The invention relates to a device, a method and a use for a transmission of rotational energy. Especially, the invention belongs to the field of a transmission with an effective degree of efficiency. It is a main aspect of the invention that the efficiency of the transmission of rotational energy is increased. Especially, rotational energy can transmitted in the field of propulsion machines, however, any other technical field in which the transmission of rotational energy is necessary or needed, the invention can by used. Examples are energy generating systems (wind turbines), means of transport and any energy production in which rotational energy in the form of a rotating shaft can be provided.

The object is achieved according to the subject-matter of the independent claims. Advantageous embodiments are the subject-matter of the respective dependent claims and the description.

The invention provides a device, a method and a use for transmission of rotational energy.

The invention provides a device which comprises - a first shaft which can be connected with an output shaft of a drive unit,

- a second shaft that is rotationally supported around the first shaft such that the second shaft can be moved around the first shaft, wherein the second shaft is in operative connection with the first shaft such that the second shaft can be driven around its axis by movement of the first shaft around its axis, and

- a third shaft in operative connection with the second shaft.

According to the invention the torque and speed from the drive unit can be transmitted by the three shafts in such a way that each of the shafts can rotate around their own axis but have additional movement with regard to the relationship between the first shaft and second shaft as well as the second shaft and the third shaft, that is the second shaft can have an additional movement in the form that the second shaft moves around the axis of the first shaft and/or third shaft. The second shaft can be moved around a closed line around the axis of the first and/or third shaft.

By the additional movement of the second shaft, each of the elements, e.g. sprocket(s), rotational element(s) etc., which are position at the second shaft, can be moved around the first shaft and/or third shaft. Especially the movement of the second shaft around the first shaft and/or third shaft is a circle.

In a preferred embodiment a support for the first shaft and the second shaft is provided so that the second shaft moves around the first shaft in a pre-determined manner defined by the support, preferably in such a manner that movement of the second first shaft around the axis of the first shaft does not induce movement of the second shaft around its axis by the support. A support can be provided which substantially can be a rod or bar on which ends a bearing can be positioned. One bearing can be provided around one of the shafts. This is a simple manner to allow the additional movement of the second shaft around the first and/or third shaft.

In a preferred embodiment, a first rotational element is provided around the first shaft and a second rotational element is provided around the second shaft such that the second shaft can move around the axis of the first shaft when the second rotational element runs on the first rotational element. The rotational elements and/or the support provide a course for the movement of the second shaft around the first shaft. A simple manner of establishing a pre-determined course can be provided.

In a preferred embodiment, the operative connection between the first shaft and the second shaft is provided by a first pair of sprockets, wherein one of the sprockets of the first pair is connected to the first shaft and the other of the sprockets of the first pair of sprockets is connected to the second shaft, preferably one of the sprockets of the first pair of sprockets is fixed to the axle of the first shaft and the other sprocket of the first pair of sprockets is fixed to the axle of the second shaft such that the sprockets of the first pair of sprockets are in center alignment with the axles of the first and second shaft, respectively. Using sprockets is a simple manner to transmit the rotation of the first shaft to the second shaft. According to the description the term ..operative connection" encompasses the transmission of rotational energy between shafts such that by the operative connection rotation of the first shaft around its axis induces rotation of the second shaft around its axis.

In a preferred embodiment, the operative connection between the second shaft and the third shaft is provided by a second pair of sprockets, wherein one of the sprockets of the second pair of sprockets is connected to the second shaft and the other sprocket of the second pair of sprockets is connected to the third shaft, preferably one of the sprockets of the second pair of sprockets is fixed to the axle of the second shaft and the other sprocket of the second pair of sprockets is fixed to the axle of the third shaft such that the sprockets of the second pair of sprockets are in center alignment with the axles of the second and third shaft, respectively. Using sprockets is a simple manner to transmit the rotation of the second shaft to the third shaft. According to the description the term ..operative connection" encompasses the transmission of rotational energy between shafts such that by the operative connection rotation of the second shaft around its axis induces rotation of the third shaft around its axis.

In a preferred embodiment, at least two of the sprockets for the operative connection of the first shaft and the second shaft and/or for the operative connection of the second shaft and the third shaft are directly or indirectly in engagement with each other, preferably the sprockets are in engagement with a chain so that rotation of one of the sprockets around the axis of the respective shaft can be transmitted such that a corresponding sprocket can be rotated around the axis of the perspective shaft the sprocket is arranged onto.

By means of sprockets which rotate and move around a closed line around a shaft onto which a further sprocket which are directly or indirectly in engagement which is other, the two movements can be transferred into an exclusively rotation of the third shaft around its axis.

In a preferred embodiment, the sprockets of the first pair of sprockets have the same or a different diameter. A transmission can be easily established by using diameters of the sprockets that are required for the respective application.

In a preferred embodiment, the sprockets of the second pair of sprockets have the same or a different diameter. A transmission can be easily established by using diameters of the sprockets that are required for the respective application. In a preferred embodiment, the diameter of the first pair and the second pair of sprockets are the same or the diameter of the first pair and the second pair of sprockets differ, preferably, the diameter of the sprockets of the first pair of sprockets is bigger than the diameter of the sprockets of the second pair. The diameter can be chosen in accordance with the application the device is used for.

In a preferred embodiment, at least one of the rotational elements is a gear and/or the diameter of the rotational elements is bigger than the diameter of the sprockets of the first and/or second pair of sprockets. The diameter of the rotational elements can be chosen such that a simple movement of the second shaft around the axis of the first shaft can be realized.

In a preferred embodiment, the second shaft is positioned in a housing, preferably the first shaft and the third shaft are at least partially positioned in the housing. An easy to handle device can be realized by positioning the shafts at least partially in a housing. Preferably at least one lid can be provided in the region or area of the third shaft to establish a possibility of access to the device.

In a preferred embodiment, the first shaft and the third shaft are positioned in center alignment with regard to the axes of the first and the third shaft. Doing so can allow for a smooth transmission so that the rotational energy due to the movement of the second shaft around the first shaft can be substantially fully transmitted into the exclusive rotational movement of the third shaft.

The invention provides a method for transmitting rotational energy comprising the steps of providing

- a first shaft which can be connected with an output shaft of a drive unit,

- a second shaft in operative connection with the first shaft, and

- a third shaft in operative connection with the second shaft, wherein the method further comprises the step of providing a rotational support such that the second shaft moves around the axis of the first shaft when transmitting rotational energy.

The invention provides a use of a device for transmission of rotational energy comprising

- a first shaft which can be connected with an output shaft of a drive unit,

- a second shaft which is in operative connection with the first shaft such that the second shaft can be driven around its axis by movement of the first shaft around its axis, and - a third shaft in operative connection with the second shaft such that the third shaft can be driven around its axis by movement of the second shaft around its axis, wherein a support is used, the support providing rotational relationship of the second shaft around the axis of the first shaft such that the second shaft can be moved around the axis of the first shaft.

The device for transmission of rotational energy can and will also be referred to as a gear mechanism in the description and the claims.

The first shaft can and will also be referred to as an input shaft in the description and the claims. The input shaft can be connected with an output shaft of a drive unit.

The second shaft can and will also be referred to as an intermediate shaft in the description and the claims. The intermediate shaft is rotationally supported around the input shaft (first shaft) such that the intermediate shaft (second shaft) can be moved around the input shaft (first shaft). The intermediate shaft (second shaft) is in operative connection with the input shaft (first shaft) such that the intermediate shaft (second shaft) can be driven around its axis by movement of the input shaft (first shaft) around its axis.

The third shaft can and will also be referred to as an output shaft in the description and the claims. The output shaft (third shaft) is in operative connection with the intermediate shaft (second shaft).

The device (the gear mechanism) according to the invention preferably has at least one intermediate shaft (at least one second shaft).

The intermediate shaft (second shaft) preferably is parallel and offset from the input shaft (first shaft).

The intermediate shaft (second shaft) is in operative connection with the input shaft (first shaft) such that the intermediate shaft (second shaft) can be driven around its axis by movement of the input shaft (first shaft) around its axis by way of at least one force transmitting member connecting the input shaft (the first shaft) and the intermediate shaft (second shaft).

The at least one force transmitting member (for example a chain) is configured for rotating the intermediate shaft (second shaft) in the same direction as the input shaft (first shaft). The intermediate shaft (second shaft) in a preferred embodiment is mating with at least one fixed mating member (for example a first rotational element).

In a preferred embodiment the intermediate shaft (second shaft) is rotatably connected to a rotatable support member (for example a support).

In a preferred embodiment the support member (for example the support) is rotatable about the input shaft (the first shaft).

In a preferred embodiment the device (the gear mechanism) according to the invention has at least one further force transmitting member (for example a chain) connecting the output shaft (third shaft) and the at least one intermediate shaft (second shaft). This is a means of providing the operative connection of the output shaft (third shaft) with the intermediate shaft (second shaft) in a preferred embodiment.

In a preferred embodiment the at least one further force transmitting member (for example a chain) is configured for rotating the output shaft (the third shaft) in the same direction as the at least one intermediate shaft (second shaft).

In a preferred embodiment the gear mechanism (the device) comprises two intermediate shafts (two second shafts).

In a preferred embodiment the two intermediate shafts (the two second shafts) are positioned on opposite sides of the input shaft (the first shaft).

In a preferred embodiment the at least one intermediate shaft (the at least one second shaft) comprises at least one intermediate shaft output member (for example a sprocket) configured for rotating with the intermediate shaft (the second shaft) and mating with the at least one fixed mating member (for example a first rotational element).

In a preferred embodiment the at least one intermediate shaft output member and the at least one fixed mating member are external gears.

In a preferred embodiment the support member is rotationally supported by the input shaft (the first shaft). In a preferred embodiment the input shaft (the first shaft) extends through the rotatable support member.

In a preferred embodiment the intermediate shaft (the second shaft) extends through the rotatable support member. In a preferred embodiment the input shaft (first shaft) extends through a fixed mating member.

In a preferred embodiment the output shaft (third shaft) extends through a fixed mating member.

In a preferred embodiment the gear mechanism (the device) comprises a housing where the input shaft (the first shaft) extends into the housing and the output shaft (third shaft) extends out of the housing.

In a preferred embodiment the at least one fixed mating element is fixed to the housing.

The input shaft (the first shaft) of the gear mechanism (the device) according to the invention can be a solid shaft, but can also be a pipe. The input shaft (first shaft) can be of metal, but can also be of other materials, like plastic materials, composite materials or even wood.

The input shaft (first shaft) can have a continuous outer shape, for example the outer shape of a round cylinder. Other outer shapes of the input shaft (first shaft) are feasible too, like for example polygonal outer shapes. Instead of a continuous outer shape, the input shaft (first shaft) also can have interruptions of a continuous outer shape, for example can have steps inbetween sections, whereby in a preferred embodiment the individual section of the input shaft (first shaft) that borders the step has a continuous shape. Steps can be used to position bearings for example.

The intermediate shaft (second shaft) of the gear mechanism according to the invention can be a solid shaft, but can also be a pipe. The intermediate shaft (second shaft) can be of metal, but can also be of other materials, like plastic materials, composite materials or even wood.

The intermediate shaft (second shaft) can have a continuous outer shape, for example the outer shape of a round cylinder. Other outer shapes of the intermediate shaft (second shaft) are feasible too, like for example polygonal outer shapes. Instead of a continuous outer shape, the intermediate shaft (second shaft) also can have interruptions of a continuous outer shape, for example can have steps inbetween sections, whereby in a preferred embodiment the individual section of the intermediate shaft (second shaft) that borders the step has a continuous shape. Steps can be used to position bearings for example. In a preferred embodiment at least one intermediate shaft (second shaft) is provided that is parallel and offset from the input shaft (first shaft). In a preferred embodiment, at least two, preferably at least three, preferably at least four, preferably at least five intermediate shafts (second shafts) are provided. It is believed that in increasing the number of shafts the force is better distributed and the balance is better. Increasing the number of shafts might even reduce the friction inside the gear mechanism. In a preferred embodiment, several, preferably the majority, more preferably all intermediate shafts (second shafts) provided are of the same shape and/or size.

In a preferred embodiment at least one force transmitting member connecting the input shaft (first shaft) and the at least one intermediate shaft (second shaft) is provided. In a preferred embodiment, for each intermediate shaft (second shaft) provided an individual force transmitting member is provided. Designs might be feasible, where one force transmitting member connects several, preferably the majority, preferably all intermediate shafts (second shafts) with the input shaft, for example a chain or a belt. While it is considered feasible within a preferred embodiment to have one force transmitting member connect several, preferably the majority, preferably all intermediate shafts (second shafts) with the input shaft (first shaft), by way of this force transmitting member being a chain or a belt, in an even more preferred embodiment a chain or a belt is used to implement the preferred embodiment, wherein for each intermediate shaft (each second shaft) provided an individual force transmitting member is provided. Hence in a preferred embodiment one belt or one chain is provided per intermediate shaft (second shaft). Independent of the type of force transmitting member used in a preferred embodiment, for each intermediate shaft (second shaft) provided an individual force transmitting member is provided.

In a preferred embodiment the force transmitting member can be a chain or a belt. The belt can be a friction belt or can be a toothed belt. The chain can be a metallic chain or can be a chain from a different material. In a preferred embodiment, the chain is a roller chain, preferably a chain of the type 04B1. In a preferred embodiment, the chain pitch is between 1mm and 50mm, preferably between 1mm and 40mm, preferably between 1mm and 30mm, preferably between 1mm and 20mm, preferably between 1mm and 10mm, preferably the chain pitch is 6mm. In a preferred embodiment, the chain width is between 1mm and 50mm, preferably between 1mm and 40mm, preferably between 1mm and 30mm, preferably between 1mm and 20mm, preferably between 1mm and 10mm, preferably the chain width is 7mm.

In one alternative of the invention a flexible drive shaft can be used as force transmitting member. A flexible drive shaft is understood to be a device for transmitting rotary motion between two objects which are not fixed relative to one another. It consists of a rotating wire rope or coil which is flexible but has some torsional stiffness. The flexible drive shaft may be connected with one end to the end of the input shaft and with the other end with an end of the intermediate shaft thereby rotating the intermediate shaft in the same direction as the input shaft.

In a further alternative of the invention a force transmitting member used as part of the invention can comprise a universal joint (often also referred to as universal coupling, U- joint, Cardan joint, Spicer or Hardy Spicer joint, or Hooke's joint). An universal joint is considered to be a joint or coupling connecting rigid rods whose axes are inclined to each other, and is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges located close together, oriented at 90° to each other, connected by a cross shaft. In a preferred embodiment, the force transmitting member comprises two universal joints with a rod arranged inbetween the two universal joints. In such an embodiment, the first universal joint could be connected with the intermediate shaft (second shaft) on one side and the rod on the other side, while the rod is connected to the second universal joint on its other side, the second universal joint being connected to the input shaft (first shaft) on its respective other side. Thereby the force transmitting member can rotate the input shaft (first shaft) in the same direction as the intermediate shaft (second shaft).

In a preferred embodiment two intermediated shafts are provided, namely a first intermediate shaft and a second intermediate shaft, whereby

• a force transmitting is connected to the input shaft and the first intermediate shaft, wherein the force transmitting member is configured for rotating the first intermediate shaft in the same direction as the input shaft and

• an auxiliary force transmitting member is connected to the first intermediate shaft and the second intermediate shaft, wherein the auxiliary force transmitting member is configured for rotating the second intermediate shaft in the same direction as the first intermediate shaft.

Hence while in a preferred embodiment the number of force transmitting members provided equals the number of intermediate shafts, designs are also feasible, where several intermediate shafts are present, but only one or some of these intermediate shafts is connected to a force transmitting member and other intermediate shafts are rotated by way of one or more auxiliary force transmitting members arranged between such an intermediate shaft and an intermediate shaft that is driven by an auxiliary force transmitting member.

The auxiliary force transmitting member preferably is a chain or a belt.

According to the invention the at least one force transmitting member is configured for rotating the at least one intermediate shaft in the same direction as the input shaft. For an additional force transmitting member, for example the auxiliary force transmitting member this is for example achieved by a belt or a chain that is set around one intermediate shaft and driven by the intermediate shaft and runs onto a further intermediate shaft in a straight line from the intermediate shaft and runs around the further intermediate shaft to then rotate the further intermediate shaft in the same direction as the intermediate shaft.

In a preferred embodiment the at least one intermediate shaft (second shaft) is mating with at least one fixed mating member. In a preferred embodiment, the fixed mating member is provided by way of it being connected to or arranged on or being part of a housing of the gear mechanism (of the device) that remains stationary in comparison to a movement of the intermediates shaft (second shaft) and/or the input shaft (first shaft). In a preferred embodiment the mating between the intermediate shaft (second shaft) and the fixed mating member is provided by a gear wheel provided on the intermediate shaft (second shaft) that meshes with a fixed gear wheel that provides the fixed mating member. In a preferred embodiment, the gearwheel provided on the intermediate shaft (second shaft) and the fixed gear wheel, it mashes with, (the fixed mating member) are externally threaded gear wheels. The gear wheel provided on the intermediate shaft (second shaft) hence runs around the outside of the fixed gear wheel (the fixed mating member). However, designs are also feasible, where the fixed gear wheel (the fixed mating member) is an internally threaded gear wheel as they are known from planetary gear mechanisms. In such a design, the gear wheel provided on the intermediate shaft (the second shaft) hence runs around the inward facing thread of the fixed gear wheel (the fixed mating member). The mating of the intermediate shaft with the at least one fixed mating member can also be provided by other means. The intermediate shaft can have a wheel that roles along a curved, preferably circular outer or inner surface of the fixed mating member.

The fixed mating member preferably is fixedly attached to a housing of the gear mechanism (the device). The fixed mating member can be an element of the housing that is made as one piece with the housing, for example a shoulder of the housing. The fixed mating member can be fixedly, but releasably attached to the housing, for example by way of bolts and nuts or by way of screws and threads or by way of pins or by way of rivets. The fixed mating member can also be fixed to the housing by way of welding, gluing, interference fit with a step of the housing.

According to the invention, the intermediate shaft (second shaft) is rotatably connected to a rotatable support member. The rotatable connection between the intermediate shaft and the rotatable support member can for example be by way of ball bearings, preferably by two-row ball bearings or by needle bearings or by way of a bush or by way of an electromagnetic field or by way of a magnetic field or by way of high pressure oil sleeves.

In a preferred embodiment the support member is made of aluminum, cast iron or composite materials.

In a preferred embodiment, the support member is a block. In a preferred embodiment, the gear mechanism has one support member and for those embodiments of the invention that have several intermediate shafts (second shafts), each intermediate shaft (second shaft) is rotatably connected to the one support member.

In a preferred embodiment, the support member is not a disc, but a block. The block may be rectangular, preferably with rounded ends, e.g. end surfaces that form a section of the outer surface of a cylinder. The block preferably is a rectangular block if two intermediate shafts (second shafts) are provided. In such a design, preferably each of the two intermediate shafts would be rotatably connected to the block at one of the ends such that at each end of the block one intermediate shaft would be connected to the block. The block may be of star shape, for example of the shape of a three-legged star, in an embodiment that has three intermediates shafts (second shafts), whereby each intermediate shaft (second shaft) would be rotatably connected to the end of one of the legs respectively.

In a preferred embodiment, if the length of the support member is understood to be the extend that the support member has in the direction radial to the intermediate shaft and if the width of the support member is understood to be a direction perpendicular to the length, but also radial to the input shaft and the height of the support member is understood to be the direction perpendicular to the length and perpendicular to the width, but co-axial or parallel to the axial extend of the input shaft, in such a set of coordinate it is preferred if the width and/or the height of the support member stay the same for the majority of the extend in the direction of the length of the support member. Preferably the width and/or the height of the support member only changes at the end of the support member. This design rule can be applied to a support member that has the shape of a block or can be applied to a support member that is star shaped, whereby the design rule would be applied for each leg of the star.

In a preferred embodiment, the support member is arranged on one side of the force transmitting member. In a preferred embodiment any force transmitting member present that connects the input shaft to the intermediate shaft is provided on one side of the support member. In a preferred embodiment the support member does not have a protrusion that extends from one side of a force transmitting member into the direction of the other side of the force transmitting member. In a preferred embodiment the support block is arranged on one side of the force transmitting member and does not encapsulate the force transmitting member. In a preferred embodiment the support member is arranged on one side of all force transmitting members present that connects the input shaft to the intermediate shaft and does not encapsulate any force transmitting member present that connects the input shaft to the intermediate shaft.

The output shaft (third shaft) of the gear mechanism (the device) according to the invention can be a solid shaft, but can also be a pipe. The output shaft (the third shaft) can be of metal, but can also be of other materials, like plastic materials, composite materials or even wood.

The output shaft (the third shaft) can have a continuous outer shape, for example the outer shape of a round cylinder. Other outer shapes of the output shaft (the third shaft) are feasible too, like for example polygonal outer shapes. Instead of a continuous outer shape, the output shaft (the third shaft) also can have interruptions of a continuous outer shape, for example can have steps inbetween sections, whereby in a preferred embodiment the individual section of the output shaft (the third shaft) that borders the step has a continuous shape. Steps can be used to position bearings for example.

In a preferred embodiment, the output shaft (the third shaft) is arrange co-axial or parallel to the input shaft (the first shaft). In a preferred embodiment, the output shaft (the third shaft) is arranged at a distance from the input shaft (the first shaft) when viewed in the direction of the longitudinal axis of the input shaft (the first shaft). Preferably the output shaft (the third shaft) is not designed as a hollow shaft that contains the or parts of the input shaft (the first shaft). Preferably the input shaft (the first shaft) is not designed as a hollow shaft that contains the or parts of the output shaft (the third shaft).

In a preferred embodiment at least one further force transmitting member connecting the intermediate shaft (second shaft) and the output shaft (third shaft) is provided. In a preferred embodiment, for each intermediate shaft (second shaft) provided an individual further force transmitting member is provided. Designs might be feasible, where one further force transmitting member connects several, preferably the majority, preferably all intermediate shafts (second shafts) with the output shaft (third shaft), for example a chain or a belt. While it is considered feasible within a preferred embodiment to have one further force transmitting member connect several, preferably the majority, preferably all intermediate shafts (second shafts) with the output shaft (third shaft), by way of this further force transmitting member being a chain or a belt, in an even more preferred embodiment a chain or a belt is used to implement the preferred embodiment, wherein for each intermediate shaft (each second shaft) provided an individual further force transmitting member is provided. Hence in a preferred embodiment one belt or one chain is provided per intermediate shaft (second shaft). Independent of the type of further force transmitting member used in a preferred embodiment, for each intermediate shaft (second shaft) provided an individual further force transmitting member is provided.

In a preferred embodiment the further force transmitting member connecting the intermediate shaft (second shaft) and the output shaft (third shaft) can be a chain or a belt. The belt can be a friction belt or can be a toothed belt. The chain can be a metallic chain or can be a chain from a different material. In a preferred embodiment, the chain is a roller chain, preferably a chain of the type 04B1. In a preferred embodiment, the chain pitch is between 1mm and 50mm, preferably between 1mm and 40mm, preferably between 1mm and 30mm, preferably between 1mm and 20mm, preferably between 1mm and 10mm, preferably the chain pitch is 6mm. In a preferred embodiment, the chain width is between 1mm and 50mm, preferably between 1mm and 40mm, preferably between 1mm and 30mm, preferably between 1mm and 20mm, preferably between 1mm and 10mm, preferably the chain width is 7mm.

In one alternative of the invention a flexible drive shaft can be used as further force transmitting member connecting the intermediate shaft (second shaft) and the output shaft (third shaft). A flexible drive shaft is understood to be a device for transmitting rotary motion between two objects which are not fixed relative to one another. It consists of a rotating wire rope or coil which is flexible but has some torsional stiffness. The flexible drive shaft may be connected with one end to the end of the output shaft and with the other end with an end of the intermediate shaft thereby rotating the intermediate shaft in the same direction as the output shaft.

In a further alternative of the invention a further force transmitting member connecting the intermediate shaft (second shaft) and the output shaft (third shaft) used as part of the invention can comprise an universal joint (often also referred to as universal coupling, U-joint, Cardan joint, Spicer or Hardy Spicer joint, or Hooke's joint). An universal joint is considered to be a joint or coupling connecting rigid rods whose axes are inclined to each other, and is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges located close together, oriented at 90° to each other, connected by a cross shaft. In a preferred embodiment, the further force transmitting member comprises two universal joints with a rod arranged inbetween the two universal joints. In such an embodiment, the first universal joint could be connected with the intermediate shaft (second shaft) on one side and the rod on the other side, while the rod is connected to the second universal joint on its other side, the second universal joint being connected to the output shaft (third shaft) on its respective other side. Thereby the force transmitting member can rotate the output shaft (third shaft) in the same direction as the intermediate shaft (second shaft). In a preferred embodiment where the gear mechanism (the device) has a housing, the input shaft extends into the housing from one side of the housing and the output shaft extends out of the housing on a different side of the housing.

In a preferred embodiment the support member is rotatable about the input shaft (the first shaft). In a preferred embodiment, the input shaft (the first shaft) is rotatably supported inside the support member, for example by way of a bearing arranged in a recess of the support member, whereby the input shaft (the first shaft) is supported by the bearing. Designs are also feasible where instead of the bearing a bush is provided. In a preferred embodiment the input shaft (the first shaft) extends through the support member

In a preferred embodiment, the gear mechanism (the device) comprises two intermediate shafts (two second shafts).

In a preferred embodiment, the two intermediate shafts (the two second shafts) are positioned on opposite sides of the input shaft.

In a preferred embodiment, the input shaft (the first shaft) comprises at least one input shaft output member configured for rotating with the input shaft. In a preferred embodiment the input shaft output member is an external gear. In a preferred embodiment, the input shaft output member is made as one piece with the input shaft (the first shaft), for example by way of CNC-machining. In a preferred embodiment the input shaft output member is a separate part to the input shaft (the first shaft), but fixedly attached to the input shaft (the first shaft) by way of screws, wedges, gluing, welding or interference fit.

In a preferred embodiment the input shaft output member is made from metal, plastic or wood. In a preferred embodiment the input shaft output member is made from the same material as the input shaft.

In a preferred embodiment, the at least one intermediate shaft (the second shaft) comprises an intermediate shaft input member configured for rotating with the intermediate shaft. In a preferred embodiment, the intermediate shaft input member is an external gear. In a preferred embodiment, the intermediate shaft input member is made as one piece with the intermediate shaft (the second shaft), for example by way of CNC-machining. In a preferred embodiment the intermediate shaft input member is a separate part to the intermediate shaft (the second shaft), but fixedly attached to the intermediate shaft (the second shaft) by way of screws, wedges, gluing, welding or interference fit. In a preferred embodiment the intermediate shaft input member is made from metal, plastic or wood. In a preferred embodiment the intermediate shaft input member is made from the same material as the intermediate shaft.

In a preferred embodiment, the at least one intermediate shaft (the second shaft) comprises at least one intermediate shaft output member configured for rotating with the intermediate shaft (the second shaft) and mating with the at least one fixed mating member. In a preferred embodiment, the at least one intermediate shaft output member and the at least one fixed mating member are external gears. In a preferred embodiment, the intermediate shaft output member is made as one piece with the intermediate shaft (the second shaft), for example by way of CNC-machining. In a preferred embodiment the intermediate shaft output member is a separate part to the intermediate shaft (the second shaft), but fixedly attached to the intermediate shaft (the second shaft) by way of screws, wedges, gluing, welding or interference fit.

In a preferred embodiment the intermediate shaft output member is made from metal, plastic or wood. In a preferred embodiment the intermediate shaft output member is made from the same material as the intermediate shaft (the second shaft).

In a preferred embodiment the intermediate shaft (the second shaft) extends through the rotatable support member. In a preferred embodiment a bearing is arranged within the support member with the outer ring of the bearing being connected to the support member and arranged in a recess or a hole of the support member, while the intermediate shaft (the second shaft) is connected to the inner ring of the bearing.

In a preferred embodiment, the intermediate shaft (the second shaft) comprises at least one further intermediate shaft output member configured for rotating with the intermediate shaft. In a preferred embodiment the further intermediate shaft output member is an external gear. In a preferred embodiment, the further intermediate shaft output member is made as one piece with the intermediate shaft (the second shaft), for example by way of CNC-machining. In a preferred embodiment the further intermediate shaft output member is a separate part to the intermediate shaft (the second shaft), but fixedly attached to the intermediate shaft (the second shaft) by way of screws, wedges, gluing, welding or interference fit.

In a preferred embodiment the further intermediate shaft output member is made from metal, plastic or wood. In a preferred embodiment the further intermediate shaft output member is made from the same material as the intermediate shaft.

In a preferred embodiment, the output shaft (the third shaft) comprises an output shaft input member configured for rotating with the output shaft. In a preferred embodiment, the output shaft input member is an external gear. In a preferred embodiment, the output shaft input member is made as one piece with the output shaft (the third shaft), for example by way of CNC-machining. In a preferred embodiment the output shaft input member is a separate part to the output shaft (the third shaft), but fixedly attached to the output shaft (the third shaft) by way of screws, wedges, gluing, welding or interference fit.

In a preferred embodiment the output shaft input member is made from metal, plastic or wood. In a preferred embodiment the output shaft input member is made from the same material as the output shaft.

In a preferred embodiment the further force transmitting member meshes with the further intermediate shaft output member and with the output shaft input member, especially in the embodiments where the further force transmitting member is a chain.

In a preferred embodiment the output shaft (the third shaft) extends through a fixed mating member. In a preferred embodiment, the at least one intermediate shaft (the third shaft) is mating with this fixed mating member. In a preferred embodiment, the fixed mating member is provided by way of it being connected to or arranged on or being part of a housing of the gear mechanism (the device) that remains stationary in comparison to an movement of the intermediates shaft (the second shaft) and/or the output shaft (the third shaft). In a preferred embodiment the mating between the intermediate shaft (the second shaft) and the fixed mating member is provided by a gear wheel provided on the intermediate shaft (the second shaft) that meshes with a fixed gear wheel that provides the fixed mating member. In a preferred embodiment, the gear wheel provided on the intermediate shaft (the second shaft) and the fixed gear wheel, it mashes with, (the fixed mating member) are externally threaded gear wheels. The gear wheel provided on the intermediate shaft (the second shaft) hence runs around the outside of the fixed gear wheel (the fixed mating member). However, designs are also feasible, where the fixed gear wheel (the fixed mating member) is an internally threaded gear wheel as they are known from planetary gear mechanisms. In such a design, the gear wheel provided on the intermediate shaft (the second shaft) hence runs around the inward facing thread of the fixed gear wheel (the fixed mating member). The mating of the intermediate shaft (the second shaft) with the at least one fixed mating member can also be provided by other means. The intermediate shaft (the second shaft) can have a wheel that roles along a curved, preferably circular outer or inner surface of the fixed mating member.

The fixed mating member preferably is fixedly attached to a housing of the gear mechanism (the device). The fixed mating member can be an element of the housing that is made as one piece with the housing, for example a shoulder of the housing. The fixed mating member can be fixedly, but releasably attached to the housing, for example by way of bolts and nuts or by way of screws and threads or by way of pins or by way of rivets. The fixed mating member can also be fixed to the housing by way of welding, gluing, interference fit with a step of the housing.

In a preferred embodiment the input shaft (the first shaft) extends through a fixed mating member. In a preferred embodiment, the at least one intermediate shaft (the second shaft) is mating with this fixed mating member. In a preferred embodiment, the fixed mating member is provided by way of it being connected to or arranged on or being part of a housing of the gear mechanism (the device) that remains stationary in comparison to an movement of the intermediates shaft (the second shaft) and/or the input shaft (the first shaft). In a preferred embodiment the mating between the intermediate shaft (the second shaft) and the fixed mating member is provided by a gear wheel provided on the intermediate shaft (the second shaft) that meshes with a fixed gear wheel that provide the fixed mating member. In a preferred embodiment, the gear wheel provided on the intermediate shaft (the second shaft) and the fixed gear wheel it mashes with (the fixed mating member) are externally threaded gear wheels the gear wheel provided on the intermediate shaft (the second shaft) hence runs around the outside of the fixed gear wheel (the fixed mating member). However, designs are also feasible, where the fixed gear wheel (the fixed mating member) is an internally threaded gear wheel as they are known from planetary gear mechanisms. In such a design, the gear wheel provided on the intermediate shaft (the second shaft) hence runs around the inward facing thread of the fixed gear wheel (the fixed mating member). The mating of the intermediate shaft (the second shaft) with the at least one fixed mating member can also be provided by other means. The intermediate shaft (the second shaft) can have a wheel that roles along a curved, preferably circular outer or inner surface of the fixed mating member.

The fixed mating member preferably is fixedly attached to a housing of the gear mechanism (the device). The fixed mating member can be an element of the housing that is made as one piece with the housing, for example a shoulder of the housing. The fixed mating member can be fixedly, but realizably attached to the housing, for example by way of bolts and nuts or by way of screws and threads or by way of pins or by way of rivets. The fixed mating member can also be fixed to the housing by way of welding, gluing, interference fit with a step of the housing.

In a preferred embodiment the gear mechanism (the device) comprises a housing where the first shaft (input shaft) extends into the housing and the third shaft (output shaft) extends out of the housing. The housing can be of metal, for example aluminum. The housing can be machined, e.g. by way of CNC-machining. The housing can be cast. The housing can have a main body and a lid that closes the main body. The housing can contain lubrication.

In a preferred embodiment the at least one fixed mating element is fixed to the housing.

In a preferred embodiment, the support member is made from Aluminum, preferably from AIMg. In a preferred embodiment, gears that are present in the gear mechanism are heat treated. The sprockets preferably are of class 04B1. In a preferred embodiment, bearings that are present are in C version. In a preferred embodiment the connections between the parts are done thermally (folding) or by cooling (liquid nitrogen). In a preferred embodiment, the metal used for the shafts is titanium steel.

In a preferred embodiment the support member has a counter weight attached to it or formed as one-piece with the support member. In a preferred embodiment the gear mechanism according to the invention has one intermediate shaft (second shaft) rotatably connected to the rotatable support member and a counter weight attached to the support member or formed as one-piece with the support member, whereby the intermediate shaft (the second shaft) is connected to the support member on one side of the longitudinal axis of the input shaft (first shaft) and/or on one side of the longitudinal axis of the output shaft (third shaft) and the counterweight is arranged on the opposite side of the longitudinal axis of the input shaft (first shaft) and/or on the opposite side of the longitudinal axis of the output shaft (third shat) such that the counter weight balances or reduces any imbalance or unbalanced mass that is introduced by the intermediate shaft (the second shaft) being connected to the support member.

In a preferred embodiment, a bearing, preferably a ball bearing or a bush bearing is provided to support the input shaft (first shaft) in the housing. In a preferred embodiment, a bearing, preferably a ball bearing or a bush bearing is provided to support the output shaft (the third shaft) in the housing.

In a preferred embodiment of those embodiments where a roller chain is provided, for example as first force transmitting member or second force transmitting member or auxiliary force transmitting member, a tensioning sprocket is provided and the chain is arranged to engage with the tensioning sprocket. The tensioning sprocket has a modified base between the teeth of the sprocket. The modified base has an engaging member for engagement with a bush of the roller chain. The modified base furthermore has radial tensioning means that apply a radially outward pointing force to the engaging member, when the engaging member is displace radially inward. The radial tensioning means can be coil springs that are arranged in radial bores of the sprocket. The tensioning sprocket can tension the roller chain and can be used to counter-act tolerances that might occur in the manufacturing of the roller chain.

In a preferred embodiment, a gear wheel provided as part of the gear mechanism according to the invention, for example an intermediate shaft output member, has radially moveable weights. In a preferred embodiment at least one of the gear wheels provided has

• a first weight moveably arranged on a first guide, the first guide being arranged to point in the radial direction, a tension means being in contact with the first weight such that the tension means is tensioned as the first weight moves radially outward along the first guide, and

• a second weight moveably arranged on a second guide, the second guide being arranged to point in the radial direction, a tension means being in contact with the second weight such that the tension means is tensioned as the second weight moves radially outward along the second guide.

The first guide and/or the second guide can be a radially arranged bar that passes through the first weight or the second weight respectively. The first guide and/or the second guide can be a radially outward pointing pair of rails with the first weight or the second weight respectively being arranged between a respective pair of rails and travelling along this pair of rails.

The tension means can be a coil spring that is arranged radially outward of the weight and is compressed as the weight moves radially outward. The tension means can be a coil spring attached to a hub of the gear wheel and attached to the weight, the coil spring being stretched as the weight moves radially outward.

In a preferred embodiment the weights of the gear wheel are arranged equally spaced over the circumference of the gear wheel. If two weights are provided, these preferably are arranged 180° apart. If three weights are provided, these are preferably arranged 120° apart etc.

Providing weights for the gear wheel can make the gear wheel act as a dynamic flywheel. A gear wheel as modified in this embodiment will have a first moment of inertia at lower turnings speeds and a second, different moment of inertia at a second, higher turning speed as the weights move outwards with increasing turning speed.

The invention is explained in more detail below by way of example using one of the exemplary embodiments shown in the figures. The figures show:

Fig. 1 a schematic view of a device for transmission of rotational energy;

Fig. 2 a side view of an embodiment of the device;

Fig. 3 a perspective view of the device according to another embodiment;

Fig. 4 shows a cross sectional view through a center of a gear mechanism.

Fig. 5 shows a cross sectional view of the plane A-A indicated in figure 4.

Fig. 6 shows a cross sectional view of the plane B-B indicated in figure 4.

Fig. 7 shows a perspective view of parts of a gear mechanism.

Fig. 8 shows a schematic sectional view of a first embodiment of the gear mechanism.

Fig. 9 shows a schematic sectional view of a second embodiment of the gear mechanism.

Fig. 10 shows a schematic side view of a modified gear wheel with the weights in a first position.

Fig. 11 shows a schematic side view of a modified gear wheel with the weights in a second position.

Fig. 12 shows a schematic side view of a modified sprocket with roller chain arranged around the sprocket.

Fig. 13 shows a schematic front view of a modified sprocket with roller chain arranged around the sprocket of Fig. 12.

A first shaft 1 can be connected to a drive shaft which outputs torque T and speed RPM from a drive unit with which it is in direct connection. The power transmission of the drive unit to the device which transmits rotational energy between first shaft 1 and a third shaft 13 is such that the first shaft 1 passes through a rotational element 2 which is realized as a fixed gear. The fixed gear is fixed to a housing 3. A sprocket 4 of a first pair of sprockets is fixed to the first shaft 1 by a solid connection to the axle of the first shaft 1. The sprocket 4 is the drive sprocket of the device / transmission system.

Also mounted on the first shaft 1 is a support 5 which has the function of a bearing element of a rotational element 6, which is realized by a gear 6 via a second shaft 9 on which the support 5 is also mounted.

Further, on the second shaft 9 further sprockets 7, 8 which are fixed to the second shaft 9 are mounted. The sprocket 7 receives the drive movement through a chain 10 which the drive receives from the sprocket 4. The consequence of this movement is the rotational movement of the gear 6, the sprocket 7, the sprocket 8 and the shaft 9.

This rotational movement is characterized by the fact that the elements rotate around their own axis which is in the center of the axis of the second shaft 9 and have additional movement in the form of an orbit (rotation) around the axis of the first shaft 1 which is in the center of the whole system.

By means of the sprockets 7, 8 which rotate and orbit and using a chain 11, the movement is transmitted to the sprocket 12 which is fixedly connected to the third shaft 13 which brings the newly obtained movement out of the housing 3 over lids 14.

The rotational-orbital movement of the sprocket 8 is substituted by the chain 11 and the sprocket 12 into an exclusively rotational movement along the axis of the third shaft 13 where it is further connected to the shaft that preforms the work.

Referring initially to figure 4, a cross-section through a gear mechanism (device) according to the invention is shown. The gear mechanism comprises an input shaft (first shaft) 1. The input shaft 1 may be connected to a rotating shaft from e.g. a motor. The gear mechanism may be housed in a housing 3, and the input shaft 1 may extend into the housing 3. To rotatably support the input shaft 1 in the housing 3, the housing 3 may be provided with an input shaft bearing 104. The input shaft bearing 104 may be one or more ball bearings, lubricated sealing rings or similar means known in the art of supporting a rotating shaft.

The gear mechanism further comprises an intermediate shaft (second shaft) 9. The illustrated embodiment comprises two intermediate shafts 9, but the gear mechanism 1 may as such comprise any number of intermediate shafts 9. In order to balance the gear mechanism, two or more intermediate shafts could be distributed evenly around the input shaft 1. E.g. two intermediate shafts 9 could be spaced apart 180° about the input shaft 1 (as in the illustrated embodiment), three intermediate shafts could be spaced apart 120° about the input shaft, etc. In order to keep the number of components (and weight) to a minimum, two intermediate shafts 9 may be preferred. The two intermediate shafts 9 of the illustrated embodiment are positioned on opposite sides of the input shaft 1. This provides a gear mechanism 1 that is balanced and e.g. vibration may be minimized. An intermediate shaft 9 is parallel and offset from the input shaft 1, i.e. the rotation axis of an intermediate shaft 9 has the same direction as the rotation axis of the input shaft 1 , but the two axes are not coincident.

A force transmitting member 10 connects the input shaft 1 and the at least one intermediate shaft 9. The force transmitting member 10 may be any member capable of rotating the intermediate shaft 9 in the same direction as the input shaft 1. If the rotation of the input shaft 1 is clockwise, the rotation of the intermediate shaft 9 is also clockwise. The force transmitting member 10 is in the illustrated embodiment a chain, but may also be a belt, a wire or any member configured for transmitting a rotational motion from one shaft to another. The force transmitting member 10 could as such be an internal gear mating with the input shaft 1 and intermediate shaft 9.

The weight of the force transmitting member 10 plays a role in the effect of the gear mechanism, and e.g. a chain may be both heavier and have less power loss when transmitting a force compared to e.g. a belt, such that a chain comprising metal links may be preferred. The force transmitting member 10 is also preferably exterior to the input shaft 1 and the intermediate shaft 9. When the force transmitting member 10 is spun by the input shaft 1, a centrifugal force is created. This centrifugal force increases the efficiency of the gear mechanism.

The illustrated embodiment comprises two intermediate shafts 9, and as such, two force transmitting members 10 connect the input shaft 1 to the two intermediate shafts

9. The force transmitting members 10 are independent of each other, and may be positioned spaced apart on the input shaft 1.

In order to transmit the rotational force from the input shaft 1 to the force transmitting member 10, the input shaft 1 may be provided with an input shaft output member 4. The input shaft output member 4 is configured for rotating with the input shaft 1, and connection with the force transmitting member 9. The input shaft output member 4 may simply be a portion of the input shaft 1, or it may be a separate member. The input shaft output member 4 may have a radius greater than the input shaft 1. The input shaft output member 4 may be fixed to the input shaft 1, and is in the illustrated embodiment an external gear configured to mate with the force transmitting member

10. An intermediate shaft 9 may correspondingly be provided with an intermediate shaft input member 7 to mate with the force transmitting member 10. The intermediate shaft input member 7 is configured for rotating with the intermediate shaft 9, and connection with the force transmitting member 10. The intermediate shaft input member 7 may simply be a portion of the intermediate shaft 9, or it may be a separate member. The intermediate shaft input member 7 may have a radius greater than the intermediate shaft 9. The intermediate shaft input member 7 may be fixed to the intermediate shaft 9, and is in the illustrated embodiment an external gear configured to mate with the force transmitting member 10.

The intermediate shaft 9 is mating with fixed mating members 2. One intermediate shaft 2 may mate with one or more mating members 2. In the first illustrated embodiment of Fig. 4, the two intermediate shafts 9 both mate with two mating members 2. The intermediate shafts 9 of the embodiment of Fig. 1 mate with the mating members 2 at distal ends of the intermediate shaft 9. The gear mechanism 1 may comprise at least one fixed mating member 2, and one or more of the at least one fixed mating member 2 may be fixed to the housing 3. The fixed mating members 2 do not rotate or move relative to the input shaft 1 and the intermediate shaft 9, and in the illustrated embodiment, the fixed mating members 2 are positioned on the inside of the housing 3. The input shaft 1 may extend through one fixed mating member 2, and more specifically, the input shaft 1 may extend through the center of a fixed mating member 2. The fixed mating members 2 are in the illustrated embodiment external gears. As the intermediate shaft 9 is rotated by the force transmitting member 10 and mates with the fixed mating members 2, the intermediate shaft 9 is consequently driven around the fixed mating members 2. The input shaft 1 is positioned in the center of one of the fixed mating members 2, and as the input shaft 1 is rotated, the intermediate shaft 9 is rotated both around itself and consequently also around the input shaft 1. This is also described and illustrated with reference to figure 5.

An intermediate shaft 9 may comprise at least one intermediate shaft output member 110 configured for rotating with the intermediate shaft 9 and mating with a fixed mating member 2. The intermediate shaft output member 110 may be an external gear, as in the illustrated embodiment. The intermediate shaft output member 110 may have a radius greater than the intermediate shaft 9, and the intermediate shaft output member 110 may be fixed to the intermediate shaft 9. The intermediate shaft output member 110 may also simply be a portion of the intermediate shaft 9. If the intermediate shaft 9 is configured for mating with two fixed mating members 2, the intermediate shaft 9 may comprise two intermediate shaft output member 110 as in the illustrated embodiment. The two intermediate shaft output members 110 are in the illustrated embodiment positioned at distal ends of the intermediate shaft 9. The intermediate shaft 9 is further rotatably connected to a rotatable support member 5. The support member 5 is configured to rotate about the input shaft 1, i.e. the support member 5 has a rotation axis that is coincident with the rotation axis of the input shaft 1. The intermediate shaft 9 is rotatably connected to the support member 5 off-center, such that when the intermediate shaft 9 is rotated about the fixed mating members 2 and input shaft 1, the support member 5 is also rotated about the input shaft 1. The support member 5 may be shaped similarly to a disc or an arm, where the at least one intermediate shaft 9 may be connected to the support member 5 at an outer periphery. The support member 5 of the illustrated embodiment is shaped similar to an arm, as shown in figure 5.

The intermediate shaft 9 may extend through the support member 5, and the intermediate shaft 9 may as such mate with fixed mating members 2 at both sides of the support member 5. The intermediate shaft 9 may be rotatably supported in the support member 5 by means of an intermediate shaft bearing 112. The intermediate shaft bearing 112 may be one or more ball bearings, lubricated sealing rings or similar means known in the art of supporting a rotating shaft.

The support member 5 is rotatable about the input shaft 1, and may also be rotatably connected to the input shaft 1. The support member 5 may comprise a bearing 113 where the input shaft 1 is rotatably supported. The input shaft 1 may as such be supported at two independent locations; at the input shaft bearing 104 on the housing 3, and at the bearing 113 of the support member 5.

The support member 5 is rotatable about the output shaft (third shaft) 13, and may also be rotatably connected to the outpt shaft 13. The support member 5 may comprise a bearing 114 where the output shaft 13 is rotatably supported. The output shaft 13 may as such be supported at two independent locations; at an output shaft bearing 115 on the housing 3, and at the bearing 114 of the support member 5.

The output shaft bearing 115 may be one or more ball bearings, lubricated sealing rings or similar means known in the art of supporting a rotating shaft.

Referring now to figure 5 and 6, a view of the plane A-A from figure 4 is shown in figure 5, and a view of the plane B-B from figure 4 is shown in figure 6. Each force transmitting member 10 is exterior to the input shaft 1 and the respective intermediate shaft 9. As the input shaft 1 of the gear mechanism is rotated in the clockwise direction D1, the intermediate shafts 9 are correspondingly rotated in the clockwise direction D2. This may be caused by the force transmitting members 10 mating with the input shaft output member 4 and the intermediate shaft input members 7. As previously mentioned, the illustrated embodiment comprises two input shaft output members 4, two force transmitting member 10, two intermediate shafts 9 and two intermediate shaft input members 7.

Because an intermediate shaft 9 mates with a fixed mating member 2 by e.g. an intermediate shaft output member 110, the intermediate shaft 9 is rotated about the input shaft 1 in the clockwise direction D3. The support member 5, being rotatably connected to the intermediate shaft 9, is thus also rotated in the clockwise direction D3. The output shaft 13 is rotated in a corresponding clockwise direction D4.

The intermediate shaft (the second shaft) comprises further intermediate shaft output member 8 configured for rotating with the intermediate shaft 9. The further intermediate shaft output member 8 is an external gear.

The output shaft (the third shaft) 13 comprises an output shaft input member 12 configured for rotating with the output shaft 13. The output shaft input member 12 is an external gear.

The further intermediate shaft output member 8 meshes with a further force transmitting member 11, which is a chain. The further force transmitting member 11 meshes with the output shaft input member 12 and rotates the output shaft 13 in the same direction as the intermediate shaft.

Referring now to figure 7, a second embodiment of a gear mechanism is shown. This embodiment comprises fewer parts than the first illustrated embodiment, and may as such be lighter and less expensive to manufacture and maintain. The gear mechanism of the second embodiment may be suited for connection to motors with a lower output power than the gear mechanism of the first embodiment, because the intermediate shafts are mating with only one fixed mating member. To avoid describing similar features and principles twice, the features and principles of the first embodiment applies to the second embodiment unless otherwise noted.

In figure 7, a part of the housing 3 is shown, the rest of the housing 3 has been removed for illustrating purposes. The gear mechanism comprises an output shaft 13, and the output shaft 13 may extend out of the housing 3 through an output shaft bearing (not shown), but in the second embodiment, the output shaft 13 may not extend through a fixed mating member. The gear mechanism thus comprises only one fixed mating member 2, and in the second embodiment the fixed mating member 2 is a circular portion of the housing 3 comprising teeth. The fixed mating member 2 is as such an external gear provided on the housing 2. The input shaft 1 extends through the center of the fixed mating member 2. Alternatively, the fixed mating member 2 could be provided on the opposite side of the support member 5, i.e. at the other distal end of the intermediate shaft 9. The output shaft 13 would thus extend through a fixed mating member 2, but the input shaft 1 would not.

Similar to the first embodiment, the intermediate shafts 9 of the second embodiment are parallel and offset from the input shaft 1. A first force transmitting member 10 connects the input shaft 1 and a first intermediate shaft 9, and a second force transmitting member 10 connects the input shaft 1 and a second intermediate shaft 9. The intermediate shafts 9 are positioned on opposite sides of the input shaft 1 and are rotatably connected to the support member 5. In the second embodiment, the support member 5 is connected to the intermediate shaft 9 generally in the middle of the intermediate shaft 9. The input shaft 11 is provided with two input shaft output members 4 configured for connection with force transmitting members 10. The intermediate shafts 9 are provided with intermediate shaft input members 7 also configured for connection with the force transmitting members 10.

The intermediate shafts 9 extend through the support member 5, and are mating with the fixed mating member 2. In the second embodiment, the intermediate shaft output members 110 are portions of the intermediate shafts 9 comprising teeth, and are as such an external gears. The intermediate shaft output members 110 have a radius that is smaller than the radius of the fixed mating member 2.

The person skilled in the art realizes that the present invention is not limited to the preferred embodiments described above. The person skilled in the art further realizes that modifications and variations are possible within the scope of the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

For the embodiments of the invention shown in Fig. 8 and 9 like parts have been designated with the same reference signs as used in Fig. 4 to 7.

In the embodiments of Fig. 8 and 9 , the intermediate shaft 9 have been shortened in comparison to the intermediate shaft 5 shown in the embodiments of Fig. 4 to 7. The embodiments of Fig. 8 and 9 hence only have one output member 110 per intermediate shaft, namely at the end of the respective intermediate shaft 9 that is closer to the input shaft 1. While the embodiment of Fig. 4 to 6 has an output member 110 at each end of the respective intermediate shaft 9 and hence also has an output member 110 closer to the output shaft 13, this output member 110 at the end of the intermediate shaft 9 that is closer to the output shaft 13 is missing in the embodiments of Fig. 8 and 9. Likewise, the embodiments of Fig. 8 and 9only have one fixed mating member 2, namely the fixed mating member 2 that surrounds the input shaft 1.

In the embodiment of Fig. 8 a flexible drive shaft is provided as further force transmitting member 11. One end of the flexible drive shaft is attached to the endface of the output shaft 13; the opposite end of the flexible drive shaft is attached to the endface of the intermediate shaft 9.

In the embodiment of Fig. 8 the support member 5 is provided with a counter weight 16.

In the embodiments of Fig. 9 the force transmitting member 11 comprises two universal joint 19 (often also referred to as universal coupling, U-joint, Cardan joint, Spicer or Hardy Spicer joint, or Hooke's joint), which in Fig. 9are symbolized by the circles with the cross in the middle. It consists of a pair of hinges located close together, oriented at 90° to each other, connected by a cross shaft. The first universal joint 19 is connected with the output shaft 13 on one side and a rod 20 on the other side. The rod 20 is connected to the second universal joint 19 on its other side, the second universal joint 19 being connected to the intermediate shaft 9 on its respective other side. Thereby the force transmitting member 11 can be rotate the output shaft 13 in the same direction as the intermediate shaft 9.

Fig. 10 and 11 show a gear wheel that could for example be used as an intermediate shaft output member 110 and that has radially moveable weights 21. The gear wheel is provided with

• a first weight 21 moveably arranged on a first guide 22, the first guide 22 being arranged to point in the radial direction, a tension means 23 being in contact with the first weight 21 such that the tension means 23 is tensioned as the first weight 21 moves radially outward along the first guide 22, and

• a second weight 21 moveably arranged on a second guide 22, the second guide 22 being arranged to point in the radial direction, a tension means 23 being in contact with the second weight 21 such that the tension means 23 is tensioned as the second weight 21 moves radially outward along the second guide 22.

The first guide 22 and the second guide 22 are a radially arranged bar that passes through the first weight 21 or the second weight 21 respectively. The tension means 23 are coil springs that are arranged radially outward of the weight 21 and are compressed as the weight 21 moves radially outward.

Fig. 12 and 13 show a tensioning sprocket 24 that can be used in preferred embodiments where a roller chain is provided, for example as first force transmitting member 10 or second force transmitting member 10. The tensioning sprocket 24 has a modified base between the teeth 25 of the sprocket 24. The modified base has an engaging member 26 for engagement with a bush 27 of the roller chain. The modified base furthermore has radial tensioning means 28 that apply a radially outward pointing force to the engaging member 26, when the engaging member 26 is displace radially inward. The radial tensioning means 28 is a coil spring that is arranged in radial bores of the sprocket 24.