Operating unit

Abstract

An operating unit comprising a housing (2) for at least partially accommodating a control adapter (3) comprising a lever adapter (4) is provided. The control adapter (3) is pivotally mounted relative to the housing (2) around a rotational axis (6), the control adapter being pivotable from an initial position in a first pivoting direction and in a second pivoting direction that is opposite to the first pivoting direction. The operating unit further comprises restoring means (7) for restoring the control adapter (3) to the initial position, wherein the restoring means (7) comprises at least a first and a second torsion spring (8) each comprising a first end (9) and a second end (10). The first torsion spring (8) is coupled at its first end (9) to the control adapter (3) and at its second end to the housing (2) at least during a tensioning of the first torsion spring. The second torsion spring (8) is coupled at its first end (9) to the control adapter (3) and at its second end to the housing (2) at least during a tensioning of the second torsion spring.

Description

[0001] Operating unit

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to an operating unit comprising a housing for at least partially accommodating a control adapter and restoring means, wherein the restoring means comprise at least two torsion springs.

[0004] BACKGROUND

[0005] Nowadays, electric systems are used to control machines such as agricultural or construction vehicles, e.g. excavators. To facilitate user feedback in such systems that are nearly free of sensible mechanical resistance, which has typically given rise to user feedback, special components need to be integrated. These create an artificial mechanical resistance that is noticeable by a machine user. Especially in agricultural vehicles, these feedback forces need to be stronger than the vibrations and jerking that are omnipresent in the typical use environment of these vehicles to be sensible by the user.

[0006] Operating levers are widely used in agricultural vehicles. They are commonly controlled by an operating unit. The configuration of the operating unit amongst others gives rise to an opposing force enabling user feedback in an electric steering system.

[0007] In use, the operating lever is pivoted by a user. The operating lever is connected to the operating unit via a control adapter, which transfers the motion of the operating lever to the operating unit. For restoring or repositioning the operating lever and the control adapter in their neutral or starting position (e.g. initial position), restoring means are provided, commonly in form of a single torsion spring. The mentioned operating lever is commonly moved in at least two opposite directions and has to undergo many motion cycles. Therefore, the torsion spring has to be designed to withstand these numerous load-cycles through a long lifetime and maintain a backlash-free re-positioning. This requirement leads to a rather large torsion spring that disadvantageously requires a large space within a housing of the operating unit. SUMMARY

[0008] Thus, there is a need to provide an improved operating unit, in particular an operating unit having reduced space requirements. It is further desirable to provide an operating unit providing an effective and backlash-free restoring of the operating unit’s operating lever.

[0009] According to an embodiment of the invention, an operating unit comprising a housing for at least partially accommodating a control adapter comprising a lever adapter is provided. The control adapter is pivotally mounted relative to the housing around a rotational axis. Furthermore, the control adapter is pivotable from an initial position in a first pivoting direction and in a second pivoting direction that is opposite to the first pivoting direction. The operating unit comprises restoring means for restoring the control adapter to the initial position (e.g. by applying a respective restoring torque). The restoring means comprises at least a first and a second torsion spring each comprising a first end and a second end.

[0010] Optionally, the first torsion spring is coupled at its first end to the control adapter and at its second end to the housing at least during a tensioning of the first torsion spring (e.g. to generate a restoring torque), the coupling being configured such that when the control adapter is pivoted from the initial position in the first pivoting direction, the first torsion spring is tensioned to provide a restoring torque and when the control adapter is pivoted from the initial position in the second pivoting direction, the first torsion spring does not provide a restoring torque.

[0011] Further optionally, the second torsion spring is coupled at its first end to the control adapter and at its second end to the housing at least during a tensioning of the second torsion spring (e.g. to generate a restoring torque), the coupling being configured such that when the control adapter is pivoted from the initial position in the first pivoting direction, the second torsion spring does not provide a restoring torque, and when the control adapter is pivoted from the initial position in the second pivoting direction, the second torsion spring is tensioned to provide a restoring torque.

[0012] As the first torsion spring may only provide a restoring torque when the control adapter is pivoted from the initial position in the first pivoting direction and the second torsion spring may only provide a restoring torque when the control adapter is moved in the second pivoting direction, the wear of the respective torsion spring may be reduced significantly.

[0013] Due to the wear that occurs over the life cycle of the torsion spring, the play between the first end of the torsion spring and the coupling to the control adapter also increases. This may mean that a center play, which may be considered as a quality feature of the control adapter increases over time. By using two torsion springs each providing a restoring torque only in one pivoting direction of the operating unit, the torsion spring is only deflected in one direction. As a result, this center play can be avoided for a longer period of time, especially compared to the case in which a single torsion spring is used. In addition, since each torsion spring needs to provide restoring torque only in one direction, and due to the reduced wear on the torsion springs, torsion springs comprising a more compact design may be employed in the operating unit. Thus, the installation space required for the springs may be reduced. As a result, a more compact and cost- effective operating unit may be provided. As the restoring torque acts towards the initial position, the control adapter may be driven towards the initial position so that the user of the operating unit may receive haptic feedback that the control adapter is pivoted away from the initial position. By means of the restoring torque, the control adapter may further move from a pivoted position into the initial position without an application of force by the user to the control adapter.

[0014] As the wear of the restoring means may be reduced significantly by using two torsion springs, the restoring torque may remain constant over a longer period of time. As a result, it may be possible to safely drive the control adapter to the initial position for a longer period of time. In addition, the user may have to overcome the restoring torque to pivot the control adapter before he / she is able operate a machine. As the wear on the restoring means is reduced, the level of the restoring torque that has to be overcome in order to operate the machine may be maintained for a longer period of time, so that an unintentional pivoting of the control adapter may be avoided.

[0015] The restoring means, in particular the coupling of the torsion springs to the control adapter and the housing, may be configured such that the pivoting of the control adapter in the first pivoting direction is restored by a different torsion spring of the first and second torsion springs than the pivoting of the control adapter in the second pivoting direction. The coupling to the control adapter or to the housing may be a direct or indirect coupling. The coupling may not be permanent but may be present in some operational states of the operating unit and may be released in other operational states of the operating unit. For example, during pivoting of the control adapter in the direction in which the respective torsion spring is not tensioned, the respective torsion spring may be disengaged (or de-coupled) from the control adapter (or from the housing, depending on the configuration). Preferably, in the initial position of the control adapter, the first ends of both torsion springs may be coupled to the control adapter, and the second ends of both torsion springs may be coupled to the housing. The coupling of one end of each torsion spring may be disengaged from the control adapter or the housing when the control adapter is pivoted in the direction in which the respective torsion spring does not provide the restoring torque, e.g. is not tensioned.

[0016] In an embodiment, the first ends are pivotally mounted relative to the housing and the second ends are statically mounted relative to the housing. The second ends of the at least two torsion springs may be firmed up to the housing (they may be fixedly mounted with respect to the housing), so that the first end is relatively moved to the second end during the pivoting motion of the operating lever and hence the control adapter when the spring is tensioned. Each torsion spring of the embodiment may therefore substantially remain in its position during every movement / displacement of the control adapter. Only the first end of each torsion spring may be partly taken along with the motion of the lever adapter in one pivoting direction. The required space needed for accommodating the torsion springs can thus be reduced advantageously.

[0017] In an embodiment, the at least first and second torsion springs have an initial state in the initial position of the control adapter, wherein when the control adapter is pivoted from the initial position in the second pivoting direction, the first torsion spring remains in its initial state, and when the control adapter is pivoted from the initial position in the first pivoting direction, the second torsion spring remains in its initial state. Thus, the respective first or second torsion spring is only tensioned in one of the pivoting directions of the control adapter, respectively. This may decrease the wear of the first and second torsion springs significantly, in particular when compared to solutions in which only one spring is used to provide a restoring torque to the control adapter.

[0018] The initial state may correspond to a state in which the first and / or second torsion springs are pre-tensioned. The pre-tensioning may force the control adapter in opposite pivoting directions by the initial torques of the torsion springs, such that the control adapter is (firmly) secured in the initial position. The center play of the control adapter may be reduced significantly. As the restoring means are pre-tensioned, the force required by the user to pivot the control adapter may be increased. As a result, the user may perceive an improved feedback that the control adapter is moved from its initial position into a pivoting direction. Alternatively, it may be possible that the first and / or second torsion springs are not pre-tensioned in the initial state. Thereby, the wear on the restoring means may be decreased, as the springs are not held in a deflected state.

[0019] For example, only the first end of the first torsion spring may be taken along with the motion of the lever adapter in the first pivoting direction to tension the first torsion spring and only the second end of the second torsion spring may be taken along with the motion of the lever adapter in the second pivoting direction to tension the second torsion spring. The first end of the second spring may thus not be taken along when pivoting in the first pivoting direction, and the first end of the first spring may not be taken along when pivoting in the second pivoting direction. An efficient way to tension only one spring in each pivoting direction may thus be provided.

[0020] In an embodiment, the operating unit further comprises a stop for each of the first and second torsion springs, the stop being configured to provide a rest for the first end or the second end of the respective torsion spring. The stop is configured to stay in contact with the respective end of the torsion spring (e.g. to take along the respective end) when the respective torsion spring is tensioned during pivoting of the control adapter and is configured to allow the stop to move away from the respective end of the torsion spring when the respective torsion spring is not tensioned (e.g. stays in its initial position) during pivoting of the control adapter. Such stop may provide a simple configuration that allows tensioning of the spring in only one pivoting direction. The stop for each of the first and second torsion springs may apply a force to the first end or the second end of the first and second torsion springs, respectively, during tensioning of the spring.

[0021] The respective other end of the respective torsion spring may be statically mounted relative to the housing or to the control adapter, respectively. For example, the second end of each torsion spring may be held (directly) by the housing.

[0022] In an embodiment, the control adapter comprises at least one adapter stop to rest each first end of the restoring means there against and / or the housing comprises at least one housing stop to rest each second end of the restoring means there against. The above- mentioned stop may be the adapter stop. With respect to the adapter stop and the housing stop, the control adapter and the housing may be connected indirectly through the restoring means. Preferably, the adapter stop und the housing stop are configured in such a way that no further components are needed for resting the first and second ends there against. For that, the second end may be positively coupled or connected to the housing stop and / or the first end may be positively coupled or connected to the adapter stop.

[0023] The housing provides preferably two housing stops, which are positioned diametrically opposite to each other and the control adapter and the restoring means are positioned in between. The second ends of the at least two torsion springs may be firmed up to (e.g. fixedly mounted to or held by) the housing stop, so that the first end may be moved relatively to the second end during the pivoting motion of the operating lever and hence the control adapter. By using two housing stops, the torsion springs can be identical, differing only in the mounting orientation (one torsion spring may be rotated 180° along a longitudinal axis of the lever adapter and mounted this way).

[0024] The adapter stop may be designed to take at least one torsion spring (e.g. the first end of the first torsion spring) along the lever adapter while it is deflected in the first pivoting direction and to take at least one other torsion spring (e.g. the first end of the second torsion spring) along the lever adapter while it is deflected in the second pivoting direction.

[0025] Taking along the end of the respective torsion spring may comprise that the end of the respective torsion spring is moved relative to the housing. This may for example be achieved by moving the end of the respective torsion spring along a circular trajectory about the rotational axis along which the stop, e.g. the adapter stop, moves when the control adapter is pivoted.

[0026] While in some embodiments, the housing stop may maintain a position of the second spring end of the respective spring during pivoting of the control adapter (in either direction), it may in other embodiments allow the second spring end of the respective torsion spring to move when the spring is not being tensioned, i.e. when it remains in the initial state. In this case, the first end may be fixedly coupled to the control adapter so as to move with the control adapter in both pivoting directions.

[0027] Each torsion spring, which is not taken along the lever adapter during a pivoting motion in the first or second pivoting direction, may remain substantially motionless at its initial position (i.e. in its initial state). This may be achieved by resting the first end additionally on a security stop, which may be attached to the housing. The security stop secures (i.e. retains) the restoring means (in particular the first and second torsion springs) in its initial position and saves an initial torque within the at least two torsion springs. This is even the case during a motion of the control adapter in which the respective torsion spring does not rest against the control adapter. In other words, for a given pivoting direction, the first end of the torsion spring that is not taken along rests against the security stop so that it maintains its (pre-)tension while the adapter stop moves away from the first end of the torsion spring.

[0028] In an exemplary embodiment, the operating unit comprises a security stop for each torsion spring, wherein the security stop is configured and arranged to retain the respective torsion spring in the initial state by engaging an end of the respective torsion spring during the pivoting of the control adapter in the pivoting direction in which no restoring torque is applied by the respective torsion spring. The security stop may further be configured to allow the respective end of the respective torsion spring to move away from the security stop when the respective torsion spring is tensioned during pivoting of the control adapter.

[0029] For example, in one pivoting direction of the control adapter, the first end stays engaged with the security stop. In the other pivoting direction of the control adapter, the (adapter) stop takes along the first end of the torsion spring and thereby disengages the first end of the torsion spring from the security stop.

[0030] By incorporating the security stop, the respective torsion spring that is not applying a restoring torque may be securely retained in the initial state by the security stop while still ensuring that the torsion spring can be moved away from the security stop when the torsion spring is tensioned. The security stop may also ensure that the first (second) torsion spring cannot be deflected in the second (first) pivoting direction beyond the initial position. Thus, a deflection of the respective torsion spring into an unintended pivoting direction may be avoided.

[0031] In an embodiment, in the initial position of the control adapter, an end of the respective torsion spring rests against the security stop to pre-tension the respective torsion spring.

[0032] Such configuration may further ensure that the central play at the initial position of the control adapter does not increase over time. Wear generally occurs at the first end of the spring at which it abuts the adapter stop and the security stop and / or at the respective stops. Thus, if wear occurs, the position of the first end of the spring changes towards the adapter stop and security stop, in particular in view of the pre-tension. The first ends of both springs will thus always firmly rest against the adapter stop, thereby firmly centering the control adapter in the initial position and avoiding the occurrence of any center play in this position. If the first end of the spring or the security stop surface becomes worn out, the play in the initial position may even be reduced. Thus, through this arrangement, a ‘self-healing’ effect between these components may be realized and the wear that occurs during operation may not lead to any further center play of the operating unit, e.g. of a lever of a respective joystick.

[0033] In an embodiment, the security stop is coupled to the housing and is stationary with respect to the housing. For example, the security stop may form a part of an element that is mounted to the housing, thus allowing a space-efficient integration into the operating unit. Such an element mounted to the housing may comprise a cover part or the like. In the embodiment in which the first end is fixedly mounted to the control adapter and the second end is allowed to move with respect to the housing when the respective torsion spring is not tensioned during pivoting of the control adapter, the security stop may be provided on the control adapter and may move with the control adapter.

[0034] In an embodiment, the adapter stop for the first torsion spring and the adapter stop for the second torsion spring are provided as extensions that extend from the control adapter in opposite directions, preferably in a direction parallel to the rotational axis. Thus, a more compact integration of the adapter stop into the setup may be achieved, also by reducing the number of components. The arrangement may also ensure that the tolerances occurring in the operating unit, e.g. between the restoring means and the control adapter, may be adjusted more easily, as the contact points of the torsion springs may be adjusted independently, and each may only need to be adjusted for the contact point with the adapter stop in one direction.

[0035] In an embodiment, the adapter stop for the first torsion spring and the adapter stop for the second torsion spring are positioned on a remote end of the lever adapter opposite to an end of the lever adapter at which a handle is to be provided on the operating unit. By positioning the restoring means on the opposite side of the lever adapter, the leverage acting on the lever adapter may be increased compared to the positioning of the restoring means on the lever side. Consequently, it may be possible to generate the same restoring torque with a smaller force acting on the stop, thus reducing wear.

[0036] In an embodiment, the adapter stop for the first torsion spring and the adapter stop for the second torsion spring each comprise a groove configured to receive the first end of the respective torsion spring, the groove being configured to allow the first end of the torsion spring to engage and disengage the adapter stop. The adapter stop may thus take along the first end of the respective spring in one pivoting direction and may give free the first end of the respective spring in the other pivoting direction.

[0037] Further, a preferable development of the invention provides that at least two first ends of the restoring means rest on different adapter surfaces of the adapter stop, wherein the different adapter surfaces oppose each other. Every motion of the control adapter is preferably restored by a different torsion spring. Also more than one torsion spring can restore the control adapter to its initial position, while such a group of torsion springs rest on the identical adapter surface. By opposing the adapter surfaces to each other, the control adapter is reliably restored after a deflection in two opposing pivot directions. Thus, only a few of the restoring means are used while deflecting the control adapter. The load-cycles of each torsion spring are thus halved, leading to the advantage that the torsion spring can be designed smaller, thereby reducing the required space for mounting.

[0038] As an example, the adapter surfaces may be provided by a bottom of the grooves. As a result, the incorporation of the adapter surfaces on the bottom of grooves may allow a more compact setup with a reduced number of required components. The grooves may be arranged opposite each other, e.g. may open in opposite directions.

[0039] During use, deformations on the adapter surfaces and / or the first ends (e.g. due to wear) lead to the adapter surfaces getting a substantially concave shape. Due to resting of the torsion springs on the opposite adapter surfaces, a tolerance of the initial position will be improved, since the initial torques of the torsion springs affect against each other additionally to a stop. Thus, a backlash-free re-positioning / restoring may be provided during the whole lifetime of the operating unit. Both of the torsion springs, which each rest against opposite adapter surfaces, force the lever adapter in opposite pivoting directions by the initial torques of the torsion springs even when a deformation on the adapter surface and / or of the first ends appear. While this effect appears, the lever adapter is held in its initial position. Due to the deformation, a smaller tolerance or space between the first ends and the respective adapter surfaces appears and the hold of the lever adapter in its initial position even becomes better. This circumstance is defined as self-healing effect. As mentioned above, the adapter stop preferably has two grooves that are opposed to each other, so that the first ends of the at least two torsion springs each are insertable in the grooves of the adapter stop to provide a reliable rest of the first ends on the adapter surfaces. The adapter surfaces are preferably formed by the bottom surfaces of the grooves.

[0040] In an embodiment, the control adapter comprises a substantially cylindrical bearing seat, wherein the rotational axis is a longitudinal axis of the bearing seat.

[0041] In an embodiment, the first ends of the first and second torsion springs rest against the control adapter and the second ends of the first and second torsion springs rest at least indirectly against the housing.

[0042] The housing and the control adapter are preferably connected through a control shaft, which is statically mounted within the housing. More preferably, at least two bearings connect the control shaft and the control adapter, wherein the bearings are mounted on an inner surface of the bearing seat, which is hollow cylindrical. By “substantially cylindrical” the present disclosure may understand the bearing seat has an outer partly cylindrical surface, which is interrupted by the lever adapter in its middle along a longitudinal axis of a sliding sleeve. Further, the inner shape of the bearing seat may provide at least one stop for mounting a bearing. Further, the present disclosure may understand by “substantially cylindrical” a cylindrical shape, which might have some deviations from the mathematical definition of cylindrical. Such deviations appear especially during the manufacturing process.

[0043] In a preferable manner, the operating unit having any of the configurations described herein may be mounted in a further outer housing, while the operating unit is relatively pivotally mounted in the outer housing along a pivoting axis, wherein the pivoting axis is perpendicularly orientated to the longitudinal axis, i.e. to the rotational axis. Thus, a user is able to pivot the operating lever, which transfers its motion through the control adapter to the operating unit, in any pivoting direction, since the control adapter can be pivoted by itself and / or relatively by the pivoting motion of the housing. Between the housing and the outer housing, additional restoring means may be accommodated to restore the housing in its initial position, when the operating lever is released by the user. These additional restoring means may correspond to the restoring means partly accommodated in the housing. The additional restoring means may be provided by at least two further torsion springs each comprising a first end and a second end, wherein the first ends rest against the housing and the second ends rest against the outer housing. Such additional restoring means may have any of the configurations described herein with respect to the first mentioned restoring means.

[0044] According to an embodiment, the at least one adapter stop is positioned on an outer end of the lever adapter opposite the bearing seat and / or the at least one adapter stop is extended parallel to the longitudinal (i.e. to the rotational) axis. The control adapter may transfer the external force during use from the operating lever to the restoring means. The larger the distance between the adapter stop and the bearing seat, the smaller is the force that needs to be applied by the first end of the spring to the respective adapter stop on the control adapter. Since the bearing seat may be connected to a control shaft through at least two bearings, torque will not be transferred. Instead, the restoring means, which are mounted substantially coaxial to the bearing seat, will absorb the incoming torque for later repositioning the control adapter to its initial position at the moment the user releases it.

[0045] Additionally, the user gets some feedback on how much he has deflected the operating lever. The control adapter is pivotally mounted along the longitudinal axis. Therefore, a pivoting motion in two opposite directions is possible. If the adapter stop extends parallel to the longitudinal axis, i.e. to the rotation axis, the first end of the restoring means can easily rest against the adapter stop without the need of any additional components for maintaining the connection.

[0046] An embodiment provides that the at least two torsion springs have the same or a different spring ratio and / or a rectangular cross section. Advantageously, with respect to the individual use of the operating unit, the spring ratio is chosen to provide sufficient resistance to get the user a clear feedback and to reliably restore the control adapter towards the initial position. While different torsion springs interact as restoring means during different motions, the choice of the spring ratio also depends on whether a user needs to push or pull the operating lever and thus the control adapter. The first torsion spring absorbs a relative motion between the control adapter and the housing, while moving the control adapter in one first pivot direction and the second torsion spring absorbs another relative motion between the control adapter and the housing, while moving the control adapter in one second pivot direction, which opposes the first pivot direction. Thus, different torsion springs may be used to provide different restoring torques regarding to the pivot direction a user moves the control adapter.

[0047] The rectangular cross section of the torsion springs may provide surfaces by which especially the first and / or second end of the torsion spring can be rested to other components, e.g. on the adapter stop and / or on the security stop. Further, the manufacturing of torsion springs with such a shape is easy and cheap. The use of torsion springs with a circular cross section is also possible.

[0048] A spring angle, which is defined between the first end and the second end of each torsion spring, is preferably 90° in an initial position of the control adapter and not deflected. The spring angle is preferably between 110° and 120°, in particular 115° in a maximum deflected position of the control adapter. An initial torque of the torsion spring in the initial position of the control adapter is preferably between 0.5 Nm and 2 Nm, in particular between 0.75 Nm and 1.5 Nm. The maximum torque of the torsion spring in the maximum deflected position of the control adapter is preferably between 0.75 Nm and 3 Nm, in particular between 0.9 Nm and 2.5 Nm. For increasing the torque of the torsion spring, the cross-sectional shape of the torsion spring can be increased and / or the number of windings of the torsion spring can be increased.

[0049] According to a preferable embodiment, the restoring means are orientated axisymmetric, perpendicular to the lever adapter. Torsion springs are able to receive a generated force during a rotational motion. Preferably, the restoring means of the at least two torsion springs (e.g., coils of the helical torsion springs) are substantially coaxially mounted to the bearing seat. For example, the at least two torsion springs may have a hollow cylindrical shape and the first end and second end may extend from the cylindrical shape. The lever adapter may be perpendicularly orientated to the rotational axis, e.g. to the longitudinal axis of the bearing seat. The bearing seat is preferably positioned at a lever end of the lever adapter or in between the lever adapter. The axis symmetry of the restoring means to the lever adapter provides for a steady external force to the control adapter and therefore to a bearing, which indirectly connects the control adapter with a control shaft, which is statically mounted in the housing. The axes of the lever adapter and the restoring means may be orientated perpendicular to each other.

[0050] In a further preferable embodiment, the operating unit comprises a sliding sleeve, wherein the sliding sleeve is mounted between the bearing seat und the restoring means. The sliding sleeve is preferably mounted coaxially to the bearing seat and is statically (e.g. fixedly) mounted on the housing. The sliding sleeve may not contact the control adapter directly, while it separates the control adapter from the restoring means to reduce friction during a motion of the control adapter in use. Helical coils of the at least two torsion springs may be arranged on the outer surface of the sliding sleeve, i.e. the sliding sleeve may extend through the torsion springs. Contact between the coil portion of the helical springs and the control adapter may thus be prevented, which may reduce friction between the helical springs and the control adapter. Further, a spacing (in radial direction) may be provided between the helical spring and the sliding sleeve such that when the diameter of the torsion spring is reduced during tensioning of the spring, the spacing is of sufficient size to accommodate such reduction in diameter.

[0051] The sliding sleeve may comprise two sleeve portions, which may be equal, and which may be substantially cylindrical. Each sleeve portion may have a first axial end a second axial end and an outwardly directed receiving region between the first and the second axial ends for receiving at least one torsion spring on each of the sleeve portions.

[0052] Another embodiment of the invention further provides that the operating unit comprises at least two spring-loaded links, wherein the links are mounted on the housing, wherein each link each is divided by a step into a first guiding part and a second guiding part. The spring-loaded link generates an additional resistance against the movement of a pin in a pivoting direction. The pin may extend from the adapter stop parallel to the longitudinal axis, i.e. to the rotation axis of the control adapter. When the pin is moved against the step of the spring-loaded link during pivoting of the control adapter, the resistance may increase rapidly. Thus, a user needs to actively push the operating lever - hence the control adapter - there against. As the link is spring loaded, it may be moveable away from the pin so that the pin can pass over the step. After having passed the step, the pin transitions from movement along a first guiding part to a movement along the second guiding part of the link, which may be elevated relative to the first guiding part on the link. Said elevated (second) guiding part may be pushed down by the guiding pin against a force of a spring that is mounted underneath the link, especially underneath the second guiding part.

[0053] A first of the two spring loaded links may provide a respective step in a direction of the control adapter movement opposite to the direction in which a respective step of a second of the two spring loaded links is provided. By connecting the adapter stop with at least two spring-loaded links each comprising two guiding parts and a step, the haptic feedback experienced by the user may be improved and / or customized. For example, the step may be located midway between the first and second guiding part and may additionally overlap with the initial position of the control adapter. Thus, a user of the operation unit may need to overcome the restoring torque provided by the at least two torsion springs and the step when moving the lever out of the initial position. As a result, a haptic indication of the operating unit to the user that the initial position has been left may be improved. The safety of a machine that is operated by the operating unit may thus be improved.

[0054] According to a further embodiment of the invention, an operating element, in particular a joystick is provided. The operating element comprises an operating unit having any of the configurations described herein. The operating element may further comprise a user operable handle coupled, e.g. mounted, to the lever adapter. The handle may for example comprise a grip configured to be gripped by a user. The joystick may be a onedimensional joystick (pivoting of the handle in the first and second pivoting directions) or a two-dimensional joystick (additionally pivoting in directions perpendicular to the first and second directions). Such two-dimensional joystick may employ the further outer housing, as described above and further below.

[0055] According to a further embodiment of the invention, a machine, in particular a mobile machine, such as an agricultural or construction vehicle, is provided. The machine comprises an operating element configured to control a function of the machine. The operating element, e.g. joystick, may have any of the configurations described herein.

[0056] By such operating element or machine, advantages may be achieved that correspond to the advantages outlined further above with respect to the operating unit.

[0057] It is to be understood that the features mentioned above and those yet to be explained below can be used not only in the respective combinations indicated, but also in other combinations or in isolation, without leaving the scope of the present invention. In particular, the features of the different aspects and embodiments of the invention can be combined with each other unless noted to the contrary. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The invention is described in more detail below with reference to an embodiment with reference to the drawings. In the drawings, like reference numerals refer to like elements.

[0059] Fig- 1 shows a perspective view of an operating unit;

[0060] Fig- 2 shows a sectional side view of the operating unit of Fig. 1;

[0061] Fig. 3 shows a perspective view of the operating unit of Fig. 1 mounted in a further outer housing.

[0062] DETAILED DESCRIPTION

[0063] In the following, embodiments and / or examples of the invention will be described in detail with reference to the accompanying drawings. It is to be understood that the following description of the embodiments is given only for the purpose of illustration and is not to be taken in a limiting sense. It should be noted that the drawings are to be regarded as being schematic representations only. The representation of the various elements is chosen such that their function and general purpose become apparent to a person skilled in the art. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted.

[0064] Fig- 1 shows a perspective view of an operating unit 1 comprising a housing 2, wherein the housing 2 is separated into one first housing section 20 and two second housing sections 21. The first and second housing sections 20, 21 are attached to each other by screws. According to some preferable embodiments of the invention, the first and second housing sections 20, 21 can be attached to each other by clipping, pressing or wedging, too. A control adapter 3 is partly accommodated within the housing 2, wherein the control adapter 3 comprises a lever adapter 4 and a bearing seat 5 (shown in Fig. 2). The control adapter 3 is pivotally mounted along a longitudinal axis 6 of the bearing seat 5 in the housing 2, which thus provides a rotation axis for the pivoting.

[0065] The bearing seat 5 is connected to the housing 2 with a control shaft 22 through bearings (not shown). The control shaft 22 is positioned concentrically to the bearing seat 5. Restoring means 7 in form of two torsion springs 8 are positioned on both sides of the lever adapter 4. The two torsion springs 8 are positioned rotationally symmetrically by 180 degrees about the longitudinal axis of the lever adapter 4. A first end 9 of each torsion spring 8 rests on an adapter stop 11. The adapter stop 11 is positioned on an outer end 13 of the lever adapter 4. The adapter stop 11 extends parallel to the longitudinal axis 6 and has two grooves 23, which oppose each other along the longitudinal axis 6. The grooves 23 provide adapter surfaces 14, 14’, wherein each first end 9 of one torsion spring 8 rest on one of the adapter surfaces 14, 14’.

[0066] Optionally, the adapter stop 11 provides a pin 24 on each of its longitudinal ends, wherein each pin 24 rests on a spring-loaded link 16, wherein the link 16 is mounted on the housing 2. The link 16 is divided in a first guiding part 17 and a second guiding part 18 by a step 19. In an initial position of the control adapter 3, shown in Fig. 1, each pin 24 rests on the step 19 for a backlash-free position of the control adapter 3. If the control adapter 3 is deflected (e.g. pivoted about axis 6) in a first pivoting direction X, the link 16 is pushed downwards (when seen in Fig. 1, i.e. is pushed away from the pin), and the pin 24 changes its position from the first guiding part 17 to the second guiding part 18. One of the torsion springs 8 is taken along with the lever adapter 4 (by the respective adapter stop 11) and the other torsion spring 8 remains unchanged in its position (e.g., it may disengage from the groove 23 as the adapter stop 11 is moved away from the first end 9 of the spring). The second ends 10 of the torsion springs 8 rest on a housing stop 12, wherein each housing stop 12 is positively connected with the second end 10. For this, the housing stop 12 may be provided by two or four housing grooves in the first housing section 20, wherein each second end 10 is inserted in one of these housing grooves. Each second housing section 21 closes one or two of the housing grooves. If four housing grooves are provided, two may remain unused.

[0067] Fig- 2 shows a sectional side view of the operating unit 1, wherein the torsion spring 8 and the control shaft 22 are positioned coaxially to the bearing seat 5 of the control adapter 3. The first end 9 of the torsion spring 8 rests on a security stop 25 of the housing 2. The security stop 25 keeps the first end 9 in its initial position, while the control adapter 3, and hence the adapter stop 11, is deflected in a first pivoting direction X. The second end 10 of the torsion spring 8 rests on the housing stop 12. The angle between the first end 9 and the second end 10 in this initial position of the control adapter 3 may be 90°. Other angles may be used as well. The security stop 25 may keep the spring 8 in its initial state, e.g. in a pre-tensioned state, while the adapter stop 11 moves away from the first end 9 of the torsion spring 8 when pivoting in direction X. When pivoting in the opposite direction (X’), the adapter stop 11 takes along the first end 9 of torsion spring 8, whereupon the first end 9 may become disengaged from the security stop 25 (which may be fixed relative to the housing 2). The stops for the first end 9 of the second torsion spring may be configured in the same way but for the opposite pivoting direction (the arrangement may thus be mirrored when seen in the same direction as in Fig. 2), i.e. the first end of the second torsion spring may be taken along when pivoting in direction X).

[0068] This support of the torsion spring, in which the first end 9 is movable and the second end 10 is fixed, may also be reversed. For example, the first end 9 may be supported fixedly on the control adapter 3, and the housing stop may be provided fixed relative to the housing but such that the second end can disengage the housing stop when pivoting in the direction in which the spring is not tensioned. The security stop 25 may be provided fixed relative to the control adapter. When not applying a restoring torque while pivoting, both ends 9, 10 thus move with the control adapter, whereas in the opposite pivoting direction, the housing stop keeps the second end stationary so that the spring is tensioned during pivoting of the control adapter.

[0069] Optionally, a sliding sleeve 30 may be provided between each torsion spring 8 and the adapter bearing 5. Thus, when the torsion spring 8 is kept in its initial position while the control adapter 3 is pivoted, the sliding sleeve 8 may prevent contact between the torsion spring 8 and the bearing seat 5 and may thus reduce friction.

[0070] Fig. 3 shows a perspective view of the operating unit 1 mounted in a further outer housing 26, wherein the operating unit 1 is relatively pivotally mounted in the outer housing 26 along a pivoting axis 27, wherein the pivoting axis 27 is perpendicularly orientated to the longitudinal axis 6. Thus, a user is able to pivot the not shown operating lever and hence the control adapter 3 in the outer housing 26 along any of the pivoting directions X, X’, X”, X’” and sum of the overlapping of these pivoting directions X, X’, X”, X’”. The control adapter 3 can be pivoted about the longitudinal axis 6 by itself and / or indirectly about the pivoting axis 27, while the whole operating unit 1 is pivoted about the pivoting axis 27. Between the housing 2 and the outer housing 26, additional restoring means 7 are accommodated to restore the housing 2 and hence the operating unit 1 with the control adapter 3 in its initial position when the operating lever (not shown) is released by the user. The restoring occurs with respect to the outer housing 26. These additional restoring means 7 may be provided by two further torsion springs 8 each comprising a first end 9 and a second end 10, wherein the first ends 9 rest against the housing 2 and the second ends 10 rest against the outer housing 26. Each of the four torsion springs 8 are chosen in accordance with to the motion they restore, so each of the four torsion springs 8 can have a different spring ratio to optimize motion and haptic feedback to a user. It is also possible that all four torsions springs 8 are equal or at least two torsion springs 8 are equal.

[0071] The operating unit 1 of Fig. 3 may be used to implement a two dimensional joystick, wherein the operating lever may be a joystick handle including a grip for the hand of the user. According to a further embodiment, a machine including such joystick for controlling a function of the machine, such as propulsion in forward / rear direction, a steering direction, and / or a tool of the machine may be provided.

[0072] Particular aspects of the subject-matter disclosed herein are set out in the following numbered clauses. The embodiments disclosed in the following clauses may be pursued in the present application or in any divisional application.

[0073] 1. Operating unit comprising a housing for at least partially accommodating a control adapter comprising a lever adapter and a substantially cylindrical bearing seat, wherein the control adapter is pivotally mounted relative to the housing around a longitudinal axis of the bearing seat, and restoring means, wherein the restoring means are at least two torsion springs each comprising a first end and a second end, wherein the first ends rest against the control adapter and the second ends rest at least indirectly against the housing.

[0074] 2. Operating unit according to clause 1, wherein the first ends are pivotally mounted relative to the housing and the second ends are statically mounted relative to the housing.

[0075] 3. Operating unit according to clause 1 or 2, wherein the control adapter comprises at least one adapter stop to rest each first end of the restoring means there against and the housing comprises at least one housing stop to rest each second end of the restoring means there against.

[0076] 4. Operating unit according to clause 3, wherein the at least one adapter stop is positioned on an outer end of the lever adapter opposite the bearing seat and / or the at least one adapter stop is extended parallel to the longitudinal axis.

[0077] 5. Operating unit according to clause 3 or 4, wherein at least two first ends of the restoring means rest on different adapter surfaces of the adapter stop, wherein the different adapter surfaces oppose each other.

[0078] 6. Operating unit according to any of the preceding clauses, wherein the at least two torsion springs have a different spring ratio and / or a rectangular cross section. 7. Operating unit according to any of the preceding clauses, wherein the restoring means are orientated axisymmetric, perpendicular to the lever adapter.

[0079] 8. Operating unit according to any of the preceding clauses, wherein the operating unit comprises a sliding sleeve, wherein the sliding sleeve is mounted between the bearing seat und the restoring means.

[0080] 9. Operating unit according to any of clauses 3 to 8, wherein the operating unit comprises at least two spring-loaded links, wherein the links are mounted on the housing, wherein the links each are divided in a first guiding part and a second guiding part by a step.

[0081] While specific embodiments are disclosed herein, various changes and modifications can be made without departing from the scope of the invention. The present embodiments are to be considered in all respects as illustrative and non-restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

[0082] LIST OF REFERENCE NUMERALS

[0083] 1 operating unit

[0084] 2 housing

[0085] 3 control adapter

[0086] 4 lever adapter

[0087] 5 bearing seat

[0088] 6 longitudinal axis

[0089] 7 restoring means

[0090] 8 torsion spring

[0091] 9 first end

[0092] 10 second end

[0093] 11 adapter stop

[0094] 12 housing stop

[0095] 13 outer end

[0096] 14, 14' adapter surface

[0097] 16 link

[0098] 17 first guiding part

[0099] 18 second guiding part

[0100] 19 step

[0101] 20 first housing section 21 second housing section

[0102] 22 control shaft

[0103] 23 groove

[0104] 24 pin 25 security stop

[0105] 26 outer housing

[0106] 27 pivoting axis

[0107] 30 sliding sleeve

[0108] X, X‘, X“, X‘“ pivoting direction

Claims

Claims:

1. An operating unit comprising a housing (2) for at least partially accommodating a control adapter (3) comprising a lever adapter (4), wherein the control adapter(3) is pivotally mounted relative to the housing (2) around a rotational axis (6), the control adapter being pivotable from an initial position in a first pivoting direction and in a second pivoting direction that is opposite to the first pivoting direction, and restoring means (7) for restoring the control adapter (3) to the initial position, wherein the restoring means (7) comprises at least a first and a second torsion spring (8) each comprising a first end (9) and a second end (10), wherein the first torsion spring (8) is coupled at its first end (9) to the control adapter (3) and at its second end to the housing (2) at least during a tensioning of the first torsion spring (8), the coupling being configured such that when the control adapter (3) is pivoted from the initial position in the first pivoting direction, the first torsion spring (8) is tensioned to provide a restoring torque and when the control adapter (3) is pivoted from the initial position in the second pivoting direction, the first torsion spring (8) does not provide a restoring torque; and wherein the second torsion spring (8) is coupled at its first end (9) to the control adapter (3) and at its second end to the housing (2) at least during a tensioning of the second torsion spring (8), the coupling being configured such that when the control adapter (3) is pivoted from the initial position in the first pivoting direction, the second torsion spring (8) does not provide a restoring torque, and when the control adapter (3) is pivoted from the initial position in the second pivoting direction, the second torsion spring (8) is tensioned to provide a restoring torque.

2. The operating unit according to claim 1, wherein the at least first and second torsion springs (8) have an initial state in the initial position of the control adapter (3), wherein the coupling of the first and second torsion springs to the housing and the control adapter is such that when the control adapter (3) is pivoted from the initial position in the second pivoting direction, the first torsion spring (8) remains in its initial state, and when the control adapter (3) is pivoted from the initial position in the first pivoting direction, the second torsion spring (8) remains in its initial state.

3. The operating unit according to claim 1 or 2, wherein only the first end of the first torsion spring is taken along with the motion of the lever adapter in the first pivoting direction to tension the first torsion spring and wherein only the first end of the second torsion spring is taken along with the motion of the lever adapter in the second pivoting direction to tension the second torsion spring.

4. The operating unit according to any of the preceding claims, further comprising a stop (11, 12) for each of the first and second torsion springs (8), the stop being configured to provide a rest for the first end (9) or the second end (10) of the respective torsion spring (8), wherein the stop (11,12) is configured to stay in contact with the respective end (9, 10) of the torsion spring (8) when the respective torsion spring (8) is tensioned during pivoting of the control adapter (3), and is configured to allow the stop to move away from the respective end (9, 10) of the torsion spring (8) when the respective torsion spring (8) is not providing the restoring torque during pivoting of the control adapter (3).

5. The operating unit according to claim 4, wherein the respective other end of the respective torsion spring (8) is statically mounted relative to the housing (2) or to the control adapter (3), respectively.

6. The operating unit according to claim 4 or 5, wherein the stop is an adapter stop (11) provided on the control adapter (3), wherein the adapter stop (11) is configured to take along the end (9) of the respective torsion spring (8) when the control adapter (3) is pivoted in the pivoting direction to tension the respective torsion spring (8).

7. The operating unit according to claim 6, wherein the adapter stop (11) for the first torsion spring (8) and the adapter stop (11) for the second torsion spring (8) are provided as extensions that extend from the control adapter (3) in opposite directions, preferably in a direction parallel to the rotational axis (6).

8. The operating unit according to claim 6 or 7, wherein the adapter stop (11) for the first torsion spring (8) and the adapter stop (11) for the second torsion spring (8) each comprise a groove (23) configured to receive the first end (9) of the respective torsion spring (8), the groove (23) being configured to allow the first end (9) of the torsion spring (8) to engage and disengage the adapter stop (11).

9. The operating unit according to any of claims 6-8, wherein the first ends (9) of the first and second torsion springs (8) rest on different adapter surfaces (14,14’) of the adapter stops (11), wherein the different adapter surfaces (14, 14’) oppose each other.

10. The operating unit according to any of the preceding claims, wherein the first and second torsion springs (8) have an initial state that corresponds to the initial position of the control adapter (3), wherein the first and second torsion springs (8) are pretensioned in the initial state.

11. The operating unit according to any of the preceding claims, further comprising a security stop (25) for each torsion spring (8), wherein the security stop (25) is configured and arranged to retain the respective torsion spring (8) in an initial state by engaging an end (9, 10) of the respective torsion spring (8) during the pivoting of the control adapter (3) in the pivoting direction in which no restoring torque is applied by the respective torsion spring (8), and wherein the security stop (25) is further configured to allow the respective end (9, 10) of the respective torsion spring (8) to move away from the security stop (25) when the respective torsion spring (8) is tensioned during pivoting of the control adapter (3).

12. The operating unit according to claims 10 and 11, wherein in the initial position of the control adapter (3), an end (9, 10) of the respective torsion spring (8) rests against the security stop (25) to pretension the respective torsion spring (8).

13. The operating unit according to any of the preceding claims, wherein the control adapter (3) comprises a substantially cylindrical bearing seat (5), wherein the rotational axis is a longitudinal axis (6) of the bearing seat.

14. The operating unit according to any of the preceding claims, wherein the first ends (9) of the first and second torsion springs (8) rest against the control adapter (3) and the second ends (10) of the first and second torsion springs rest at least indirectly against the housing (2).

15. The operating unit according to any of the preceding claims, wherein the at least two torsion springs (8) have the same or a different spring ratio and / or have a rectangular cross section.

16. The operating unit according to any of the preceding claims, wherein the torsion springs are mounted concentrically with the rotational axis (6) of the control adapter, preferably concentrically with a bearing seat of the control adapter.

17. The operating unit according to any of the preceding claims when dependent on claim 13, wherein the operating unit comprises a sliding sleeve (30), wherein the sliding sleeve (30) is mounted between the bearing seat (5) and the restoring means (7).

18. The operating unit according to any of the preceding claims, wherein the operating unit (1) comprises at least two spring-loaded links (16), wherein the links (16) are mounted on or in the housing (2), wherein the links (16) each are divided into a first guiding part (17) and a second guiding part (18) by a step, and wherein a pin coupled to the control adapter (3) is guided on each of the at least two spring-loaded links (16).

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