Title of the invention

Operating unit for setting a desired value for a level control of an adjustable support, level control of an adjustable support, and adjustable support

Technical field to which the invention relates

The present invention relates to an operating unit for setting a desired value for a level control of an adjustable support. Furthermore, the invention relates to a level control for an adjustable support comprising the operating unit and an adjustable support comprising the level control.

Indication of background art

Adjustable supports, such as a support frame of a vehicle seat, are generally known in the art and are employed, for example, to adjust the height of a vehicle seat to a user-specific height. Generally, these adjustable supports are provided with a linear actuator to adjust the height of the adjustable support according to a user's need. For adjusting and/or maintaining the user-specific height of the adjustable support, the use of a linear actuator valve as the level control is common practice. For example, the linear actuator valve communicates pneumatically with an air spring serving as the linear actuator and selectively controls the filling and the deflating of the air spring to adjust and/or maintain the height of the adjustable support.

In this regard, EP 2 217 810 Bl discloses a linear actuator valve adapted for position control and position adjustment of a linear actuator. The linear actuator valve comprises a valve housing and a valve slider movable within the valve housing. The position of the valve housing relative to the valve slider determines whether pneumatic pressure is supplied to or released from the linear actuator. When the valve slider is in a neutral position, pneumatic pressure is neither supplied to nor released from the linear actuator. If the valve slider moves in one direction with respect to the housing from the neutral position to a deflected position, for example, an outlet port of the linear actuator valve connected to an inlet port of the linear actuator is allowed to communicate with a pressurized air source and pressurized air is supplied to the linear actuator. If the valve slider moves from the neutral position in the other direction opposite to the one direction with respect to the housing, for example, the outlet port of the linear actuator valve is allowed to communicate with outside air and the pressurized air within the linear actuator is released to the outside.

The valve slider is coupled to a support member of the linear actuator valve. Thus, by adjusting the support member (which is described in detail below), it can be controlled whether pneumatic pressure is supplied to or released from the linear actuator. This allows position control and position adjustment of the adjustable support.

Figure 1 illustrates an adjustable support provided with an air spring L serving as the linear actuator and a level control constituted by the linear actuator valve. The adjustable support is exemplified as a scissor lift having an adjustable height H. A first end of the level control is connected to a first scissor member at a first fixing point and a second end of the level control is connected to a second scissor member at a second fixing point. A distance A between the first and the second fixing points corresponds to an overall length of the level control. The first and second fixing points are selected such that a change in the height H results in a change in the distance A. Thus, a specific height H of the adjustable support corresponds to a specific distance A (i.e., the overall length of the level control).

The support member of the level control is slidably connected to the valve housing. Thus, the length of the level control (distance A) can be changed by moving the support member relatively to the valve housing. As described above, the support member of the level control is coupled to the valve slider, that is, a distance HV described below is kept constant (the coupling is not illustrated in Figure 1). When the distance A changes, for example, by increasing or decreasing a load acting on the adjustable support, the support member is moved relatively to the valve housing. Thereby the valve slider is moved from the neutral position to the deflected position at which pneumatic pressure is supplied to or released from the linear actuator until the initial distance A is restored and the valve slider is in the neutral position again. This constitutes the function of maintaining a specific height H of the adjustable support (position control).

As mentioned above, the support member is coupled to the valve slider by means of a coupling mechanism (not shown) such that there is formed the distance HV between the support member and the end of the valve slider. The distance HV is adjustable by the coupling mechanism and a corresponding operating unit. Thus, by changing the distance HV, the overall length of the level control (distance A) can be changed. By means of this, the setting of a desired value (that is, distance HV) corresponding to a height H of the adjustable support is implemented. Specifically, when the desired value for the distance HV is changed by operating the operating unit, the valve slider is moved from the neutral position to the deflected position, at which pneumatic pressure is supplied to or released from the linear actuator until the distance A of the level control has changed by the same amount as the desired value HV has been changed and the valve slider is in the neutral position again. This constitutes the function of adjusting a user-specific height H of the adjustable support (position adjustment).

Conventional operating units for setting the desired value HV for the level control are disclosed, for example, in DE 10 2011 014 234 Al, WO 2020 074 684 Al, and DE 10 2006 022 767 B4.

The desired value HV is set via the operating unit having an adjusting mechanism, wherein the adjusting mechanism is able to latch into multiple positions whereby multiple values can be set as the desired value HV corresponding to different specific heights of the adjustable support. The preselected position of the adjusting mechanism is transmitted to the level control (for example, via a Bowden cable), where the corresponding desired value HV is set by the coupling mechanism. As a result, the level control controls the adjustable support to the corresponding height H.

The preselected position of the adjusting mechanism also provides a memory function, as the seat returns to the preset height after large deflections of the adjustable support (e.g., caused by impacts or increasing/decreasing the load acting on the adjustable support) or after a quick-down lowering, which is described in the following description.

When using the adjustable support as a support for a vehicle seat, the heightadjustment of the support, especially when used in commercial vehicles, usually has a quick-down lowering function to make it easier for the driver to get in and out of the vehicle. Conventionally, as shown in Figure 2, this is realized with a separate quick-down valve located between the air spring and the level control. This additional valve is operated with an additional quick-down operating unit.

When the quick-down valve is moved to a lowered position, the air spring is deflated (to R.1 in Figure 2) and the seat is lowered to the lower limit stop (minimum height of the adjustable support).

When the quick-down valve is returned to a driving position, the air spring is filled via the level control (from A to Z in Figure 2) and the seat returns to the preset height adjusted by the adjusting mechanism of the operating unit (memory function).

In order to make the overall structure of the adjustable support including the level control and providing the quick-down lowering function more cost-effective and simpler, it is considered to omit the separate quick-down valve and to implement the quick-down lowering function by the level control as it is schematically shown in Figure 3. Consequently, the control of the lowered position (seat position at minimum height) would have to be realized in the same way as the control of the driving position (seat position at user-specific height). This means that the control is carried out via the same adjusting mechanism of the operating unit, which sets the desired value HV for the level control. The lowered position corresponding to a seat position at minimum height thus corresponds to a lower limit position of the adjusting mechanism. However, this eliminates the memory function, as the adjusting mechanism must be readjusted from the lower limit position corresponding to the lowered position to the driving position corresponding to the previous seat position at the user-specific height. This means that the driver has to adjust the user-specific height with the adjusting mechanism again each time after a quick-down lowering has taken place. Thus, the operation of the adjustable support is not particularly comfortable for the user (i.e., the driver), and in particular the ease of use is less good compared to the structure having the separate quick-down valve.

Technical problem to be solved

In view of the above, it is the object of the present invention to provide an operating unit for setting a desired value for a level control of an adjustable support having excellent operating comfort.

Disclosure of invention

The object is achieved by an operating unit having the features of the independent claim 1. A level control according to the invention is subject-matter of claim 13. An adjustable support according to the invention is subject-matter of claim 14. Further advantageous developments are set out in the dependent claims.

According to the invention, the operating unit comprises a first operating element and a second operating element both operable by a user. The first operating element serves for adjusting a user-specific value corresponding to a user-specific height of the adjustable support. That is, the first operating element serves for the height-adjustment of the adjustable support. The second operating element selectively transmits the user-specific value adjusted by the first operating element or a minimum value corresponding to a minimum height of the adjustable support as the desired value to the level control.

As a result, the control of the lowered position of the adjustable support can be carried out via the same adjusting mechanism, which sets the desired value HV for the level control.

Furthermore, when the second operating element is switched, the desired value is set either to the minimum value or to the user-specific value adjusted by the first operating element. Therefore, readjusting the desired value to the userspecific value is not required.

As a result, the operating unit according to the present invention provides excellent operating comfort.

Further benefits and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments for carrying out the present invention with reference to the accompanying drawings.

Brief description of drawings

In the drawings:

Figure 1 is a schematic view of an adjustable support including a level control.

Figure 2 is a schematic diagram of a level control including a separate quick-down valve.

Figure 3 is a schematic diagram of a level control having an integrated quick-down function (without the quick down valve). Figures 4A, 4B, and 4C show different schematic views of an operating unit according to a first embodiment of the present invention in a state corresponding to a seat position at a user-specific height.

Figures 5A, 5B, and 5C show different schematic views of the operating unit according to the first embodiment in a state corresponding to a seat position at a lowered height.

Figure 6 shows sectionals views of the operating unit as indicated in Figures 4C and 5C.

Figure 7 shows the operating unit according to the first embodiment with an indicated path of a Bowden cable.

Figure 8 shows the operating unit according to the first embodiment including a compensation spring in a state corresponding to a seat position at the user-specific height.

Figure 9 shows the operating unit according to the first embodiment including the compensation spring in a state corresponding to a seat position at lowered height.

Figure 10 shows a bracket of the operating unit according to the first embodiment.

Figure 11 shows the operating unit according to the first embodiment in mirrored versions for left and right.

Figures 12A, 12B, and 12C are schematic views of the adjustable support at different heights.

Figures 13A, 13B, and 13C are schematic views of the level control showing states at different desired values HV.

Figure 14 is a schematic view of an operating unit according to a second embodiment of the present invention.

Figures 15A and 15B show the operating unit of Figure 14 in different operating states corresponding to seat positions at different user-specific heights.

Figures 16A and 16B are schematic views of the operating unit of Figure 14 in an operating state corresponding to the seat position at lowered height.

Description of at least one way of carrying out the invention In the following embodiments, the operating unit is exemplified as an operating unit serving for height-adjustment of a vehicle seat. The vehicle seat comprises an adjustable support in order to adjust the height of the seat to a user-specific height according to a user's need. However, the present invention is not limited to an operating unit serving for height-adjustment of vehicle seats but can be used for lifting devices and adjustable supports in general.

First embodiment

In the following, a first embodiment of the present invention is described with reference to figures 4 to 11.

The operating unit comprises a first operating element serving for the heightadjustment of the seat (adjustable support) and a second operating element serving for the quick-down lowering of the seat. According to the first embodiment, the first operating element is configured as a click-stop switch 1 and the second operating element is configured as a shift lever 2. The click-stop switch 1 and the shift lever 2 are pivotably arranged side by side in a bracket 3 so as to be movable in a first direction (i.e., downwards in Figure 6) and a second direction (i.e., upwards in Figure 6) opposite to the first direction upon an operation by the user (e.g., a driver of the vehicle).

Figures 4A to 4C show different schematic views of the operating unit in a state corresponding to a seat position, for example, at medium height as the userspecific height. The click-stop switch 1 and the shift lever 2 are at the same positions with respect to the first and second directions. That is, the shift lever 2 is in a driving position (a first position according to the claims).

Figures 5A to 5C show different schematic views of the operating unit in a state corresponding to a seat position at lowered height (a minimum height). That is, the shift lever 2 for the quick-down lowering is shifted down (that is, is shifted towards the first direction) to a lowered position (a second position according to the claims). Consequently, the seat is lowered to the minimum height of the adjustable support, which corresponds to the seat position at lowered height. However, the click-stop switch 1 is still at the position corresponding to the seat position at medium height. This constitutes the memory function of the operating unit. In order to return to the previous seat position (for example, the seat position at medium height), the shift lever 2 is shifted up (that is, towards the second direction) to the driving position, as depicted in Figures 4A to 4C. As a result, the seat returns to the seat position at medium height.

The shift lever 2 can be selectively shifted between the driving position (first position) and the lowered position (second position). The driving position corresponds to the seat position at the user-specific height adjusted by the clickstop switch 1, and the lowered position corresponds to the seat position at lowered height (the minimum height).

In the following, the configurations of the click-stop switch 1, the shift lever 2, the bracket 3, and their interaction as parts of the operating unit are described in detail.

Figure 6, section A-A, shows a sectional view of the operating unit along line A-A in Figure 4C, the operating unit being in a state corresponding to a seat position at user-specific height.

The click-stop switch 1 includes multiple latching lugs 11 into which a first spring hook 31 formed on the bracket 3 latches. The first spring hook 31 can be formed as an integral part of the bracket 3 (as illustrated) or can be formed as a separate member. By shifting the click-stop switch 1 in the first or second directions, the click-stop switch 1 is allowed to latch with any one of the multiple latching lugs 11, resulting in a changed position of the click-stop switch 1. Thereby, the click-stop switch 1 can be shifted to multiple positions corresponding to seat positions at different heights. Therefore, by operating the click-stop switch 1 in the first or second directions, the user can adjust the height of the seat to the desired user-specific height. Figure 6, section B-B, shows a sectional view of the operating unit along line B-B in Figure 4C, the operating unit being in a state corresponding to a seat position at user-specific height.

The shift lever 2 is connected via a Bowden cable 4 (indicated by a dashed line) to the level control in order to transmit a desired value HV to the level control (which will be described below). The shift lever 2 has a Bowden cable attachment 21 and a Bowden cable guide 22. The inner cable of the Bowden cable 4 for level controlling is attached to the shift lever 2 by the Bowden cable attachment 21. The inner cable is guided by the bracket 3 within a cable guide 35 (see Figure 7). The outer cable of the Bowden cable 4 is supported, for example, at an outer cable support 33 provided on the bracket 3. The level control exerts an urging force F, which is transmitted to the shift lever 2 via the Bowden cable 4. The urging force F exerted by the level control holds the shift lever 2 at the driving position, that is, a position, at which the shift lever 2 abuts on the click-stop switch 1. This is described in detail below.

Figure 6, section C-C, shows a sectional view of the operating unit along line C-C in Figure 4C, the operating unit being in a state corresponding to a seat position at user-specific height.

As can be seen from Figure 6, section C-C, the click-stop switch 1 comprises a stop cam 13 (a second abutment according to the claims) and the shift lever 2 comprises a stop cam 23. The stop cam 13 and the stop cam 23 are configured such that they abut against each other, when the position of the click-stop switch 1 corresponds to the position of the shift lever 2 with respect to the first and second directions (that is, the click-stop switch 1 and the shift lever 2 are in alignment). The urging force F transmitted via the Bowden cable causes the stop cam 23 of the shift lever 2 to be pressed against the stop cam 13 of the clickstop switch 1. Thus, when the shift lever 2 is at the driving position, the desired value HV transmitted from the shift lever 2 to the level control is determined by the position of the click-stop switch 1, which is adjustable by shifting the clickstop switch 1 in the first and second directions.

Figure 6, section D-D, shows a sectional view of the operating unit along line D- D in Figure 5C, the operating unit being in a state corresponding to a seat position at lowered height.

As can be seen from Figure 6, section D-D, the click-stop switch 1 of the operating unit in a state corresponding to a seat position at lowered height is still at the same position as in the state corresponding to a seat position at medium height.

Figure 6, section E-E, shows a sectional view of the operating unit along line E-E in Figure 5C, the operating unit being in a state corresponding to a seat position at lowered height.

As can be seen from Figure 6, section E-E, the shift lever 2 is shifted down to the lowered position. The shift lever 2 includes a latching cam 25, which latches with a second spring hook 32 of the bracket 3 and holds the shift lever 2 at the lowered position. The Bowden cable 4 (not shown) is thereby pulled in such a way that a minimum value HV3 (which will be described below) is established at the level control, which corresponds to the lowered height. As a result, the desired value HV set by the operating unit is the value HV3 (minimum value) corresponding to the minimum height of the adjustable support.

Figure 6, section F-F, shows a sectional view of the operating unit along line F-F in Figure 5C, the operating unit being in a state corresponding to a seat position at lowered height.

When the shift lever 2 is pressed down, another stop cam 24 of the shift lever 2 is pressed against an abutment 34 (corresponding to the first abutment according to the claims) of the bracket 3 in order to securely stop the movement of the shift lever 2 at the lowered position. When the shift lever 2 is shifted up again to the driving position in order to return to the previous seat position, the shift lever 2 is stopped by the stop cam 23 abutting on the stop cam 13 of the click-stop switch 1 and is thus at the same position as in the state shown in Figures 4A to 4C (a state corresponding to a seat position at medium height). As a result, the desired value HV transmitted from the shift lever 2 to the level control is again determined by the position of the click-stop switch 1, which is still the same.

The urging force F exerted by the Bowden cable 4 acts on the latching lugs 11 of the click-stop switch 1 and the latching cam 25 of the shift lever 2. Therefore, the first and second spring hooks 31 and 32 of the bracket 3 have to be designed sufficiently strong so as to be able to hold the click-stop switch 1 and the shift lever 2 securely at the various positions. This in turn has an impact on the operating forces required for operating the click-stop switch 1 and the shift lever 2, which become correspondingly high.

As shown in Figures 8 and 9, in order to reduce the operating forces, an additional compensating spring 5 may be installed between the bracket 3 and the shift lever 2 to counteract and partially compensate the urging force F exerted by the Bowden cable 4 (not shown). The spring force of the compensation spring 5 along with the lever arm DI or D2 generates a torque acting on the shift lever 2. The attachment points can be selected such that the lever arm DI is smaller when the spring force is high (see Figure 8) than the lever arm D2 when the spring force is low (see Figure 9). This allows the torque to remain approximately constant, regardless of the position of the shift lever 2. The torque generated by the compensating spring 5 counteracts the torque generated by the urging force F of the Bowden cable 4 (see Figure 7) and thus allows lower latching forces and thus lower operating forces.

Vehicle seats usually come in a left and a right version, where the elements are arranged in mirror image positions. For this purpose, the click-stop switch 1 and the shift lever 2 are both designed symmetrically (see, for example, Figures 4B and 5B). As shown in Figure 10, the bracket 3 has two identical accommodation geometries into which both the click-stop switch 1 and the shift lever 2 fit. The first and second spring hooks 31 and 32 are identical and the cable guide 35 is mirror- inverted in both directions.

This makes it possible to mount the same components in mirror image positions and to create a left-hand and a right-hand version as shown in Figure 11.

In the following, the use of the operating unit for operating the adjustable support having a quick-down lowering function will be described with reference to Figures 12 and 13.

Figures 12A to 12C show the adjustable support in different states. Figures 13A to 13C show the level control in different states corresponding to the states of the adjustable support shown in Figures 12A to 12C.

Figure 12A shows a state of the adjustable support corresponding to a relatively high seat position at a height Hl. For the seat position at height Hl the desired value HV1 is set by the operating unit (adjusted by correspondingly shifting the click-stop switch 1, for example, in the second direction). By changing the value HV to the desired value HV1, the valve slider is moved out of the neutral position to a position allowing pressurized air to be supplied to the air spring. The level control allows the filling of the air spring until the valve slider returns to the neutral position. As shown in Figure 13A, the level control then has a length Al corresponding to the height Hl of the adjustable support.

Figure 12B shows a state of the adjustable support corresponding to a relatively low seat position at a height H2 (H2<H1). For the seat position at height H2 the desired value HV2 (HV2<HV1) is set by the operating unit (by shifting the clickstop switch 1, for example, in the first direction). By changing the desired value from HV1 to HV2, the valve slider is moved out of the neutral position to a position allowing pressurized air to be released from the air spring. The level control allows the deflating of the air spring until the valve slider returns to the neutral position. As shown in Figure 13B, the level control then has a length A2 (A2<A1) corresponding to the height H2 of the adjustable support.

Figure 12C shows a state of the adjustable support corresponding to a lowered seat position at a height H3 (H3<H2). For the lowered seat position at height H3 the desired value HV3 (HV3<HV2) is set by the operating unit (by shifting the shift lever 2 from the driving position to the lowered position). By changing the desired value to HV3, the valve slider is moved out of the neutral position to a position allowing pressurized air to be released from the air spring. The level control allows the deflating of the air spring until the adjustable support abuts on a lower limit stop of the adjustable support. As shown in Figure 13C, the valve slider is then still in the deflected position allowing the deflating of the air spring and the level control has a length A3 (A3<A2) corresponding to the height H3 of the adjustable support.

Second embodiment

A second embodiment of the operating unit is described below with reference to Figures 14 to 16.

The second embodiment differs from the first embodiment in that the first operating element serving for the height-adjustment of the seat (adjustable support) and the second operating element serving for the quick-down lowering of the seat are arranged spatially separated.

Similar to the first embodiment, the first operating element is configured as a click-stop switch 101 and the second operating element is configured as a shift lever 102. However, according to the second embodiment, the click-stop switch 101 and the shift lever 102 are arranged in separate brackets 103 (see Figure 14). The interaction between the click-stop switch 101 and the shift lever 102 is established via an additional mechanism. This mechanism can be implemented by a drawbar, a cable control, or a Bowden cable. The click-stop switch 101 for the height-adjustment is rotatably supported by a first bracket 103. As in the first embodiment, the click-stop switch 101 is provided with latching lugs 111 into which a first spring hook 131 of the first bracket 103 latches and predetermines the seat positions at various heights (user-specific height). The click-stop switch 101 comprises a first actuating lever 113. An inner cable 141 of a Bowden cable 104 connecting the operating unit with the level control is hooked to the first actuating lever 113 by a first cable head 143 fixed to the inner cable 141. Therefore, the click-stop switch 101 acts on the Bowden cable via the first actuating lever 113 and the desired value HV of the level control can be adjusted by operating the click-stop switch 101. The first bracket 103 includes an outer cable support 133 for supporting an outer cable 142 of the Bowden cable 104.

The shift lever 102 for the quick-down lowering is rotatably supported by a second bracket 103. Preferably, the second bracket 103 for the shift lever 102 and the first bracket 103 for the click-stop switch 101 are identical in design. This reduces the number of different components for the operating unit. The distance and the positioning of the first and second brackets 103 to each other are basically arbitrary.

For the sake of simplicity, an embodiment with a straight Bowden cable 104 is illustrated in the drawings. Similar to the first embodiment, the shift lever 102 for the quick-down lowering has two shift positions between which it can be switched. A first position, that is, a driving position, corresponds to a seat position at the user-specific height and a second position, that is, a lowered position, corresponds to a seat position at lowered height.

The shift lever 102 comprises a second actuating lever 121 for connecting with and acting on the mechanism establishing the interaction between the shift lever 102 and the click-stop switch 101. According to the second embodiment, the mechanism is constituted by an extension of the inner cable 141 and a second cable head 144. The extension of the inner cable 141 is hooked to the second actuating lever 121 by the second cable head 144. Figures 15A and 15B show schematic views of the operating unit in a state corresponding to a seat position at user-specific heights. The shift lever 102 is in the driving position. Figure 15A shows a state in which the click-stop switch 101 is positioned so as to correspond to a relatively high seat position and Figure 15B shows a state in which the click-stop switch 101 is positioned so as to correspond to a relatively low seat position.

When the operating unit is in a state corresponding to a seat position at the user-specific height, the shift lever 102 is at the driving position in which the second cable head 144 is not in contact with the second actuating lever 121. Consequently, no force is applied to the extension of the inner cable 141 and the extension of the inner cable 141 is without function in this state. The shift lever 102 abuts with a stop cam 123 formed on the shift lever 102 against a stop cam 135 formed on the second bracket 103. The shift lever 102 is held in this position by a second spring hook 132 formed on the second bracket 103, the second spring hook 132 latching with a latching cam 126 formed on the shift lever 102.

Figures 16A and 16B show schematic views of the operating unit in a state corresponding to a seat position at lowered height. The shift lever 102 is in the lowered position. Figure 16A shows a state in which the click-stop switch 101 is positioned so as to correspond to a relatively high seat position and Figure 16B shows a state in which the click-stop switch 101 is positioned so as to correspond to a relatively low seat position.

When the shift lever 102 is shifted to the lowered position corresponding to the seat position at the lowered height, a stop cam 124 formed on the shift lever 102 abuts on a stop cam 134 formed on the second bracket 103. The shift lever 102 is held in this position by the second spring hook 132 latching with a latching cam 125 formed on the shift lever 102. The second cable head 144 is pulled along by the second actuating lever 121 and the extension of the inner cable 141 is activated. As a result, the first cable head 143 lifts off the first actuating lever 113 of the click-stop switch 101. However, the click-stop switch 101 remains in its preset position (corresponding to the user-specific height) held by the first spring hook 131, therefore providing the memory function. In this state, the desired value HV3 is set for the level control via the Bowden cable 104 and the seat is lowered to the lowered height.

When the shift lever 102 is returned to the driving position (as shown in Figures 15A and 15B), the first cable head 143 again contacts the first actuating lever 113 of the click-stop switch 101 and the seat returns to the position at the userspecific height adjusted by the click-stop switch 101.

According to the second embodiment, it is also possible to provide a compensation spring, for example, at the end of the extension of the inner cable 141 at the second cable head 144.

A left and right design can be created by making the click-stop switch 101, the shift lever 102, and the first and second brackets 103 mirror symmetrical to a horizontal central plane.

The above description is not exhaustive, and the present invention is not limited to the above embodiments. The skilled person will recognize that various modifications and combinations of the above embodiments are possible within the scope of the invention. Accordingly, the scope of the invention should be determined from the accompanying claims.