Patent Description:
Tensable connecting elements, such as tensable screw connections, for tightening or connecting components are well known. Specifically, for installing such tensable connecting elements, the use of screw tensioning devices is known, for example, in the field of steel constructions and various engine design applications. These screw tensioning devices generally operate based on a torque-free tensioning method, according to which pulling forces are used to lengthen large screws or bolts in an elastic range during installation such that, upon releasing the pulling forces, the connecting elements retract and thereby apply tensional forces onto the components to be tightened.

For example, in a known use of the screw tensioning devices, at first, a first end of a screw is connected to a first component via a threaded means. Then, a second component to be fastened to the first component is provided such that a threaded rod of the screw extends therethrough. Via a second end of the screw, a nut is placed on the screw so as to be engaged to the threaded rod. Thereafter, the second end of the screw is engaged to the screw tensioning device and a pulling force is applied thereto so as to elastically lengthen the screw. In this lengthened state, the nut is further tightened such that, upon releasing the pulling force applied to the screw, the screw together with the nut apply a tensional force for frictional connecting the first to the second component.

Such a screw tensioning device, for example, is known from <CIT>. In the known device, pulling forces are used for tensioning a screw connecting element engaged to a fixation element of the device. Specifically, the known device comprises a support element configured to support the fixation element against a component to be tightened during tensioning operation. The fixation element is arranged to be movable relative to the support element so as to apply tension or to remove tension from the screw. Further, an actuating unit is provided for translationally actuating the fixation element relative to the support element. The actuating unit comprises an actuating element constituting an interface element for engagement with a tool for operating the device, i.e. by receiving an actuating torque. Specifically, the actuating unit is configured for transforming or translating a rotational movement applied to the actuating element into a translational movement of the fixation element relative to the support element.

<CIT> refers to a gear unit comprised of a central active gear used as an input element and a plurality of slave gears arranged around and engaging with the active gear. Attached to the slave gears are shafts configured to form-fittingly engage with nuts to be tightened. Upon rotational actuation of the active gear, the plurality of slave gears start to rotate accordingly and tighten a plurality of nuts simultaneously.

<CIT> refers to an apparatus for simultaneously applying torque to a plurality of jackbolts of a multi-jackbolt tensioner. The apparatus comprises a planetary gear assembly for transforming an input torque into an output torque being applied to a plurality of coupling sockets, each of which is connected to one jackbolt.

<CIT> discloses a fastening tool for a fuel cell having socket members individually engaging with fastening members for simultaneously fastening a large number of unit cells layered on each other.

Further, hydraulically driven screw tensioning devices are known, in which the fixation element is hydraulically actuated to be moved relative to the support element.

In engine design applications, usually, more than one tensable connecting element is used for structurally connecting elements of an engine. For example, for assembly of a cylinder head, four tensable screws are used. In the known applications, screw tensioning devices may be used to successively mount the tensable screws which may be time-consuming and have effects on cycle times during assembly.

In view of the prior art, it is an objective to provide an apparatus and a method which enables a time-efficient assembly in applications, where more than one tensable connecting element is used.

This object is solved by means of an apparatus for simultaneously actuating at least two screw tensioning devices having the technical features of claim <NUM>, the use of such an apparatus having the technical features of claim <NUM> and a method for simultaneously actuating at least two screw tensioning devices having the technical features of claim <NUM>. Preferred embodiments are set forth in the present specification, the Figures as well as the dependent claims.

Accordingly, an apparatus for simultaneously actuating at least two screw tensioning devices is provided, comprising a transmission input element for engagement with a tool; at least two transmission output elements, each of which is connectable to one of the screw tensioning devices and rotatably mounted around a rotational axis; and a gear unit configured to transfer a rotational movement of the transmission input element into a rotational movement of each one of the transmission output elements around their rotational axis, wherein the gear unit comprises a central gear fixed to the transmission input element and connected or connectable to each one of the transmission output elements in a torque-transmitting manner, wherein the central gear is movable between an engagement position, in which a torque-transmitting connection to the transmission output elements is engaged, and a disengagement position, in which the torque-transmitting connection to the transmission output elements is released
and/or wherein
the gear unit comprises at least two intermediate gears connected or connectable to the transmission input element and one associated transmission output element in a torque-transmitting manner, wherein each one of the intermediate gears is movable between an engagement position, in which a torque-transmitting connection between the transmission input element and the associated transmission output element is engaged, and an disengagement position, in which the torque-transmitting connection between the transmission input element and the associated transmission output element is released.

Furthermore, a use of the above described apparatus is provided for simultaneously actuating at least two screw tensioning devices.

To that end, a method for actuating at least two screw tensioning devices is provided, comprising the steps of providing the above described apparatus, connecting each one of the at least two transmission output elements of the apparatus to one actuating element of the screw tensioning devices, and rotationally actuating the transmission input element of the apparatus to simultaneously actuate the screw tensioning devices.

In the following, the invention will be explained in more detail with reference to the accompanying Figures. In the Figures, like elements are denoted by identical reference numerals and repeated description thereof may be omitted in order to avoid redundancies.

<FIG> schematically shows an apparatus <NUM> for simultaneously actuating four screw tensioning devices <NUM> connected to the apparatus <NUM>, respectively. The apparatus <NUM> comprises a housing <NUM> which, for overview reasons, is transparently depicted.

The shown apparatus <NUM> may be used to operate the screw tensioning devices <NUM> so as to tension, i.e. preload, and/or loosen, i.e. untighten, four tensable screw connections simultaneously. In the context of the present disclosure, the term "tensable" refers to a material property indicating that a component, screw connection, at least partially, is capable of being elastically expanded and thus of storing an amount of elastic energy when being subjected to a tensioning force.

For doing so, the shown apparatus <NUM> comprises a transmission input element <NUM> for engagement with a tool so as to receive an input torque T1 for actuating the apparatus <NUM>, four transmission output elements <NUM>, each of which is releasably connected to one screw tensioning device <NUM> and is rotatably mounted in the housing <NUM> around a rotational axis <NUM>, and a gear unit <NUM> for coupling the transmission input element <NUM> and the transmission output elements14. Specifically, the gear unit <NUM> is configured to transfer a rotational movement R1 of the transmission input element <NUM> into a rotational movement of each one of the transmission output elements <NUM> around their rotational axis <NUM>, as indicated in <FIG> by arrows R1 and R2. Although the arrows indicating the rotational movement of the transmission input element <NUM> and the transmission output elements <NUM> point in only one direction, the apparatus <NUM> is configured such that the transmission input element <NUM> and thus the transmission output elements <NUM> can rotate reversely.

Specifically, as depicted in <FIG>, each of the transmission output elements <NUM> is form-fittingly coupled to an actuating element <NUM> of one screw tensioning device <NUM> so as to transfer an output torque T2 thereto. In this way, upon rotation of the transmission input element <NUM>, the transmission output elements <NUM> are rotated around their rotational axis <NUM> together with the associated actuating element <NUM> of the screw tensioning device <NUM>. As a result, by rotating the actuating element <NUM>, the screw tensioning device <NUM> is operated so as to perform tensioning or loosening of a tensable connecting element <NUM>.

In the following, the screw tensioning device <NUM>, i.e. in view of its structure and operation, is further specified under reference to <FIG>.

The screw tensioning device <NUM> is intended for tensioning, i.e. preloading, and/or loosening, i.e. untightening, one tensable connecting element <NUM>. Specifically, the connecting element <NUM> is provided in the form of a screw comprising a first end <NUM>, an opposed second end <NUM> and an elastic part positioned between the first end <NUM> and the second end <NUM>. The elastic part is capable of being elastically lengthened when the connecting element <NUM> is subjected to a pulling force by means of the device <NUM>.

The connecting element <NUM> is configured for connecting, i.e. force- and/or form-fittingly connecting, a first component <NUM> to a second component <NUM>. Specifically, the first end <NUM> of the connecting element <NUM> is configured to be connected to the first component <NUM> by means of a threaded engagement, as depicted in <FIG>. The elastic part of the connecting element <NUM> extends through the second component <NUM> such that the second end <NUM> of the connecting element <NUM> is positioned on a side of the second component <NUM> facing away from the first component <NUM>. For connecting the first and the second component <NUM>, <NUM>, a nut <NUM> is provided which is in threaded engagement with the elastic part of the connecting element <NUM>.

The device <NUM> comprises an engagement element <NUM> connectable to the connecting element <NUM>. Specifically, the engagement element <NUM> includes a cylindrical portion <NUM> having a first end <NUM> and a second end <NUM>. At the first end <NUM>, the engagement element <NUM> includes a cylindrical recess <NUM> to house the second end <NUM> of the connecting element <NUM>, while the first end <NUM> of the connecting element <NUM> is connected to the first component <NUM> by means of the threaded engagement. The recess <NUM> includes internal threads <NUM> formed on a side wall <NUM> of the engagement element <NUM> to engage with complementary threads <NUM> formed at the second end <NUM> of the connecting element <NUM>.

Further, the device <NUM> comprises a support element <NUM> configured to support the engagement element <NUM> against the second component <NUM>. The engagement element <NUM> is translationally movable relative to the support element <NUM>, i.e. along a longitudinal axis <NUM> of the device. Specifically, upon translationally moving the engagement element <NUM> relative to the support element <NUM>, a tensioning force may be applied to or may be removed from the connecting element <NUM> fixed to the engagement element <NUM>.

The device <NUM> further comprises an actuating unit <NUM> for translating the rotational movement applied to the actuating element <NUM> into a translational movement of the engagement element <NUM> relative to the first and second component <NUM>,<NUM> to be tightened and thus relative to the support element <NUM>. In other words, the actuating unit <NUM> is provided so as to actuate the engagement element <NUM> relative to the support element <NUM>. In the following, the structure and operation of the actuating unit <NUM> is explained in more detail.

The actuating unit <NUM> is at least partly hydraulically actuated. In other words, a hydraulic fluid is used to transfer motive power so as to move the engagement element <NUM> relative to the support element <NUM>. For doing so, the actuating unit <NUM> comprises a piston <NUM> accommodated within and movable relative to the engagement element <NUM>, i.e. along the longitudinal axis <NUM>. Further, a fluid chamber <NUM> accommodating the fluid is provided which is delimited by the piston <NUM>, the engagement element <NUM> and the support element <NUM>. In this configuration, the actuating unit <NUM> is designed such that a translational movement of the piston <NUM> manipulates a volume of the fluid chamber <NUM> and thereby moves the engagement element <NUM> with respect to the support element <NUM> so as to apply or remove a tension acting on the connecting element <NUM> connected to the engagement element <NUM>.

More specifically, the fluid chamber <NUM> comprises two distinct portions, a piston portion <NUM> delimited by and provided between the piston <NUM> and the engagement element <NUM> and an effective portion <NUM> delimited by and provided between the engagement element <NUM> and the support element <NUM>. The piston portion <NUM> and the effective portion <NUM> are fluid-communicatively connected via two connecting bores <NUM> provided in the engagement element <NUM>. A base area <NUM> of the piston portion <NUM> is provided with an effective cross section that is smaller than an effective cross section of a base area <NUM> of the effective portion <NUM>. In this context, the "effective cross section" refers to an area that is perpendicular to the longitudinal direction <NUM> and thus perpendicular to a moving direction of both the piston <NUM> and the engagement element <NUM> relative to the support element <NUM>. By this configuration, an actuating force applied onto the piston <NUM> is hydraulically transformed into a force acting on the engagement element <NUM> that is higher compared to the actuating force acting on the piston <NUM>.

For accommodating the piston <NUM>, the engagement element <NUM> further includes a bore <NUM> extending along the longitudinal axis <NUM> of the device <NUM>. Specifically, the bore <NUM> extends from the second end <NUM> of the cylindrical portion <NUM> to the recess <NUM> formed at the first end <NUM> of the cylindrical portion <NUM> of the engagement element <NUM> and is configured to receive the piston <NUM>. A diameter of the bore <NUM> may be less than the diameter of the recess <NUM> which thus together form a stepped opening within the engagement element <NUM>. Further, the bore <NUM> includes a variable diameter along the longitudinal axis <NUM>. In other words, a wall of the engagement element <NUM> has a variable width along the length of the bore <NUM> such that the diameter of the bore <NUM> changes along the length of the bore <NUM>. As depicted in <FIG>, the bore <NUM> includes a wider portion <NUM> and a narrower portion <NUM>. At the wider portion <NUM>, a distance between the piston <NUM> and the wall of the engagement element <NUM> is greater than at the narrower portion <NUM>.

As shown in <FIG>, at the narrower portion <NUM>, the piston <NUM> contacts the wall of the engagement element <NUM>. The narrower portion <NUM> includes a groove <NUM> formed in the wall of the engagement element <NUM> and extending along a perimeter of the bore <NUM>. A first sealing ring <NUM> is disposed in the groove <NUM> to form a seal joint between the piston <NUM> and the engagement element <NUM>. The first sealing ring <NUM> is positioned between the piston <NUM> and the wall of the engagement element <NUM>.

The engagement element <NUM> also includes a plate <NUM> extending radially from the cylindrical portion <NUM> of the engagement element <NUM>. The plate <NUM> is positioned normal to the longitudinal axis <NUM> and is proximal to the second end <NUM> of the engagement element <NUM>. The plate <NUM> is cylindrical in shape and forms a flange portion in proximity to the second end <NUM> of the engagement element <NUM>.

The engagement element <NUM> is received at least partly within the support element <NUM>. As set forth above, the engagement element <NUM> is arranged and adapted to be moved relative to the support element <NUM> to apply tension to or remove tension from the connecting element <NUM>. The support element <NUM> includes a first cylindrical portion <NUM> and a second cylindrical portion <NUM> connected to one another by a connection portion <NUM>. The first cylindrical portion <NUM> forms a lower part of the support element <NUM> to be positioned on the second component <NUM>. The first cylindrical portion <NUM> surrounds a part of the connecting element <NUM>, the first end <NUM> of the engagement element <NUM> and a portion of the cylindrical portion <NUM> of the engagement element <NUM>. Specifically, the first cylindrical portion <NUM> surrounds the portion of the cylindrical portion <NUM> which is positioned underneath the plate <NUM> in the illustration depicted in <FIG>.

The second cylindrical portion <NUM> is spaced away from the first cylindrical portion <NUM> by the connection portion <NUM>. The second cylindrical portion <NUM> surrounds the plate <NUM> of the engagement element <NUM> such that an inner surface of the second cylindrical portion <NUM> contacts an outer surface of the plate <NUM>. In other words, the plate <NUM> is positioned within the second cylindrical portion <NUM> of the support element <NUM> and is configured to move relative to the second cylindrical portion <NUM>.

Further, a third sealing ring <NUM> is positioned between the inner surface of the second cylindrical portion <NUM> and the outer surface of the plate <NUM> to prevent leakage of the fluid accommodated in the fluid chamber <NUM>. Specifically, the third sealing ring <NUM> may be positioned in a groove formed either into the inner surface of the second cylindrical portion <NUM> or into the outer surface of the plate <NUM>, as depicted in <FIG>.

As can be gathered from <FIG>, the first cylindrical portion <NUM>, the second cylindrical portion <NUM>, and the connection portion <NUM> are hollow cylindrical portions having inner diameters different from each other, thereby forming stepped configurations with each other. The inner diameter of the connection portion <NUM> is smaller than the inner diameters of both the first cylindrical portion <NUM> and the second cylindrical portion <NUM>. The connection portion <NUM> comprises an opening to guide the engagement element <NUM> within the support element <NUM>, which opening has a diameter slightly larger than the diameter of the portion of the engagement element <NUM> guided by the support element <NUM>. The connection portion <NUM> may further define a recess in which a second sealing ring <NUM> may be disposed for providing a sealing between the engagement element <NUM> and the connection portion <NUM>.

The plate <NUM>, the connection portion <NUM>, and the second cylindrical portion <NUM> of the support element <NUM> together form the effective portion <NUM> of the fluid chamber <NUM>. The effective portion <NUM> is fluidly connected to the bore <NUM> in the engagement element <NUM> via the connecting bores <NUM>. The effective portion <NUM> is configured to receive the fluid from the piston portion <NUM> accommodated in the bore <NUM> of the engagement element <NUM> due to an axial movement of the piston <NUM> slidably positioned within the engagement element <NUM>.

In this way, the fluid may move back and forth between the piston portion <NUM> and the effective portion <NUM> of the fluid chamber <NUM>. During operation, the position of the piston <NUM> determines how much fluid is displaced from the piston portion <NUM> to the effective portion <NUM>, and vice versa. As can be gathered from <FIG>, when the piston <NUM> is moved in an upward direction, i.e. in a direction facing away from the engagement element <NUM>, the size of the piston portion <NUM> gets smaller. Accordingly, fluid is displaced therefrom into the effective portion <NUM> causing an increase of pressure in the effective portion <NUM> as more and more fluid enters thereinto. This pressure acts on the engagement element <NUM> which causes it to move in a direction facing away from the support element <NUM>, i.e. along the longitudinal axis <NUM>. This movement induces tensioning and thus lengthening of the connecting element <NUM>. In this tensioned and lengthened state of the connecting element <NUM>, an operator may tighten the nut <NUM> so as to position the nut <NUM> closer to the second component <NUM>, i.e. to abut on the second component <NUM>. This may be performed by reaching the nut <NUM> through openings in the support element <NUM> with a tool, an end of which may be inserted into the openings at the side of the nut <NUM> to turn and thus tighten or loosen the nut <NUM>.

The piston <NUM> has a generally cylindrical shape with a head end <NUM> and a rod end <NUM> that are distal to one another and connected by a shaft <NUM>. The head end <NUM> has a sealing portion <NUM> that is larger in diameter than the shaft <NUM>. The diameter of sealing portion <NUM> corresponds to a diameter of the bore <NUM> in the engagement element <NUM>. The sealing portion <NUM> comprises a recess <NUM> that is circular in nature. A fourth sealing ring <NUM> is provided within the recess <NUM>.

The first to fourth sealing ring <NUM>, <NUM>, <NUM>, <NUM> may be made from metal, such as iron or steel, ceramics, fibrous materials, elastomer and/or plastic.

The piston <NUM> further includes a threaded portion <NUM> that is in threaded engagement with a cap <NUM> of the engagement element <NUM>. The cap <NUM> is firmly fixed to the second end <NUM> of the cylindrical portion <NUM> by means of a threaded connection <NUM>. Alternatively, the cap <NUM> may be pressed to the second end <NUM> of the cylindrical portion <NUM> of the engagement element <NUM>.

In the shown configuration, the actuating element <NUM> is formed by the rod end <NUM> of the piston <NUM>. As the piston <NUM> and thus the actuating element <NUM> are connected to the cap <NUM> by means of a threaded engagement, the actuating unit <NUM> is designed such that a rotational movement of the actuating element <NUM> is transformed into a translational movement of the piston <NUM> relative to the engagement element <NUM> which manipulates the volume of the fluid chamber <NUM> and thereby moves the engagement element <NUM> with respect to the support element <NUM>. As a result, upon rationally manipulating the actuation element <NUM>, a tensioning or loosening of the connecting element <NUM> connected to the engagement element <NUM> is performed.

In the following, under reference to <FIG> and <FIG>, the structure and operation of the apparatus <NUM> is further specified.

The apparatus <NUM> is provided with the transmission input element <NUM> for receiving the input torque T1 applied thereto by means of a tool, i.e. a manual or electrical screwdriver. Accordingly, the transmission input element <NUM> is configured for being releasably connected to the tool. For doing so, the transmission input element <NUM> comprises an interface element <NUM> provided at an end portion thereof which protrudes from the housing <NUM> for ensuring a good accessibility. The interface element <NUM> is a recessed connecting element in the form of a socket head which is form-fittingly connectable to an actuated hex key rod of the tool.

The transmission input element <NUM> is rotatably mounted in the housing <NUM> around a further rotational axis <NUM> by means of a bearing (not shown). The further rotational axis <NUM> is parallel to and spaced apart from the rotational axis <NUM> of the transmission output element <NUM>. Further, opposed to the interface element end, the transmission input element <NUM> is fixed to a central gear <NUM> by means of a form-fitting and torque-transmitting coupling <NUM>, i.e. by means of a key, such that the central gear <NUM> is rotated upon rotation of the transmission input element <NUM>. The coupling is provided such that the central gear <NUM> is movable relative to the transmission input element <NUM> along the further rotational axis <NUM>, as indicated by an arrow in <FIG>, between an engagement position as shown in <FIG> and a disengagement position as shown in <FIG>.

In the engagement position, the central gear <NUM> is configured to enable or engage a torque-transmitting connection to each one of the transmission output elements <NUM> such that, upon rotation of the transmission input element <NUM>, each one of the transmission output elements <NUM> is rotated about their rotational axis <NUM>. In other words, in this position, the central gear <NUM> is connectable to each one of the transmission output elements in a torque-transmitting manner. However, when the central gear <NUM> is positioned in its disengagement position, the torque-transmitting connection between the transmission input element <NUM> and each one of the transmission output elements <NUM> is released such that, upon rotation of the transmission input element <NUM>, none of the transmission output elements <NUM> is rotated about their rotational axis <NUM>. The apparatus <NUM> is configured such that an operator may move the central gear <NUM> between its engagement position and disengagement position. In one configuration, the central gear <NUM> may be preloaded towards its engagement position by means of a spring element.

The central gear <NUM> forms a part of the gear unit <NUM>. Thus, by being provided with the movable central gear <NUM>, the shown apparatus <NUM> is configured for being operated in an engaged operating state, in which the gear unit <NUM> is configured to transfer a rotational movement of the transmission input element <NUM> into a rotational movement of each one of the transmission output elements <NUM> around their rotational axis <NUM>, and a disengaged operating state, in which, upon rotation of the transmission input element <NUM>, none of the transmission output elements <NUM> rotates around its rotational axis <NUM>. Specifically, for operating the apparatus <NUM> in its engaged operating state, the central gear <NUM> may be moved into its engagement position as depicted in <FIG>. Accordingly, for operating the apparatus <NUM> in its disengaged operating state, the central gear <NUM> may be moved into its disengagement position as depicted in <FIG>.

As set forth above, each one of the transmission output elements <NUM> is rotatably mounted in the housing <NUM> around their rotational axis <NUM>. In the shown apparatus <NUM>, the rotational axes <NUM> of the transmission output elements <NUM> are parallel to one another and spaced apart from one another such that they do not coincide.

Each one of the transmission output elements <NUM> is connected to one actuating element <NUM> of a screw tensioning device <NUM>. By such a configuration, the screw tensioning devices <NUM> are actuated upon rotational movement of the associated transmission output element <NUM>. For being connectable to the actuating element <NUM> of the screw tensioning device <NUM>, each one of the transmission output elements <NUM> comprises a further interface element <NUM> which protrudes from the housing <NUM> for ensuring a good accessibility. The further interface element <NUM> is a connecting element in the form of a hex key rod which is form-fittingly connectable to a socket head provided at the recessed rod end <NUM> of the actuating element <NUM>. In this way, a releasable torque-transmitting connection is provided between the transmission output elements <NUM> and the respective screw tensioning devices <NUM>. In this configuration, the rotational axis <NUM> of the transmission output element <NUM> coincides with a longitudinal axis of the actuating element <NUM> and thus with the longitudinal axis <NUM> of the screw tensioning device <NUM>.

Further, each one of the transmission output elements <NUM> comprises a shaft <NUM> rotatably mounted in the housing <NUM> by means of a bearing (not shown), at an end portion of which the further interface element <NUM> is provided. At each shaft <NUM>, an outer gear <NUM> is firmly fixed which is connectable to the central gear <NUM> in a torque-transmitting manner via an intermediate gear <NUM>.

Each one of the intermediate gear <NUM> is coupled to a further shaft <NUM> rotatably mounted in the housing <NUM> around a third rotational axis <NUM> being parallel to and spaced apart from the rotational axis <NUM> of the transmission output elements <NUM> and the further rotational axis <NUM> of the transmission input element <NUM>. Specifically, the intermediate gear <NUM> is coupled to the further shaft <NUM> by means of a form-fitting and torque-transmitting coupling <NUM>, i.e. by means of a key, such that the intermediate gear <NUM> is movable relative to the further shaft <NUM> along the third rotational axis <NUM>, as indicated by an arrow in <FIG>, between an engagement position as shown in <FIG> and a disengagement position as shown in <FIG>.

In the engagement position, the intermediate gear <NUM> is configured to enable or engage a torque-transmitting connection between the transmission input element <NUM> and the associated transmission output element <NUM> such that, upon rotation of the transmission input element <NUM>, the associated transmission output elements <NUM> is rotated about its rotational axis <NUM>. In other words, the respective intermediate gear <NUM> is connectable to the transmission input element <NUM> and the associated transmission output element <NUM> in a torque-transmitting manner.

By contrast, when the intermediate gear <NUM> is positioned in its disengagement position, the torque-transmitting connection between the transmission input element <NUM> and the associated transmission output element <NUM> is released such that, upon rotation of the transmission input element <NUM>, the associated transmission output element <NUM> is not rotated about its rotational axis <NUM>. The apparatus <NUM> is configured such that an operator may selectively move each one of the intermediate gears <NUM> between its engagement position and disengagement position. In one configuration, the intermediate gears <NUM> may be preloaded towards their engagement position by means of a spring element.

The intermediate gears <NUM> form a part of the gear unit <NUM>. Thus, by being provided with the movable intermediate gears <NUM>, the gear unit <NUM> is configured to selectively transfer a rotational movement of the transmission input element <NUM> into a rotational movement of at least one of the transmission output elements <NUM>. This means that the gear unit <NUM> may set individually for each transmission output element <NUM>, i.e. independently from the other transmission output elements <NUM>, whether or not the rotational movement of the transmission input element <NUM> is transferred into a rotational movement of the respective transmission output element <NUM>. In other words, the gear unit <NUM> is configured to selectively engage or release the torque-transmitting connection, i.e. for rotationally actuating the transmission output elements <NUM> around their rotational axis <NUM>, between the transmission input element <NUM> and the individual transmission output elements <NUM>.

In other words, by being provided with the intermediate gears <NUM>, the apparatus <NUM> is configured for being operated in a partially engaged operating state, in which the gear unit <NUM> is configured to, for at least one transmission output element <NUM>, engage a torque-transmitting connection to the transmission input element <NUM> for rotational actuation of the at least one transmission output element <NUM> and, for at least one other transmission output element <NUM>, release the torque-transmitting connection to the transmission input element <NUM>. In this state, only a part of the transmission output elements <NUM>, i.e. one, two or three transmission output elements <NUM>, is rotated about their rotational axis <NUM> upon rotation of the transmission input element <NUM>, while the at least one other transmission output element <NUM> is not actuated.

In the shown configuration, the gear unit <NUM> is configured such that, upon rotational actuation of the transmission input element <NUM>, an absolute value of a rotational speed of the transmission input element <NUM> is higher compared to an absolute value of a rotational speed of the transmission output element <NUM>.

<FIG> shows a further embodiment of the apparatus <NUM>. Compared to the configuration depicted in <FIG>, the apparatus <NUM> comprises four torque multiplier units <NUM> interposed between the transmission output elements <NUM> and the actuating elements <NUM> of the screw tensioning devices <NUM>, respectively. Specifically, each of the torque multiplier units <NUM> is connected to one transmission output element <NUM> and to one actuating element <NUM> of a screw tensioning device <NUM>, wherein each torque multiplier unit <NUM> is configured to transform the output torque T2 applied to the associated transmission output element <NUM> into an actuating torque T3 acting on the associated actuating element <NUM> which absolute value is higher compared to the output torque T2. For doing so, the torque multiplier units <NUM> may be equipped with a planetary gear. The planetary gear may comprise a sun gear connected to the transmission output element <NUM>, at least one planet gear supported by a carrier connected to a torque output element <NUM> of the torque multiplier unit and a ring gear fixed to a housing <NUM> of the apparatus <NUM> in a torque-transmitting manner. In this configuration, the torque output element <NUM> is provided with a third interface element designed similar to the further interface element <NUM> of the transmission output element so as to establish a form-fitting connection to the actuating element <NUM>.

It will be obvious for a person skilled in the art that these embodiments and items only depict examples of a plurality of possibilities. Hence, the embodiments shown here should not be understood to form a limitation of these features and configurations. Any possible combination and configuration of the described features can be chosen according to the scope of the invention as defined in the claims.

This is in particular the case with respect to the following optional features which may be combined with some or all embodiments, items and/or features mentioned before in any technically feasible combination.

An apparatus may be provided for simultaneously actuating at least two screw tensioning devices. The apparatus may comprise a transmission input element for engagement with a tool; at least two transmission output elements, each of which is connectable to a screw tensioning device and is rotatably mounted around a rotational axis; and a gear unit configured to transfer a rotational movement of the transmission input element into a rotational movement of each one of the transmission output elements around their respective rotational axis.

In the provided apparatus, the transmission output elements are connectable to one screw tensioning device, respectively, and are simultaneously rotated upon rotation of the transmission input element. In this way, the provided apparatus enables to simultaneously actuate at least two screw tensioning devices via the transmission output elements. The apparatus therefore enables time-efficient assembly in applications, where at least two tensable screw connections are utilized.

Specifically, by means of the gear unit, the provided apparatus is configured to mechanically actuate more than one screw tensioning device. Compared to configurations, in which a plurality of hydraulically driven screw tensioning devices are simultaneously actuated by means of a common pressure source, the suggested apparatus may have a less complex design and may enable a safer and less effortful assembly procedure for an operator. As to substance, for hydraulically actuating more than one screw tensioning device by means of a common pressure source, a certain volume of hydraulic fluid is required. In such configurations, for actuating the screw tensioning devices, the hydraulic fluid has to be exerted to high-pressure which, however, causes compression of the same. In this way, the hydraulic fluid stores mechanical energy which may pose a hazard potential. In contrast thereto, by mechanically actuating screw tensioning devices as enabled by the suggested apparatus, both hazard potential induced by pressurized fluid as well as guiding and storing of pressurized fluid may be omitted, thereby enabling a safer and less complex apparatus for actuating more than one screw tensioning device.

Generally, the proposed apparatus may be used, for example, in the field of steel constructions and various engine design applications, but is not limited thereto. Rather, the proposed device may be used in any application in which more than one tensable screw is tightened by employing torque-free tensioning methods. In one example, the proposed apparatus may be used to fasten a turbo charger to an engine crank case by means of more than one tensable screw.

Specifically, the apparatus may be used for actuating at least two screw tensioning devices or any other devices for tensioning and/or loosening a tensable connecting element. The tensable connecting elements may be or comprise a tensable screw, a tensable bolt and/or any other type of tensable connecting element.

Further, the connecting element to be tensioned and/or loosened by such tensioning devices may be intended and/or configured to tighten a component to which it is fastened. Alternatively or additionally, the connecting element to be tensioned and/or loosened by may be intended and/or configured for connecting, i.e. form- and/or force-fittingly connecting, a first component to a second component. For doing so, a first end of the connecting element may be fixed to the first component, i.e. by means of a threaded engagement. For example, the first component may be an engine crank case and the second element may be a turbo charger mount.

In the following, an exemplary configuration of a screw tensioning device to be actuated by the proposed apparatus is specified. The proposed apparatus may be used for actuating at least one such screw tensioning device, but is not limited thereto. Rather, the proposed apparatus may be configured to actuate other types of screw tensioning devices, i.e. screw tensioning devices which are operable by rotationally actuating an actuating element.

The screw tensioning device may comprise an engagement element connectable to the connecting element. In other words, the engagement element may be configured for being connected to the connecting element, i.e. in a force- and/or form-fitting manner. For doing so, the engagement element may comprise an engagement section for engaging with the connecting element. Specifically, the engagement section may be engaged with the connecting element by means of a threaded engagement. The engagement section may be provided at an end portion of the engagement element. Further, the engagement section may be configured to engage with a second end of the connecting element arranged opposed to the first end thereof. For example, the engagement section may be provided with a thread designed complementary to a thread formed at the second end of the connecting element.

The screw tensioning device may further comprise a support element configured to support the engagement element against the component to be tightened during tensioning operation of the device. In other words, the support element is configured to, during the tensioning operation of the screw tensioning device, abut on the component to be tightened, i.e. on the first or the second component. In this way, the support element is capable of generating a force, i.e. a reaction force, counteracting the pulling force exerted onto the connecting element connected to the engagement element during tension operation of the device. The screw tensioning device is provided such that the engagement element is translationally movable relative to the support element, i.e. along a longitudinal axis of the device. Upon translationally moving the engagement element relative to the support element, a tensioning force may be applied to or may be removed from the connecting element fixed to the engagement section. Thus, the device may be provided such that the engagement element is translationally movable relative to the support element so as to apply a tension to or to remove a tension from the connecting element.

The screw tensioning device may further comprise an actuating unit for the engagement element, i.e. for translationally moving the engagement element relative to the support element and thus relative to the component to be tightened. The actuating unit may comprise the actuating element and may be configured for translating a rotational movement applied to the actuating element into a translational movement of the engagement element relative to the component to be tightened and thus relative to the support element. An exemplary configuration of such an actuating unit, i.e. of interlinking the actuating element to the engagement element, is specified in connection with <FIG> and its accompanying description.

In the following the configuration of the apparatus is further specified which may be configured for simultaneously actuating at least two above describe screw tensioning devices.

The apparatus may comprise the transmission input element for engagement with a tool. In other words, the transmission input element may be configured for being releasably connected to a tool. The tool may be a manually actuated or electrically actuated tool, i.e. a manual or electrical screwdriver or an electric actuator. Specifically, the transmission input element may be provided with an interface element for receiving an actuating or input torque. For doing so, the interface element may be designed and configured for being releasably connected to the tool in a torque-transmitting manner. The transmission input element may be provided with a connecting element complementary designed to a further connecting element provided at the tool so as to provide a releasable form-fitting connection. For example, the connecting element may have a polygonal profile, i.e. a hexagonal profile. Accordingly, the transmission input element may constitute a socket head which is form-fittingly connectable to, for example, a hex key rod of the tool, or vice versa.

Further, the transmission input element may be rotatably mounted in the apparatus around a further rotational axis. The further rotational axis of the transmission input element may coincide with or be parallel to a longitudinal axis of the apparatus and/or the transmission input element. Further, the further rotational axis of the transmission input element may be parallel to the longitudinal axis of at least one screw tensioning device. For example, the further rotational axis of the transmission input element may be parallel to the longitudinal axis of each one of the screw tensioning devices.

As set forth above, the apparatus may comprise the at least two transmission output elements. For example, the apparatus may comprise four or more transmission output elements. Each of the at least two transmission output elements is connectable to one of the at least two screw tensioning devices, respectively. In other words, each of the at least two transmission output elements may be associated to merely one screw tensioning device. Thus, in a state, in which the apparatus is engaged with the at least two screw tensioning devices, each of the transmission output elements is connected to a different one of the at least two screw tensioning devices. In this state, the screw tensioning devices are actuated upon rotational movement of the transmission output elements.

Specifically, the transmission output elements may be configured for being releasably connected to an actuating unit of the screw tensioning device in a torque-transmitting manner. The actuating element of the screw tensioning devices may be configured to receive an actuating torque so as to operate the screw tensioning device. In other words, by rotationally actuating the actuating element, the screw tensioning device is operated so as to perform a screw tensioning operation.

For being connectable to the actuating element of the associated screw tensioning device, each of the transmission output elements may comprise a connecting element designed complementary to a further connecting element of the actuating element so as to provide a releasable form-fitting connection. For example, the connecting element of the transmission output element may have a polygonal profile, i.e. a hexagonal profile. Accordingly, the transmission output element may constitute a socket head which is form-fittingly connectable to, for example, a hex key rod of the actuating element, or vice versa.

In the apparatus, each of the transmission output elements may be rotatably mounted around a respective rotational axis. The rotational axes of the transmission output elements may not coincide. In other words, the rotational axes may be parallel to one another and may be spaced apart from one another. Alternatively, the rotational axes of the transmission output elements may coincide. In other words, the rotational axis of one transmission output element may or may coincide with a rotational axis of at least one other transmission output element. Further, the rotational axes of the transmission output elements may be parallel to or inclined to the rotational axis of the transmission input element.

Further, the apparatus may comprise the gear unit configured to transfer a rotational movement of the transmission input element into a rotational movement of each one of the transmission output elements around their rotational axis. In other words, upon rotation of the transmission input element around the further rotational axis, each one of the transmission output elements may be rotated around their respective rotational axis, thereby actuating the associated screw tensioning device. Accordingly, the gear unit may be configured to transfer the input torque applied to the transmission input element into an output torque applied to each one of the transmission output elements. The input torque may have a direction which coincides with the further rotational axis of the transmission input element. At each transmission output element, the output torque may have a direction which coincides with the rotational axis of the respective transmission output element. The rotational actuation of the transmission input element may be caused or induced by the input torque applied to the transmission input element by means of the tool or any other rotational actuator.

Specifically, the gear unit may be configured such that, upon rotational actuation of the transmission input element, a rotational speed of the transmission input element around the further rotational axis, i.e. an absolute value thereof, is higher compared to a rotational speed of the transmission output element around their respective rotational axis, i.e. an absolute value thereof. By such a configuration, although the input torque is divided or partitioned into at least two output torques applied to different transmission output elements and thus to different screw tensioning devices, the absolute value of the output torques may be increased. Accordingly, for actuating the at least two screw tensioning devices, a minimal input torque to be applied to the transmission input element may be decreased such that the apparatus may be actuated by means of a manual or electric screwdriver.

In a further development, the apparatus may be configured for being operated in an engaged operating state, in which the gear unit is configured to transfer a rotational movement of the transmission input element, i.e. around the further rotational axis, into a rotational movement of each one of the transmission output elements around their rotational axis. In other words, in the engaged state, the transmission input element may be coupled to each one of the transmission output elements in a torque-transmitting manner so as to translate the input torque into the output torque acting on the transmission output elements. Thus, a torque-transmitting connection between the transmission input element and each one of the transmission output elements is established for rotationally actuating the transmission output elements around their rotational axis. In the engaged state, as a result, by actuating the transmission input element, the transmission output elements may be simultaneously rotated.

Further, the apparatus may be configured for being operated in a disengaged operating state, in which, upon rotation of the transmission input element, none of the transmission output elements is rotated around its rotational axis. In this state, the transmission input element may be decoupled from each one of the transmission output elements. In other words, in the disengaged operating state, the torque-transmitting connection between the transmission input element and the transmission output elements may be released such that the input torque is not translated into the output torque acting on the transmission output elements. As a result, upon rotationally actuating the transmission input element in the disengaged operating state of the apparatus, none of the transmission output elements is exerted or subjected to the output torque and thus none of the screw tensioning devices is actuated. In other words, in the disengaged operating state of the apparatus, the gear unit may be in an idle state, in which the input torque applied to the transmission input element is not transferred to any one of the transmission output elements.

In a further development, the gear unit comprises a central gear. The central gear may be coupled to the transmission input element in a torque-transmitting manner. Accordingly, the central gear may be rotatably mounted around the further rotational axis which may coincide with the longitudinal axis of the transmission input element. More specifically, the central gear may constitute or form the transmission input element or may be firmly fixed to the transmission input element. The central gear may be connected or may be connectable to each one of the transmission output elements in a torque-transmitting manner. Specifically, the central gear may be connected to each one of the transmission output elements in such a way that, when the central gear is rotated around the further rotational axis, each one of the transmission output elements rotates around its respective rotational axis.

Further, the central gear may be provided such that it is movable between an engagement position, in which a torque-transmitting connection to the transmission output elements, i.e. for rotating the transmission output elements around their respective rotational axis, is engaged, and a disengagement position, in which the torque-transmitting connection to the transmission output elements is released. When being arranged in the engagement position, the central gear may be configured to, upon rotation of the transmission input element around the further rotational axis, rotate each one of the mission output elements around their respective rotational axis. By contrast, when the central gear is positioned in its disengagement position, a rotational actuation of the transmission input element and/or the central gear may not cause the transmission output elements to rotate around their respective rotational axis.

For example, for operating the apparatus in its engaged operating state, the central gear may be positioned or moved, i.e. by the operator, into its engagement position. Accordingly, for operating the apparatus in its disengaged operating state, the central gear may be positioned or moved, i.e. by an operator, into its disengagement position. Further, the central gear may be mounted and supported in the apparatus such that it is preloaded, i.e. by means of a spring element, towards its engagement position or its disengagement position.

In a further development, the gear unit may be configured to selectively transfer a rotational movement of the transmission input element into a rotational movement of at least one of the transmission output elements. In other words, the gear unit may be configured to selectively set which one of the transmission output elements is rotated upon rotational actuation of the transmission input element. This means that the gear unit may set individually for each transmission output element, i.e. independently from the other transmission output elements, whether or not the rotational movement of the transmission input element is transferred into a rotational movement of the transmission output element. In other words, the gear unit may be configured to selectively engage or release the torque-transmitting connection, i.e. for rotationally actuating the transmission output elements around their rotational axis, between the transmission input element and the individual transmission output elements.

For doing so, the apparatus may be operated in a partially engaged operating state, in which the gear unit is configured to, for at least one transmission output element, engage the torque-transmitting connection to the transmission input element for rotational actuation of the at least one transmission output element and, for at least one other transmission output element, release the torque-transmitting connection to the transmission input element. In this operating state, the gear unit may be configured to, upon rotation of the transmission input element, rotate at least one transmission output element around its rotational axis, while at least one other transmission output element is not rotationally actuated around its rotational axis.

In a further development, the gear unit may comprise at least two intermediate gears, each of which is connected or connectable to the transmission input element and one associated transmission output element in a torque-transmitting manner. In this way, the intermediate gears may form a part of the torque-transmitting connection of the transmission output elements to the transmission input element, respectively, for rotationally actuating the transmission output elements. For doing so, each of the intermediate gears may be interposed between one transmission output element and the transmission input element. The intermediate gears may be rotatably mounted around a rotational axis which is parallel to and spaced apart from the rotational axis of the associated transmission output element. Alternatively, the rotational axis of the intermediate gears may coincide with the rotational axis of the associated transmission output element.

In a further development, each one of the at least two intermediate gears may be configured to be movable between an engagement position, in which a torque-transmitting connection between the transmission input element and the associated transmission output element is engaged, and a disengagement position, in which the torque-transmitting connection between the transmission input element and the associated transmission output element is released. In this way, by positioning the intermediate gears into its engagement or disengagement position, the apparatus is enabled to selectively establish or release the torque-transmitting connection between the transmission input element and the respective transmission output elements so as to set which one of the transmission output elements is to be rotationally actuated upon rotation of the submission input element.

Further, the apparatus may comprise at least two torque multiplier units, each of which may be engaged with one transmission output element. Further, each one of the at least two torque multiplier may be connectable to one actuating element of a screw tensioning device. Specifically, the torque multiplier unit may comprise a torque input element connected to the associated transmission output element in a torque-transmitting manner and a torque output element connectable to the actuating element of the associated screw tensioning device. Each torque multiplier unit may be configured to transform an output torque applied to the associated transmission output element into an actuating torque acting on the associated actuating element which absolute value is higher compared to the output torque.

Specifically, at least one of the at least two torque multiplier units may be equipped with a planetary gear, comprising a sun gear connected to the transmission output element, at least one planet gear supported by a carrier connected to a torque output element of the torque multiplier unit and a ring gear fixed to a housing of the apparatus in a torque-transmitting manner. By being equipped with the planetary gear, the apparatus may be provided with a compact design, while ensuring that an actuating torque to be applied to the transmission input element may be relatively small. In this way, the proposed apparatus may be actuated with an electric screw-driver.

Further, a use of the above described apparatus may be provided for simultaneously actuating at least two screw tensioning devices. Specifically, the at least two transmission output elements may be connected to one actuating element of the at least two tensioning devices, respectively, for actuating the screw tensioning devices.

To that end, a method for actuating at least two screw tensioning devices may be provided, comprising the steps of providing an above described apparatus; connecting each one of the at least two transmission output elements of the apparatus to one actuating element of the screw tensioning devices; and rotationally actuating the transmission input element of the apparatus to simultaneously actuate the screw tensioning devices. In the proposed method, an apparatus as described above is used. Accordingly, technical features which are described in connection with the apparatus may also relate and be applied to the method, and vice versa.

The method may further comprise a step of selectively actuating at least one of the screw tensioning devices by means of the apparatus. For example, for doing so, at least one of the intermediate gears of the gear unit may be positioned into its engaged position, while at least one other intermediate gear may be positioned into its disengaged position.

For example, when performing the method, after connecting the apparatus, i.e. its transmission output elements, to the actuating elements of the screw tensioning devices, the transmission input element of the apparatus may be rotationally actuated so as to simultaneously actuate the screw tensioning devices. Thereafter, the screw tensioning devices may be successively further actuated by means of the apparatus, i.e. by selectively actuating the individual screw tensioning devices.

The proposed apparatus may be used for simultaneously actuating at least two screw tensioning devices, each of which is configured for fastening and/or loosening one tensable connecting element <NUM> to a component to be tightened. The apparatus may be used in different fields of application, such as in steel constructions or engine design applications. In the following, the use of the apparatus <NUM> depicted in <FIG> for simultaneously actuating at least two screw tensioning devices <NUM> is described in more detail.

To connect a first component <NUM>, e.g. a crank case, to a second component <NUM>, e.g. a turbo charger mount, using an apparatus <NUM> together with four screw tensioning devices <NUM> as shown in <FIG>, the second component <NUM> is positioned next to the first component <NUM> and four connecting elements <NUM> in the form of screws are guided through respective holes in the second component <NUM> and connected to the first component <NUM> by means of a threaded connection. As a result, the connecting elements <NUM> extend from a side of the second component <NUM> which faces away from the first component <NUM>. A nut <NUM> is screwed on each connecting element <NUM> from the second end <NUM> of the connecting element <NUM> which is arrange opposite to the first end <NUM> of the connecting element <NUM> positioned in and fastened to the first component <NUM>.

Then, each connecting element <NUM> is engaged with one respective screw tensioning device <NUM> such that the second end <NUM> of the connecting element <NUM> is fixed to the engagement section of the engagement element <NUM> to establish a threaded connection between the engagement element <NUM> and the second end <NUM> of the connecting element <NUM>.

Thereafter, the apparatus <NUM> is provided and connected to the screw tensioning devices <NUM> such that each transmission output element <NUM> is connected to an actuating element <NUM> of one screw tensioning device <NUM>.

To apply a tension force to the connecting elements <NUM>, the transmission input element <NUM> is rotationally actuated by using an electric or manual screwdriver so as to simultaneously actuate the four screw tensioning devices <NUM> by rotationally actuating their actuating element <NUM> via the transmission output elements <NUM>. During this step, the apparatus <NUM> is operated in its engaged operating state, in which, upon rotation of the transmission input element <NUM>, each one of the transmission output elements <NUM> and thus each actuating element <NUM> of the screw tensioning devices <NUM> are rotated.

Upon rotationally actuating the actuating elements <NUM>, in each screw tensioning device <NUM>, the pistons <NUM> is translationally actuated relative to the engagement element <NUM> in a direction facing away from the second component <NUM>. By moving the piston <NUM> in this direction, i.e. upwards, the piston portion <NUM> of the fluid chamber <NUM> decreases and hydraulic fluid is pushed therefrom into the effective portion <NUM> of the fluid chamber <NUM> via the connecting bores <NUM>. As a result, the effective portion <NUM> increases in volume, thereby exerting a pressure on the engagement element <NUM> which moves the same along the longitudinal axis <NUM> of the device <NUM> in respect to the support element <NUM>. Accordingly, a distance between the engagement element <NUM> and the first and the second component <NUM>, <NUM> increases, thereby tensioning and thus lengthening the connecting element <NUM>.

This step is performed until a predefined pressure in one of the fluid chambers <NUM> of the screw tensioning devices <NUM> is reached.

Then, in a subsequent step, each one of the screw tensioning devices <NUM> is individually and successively operated so as to ensure proper assembly of the respective connecting elements <NUM>. During this step, the apparatus <NUM> is operated in its partially engaged operating state in which, upon rotation of the transmission input element <NUM>, only a single one of the transmission output elements <NUM> and thus only one actuating element <NUM> of one screw tensioning device <NUM> is rotated. Specifically, in this step, each one of the screw tensioning devices <NUM> is operated until a predefined maximum pressure in its fluid chamber <NUM> is reached so as to set a predefined tensioned condition of the connecting elements <NUM>.

In this tensioned condition of connecting element <NUM>, for retaining the tension on the connecting element <NUM>, the nut <NUM> is further tightened on the connecting element until the nut <NUM> abuts on the second component <NUM>. Alternatively, for loosening the connecting elements, the nut <NUM> may be unscrewed. This is performed by reaching through openings in the support element <NUM> with a tool, like a stick which end may be inserted in openings at the side of the nut <NUM> to turn the nut <NUM> on the connecting element <NUM> from the side.

Claim 1:
Apparatus (<NUM>) for simultaneously actuating at least two screw tensioning devices (<NUM>), comprising:
- a transmission input element (<NUM>) for engagement with a tool;
- at least two transmission output elements (<NUM>), each of which is connectable to one of the screw tensioning devices (<NUM>) and rotatably mounted around a rotational axis (<NUM>); and
- a gear unit (<NUM>) configured to transfer a rotational movement of the transmission input element (<NUM>) into a rotational movement of each one of the transmission output elements (<NUM>) around their rotational axis (<NUM>), wherein
the gear unit (<NUM>) comprises a central gear (<NUM>) fixed to the transmission input element (<NUM>) and connected or connectable to each one of the transmission output elements (<NUM>) in a torque-transmitting manner, wherein the central gear (<NUM>) is movable between an engagement position, in which a torque-transmitting connection to the transmission output elements (<NUM>) is engaged, and a disengagement position, in which the torque-transmitting connection to the transmission output elements (<NUM>) is released
and/or wherein
the gear unit (<NUM>) comprises at least two intermediate gears (<NUM>) connected or connectable to the transmission input element (<NUM>) and one associated transmission output element (<NUM>) in a torque-transmitting manner, wherein each one of the intermediate gears (<NUM>) is movable between an engagement position, in which a torque-transmitting connection between the transmission input element (<NUM>) and the associated transmission output element (<NUM>) is engaged, and an disengagement position, in which the torque-transmitting connection between the transmission input element (<NUM>) and the associated transmission output element (<NUM>) is released.