Dual action safety seat belt retractor

Claim 2

In a vehicle safety seat belt system, the combination comprising: a. a support having a base and two walls extending therefrom; b. a shaft journaled on the support and adapted for connection to a seat belt, said shaft being rotatable in a winding direction and in the opposite unwind direction, said shaft having a first gear on one end thereof; c. a biasing member connected to the support and to the shaft, urging it to rotate in its winding direction; d. a ratchet wheel fixed to the rotatable shaft; e. a pawl mounted pivotally on the support for engagement with the ratchet wheel, said pawl being movable between a normally unlocked position and a locked position for engagement with the ratchet wheel to stop rotation of the shaft in its unwind direction; f. a first normally stationary arm which is movable upon actuation for urging the pawl into locking engagement with the ratchet wheel and which has a contact portion unconnected to but adapted to contact said pawl for actuating said pawl, thereby permitting said pawl to also pivot separate from said first arm; g. a second normally stationary arm which is movable upon actuation for urging the pawl independent of said first arm into locking engagement with the ratchet wheel and which has a contact portion unconnected to but adapted to contact said pawl for actuating said pawl, thereby permitting said pawl to also pivot separate from said second arm; h. a first normally stationary inertial device to which the first arm is attached, said inertial device comprising a plate rotatable within allowable limits about said shaft, said late supporting an inertial wheel and a second gear, said second gear adapted to engage said first gear, whereby in response to rotation of the shaft at acceleration exceeding a predetermined rate, displacement of the plate occurs, causing the arm to urge the pawl into locking engagement with the ratchet; i. a second inertial device, movable in response to acceleration or deceleration of the vehicle to which the support is attached, which actuates the second movable arm and independently urges the pawl into locking engagement with the ratchet wheel, whereby actuation of either inertial device independently locks the shaft, preventing extension of the seat belt attached thereto.

Claim 3

The combination of claim 1 wherein the ratchet wheel is fixed to a portion of the shaft extending beyond one journal in one wall, for rotation outside of the support adjacent to the wall, and wherein the pawl is mounted pivotally on this wall, outside of the support, for engagement with the ratchet wheel.

Claim 4

The combination of claim 1 wherein a pivot block is fixedly positioned on the outside wall, said block having a groove in its upper surface perpendicular to the wall, and the pawl with a pivoting edge is positioned with its pivoting edge resting in the groove to allow the pawl to pivot therein through an angle from its normally disengaged position to its engaged position with the ratchet wheel.

Claim 5

The combination of claim 3 wherein the pawl has a cylindrical stub, aligned wih the pivoting edge, which extends into a corresponding cylindrical opening in the support wall for limited rotation therein as the pawl is moved in and out of engagement with the ratchet wheel.

Claim 6

In a vehicle safety seat belt system, the combination comprising: a. a support having a base and two suppOrt walls extending therefrom; b. a shaft having two ends journaled on the support and adapted for connection to a seat belt, said shaft being rotatable in a winding direction and in the opposite unwind direction, said shaft having a first gear on one end thereof; c. a biasing member connected to the support and to the shaft, urging it to rotate in a winding direction; d. a ratchet wheel fixed to a rotatable shaft; e. a pawl mounted pivotally on the support for engagement with the ratchet wheel, said pawl being movable between a normally unlocked position and a locked position for engagement with the ratchet wheel to stop rotation of the shaft in its unwind direction, a portion of said pawl, extending through one support wall, angled for motion substantially parallel to the outside surface of the wall, as the pawl is moved between its locked and unlocked positions, said extending portion of said pawl having a first actuation member and a second actuation member; f. a first normally stationary inertial device biased to its normally stationary position and having a first arm for contacting said first actuation member of said extending portion of the pawl extending through the support wall, said first arm unconnected to but adapted to contact said first actuation member of said pawl, thereby permitting said pawl to also pivot separate from said first arm, said inertial device comprising a plate, said plate being rotatable to a limited degree about the shaft, and retained adjacent to the support wall by a first gear fixed to one end of the shaft, contiguous with the outer surface of the plate; said plate additionally supporting a rotatable inertial wheel carrying a second gear concentrically fixed thereto for engagement with the first gear, whereby in response to rotation of the shaft at acceleration exceeding a predetermined rate, angular displacement of the plate against its bias occurs, causing the arm to urge the pawl into engagement with the ratchet wheel; g. a second inertial device movable in response to acceleration or deceleration of the vehicle to which the support is attached, which actuates a second movable arm for contacting said second actuation member of said extending portion of said pawl and urging the pawl independent of said first arm into locking engagement with the ratchet wheel, said second arm unconnected to but adapted to contact said second actuation member of said pawl, thereby permitting said pawl to also pivot separate from said second arm, whereby actuation of either inertial device independently locks the shaft, preventing extension of the seat belt attached thereto.

Claim 7

In a vehicle safety seat belt system, the combination comprising: a. a support having a base and two suppOrt walls extending therefrom; b. a shaft having two ends journaled on the support and adapted for connection to a seat belt, said shaft being rotatable in a winding direction and in the opposite unwind direction, said shaft having a first gear on one end thereof; c. a biasing member connected to the support and to the shaft, urging it to rotate in a winding direction; d. a ratchet wheel fixed to a rotatable shaft; e. a pawl mounted pivotally on the support for engagement with the ratchet wheel, said pawl being movable between a normally unlocked position and a locked position for engagement with the ratchet wheel to stop rotation of the shaft in its unwind direction, a portion of said pawl, extending through one support wall, angled for motion substantially parallel to the outside surface of the wall, as the pawl is moved between its locked and unlocked positions, said extending portion of said pawl having a first actuation member and a second actuation member; f. a first normally stationary inertial device biased to its normally stationary position and having a first arm for contacting said first actuation member of said extending portion of the pawl extending through the support wall, said first arm unconnected to but adapted to contact said first actuation member of said pawl, thereby permitting said pawl to also pivot separate from said first arm, said inertial device comprising a plate, said plate being rotatable to a limited degree about the shaft, and retained adjacent to the support wall by a first gear fixed to one end of the shaft, contiguous with the outer surface of the plate; said plate additionally supporting a rotatable inertial wheel carrying a second gear concentrically fixed thereto for engagement with the first gear, whereby in response to rotation of the shaft at acceleration exceeding a predetermined rate, angular displacement of the plate against its bias occurs, causing the arm to urge the pawl into engagement with the ratchet wheel; g. a second inertial device movable in response to acceleration or deceleration of the vehicle to which the support is attached, which actuates a second movable arm for contacting said second actuation member of said extending portion of said pawl and urging the pawl independent of said first arm into locking engagement with the ratchet wheel, said second arm unconnected to but adapted to contact said second actuation member of said pawl, thereby permitting said pawl to also pivot separate from said second arm, whereby actuation of either inertial device independently locks the shaft, preventing extension of the seat belt attached thereto.

Claim 8

The combination of claim 5 wherein the inertial wheel with attached gear rotates on a spindle normal to the surface of the rotatable plate and fixed thereto.

Claim 9

The combination of claim 5 wherein the rotatable plate includes a rigid housing extending about the inertial wheel and its attached gear, said housing having parallel walls with opposing openings in each wall into which a shaft for the wheel is journaled and supported.

Claim 10

The combination of claim 5 wherein the first inertial device is supported on the outside wall by the shaft, for limited rotation thereon, and the second inertial device is supported on the same outside wall below the first inertial device, with the arm of the first inertial device extending downwardly to actuate the pawl and with the arm of the second inertial device extending upwardly to independently actuate the same pawl.

Claim 11

The combination of claim 5 wherein at least one ratchet wheel fixed to the shaft is disposed between the two support walls and adjacent to one of the walls, with the inertial devices supported on the outside of one of the walls, and with the pawl extending pivotally between both walls for engagement with the ratchet wheel; said pawl having a projecting member extending through the wall supporting the inertial devices for contact with the arms of said devices, whereby the pawl is actuated into locking engagement with the ratchet wheel when the projecting member is urged by an arm of either inertial device independent of the other.

Claim 12

The combination of claim 5 wherein the pawl is mounted for engaging a ratchet wheel adjacent to the inner surface of the support wall, which wall carries the inertial devices on its outer surface, the pawl being fixed to a rotatable shaft journaled in the wall, said shaft having a projecting member adjacent to the outer surface of the wall for contact with, and actuation by, the arms of the inertial devices supported on said outer surface of the support wall, for urging the pawl into engagement with the ratchet wheel.

Claim 13

In a vehicle safety seat belt system, the combination comprising: a. a support having a base and two walls extending therefrom; b. a shaft journaled on the support and adapted for connection to a seat belt, said shaft being rotatable in a winding direction and in an opposite unwind direction, said shaft having a first gear to one end thereof; c. a biasing member connected to the support and to the shaft, urging it to rotate in its winding direction; d. a ratchet wheel fixed to the rotatable shaft; e. a pawl mounted pivotally in the support walls for engagement with the ratchet wheel, said pawl being movable between a normally unlocked position and a locked position by engagement with the ratchet wheel to stop rotation of the shaft in its unwind direction, a portion of said pawl, extending through one support wall, angled for motion substantially parallel to the outside surface of the wall, as the pawl moves betweeen its locked and unlocked positions, said extending portion of said pawl having a first actuation member and a second actuation member; f. a first normally stationary arm which is movable upon actuation and which has a contact portion for actuating said first actuation member of said pawl for urging the pawl into locking engagement with the ratchet wheel, said first arm unconnected to but adapted to contact said first actuation member of said pawl, thereby permitting said pawl to also pivot separate from said first arm; g. a second normally stationary arm which is movable upon actuation and which has a contact portion actuating said second actuation member of said pawl for urging the pawl independent of said first arm into locking engagement with the ratchet wheel, said second arm unconnected to but adapted to contact said second actuation member of said pawl, thereby permitting said pawl to also pivot separate from said second arm; h. a first normally stationary inertial device to which the first arm is fixedly attached, said inertial device comprising a plate rotatable within allowable limits about said shaft, said plate supporting an inertial wheel and a second gear, said second gear adapted to engage said first gear, whereby, in response to rotation of the shaft with acceleration exceeding a predetermined rate, displacement of the plate occurs, causing the arm to urge the pawl into locking engagement with the ratchet wheel; i. a second inertial device, movable in response to acceleration or deceleration of a vehicle to which the support is attached, which actuates the second movable arm and independently urges the pawl into locking engagement with the ratchet, said second inertial device comprising a pendulum, free to swing in all directions, said pendulum being suspended on a rigid rod which passes upwardly from the pendulum through an opening in a horizontal plate fixed to the outer support wall, said opening having sufficient diameter so as not to appreciably inhibit the motion of the pendulum; said rigid rod topped with and perpendicular to a disc, having a diameter greater than the opening for the shaft; said disc resting on the upper surface of the horizontal plate to support the rod and attached pendulum; said movable arm of this second inertial device lying horizontally above the disc with one end hinged for motion in an arc parallel to the outEr surface of the support wall, said hinge being fixed to the support wall; the other end of the arm in its normal position is adjacent to the pawl in its unlocked position whereby any movement of the pendulum resulting from acceleration or deceleration of a vehicle to which the support is attached, raises the disc by rocking it to a point near its periphery, thereby raising the arm above, and independently moving the pawl into locking engagement with the ratchet wheel.

Claim 14

In a vehicle safety seat belt system, the combination comprising: a. a support having a base and two walls extending therefrom; b. a shaft journaled on the support and adapted for connection to a seat belt, said shaft being rotatable in a winding direction and in an opposite unwind direction, said shaft having a first gear to one end thereof; c. a biasing member connected to the support and to the shaft, urging it to rotate in its winding direction; d. a ratchet wheel fixed to the rotatable shaft; e. a pawl mounted pivotally in the support walls for engagement with the ratchet wheel, said pawl being movable between a normally unlocked position and a locked position by engagement with the ratchet wheel to stop rotation of the shaft in its unwind direction, a portion of said pawl, extending through one support wall, angled for motion substantially parallel to the outside surface of the wall, as the pawl moves betweeen its locked and unlocked positions, said extending portion of said pawl having a first actuation member and a second actuation member; f. a first normally stationary arm which is movable upon actuation and which has a contact portion for actuating said first actuation member of said pawl for urging the pawl into locking engagement with the ratchet wheel, said first arm unconnected to but adapted to contact said first actuation member of said pawl, thereby permitting said pawl to also pivot separate from said first arm; g. a second normally stationary arm which is movable upon actuation and which has a contact portion actuating said second actuation member of said pawl for urging the pawl independent of said first arm into locking engagement with the ratchet wheel, said second arm unconnected to but adapted to contact said second actuation member of said pawl, thereby permitting said pawl to also pivot separate from said second arm; h. a first normally stationary inertial device to which the first arm is fixedly attached, said inertial device comprising a plate rotatable within allowable limits about said shaft, said plate supporting an inertial wheel and a second gear, said second gear adapted to engage said first gear, whereby, in response to rotation of the shaft with acceleration exceeding a predetermined rate, displacement of the plate occurs, causing the arm to urge the pawl into locking engagement with the ratchet wheel; i. a second inertial device, movable in response to acceleration or deceleration of a vehicle to which the support is attached, which actuates the second movable arm and independently urges the pawl into locking engagement with the ratchet, said second inertial device comprising a pendulum, free to swing in all directions, said pendulum being suspended on a rigid rod which passes upwardly from the pendulum through an opening in a horizontal plate fixed to the outer support wall, said opening having sufficient diameter so as not to appreciably inhibit the motion of the pendulum; said rigid rod topped with and perpendicular to a disc, having a diameter greater than the opening for the shaft; said disc resting on the upper surface of the horizontal plate to support the rod and attached pendulum; said movable arm of this second inertial device lying horizontally above the disc with one end hinged for motion in an arc parallel to the outEr surface of the support wall, said hinge being fixed to the support wall; the other end of the arm in its normal position is adjacent to the pawl in its unlocked position whereby any movement of the pendulum resulting from acceleration or deceleration of a vehicle to which the support is attached, raises the disc by rocking it to a point near its periphery, thereby raising the arm above, and independently moving the pawl into locking engagement with the ratchet wheel.

Claim 15

The combination of claim 11 in which the disc has a centrally located depression corresponding to a protruding nodule beneath the second arm, and the opening in the horizontal plate has a raised collar extending upwardly from the plate, with the disc resting on the circular edge of this collar rather than directly on the surface of the horizontal plate, said opening and surrounding collar being sized to permit the pendulum to swing through an arc of at least about 40*.

Claim 16

The combination of claim 11 wherein the movable plate of the first inertial device, and the components of the second inertial device with the exception of the pendulum are fabricated of polymeric material for lightness and quick response.

Claim 17

In a vehicle safety seat belt system, the combination comprising: a. a support having a base and two support walls extending therefrom; b. a shaft journaled on the support and adapted for connection to a seat belt, said shaft being rotatable in a winding direction and in the opposite unwind direction; c. a biasing member connected to the support and to the shaft, urging it to rotate in its winding direction; d. a ratchet wheel fixed to the rotatable shaft; e. a pawl mounted pivotally in the support walls for engagement with the ratchet wheel, said pawl being movable between a normally unlocked position and a locked position for engagement with the ratchet wheel to stop rotation of the shaft in its unwind direction a portion of said pawl, extending through one support wall, angled for motion substantially paralel to the outside surface of the wall, as the pawl moves between its locked and unlocked positions, said extending portion having a first actuation member and a second actuation member; f. a first normally stationary inertial device biased to its normally stationary position and having a first arm for contacting said first actuation member of said extending portion of the pawl extending through the support wall, said first arm unconnected to but adapted to contact said first actuation member of said pawl, thereby permitting said pawl to also pivot separate from said first arm, said inertial device comprising a plate, said plate being rotatable to a limited degree about the shaft, and retained adjacent to the support wall by a first gear fixed to one end of the shaft, contiguous with the outer surface of the plate; said plate additionally supporting a rotatable inertial wheel carrying a second gear concentrically fixed thereto for engagement with the first gear, whereby in response to rotation of the shaft with acceleration exceeding a predetermined rate, angular displacement of the plate against the bias occurs, causing the first arm to urge the pawl into engagement with the ratchet wheel; g. a second inertial device, movable in response to acceleration or deceleration of a vehicle to which the support is attached, which actuates a second movable arm for contacting said second actuation member of said extending portion of said pawl and urging the pawl independent of said first arm into locking engagement with the ratchet wheel, said second arm unconnected to but adapted to contact said second actuation member of said pawl, thereby permitting said pawl to also pivot separate from said second arm, whereby actuation of either inertial device independently locks the shaft, preventing extension of the seat belt attached thereto, said second inertial device comprising a pendulum, free to swing in all directions, said pendulum being suspendeD on a rigid rod which passes upwardly from the pendulum through an opening in a horizontal plate fixed to the outer support wall, said opening having sufficient diameter so as not to inhibit the motion of the pendulum; said rigid rod topped with, and perpendicular to a disc, having a diameter greater than the opening for the shaft; said disc resting on the upper surface of the horizontal plate to support the rod and attached pendulum; said movable arm of this second inertial device lying horizontally above the disc with one end hinged for motion in an arc parallel to the outer surface of the support wall, said hinge being fixed to the support wall; the other end of the arm is in its normal position is adjacent to the pawl in its disengaged position, whereby any movement of the pendulum resulting from acceleration or deceleration of a vehicle to which the support is attached, raises the disc by rocking it to a point on its periphery, thereby raising the arm above, and independently moving the pawl into locking engagement with the ratchet wheel.

Claim 18

In a vehicle safety seat belt system, the combination comprising: a. a support having a base and two support walls extending therefrom; b. a shaft journaled on the support and adapted for connection to a seat belt, said shaft being rotatable in a winding direction and in the opposite unwind direction; c. a biasing member connected to the support and to the shaft, urging it to rotate in its winding direction; d. a ratchet wheel fixed to the rotatable shaft; e. a pawl mounted pivotally in the support walls for engagement with the ratchet wheel, said pawl being movable between a normally unlocked position and a locked position for engagement with the ratchet wheel to stop rotation of the shaft in its unwind direction a portion of said pawl, extending through one support wall, angled for motion substantially paralel to the outside surface of the wall, as the pawl moves between its locked and unlocked positions, said extending portion having a first actuation member and a second actuation member; f. a first normally stationary inertial device biased to its normally stationary position and having a first arm for contacting said first actuation member of said extending portion of the pawl extending through the support wall, said first arm unconnected to but adapted to contact said first actuation member of said pawl, thereby permitting said pawl to also pivot separate from said first arm, said inertial device comprising a plate, said plate being rotatable to a limited degree about the shaft, and retained adjacent to the support wall by a first gear fixed to one end of the shaft, contiguous with the outer surface of the plate; said plate additionally supporting a rotatable inertial wheel carrying a second gear concentrically fixed thereto for engagement with the first gear, whereby in response to rotation of the shaft with acceleration exceeding a predetermined rate, angular displacement of the plate against the bias occurs, causing the first arm to urge the pawl into engagement with the ratchet wheel; g. a second inertial device, movable in response to acceleration or deceleration of a vehicle to which the support is attached, which actuates a second movable arm for contacting said second actuation member of said extending portion of said pawl and urging the pawl independent of said first arm into locking engagement with the ratchet wheel, said second arm unconnected to but adapted to contact said second actuation member of said pawl, thereby permitting said pawl to also pivot separate from said second arm, whereby actuation of either inertial device independently locks the shaft, preventing extension of the seat belt attached thereto, said second inertial device comprising a pendulum, free to swing in all directions, said pendulum being suspendeD on a rigid rod which passes upwardly from the pendulum through an opening in a horizontal plate fixed to the outer support wall, said opening having sufficient diameter so as not to inhibit the motion of the pendulum; said rigid rod topped with, and perpendicular to a disc, having a diameter greater than the opening for the shaft; said disc resting on the upper surface of the horizontal plate to support the rod and attached pendulum; said movable arm of this second inertial device lying horizontally above the disc with one end hinged for motion in an arc parallel to the outer surface of the support wall, said hinge being fixed to the support wall; the other end of the arm is in its normal position is adjacent to the pawl in its disengaged position, whereby any movement of the pendulum resulting from acceleration or deceleration of a vehicle to which the support is attached, raises the disc by rocking it to a point on its periphery, thereby raising the arm above, and independently moving the pawl into locking engagement with the ratchet wheel.

Claim 19

In a vehicle safety seat belt system, the combination comprising: a. a support having a base and two support walls extending therefrom; b. a shaft journaled on the support and adapted for connection to a seat belt, said shaft being rotatable in a winding direction and in the opposite unwind direction; c. a biasing member connected to the support and to the shaft, urging it to rotate in its winding direction; d. a ratchet wheel fixed to the rotatable shaft adjacent to the outer surface of the support wall; e. a pawl mounted pivotally on the support walls for engagement with the ratchet wheel, said pawl being movable between a normally unlocked position and a locked position by engagement with the ratchet wheel, to stop rotation of the shaft in its unwind direction; f. a first normally stationary inertial device biased to its normally stationary position and having a first arm, said first arm having a contact portion unconnected to but adapted to contact said pawl for actuating said pawl, thereby permitting said pawl to also pivot separate from said first arm, aid inertial device comprising a plate, said plate being rotatable to a limited degree about the shaft, and retained adjacent to the ratchet wheel by a first gear fixed to the end of the shaft, contiguous with the outer surface of the plate; said plate additionally supporting a rotatable inertial wheel carrying a second gear concentrically fixed thereto for engagement with the first gear, whereby in response to rotation of the shaft at acceleration exceeding a predetermined rate, angular displacement of the plate against the bias occurs, causing the first arm to urge the pawl into engagement with the ratchet wheel; g. a second inertial device, movable in response to acceleration or deceleration of a vehicle to which the support is attached, which actuates a second movable arm, said second arm having a contact portion for contacting said pawl and urging the pawl independent of said first arm into locking engagement with the ratchet wheel, said second arm being unconnected to but adapted to contact said pawl, thereby permitting said pawl to also pivot separate from said second arm, said second inertial device comprising a pendulum, free to swing in all directions, said pendulum being suspended on a rigid rod which passes upwardly from the pendulum through an opening in a horizontal plate fixed to the outer support wall, said opening having sufficient diameter so as not to inhibit the motion of the pendulum; said rigid rod topped with, and perpendicular to a disc, having a diameter greater than the opening for the shaft; said disc resting on the upper surface of the horizontal plate to support the rod and attached pendulum; said movable arm of this second inertial device lying horizontally above the disc and having a pivot point at one end for motion of said movable arm in an arc parallel to the outer surface of the support wall, said pivot point beIng fixed to the support wall; the other end of the arm in its normal position being adjacent to the pawl in its disengaged position, whereby any movement of the pendulum resulting from acceleration or deceleration of a vehicle to which the support is attached, raises the disc by rocking it to a point on its periphery, thereby raising the arm above, and independently moving the pawl into locking engagement with the ratchet wheel.

Claim 20

In a vehicle safety seat belt system, the combination comprising: a. a support having a base and two support walls extending therefrom; b. a shaft journaled on the support and adapted for connection to a seat belt, said shaft being rotatable in a winding direction and in the opposite unwind direction; c. a biasing member connected to the support and to the shaft, urging it to rotate in its winding direction; d. a ratchet wheel fixed to the rotatable shaft adjacent to the outer surface of the support wall; e. a pawl mounted pivotally on the support walls for engagement with the ratchet wheel, said pawl being movable between a normally unlocked position and a locked position by engagement with the ratchet wheel, to stop rotation of the shaft in its unwind direction; f. a first normally stationary inertial device biased to its normally stationary position and having a first arm, said first arm having a contact portion unconnected to but adapted to contact said pawl for actuating said pawl, thereby permitting said pawl to also pivot separate from said first arm, aid inertial device comprising a plate, said plate being rotatable to a limited degree about the shaft, and retained adjacent to the ratchet wheel by a first gear fixed to the end of the shaft, contiguous with the outer surface of the plate; said plate additionally supporting a rotatable inertial wheel carrying a second gear concentrically fixed thereto for engagement with the first gear, whereby in response to rotation of the shaft at acceleration exceeding a predetermined rate, angular displacement of the plate against the bias occurs, causing the first arm to urge the pawl into engagement with the ratchet wheel; g. a second inertial device, movable in response to acceleration or deceleration of a vehicle to which the support is attached, which actuates a second movable arm, said second arm having a contact portion for contacting said pawl and urging the pawl independent of said first arm into locking engagement with the ratchet wheel, said second arm being unconnected to but adapted to contact said pawl, thereby permitting said pawl to also pivot separate from said second arm, said second inertial device comprising a pendulum, free to swing in all directions, said pendulum being suspended on a rigid rod which passes upwardly from the pendulum through an opening in a horizontal plate fixed to the outer support wall, said opening having sufficient diameter so as not to inhibit the motion of the pendulum; said rigid rod topped with, and perpendicular to a disc, having a diameter greater than the opening for the shaft; said disc resting on the upper surface of the horizontal plate to support the rod and attached pendulum; said movable arm of this second inertial device lying horizontally above the disc and having a pivot point at one end for motion of said movable arm in an arc parallel to the outer surface of the support wall, said pivot point beIng fixed to the support wall; the other end of the arm in its normal position being adjacent to the pawl in its disengaged position, whereby any movement of the pendulum resulting from acceleration or deceleration of a vehicle to which the support is attached, raises the disc by rocking it to a point on its periphery, thereby raising the arm above, and independently moving the pawl into locking engagement with the ratchet wheel.