Patent Description:
Use of computing devices is becoming more ubiquitous by the day. Computing devices range from standard desktop computers to wearable computing technology and beyond. One area of computing devices that has grown in recent years is the hybrid and tablet computers. Many hybrid computers include input devices that may be separated from the screen. When separated from the other components, the screen may function as a table computer.

Conventional laptop computers may have a hinge between the screen and the keyboard portions of the laptop computer that supports the screen at a variety of angles between a closed position and an open position. Conventional tablet computers lack a support to hold the tablet in an upright or angled position. Tablet computers that include a support to hold the tablet increase a thickness of the tablet to package a hinge into the frame of the tablet computer that provides sufficient strength to support the tablet computer in a variety of positions.

<CIT> describes a hinge module including a first part, a pushing element, a second part and an elastic element. The first part has a containing slot, and the pushing part is located in the containing slot and being able to move along a direction. The second part has a hinge shaft, which rotatably passes through the containing slot along an axis, so as to make the first part and the second part rotate about the axis. The elastic element is disposed in the containing slot and pushes the pushing element, and the elastic element always drives the pushing part to move along the direction, so as to make the hinge shaft to rotatably abut between the pushing part and the first part. The direction is perpendicular to the axis.

According to aspects of the present invention there is provided a device and a method as defined in the accompanying claims.

A device for controlling movement of a support includes a frame, an arm, a torque element, and a link. The arm is rotatably connected to the frame about a lateral axis. The torque element is displaced from the lateral axis in a longitudinal direction perpendicular to the lateral axis. At least part of the torque element is rotatable about a longitudinal axis. The link is connected to the arm and the torque element such that rotation of the arm about the lateral axis translates at least part of the torque element in the longitudinal direction.

In other implementations, a hinge includes a frame, an arm and a torque element that is configured to move when the arm is moved relative to the frame. The arm is rotatably connected to the frame about a lateral axis. The arm has an open position, an intermediate point, and a closed position. The torque element has an axis of rotation at a longitudinal axis that is perpendicular to the lateral axis. The torque element does more work when the arm moves between the open position and the intermediate point than between the intermediate point and the closed position.

A method of applying torque in a hinge includes rotating an arm about a lateral axis and moving a link connected to the arm. The method further includes translating a torque element in a longitudinal direction relative to a shaft, rotating the torque element about a longitudinal axis by an interaction of the torque element and the shaft, and resisting the rotation of the torque element about the longitudinal axis.

Additional features and advantages of implementations of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such implementations. The features and advantages of such implementations may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such implementations as set forth hereinafter.

In order to describe the manner in which the above-recited and other features of the disclosure can be obtained, a more particular description will be rendered by reference to specific implementations thereof which are illustrated in the appended drawings. For better understanding, the like elements have been designated by like reference numbers throughout the various accompanying figures. While some of the drawings may be schematic or exaggerated representations of concepts, at least some of the drawings may be drawn to scale. Understanding that the drawings depict some example implementations, the implementations will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:.

This disclosure generally relates to devices, systems, and methods for providing a rotatable joint between two structures. More particularly, the present disclosure relates to providing a hinge with varying resistance between a closed position and an open position. In some implementations, the hinge may allow the movement of a support arm in an electronic device. The support arm and hinge may have sufficient strength support the electronic device at any angle of the support arm between the closed position and the open position while remaining movable by a user without the aid of tools.

In some implementations, a hinge according to the present disclosure may have an increased rotational resistance, a smaller overall thickness, a more progressive resistance curve, or combinations thereof relative to conventional hinges. For example, an implementation of a hinge described herein may include a longitudinally displaced frictional element that allows a smaller thickness than a conventional hinge. In other examples, an implementation of a hinge described herein may include different resistance regions depending on the rotational position of the hinge. In yet other examples, an implementation of a hinge described herein may include a camming mechanism to progressively alter the resistance of the hinge.

<FIG> is a perspective view of an implementation of an electronic device <NUM>. While the present disclosure will describe hinges in relation to a tablet and/or hybrid computer, it should be understood that various implementations of hinges described herein may be applicable to other electronic devices, such as digital picture frames, cellular telephones (i.e., smartphones), video game consoles, videoconferencing displays, electronic readers, or other electronic devices with displays. An electronic device <NUM> includes a frame <NUM>. The frame <NUM> is rotatably connected to a support arm <NUM> about a hinge <NUM>. The hinge <NUM> may allow the support arm <NUM> to move continuously between a closed position and an open position and support the frame <NUM> at a continuous range of angles relative to a surface on which the electronic device <NUM> rests.

In conventional electronic devices with hinged support arms, the amount of force required to move the support arm <NUM> may be substantially constant throughout the range of movement. However, the amount of torque from the hinge <NUM> needed to support the electronic device <NUM> when the support arm <NUM> is positioned at a smaller angle (i.e., the hinge <NUM> is closer to the closed position and the electronic device <NUM> is nearly upright) may be less than the amount of torque needed to support the electronic device <NUM> when the support arm <NUM> is positioned at a larger angle (i.e., the hinge <NUM> is closer to the open position and the electronic device <NUM> is nearly flat). Implementations of a hinge according to present disclosure may vary the torque of the hinge relative to the position of the hinge. In other implementations, a hinge may produce a constant or near constant torque throughout the range of motion of the hinge.

<FIG> illustrate the range of movement of the implementation of a hinge <NUM> of <FIG> is a side view of the electronic device <NUM> with the hinge <NUM> in a closed position. In the closed position, the hinge <NUM> allows the support arm <NUM> to lie parallel and/or flush with the frame <NUM>. The hinge <NUM> may be continuously movable between the closed position illustrated in <FIG> and the open position illustrated in <FIG> is a side view of the implementation of an electronic device <NUM> of <FIG> with a support arm <NUM> and hinge <NUM> in an open position.

An angle <NUM> of the hinge <NUM> (e.g., the angle between the frame <NUM> and the support arm <NUM>) in the open position may be at least <NUM> degrees. The hinge <NUM> may be selectively positioned at any angle <NUM> between <NUM> degrees and <NUM> degrees and the hinge <NUM> may resist movement from that position. The hinge <NUM> may be rotatable about a lateral axis <NUM> of the hinge <NUM>. In some implementations, the lateral axis <NUM> may be a physical axle (e.g., rod, pin, post) about which the hinge <NUM> rotates. In other implementations, the lateral axis <NUM> may be a virtual axle about which a plurality of telescoping components may move.

A lateral axis <NUM> with a virtual axle may allow for a smaller vertical height of the hinge <NUM> in a closed position. For example, a vertical height of the hinge <NUM> may be in a range having an upper value, a lower value, or upper and lower values including <NUM> millimeters (mm), <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or any values therebetween. In some examples, the vertical height in the closed position may be less than <NUM>. In other examples, the vertical height in the closed position may be less than <NUM>. In yet other examples, the vertical height in the closed position may be less than <NUM>.

<FIG> and <FIG> illustrate an implementation of a hinge <NUM> with telescoping components and a progressive resistance as the hinge <NUM> moves between a closed position to an open position. <FIG> is a side cross-sectional view of an implementation of a hinge <NUM>, according to the present disclosure. The hinge <NUM> connects a frame <NUM> with an arm <NUM>. In some implementations, the frame <NUM> may be the frame of an electronic device, such as the frame <NUM> of the electronic device <NUM> of <FIG>. In other implementations, the frame <NUM> may be affixed to the frame of an electronic device. In some implementations, the arm <NUM> may be the support arm of an electronic device, such as the support arm <NUM> of the electronic device of <FIG>. In other implementations, the arm <NUM> may be affixed to the support arm of an electronic device. In at least one implementation, the hinge <NUM> may be inverted and the frame <NUM> may be connected to a support arm of an electronic device and the arm <NUM> may be connected to a frame of an electronic device.

The arm <NUM> may rotate relative to the frame <NUM> about a lateral axis <NUM>. To provide resistance to the movement of the arm <NUM>, the hinge <NUM> includes a torque element <NUM> displaced in a longitudinal direction from the lateral axis <NUM> and connected to the arm <NUM> with a link <NUM>. The torque element <NUM> includes a first portion <NUM> that rotates relative to a second portion <NUM> about a longitudinal axis <NUM>. The torque element <NUM> may have a predetermined amount of friction between the first portion <NUM> and second portion <NUM>, such that the torque element <NUM> resists rotation of the first portion <NUM> relative to the second portion <NUM>. In at least one example, the second portion <NUM> may be fixed relative to part of the link <NUM>.

The frame <NUM> includes a shaft <NUM> and/or has a shaft <NUM> connected thereto. The shaft <NUM> may at least partially limit the movement of the torque element <NUM> relative to the frame <NUM> and/or arm <NUM>. For example, the shaft <NUM> may limit and/or prevent the movement of the torque element <NUM> in the lateral direction and/or vertical direction and may allow movement of the torque element <NUM> in the longitudinal direction and/or along the longitudinal axis <NUM>. The torque element <NUM> may be positioned in contact with the shaft <NUM> and configured to interlock with at least a portion of the shaft <NUM>. The torque element <NUM> is positioned around a portion of the shaft <NUM> and a part of the torque element <NUM> may interlock with a recess <NUM> in the shaft <NUM>.

In some implementations, one or more bearings <NUM> may provide an interlock between the recess <NUM> in the shaft <NUM> and the first portion <NUM> of the torque element <NUM>. In other implementations, the first portion <NUM> may include one or more protrusions that protrude into and interlock with the recess <NUM>. In yet other implementations, the shaft <NUM> may include one or more protrusions that protrude into and interlock with a recess in the first portion <NUM> of the torque element <NUM>.

The recess <NUM> may spiral around the shaft <NUM> in the longitudinal direction. The mechanical interlock of the torque element <NUM> and the shaft <NUM> may, thereby, require the rotation of the torque element <NUM> about the longitudinal axis <NUM> during linear translation of the torque element <NUM> relative to the shaft <NUM>. In another example, the friction of the torque element <NUM> resisting a rotation of the torque element <NUM> may, thereby, cause the torque element <NUM> to resist the linear translation of the torque element <NUM> in the shaft <NUM>. Additionally, a rotation of the arm <NUM> about the lateral axis <NUM> may move the link <NUM>, which may translate the torque element <NUM>. The friction of the rotation of the torque element <NUM> as the torque element <NUM> translates along the shaft <NUM>, may resist the translation of the link <NUM> and, therefore, the rotation of the arm <NUM> about the lateral axis <NUM>.

The conversion of the rotational movement of the arm <NUM> about the lateral axis <NUM> to a substantially linear movement of the torque element <NUM> along the shaft <NUM>, and the subsequent conversion of the linear movement of the torque element <NUM> to rotational movement of the first portion <NUM> relative to the second portion <NUM> may allow for an increased rotational rate of the torque element <NUM> relative to the arm <NUM>. For example, the present example converts <NUM> degrees of rotation of the arm <NUM> about the lateral axis <NUM> to approximately <NUM> degrees of rotation of the torque element <NUM> about the longitudinal axis <NUM>, resulting in a gearing ratio (rotation of the torque element <NUM> about the longitudinal axis <NUM> to rotation of the arm <NUM> about the lateral axis <NUM>) of about <NUM>. The gearing ratio may be in a range having an upper value, a lower value, or upper and lower values including any of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or any values therebetween. For example, the gearing ratio may be greater than <NUM>. In other examples, the gearing ratio may be less than <NUM>. In yet other examples, the gearing ratio may be between <NUM> and <NUM>. In further examples, the gearing ratio may be between <NUM> and <NUM>. In yet further examples, the gearing ratio may be between <NUM> and <NUM>.

In other implementations, the conversion of the rotational movement of the arm <NUM> about the lateral axis <NUM> to a substantially linear movement of the torque element <NUM> along the shaft <NUM> may allow for a progressive change in resistance. An initial rotational movement of the arm <NUM> about the lateral axis <NUM> may displace a portion of the link <NUM> in a substantially perpendicular direction relative to the longitudinal axis <NUM>. The perpendicular movement of the link <NUM> relative to the longitudinal axis <NUM> may produce little or no linear translation of the torque element <NUM>. For example, the substantially perpendicular movement of the link <NUM> relative to the longitudinal axis <NUM> may produce less than <NUM> of linear translation of the torque element <NUM>. With little linear translation of the torque element <NUM> relative to the shaft <NUM>, the torque element <NUM> may provide little to no resistance to the movement of the arm <NUM> at the closed position. The camming action of the arm <NUM> and link <NUM> described herein may allow the arm <NUM> to rotate about the lateral axis <NUM> up to <NUM> degree, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, or <NUM> degrees with less than <NUM> of linear translation of the torque element <NUM> and/or without resistance from the torque element <NUM>.

After the initial region of perpendicular movement, the angle of the link <NUM> relative to the longitudinal axis <NUM> may increase as the rotation of the arm <NUM> about the lateral axis <NUM> increases. For example, the implementation of a hinge <NUM> is shown in an open position in <FIG>.

As shown in <FIG>, the link <NUM> is rotatably coupled to the arm <NUM> about a connection point <NUM>. An angle between the link <NUM> and the longitudinal axis <NUM> of the shaft <NUM> may increase as the arm <NUM> moves in a first rotational direction <NUM> about the lateral axis <NUM> and toward the open position. The force applied to the torque element <NUM> may, therefore, change orientation relative to the longitudinal axis <NUM>. The total force applied by the link <NUM> may increase to apply a longitudinal component <NUM> with the same magnitude.

<FIG> is a graph of an example torque curve <NUM> of the implementation of a hinge of <FIG> and <FIG> normalized to the maximum torque. The torque curve <NUM> reflects the change in angle of the link as the connection point of the link and arm is pulled in an arcuate path by the arm. The torque curve <NUM> may increase from the closed position (at or near <NUM> degrees) to an intermediate point <NUM>. The intermediate point <NUM> may be the point in the rotation of the arm where the link is oriented at a maximum angle relative to the longitudinal axis, and the torque curve <NUM> is substantially flat thereafter to the open position (at or near <NUM> degrees).

The torque curve <NUM> between the intermediate point <NUM> and the open position may be substantially flat. For example, the torque curve <NUM> may vary by less than <NUM>% between the between the intermediate point <NUM> and the open position. In other examples, the torque curve <NUM> may vary by less than <NUM>% between the between the intermediate point <NUM> and the open position. In yet other examples, the torque curve <NUM> may vary by less than <NUM>% between the between the intermediate point <NUM> and the open position. In further examples, the torque curve <NUM> may vary by less than <NUM>% between the between the intermediate point <NUM> and the open position.

In some implementations, the hinge may do less work between the closed position and the intermediate point <NUM> than between the intermediate point <NUM> and the open position. For example, the torque may increase from the closed position to the intermediate point <NUM>, and the torque may be substantially constant from the intermediate point <NUM> to the open position. Movement from the intermediate point <NUM> to the open position may, therefore, require more energy input from a user to move the arm than movement from the closed position to the intermediate point <NUM>. The intermediate point <NUM> (i.e., the point after which the torque is substantially constant) may be at <NUM> degrees from the closed position. In another example, the intermediate point <NUM> may be at <NUM> degrees from the closed position. In yet other examples, the intermediate point <NUM> may be between <NUM> degrees and <NUM> degrees from the closed position. In at least one example, the intermediate point <NUM> may be a position greater than <NUM> degree from the closed position.

The resistance of a hinge may be adjusted by changing the friction of the torque element and the shaft. For example, a torque element with increased resistance per degree of rotation about the rotational axis of the torque element will increase the work done as the hinge moves. For example, a hinge may produce similar resistance with a torque element that generates half the friction if the gearing ratio is doubled. In another example, a hinge according to the present disclosure may alter the resistance of the torque element depending on the position of the hinge at or between the closed position and open position.

In addition to the angle of the link to the longitudinal axis, additional elements of a hinge may be used to alter the resistance of the hinge at different longitudinal positions. For example, <FIG> and <FIG> illustrate another implementation of a hinge <NUM> according to the present disclosure. <FIG> is a bottom perspective view of an implementation of a hinge <NUM> in which the resistance of the hinge <NUM> includes a friction between a first portion <NUM> of the torque element <NUM> and the shaft <NUM>.

The shaft <NUM> has one or more surfaces <NUM>-<NUM>, <NUM>-<NUM> with one or more coefficients of friction with the first portion <NUM> of the torque element <NUM>. For example, the shaft <NUM> may have a first surface <NUM>-<NUM> in a first longitudinal portion of the shaft <NUM> and a second surface <NUM>-<NUM> in a second longitudinal portion of the shaft <NUM>. In some implementations, the division between the first surface <NUM>-<NUM> and the second surface <NUM>-<NUM> may correspond to a change in resistance. For example, the first surface <NUM>-<NUM> may have a lower coefficient of friction with the first portion <NUM> of the torque element <NUM> than the second surface <NUM>-<NUM>. In other implementations, the division between the first surface <NUM>-<NUM> and the second surface <NUM>-<NUM> may correspond to the intermediate point (such as the intermediate point <NUM> described in relation to <FIG>) of the arm <NUM>.

<FIG> shows the torque element <NUM> in the first longitudinal portion of the shaft <NUM> with the first portion <NUM> in contact with the first surface <NUM>-<NUM>. In some implementations, a source of resistance of the hinge <NUM> may be related to the friction between the first portion <NUM> and the shaft <NUM>. In such implementations, the second portion <NUM> of the torque element <NUM> may surround less than a full circumference of the first portion <NUM>. For example, the second portion <NUM> may have one or more openings or gaps such that the second portion <NUM> contacts only <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or less than <NUM>% of the circumference of the first portion <NUM>. There may be less friction between the first portion <NUM> and second portion <NUM> when compared to a first portion <NUM> that is continuous about the full circumference, but the height of the first portion in a vertical direction may be decreased, reducing an overall height of the hinge <NUM>.

<FIG> illustrates the torque element <NUM> moved in a longitudinal direction along the shaft <NUM> as the arm <NUM> moves toward the open position. The torque element <NUM> may move from the first longitudinal portion of the shaft <NUM> to the second longitudinal portion and may contact the second surface <NUM>-<NUM>. The second surface <NUM>-<NUM> may have a second coefficient of friction, changing the friction between the shaft <NUM> and the first portion <NUM> of the torque element <NUM>. In some implementations, a second surface <NUM>-<NUM> with a greater coefficient of friction may increase the resistance of the hinge <NUM> as the arm <NUM> approaches the open position.

The resistance of the hinge may further be altered independently of the coefficient of friction by altering a pitch of the interlock between the torque element and the shaft. For example, <FIG> is a side view of another implementation of a shaft <NUM>. The shaft <NUM> may have a recess with a first portion of the recess <NUM>-<NUM> with a first pitch and a second portion of the recess <NUM>-<NUM> with a second pitch. In some implementations, the first pitch may be less than the second pitch. In other implementations, the first pitch may be greater than the second pitch. For example, a shaft <NUM> with a different first pitch and second pitch may cause relative rotation of the torque element and the shaft <NUM> at different rates depending upon the longitudinal position of the torque element relative to the shaft <NUM>.

In some implementations, increasing the rotational rate of the torque element relative to the longitudinal distance traveled may increase the work done given a constant friction of the torque element. In other implementations, decreasing the rotational rate of the torque element relative to the longitudinal distance traveled may decrease the work done given a constant friction of the torque element. In yet other implementations, the pitch and the friction may vary with the relative longitudinal position of the torque element and shaft.

<FIG> is a flowchart of an implementation of a method <NUM> of applying torque to a hinge, such as to support an electronic device. The method <NUM> may include rotating an arm about a first lateral axis at <NUM> and moving a link connected to the arm at <NUM>. The link may be connected to a torque element and a movement of the link may translate the torque element relative to a shaft in a longitudinal direction at <NUM>. The torque element may be in contact with the shaft and, the translation of the torque element along the shaft may rotate the torque element about a longitudinal axis at <NUM>.

The shaft and the torque element may interact through interlocking features, such as a recess, a protrusion, a bearing, or other surface features. For example, an interlocking recess and bearing may limit and/or prevent the longitudinal movement of the torque element relative to the shaft without rotation of the torque element. In other examples, the shaft and the torque element may interact through friction. For example, a frictional force between the track and the torque element may limit and/or prevent the longitudinal movement of the torque element relative to the track without rotation of the torque element.

The rate of rotation of a portion of the torque element about the shaft may vary. For example, the shaft may have a first pitch and a second pitch that are different. The first pitch may rotate the portion of the torque element at a first rate and the second pitch may rotate the portion of the torque element at a second rate. In other examples, the pitch may be continuously variable such that the rate of rotation continuous changes along the longitudinal direction of the shaft. In another example, the pitch may be substantially constant along the longitudinal direction of the shaft.

The method <NUM> may further include resisting the rotation of the torque element about the longitudinal axis at <NUM>. In some implementations, a first portion of the torque element may resist rotation relative to a second portion of the torque element. In other implementations, a portion of the torque element may be in contact with a portion of the shaft and may resist the rotation of the torque element relative to the track. In at least one implementation, a hinge according to the present disclosure may allow for a greater resistance and/or progressive resistance of the movement of an arm about a lateral axis.

One or more specific implementations of the present disclosure are described herein. These described implementations are examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these implementations, not all features of an actual implementation may be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions will be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another.

The articles "a," "an," and "the" are intended to mean that there are one or more of the elements in the preceding descriptions. Additionally, it should be understood that references to "one implementation" or "an implementation" of the present disclosure are not intended to be interpreted as excluding the existence of additional implementations that also incorporate the recited features. For example, any element described in relation to an implementation herein may be combinable with any element of any other implementation described herein. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are "about" or "approximately" the stated value, as would be appreciated by one of ordinary skill in the art encompassed by implementations of the present disclosure. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result. The stated values include at least the variation to be expected in a suitable manufacturing or production process, and may include values that are within <NUM>%, within <NUM>%, within <NUM>%, or within <NUM>% of a stated value.

A person having ordinary skill in the art should realize in view of the present disclosure that equivalent constructions do not depart from the spirit and scope of the present disclosure. Equivalent constructions, including functional "means-plus-function" clauses are intended to cover the structures described herein as performing the recited function, including both structural equivalents that operate in the same manner, and equivalent structures that provide the same function. It is the express intention of the applicant not to invoke means-plus-function or other functional claiming for any claim except for those in which the words 'means for' appear together with an associated function. Each addition, deletion, and modification to the implementations that falls within the meaning and scope of the claims is to be embraced by the claims.

The terms "approximately," "about," and "substantially" as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms "approximately," "about," and "substantially" may refer to an amount that is within less than <NUM>% of, within less than <NUM>% of, within less than <NUM>% of, and within less than <NUM>% of a stated amount. Further, it should be understood that any directions or reference frames in the preceding description are merely relative directions or movements. For example, any references to "up" and "down" or "above" or "below" are merely descriptive of the relative position or movement of the related elements.

Claim 1:
A device (<NUM>) for controlling movement of a support, the device (<NUM>) comprising:
a frame (<NUM>);
an arm (<NUM>) rotatably connected to the frame (<NUM>) about a lateral axis (<NUM>);
a torque element (<NUM>) configured to be displaced from the lateral axis (<NUM>) in a longitudinal direction perpendicular to the lateral axis (<NUM>), part of the torque element (<NUM>) being rotatable about a longitudinal axis (<NUM>); and
a link (<NUM>) connected to the arm (<NUM>) and the torque element (<NUM>) such that rotation of the arm (<NUM>) about the lateral axis (<NUM>) translates the torque element (<NUM>) in the longitudinal direction, wherein
the frame comprises a shaft connected thereto and
characterised in that
the torque element being positioned
around at least a portion of the shaft such that longitudinal displacement of the torque element relative to the shaft rotates a portion of the torque element.