Abstract: A shock sensor has a sensing mass mounted on a metallic reed or spring which, under the influence of a crash-induced acceleration, drives the spring against a contact to close an electrical circuit. The contact end of the spring is twisted to be oriented with respect to the fixed contact at an angle of 60 degrees out of the plane containing the spring. The sensor is oriented such that the acceleration force is approximately normal to the plane containing the spring. The angled contact increases reliability, reduces closure signal noise, and increases contact dwell time. Dwell time can be further enhanced for high shock loads by providing a two stage mass spring system. A second mass/spring combination is arranged so the motion of the second mass, after the first reed has made electrical contact, holds the contact closed.

Abstract: A shunt is pivotally mounted to form a pendulum positioned between a reed switch and a magnet. The shunt is formed of ferromagnetic material and is mounted such that as long as it remains between the reed switch and the magnet the reed switch remains open. The shunt is held or biased between the magnet and the reed switch by the force of the magnetic attraction between the shunt and the magnet. The mass of the shunt acts as both a tilt sensor which responds to gravity and an accelerometer sensitive to crash-induced accelerations. The reed switch, magnet and shunt are mounted in a housing which positions the reed switch and magnet and controls the maximum range of motion of the pendulum-mounted shunt. An alternative embodiment employs a subassembly which includes a magnet, a shunt, and a selectively positioned mass, the subassembly is mounted to pivot over a reed switch. The magnet is positioned on or very near the pivot axis. The shunt is positioned further from the pivot axis toward the reed switch.

Abstract: A bidirectional shock sensor is constructed from a reed switch positioned between two shock sensing magnets. Each magnet is an annular ring which travels parallel to the reed switch reeds on a shaft spaced in a direction perpendicular to the axis of the reed switch. A spring pre-loads a first magnet against a first stop. A second spring pre-loads a second magnet against a second stop. The direction of travel of the first and second magnets is opposite and the first and second stops are positioned at opposite ends and on opposite sides of the reed switch. The magnets and the shafts on which they travel are positioned on identical housings which are arranged as mirror images with the reed switch positioned therebetween.

Abstract: A ferromagnetic shunt is pivotally mounted to a housing to form a pendulum which swings between a reed switch and a magnet. As long as the shunt remains between the reed switch and the magnet the reed switch remains open. The shunt is held or biased between the magnet and the reed switch by the force of the magnetic attraction between the shunt and the magnet. The mass of the shunt acts as both a tilt sensor which responds to gravity and an accelerometer sensitive to crash-induced accelerations. The reed switch, magnet and shunt are mounted in a housing which positions the reed switch and magnet and controls the maximum range of motion of the shunt. The magnet is located between two sidewardly spaced pendulum arms, which allow the shunt to swing out from between the reed switch and the magnet in two opposite directions.

Abstract: A shock sensor has a housing with two portions. A first portion resiliently engages a reed switch which has staple formed leads. A second portion extends adjacent one of the reed switch leads and has modular components which permit consistent shock-sensing results to be obtained from reed switches of varying sensitivity by selection of appropriate components. The second portion is a closed-ended hollow tube in which a bobbin with a centrally located guide bar is inserted. A first disk extends outwardly from the guide bar. A self-test coil is positioned on the bar between the first disk and a second disk. A biasing spring extends between the closed end of the tube and the magnet, which is mounted on the bar. The magnet is abutted against a second disk which extends from the bar. The second disk positions the actuation magnet with respect to the reed switch when it is in its non-actuated position.

Abstract: A housing has a vertical subframe in which is mounted one or more reed switches. A magnet is mounted to a carriage which is mounted about the reed switch by a two-degree-of-freedom joint. The carriage forms a cup with a base aperture which surrounds the subframe. The aperture defines a semi-spherical surface which rides on a semi-spherical surface at the base of the subframe. A shell is fixed to the housing and the inside surface of the shell has a semi-spherical surface concentric with the semi-spherical surfaces defined by the annulus of the aperture and the semi-spherical base of the subframe. The carriage has semi-spherical surface portions which engage the shell interior and is thereby constrained to rotate about the point of concentricity common to the shell, the carriage, the annular aperture, and the semi-spherical base of the subframe. The carriage is biased to an upright position by springs which extend between the base of the housing and an upper lip of the carriage.

Abstract: A shock sensor achieving the advantages of extended minimum dwell and extended total dwell employs a reed switch in a housing mounted coaxial to the reed switch. The shock sensor employs a magnet of cylindrical shape, which is coaxial with the reed switch and slidably mounted to activate the reed switch. The shape of the activation magnet, which also serves as an acceleration detecting mass, is that of a cylindrical shell which extends along the axis of the reed switch. The shell has a ring portion extending radially inward and of short axial extent on the end of the magnet which lags in activation. A spring extends between an abutment and the magnet within the shell. When the shock sensor is subjected to an acceleration, the magnet is moved by the acceleration force from a non-activating position. Further extending the activation dwell time of the sensor and, in addition, providing an extended minimum dwell time, is the shape of the magnetic field created by the ring at the first abutting end of the magnet.

Abstract: A shock sensor has a housing defining an axially extending bore, a reed switch is centered within the bore by means of its axially extending leads and a transverse section of the housing which has an axially extending hole which centers one of the leads of the reed switch with the housing. The other lead of the reed switch is centered by a first retainer, which is fixed within the bore to align the reed switch within the housing with the axis of the housing. An activation magnet, is slidably mounted within the bore of the housing, and has a central hole passing over one of the axially extending leads. The magnet is biased by a spring away from the end activation region of the reed switch, which is near an end of the glass capsule which encloses the reed switch. The spring biases the activation magnet against a second retainer so that when the housing is not undergoing acceleration the activation magnet is biased to a position where the switch is not activated.

Abstract: A testing device (11) is applied to an acceleration shock sensor (10) of the type having a reed switch (24) that operates such that the net mass of a magnet (40) is accelerated against a spring (50) upon vehicle impact or rapid deceleration of the vehicle. The change in magnet (40) position causes a change in the magnetic field that activates the reed switch (24). The testing device (11) includes an electromagnetic coil (90) mounted in an area of minimal reed switch (24) sensitivity. The electromagnetic coil (90) is connected to be capable of providing a current flow that creates a magnetic field that opposes the magnetic field of the magnet (40). Upon energizing of the coil (90), the magnet (40) is urged to accelerate in a manner that emulates the acceleration of the magnet (40) caused by vehicle collision.

Abstract: An extended dwell shock sensing device (10) is constructed to operate in two stages. A carriage (34) that includes a magnet (40) is slidably mounted between a first abutment (20) and a second abutment (22). The carriage (34) also includes a cradle (52) in which a non-magnetic mass (54) is slidably mounted between a first wall (53) and a second wall (55). At a rest position, the carriage (34) is biased away from the second abutment (22) by a spring (50) and the non-magnetic mass (54) is biased away from the second wall (55) by a spring (58). A reed switch (24) is mounted to be responsive to the position of the magnet (40). Upon application of an acceleration force, the shock sensing device (10) operates in two stages. In a first stage, the carriage (34) travels to a position where it approaches the second abutment (22), and activates the reed switch (24). In a second stage, the non-magnetic mass (54) travels toward the second wall (55).