WO1996002927A1 - Sensor with laterally-supported beam contacts - Google Patents
Sensor with laterally-supported beam contacts Download PDFInfo
- Publication number
- WO1996002927A1 WO1996002927A1 PCT/US1995/009034 US9509034W WO9602927A1 WO 1996002927 A1 WO1996002927 A1 WO 1996002927A1 US 9509034 W US9509034 W US 9509034W WO 9602927 A1 WO9602927 A1 WO 9602927A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- housing
- arms
- contact
- beam contact
- passage
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
- H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
- H01H1/24—Contacts characterised by the manner in which co-operating contacts engage by abutting with resilient mounting
- H01H1/26—Contacts characterised by the manner in which co-operating contacts engage by abutting with resilient mounting with spring blade support
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H35/00—Switches operated by change of a physical condition
- H01H35/14—Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch
Definitions
- the invention broadly relates to electromechanical transducers which employ beam contacts to close an electrical circuit in response to a mechanical input. More specifically, the invention relates to acceleration sensors employing an inertial "sensing" mass which moves in response to acceleration from a first position within a passage to a second position therein, whereupon the sensing mass physically bridges a pair of beam contacts cantilevered into the passage.
- Known cantilevered-beam contacts for use in acceleration sensors are typically stamped from a flat strip of metal and are nominally rectangular in cross-section.
- One end of each beam contact is securely mounted to an insulated portion of the accelerometer housing and otherwise electrically connected with an electrical lead extending from the housing.
- the other end or “free end” of each beam contact projects into the passage in order that it might make contact with an electrically- conductive surface on the sensing mass when the latter moves to the second position within the passage, whereby a circuit is closed to indicate such sensing mass movement.
- Such known beam contacts are generally limited as to the amount of elastic travel that can be achieved at their free ends for a given package size, since each contact experiences elastic strain only along that portion of its length which actually projects into/across the passage. Moreover, such known beam contacts exhibit a tendency to take on a permanent set, i.e., experience plastic strain, when deflected by the sensing mass in the event of a substantial acceleration input to the accelerometer housing.
- Another common problem inherent to such known beam contacts is failure through the mechanism of fatigue, particularly where the sensor is used as a "safing" sensor, with its relatively lower threshold and correlatively frequent contact closure.
- Another object of the invention is to provide an acceleration sensor which features an increased resistance to fatigue than is typical of known cantilevered beam contacts.
- An improved acceleration sensor includes a housing having an internal passage defined therein about a first axis, a sensing mass located within the passage which moves in response to acceleration from a first position within the passage to a second position therein, and a pair of electrical contacts projecting into the passage so as to be bridged by a conductive surface on the sensing mass when the sensing mass reaches its second position within the passage, thereby closing an electrical circuit.
- each of the contacts comprises a cantilevered beam, the supported end of which includes diametrical, outwardly-extending arms which are themselves secured to the housing only at their out-board ends. The outwardly-extending arms flex in torsion when the mass otherwise deflects the free end of the cantilevered beam upon contact therewith, thereby providing greater elastic travel of the beam's free end, enhanced reliability, and an attendant increase in contact dwell.
- FIG. 1 is a longitudinal view in cross-section of an improved acceleration sensor constructed in accordance with the invention.
- FIG. 2 is a side elevational view, partially in crosssection, of the improved acceleration sensor shown in FIG. 1 along line 2-2 thereof.
- the invention broadly relates to electromechanical transducers which employ beam contacts to close an electrical circuit in response to a mechanical input.
- electromechanical transducers which employ beam contacts to close an electrical circuit in response to a mechanical input.
- an accelerometer such as might be used to trigger deployment of a vehicle safety restraint in the event of a crash or marked vehicle deceleration.
- an improved acceleration sensor 10 constructed in accordance with the invention includes a housing 12 having a cylindrical passage 14 formed therein about a first axis 16.
- An inertial sensing mass 18 located within the passage 14 is nominally biased to a first or "rest" position within the passage 14 by suitable biasing means known to one of ordinary skill in the art, illustrated schematically in FIG. 1 by a spring 20.
- the sensing mass 18 is movable within the passage 14 along the first axis 16 from its first position to a second position therein in response to application of an acceleration input to the housing 12 along the first axis 16.
- the acceleration sensor 10 further comprises a pair of elongate electrically- conductive contacts 22, or "beam contacts 22", a cantilevered portion 24 of each of which projects into the passage 14 so as to be bridged by an electrically-conductive surface 26 on the sensing mass 18 when the sensing mass 18 moves to its second position within the passage 14.
- each beam contact 22 has a supported end 28 secured to the housing 12 proximate to the passage 14 therein and a cantilevered free end 30 projecting into the passage 14 such that the electrically- conductive surface 26 on the sensing mass 18 makes contact with the cantilevered free end 30 of each beam contact 22 when the sensing mass moves to its second position in the passage 14.
- each beam contact 22 is stamped from a thin sheet of a suitable material, such as a sheet of beryllium-copper, perhaps 0.075 mm thick.
- the supported end 28 of each of the beam contacts 22 includes a pair of lateral arms 32 which extend outwardly in diametrically-opposite directions, each preferably being substantially perpendicular to the direction in which the beam contact's cantilevered free end 30 extends.
- each of the arms 32 is secured to the housing 12 as by a threaded fastener 34 only at the outboard end 36 thereof, with the supported end 28 of each beam contact 22 not otherwise being secured to the housing 12 intermediate the outboard ends 36 of the arms 32.
- a first, nonload-bearing projection 38 extends from the outboard end 36 of one of the arms 32 of each beam contact 22 to provide a first land 40 to which a respective external lead (not shown) may be connected. Threaded fasteners 41 pass through and support the respective land 40.
- a second, nonload-bearing projection 42 extends from the outboard end 36 of the other one of the arms 32 of each beam contact 22 to provide a second land 44 to which the respective lead of a diagnostic resistor 46 may be attached, for use by diagnostic means in the manner known to one of ordinary skill in the art.
- each cantilevered beam contact 22 achieves greater elastic travel through contact flexure both in bending along the length of its cantilevered portion 24, and in torsion in each of its lateral arms 32.
- the spring rate of the cantilevered portion 24 of each beam contact 22 is balanced with the torsional spring rate of its lateral arms 32 so that each experiences a quantitatively-similar amount of elastic strain for a given amount of travel of the beam contact's free end 30.
- the greater elastic travel of the cantilevered beam contact's free end 30 provides greater contact dwell while further ensuring greater reliability through lessened contact susceptibility to fatigue.
- each arm 32 "curls back" in the direction in which the cantilevered portion 24 of the beam contact 22 extends. This curling back of the outboard end 36 of each arm 32 further reduces the possibility of a fatigue failure of the beam contact 22 proximate to the point at which each of its lateral arms 32 is secured to the housing 12, i.e., near each arm's outboard end 36. While the preferred embodiment of the invention has been disclosed, it should be appreciated that the invention is susceptible of modification without departing from the spirit of the invention or the scope of the subjoined claims.
- the acceleration sensor described hereinabove features a pair of opposed cantilevered beam contacts 22 constructed in accordance with the invention
- the sensor may alternatively feature a single beam contact 22 constructed in accordance with the invention in combination with an electrically-conductive surface of the passage 14 to form the "contacts" to be bridged by the sensing mass 18 when it reaches its second position within the passage 14.
Landscapes
- Pressure Sensors (AREA)
- Switches Operated By Changes In Physical Conditions (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8505232A JPH09503336A (en) | 1994-07-18 | 1995-07-18 | Sensor with laterally supported beam contacts |
KR1019960701047A KR960705332A (en) | 1994-07-18 | 1995-07-18 | SENSOR WITH LATERALLY-SUPPORTED BEAM CONTACTS |
EP95927244A EP0719444A4 (en) | 1994-07-18 | 1995-07-18 | Sensor with laterally-supported beam contacts |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/276,450 | 1994-07-18 | ||
US08/276,450 US5471021A (en) | 1994-07-18 | 1994-07-18 | Acceleration sensor with laterally-supported beam contacts |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996002927A1 true WO1996002927A1 (en) | 1996-02-01 |
Family
ID=23056714
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1995/009034 WO1996002927A1 (en) | 1994-07-18 | 1995-07-18 | Sensor with laterally-supported beam contacts |
Country Status (6)
Country | Link |
---|---|
US (1) | US5471021A (en) |
EP (1) | EP0719444A4 (en) |
JP (1) | JPH09503336A (en) |
KR (1) | KR960705332A (en) |
CA (1) | CA2170292A1 (en) |
WO (1) | WO1996002927A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4301928A1 (en) * | 1993-01-25 | 1994-07-28 | Siemens Nixdorf Inf Syst | Conductive paint contact surface |
JP2003149263A (en) * | 2001-11-14 | 2003-05-21 | Mitsubishi Electric Corp | Acceleration-detecting apparatus |
US20150059430A1 (en) * | 2012-04-20 | 2015-03-05 | Panasonic Intellectual Property Management Co., Ltd. | Inertial force sensor |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3272949A (en) * | 1964-08-14 | 1966-09-13 | Allen Bradley Co | Bifurcated parallel contacts for relay |
US4221940A (en) * | 1979-01-12 | 1980-09-09 | General Motors Corporation | Sensor |
US4922065A (en) * | 1989-03-09 | 1990-05-01 | Automotive System Laboratory, Inc. | Temperature-compensating accelerometer |
US4932260A (en) * | 1988-06-27 | 1990-06-12 | Peter Norton | Crash sensing switch with suspended mass |
US5053588A (en) * | 1990-02-20 | 1991-10-01 | Trw Technar Inc. | Calibratable crash sensor |
US5149925A (en) * | 1990-09-05 | 1992-09-22 | Automotive Systems Laboratory, Inc. | Quick-response accelerometer |
US5210384A (en) * | 1990-08-23 | 1993-05-11 | Takata Corporation | Acceleration sensor with magnetic biased mass and encapsulated contact terminals and resistor |
US5374793A (en) * | 1992-08-25 | 1994-12-20 | Takata Corporation | Acceleration sensor |
-
1994
- 1994-07-18 US US08/276,450 patent/US5471021A/en not_active Expired - Fee Related
-
1995
- 1995-07-18 CA CA002170292A patent/CA2170292A1/en not_active Abandoned
- 1995-07-18 EP EP95927244A patent/EP0719444A4/en not_active Withdrawn
- 1995-07-18 JP JP8505232A patent/JPH09503336A/en active Pending
- 1995-07-18 WO PCT/US1995/009034 patent/WO1996002927A1/en not_active Application Discontinuation
- 1995-07-18 KR KR1019960701047A patent/KR960705332A/en not_active Application Discontinuation
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3272949A (en) * | 1964-08-14 | 1966-09-13 | Allen Bradley Co | Bifurcated parallel contacts for relay |
US4221940A (en) * | 1979-01-12 | 1980-09-09 | General Motors Corporation | Sensor |
US4932260A (en) * | 1988-06-27 | 1990-06-12 | Peter Norton | Crash sensing switch with suspended mass |
US4922065A (en) * | 1989-03-09 | 1990-05-01 | Automotive System Laboratory, Inc. | Temperature-compensating accelerometer |
US5053588A (en) * | 1990-02-20 | 1991-10-01 | Trw Technar Inc. | Calibratable crash sensor |
US5210384A (en) * | 1990-08-23 | 1993-05-11 | Takata Corporation | Acceleration sensor with magnetic biased mass and encapsulated contact terminals and resistor |
US5149925A (en) * | 1990-09-05 | 1992-09-22 | Automotive Systems Laboratory, Inc. | Quick-response accelerometer |
US5374793A (en) * | 1992-08-25 | 1994-12-20 | Takata Corporation | Acceleration sensor |
Non-Patent Citations (1)
Title |
---|
See also references of EP0719444A4 * |
Also Published As
Publication number | Publication date |
---|---|
EP0719444A4 (en) | 1998-05-13 |
JPH09503336A (en) | 1997-03-31 |
CA2170292A1 (en) | 1996-02-01 |
US5471021A (en) | 1995-11-28 |
EP0719444A1 (en) | 1996-07-03 |
KR960705332A (en) | 1996-10-09 |
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