Abstract: A backrest is provided, whereby a frame-shaped base structure of which is made of a dimensionally stable plastic, The base structure being formed from beams. The frame-shaped base structure includes at least one functional element between the beams, and the at least one functional element is made only of a plastic and/or as a plastic-coated insert. Injection molding is proposed as a production method.

Abstract: A vehicle seat includes a seat back having a backrest, a backrest support, and a linkage arranged to interconnect the backrest and the backrest support. The linkage is configured to support the backrest for movement relative to the backrest support.

Abstract: An office chair (1) comprising a seat (2), a backrest (3) including a lumbar support (4), an actuator device (8) arranged to enable adjustment of the lumbar support (4) between an inactive position in which it follows the general shape of the backrest (3), and a fully active position in which it is adjusted outwards forwardly from the backrest (3) in order to support the lumbar back portion of a person seated on the seat (2).

Abstract: A seat includes a seat pan, having a seat pan front edge and a seat pan rear edge. The seat pan front edge defines a first pivot point and the seat pan rear edge defines a second pivot point. A lumbar cushion, having a lumbar cushion top edge and a lumbar cushion bottom edge, is articulately disposed adjacent to the seat pan rear edge. A backrest, having a backrest top edge and a backrest bottom edge, is articulately disposed adjacent to the lumbar cushion top edge. A headrest, having a headrest top edge and a headrest bottom edge, is articulately disposed adjacent to the backrest top edge. The seat pan, the lumbar cushion, the backrest, and the headrest are positionable with respect to one another such that seat is configurable into at least one of a taxi, takeoff and landing position, a limited recline position, a napping position, and a sleeping position. The first pivot point remains in a substantially fixed position for each of the positions.

Abstract: A seat for an aircraft is provided that includes a seat pan, having a seat pan front edge and a seat pan rear edge, a backrest, having a backrest top edge and a backrest bottom edge, where the backrest bottom edge is articulately disposed adjacent to the seat pan rear edge, a headrest, having a headrest top edge and a headrest bottom edge, where the headrest bottom edge is articulately disposed adjacent to the backrest top edge, a tracking device disposed beneath the seat pan and being attachable to a floor of the aircraft, the tracking device permitting the seat pan to translate in at least one of a lateral direction and a longitudinal direction, and a swivel connected between the tracking device and the seat pan, permitting the seat pan to rotate with respect to the tracking device.

Abstract: A vehicle seat includes a seat pan, where the seat pan front edge defines a first pivot point and the seat pan rear edge defines a second pivot point. A swivel is disposed beneath and supporting the seat, permitting the seat to rotate about a pivotal axis. First and second armrests are disposed on either side of the seat pan. A first control is positioned in the first armrest to lock and unlock movement of the seat in at least one of lateral and longitudinal directions. A second control is positioned in the second armrest to lock and unlock at least the swivel.

Abstract: A vehicle seat includes a seat, a swivel connected to and rotatably supporting the seat, a swivel frame connected to the swivel, a first lateral rail supporting the swivel frame, the first lateral rail permitting the swivel frame to move in a first direction, and a first longitudinal rail supporting the first lateral rail such that the first lateral rail is movable along the first longitudinal rail, thereby permitting the swivel frame to move in a second direction that is perpendicular to the first direction.

Abstract: A seat for a vehicle includes a seat pan, where the seat pan front edge defines a first pivot point and the seat pan rear edge defines a second pivot point, a backrest articulately disposed adjacent to the seat pan rear edge, a headrest articulately disposed adjacent to the backrest top edge, and two armrests positioned adjacent lateral sides of the seat pan. The armrests define top surfaces that are disposed a predetermined height above the seat pan top surface. The seat is configurable into at least one of a taxi, takeoff and landing position, a napping position, and a sleeping position. The first pivot point remains in a substantially fixed position for the taxi, takeoff and landing position, the napping position, and the sleeping position. The predetermined height varies for each of the taxi, takeoff and landing position, the napping position, and the sleeping position.

Abstract: The present invention relates to an anatomic desk chair for office or home work, which has a displacement system composed by a plurality of wheels which allow the user to move from one location to another, wherein the chair is characterized by comprising a backrest having a frame with a tire-type assembly system, i.e. wherein the backrest as such is made of an elastomeric material and is assembled in the frame by pressure and these are adjusted through a series of screws attaching the frame and the counter-frame. Thus, the assembly system is composed by a back support or “skeleton” which corresponds to a piece injected in an elastomer requiring of a stretching process subsequent to the injection in order to obtain the shape and dimension sufficient to assembly in the frame with a tire-type system, after such skeleton-frame assembly the counter-frame is assembled through screws as previously indicated.

Abstract: A seating structure includes a backrest member having an upper edge, opposite side edges and a lower edge. The backrest member has a forwardly facing convex shape formed along a vertical centerline thereof between the upper and lower edges. The lower edge has a forwardly facing concave shape. The lower edge has outer portions positioned forwardly of an entirety of the upper edge.

Abstract: A seating, including a sling seating, can have adjustable and/or non-adjustable cushions. An occupant of the seating can adjust the thickness and support provided by an adjustable cushion. The adjustable cushion can include an open cell foam in an airtight envelope. The occupant can open a control valve connected to the envelope to let air out of the airtight envelope while the occupant applies external pressure to the open cell foam, which decreases the thickness of the adjustable cushion as the open cell foam compresses. The occupant can close the valve to restrict airflow into and out of the envelope at a desired thickness of the adjustable cushion. The occupant can subsequently open the valve to let air into the envelope while the occupant does not apply external pressure to the open cell foam, which increases the thickness of the adjustable cushion as the open cell foam expands.

Abstract: An office chair is provided having a back assembly which is configured to provide supplemental support to the back of a chair occupant in addition to the support provided by the primary support surface of the chair back. The chair back includes a lumbar support unit having a lumbar support pad wherein asymmetric support is provided to the left and right halves of the lumbar pad. As such, the asymmetric support loads are independently adjustable to more comfortably support a chair occupant. The chair back also includes a pelvic support pad which is disposed vertically adjacent to the lumbar support.

Abstract: In order to provide a lumbar support apparatus whose position can be adjusted by a simple structure and which can softly support a lumbar vertebra portion of a sitting person, a lumbar support apparatus of a chair according to the present invention is configured by two lumbar support members 10 which are separated into left and right parts, each of the lumbar support members 10 includes a lumbar support portion 11 supporting the lumbar vertebra portion and a stay portion 12 supporting the lumbar support portion, and an end portion of the lumbar support stay portion 12 is rotatably connected and attached to a back frame 2 via a rotation shaft 14, so that the position of the lumbar support portion 11 in the height direction can be adjusted by moving the same such that its distal end side is moved in a circular manner about the rotation shaft 14.

Abstract: A seat back frame for the vehicle seat, includes a pair of side frames that are disposed on both sides in a seat width direction; and a supporting plate that has both ends connected to a bottom section of each of the side frames, wherein the supporting plate is at least disposed along an interval between a first height that corresponds to an upper part of a lumbar vertebra of an occupant seated in the seat and a second height that corresponds to a lower part of the lumbar vertebra, and curves in a manner such that, in a cross-section along with a vertical direction, the supporting plate bulges forward along a line from the first height to the second height.

Abstract: A vehicle seat is provided. The vehicle seat includes a back frame, and a bracket assembled to the back frame and configured to reduce a load applied to a neck of an occupant by shock of a rear collision when the rear collision occurs in a vehicle, wherein the bracket has an inclined surface that is substantially parallel with a torso line at a normal posture of a seatback.

Abstract: A power lift lumbar support system for a furniture member includes a lumbar pad. A scissoring portion is rotatably connected to the lumbar pad and moves the lumbar pad between a fully retracted and a fully extended position. A lumbar actuation portion is connected to the scissoring portion and drives the scissoring portion using a powered actuator to displace the lumbar pad. A carrier support rod has first and second carriers slidably disposed on the carrier support rod. The scissoring portion is connected to each of the first and second carriers. Displacement of the first and second carriers toward each other operates through the scissoring portion to displace the lumbar pad away from the carrier support rod and toward the fully extended position.

Abstract: A variable lumbar support assembly for a seatback of a vehicle seat assembly includes a support bracket and a lumbar member. The support bracket has an upper end, an opposite lower end, and a pair of side rails extending between the upper end and the lower end. The support bracket has a curved central portion positioned between the upper and the lower end. The lumbar member is slidingly attached to the pair of side rails of the support bracket. The slidingly attachment of the lumbar member along the pair of slide rails provides both a vertical displacement and a fore and aft displacement of the lumbar member.

Abstract: A seating device with reduced bulk, for example for an aircraft. This seating device comprises a backrest which describes a circular translational movement towards the front and upwards of the device when the seating device is brought to the retracted configuration. A seating structure is provided comprising a bearing piece on which are fixed, side by side, a plurality of seating devices with reduced bulk. An aircraft is provided comprising a seating device with reduced bulk mounted in its cabin.

Abstract: A therapeutic recumbent chair having back and leg cushions and including an adjustable lumbar support member and an adjustable scapula region support member, each within the back cushion and movable toward and away from a front surface of the back cushion for adjustment of the support members against the back cushion for comfortably supporting the back of a user when the user is seated in the chair. Varying the positions of the adjustable lumbar support member and of the adjustable scapula region support member allows the chair to be configured to properly support a user's back when the user is in a recumbent position, for minimizing back problems of a user and for treating back disorders.

Abstract: A chair including a seat member for supporting a user, a backrest member mounted on the seat member, an adjustable platform attached to the backrest member in which the adjustable platform is selectively adjustable to provide a desired contour for supporting the back of a user seated within the chair, and a multipoint adjustment mechanism configured to adjust the adjustable platform along multiple locations of the platform to provide a desired contour for supporting the back of a user seated within the chair. The chair may be custom fitted to a specific user where the curvature of a user's back (e.g., in the spinal region) is measured relative to an idealized curvature, and the multi-point adjustment mechanism of the chair may be dialed in to improve the user's posture as the user uses the chair.

Abstract: An adjustable support system for a seat having a fixed frame includes a support movable from a first position to a second position relative to the frame. An actuator is coupled to only the support and is configured to move the support between the first and second positions. A member is operatively associated with and movable by the actuator. A flexible cable has a first end coupled to the member for travel along the length of the member and a second end coupled to the fixed frame such that movement of the member by the actuator causes the flexible cable to move the support between the first position and the second position.

Abstract: An actuator system for controlling a lumbar support includes a wire fixed and coupled with a lumbar support at one end; a driving motor rotatable in either the clockwise or counterclockwise direction; a worm coupled with the driving shaft of a driving motor; a deceleration part having a worm gear and a screw which decelerates the power of the driving motor; a slider connected to the other end of the wire, and having a protrusion portion and a spiral groove so as to carry out rectilinear reciprocating motion according to the rotation direction of the driving motor; and a housing inserted by the slider and having a wire-passing hole, a connection hole, a mounting hole and a guide hole, wherein the bending degree of a lumbar support may be automatically controlled by rotation driving force applied in a set range, thereby providing riding comfort to passengers.

Abstract: A lumbar support device includes: a seat back frame; a warped plate supported by the seat back frame to press a back of a seated person; and a reinforcing plate that reinforces the warped plate, the reinforcing plate being able to curve together with the warped plate. The warped plate includes a holder that holds a first end portion of the reinforcing plate, and a non-interference portion that allows movement of the reinforcing plate relative to the warped plate.

Abstract: A seat back frame includes: a base frame; a movable frame supported for movement in a frontward-rearward direction with respect to the base frame; and a biasing member biasing the movable frame frontwardly and permitting a rearward movement of the movable frame in response to a load having a given value or more. The base frame has an upper frame section supporting a headrest, and two side frame sections extending in an upward-downward direction on laterally opposite sides of the upper frame section. The movable frame has a back-receiving section located between the side frame sections, and two side support sections on laterally opposite sides of the back-receiving section to project forward from the side frame sections. Front ends of the side support sections are disposed to stop a rear surface of the pad that receives a rearward load from a back of an occupant.

Abstract: A backrest inclination structure for lumbar support enables a backrest to enter a free state when a user sitting at any position of a chair lifts a lever of a spring continuous control unit, such that the backrest fits the user's moving back when the backrest is configured for movable inclination. Hence, the backrest can move together with the user's back ergonomically to provide lumbar support. Accordingly, the user can sit comfortably on the chair and be free from lumbago and kyphosis which are common among sedentary individuals.

Abstract: An apparatus for sitting, including: a keystone assembly which connects various parts of the apparatus; a back that provides support for at least a person's back or shoulders; a floating lumbar support, which provides support for a person's lower back, attached to the keystone assembly; a seat that can adjust between a forward tilted and reclined position; a plurality of rollers, disposed on the keystone assembly, on which the seat rests; a central column, attached to the keystone assembly, on which the seat can spin; and a lower torsion spring connected to the seat and disposed on the keystone assembly allowing controlled movement of the seat.

Abstract: The present device includes a sacral support for a person sitting in a chair with a seat back. The sacral support includes a rigid base having a bottom surface, a peripheral edge, and a top surface. The top surface includes a plurality of pegs projecting upwardly away therefrom. An elastomeric cushion includes a bottom surface, a peripheral edge, and a convex top surface. The bottom surface of the cushion includes a plurality of apertures adapted to receive the pegs therein. With the cushion engaged with the base at the pegs and apertures thereof, the sacral support may be positioned against the seat back of the chair to produce pressure against the person's sacrum when seated. The sacral support includes a plurality of elastomeric cushions, each cushion having a unique height to be selected as desired by the person. Further, the device includes a mount to be used with backless chairs.

Abstract: A backrest structure for a seat comprising a backrest frame which has a support structure and a front side facing the back of a seat user, a backrest cushion at the backrest frame a lumbar support mounted on the front side of the backrest frame for supporting the back of a seat user, an adjusting device for adjusting the position of the lumbar support perpendicular to the extension plane of the backrest frame and a curving element arranged on the front side of the backrest frame between the lumbar support and the backrest cushion. The curving element is secured to the support structure and the adjusting device acts on the curving element in order to adjust a curvature of the curving element. Furthermore, the backrest structure comprises at least one connecting element being connected to the curving element and the support structure, which connecting element applies a pre-tensioning force to the curving element in order to maintain the curving element in contact with the support structure.

Abstract: A vehicle seat is provided comprising: a seat back frame having a side frame; a headrest for supporting a head of a seat occupant; a load receiving member disposed behind the seat occupant and movable rearward in response to a load from the seat occupant; and a link member mounted to the seat back frame and rearwardly movable; wherein: a rearward movement of the load receiving member moves the link member rearward and reduces a distance between the head of the seat occupant and the headrest; the load receiving member is provided with a first through-hole and a second through-hole; and the first through-hole and the second through-hole are disposed in a same horizontal plane.

Abstract: A chair assembly includes a back shell member including a laterally-extending top portion, a laterally-extending bottom portion and a pair of longitudinally-extending side portions extending between the top portion and the bottom portion and cooperating therewith the defined open space therebetween, and a cover having a first surface adapted to support a seated user and a second surface opposite the first surface, wherein the cover is positioned over the back shell member to cover at least a portion of the open space, and wherein the cover comprises an elastomeric material having a longitudinal direction compliance to lateral direction compliance ration of at least 3:1.

Abstract: A lumbar support system for a seat backrest having a fixed frame includes a lumbar support coupled to the fixed frame that is movable from a first position to a second position and a motor for moving the lumbar support. A threaded member is operatively associated with the motor such that the motor rotates the threaded member about an axis. A traveling member is operatively associated with the threaded member such that rotation of the threaded member translates the traveling member along the threaded member. The system further includes a flexible cable having a first end and a second end. The first end is coupled to the traveling member for movement therewith and the second end is coupled to the fixed frame such that translation of the traveling member in response to rotation of the threaded member moves the lumbar support element from the first position to the second position.

Abstract: A lumbar support system for a seat backrest having a fixed frame includes a lumbar support coupled to the fixed frame that is movable from a first position to a second position and a motor for moving the lumbar support. A threaded member is operatively associated with the motor such that the motor rotates the threaded member about an axis. A traveling member is operatively associated with the threaded member such that rotation of the threaded member translates the traveling member along the threaded member. The system further includes a flexible cable having a first end and a second end. The first end is coupled to the traveling member for movement therewith and the second end is coupled to the fixed frame such that translation of the traveling member in response to rotation of the threaded member moves the lumbar support element from the first position to the second position.

Abstract: A seat having a trim carrier. A flexible region includes a base portion integrally connected with the trim carrier and a distal portion. A connector includes a first end connected to the distal portion and a second end connected to a motor. Actuation of the motor draws the connector and consequently the distal portion downward toward the base portion, thereby arcing the flexible region.

Abstract: A chair of the type commonly found in a home or office and having a stationary back, a pair of arms, and a rotatable seat cradle that is located between the arms. The seat cradle includes a lumbar portion lying against the stationary chair back to support the user's lower back and a seat cushion portion to support the user's pelvis. The lumbar portion and the seat cushion portion of the seat cradle are connected to one another so as to rotate together as a unit relative to the stationary back and the arms of the chair. By virtue of the foregoing, the hips and spine of the user will be continuously aligned whenever the user shifts his weight in the chair, whereby to maximize user comfort and improve user posture.

Abstract: A shock absorber for vehicle seat is provided. The shock absorber is suspended on a seat frame so as to elastically support a pad. The shock absorber includes: a plurality of wires that are disposed in parallel to the seat frame, both ends of the wires being locked to the seat frame; and a resinous member that connects the wires to each other, the resinous member having a bent portion, wherein the resinous member is elastically deformable in a direction in which the wires are opposed each other in accordance with a deformation of the bent portion.

Abstract: A lumbar support plate which is supported movably in a front/rear direction in a back frame that supports a headrest, and a biasing member which supports the lumbar support plate, are provided. A clutch mechanism which enables an output member to rotate by a rotating operation of a handle shaft, and an adjustment member which is capable of adjusting the front/rear position of the lumbar support plate in relation with an output member of the clutch mechanism are also provided. Also provided is a linking release mechanism which temporarily releases linkage with the clutch mechanism and permits rearward movement of the lumbar support plate, when a load equal to or greater than a prescribed value is applied to the lumbar support plate.

Abstract: An office chair (1) comprising a seat (2) and a backrest (3), wherein the backrest (3) includes a lumbar support (4), which is adjustable between an inactive position in which it follows the general shape of the backrest (3), and a fully active position in which it is curved outwards forwardly from the backrest (3) in order to support the lumbar back portion of a person seated on the seat (2) of the chair (1).

Abstract: A backrest for supporting the back of a seated person, intended and adapted to form part of an article of seating furniture, such as a wheelchair, has the feature that the backrest consists of two parts, that is: a lower backrest part for supporting the sacral-lumbar part of the back of a seated person, and an upper backrest part for supporting the lumbar-thoracic part of the back of a seated person; both backrest parts can be moved independently of each other relative to the carrier; and a carrier therefor which has three degrees of freedom in a vertical plane, perpendicularly of the main plane of the backrests, relative to the frame tube, i.e. two degrees of freedom of translation corresponding to height and depth, and one degree of freedom of rotation around a horizontal rotation axis.

Abstract: A vehicle seat is provided that includes a seat back frame, a headrest, a pressure receiving member that supports the body of the occupant and moves independently from the headrest, and pivoting members that are disposed in at least one of side portions of the seat back frame, are linked to the pressure receiving member, and can move independently from the headrest under a predetermined impact load. The entirety of the pressure receiving member moves toward the rear of the vehicle under a predetermined impact load that is greater than a normal seating load.

Abstract: An apparatus for sitting, including: a keystone assembly which connects various parts of the apparatus; a back that provides support for at least a person's back or shoulders; a floating lumbar support, which provides support for a person's lower back, attached to the keystone assembly; a seat that can adjust between a forward tilted and reclined position; a plurality of rollers, disposed on the keystone assembly, on which the seat rests; a central column, attached to the keystone assembly, on which the seat can spin; and a lower torsion spring connected to the seat and disposed on the keystone assembly allowing controlled movement of the seat.

Abstract: There is provided a seat back device including: a seat back that is placed on a rear side of a vehicle cabin and has a movable portion that is movably disposed in correspondence to a lower back region of a seated passenger and a forwardly collapsible portion that is forwardly collapsibly disposed on a vehicle upper side of the movable portion; a frame member that is disposed inside the seat back and in which is formed an open portion that has a size including the movable portion and the forwardly collapsible portion and that makes the vehicle cabin and a luggage compartment communicate; an angle adjusting mechanism which adjusts the movable portion about an axis along a vehicle width direction to a predetermined angle; and a trunk-through mechanism which forwardly collapses the movable portion and the forwardly collapsible portion from the seat back and opens the open portion.

Abstract: An adjusting device for a lumbar support includes a pair of spaced guide members. A first adjusting member is coupled to the pair of guide members and displaceable along the pair of guide members and configured such that the lumbar support is adjusted when the first adjusting member is displaced. A second adjusting member is displaceable along the pair of guide members. A drive mechanism for effecting an adjustment of the lumbar support includes a motor provided on the first adjusting member so as to be displaceable along the guide members jointly with the first adjusting member.

Abstract: A lumbar support operation member comprising a shaft attachment portion that is configured so as to be fixed to a rotation shaft that transmits rotation force to a moving mechanism of a lumbar support provided to a seatback and that is positioned at a side portion of the seatback; and operation portions that are provided at an radial direction outside of the shaft attachment portion, that are separated from each other in a circumferential direction of the shaft attachment portion, and that make the shaft attachment portion rotate.

Abstract: An actuator arrangement for a seat includes a plurality of traction members and an actuator coupled to the plurality of traction members. The actuator has at least one first drive member which is rotatably supported. The actuator may include a second drive member which is supported moveably relative to the at least one first drive member. The traction members are coupled to the at least one first drive member so that rotation of the at least one first drive member gives rise to a cyclical change in the traction applied by the traction members.

Abstract: A vehicle seat includes: a holder assembled to a back frame, the holder configured to receive a backrest load of a seated person via a pad member; a vibration device assembled to a rear side of the holder, the vibration device configured to give a local stimulus to a seated person's waist; an air massage device disposed in a through hole formed in a thickness direction of the pad member, the air massage device configured to locally press a seated person's back; and a lumbar support device configured to change a projecting amount of a receiving surface of a seat back, wherein the lumbar support device has a rod configured to be movable between an advancing position and a retreating position to change the projecting amount of the receiving surface of the seat back, and wherein the rod is disposed between the holder and the vibration device.

Abstract: A cushion-less passenger seat. The passenger seat includes spaced left and right spreaders, each having a front and rear leg with top and bottom ends and a seating surface formed from a flexible bottom diaphragm attached to and extending between the left and right spreaders. The passenger seat also includes a lumbar support having lower and upper sections and front and back sides formed from a flexible diaphragm. The lower section of the lumbar support is attached to and between the left and right spreaders. The lumbar support upper section extends upwardly above the seat's rear legs and seating surface.

Abstract: A seatback device configured to elastically support a planar elastic body between left and right side frames. The seatback device includes left and right first springs and left and right second springs. The left and right first springs have axes respectively, extending in the width direction of the vehicle. The upper parts of the left and right sides of the planar elastic body body are connected to the left and right side frames through the left and right first springs. The left and right second springs have axes, respectively, extending in the front-and-rear direction of the vehicle body. The lower parts on the left and right sides of the planar elastic body are connected to the left and right side frames through the left and right second springs.

Abstract: A back support is pivotally oriented to locate a pivot point relative to posterior superior iliac spines of a seated user, such that when an upper portion of the back support contacts the upper torso of the user and moves to a desired angular orientation to balance the upper torso over the pelvic area, the back support transfers support to the posterior superior iliac spines to maintain the pelvic skeletal structure in alignment. A lower portion of the back support angularly contacts, supports and confines gluteal and buttocks tissue of the user independently of the degree of pivotal orientation of the upper portion.

Abstract: A backrest frame is provided with a cushion plate of one substantially square plate form positioned behind the waist from the upper part of the back of a vehicle seat occupant, movably back and forth by way of a plurality of upper and lower parallel seat springs, one end of either one of a pair of right and left seat springs of the plurality of upper and lower parallel seat springs is connected to a pair of lower link mechanisms provided rotatably on the backrest frame, and a rear end collision sensor is formed by the cushion plate between the seat springs for moving a headrest forward, and a coupling part of the other end of the seat spring is directly attached to the lower link mechanism.

Abstract: An adjusting device for a lumbar support comprises a pair of spaced guide members, an adjusting member coupled to the pair of guide members, and a drive mechanism for effecting an adjustment of the lumbar support. The adjusting member is displaceable along the pair of guide members and configured such that the lumbar support is adjusted when the adjusting member is displaced. The drive mechanism comprises a motor, which is provided on the adjusting member so as to be displaceable along the guide members jointly with the adjusting member. The motor may be coupled to a shaft having a structured exterior surface, the drive mechanism being configured to effect a relative displacement between the adjusting member and the shaft.