Seat belt locking mechanism and alarm system

Claim 2

An alarm system for a vehicle passenger seat belt comprising a drum, a belt engageable and lockable about a passenger, said belt having one end attached to and wound on said drum, locking means for preventing rotation of said drum after rotation of said drum a predetermined number of revolutions during belt unwind, said alarm system comprising an electrical alarm device and switching means for activating said alarm device, said switching means comprising a stationary switch contact, a movable switch contact and a switch operating means, said operating means comprising a member dispLaceable by rotation of said drum and supporting said movable contact for holding said movable contact in engagement with said stationary contact to activate said alarm device until a predetermined number of revolutions of said drum have occurred, wherein said stationary contact is mounted on an insulating plate, said plate being adjustable manually in the direction of travel of said movable contact to position said stationary contact relatively to said movable contact to preset the duration of activation of said alarm device during belt unwind, and wherein said member displaceable by rotation of said drum is a nut member threaded on a threaded shaft driven in unison with said drum, said switch operating means further comprising means preventing said nut member from rotating such that rotation of said shaft causes longitudinal displacement of said nut member, said movable switch contact being mounted on said nut member.

Claim 3

A seat belt locking mechanism comprising a frame, a first shaft rotatably mounted on said frame, a drum attached to said shaft for rotation therewith, a belt attached to said drum for winding thereon and unwinding therefrom, a ratchet wheel mounted on said first shaft for rotation therewith, a pawl pivotally mounted on said frame for engagement with said ratchet wheel, biasing means for urging said pawl into engagement with said ratchet wheel, a second shaft rotatably supported by said frame and having a threaded body portion and an unthreaded end portion, drive means for rotating said second shaft in unison with said first shaft, a bushing disposed about the unthreaded portion of said second shaft, friction drive means between said bushing and said unthreaded portion of the second shaft, a projecting abutment member dependent from said pawl to pivot said pawl away from engagement with said ratchet wheel, said abutment member being operable to cause engagement and disengagement of said pawl with said ratchet wheel as a result of longitudinal displacement of said bushing along the unthreaded portion of said second shaft, helicoidal spline connecting means between said bushing and said frame, a nut member threaded on the threaded portion of said second shaft, means preventing rotation of said nut member such that rotation of said second shaft cause said nut member to be longitudinally displaced, a coil spring disposed about said shaft and having an end engaging said nut member and the other end engaging said bushing such that when said spring is compressed as a result of said nut being disposed proximate said bushing said bushing is displaced longitudinally to a position whereby said abutment member disengages said pawl from said ratchet wheel and when said nut is displaced away from said bushing said frictional drive between the unthreaded portion of said second shaft and said bushing causes said bushing to rotate in unison with said shaft such as to be longitudinally displaced under the action of said spline connecting means between said bushing and said frame, thereby displacing said abutment member to cause disengagement of said pawl from said ratchet wheel.

Claim 4

A seat belt locking mechanism comprising a frame, a first shaft rotatably mounted on said frame, a drum attached to said shaft for rotation therewith, a belt attached to said drum for winding thereon and unwinding therefrom, a ratchet wheel mounted on said first shaft for rotation therewith, a pawl pivotally mounted on said frame for engagement with said ratchet wheel, biasing means for urging said pawl into engagement with said ratchet wheel, a second shaft rotatably supported by said frame and having a threaded body portion and an unthreaded end portion, drive means for rotating said second shaft in unison with said first shaft, a bushing disposed about the unthreaded portion of said second shaft, friction drive means between said bushing and said unthreaded portion of the second shaft, a projecting abutment member dependent from said pawl to pivot said pawl away from engagement with said ratchet wheel, said abutment member being operable to cause engagement and disengagement of said pawl with said ratchet wheel as a result of longitudinal displacement of said bushing along the unthreaded portion of said second shaft, helicoidal spline connecting means between said bushing and said frame, a nut member threaded on the threaded portion of said second shaft, means preventing rotation of said nut member such that rotation of said second shaft cause said nut member to be longitudinally displaced, a coil spring disposed about said shaft and having an end engaging said nut member and the other end engaging said bushing such that when said spring is compressed as a result of said nut being disposed proximate said bushing said bushing is displaced longitudinally to a position whereby said abutment member disengages said pawl from said ratchet wheel and when said nut is displaced away from said bushing said frictional drive between the unthreaded portion of said second shaft and said bushing causes said bushing to rotate in unison with said shaft such as to be longitudinally displaced under the action of said spline connecting means between said bushing and said frame, thereby displacing said abutment member to cause disengagement of said pawl from said ratchet wheel.

Claim 5

The seat belt locking mechanism of claim 2 wherein said drive means between said first shaft and said second shaft is a right angle drive, and said second shaft is disposed at an axis substantially perpendicular to the axis of said first shaft.

Claim 6

The seat belt locking mechanism of claim 3 wherein said right angle drive is a flexible drive.

Claim 7

The seat belt locking mechanism of claim 2 wherein said frictional drive comprises a resilient O-ring disposed in a peripheral groove on the unthreaded portion of said second shaft and yieldably engaging the internal bore of said bushing.

Claim 8

The seat belt locking mechanism of claim 2 wherein an electrically conductive switch contact is supported on said nut member for engagement with an elongated stationary switch contact dependent from said frame, and electrical circuit operable when said contacts are in engagement to give an alarm iNdicating that said belt is wound on the drum.

Claim 9

The seat belt locking mechanism of claim 6 wherein said elongated stationary contact is disposed in an insulated slide member manually adjustable longitudinally to preset the duration of said alarm as a function of the length of said belt remaining wound on said drum.

Claim 10

The alarm system of claim 6 further comprising a second switch in series in said circuit, said second switch being closed upon turning on the ignition of said vehicle.

Claim 11

The alarm system of claim 6 further comprising a second switch in series in said circuit, said second switch being normally open and closed upon a person sitting on the seat of said vehicle.

Claim 12

The alarm system of claim 1 further comprising second switching means in series with said first mentioned switching means, said second switching means being closed upon turning on the ignition of said vehicle.

Claim 13

The alarm system of claim 1 further comprising second switching means in series with said first mentioned switching means, said second switching means being normally open and closed upon a person sitting upon the seat of said vehicle.