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. An actuator assembly, comprising: a linear actuator comprising a shaft, the linear actuator having a first end configured to be attached to a seat pan frame member and a second end configured to be attached to a seat back frame member rotatable relative to the seat pan frame member using the linear actuator; and a motion control device for controlling plastic deformation of the shaft during a dynamic event exceeding a predetermined threshold, the motion control device comprising: a first part configured to be attached to the seat pan frame member, the first part comprising a mechanical stop and a first clip; and a second part mounted on the shaft proximal to the first end of the actuator, the second part comprising a second clip; wherein, during the dynamic event exceeding the predetermined threshold, the mechanical stop is configured to constrain rotational motion of the shaft in a first direction and the first and second clips are configured to engage to momentarily constrain rotational motion of the shaft in a second direction opposite the first direction.

2. The actuator assembly of claim 1, wherein the first part is implemented as a plate having an opening for receiving the seat pan frame member, and the second part is implemented as a collar mounted on the shaft.

3. The actuator assembly of claim 1, wherein, during use of the motion control device, rotational motion of the shaft in the first direction readies the first and second clips for momentarily constraining rotational motion of the shaft in the second direction.

4. The actuator assembly of claim 1, wherein: the first clip comprises a first hook; the second clip comprises a second hook; rotational motion of the shaft in the first direction causes the second hook to pass over the first hook; and rotational motion of the shaft in the second direction causes the second hook to engage the first hook to momentarily constrain rotational motion of the shaft in the second direction.

5. The actuator assembly of claim 4, wherein the first hook extends toward the shaft and the second hook extends toward the first hook, and wherein the first and second hooks are ramped in opposite directions such that the first and second hooks are configured to pass one another to ready the motion control device for engagement to momentarily constrain rotation of the shaft in the second direction.

6. The actuator assembly of claim 1, wherein the first clip defines a bend for bending around the seat pan frame member.

7. The actuator assembly of claim 1, wherein the first direction corresponds to forward motion of the seat back frame member and the second direction corresponds to rearward motion of the seat back frame member.

8. A passenger seat assembly, comprising: a seat pan including a seat pan frame member; a seat back including a seat back frame member; a linear actuator comprising a shaft, the linear actuator having a first end attached to the seat pan frame member and a second end attached to the seat back frame member, wherein the seat back is rotatable relative to the seat pan using the linear actuator; and a motion control device for controlling plastic deformation of the shaft during a dynamic event exceeding a predetermined threshold, the motion control device comprising: a first part attached to the seat pan frame member, the first part comprising a mechanical stop and a first clip; and a second part mounted on the shaft proximal to the first end of the actuator, the second part comprising a second clip; wherein, during the dynamic event exceeding the predetermined threshold, the mechanical stop is configured to constrain rotational motion of the shaft in a first direction and the first and second clips are configured to engage to momentarily constrain rotational motion of the shaft in a second direction opposite the first direction.

9. The passenger seat assembly of claim 8, wherein the first part is implemented as a plate having an opening receiving the seat pan frame member, and the second part is implemented as a collar mounted on the shaft.

10. The passenger seat assembly of claim 8, wherein, during use of the motion control device, rotational motion of the shaft in the first direction readies the first and second clips for momentarily constraining rotational motion of the shaft in the second direction.

11. The passenger seat assembly of claim 8, wherein: the first clip comprises a first hook; the second clip comprises a second hook; rotational motion of the shaft in the first direction causes the second hook to pass over the first hook; and rotational motion of the shaft in the second direction causes the second hook to engage the first hook to momentarily constrain rotational motion of the shaft in the second direction.

12. The passenger seat assembly of claim 11, wherein the first hook extends toward the shaft and the second hook extends toward the first hook, and wherein the first and second hooks are ramped in opposite directions such that the first and second hooks are configured to pass one another to ready the motion control device for engagement to momentarily constrain rotation of the shaft in the second direction.

13. The passenger seat assembly of claim 8, wherein the first clip bends around the seat pan frame member.

14. The passenger seat assembly of claim 8, wherein the first direction corresponds to forward motion of the seat back relative to the seat pan, and the second direction corresponds to rearward motion of the seat back relative to the seat pan.

15. A motion control device for controlling plastic deformation of an actuator shaft during a dynamic event exceeding a predetermined threshold, the motion control device comprising: a first part attachable to a seat pan, the first part comprising a mechanical stop and a first clip; and a second part mountable on the actuator shaft, the second part comprising a second clip; wherein, during the dynamic event exceeding the predetermined threshold, the mechanical stop is configured to constrain rotational motion of the actuator shaft in a first direction, rotational motion of the actuator shaft in the first directions readies the first and second clips foe engagement, and the first and second clips engage to momentarily constrain rotational motion of the shaft in a second direction opposite the first direction.

16. The motion control device of claim 15, wherein the first part is implemented as a plate having an opening for receiving a seat pan frame member, and the second part is implemented as a collar mountable around the actuator shaft.

17. The motion control device of claim 15, wherein: the first clip comprises a first hook; the second clip comprises a second hook; rotational motion of the actuator shaft in the first direction causes the second hook to pass over the first hook; and rotational motion of the actuator shaft in the second direction causes the second hook to engage the first hook to momentarily constrain rotational motion of the actuator shaft in the second direction.

18. The motion control device of claim 15, wherein the first and second hooks are ramped in opposite directions such that the first and second hooks are configured to pass one another to ready the motion control device for engagement to momentarily constrain rotation of the actuator shaft in the second direction.

19. The motion control device of claim 17, wherein rotation of the actuator shaft in the first direction causes the second hook to move past the first hook and the actuator shaft to engage the mechanical stop to prevent one end of the actuator shaft from rotating further in the first direction past a predetermined angle.

20. The motion control device of claim 17, wherein the second part is implemented as an annular collar and the second hook is formed on a radial extension of the annular collar.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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:

[0024] FIG. 1A illustrates a perspective view of a prior art seat frame including an actuator configured to drive seat back recline;

[0025] FIG. 1B illustrates a perspective view of the prior art seat frame of FIG. 1 following dynamic event testing;

[0026] 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;

[0027] FIGS. 3A-3C illustrate sequential side views of the action of the device shown in FIGS. 2A-2D; and

[0028] 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

[0029] Reference will now be made in detail to the subject matter disclosed, which is illustrated in the accompanying drawings.

[0030] 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.

[0031] 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.

[0032] 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).

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.