Patent Application
20250151913
The present invention relates to a cable tensioning system, a mounting plate assembly, a retraction cam, a damper system, an extension and retraction system for extending and retracting a leg rest of, e.g. airplane seat and a method for operating the extension and retraction system.
Retraction cams and mounting plates for seats are generally known.
Embodiments provides a cable tensioning system comprising a mounting plate assembly with a mounting plate and a retraction cam mounted to the mounting plate and configured to pivot about a primary axis, wherein the retraction cam comprises a cam body and a spur body having a cable sheave groove, wherein the mounting plate assembly is fixedly secured to a mounting fixture of a leg rest of a seat, and wherein the cable sheave groove is configured to receive a cable fixed to an extension frame of the leg rest, the extension frame being movable relative to the mounting fixture.
Embodiments provide a retraction cam comprising a cam body having a pivot axle, a spur body arranged on the cam body and pivotably guided by the cam body, and a tensioning spring secured to the cam body and the spur body and allowing the spur body to pivot on the cam body, wherein the pivot axle of the retraction cam is pivotable about a mounting point of an external device.
Embodiments provide a mounting plate assembly for a leg rest system. The mounting plate assembly may comprise a mounting plate, a support plate coupled to the mounting plate, and a swing arm assembly mounted between the mounting plate and the support plate, wherein the swing arm assembly comprises a swing arm shaft, a groove follower mounted to the swing arm shaft, and a lever arm mounted to the swing arm shaft. The mounting plate assembly may further comprise a first bushing installed in the support plate configured for guiding the swing arm shaft and a second bushing installed in the mounting plate configured for guiding the swing arm shaft.
Embodiments provide a damper system comprising a damper housing assembly and a rotational damper plate assembly. The rotational damper plate assembly may comprise a damper plate having a hook feature configured to engage a lever arm of a swing arm assembly and a ramp surface configured to guide the lever arm, the hook feature and the ramp surface being formed on a connection surface between a first main surface and a second main surface of the damper plate and a torsion spring arranged between the damper housing assembly and the rotational damper plate assembly.
Embodiments provide a method for operating a system. The system may comprise a retraction cam and a mounting plate assembly, wherein the retraction cam is rotatably fixed to a mounting plate of the mounting plate assembly and comprises a cam body and a spur body, and wherein one end of a cable is fixed to the retraction cam and another end is fixed to an extension frame of a leg rest of a seat. The method may comprise retracting the leg rest from a deployed position to a stowed position, while retracting, applying, by a torsion spring a force to the retraction cam thereby pivoting the retraction cam and while retracting, applying, by a tensioning spring a force to the spur body thereby pivoting the spur body against the cam body.
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
Embodiments provide retraction cam/cable tensioning systems for deploying and stowing a leg rest of a seat by interacting with a retraction cable. These systems may be controlled via a deployment and stowage mechanism, which may be driven by a gearbox/motor 150 arranged at the seat. The leg rest may be mechanically stowed by pushing it from and a deployed position towards a stowed position by a user or passenger.
Other embodiments provide a retraction cam comprises two parts, a cam body and a spur body. These two parts are movable against each other and can adjust an effective arc-length of a cable fixed to the spur body. The cam body and the spur body have several advantageous features so that they can operate smoothly and without/with reduced friction.
Further embodiments provide a mounting plate assembly. The mounting plate assembly is a transition structure between the rotation of the retraction cam and the linear extension of a mounting fixture and an extension frame of a leg rest. The mounting plate assembly includes several advantageous elements.
Yet further embodiments provide a damper system for providing and improving stability of the leg rest during a fully deployed and extended orientation.
The retraction cam/cable tensioning system can also reduce the strain imparted onto the cable by using varying bend radii. The retraction cam/cable tensioning system is thereby advantageously able to provide a robust and reliable leg rest extension and retraction performance.
The gearbox/motor 150 comprises an electric motor. The gearbox/motor 150 provides power to a plurality of linkages 430-460 of the deployment and stowage mechanism 400 so that the linkages 430-460 move the leg rest 200 in a rotational and non-linear process and so that the front edge of the leg rest 200 does not contact the cabin floor of the airplane. The linkages 430-460 translate the force/torque of the rotation of the gearbox/motor 150 into a rotational and predominantly horizontal movement. The amount of torque on the system is directly dependent on the extension of the leg rest 200. The farther the leg rest 200 extends, the greater the torque the system experiences. The mechanical movement of the linkages 430-460 together with the system of the extension and retraction mechanism 3000 (see below) is responsible that the leg rest 200 does not contact the cabin floor.
The extension and retraction mechanism 3000, and in particular the retraction mechanism 900 may be operated only by the deployment and stowage mechanism 400 without the assistance of any other motor or force. The deployment process and the retraction or stowage process performed by the deployment and stowage mechanism 400 may be processes that mirror each other, e.g., reach the same end positions and move at the same rate.
The deployment and retraction linkages 430-460 are now described. Linkage 440 connects at one end to linkage 450, in a middle part to linkage 430 and at the other end to the gearbox/motor 150. Linkage 430 connects at one end to base plate 420, in a middle part to linkage 440 and at the other end to linkage 460. Linkage 450 connects at one end to the base plate 420 and to linkage 440 at the other end. Linkage 460 connects at one end to linkage 430 and at the other end to the gearbox/motor 150. Unlike the linkage 440, linkage 460 is not driven or powered by the gearbox/motor 150 but rather only secured to it. In various embodiments, linkage 460 acts to prevent linkage 440 from rotating freely.
When the leg rest 200 is moved from the stowed position to the deployed position, the mounting fixture 500 is moved relative to the seat 100 via the deployment and stowage mechanism 400 and, at the same time, the extension frame 600 is moved, at one point of the extension process, relative to the mounting fixture 500 via the extension and retraction mechanism 3000. The deployment and stowage mechanism 400 (linkages 430-460) may be the only part that provides power for deploying and retracting the leg rest 200, or the only part that provides power for shortening or extending the position between the extension frame 600 and the mounting fixture 500. In various embodiments, the leg rest 200 is essentially always placed in the same place when stowed or deployed.
The mounting fixture 500 functions as a reference point with respect to the other parts of the leg rest 200. The forces associated with the motion of the extension frame 600 and/or leg rest pad 700 are described with respect to the fixture 500.
The extension frame 600 is movably mounted to the mounting fixture 500, wherein the extension frame 600 is movable by an extension and retraction mechanism 3000.
When the leg rest 200 is deployed the motor 150 applies power to the deployment and stowage mechanism 400 and the linkages 430-460 move the leg rest 200 towards its deployed end position. While deploying the leg rest 200 the extension mechanism provides a force so that the extension mechanism moves extension frame 600 away from the mounting fixture 500. The extension mechanism may provide a permanent force (e.g., a spring) or alternatively, a force which is selectively enabled.
When the leg rest 200 is stowed the motor 150 applies power to the deployment and stowage mechanism 400 and the linkages 430-460 move the leg rest 200 towards its stowed end position. While stowing the leg rest 200 the retraction mechanism 900 provides a force so that the extension frame 600 moves towards the mounting fixture 500. At the beginning of the process, the linkages 430-460 pull the mounting fixture 500 backwards. At this point the extension frame 600 does not (yet) move relative to the mounting fixture 500. When the nose 431 of linkage 430 touches the cam stud 1190 of the cam 1000 the extension frame 600 starts moving towards the mounting fixture 500. The stowage process and the retraction mechanism 900 are described in principle in U.S. patent application Ser. No. 18/238,365.
This application provides embodiments of the extension and retraction system mechanism 3000 and in particular the interaction between the mounting plate assembly 2000, the retraction cam 1000 and the damper system 2900.
The tensioning retraction cam (or retraction cam) 1000 comprises two main parts. A retraction cam body 1100, also called cam body, which is mountable or mounted to and rotatable about a mounting point 2105 of a mounting plate 2100 (part of the mounting assembly 2000) and a tensioning spur body 1200, also called spur body, which is mounted or mountable to and rotatable about the retraction cam body 1100.
The retraction cam 1000 comprises a cam body 1100 and a spur body 1200 arranged on the cam body 1100 and pivotably guided by the cam body 1100. The retraction cam 1000 further comprises a torsion spring 1600 and a tensioning spring 1700. Both are housed between the cam body 1100 and the spur body 1200 and allowing the spur body 1200 pivot about the cam body 1100. The torsion spring 1600 is configured to provide torsion between the retraction cam 1000 and mounting plate 2100 and the tensioning spring 1700 is configured to provide tension between the cam body 1100 and the spur body 1200.
The retraction cam 1000 also comprises two bearings, a first bearing 1400 and a second baring bearing 1500, located between the cam body 1100 and the spur body 1200, the two bearings 1400, 1500 providing a low friction connection between the cam body 1100 and the spur body 1200.
The retraction cam 1000 further comprises a torsion spring-spur retainer 1300 (shown in detail in
The retraction cam 1000 finally comprises a damper groove profile 1180. The damper groove profile 1180 is secured to the cam body 1100 and configured to guide a groove follower 2220 of a swing arm assembly 2200.
As shown in
The cam body 1100 shows the previously mentioned rotation stabilizing flange 1140 on a portion of the connection surface 1106. The first side 1104 of the cam body 1100 comprises a recessed (shallow) channel 1130 for receiving the first bearing 1400 at the top of the cam body 1100, an internal spring cavity (recess) 1110 for receiving and arranging the tensioning spring 1700 below the recessed channel 1130, a torsion spring position cavity 1120 for receiving and arranging the torsion spring 1600 below the internal spring cavity 1110 and an opening 1150 extending through the cam body 1100 called the rotational hard limit slot. The rotational hard limit slot 1150 has an upper limit 1152 and a lower limit 1154 and is located between the internal spring cavity 1110 and recessed channel 1130. The cam body 1100 further comprises a pivot axle elevation 1175 at the pivot axle 1170, which is surrounded by the torsion spring position cavity 1120 and which is configured to be mounted to the mounting plate 2100.
The internal spring cavity 1110 is a volume of or recess in the cam body 1100 (on the first mains surface 1104) that is configured to house the auto tensioning spring 1700. The internal spring cavity 1110 prevents the spring 1700 from rubbing on other parts of the retraction cam 1000. The auto tensioning spring 1700 is secured to the cavity 1110 at one end, e.g., with a countersunk screw head 1115 with a larger OD than the ID of the spring hook 1710. The spring 1700 is secured to the spur body 1200 with the other end 1730.
The torsion spring position cavity 1120 is a volume of or a recess in the cam body 1100 (on the first main surface 1104) that is configured to house the torsion spring 1600. It can contain or hold the torsion spring 1600. One leg (first torsion spring leg 1620) of the torsion spring 1600 is fixed or secured in the torsion spring position cavity 1120 while the other leg (second torsion spring leg 1640) interacts with an external interface such as the static torsion spring catch 2800. The torsion spring 1600 is arranged in the cavity 1120 and the torsion spring-spur retainer 1300 positions the torsion spring 1600 in an optimal orientation relative to the cavity 1120. The torsion spring 1600 is able to provide (optimized) potential energy. This may be provided by the torsion spring leg clearing 1125, which provides a surface on which the second leg 1640 of the torsion spring 1600 rests and is movable. The torsion spring leg clearing 1125 is a space with unobstructed access to the static torsion spring catch 2800. On this clearing, the second torsion spring leg 1640 is able to move about a 135 degree (or 125 degrees-145 degrees, or 130 degrees-140 degrees).
The recessed channel 1130 on the first side 1104 is an elongated channel that is configured to receive the intermediate bearing 1400.
The rotation stabilizing flange 1140 is a feature at a portion of the connection surface 1106 (outer edge) of the cam body 1100. This flange 1140 is located adjacent to the rotation stabilization flange channel 1260 of the spur body 1200 when the retraction cam 1000 is assembled. The rotation stabilizing flange 1140 comprises a thin and flat surface which, when in an assembled state, interacts with the rotation-stabilization flange channel 1260 and the second bearing 1500 via compression. The compression is transferred to the first bearing 1400 providing stability via the interaction of low friction surfaces applying forces against each other.
The hard limit slot 1150 is an opening or an elongated through hole that extends from one of the main surfaces 1104 to the other one of the main surfaces 1108 of the cam body 1100. The hard limit slot 1150 is able to set the amount of tensioning for the cable 920. The slot 1150 is configured to receive a fastener such as a shoulder bolt, screw or clamp 1280 that is fixable to the spur body 1200. The allowable rotation can be set to 45 degrees, or to 40 degrees-50 degrees or 35 degrees-55 degrees between the upper rotation limit 1152 and lower rotation limits 1154. The fastener 1280 also acts as a secondary means to ensure that both the cam body 1100 and the spur body 1200 are not separated under excessive/nonplanar loading.
The pivot axle 1170 (and the pivot axle elevation 1175) is surrounded by the torsion spring position cavity 1120 and is configured to be pivotally mounted on the mounting plate 2100.
A cam stud 1190 is also rotatably mounted to the first main surface 1104 of the cam body 1100.
The second main surface comprises a recess in which the damper groove profile 1180 is arranged and secured (see, e.g.,
The spur body 1200 is a metal plate (such as an aluminum plate) with a first surface 1204 and a second surface 1208 opposite the first surface 1204 and a connection surface 1206 connecting the first surface and the second surface 1204, 1208. The first surface 1204 comprises several levels of planes, several recesses or cavities and at least one opening. The recesses or cavities are separated from each other by (one or more of) the elevated planes. The first main surface 1204 can be considered a first frame comprising different levels of planes and different recesses or cavities. The connection surface 1206 is small in size compared to the first surface 1204 and the second surface 1208 and a pivot flange 1240 is arranged thereon. A radius of the connection surface 1206 is centered on the pivot flange 1240.
The spur body 1200 has a substantially semicircular shape (equal or less than half a circle having forming an angle of 180 degrees or less, or 160 degrees to 140 degrees) in plan view. The spur body 1200 has a first extension at the lower straight side forming the pivot flange 1240 and a second extension at the lower straight side forming a step extension 1207.
The spur body 1200 comprises a cable sheave groove 1210 (
The spur body 1200 also comprises a through opening 1220. The through opening 1220 is a feature that makes the assembly of the retraction cam 1000 possible. Securing the automatic tensioning spring 1700 onto cam body 1100 without the opening 1220 would be nearly impossible due to the internal spring cavity 1110 being isolated from any external interfaces.
The spur body 1200 further comprises a retraction cam cable tension reset bumper 1230 arranged on a connection surface of a side of the spur body 1200. The reset bumper 1230 interacts with the static torsion spring catch 2800 to remove tension from the retraction cam 1000/cable 920 while the leg rest 200 is stowed. Applying constant tension to the cable 920 can result in cable damage (e.g., stretch the cable). The reset bumper 1230 is configured to relieve the retraction cam 1000/cable 920 from tension when the leg rest 200 is stowed.
The pivot flange 1240 is configured to be mounted on the pivot axle 1170. The pivot flange 1240 acts as the primary source of radial support for the tensioning spur body 1200 while the retraction cable 920 is under operational tension. When the retraction cam 1000 is assembled the pivot flange 1240 is slid on the pivot axle 1170 so that the pivot flange 1240 surrounds a part of the pivot axle 1170 adjacent to the pivot axle elevation 1175 that forms the primary axis of rotation 1010 (see e.g.,
Referring again to
The first main surface 1204 comprises a post 1250 configured to receive the rotation bearing 1500. The post 1250 is arranged in an upper portion of the first main surface 1204. The first main surface 1204 further comprises a recess or channel 1270 called the rotation bearing channel in a middle portion of the first main surface 1204. Finally, the first main surface 1204 comprises an internal spring cavity 1290, which houses the automatic tensioning spring 1700, at the lower portion of the first main surface 1204. The post 1250, the channel 1270 and the internal spring cavity 1290 are separated from each other by surface elevations. The spur pivot flange 1240 is arranged at the bottom of the spur body 1200 below the internal spring cavity 1290.
The post 1250 and the rotation baring channel 1270 may have a curved shape that has a center radius located at the primary axis of rotation 1010/pivot axle 1170/pivot flange 1240. As a result, the second bearing 1500 and the rotation stabilization flange channel 1260 (formed by the post 1250 and the second bearing 1500) may have also a center radius located at the primary axis of rotation 1010/pivot flange 1240. However, in other embodiments the radii for these features may be different.
Finally,
The support stability structures 1330 also called the torsion spring positioning insert is an elevation extending from the first main surface 1304 of the retainer 1300. When assembled the insert 1330 is inserted into and mates with the torsion spring positioning cavity 1120 of the cam body 1100 to optimize torsional output of the spring 1600. At the same time the first opening 1310 is slide on the pivot axle 1170 and fixed thereto.
The first bearing 1400 is a plate which is usable as interface between the cam body 1100 and the spur body 1200. It may be a non-metallic plate that is made of low friction plastic such as polyoxymethylene or acetal resin with a curved shape that has a center radius located at the pivot axle 1170. The first bearing 1400 is secured onto the recessed channel 1130 at the first main surface 1104 of the cam body 1100 such that it remains stationary with respect to the cam body 1100. The first bearing 1400 is secured to the recess channel via one or more removable fasteners such as screws, pins or clamps, or one or more adhesives.
The second bearing 1500 is a plate that is fixed and secured to the post 1250 of the spur body 1200 so that it is stationary with the spur body 1200. It may be a non-metallic plate that is made of low friction plastic such as polyoxymethylene or acetal resin with a curved shape that has a center radius located at the pivot flange 1240. The second bearing 1500 is secured to the post 1250 via one or more removable fasteners such as screws, pins or clamps, or one or more adhesives. The second bearing 1500 overhangs the post 1250 and forms, together with the post 1250, the rotation stabilization flange channel 1260. The rotation stabilization flange channel 1260 houses, in an assembled state, the rotational stabilizing flange 1140 of the cam body 1100 and provides guidance for this flange 1140.
The damper groove profile 1180 is fixed and secured to the second main surface 1108 of the cam body 1100. The profile 1180 may be a plate that comprises a non-metallic material such as polyoxymethylene or acetal resin that reduces the wear and tear on the system 3000 and improves efficiency of actuation. Together, the cam body 1100 and the damper groove profile 1180 are configured to guide the groove follower 2220 (in particular the long nose plunger 2222) and the swing arm assembly 2200. The damper groove profile 1180 is fixed and secured to the second main surface 1108 of the cam body 1100 by fasteners such as countersunk screws or pins, e.g., two countersunk screws.
The damper groove profile 1180 is configured to interact with the swing arm assembly 2200. The profile 1180 is designed to translate the rotation of the retraction cam 1000 into a deflection of the swing arm assembly 2200. The groove profile 1180 is secured to the second main surface 1108 of the cam body 1100. It comprises a plastic material such as polyoxymethylene or acetal resin.
The profile 1180 comprises three sections providing the following input (e.g.,
The mounting plate 2100 is described with respect to
The support plate 2300 is described with respect to
The mounting plate assembly 2000 further comprises a static torsion spring catch 2800. The catch 2800 is fastened via, e.g., screws to the second main surface of the mounting plate 2100.
The damper swing arm assembly 2200 is described with respect to
The damper swing arm assembly 2200 further includes a groove follower 2220 with a long nose spring plunger 2222 configured to engage the damper groove profile 1180 on the retraction cam 1100. The groove follower 2220 further includes a set screw 2224 for adjusting a height of the damper swing arm assembly 2200 relative to the cam mounting plate 2100 and the leg rest mounting fixture 500. The set screw 2224 provides an independent source of adjustment that overrides the lower rotational limit 1181 set by the damper groove 1180 previously described.
The damper groove 1180 is used to relate a specific rotational angle into torque to control the swing arm assembly 2200. The above section describes the region with a large relative radius 1181, which ensures the swing arm assembly 2200 has enough clockwise rotation to engage the hook feature 2522. The set screw 2224 allows for the lower limit of possible rotation for the swing arm assembly 2200 to be adjusted such that long nose spring plunger 2222 may not make direct contact with the damper groove 1180. This is beneficial because it allows for variation in relative mounting height of the swing arm assembly 2200 and damper plate assembly 2500 to be inconsequential to system performance. It also provides the ability to adjust the angular deflection required of the swing arm assembly 2200 to engage/disengage with the damper plate assembly 2500. Angular deflection is directly related to how much resistance the damper system is capable of counteracting before disengagement is possible.
To provide even further adjustability to the rotational interaction between the swing arm assembly 2200 and damper plate assembly 2500, set screw 2430 on the damper mount housing assembly 2400 has the same capability/purpose relative to the damper plate assembly's 2500 angular orientation.
The groove follower 2220 comprises an attachment point 2226 configured to receive one end of an extension spring 2700. A fastener such as a screw 2228 fixes the groove follower 2220 to the lever arm 2260 to provide support in addition to the swing arm shaft 2240.
The damper mount housing assembly 2400 further includes a radial damper axle 2426 comprising, e.g., a headless threaded shaft, which secures to the extension frame 600, and which is supported by a hole 2424 in the second main surface of the housing plate 2420 to keep the shaft perpendicular to the threaded surface.
One portion of the connection surface at one end of the damper plate 2520 forms a hook catching feature 2522 and another portion, at the top, forms a ramp surface 2524. The plate 2520 includes an extension 2538 at one end of the plate 2520 in which a rubber silencing insert 2540 can be arranged. The damper plate 2520 comprises a (cylindrical) flange extension 2528 at the first main surface 2527 on which a torsion spring 2600 is placeable. The flange extension 2528 surrounds a (circular) through hole 2529. The torsion spring 2600 sits on and is placed around the flange extension 2528. The spring 2600 is fixed with one end to a fastener 2530 (such as a shoulder bolt) arranged at the first main surface 2527 and is fixed with the other end resting against a bolt used to install the stowage linkage 300 to the leg rest extension frame 600. A thrust washer 2532 is placed on the second main surface 2531 and maybe in the through hole 2529 of the damper plate 2520. The second main surface 2531 may comprise a recess 2533 in which the thrust washer 2532 may be placed. The thrust washer 2532 is configured for contacting the extension frame 600 and reduces or eliminates friction between the damper plate 2520 and the extension frame 600 when the damper plate pivots.
The damper system 2900 is arranged and put together so that the damper housing assembly 2400 fixes the damper plate assembly 2500 to the extension frame 600 and so that the damper plate assembly 2500 is sandwiched between the damper housing assembly 2400 and the extension frame 600. The two fasteners at the extensions 2404 and the radial damper axle 2426 secure the damper housing assembly 2400 to the extension frame 600. The torsion spring 2600 sits in and between the shield cavity 2422 and the flange extension 2528. The damper plate assembly 2500 is pivotable or movable around the radial damper axle 2426. Sleeve bushings 2428 may reduce or eliminate friction between the two assemblies 2400, 2500. The assembly system prevents the torsion spring 2600 from any external influences. The long nose set screw 2430 interacts with the rubber silencing insert 2540 on the damper plate 2520, which reduces the audible noise resulting from scenarios when the damper plate assembly 2500 is rapidly rotated into the set screw 2430 long nose due to influence of the torsion spring 2600. Adjusting the set screw 2430 allows for orientation/angle of the damper plate 2520 relative to the housing plate 2420 and to control and fine-tune the two plates as the set screw 2430 provides an indexing position which the rubber silencing insert 2540 of the damper plate assembly 2500 interfaces with. Adjustment of the set screw 2430 also allows for adjustment relating to the interaction between the swing arm assembly lever arm 2260 and damper plate assembly hook feature 2522.
The mounting plate 2100 and the support plate 2300 are fixed to the mounting fixture 500 via fasteners such as screws. The retraction cam 1000 is fixed to the mounting plate 2100 at the axle mounting point 2105 and is pivotable about this point 2105 (the retraction cam 1000 pivots about the primary axis of rotation 1010) and the damper system 2900 is fixed to extension frame 600 via fasteners such as screws so that the damper plate assembly 2500 is pivotable about the radial damper axle 2426.
In nominal operation, the retraction cam 1000 rotates or pivots about the mounting point 2105 in a manner consistent with retraction of the leg rest extension frame 600. While doing so, the cam 1000 interacts with the swing arm assembly 2200. The interaction with the swing arm assembly 2200 is provided by the groove follower 2220 which causes the lever arm 2260 to raise in a counterclockwise direction allowing for no interaction with the damper plate 2520. In other words, nominal operation results in the swing arm 2200 not interacting with the damper system 2900. The damper system 2900 is only configured to engage when the leg rest 200 is stationary and in a fully extended configuration during some stage of deployment. If the leg rest pad 700 is forcibly retracted by, e.g., the passenger's/user's legs, the damper system 2900 engages and provides resistance to increase the stability of the leg rest pad 700.
When the leg rest 200 is moved from a stowed position to a deployed position tension is applied to the retraction cable 920 by the extension mechanism (e.g., spring between the mounting fixture 500 and extension frame 600) moving the extension frame 600 relative to (i.e., away from) the mounting fixture 500. The cable 920 pulls at the retraction cam 1000 rotating the cam 1000 such that the torsion spring leg 1640 compresses against the static torsion spring catch 2800 of the mounting plate 2100. Accordingly, the torsion spring 1600 builds up potential energy.
When the leg rest 200 is moved from the deployed position to a stowed position, tension in the retraction cable 920 is increased due to the interaction of the cam stud 1190 and the nose of linkage 430 which causes the retraction cam 1000 to rotate about pivoting point 2105. The torsion spring 1600 is secured to the cam body 1100 such that contact between the cam stud 1190 and linkage nose 431 is preserved and such that additional tension can be provided when slack in cable 920 is experienced.
Contact between the cam stud 1190 and linkage nose 431 ensures consistent and smooth functionality of the leg rest 200 during operation and the slack is removed through rotation of the retraction cam 1000 (and in particular through rotation of the cable sheave groove 1210). The torsion spring 1600 may be unable to apply sufficient torque to fully remove all slack from the retraction cable 920 (due to limited availability of space in the retraction cam 1000). To increase the torque capabilities (and to remove the slack) a tensioning spring 1700 may be added to the retraction cam 1000 to address this issue.
The tensioning spring 1700 is an additional spring secured to the cam body 1100 and the spur body 1200. The tensioning spring 1700 supplies potential energy allowing for the effective arclength of the retraction cam 1000 to increase/decrease depending on tension in the retraction cable 920. Automatic adjustment of the retraction cam's 1000 effective arclength results in an increased capability to provide tensioning to the retraction cable 920. This is possible because the spur body 1200 is able to rotate or pivot relative the cam body 1100 with motion being driven by the tensioning spring 1700.
During rotation of the spur body 1200 moves or rotates relative to the cam body 1100. The bearings 1400, 1500 provide support and lower friction for the cam body 1100 and the spur body 1200.
The intermediate bearing 1400 (fixed to the first main surface 1104 of the cam body 1100) interacts with the intermediate bearing channel 1270 (fixed to the second main surface 1208 of the spur body 1200). The channel 1270 is designed to easily slide against while the spur body 1200 moves against the cam body 1100. The channel 1270 is designed with a depth slightly smaller than the thickness of the intermediate bearing 1400 to prevent metal-to-metal contact of the bodies 1100, 1200 from occurring.
The intermediate bearing 1400 is designed to act as both a thrust washer and a bushing that reduces friction between rotating components 1100, 1200. The bearing 1400 can reduce friction when both bodies 1100, 1200 are compressed against each other. An outer edge of the bearing 1400 is intended to slide against the intermediate bearing channel 1270 walls to reduce the radial force experienced at the pivot axle 1170. This interaction between the outer edge of the bearing 1400 and the channel 1270 reduces friction and prevents metal-to-metal contact during rotation.
The rotation bearing 1500 complements the intermediate bearing 1400. The rotation bearing 1500 provides additional support by keeping the rotation stabilizing flange 1140 aligned with the rotation stabilizing flange channel 1260 formed by the post 1250 and the overhang of the rotation bearing 1500. During operation the rotation stabilizing flange 1140 moves in the flange channel 1260 back and forth, and the flange 1140 and the channel 1260 may be pressed against each other. Moreover, the rotation bearing 1500 and the intermediate bearing 1400 may be pressed against each other so that the surfaces contact each other and rotate in a low friction movement.
The tensioning spring 1700 may push the spur body 1200 pivotally away from the cam body 1100 when the leg rest 200 moves from a stowed position to a deployed position (eventually reaching an extended state). In various embodiments the spur body 1200 can pivot up to 45 degrees away from the cam body 1100. The maximum movement may be set by the rotation hard limit slot 1150. The tensioning spring 1700 pulls the spur body 1200 pivotally towards the cam body 1100 when the leg rest 200 moves from the deployed position towards the stowed position (eventually reaching a collapsed state). The tensioning spring 1700 is secured to the cam body 1100 and the spur body 1200 such that the spur body 1200 is moved away from the cam body 1100 when the tensioning spring 1700 moves from an extended length to a shorter length. In other embodiments the tensioning spring 1700 operates the opposite way. In the collapsed configuration of the leg rest 200 the reset bumper 1230 may contact the static torsion spring catch 2800.
The system describes a mechanism for disengaging a retraction damping system when the leg rest 200 moves from an extended to a stowed position. The system comprises three key components: 1. A retraction cam 1000/cam body 1100 with a specialized damper groove profile 1180 containing three distinct sections. A lower rotational limit section 1181, a groove profile ramp section 1183 and an upper rotational limit section 1185. 2. A swing arm assembly 2200 featuring a long nose plunger 2222 arranged and a lever arm 2260. 3. A damper plate assembly 2500 with a hook feature 2522.
As described earlier, the swing arm assembly 2200 is pivotally fixed to the mounting plate 2100 and the support plate 2300 via the swing arm shaft 2240. The cable 920 is arranged in the cable sheave groove 1210 of the spur body 1200 of the retraction cam 1000. The damper mount housing assembly 2400 is fixed to the extension frame 600 so that it sandwiches the rotational damper plate assembly 2500 in between.
When the leg rest 200 is in the extended or deployed position, the lever arm 2260 is engaged with the hook catching feature 2522. This helps to maintain the leg rest 200 in its deployed position. When the leg rest 200 is manually pushed back to a stowed position, this engagement provides a resistance in moving the extension frame 600 towards the mounting fixture 500. When the leg rest moved by the motor 150 from the extended position to the stowed position the extension frame 600 moves against the mounting fixture 500 when (and only when, i.e., not before) the linkage nose 431 engages with the cam stud 1190 of the rotation cam 1000.
The disengagement process occurs as follows: 1. When the motor 150 initiates retraction, a cam stud 1190 of the retraction cam interacts with a linkage nose 431, causing the retraction cam 1000 to rotate clockwise. 2. As the cam body 1100 rotates, the long nose plunger 2222 interfaces with the damper groove profile 1180 sections sequentially. It starts at the lower rotational limit 1181, transitions through control groove ramp 1183 and reaches the upper rotational limit 1185. 3. This rotation of the cam body 1100 causes the swing arm assembly 2220 to pivot upward, disengaging the lever arm 2260 from the hook catching feature 2522 and maintaining this disengagement throughout the section 1185. The system remains disengaged until the cam body returns to its initial zero-degree position during extension.
The damper groove profile/section 1181 (lower rotational limit, region with large relative radius) interacts with the long nose plunger 2222 when the cam body 1100 has a relative angle of zero degrees (with respect to the mounting plate 2100). This region 1181 (only) interacts with the swing arm assembly 2200 when the extension frame 600 is extended with respect to the mounting fixture 500. The lever arm 2260 is engaged with the hook catching feature 2522. This engagement resists external forces that attempt to manually retract the leg rest extension frame 600 towards the mounting fixture 500.
The damper groove profile/section 1183 (ramp section, region with non-constant radius that connects the upper and lower rotational limit sections). This section 1183 interacts with long nose plunger 2222 as the cam body 1100 rotates from 0 degrees to 10 degrees (or 0 degrees to 15 degrees, or 0 degrees to 20 degrees). The clockwise rotation of cam body 1100 results in the swing arm assembly 2200 to pivot upwards in a counterclockwise direction. This results in disengagement between the damper plate assembly 2500 and the swing arm assembly 2200. In a reverse movement (moving the leg rest 200 from a stowed position to a deployed position, the cam body 1100 rotates counterclockwise resulting in the swing arm assembly 2200 to pivot downward in a clockwise direction. This eventually results in the engagement between the damper plate assembly 2500 and the swing arm assembly 2200.
The damper groove profile/section 1185 (upper rotational limit, region with small relative radius relative to the lower rotational limit). This section 1185 interacts with long nose plunger 2222 as the cam body 1100 rotates from 10 (or 15 or 20) to 105 degrees (or to a point other than 105 degrees such as 90 degrees or 120 degrees). The angles correspond to the rotation of the retraction cam 1000 to reach a fully retracted and stowed configuration (corresponding to the stowed position of the leg rest 200). The swing arm 2200 is fixed in an upwards orientation which prevents the damper plate assembly 2500 to be engaged. The retraction of the extension frame 600 relative to the mounting fixture 500 in this section 1185 occurs with no resistance from the system.
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.
This application is a Continuation-in-Part Application of U.S. application Ser. No. 18/238,365, filed on Aug. 25, 2023, which application is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 18238365 | Aug 2023 | US |
| Child | 19021391 | US |
