Restraint system pretensioners

Various embodiments of restraint system pretensioning devices for use in land, air, and sea vehicles are described herein. In one embodiment, a seat unit for use in a military land vehicle or helicopter includes a stroking device that enables the seat to move downwardly in response to sudden movement. The seat unit also includes a seat belt or harness that extends around the occupant in the seat. Sudden movement of the seat in response to an explosion or hard landing causes a pretensioning assembly to automatically pretension the seat harness.

TECHNICAL FIELD

The following disclosure is directed generally to the field of personal restraints for use in vehicles and, more particularly, to the field of restraint system pretensioners for use in military land vehicles, air vehicles, and other vehicles.

BACKGROUND

Military land vehicles generally have a three-, four-, or five-point seat/shoulder belt or harness in one or more of the vehicle seats. Civilian vehicles generally have a three-point shoulder belt/lap belt harness. To minimize or reduce injury during a collision or rollover, both military and civilian vehicles have used seat harness pretensioners. In a typical pretensioner, sensors on the vehicle detect the acceleration and/or deceleration forces of a collision or rollover, causing the pretensioners to actuate. The pretensioners then tighten up the seat harness around the seated passenger or driver milliseconds before the actual full impact or rollover. The tightened harness holds the passenger securely into the seat, reducing impact and rebound injuries. These existing pretensioners can be relatively complicated designs because they rely on pyrotechnic devices or electric motors operating a belt retractor, each controlled by an electronic trigger.

Many military land vehicles are designed to resist the destructive forces of mines and improvised explosive devices (IEDs). These explosive devices create unique risks for military land vehicles. Detonation of a large explosive device can generate forces on the vehicle exceeding 100 g, causing the vehicle to accelerate violently upwardly. To reduce the forces on the vehicle crew during a detonation, some military vehicles, such as the Joint Light Tactical Vehicle (JLTV), Bradley Fighting Vehicle, and Mine Resistant Ambush Protected Vehicle (MRAP), have blast attenuating seats. Blast attenuating seats are often supported on shock absorbing materials or are mounted on a shock absorbing structure, such as a stroking device, that allows the seat to move downwardly during a blast.

Conventional harness pretensioning techniques are generally impractical with these types of blast attenuating seats, because the seats move relative to the vehicle body during the blast and the acceleration is largely vertical, rather than horizontal. In addition, conventional harness pretensioning systems typically use pyrotechnic devices, electric retractor motors, or electronic sensors, which can be complicated and costly.

In addition to land vehicles, passengers in helicopters are subjected to similar types of extreme forces during crashes or hard landings. Some helicopters also have seats mounted on a stroking device. The challenges presented in harness pretensioning with blast attenuation seats are also present in helicopter seats mounted on stroking devices.

DETAILED DESCRIPTION

The present disclosure describes various embodiments of restraint system pretensioners for use with personal restraint systems in land, air, and sea vehicles. In one embodiment, for example, a seat unit for use in a land vehicle or helicopter includes a stroking device that enables the seat to move relative to the vehicle in response to an explosion or hard landing. The seat unit also includes a tensioning web or belt that is integral with a harness that extends around the seat occupant. Movement of the seat relative to the vehicle in response to sudden movement of the vehicle caused by an explosion or hard landing causes the tensioning belt to automatically pretension the seat harness. The various embodiments described herein can include devices, components or features that are at least generally similar to those described in U.S. Pat. No. 8,469,401, entitled “SEAT HARNESS PRETENSIONER,” filed May 17, 2011; U.S. Pat. No. 8,649,400, entitled “SEAT HARNESS PRETENSIONER,” filed Feb. 23, 2010; and U.S. Patent Application No. 61/154,731, entitled “SEAT HARNESS PRETENSIONER,” filed Feb. 23, 2009; all of which are incorporated herein by reference in their entireties.

Certain details are set forth in the following description and inFIGS. 1-7Bto provide a thorough understanding of various embodiments of the disclosure. Other details describing well-known structures and systems often associated with vehicle seats, seat stroking devices, web retractors, seat harnesses, and other personal restraint devices. have not been set forth in the following disclosure to avoid unnecessarily obscuring the description of the various embodiments of the present disclosure.

Many of the details, dimensions, angles, and other features shown in the Figures are merely illustrative of particular embodiments of the disclosure. Accordingly, other embodiments can add other details, dimensions, angles, and features without departing from the spirit or scope of the present disclosure. In addition, those of ordinary skill in the art will appreciate that further embodiments of the invention can be practiced without several of the details described below. In the Figures, identical reference numbers identify identical, or at least generally similar, elements.

FIG. 1is an isometric view of a seat110having a restraint system pretensioner assembly100configured in accordance with an embodiment of the present disclosure. The seat110is mounted in a vehicle10and is movable vertically in response to a sudden impact, explosion, or other sudden acceleration or deceleration (in a vertical direction). The seat110can include a stroking device or stroking mechanism112which may be provided in any form that moves or allows the seat110to move vertically downward relative to the vehicle10in the direction of arrow A during a detonation, explosion, or other event that suddenly accelerates the vehicle10upwardly. As used herein, downward means generally in the direction of gravity. With the vehicle in a normal upright position, for example, downward is shown by the arrow A inFIG. 1.

As discussed above, stroking devices generally allow a seat to move downwardly during an impact. In some embodiments, however, stroking devices such as the stroking mechanism112can be configured to permit the seat110to be movable in other directions, such as fore and aft, side to side, or any combination thereof. The stroking mechanism112accordingly may be attached to the back, the bottom, or even the sides of the seat110. In addition, some blast resistant seats configured in accordance with embodiments of the present disclosure can be suspended within the vehicle10. The pretensioners shown in the drawings and described herein may be used with virtually any such type of blast resistant seat.

The pretensioner assembly100can include a loading mechanism114and locking retractors116(identified individually as a first locking retractor116aand a second locking retractor116b), all of which can be mounted to the seat110. Although referred to herein as the locking retractors116, as further described below, the locking retractors116can provide for pretensioning and/or locking. The assembly100can also include a restraint harness117having shoulder straps118. The restraint harness117can be mounted to the seat110and operably coupled to the retractors116. The harness117extends upward from the retractors116and the shoulder straps118pass over a top of the seat110. In several embodiments, the shoulder straps118can be integrated with other portions of the harness117. For example, in some embodiments, the shoulder straps118can be coupled to a lap belt portion119of the harness117.

The assembly100can also include pretensioning cable assemblies120and locking cable assemblies122that can operably couple the loading mechanism114to the retractors116. The pretensioning cable assemblies120and the locking cable assemblies122can be constructed in a variety of suitable manners to transmit motion from the loading mechanism114to the retractors116. In the illustrated embodiment, for example, the pretensioning cable assemblies120and the locking cable assemblies122are Bowden cable assemblies that each include an outer cable guide or housing and an internal cable. The loading mechanism114includes a pivotable arm124having a first end portion126and a second end portion128. The arm124rotates about a pivot134having an axis B that is generally parallel with a base of the seat110and perpendicular to the stroking motion of the seat110. The first end portion126is positioned to contact a fixed portion130of the vehicle10, and the second end portion128is coupled to a pulley132that is in operable engagement with the pretensioning cable assemblies120. The fixed portion130does not move relative to the vehicle10when the seat110moves up and down via the stroking mechanism112.

As described in greater detail below, when the seat110moves downward relative to the vehicle10, the fixed portion130urges the first end portion126to pivot upwardly, and the second end portion128moves downwardly with the pulley132. The downward motion of the pulley132pulls on the pretensioning cable assemblies120causing retraction of the shoulder straps118into the retractors116. The downward motion of the second end portion128transmits a pushing force on the locking cable assemblies122, locking the retractors116and preventing outward extension of the shoulder straps118.

FIG. 2Ais a partially schematic side view of the seat110and the pretensioner assembly100in a neutral position and configured in accordance with an embodiment of the present disclosure.FIG. 2Bis another partially schematic side view illustrating the seat110and the pretensioner assembly100in a deployed position in accordance with an embodiment of the present disclosure. Referring toFIGS. 1, 2A and 2Btogether, when the seat110moves relative to the vehicle10in the direction of arrow A, the fixed portion130of the vehicle10moves upward relative to the seat110as shown by the arrow C. This upward relative movement causes the fixed portion130to contact the first end portion126of the arm124and the arm124rotates about the pivot134as shown by arrow D. When the arm124rotates, the second end portion128moves the attached pulley132downwardly.

FIG. 3Ais a front view of the loading mechanism114configured in accordance with an embodiment of the present disclosure. In the illustrated embodiment, the pulley132includes grooves302to engage and guide the internal cables of the pretensioning cable assemblies120.FIGS. 3B and 3Care cross-sectional side views along the lines3B-3B and3C-3C, respectively, ofFIG. 3A, and illustrating several components of the loading mechanism114configured in accordance with an embodiment of the present disclosure. In the illustrated embodiment, a rocker arm304is operably engaged with the pivotable arm124. As shown inFIG. 3C, movement of the second end portion128of the pivotable arm124downward causes the rocker arm304to rotate above a pivot point305, urging a distal end portion307of the rocker arm304upward to push on the inner cables of the locking cable assemblies122. Movement of the locking cable assemblies122can engage components of the retractors116to lock the retractors116and prevent outward motion or payout of the shoulder straps118.

FIG. 4is an exploded isometric view of the locking retractor116configured in accordance with an embodiment of the present disclosure. In the illustrated embodiment, the locking retractor116includes a spool406that is attached to a shaft408that extends through the retractor116. The shaft408and spool406can rotate about an axis E to pay out or retrieve the shoulder straps118. In particular, clockwise rotation about the axis E in the direction of arrow F pays out the shoulder straps118, while counter-clockwise rotation about the axis E in the direction of arrow G retracts the shoulder straps118. The retractor116can include a pretensioning portion402and a locking portion404. The locking portion404can include components (e.g., gears, pawls, springs, etc.) that operate to lock the retractor116in response to motion (e.g., pushing motion) of the locking cable assembly122. In several embodiments, the retractor components that operate to lock the retractor116in response to motion of the locking cable assembly122can be conventional components arranged in a conventional manner well known to those of skill in the art.

The pretensioning portion402can include a hub410that can be rotatably positioned on the shaft408. A plurality of ratchets414having pins416are positioned at least partially within the hub410and can releasably engage with teeth413of a gear412on the shaft408, as described in more detail below. The pretensioning cable assemblies120(FIG. 1) can include an internal pretensioning cable424, a portion of which wraps around the hub410. The shaft408extends through a locking plate418having a tab420. A portion of the internal cable424can extend downward through a cable opening426in the tab420and into the external guide of the pretensioning cable assembly120(FIG. 1). In response to downward motion of the pulley132(FIG. 1), a portion of the internal cable424is pulled downward through the cable opening426, unwinding at least a portion of the internal cable424from the hub410, and thereby rotating the hub410and the associated ratchets414about the axis E in the direction of arrow G. The rotation of the ratchets414around the shaft408in the direction of arrow G causes the ratchets414to engage with the shaft408, resulting in corresponding rotation of the shaft408in the direction of arrow G to retract the shoulder straps118, as described in more detail below. A cover422can be positioned to at least partially enclose several of the components of the pretensioning portion402.

FIG. 5is an isometric view of the hub410and a ratchet414configured in accordance with an embodiment of the present disclosure. In the illustrated embodiment, the hub410includes a plurality of ratchet pockets502. The ratchet pockets502are positioned around a shaft opening506and can rotatably receive the ratchets414. The hub410can be positioned on the shaft408with the gear412aligned with the ratchet pockets502. Each of the ratchets414can include one or more features that engage the gear teeth413. For example, in the illustrated embodiment, each of the ratchets414can include at least one ratchet tooth504that engages the gear teeth413. Additionally, each of the ratchets414can include detents (e.g., two detents508) that can assist in the rotational positioning of the ratchets within the ratchet pockets502, as described in more detail below.

FIG. 6is an isometric view of the locking plate418configured in accordance with an embodiment of the present disclosure. In the illustrated embodiment, the locking plate418includes an aperture or opening602. The shaft408can extend centrally through the opening602, creating an annular gap or track606between the shaft408and the sidewall or sidewalls of the opening602. The sidewall or sidewalls can define the opening602which can include a plurality of notches or recesses604positioned along the circumference of the opening602. The recesses604can have a sloping portion608and a catch portion610. When the hub410is positioned on the shaft408with the ratchets414positioned within the ratchet pockets502, the pins416of the ratchets414extend at least generally parallel to the axis E (FIG. 4) and into either the recesses604, or into the track606.

FIG. 7Ais a side view of several components of the retractor116configured in accordance with an embodiment of the present disclosure. In the illustrated embodiment, the ratchets414are positioned around the shaft408and within the ratchet pockets502(not shown inFIG. 7Afor clarity). During normal operation of the vehicle10(e.g., with the seat positioned as shown inFIG. 2A), the ratchets414are generally positioned as shown inFIG. 7A, with the pins416extending into the recesses604, and the ratchet teeth504disengaged from the gear teeth413. Each of the ratchet pockets502includes a corresponding set screw702(e.g., a spring loaded set screw or a ball-nosed spring plunger) that engages with the detents508of the corresponding ratchet414. The set screws702can at least partially maintain the rotational position of the corresponding ratchets414within the associated ratchet pockets502. With the components positioned as shown inFIG. 7A, the shaft408and the spool406(FIG. 4) are free to rotate in the direction of arrow F to pay out the shoulder straps118.

FIG. 7Bis a side view of several components of the retractor116configured in accordance with an embodiment of the present disclosure. Referring toFIGS. 2B, 4, 5, 7A and 7Btogether, when the vehicle10experiences an event that results in the seat110moving to the position shown inFIG. 2B(e.g., an explosion that accelerates the vehicle10in a vertical direction), downward motion of the internal cable424through the cable opening426rotates the hub410and the ratchets414around the shaft408in the direction of arrow G. As the ratchets414move in the direction of arrow G from the position shown inFIG. 7A, the associated pins416are brought into contact with the sloping portions608, forcing the pins416into the track606and rotating the ratchets414within the associated ratchet pockets502. The rotation of the ratchets414within the ratchet pockets502brings the ratchet teeth504into contact with the gear teeth413, “locking” the hub410to the shaft408. The tolerance between the pins416and the track606can help to maintain the rotational position of the ratchets414within the ratchet pockets502, such that the teeth504maintain engagement with the gear teeth413. As the hub410is further rotated in the direction of arrow G by the downward motion of the internal cable424, the pins416travel along the track606, and the ratchet teeth504drive the gear teeth413, thereby rotating the shaft408and the attached spool406in the direction of arrow G. The rotation of the spool406in the direction of arrow G retracts the shoulder straps118and pretensions the restraint harness117.

In some embodiments configured in accordance with the present technology, the pretensioner assembly100can be reset to allow for pretensioning in a second event that follows a first or initial pretensioning event. For example, after a first event that pretensions the restraint harness117, and when the retractor116is no longer locked via the locking cable assemblies122, the shoulder straps118can be paid out via rotation of the shaft408in the direction of arrow F. In particular, when the ratchet teeth504are engaged with the gear teeth413(as shown inFIG. 7B), rotation of the shaft408in the direction of arrow F can push the gear teeth413against the ratchet teeth504. The exertion of the gear teeth413includes a component of force that pushes the ratchets504outwardly, pushing the pins416against the sidewalls of the opening602. While the pins416are in between the recesses604, the pins416are maintained in the track606by the sidewalls of the opening602. When the pins advance to a position adjacent to the recesses604, the pins416move outwardly and are caught by the catch portions610. The catch portions610engage the pins416(as shown inFIG. 7A), rotating the ratchets414within the ratchet pockets502(FIG. 5) to disengage the teeth504from the gear412. These and/or other steps may be performed to prepare the pretensioner assembly100and the seat110for a subsequent or second pretensioning event.

Although the components and features of the embodiments illustrated inFIGS. 1-7Bare shown in various arrangements and positions, other configurations of the components and features of the present technology are within the scope of the disclosure. For example, although particular embodiments described herein include three ratchets arranged around a shaft, alternative embodiments may include more or fewer ratchets. Similarly, the shapes and sizes of the ratchets, the ratchet pockets, and/or other components can be altered and still fall within the scope of the present disclosure. Additionally, the positioning of components described with respect to particular embodiments herein may be altered in alternative embodiments. For example, locking retractors in accordance with the present technology may have gears that are positioned internal to a shaft. Moreover, the gears may be integral with a shaft, or they may be operably coupled to a shaft. While the pretensioner assemblies described herein include ratchets, hubs, and various other components, pretensioner assemblies in accordance with the present technology can include additional and/or fewer components arranged in a variety of suitable configurations.

From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the various embodiments of the invention. Additionally, aspects of the invention described in the context of particular embodiments may be combined or eliminated in other embodiments. Furthermore, while various advantages associated with certain embodiments of the invention have been described above in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited, except as by the appended claims.