DEVICE FOR CONSTRAINING ACTUATOR MOTION DURING A DYNAMIC EVENT

Abstract

A device for constraining rotational motion of an actuator such as a seat actuator during a dynamic event. The device includes a first part attachable to a fixed frame member and carrying a first clip, and a second part attachable to an actuator and carrying a second clip. Prior to and following a dynamic event sufficient to cause actuator rotational motion the first clip and the second clip are disengaged. During the dynamic event the second clip is configured to engage the first clip to momentarily stop rotational motion of the actuator such that load on the actuator passes through the actuator shaft into the frame. In embodiments, the device is configured to minimize actuator deformation during a dynamic event while allowing a full range of standard motion during normal use of the actuator.

Claims

1. A device for constraining rotational motion of an actuator during a dynamic event, comprising: a first part attachable to a frame member, the first part carrying a first clip; and a second part attachable to an actuator proximate one end of the actuator, the second part carrying a second clip; wherein, prior to a dynamic event sufficient to cause actuator rotational motion, the first clip and the second clip are disengaged; and wherein, during the dynamic event sufficient to cause actuator rotational motion, the second clip is configured to engage the first clip to momentarily stop rotational motion of the actuator.

2. The device according to claim 1, wherein the first part includes an opening configured to receive a transverse frame member therethrough and a mechanical stop configured to limit rotational motion of the actuator in a forward direction.

3. The device according to claim 1, wherein: the first clip includes a first hook extending in a first direction; the second clip includes a second hook extending in a second direction opposite the first direction; and the first and second hooks are configured to pass each other during the dynamic event sufficient to cause actuator rotational motion.

4. The device according to claim 3, wherein the second part includes an annular collar configured to be received around a shaft of the actuator, and the second hook is formed on a radial extension of the annular collar.

5. The device according to claim 1, wherein the dynamic event sufficient to cause actuator rotational motion is at least a 12 g-force event.

6. A passenger seat, comprising: a seat pan; a seat back rotationally coupled to the seat pan; an actuator coupled at a first end to the seat pan and at a second end to the seat back, the actuator operable to control rotational motion of the seat back relative to the seat pan, and the actuator including a shaft; and a device configured to constrain rotational motion of the actuator during a dynamic event, the device comprising: a first part attached to the seat pan, the first part carrying a first clip; and a second part attached to the actuator proximate the first end, the second part carrying a second clip; wherein, prior to a dynamic event sufficient to cause actuator rotational motion, the first clip and the second clip are disengaged; and wherein, during a dynamic event sufficient to cause actuator rotational motion, the second clip is configured to engage the first clip to momentarily stop rotational motion of the actuator.

7. The passenger seat according to claim 6, wherein the first part includes an opening receiving a transverse frame member of the seat pan therethrough, and a mechanical stop configured to limit rotational motion of the actuator in a forward direction relative to the seat pan.

8. The passenger seat according to claim 6, wherein: the first clip includes a first hook extending in a first direction; the second clip includes a second hook extending in a second direction opposite the first direction; and the first and second hooks are configured to pass each other as the actuator rotates in a forward direction of the seat pan during the dynamic event sufficient to cause actuator rotational motion.

9. The passenger seat according to claim 8, wherein the second part includes an annular collar configured to be received around a shaft of the actuator, and the second hook is formed on a radial extension of the annular collar.

10. The passenger seat according to claim 6, wherein the dynamic event sufficient to cause actuator rotational motion is at least a 12 g-force event.

11. The passenger seat according to claim 6, wherein the actuator is a linear actuator including a stepper motor and a lead screw, and wherein the second clip surrounds a portion of the lead screw.

12. A passenger seat, comprising: a seat pan including a transverse frame member; a seat back rotationally coupled to the seat pan; an actuator coupled at a first end to the seat pan and at a second end to the seat back, the actuator operable to control rotational motion of the seat back relative to the seat pan, and the actuator including a shaft; and a device configured to constrain rotational motion of the seat back during a dynamic event, the device comprising: a brace pivotally attached at one end to the seat back and including a free end having a profile matching a profile of the transverse frame member; and a biasing member configured to bias the free end of the brace toward the transverse frame member; wherein, prior to a dynamic event sufficient to cause actuator rotational motion, the free end of the brace is disengaged from the transverse frame member; and wherein, during a dynamic event sufficient to cause actuator rotational motion, the free end of the brace is configured to move into engagement with the transverse frame member to stop rotational motion of the seat back in a rearward direction relative to the seat pan.

13. The passenger seat according to claim 12, wherein, during the dynamic event sufficient to cause rotational motion of the actuator, the seat back is configured to rotate forward relative to the seat pan thereby causing the link to follow along an outer surface of the transverse frame member until the free end is clear to engage the outer surface of the transverse frame member.

14. The passenger seat according to claim 12, wherein each of the transverse frame member and the free end of the brace has a rectangular cross-section.

15. The passenger seat according to claim 12, wherein the dynamic event sufficient to cause actuator rotational motion is at least a 12 g-force event.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The detailed description is described with reference to the accompanying FIGURES. The use of the same reference numbers in different instances in the description and the FIGURES may indicate similar or identical items. Various embodiments or examples (examples) of the disclosure are disclosed in the following detailed description and the accompanying drawings. The drawings are not necessarily to scale. In general, operations of disclosed processes may be performed in an arbitrary order, unless otherwise provided in the claims. In the drawings:

[0023] FIG. 1A illustrates a perspective view of a prior art seat frame including an actuator configured to drive seat back recline;

[0024] FIG. 1B illustrates a perspective view of the prior art seat frame of FIG. 1 following dynamic event testing;

[0025] FIGS. 2A-2D illustrate sequential side views of the motion of an actuator constrained with a device in accordance with an embodiment of this disclosure;

[0026] FIGS. 3A-3C illustrate sequential side views of the action of the device shown in FIGS. 2A-2D; and

[0027] FIGS. 4A-4D illustrate sequential perspective views of the motion of a device for constraining an actuator in accordance with another embodiment of this disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0028] Reference will now be made in detail to the subject matter disclosed, which is illustrated in the accompanying drawings.

[0029] Before explaining one or more embodiments of the disclosure in detail, it is to be understood that the embodiments are not limited in their application to the details of construction and the arrangement of the components or steps or methodologies set forth in the following description or illustrated in the drawings. In the following detailed description of embodiments, numerous specific details may be set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art having the benefit of the instant disclosure that the embodiments disclosed herein may be practiced without some of these specific details. In other instances, well-known features may not be described in detail to avoid unnecessarily complicating the instant disclosure.

[0030] As used herein a letter following a reference numeral is intended to reference an embodiment of the feature or element that may be similar, but not necessarily identical, to a previously described element or feature bearing the same reference numeral (e.g., 1, 1a, 1b). Such shorthand notations are used for purposes of convenience only and should not be construed to limit the disclosure in any way unless expressly stated to the contrary.

[0031] Further, unless expressly stated to the contrary, or refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0032] In addition, use of a or an may be employed to describe elements and components of embodiments disclosed herein. This is done merely for convenience and a and an are intended to include one or at least one, and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0033] Finally, as used herein any reference to one embodiment or some embodiments means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment disclosed herein. The appearances of the phrase in some embodiments in various places in the specification are not necessarily all referring to the same embodiment, and embodiments may include one or more of the features expressly described or inherently present herein, or any combination of sub-combination of two or more such features, along with any other features which may not necessarily be expressly described or inherently present in the instant disclosure.

[0034] Broadly, the present disclosure provides embodiments of devices for controlling motion of an actuator during a dynamic event such as a high g-force event causing abnormal seat frame motion. During normal use of the seat, the devices allow standard range of motion of the seat, for instance seat back adjustment between an upright sitting position and a reclined sitting position or horizontal bed. During a dynamic event exceeding a predetermined threshold g-force, for instance a 12G or 16G event, movement of seat back forward of TTOL carries with it the coupled actuator causing rotational motion of the actuator. The initial rotational motion, for instance in the forward direction of the seat, readies the devices for action. During rebound of the seat back, for instance in the rearward direction of the seat, the readied devices briefly engage to momentarily stop rotational motion of the actuator such that a majority of load on the actuator is able to pass through the actuator shaft and into the seat frame. After the momentary stoppage of the rotational motion, the devices may or may not remain engaged. As discussed further below, device engagement constrains the actuator such that plastic deformation of the actuator is controlled and/or minimized during a dynamic event.

[0035] While device embodiments according to the present disclosure are described with application to an aircraft passenger seat, and particularly utilized in the coupling between the seat pan and the seat back, it is intended and envisioned that the device principles can be applied to other motion control systems wherein a component is subject to loads sufficient to cause unwanted plastic deformation.

[0036] FIGS. 2A-D illustrate a motion control device according to an embodiment of the present disclosure. The motion control device 200 is configured to be installed on a passenger seat having a seat back rotationally coupled to a seat pan, such as the seat frame shown in FIGS. 1A-1B. The seat is equipped with an actuator 202 coupled at one end to a frame member 204 located in the seat pan, and at an opposing end to a frame member 206 located in the seat back. The actuator 202 shown is a linear actuator generally including a stepper motor 208 and a shaft 210 in the form of a lead screw. In use, the stepper motor 208 is energized to drive rotation of the lead screw. For example, elongating the actuator 202 causes seat back rotation in the forward direction of the seat corresponding to seat back incline, whereas shortening the actuator 202 causes seat back rotation in the rearward direction of the seat corresponding to seat back recline.

[0037] The motion control device 200 generally includes a first part 212 attachable to a frame member located in the seat pan and a second part 214 attachable to the actuator shaft 210. In some embodiments, the first part 212 is attached to the transverse frame member 204 such as the tubular frame member shown. In embodiments, the first part 212 may be implemented as at least one plate 216 defining an attachment location for the first end of the actuator. The at least one plate 216 may further define an opening receiving the transverse frame member 204 therethrough. In embodiments, the at least one plate 216 may further include a mechanical stop 218 for stopping travel of the first end of the actuator shaft 210 in the forward direction of the seat. The first part 212 further includes a first clip 220 configured to interact with a second clip of the second part as discussed further below.

[0038] The second part 214 is coupled to the actuator 202 proximate the first end of the actuator. In some embodiments, the second part 214 includes an annular collar 222 positioned around the actuator shaft 210. A portion of the annular collar 222 extends radially outward toward the first part 212. The extension carries or forms a second clip 224 configured to interact with the first clip 220 as discussed further below.

[0039] FIGS. 2A and 3A show the motion control device 200 during normal use of the seat (i.e., prior to a dynamic event). During normal use, the first part 212 and the second part 214 are disengaged and do not interact. In embodiments, the first clip 220 includes a first hook 226 and the second clip 224 includes a second hook 228. The first and second hooks 226, 228 face each other and are ramped such that the hooks are able to pass one another to ready the motion control device 200 for engagement as discussed further below. In embodiments, the first clip 220 bends around the transverse frame member 204 for support.

[0040] FIG. 2B shows the motion control device 200 readied for engagement. As the seat back rotates forward past the TTOL position in response to a dynamic event of sufficient magnitude threshold, the actuator 202 rotates forward carrying the second part 214 thereby causing the second hook 228 to move past the first hook 226. The actuator rotates forward until the shaft 210 engages the mechanical stop 218. The mechanical stop 218 prevents at least the first end of the shaft 210 from rotating further forward past a predetermined angle. In some embodiments, the seat back and second end of the actuator may continue to rotate forward past the mechanical stop 218 thereby causing the shaft 210 to bend about the mechanical stop. In embodiments, the event threshold is an event sufficient to cause component deformation, for instance actuator shaft deformation. In embodiments, the event threshold may be a 2 g-force event, 3 g-force event, 4 g-force event, 5 g-force event . . . n g-force event.

[0041] FIGS. 2C and 3B show engagement of the first and second hooks 226, 228 as the seat back rebounds following a transition from rotation in the forward direction to rotation in the rearward direction. The actuator 202 rotates in the rearward direction until the first and second hooks 226, 228 engage. Engagement of the first and second hooks 226, 228 momentarily stops rotation of the actuator 202 in the rearward direction long enough that a majority of load on the actuator 202 passes through the actuator shaft 210 and in the seat frame. In some embodiments, the momentary rotational stop causes the actuator shaft 210 to bend slightly toward a forward direction of the seat (i.e., opposite the bending direction shown in FIG. 1B.

[0042] FIGS. 2D and 3C show the disengagement of the first and second hooks 226, 228 after the dynamic event. The first and second hooks 226, 228 interact when the actuator shaft 210 rotates rearward to a certain point but permit the actuator shaft 210 to rotate forward. As the seat back ultimately comes to rest, the first and second hooks 226, 228 may engage to prevent further seat back rotation should the seat frame fail as a result of the dynamic event. In some embodiments, the engagement position of the first and second hooks 226, 228 can be customized to determine the seat back angle following a dynamic event, considering the plastic deformation of the actuator shaft 210. In embodiments, the engagement position of the first and second clips 212, 214, length and/or angle of the mechanical stop 218, and combinations thereof may be customized to control bending in the actuator shaft 210 during a dynamic event.

[0043] FIGS. 4A and 4B illustrate a motion control device according to another embodiment of the present disclosure. The motion control device 400 generally includes a brace 402 rotatably coupled at one end to a frame member such as a seat back frame member 404. A detached end of the brace shown generally at 406 defines a profile matching a profile of another seat frame member, for instance a seat pan frame member 408. As shown, in a non-limiting example, the seat pan frame member 408 is tubular and has a square cross section and the detached end 406 of the brace 402 has a matching square profile. A biasing member 410, for instance a tension spring, is configured to bias the detached end 406 toward the seat pan frame member 408 such that rotational movement of the seat back causes the brace 402 to drag along the seat pan frame member 408 without losing contact.

[0044] FIG. 4A shows the brace 402 during normal use of the seat (e.g., seat movement between TTOL and reclined). As shown, the free end 406 is disengaged from the seat pan frame member 408. As shown in FIG. 4B, as the seat back rotates forward past the TTOL position as the result of a dynamic event, the brace 402 drags along the outer surface of the seat pan frame member 408. As shown in FIG. 4C, as the seat back continues to rotate forward past TTOL the detached end 406 nears a transition point from detached to engaged. As shown in FIG. 4D, sufficient rotational movement of the seat frame forward of TTOL clears the detached end 406 such that the detached end can move to engage the seat pan frame member 408. When braced, the seat back is prevented from rebounding past a certain angle thereby allowing a majority of the load to pass through the brace 402 and the actuator 202 to the seat frame.

[0045] Although the disclosure has been described with reference to the embodiments illustrated in the attached drawing FIGURES, equivalents may be employed and substitutions made herein without departing from the scope of the claims. Components illustrated and described herein are merely examples of a system/device and components that may be used to implement embodiments of the disclosure and may be replaced with other devices and components without departing from the scope of the claims. Furthermore, any dimensions, degrees, and/or numerical ranges provided herein are to be understood as non-limiting examples unless otherwise specified in the claims.