Seat assembly having an adjustable head restraint assembly

A seat assembly having a headrest disposed on a support post. The headrest has a front shell and a rear shell. The front shell and rear shell may be configured to move in unison such that the front shell moves a greater distance than the rear shell.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a seat assembly having an adjustable head restraint assembly.

SUMMARY OF THE INVENTION

In at least one embodiment, a seat assembly is provided. The seat assembly may include a headrest disposed on the support post. The headrest may have a front shell and a rear shell. The front shell and rear shell may be configured to move in unison such that the front shell moves a greater distance than the rear shell.

In at least one embodiment, a seat assembly is provided. The seat assembly may have a head restraint assembly that includes a support post and a headrest moveably disposed on the support post. The headrest may have a front shell and a rear shell that are configured to move with respect to each other. A traverse member may be disposed in the headrest and may have an opening through which the support post extends. The support frame may be moveably disposed on the traverse member. The support frame may have a guide arm disposed above the support post that is received by the front shell for guiding movement of the front shell.

In at least one embodiment, a seat assembly is provided. The seat assembly may have a support post and headrest moveably disposed on the support post. A traverse member may be disposed in the headrest. The traverse member may include a hub and a block disposed proximate the hub. A support linkage may be rotatably disposed on the hub. The support linkage may have a mounting groove that receives the block. The support post may extend through the hub and the block may help retain the support linkage on the hub when the block is disposed in the mounting groove.

DETAILED DESCRIPTION

Referring toFIG. 1, an exemplary seat assembly10is shown. The seat assembly10may be configured for use in a vehicle, such as a motor vehicle like a car or truck.

The seat assembly10may include a seat bottom12and a seat back14. The seat bottom12may be configured to be mounted on a support surface, such as a floor pan of a vehicle. The seat back14may be pivotally disposed on the seat bottom12and may include a head restraint assembly16.

Referring toFIGS. 2-4, the head restraint assembly16may include a headrest20and one or more support posts22. The headrest20may be moveably disposed on the support post22as will be described in more detail below. The support post22may be made of any suitable material or materials, such as a metal like an aluminum alloy.

The support post22may be configured to couple the headrest20to the seat back14. The support post22may include and upper portion24and one or more lower portions26. The upper and lower portions24,26may be integrally formed and may cooperate to form a support post22having a generally U-shaped configuration in which the upper portion24extends between and connects a pair of lower portions26as is best shown inFIG. 7. As such, the upper portion24may help strengthen or provide structural reinforcement for the support post22.

The lower portion26may have a linear or non-linear configuration. An exemplary non-linear configuration is shown inFIG. 4in which the lower portion26is bent at an angle. An end of the lower portion26, such as a region below the bend in the embodiment shown inFIG. 4, may extend through the top of the seat back14and may be fixedly mounted to a structural frame of the seat back14such that the support post22does not move with respect to the seat back14.

The support post22may include a plurality of notches28. The notches28, which are best shown inFIG. 12, may be spaced apart from each other and may provide predetermined positions at which the headrest20may be positioned along the support post22. In at least one embodiment, the notches28may be provided on a region of the support post22that is disposed inside the headrest20.

The headrest20may be configured to support the head of an occupant of the seat assembly10. The headrest20may include a front portion30and a rear portion32. The front portion30may be moveable with respect to the rear portion32as will be discussed in more detail below.

Referring toFIGS. 4-7, an exemplary front portion30is shown in more detail. The front portion30may be configured to engage or support the head of a seat occupant. The front portion30may include a trim cover40, a cushion42, and a front support shell44. The trim cover40and cushion42are not shown inFIG. 7for clarity.

The trim cover40may cover at least a portion of a visible exterior surface of the front portion30that may engage the head of a seat occupant. The trim cover40may be made of any suitable material or materials, such as a fabric, vinyl, leather, or the like. The trim cover40may be mounted on the front support shell44. For instance, the trim cover40may generally wrap around one or more sides of the front support shell44and may be coupled thereto to provide a desired aesthetic appearance.

The cushion42may be disposed under at least a portion of the trim cover40. As such, the cushion42may be disposed between trim cover40and the front support shell44such that a first surface of the cushion42may engage the trim cover40and a second surface disposed opposite the first surface may engage the front support shell44. The cushion42may be made of any suitable material, such as foam.

The front support shell44may provide structural support for the front portion30. The front support shell44may be made of any suitable material, such as a polymeric material that may be configured to flex. In at least one embodiment, the front support shell44may include a front side50, a back side52, a plurality of mounting features54, an upper guide opening56, and a lower guide opening58.

The front side50may face toward the head of a seat occupant and may engage the cushion42. The back side52may be disposed opposite the front side50and may face toward the rear portion32. As is best shown inFIG. 7, one or more mounting features54may be provided on the back side52that engage internal components of the head restraint assembly16as will be discussed in more detail below. The mounting features54may have a male configuration, a female configuration, or combinations thereof. In the embodiment shown, four mounting features54are provided that are configured as holes in the front support shell44. The mounting features54may be provided in pairs with each pair being positioned along an axis.

One or more upper guide openings56may be provided in the front support shell44to help guide movement of the front portion30with respect to the rear portion32as will be discussed in more detail below. In the embodiment shown, two upper guide openings56are provided near the top of the front support shell44that are spaced apart from each other. The upper guide openings56may extend from the back side52toward the front side50and may be arranged substantially parallel to each other in one or more embodiments.

One or more lower guide openings58may be disposed near the bottom of the front support shell44. The lower guide opening58may also help guide movement of the front portion30and may extend substantially parallel to the upper guide openings56. The lower guide opening58may include a slot60that may be disposed at the top of the lower guide opening58. The slot60may be configured to receive an engagement feature that extends through the slot60and into the lower guide opening58as will be discussed in more detail below.

The front portion30may also include an input device, such as a button64. The button64may extend at least partially through a hole in a side of the front portion30. A bezel66may be provided that extends at least partially around the button64to facilitate mounting and help provide a desired aesthetic appearance. The button64may be part of a latch subsystem that will be described in more detail below.

Referring toFIGS. 4-6and8-10, the rear portion32and internal components of the head restraint assembly16are shown in more detail. The rear portion32may include a rear shell70that may cover at least a portion of its visible exterior surface. The rear shell70may have a bowl-like configuration that may at least partially define an opening that faces toward the front portion30. Internal components that may be concealed by and/or disposed at least partially within the rear shell70may include a traverse member72, a support frame74, a pivot member76, a support linkage78, and a latch subsystem80.

Referring toFIG. 10, the traverse member72may be configured to move along the support post22. In at least one embodiment, the traverse member72may include a center portion90and one or more guide blocks92disposed at opposite ends of the center portion90. The traverse member72may be made of any suitable material, such as a polymeric material.

Referring toFIGS. 8-10, the center portion90may be generally disposed below the upper portion24of the support post22. The center portion90may include a latch mounting region100and a guide feature102.

The latch mounting region100may facilitate mounting of at least a portion of the latch subsystem80as will be described in more detail below. In the embodiment shown, the latch mounting region100is generally disposed on a top surface of the center portion90proximate the middle of the center portion90.

The guide feature102may help support and guide movement of the front portion30with respect to the traverse member72. The guide feature102may extend from a bottom surface of the center portion90. In the embodiment shown, the guide feature102is disposed directly below the latch mounting region100. The guide feature102may be received in the lower guide opening58and may be configured to permit the front portion30to move toward or away from the traverse member72while helping constrain movement in other directions. In at least one embodiment, the guide feature102may have an inverted T-shaped configuration where a first portion104of the guide feature102extends downwardly through the slot60and a second portion106extends outwardly from the first portion104. As such, the second portion106may engage a surface of the front support shell44that forms the lower guide opening58to permit the front support shell44to move in a fore-aft direction with respect to the traverse member72, or generally toward or away from the head of a seat occupant, while inhibiting movement in one or more other directions. In at least one embodiment, the second portion106may be disposed substantially perpendicular to the first portion104and may be disposed substantially parallel to the center portion90.

The guide blocks92may be integrally formed with the center portion90. Each guide block92may include a hole110that extends through the guide block92. One or more bushings112may be disposed in each hole110. In at least one embodiment, each hole110may be provided with two bushings112that may be coaxially disposed. One bushing112may be positioned above the other bushing112to help inhibit pivoting of the traverse member72with respect to the support post22. Each bushing112may have a bushing hole114for receiving the support post22. The bushings112may have the same or different configurations. Examples of bushings that may be used are disclosed in German patent application serial number 10 2010 031 048 and PCT international application number PCT/US2010/037725, which are assigned to the assignee of the present application and are hereby incorporated by reference in their entirety.

The guide blocks92may also include a guide slot120that may receive and help guide movement of the support frame74with respect to the traverse member72. The guide slot120may be provided on an exterior surface of the guide block92proximate the center portion90. In the embodiment shown, the guide slots120face toward each other and extend along the top of the center potion90in a substantially parallel relationship between front and back surfaces of the traverse member72. As such, the guide slot120may permit fore-aft movement of the support frame74with respect to the traverse member72while helping inhibit movement of the support frame74in one or more other directions.

The traverse member72may also include one or more vertical stops130and horizontal stops132that help limit the range of motion of the traverse member72with respect to the support post22. The vertical stop130may extend from a top surface134of the guide block92or center portion90toward the upper portion24of the support post22. Upward movement of the traverse member72may be inhibited when the vertical stop130engages the upper portion24. The horizontal stop132may extend from a rear surface136of the guide block92or traverse member72toward the support frame74. Forward movement of the support frame74may be inhibited with the horizontal stop132engages the support frame74and/or rear shell70. Vertical and/or horizontal stops130,132may be omitted in one or more embodiments. If provided, the vertical and horizontal stops130,132may be integrally formed with the traverse member72or provided as separate components that may be assembled to the traverse member72. By providing the vertical and/or horizontal stops130,132as separate components, a standardized traverse member configuration may be employed while providing the option of providing one or more stops to provide a desired range of motion to accommodate design parameters and/or regulatory requirements.

Referring toFIGS. 8 and 9, the support frame74may be moveably disposed on the traverse member72. The support frame74may be made of any suitable material, such as a metal like an aluminum alloy. The rear shell70may be fixedly mounted to the support frame74. The support frame74may have any suitable configuration. In the embodiment shown, the support frame74includes a top portion140, a back portion142, and one or more sets of mounting arms144.

The top portion140may be generally disposed at the top of the support frame74. The top portion140may generally extend from a top end of the back portion142toward the front support shell44. The top portion140may have one or more guide arms150and a bumper tab152.

The guide arms150may guide relative movement of the front and rear portions30,32and may help provide structural support for the headrest20. In at least one embodiment, a pair of guide arms150may be provided that are spaced apart from each other and that each may be received by an upper guide opening56on the front support shell44as is best shown inFIG. 7. In addition, the guide arms150may extend substantially parallel to each other.

The bumper tab152may extend toward the front portion30. In addition, the bumper tab152may be disposed between and may extend substantially parallel to the guide arms150in one or more embodiments. The bumper tab152may have a shorter length than the guide arms150such that it does not engage the front support shell44in one or more embodiments. A bumper154may be disposed on the bumper tab152for cushioning and/or limiting movement of headrest20along the support post22. For instance, the bumper154may be provided on a bottom surface of the bumper tab152that faces toward the upper portion24of the support post22to inhibit the upper portion24from engaging or contacting the guide arms150. In addition, the bumper154may be disposed above the upper portion24of the support post22throughout the range of fore-aft motion of the support frame74with respect to the traverse member72. The bumper154may be made of any suitable material, such as a polymeric material or elastomeric material like rubber.

The back portion142may be located between the rear shell70and the support post22. The bottom of the back portion142may be generally disposed rearward of the traverse member72in one or more embodiments. One or more openings may be provided in the back portion142to help reduce weight and/or material cost.

One or more sets of mounting arms144may be provided for moveably coupling the support frame74to the traverse member72. In the embodiment shown, two sets of mounting arms144are provided that extend from the back portion142toward the front portion30. Each set may include one or more arms, such as an upper arm160and a lower arm162. In such an embodiment, the upper and lower arms160,162may be spaced apart from each other and may extend substantially parallel to each other. The traverse member72may be disposed between the upper and lower arms160,162. As such, the upper and lower arms160,162may facilitate mounting of the support frame74by capturing the traverse member72between the upper and lower arms160,162. In addition or alternatively, the upper arm160, lower arm162, and/or traverse member72may include one or more fasteners that may help couple the support frame74to the traverse member72. Each upper arm160may be disposed in a corresponding guide slot120on the traverse member72and the latch mounting region100may be disposed between the upper arms160.

The upper and lower arms160,162may each have distal ends that include a slot164. The slots164in the upper and lower arms160,162may be similarly configured and may be aligned with each other. In addition, the slots164may have an elongated configuration such that the slots164may extend along a front edge of the upper and lower arms160,162and may be disposed substantially parallel to the upper portion24of the support post22. A bushing may be associated with one or more slots164to provide a bearing surface. The bushing may include an opening that has a similar configuration as an associated slot164.

Referring toFIGS. 12 and 13, one or more arms may include a set of teeth166. In the embodiment shown, the upper arms160each have a set of teeth166that extend along a side of each upper arm160that is disposed proximate the latch mounting region100of the traverse member72. The set of teeth166may cooperate with the latch subsystem80to allow the front portion30to be secured in predetermined discrete positions.

Referring toFIGS. 8,9and11, one or more pivot members76may be provided that facilitate angular movement of the front portion30. In the embodiment shown, two pivot members76are provided. The pivot members76may include one or more coupling features170that may engage the front portion30. The coupling features170may have a male configuration, female configuration, or combinations thereof. In at least one embodiment, the coupling features170may be configured as pins that are received in the mounting features54on the front support shell44. In addition, the pivot members76may include one or more mounting features, such as a first mounting feature172and a second mounting feature174. The first and second mounting features172,174may be spaced apart from each other and may each include a hole that may be coaxially disposed with each other. The holes may receive one or more fasteners, such as a pivot pin176.

The support linkage78may be provided to help support and/or control movement of an associated pivot member76. The support linkage78may include a first end having a first hole180and a second end disposed opposite the first end that has a second hole182.

The first hole180may be disposed on a hub184that may be provided on the traverse member72. The hub184may have an opening through which the support post22may extend. As such, the support linkage78may be configured to rotate about or with respect to the support post22. Moreover, the support linkage78may transmit force between the pivot member76and the traverse member72. The second end of the support linkage78may be disposed between the first and second mounting features172,174of the pivot member76and may be configured to facilitate rotation with respect to the pivot pin176.

The first end of the support linkage78may also include a mounting groove186. The mounting groove186may be disposed along a portion of an exterior circumference of the support linkage78and may have an arcuate configuration. The mounting groove186may be bounded by upper and lower walls190,192that may be spaced apart from each other and by first and second end walls194,196that may be disposed at opposite ends of the mounting groove186and may extend from or between the upper and lower walls190,192.

The upper wall190may include an opening198that may facilitate assembly of the support linkage78to the traverse member72. More specifically, the traverse member72may include a guide wall200that may extend partially around and may be spaced apart from the hub184. The guide wall200may have a curvature that generally follows that of the hub184. A block202may be disposed on the guide wall200and may extend toward and may be spaced apart from the hub184. In at least one embodiment, the block202may be integrally formed with the guide wall200and may be configured to fit within the mounting groove186.

The support linkage78may be installed on the hub184by aligning the block202with the opening198in the upper wall190. The support linkage78may then be moved axially onto the hub184such that the hub184is inserted into the first hole180and the block202is inserted through the opening198in the upper wall190. The support linkage78may then rotate about the hub184such that the block202may be disposed within the mounting groove186. The block202may cooperate with the walls of the mounting groove186to guide and control movement of the support linkage78. During normal operation, the block202may be rotated away from the opening198such that the block202may engage the upper and/or lower walls190,192, thereby inhibiting disengagement of the support linkage78from the hub184. In addition, the block202and upper and lower walls190,192may cooperate to transmit load forces. For instance, load forces imparted on the front portion30of the headrest20may be transmitted through pivot member76to the support linkage78, which then may be transmitted to the traverse member72by engagement of the block202with the upper wall190, lower wall192and/or the hub184, and between the support linkage78and the hub184.

The pivot pin176may couple the support frame74, pivot member76and support linkage78. For instance, the pivot pin176may extend through the slots164in the upper and lower arms160,162, holes in the first and second mounting features172,174, and the second holes182in the support linkage78. The slots164may help constrain and guide movement of the pivot pin176. For instance, the pivot pin176may slide within the slots164such that the pivot pin176is disposed near or at a first end of the slot164located near the center of the head restraint assembly16when in the retracted position as shown inFIG. 8. The pivot pin176may be disposed near a second end of the slot164that is disposed opposite the first end when in the extended position as shown inFIG. 9.

Referring toFIGS. 12-14, an embodiment of a latch subsystem80is shown. The latch subsystem80may be provided to help enable and disable movement of the head restraint assembly16. More specifically, the latch subsystem80may move between a latched position in which movement of the head restraint assembly16is disabled and an unlatched position in which movement of the head restraint assembly16in one or more directions is enabled. In at least one embodiment, the latch subsystem80includes one or more coupling members, such as a first coupling member210, a second coupling member212, and a third coupling member214. Alternatively, the latch subsystem80may be provided with a different mechanical linkage, such as one or more cables, or with an electrical or electromechanical actuator. For instance, an electrical machine, such as a motor or solenoid, may be provided that latches or actuates a latch to enable or disable movement of the head restraint assembly16.

The first coupling member210may be moveably disposed on a portion of the head restraint assembly16, such as the traverse member72. In addition, the first coupling member210may engage or be coupled to the button64. For example, the first coupling member210may be fastened to the button64and traverse member72in any suitable manner, such as with a fastener or snap fit into a slot in the button64. The first coupling member210may have any suitable configuration. For example, the first coupling member210may be provided as a wire that is formed in a generally rectangular shape in one or more embodiments. A biasing member216may bias the first coupling member210and the button64outward toward an initial position or generally away from a support post22toward an exterior surface of the headrest20. The biasing member216, which may be configured as a spring, may have a first end that engages the first coupling member210and a second end that engages the traverse member72.

The second coupling member212may be moveably associated with the first coupling member210. In addition, the second coupling member212may be adapted to permit or inhibit movement of the head restraint assembly16. For instance, the second coupling member212may include a support post engagement portion220that disables movement of the headrest20along the support post22when it engages a support post notch28and permits movement along the support post22when it does not engage a notch28. The support post engagement portion220may be disposed between a first end222and a second end224of the second coupling member212disposed opposite the first end222. The first end222may be configured to engage the first coupling member210. The second end224may be configured to engage the third coupling member214. As such, the second coupling member212may extend from the first coupling member210toward the latch mounting region100of the traverse member72. In at least one embodiment, the second end224may be disposed at an angle relative to an adjacent portion of the second coupling member212, such as at an angle that extends downward toward the traverse member72.

The second coupling member212may be disposed on the head restraint assembly16in any suitable manner. For example, a fastener226may be provided that couples the second coupling member212to the traverse member72. The fastener226may be provided as a clip and may permit the second coupling member212to slide along or within the fastener226. In addition, the second coupling member212may engage or may be received by part of the latch mounting region100to help guide its movement.

The third coupling member214may be moveably associated with the second coupling member212. In addition, the third coupling member214may be adapted to permit or inhibit movement of the head restraint assembly16. For instance, the third coupling member214may include one or more tooth engagement portions230that may disable movement of the front portion30when it engages a member of the set of teeth166as shown inFIG. 13. Moreover, movement of the front portion30may be enabled when the third coupling member214is disengaged from a member of the set of teeth166as shown inFIG. 14. The third coupling member214may be made using a wire. The wire may have a square cross section to provide a greater contact surface or better engagement with members of the set of teeth166as compared to a wire having a round cross section.

The third coupling member214may have any suitable configuration. In the embodiment shown inFIGS. 12-14, the third coupling member214is generally wishbone-shaped and has an engagement portion240that may be configured to be engaged by the second coupling member212. The engagement portion240may be received by or extend through one or more slots in the latch mounting region100to help position third coupling member214. The third coupling member214may be generally symmetrically disposed about the engagement portion240and may be pivotally mounted on a portion of the head restraint assembly16, such as the latch mounting region100of the traverse member72. For example, the third coupling member214may be pivotally disposed or snap fit into one or more slots in the latch mounting region100.

A spring242may be provided that exerts a biasing force on the third coupling member214. The spring242may have any suitable configuration. The spring242may be disposed on the traverse member72and may bias the third coupling member214toward the set of teeth166.

The head restraint assembly16may move with respect to the support post22in three general manners. First, the headrest20may move along the support post22generally up and down (e.g., away or toward the seat back14) when the traverse member72moves along the support post22. Second, the headrest20may move in a fore-aft direction that may be generally perpendicular to the up and down direction of movement when the support frame74moves across the traverse member72. During fore-aft movement, both the front and rear portions30,32may move generally toward or away from the head of a seat occupant. Third, the front portion30of the headrest20may flex or fold when it moves toward or away from traverse member72. During such movement, the pivot members76may pivot and move lateral sides of the front portion30in an angular manner, such as by flexing or folding forward and inward toward the center of the front portion30. The headrest20may move in one or more of these three general manners when the latch subsystem80is in the unlatched position and may be inhibited from moving in any manner when in the latched position. For instance, the front portion30may not flex in one or more embodiments.

Operation of the head restraint assembly16in accordance with at least one embodiment may be described as follows. To enable movement of the head restraint assembly16the button64may be actuated. Actuation of the button64may exert force on the first coupling member210and move the first coupling member210toward the second coupling member212. Actuation of the second coupling member212may disengage the support post engagement portion220from the support post22, thereby enabling vertical movement of the traverse member72along the support post22. In addition, actuation of the second coupling member212may move the second end224toward the third coupling member214to exert force on the engagement portion240. The third coupling member214may then disengage from the set of teeth166when sufficient force is provided to overcome the biasing force of the spring242. The front and/or rear portions30,32of the headrest20are then free to move with respect to the traverse member72in the fore-aft direction and/or by flexing or folding movement in the second and third manners described above.

The head restraint assembly16may simultaneously move in multiple directions when the latch subsystem80is in the unlatched position. Such movement may be in response to force exerted by a seat occupant. Optionally, movement may be aided by or in response to force exerted by an actuator, such as an electrical or electromechanical actuator such as a motor, solenoid, spring, linkage, or the like.

The front portion30and rear portion32of the headrest20may both move in the same direction when the headrest moves in a second manner (fore-aft direction) and/or a third manner (folding movement). Although the front and rear portions30,32may move in the same direction, the distance of movement of the front portion30may differ from that of the rear portion32. The different distances of movement may be expressed as a ratio. An exemplary ratio is illustrated by comparingFIGS. 4-6. In these figures the front portion30moves a greater distance than the rear portion32over a predetermined distance. A 2:1 ratio is illustrated in these figures in which the front portion30moves twice the distance as the rear portion32over a range of travel. The difference in the distance of relative movement may be due to actuation of the pivot members76and may be independent of the vertical position of the traverse member72along the support post22.

InFIG. 4, the headrest20is shown in a fully retracted position in which the headrest20is moved as far rearward as possible. In this position, the back portion142of the support frame74may be disposed at a maximum distance from the support post22and the pivot members76may be retracted such that a front surface of the front portion30is at a point of minimum flexure or folding. Reference positions of the front and rear portions30,32are designated by lines A and B, respectively.

InFIG. 5, the headrest20is shown after being moved forward to an intermediate position. The intermediate position shown may be representative of a position at the center of the range of travel. In this position, the front and rear portions30,32have moved forward to positions designated by lines A′ and B′, respectively. The distance from line A to A′ is shown as being twice the distance from line B to B′. For instance, the distance from line A to A′ may be 30 mm while the distance from line B to B′ may be 15 mm. The greater distance of travel of the front portion30may be due to movement of the pivot member76.

InFIG. 6, the headrest20is shown after being moved to a fully advanced position in which the headrest20is moved as far forward as possible. In this position, the back portion142of the support frame74may be disposed at a minimum distance from the support post22and the pivot members76may be advanced such that a front surface of the front portion30is at a point of maximum flexure or folding. In this position, the front and rear portions30,32have moved forward to positions designated by lines A″ and B″, respectively. The distance from line A to A″ is shown as being twice the distance from line B to B″. For instance, the distance from line A to A′ may be 60 mm while the distance from line B to B′ may be 30 mm. The greater distance of travel of the front portion30may be due to movement of the pivot member76.

Movement of the head restraint assembly16may be disabled when the latch subsystem80is in the latched position. For instance, when the button64is released, the spring242may bias the third coupling member214into engagement with the set of teeth166, bias the third coupling member214against the second coupling member212to actuate the second coupling member212against the support post22, and bias the second coupling member212against the first coupling member210to return the button64and latch subsystem80to the latched position.