled, while still enabling a substantial and stable mass to be employed.
  • FIG. 1 shows one embodiment of the sensor with a spherical mass in rest position.
  • FIG. 2 shows a detailed embodiment of the invention with the spherical mass moved from its rest position and out of contact with the spring extension.
  • FIG. 3 shows a graph illustrating advantages of the invention.
  • FIG. 4 shows the sensor of FIG. 1 with an inertia mass of preferred configuration in the rest position.
  • FIGS. 5 and 6 show other embodiments of the sensor.
  • an inertia sensor 1 with cylindrical side walls 2 and a top 3 and bottom affixed thereto define a chamber 50.
  • a ring 5 which forms an aperture adjacent the bottom 20 and preferably on the central vertical axis A-A of the sensor.
  • the bottom 20 is provided with a hole 21 immediately below and contiguous with the aperture 7.
  • a mass 4 is movably contained Within the aperture and normally rests in said aperture.
  • the inertia mass 4 in this embodiment is in the form of I a ball.
  • the ring 4 may be dispensed with, as shown in Attached to the bottom 20 of the sensor is a base 6 .upon which the sensor normally stands in an attitude parallel with the horizontal.
  • the base 6 and bottom 20 define an interior pocket which connects with the hole 21.
  • Extending into the pocket 70 at one end thereof is a terminal contact 9 and extending from the pocket preferably on the opposite end thereof is a sec-' ond terminal contact 10.
  • a leaf spring 1 l which makes electrical contact from the terminal 9 to the terminal 10, directly extends across the pocket to make such contact. Contact is made by terminal contact point 12 on the leaf spring 11 touching the terminal 10.
  • the leaf spring is pressed or otherwise in engagement with the terminal 9.
  • the ball 4 when resting in the aperture, pushes down on the extension 13 to force contact at 12 of the spring 11 with the terminal 10. Simultaneously, because of a pre-set bias of the leaf spring 11 to move in a direction toward the chamber 50, the spring extension 13 exerts a force on the ball in an upward direction, causing the ball to be more sensitive to G forces than otherwise.
  • the extension 13 exerts a force on the ball in opposition to the force of gravity when the switch is in its normally deployed position, if the inertia switch 1 is inverted as a result of, say, a rollover when used in an automotive vehicle, the disengagement of the mass from the spring extension will occur as soon as the mass moves away from the spring extension and befor total inversion, as a result of the free-fall condition caused by the rapidly occurring inversion, causing opening of the contact between the spring at 12 and the terminal 10. In the case of automotive useage, as will be discussed hereinafter, such opening of the contact could result in locking of seat belt retractor.
  • the switch contact 12 is not in contact with the terminal 10 and thus is open.
  • the ball 4 must move out of and a certain distance from its position of rest in the aperture before contact with the spring extension is lost, and this necessity for the G forces moving the ball to be sufficient to disengage the ball from the aperture and then move it such certain distance results in a filtering out of those G forces or pulsations which should not activate the sensing device (such as in the case of the effect of rough road shocksin automotive useage).
  • the mass 4 is shown as a cylindrical device 14 with a cone 15 at the top thereof and a section 16 at'the bottom thereof, shown'as located within the ring and in contact with the spring extension.
  • the conical top has the advantage that, in one embodiment, when the mass is tipped and the top 3 is sufficiently low, the section 16 cannot fully disengage from the aperture 7 and contact with the spring extension may not therefore be lost.
  • the top 3 is located close enough to the ring 5, or other aperture forming means, so that the mass 4, in its rest position, when the inertia device is standing on its base 6 and not undergoing sufficient G forces, will have to rest in the aperture.
  • the leaf extension is disposed with, and the leaf spring 11 is so positioned and biased so as to be in direct contact with I mass, the ball in this figure, when the mass is in the rest position in the aperture.
  • the spring 11 in this embodiment functions to exert force on the mass in the rest position.
  • G level forces are plotted against the angle of displacement of the mass 4 of FIG. 4 from its position of rest.
  • the G level necessary to keep the mass displaced lessens as the angle of displacement'is increased, .the same spring force on the mass was utilized in each case (the spring force here being one-half of the weight of the mass).
  • the G level force decreases more rapidly as the angle of displacementincreases, as shown beginning at A in FIG. 3, because the leaf spring 11 is no longer in contact with the terminal l0 and thus no longer is supporting the mass in contact with the extension 13.
  • the leaf extension 11 has risen from its position of terminal contact at 12 to a position where the terminal contact 12 has moved to the underside of the bottom 20 and no further substantial movement of the leaf spring or its extension is possible. Since the mass then is no longer supported by the spring extension, greater G level forces are necessary to increase the angle of displacement of the mass. Such displacement is shown by the portion B of the graph. Without the influence of the leaf spring on the mass, a plotting back on the graph to the initial G level forces required to initiate displacement of the mass, as shown by the dotted lines D on the graph, show the substantially higher initial force.
  • a contact terminal 17 may be placed adjacent to the terminal arm I0 and thereabove, said terminal arm 10 making contact with the leaf spring 11 at 12 when the mass has moved fully away from the leaf spring and its extension and substantial further movement of the leaf spring upward under its bias is impossible.
  • Said terminal 17 leads, for example, to a signal which is electrically energized to show the G level condition or the failure of contact of the leaf spring 11 with terminal 17 (which might be the switchs own failure).
  • An inertia switch comprising achamber formed by top, side walls and base having an opening therein, a freely movable mass contained within said chamber and larger in diameter than said opening so as to be removably positioned as a result of inertial force in said opening under rest conditions, said chamber having inclined means for returning said mass to said position in said opening, biased means underlying said opening and mounted on said base for contacting and applying a predetermined force to a portion of said mass extending through said opening when in said opening, said mass moving from its rest position only on overcoming the combination of force thereon as a result of gravity, the incline and said bias, said biased means moving as a result of said contact in a direction against its bias, and switch means operatively associated with said biased means for contact therewith on movement in said direction.
  • said biased means consisting of a spring extending from said switch means and extending into said opening.

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  • Switches Operated By Changes In Physical Conditions (AREA)
  • Special Spraying Apparatus (AREA)
  • Catching Or Destruction (AREA)
US00283241A 1972-08-23 1972-08-23 Inertia sensor switch Expired - Lifetime US3769472A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US28324172A 1972-08-23 1972-08-23

Publications (1)

Publication Number Publication Date
US3769472A true US3769472A (en) 1973-10-30

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ID=23085159

Family Applications (1)

Application Number Title Priority Date Filing Date
US00283241A Expired - Lifetime US3769472A (en) 1972-08-23 1972-08-23 Inertia sensor switch

Country Status (7)

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US (1) US3769472A (en(2012))
JP (1) JPS4985575A (en(2012))
CA (1) CA999664A (en(2012))
DE (1) DE2341862A1 (en(2012))
FR (1) FR2197221B1 (en(2012))
GB (1) GB1424056A (en(2012))
IT (1) IT994638B (en(2012))

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4022998A (en) * 1972-06-13 1977-05-10 Foehl Artur Acceleration and retardation responsive electric control device
US4071723A (en) * 1975-05-13 1978-01-31 Inertia Switch Limited Plunger-release shock responsive control apparatus having adjustable seat for sensor mass
US4097698A (en) * 1975-03-12 1978-06-27 Inertia Switch Limited Seismonastic switches with inertia responsive controller
US4185651A (en) * 1977-06-30 1980-01-29 Paulson Eugene K Inertially triggered fluid flow control device
US4775854A (en) * 1986-01-31 1988-10-04 Cottrell Samuel F H Swimming pool alarm
US5155308A (en) * 1991-06-24 1992-10-13 Honeywell Inc. Inclination sensitive switch
US5276424A (en) * 1992-04-20 1994-01-04 Hegemann John J Attention getting sign
US6518523B1 (en) * 2001-11-13 2003-02-11 Tien-Ming Chou Tilt switch
US7473858B1 (en) * 2006-12-01 2009-01-06 Mercury Displacement Industries, Inc. Movement detecting device
CN101800532A (zh) * 2010-02-26 2010-08-11 中北大学 微型开关
US20130001053A1 (en) * 2011-06-30 2013-01-03 Xiao-Feng Li Tilt switch

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2412807C3 (de) * 1974-03-16 1981-12-03 Albert 7972 Isny Steinmeier Beschleunigungsgrenzwertschalter
JPS5250579A (en) * 1975-10-20 1977-04-22 Shigekuma Tsukamoto Vibration switch
US4066858A (en) * 1975-11-17 1978-01-03 International Telephone And Telegraph Corporation Vertical float switch
JPS5289654U (en(2012)) * 1975-12-26 1977-07-05

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1044228A (en) * 1907-12-11 1912-11-12 Newell & Neal Safety-chest.
US1662979A (en) * 1927-05-07 1928-03-20 Paul R Nelson Circuit closer
US3457382A (en) * 1967-06-20 1969-07-22 Susquehanna Corp Omnidirectional impact switch
US3466045A (en) * 1966-03-21 1969-09-09 Fredric B Walton Random selector system for advertising,sales promotion,and selection of award recipients
US3484571A (en) * 1968-03-15 1969-12-16 Us Navy Inertia switch
US3644921A (en) * 1969-12-30 1972-02-22 Cat Products Inc Alarm with trundle switch
US3723680A (en) * 1970-08-21 1973-03-27 Tokai Rika Co Ltd Acceleration responsive switching device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4221431Y1 (en(2012)) * 1965-02-15 1967-12-09
FR1504706A (fr) * 1966-10-24 1967-12-08 Cervas Dispositif de commande de contacts électriques

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1044228A (en) * 1907-12-11 1912-11-12 Newell & Neal Safety-chest.
US1662979A (en) * 1927-05-07 1928-03-20 Paul R Nelson Circuit closer
US3466045A (en) * 1966-03-21 1969-09-09 Fredric B Walton Random selector system for advertising,sales promotion,and selection of award recipients
US3457382A (en) * 1967-06-20 1969-07-22 Susquehanna Corp Omnidirectional impact switch
US3484571A (en) * 1968-03-15 1969-12-16 Us Navy Inertia switch
US3644921A (en) * 1969-12-30 1972-02-22 Cat Products Inc Alarm with trundle switch
US3723680A (en) * 1970-08-21 1973-03-27 Tokai Rika Co Ltd Acceleration responsive switching device

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4022998A (en) * 1972-06-13 1977-05-10 Foehl Artur Acceleration and retardation responsive electric control device
US4097698A (en) * 1975-03-12 1978-06-27 Inertia Switch Limited Seismonastic switches with inertia responsive controller
US4071723A (en) * 1975-05-13 1978-01-31 Inertia Switch Limited Plunger-release shock responsive control apparatus having adjustable seat for sensor mass
US4185651A (en) * 1977-06-30 1980-01-29 Paulson Eugene K Inertially triggered fluid flow control device
US4775854A (en) * 1986-01-31 1988-10-04 Cottrell Samuel F H Swimming pool alarm
US5155308A (en) * 1991-06-24 1992-10-13 Honeywell Inc. Inclination sensitive switch
US5276424A (en) * 1992-04-20 1994-01-04 Hegemann John J Attention getting sign
US6518523B1 (en) * 2001-11-13 2003-02-11 Tien-Ming Chou Tilt switch
US7473858B1 (en) * 2006-12-01 2009-01-06 Mercury Displacement Industries, Inc. Movement detecting device
CN101800532A (zh) * 2010-02-26 2010-08-11 中北大学 微型开关
US20130001053A1 (en) * 2011-06-30 2013-01-03 Xiao-Feng Li Tilt switch

Also Published As

Publication number Publication date
DE2341862A1 (de) 1974-02-28
CA999664A (en) 1976-11-09
GB1424056A (en) 1976-02-04
FR2197221A1 (en(2012)) 1974-03-22
JPS4985575A (en(2012)) 1974-08-16
IT994638B (it) 1975-10-20
FR2197221B1 (en(2012)) 1977-02-25

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