Patent Description:
The following documents may provide technical background to the present disclosure: <CIT>; <CIT>; <CIT>; and <CIT>.

Examples are disclosed that relate to hinge assemblies for rotatably coupling a first substrate of a computing device to a second substrate of the computing device. As defined in appended claim <NUM>, a hinge assembly comprises a first hinge bracket affixed to the first substrate and comprising a first drive gear and first drive gear shaft. A second hinge bracket is affixed to the second substrate and comprises a second drive gear and second drive gear shaft. A first idler gear engages the first drive gear and a second idler gear, with the second idler gear engaging the second drive gear. The first idler gear comprises a first idler gear shaft and the second idler gear comprises a second idler gear shaft.

A first friction band comprises a first arcuate contacting surface, an opposing second arcuate contacting surface, and a first biasing portion between the first arcuate contacting surface and the second arcuate contacting surface. The first biasing portion is biased in a first direction to press the first arcuate contacting surface against a first portion of the first drive gear shaft and the second arcuate contacting surface against a third portion of the second drive gear shaft. A second friction band, separate to the first friction band, comprises a third arcuate contacting surface, an opposing fourth arcuate contacting surface, and a second biasing portion between the third arcuate contacting surface and the fourth arcuate contacting surface. The second biasing portion is biased in a second direction opposite to the first direction to press the third arcuate contacting surface against a second portion of the first drive gear shaft and the fourth arcuate contacting surface against a fourth portion of the second drive gear shaft. Advantageously and as described further below, in this configuration the first friction band and the second friction band are moveable independently of one another to balance torque applied to the first drive gear shaft and the second drive gear shaft.

In another embodiment, a computing device comprises a first display substrate and a second display substrate rotatably coupled to the first display substrate via two hinge assemblies as described above. Each of the hinge assemblies comprises a first hinge bracket affixed to the first substrate and comprising a first drive gear and first drive gear shaft. A second hinge bracket is affixed to the second substrate and comprises a second drive gear and second drive gear shaft. A first idler gear engages the first drive gear and a second idler gear, with the second idler gear engaging the second drive gear. The first idler gear comprises a first idler gear shaft and the second idler gear comprises a second idler gear shaft.

A first friction band comprises a first arcuate contacting surface, an opposing second arcuate contacting surface, and a first biasing portion between the first arcuate contacting surface and the second arcuate contacting surface. The first biasing portion is biased in a first direction to press the first arcuate contacting surface against a first portion of the first drive gear shaft and the second arcuate contacting surface against a third portion of the second drive gear shaft. A second friction band comprises a third arcuate contacting surface, an opposing fourth arcuate contacting surface, and a second biasing portion between the third arcuate contacting surface and the fourth arcuate contacting surface. The second biasing portion is biased in a second direction opposite to the first direction to press the third arcuate contacting surface against a second portion of the first drive gear shaft and the fourth arcuate contacting surface against a fourth portion of the second drive gear shaft.

The claimed invention also provides a method of rotatably coupling a first display substrate of a computing device to a second display substrate via at least one hinge assembly. The method comprises engaging a first idler gear with a second idler gear and a first drive gear of a first hinge bracket, wherein the first idler gear comprises a first idler gear shaft and the second idler gear comprises a second idler gear shaft. The second idler gear is also engaged with a second drive gear of a second hinge bracket. A first biasing portion of a first friction band is biased in a first direction to press a first arcuate contacting surface of the first friction band against a first portion of a first drive gear shaft of the first hinge bracket, and press a second arcuate contacting surface of the first friction band opposite to the first arcuate contacting surface against a third portion of a second drive gear shaft of the second hinge bracket.

A second biasing portion of a second friction band is biased in a second direction opposite to the first direction to press a third arcuate contacting surface of the second friction band against a second portion of the first drive gear shaft, and press a fourth arcuate contacting surface of the second friction band opposite to the third arcuate contacting surface against a fourth portion of the second drive gear shaft, wherein the second friction band is separate to the first friction band. The first hinge bracket is then affixed to the first display substrate, and the second hinge bracket is affixed to the second display substrate.

As noted above, some foldable computing devices utilize two displays with hinges that allow the displays to fold relative to one another. Some hinge mechanisms generate torque on shafts coupled to the displays to enable the displays to maintain particular orientations. However, when such torque is applied unevenly to the shafts, the displays can move at different rates of rotation and provide an undesirable user experience. Such mismatched torque amounts also cause uneven wear on gear surfaces of hinge gear trains, thereby increasing gear backlash over time.

Accordingly, the present disclosure describes computing devices, hinge assemblies, and related methods that address one or more of the above-described issues. As described in more detail below, hinge assemblies of the present disclosure include first and second hinge brackets affixed to corresponding substrates of a foldable computing device. Each hinge bracket includes a drive gear and shaft. First and second idler gears engage the drive gears. A first friction band comprises a first biasing portion that is biased in a first direction to press a first arcuate contacting surface of the first friction band against the first drive gear shaft and a second arcuate contacting surface against the second drive gear shaft. A second friction band opposite the first friction band comprises a second biasing portion that is biased in an opposing second direction to press a third arcuate contacting surface of the second friction band against the first drive gear shaft and a fourth arcuate contacting surface against the second drive gear shaft.

<FIG> show one example of a computing device <NUM> and hinge assemblies <NUM> according to examples of the present disclosure. In this example, computing device <NUM> is a foldable computing device that includes a first display substrate <NUM> rotatably coupled to a second display substrate <NUM> via hinge assemblies <NUM>. In some examples, the first display substrate <NUM> and second display substrate <NUM> are rotatable through approximately <NUM> degrees relative to one another. In other examples, the first display substrate <NUM> and second display substrate <NUM> are rotatable through less than <NUM> degrees relative to one another.

In this example, two hinge assemblies <NUM> are utilized to couple the first and second display substrates. In other examples, a single hinge assembly or three or more hinge assemblies of the present disclosure can be utilized to rotatably couple two substrates of a computing device.

With reference to <FIG>, each of the hinge assemblies <NUM> comprises a first hinge bracket <NUM> that is affixed to the first substrate <NUM>. In this example and as indicated in <FIG>, the first hinge brackets <NUM> are located within the first substrate <NUM> to be out of view of the user. The first hinge brackets <NUM> are affixed to the first substrate <NUM> using one or more fasteners, such as screws. In the present example, the first hinge bracket <NUM> includes three apertures <NUM> that each receive screws (not shown) for fastening the bracket to the first substrate <NUM>.

As shown in <FIG>, each first hinge bracket <NUM> comprises a first drive gear <NUM> and first drive gear shaft <NUM>. The first drive gear <NUM> and first drive gear shaft <NUM> are rigidly affixed to the hinge bracket, such that rotation of the first drive gear causes rotation of the bracket (and attached substrate). As described in more detail below, the first drive gear <NUM> forms one component of a synchronizing gear train that synchronizes rotation of the first substrate <NUM> and second substrate <NUM> as the two substrates are moved relative to one another utilizing hinge assemblies <NUM>.

In a similar manner, each of the hinge assemblies <NUM> comprises a second hinge bracket <NUM> that is affixed to the second substrate <NUM>. Like the first hinge brackets <NUM>, the second hinge brackets <NUM> are located within the second substrate <NUM> out of view of the user. The second hinge brackets <NUM> are affixed to the second substrate <NUM> using one or more fasteners, such as screws. In the present example, the second hinge bracket <NUM> includes three apertures <NUM> that each receive screws (not shown) for fastening the bracket to the second substrate <NUM>.

Like the first hinge brackets <NUM>, each of the second hinge brackets <NUM> comprises a second drive gear <NUM> and second drive gear shaft <NUM> that are rigidly affixed to the hinge brackets. As noted above, the second drive gear <NUM> forms one component of the synchronizing gear train that synchronizes rotation of the first substrate <NUM> and second substrate <NUM> as the two substrates are moved relative to one another utilizing hinge assemblies <NUM>. More particularly and with reference to <FIG> and <FIG>, a first idler gear <NUM> engages the first drive gear <NUM> and a second idler gear <NUM>. The second idler gear <NUM> also engages the second drive gear <NUM>. In this manner, when one of the first or second substrates is rotated about its corresponding drive gear, this gear train causes the other substrate to rotate about its drive gear in a corresponding manner.

With reference now to <FIG> and <FIG>, and in one potential advantage of the present disclosure, each hinge assembly <NUM> utilizes a first friction band <NUM> that presses in a first direction against the first and second drive gear shafts <NUM>, <NUM>, and an opposing, separate second friction band <NUM> that presses against opposite sides of the first and second drive gear shafts <NUM>, <NUM> in the opposite direction to balance torque applied to the two shafts. Advantageously and as described in more detail below, because these two friction bands are moveable independently of one another, the torque loads on each drive shaft are actively balanced to reduce torque differences between the two shafts.

In the present example of <FIG> and <FIG>, each hinge assembly <NUM> includes a first friction band <NUM> comprising a first arcuate contacting surface <NUM>, an opposing second arcuate contacting surface <NUM>, and a first biasing portion <NUM> between the first arcuate contacting surface and the second arcuate contacting surface. In this example the first biasing portion <NUM> comprises a first arcuate biasing surface <NUM> about which the first friction band is pivotable. As described further below, the first arcuate biasing surface <NUM> is biased in a first direction <NUM> toward the two drive gear shafts to press the first arcuate contacting surface <NUM> against a first portion of the first drive gear shaft <NUM> and press the second arcuate contacting surface <NUM> against a third portion of the second drive gear shaft <NUM>. Advantageously, the curvature of the first arcuate biasing surface <NUM> (and second arcuate biasing surface <NUM> described below) enables the biasing portion to self-adjust and compensate for component changes over time, such as wearing of the first and/or second arcuate contacting surfaces <NUM>, <NUM>, by pivoting against a first inner surface <NUM> of the enclosure <NUM> described further below. In this manner, the frictional forces applied by the first and second arcuate contacting surfaces <NUM>, <NUM> to the first portion of the first drive gear shaft <NUM> the third portion of the second drive gear shaft <NUM>, respectively, are correspondingly adjusted and more evenly distributed. Further, the curvatures of the first and second arcuate contacting surfaces <NUM>, <NUM> substantially match the curvatures of the first drive gear shaft <NUM> and second drive gear shaft, respectively, to advantageously apply frictional force to the shafts across the entire surface areas of the contacting surfaces.

In a similar manner, each hinge assembly <NUM> includes an opposing second friction band <NUM> comprising a third arcuate contacting surface <NUM>, an opposing fourth arcuate contacting surface <NUM>, and a second biasing portion <NUM> between the third arcuate contacting surface and the fourth arcuate contacting surface. As with the first friction band <NUM>, in this example the second biasing portion <NUM> comprises a second arcuate biasing surface <NUM> about which the second friction band <NUM> is pivotable. The second arcuate biasing surface <NUM> is biased in a second direction <NUM> opposite to the first direction <NUM> to press the third arcuate contacting surface <NUM> against an opposing second portion of the first drive gear shaft <NUM> and press the fourth arcuate contacting surface <NUM> against an opposing fourth portion of the second drive gear shaft <NUM>.

In this example, to provide the biasing force that presses the arcuate contacting surfaces of the first friction band <NUM> and second friction band <NUM> against the first drive gear shaft <NUM> and second drive gear shaft <NUM>, respectively, the first friction band and second friction band are inserted into an enclosure <NUM>. As best seen in <FIG>, which omits the first disc stop <NUM>, end cap <NUM>, and cable bracket <NUM> for clarity, when the first friction band <NUM> and second friction band <NUM> are inserted, the enclosure <NUM> provides an interference fit in which a first inner surface <NUM> of the enclosure compresses the first arcuate biasing surface <NUM> of the first central portion <NUM> of the first friction band in the first direction <NUM>, which in turn presses the first arcuate contacting surface <NUM> against the first drive gear shaft <NUM> and the second arcuate contacting surface <NUM> against the second drive gear shaft <NUM>.

Similarly, the enclosure <NUM> provides an interference fit with the second friction band <NUM> in which a second inner surface <NUM> of the enclosure compresses the second arcuate biasing surface <NUM> of the second central portion <NUM> of the second friction band in the second direction <NUM> opposite to the first direction <NUM>, which in turn presses the third arcuate contacting surface <NUM> against the opposite side of the first drive gear shaft <NUM> and the fourth arcuate contacting surface <NUM> against the opposite side of the second drive gear shaft <NUM>. Additionally, and in another potential advantage of this configuration, in addition to providing an interference fit, the enclosure <NUM> operates to protect the friction bands and other components from external contact and potential damage.

In the present example, the first direction <NUM> and the second direction <NUM> are orthogonal to axes <NUM>, <NUM> of the first drive gear shaft <NUM> and the second drive gear shaft <NUM>, respectively. In this manner, the contact pressure between the arcuate contacting surfaces of the first friction band <NUM> and second friction band <NUM> and the surfaces of the first drive gear shaft <NUM> and second drive gear shaft <NUM> is substantially evenly distributed across the surfaces. Accordingly, by providing a more uniform distribution of force across the two drive gear shafts and the arcuate contacting surfaces, over time these surfaces may wear at more consistent rates, thereby extending the useful life of these components and providing a more uniform user experience.

As shown in <FIG>, with the first friction band <NUM> and second friction band <NUM> inserted and press-fit into the enclosure <NUM>, a gap <NUM> is maintained between these two structures. In this manner, the compression of the first drive gear shaft <NUM> between the first arcuate contacting surface <NUM> and the third arcuate contacting surface <NUM> and the compression of the second drive gear shaft <NUM> between the second arcuate contacting surface <NUM> and the fourth arcuate contacting surface <NUM> creates frictional resistance to rotation of the gear shafts that enables the attached displays to maintain particular orientations relative to one another. Additionally, and in another potential advantage of the present disclosure, by utilizing two independent and separate friction bands, the two friction bands can pivot independently of one another, and accordingly are independently self-adjustable over the life of the mechanism to compensate for different component wear rates, for example. Further, by compressing the two friction bands together at centrally-located pivot points on their respective arcuate biasing surfaces <NUM> and <NUM> that are positioned between the axes <NUM>, <NUM> of the two drive gear shafts <NUM>, <NUM>, respectively, each of the friction bands can independently pivot and balance out the forces applied to the two drive gear shafts.

For example, if the two drive gear shafts have slightly different diameters and/or the inside diameters of the opposing contacting surfaces of the friction bands are different, the present configuration advantageously minimizes or substantially eliminates potential torque differences applied to the drive shafts by centrally pivoting the two friction bands to balance out the forces applied to the drive gear shafts.

In another potential advantage of this example, the enclosure's first inner surface <NUM> and second inner surface <NUM> are recessed within the enclosure <NUM> such that the first and second friction bands <NUM>, <NUM> are recessed within the enclosure when installed. This is illustrated in <FIG> in which the first and second friction bands <NUM>, <NUM> are located within the enclosure <NUM>. Advantageously, this configuration protects the first and second friction bands <NUM>, <NUM> from outside contact, and similarly encloses and protects the first drive gear <NUM>, second drive gear, first idler gear <NUM>, and second idler gear <NUM> (see also <FIG>).

As shown in <FIG> and <FIG>, a cable bracket <NUM> is also installed on the end of the enclosure <NUM> to capture and route one or more cables. With reference to <FIG> and <FIG>, a first disc stop <NUM> and second disc stop <NUM> are fitted over a first cylindrical protrusion <NUM> and second cylindrical protrusion <NUM> of the first drive gear shaft <NUM> and second drive gear shaft <NUM>, respectively. In <FIG>, <FIG> the first disc stop <NUM> is not shown for descriptive purposes. As shown in <FIG> an end cap <NUM> is inserted into the enclosure <NUM> to cover the first disc stop <NUM> and second disc stop <NUM>.

With reference to <FIG>, in this example both friction bands include holes in which the two idler gear shafts are rotatably received. More particularly, the first friction band <NUM> includes a first idler hole <NUM> that rotatably receives the first idler gear shaft <NUM> of the first idler gear <NUM>. Similarly, the second friction band <NUM> includes a second idler hole <NUM> that rotatably receives the second idler gear shaft <NUM> of the second idler gear <NUM>. As shown in <FIG> and with reference also to <FIG>, the first idler hole <NUM> and second idler hole <NUM> are offset in the y-axis direction to align the corresponding idler gears <NUM>, <NUM> in the gear train with the first and second drive gears <NUM>, <NUM>.

With reference now to <FIG>, in other example configurations two friction bands are configured to receive an idler gear retention component that rotatably receives the first idler gear shaft <NUM> and the second idler gear shaft <NUM>. As described in more detail below, with these configurations during assembly the idler gear retention component can be rotated to remove backlash between the idler gears and the drive gears, at which point the idler gear retention component is affixed to either the first and second friction bands or to the enclosure. In this manner, by affixing the idler gear retention component after backlash between the idler gears and drive gears has been removed, the hinge assembly can be operated to smoothly rotate the two displays without gear backlash.

<FIG> illustrates two examples of idler gear retention components that may be utilized with an alternative first friction band <NUM> and alternative second friction band <NUM>. As described further below, in each example the idler gear retention component is received in an idler gear retention component aperture <NUM> formed by the alternative first friction band <NUM> and alternative second friction band <NUM>. More particularly, the alternative first friction band <NUM> comprises a first arcuate feature <NUM> in a first arcuate biasing portion <NUM> and the second alternative friction band <NUM> comprises a second arcuate feature <NUM> in a second arcuate biasing portion <NUM>, with the first arcuate feature and the second arcuate feature cooperating to form the idler gear retention component aperture <NUM>. Advantageously and as described in more detail below, these arcuate features forming the idler gear retention component aperture <NUM> enable the idler gear retention component to be received and rotated to remove backlash between the idler gears and the drive gears.

The arcuate contacting surfaces of the alternative first and second friction bands <NUM>, <NUM> that contact the first and second drive gear shafts <NUM>, <NUM> have the same configuration as the arcuate contacting surfaces <NUM>, <NUM>, <NUM>, and <NUM> of the first and second friction bands <NUM>, <NUM> described above. Additionally and like the first and second friction bands <NUM>, <NUM>, the alternative first and second friction bands <NUM>, <NUM> include first and second arcuate biasing portions <NUM>, <NUM> that contact the corresponding first inner surface <NUM> and second inner surface <NUM>, respectively, of the enclosure <NUM> to create an interference that presses the arcuate contacting surfaces against the first drive gear shaft <NUM> and the second drive gear shaft <NUM> as described above.

With reference to <FIG> and <FIG> and described further below, in one configuration an idler gear retention component <NUM> is received in the idler gear retention component aperture <NUM> formed by the alternative first friction band <NUM> and alternative second friction band <NUM>. In this example the idler gear retention component <NUM> comprises a cylindrical structure including a first bore <NUM> that rotatably receives the first idler gear shaft <NUM> and a second bore <NUM> that rotatably receives the second idler gear shaft <NUM>.

As noted above, and in one potential advantage of this configuration, during assembly the idler gear retention component <NUM> can be rotated to remove backlash between the idler gears and the drive gears. In one example, the idler gear retention component <NUM> is inserted into the idler gear retention component aperture <NUM>. The first idler gear shaft <NUM> is inserted into the first bore <NUM> and the second idler gear shaft <NUM> is inserted into the second bore <NUM>. With the idler gear retention component <NUM> having received the first and second idler gear shafts <NUM>, <NUM> and being inserted into the idler gear retention component aperture <NUM>, in some examples a tooth of an idler gear may not be contacting the face of a corresponding tooth of the adjacent drive gear. For example, <FIG> illustrates an example in which a first idler tooth <NUM> of the first idler gear <NUM> in <FIG> is not contacting the face of a drive tooth of the corresponding drive gear <NUM>. If the first idler gear <NUM> and first drive gear <NUM> were left in this positioning, this backlash or slop between the teeth of the first idler gear and first drive gear can result in a less desirable user experience, such as a loose or discontinuous feeling when the display substrates are rotated.

To address this potential issue and with reference to the example of <FIG>, <FIG>, when the idler gear retention component <NUM> is located in the idler gear retention component aperture <NUM>, the idler gear retention component is rotated to engage the face <NUM> of the first idler tooth <NUM> with the face <NUM> of the first drive tooth <NUM>. In the present example and as shown in <FIG>, the idler gear retention component <NUM> is rotated in a counter-clockwise direction. In other examples the idler gear retention component <NUM> can be rotated in a clockwise direction to achieve similar results. Additionally, and with reference to <FIG>, it will be appreciated that such rotation of the idler gear retention component <NUM> also causes an idler tooth <NUM> of the second idler gear <NUM> to engage with a drive tooth <NUM> of the second drive gear <NUM> in a similar manner.

After rotating the idler gear retention component <NUM> as described above, the idler gear retention component is then affixed in this adjusted position. In this manner, and in another potential advantage of the present disclosure, this configuration removes any backlash between the idler gears and the drive gears at the manufacturing stage of hinge assembly <NUM>.

In some examples, after rotation the idler gear retention component <NUM> is affixed to the alternative first friction band <NUM> and to the alternative second friction band <NUM>. In one example and with reference to <FIG>, the idler gear retention component <NUM> is welded at welds <NUM> to the alternative first friction band <NUM> and to the alternative second friction band <NUM>. In these examples, welding the idler gear retention component <NUM> to the alternative first friction band <NUM> and the alternative second friction band <NUM> provides a cost-effective, simple, and quick fastening method for securing the idler gear retention component in position.

With reference now to <FIG> and <FIG>, in another example implementation an alternative idler gear retention component <NUM> includes additional features that provide a different manner of affixing the idler gear retention component after rotation. As illustrated in these figures, and like the idler gear retention component <NUM> described above, the alternative idler gear retention component <NUM> also comprises a cylindrical structure including a first bore <NUM> that rotatably receives the first idler gear shaft <NUM> and a second bore <NUM> that rotatably receives the second idler gear shaft <NUM>. In this example, the alternative idler gear retention component also includes a first tab <NUM> extending from a distal end of the component and an opposing second tab <NUM> also extending from the distal end.

After the alternative idler gear retention component <NUM> is inserted into the idler gear retention component aperture <NUM> and rotated as described above, and with reference now to <FIG>, the first tab <NUM> and second tab <NUM> are affixed to interior surfaces <NUM> and <NUM>, respectively, of the enclosure <NUM>. In this example, the first tab <NUM> is welded to interior surface <NUM> and the second tab <NUM> is welded to interior surface <NUM> at welds <NUM>. In this manner, and in one potential advantage of this configuration, affixing the alternative idler gear retention component <NUM> to interior surfaces <NUM> and <NUM> of the enclosure <NUM> via first tab <NUM> and second tab <NUM> avoids imparting heat to the first and second alternative first friction bands <NUM>, <NUM>, thereby decreasing any risk of heat-induced structural conditioning that could impact structural strength of the alternative friction bands.

With reference now to <FIG> and <FIG>, an example method <NUM> of rotatably coupling a first display substrate of a computing device to a second display substrate will now be described. The following description of method <NUM> is provided with reference to the components described herein and shown in <FIG>. For example, the method <NUM> may be performed using the components of any of the examples of hinge assemblies <NUM> described herein.

It will be appreciated that following description of method <NUM> is provided by way of example and is not meant to be limiting. Therefore, it is to be understood that method <NUM> may include additional and/or alternative steps relative to those illustrated in <FIG>. Further, it is to be understood that the steps of method <NUM> may be performed in any suitable order. Further still, it is to be understood that one or more steps may be omitted from method <NUM> without departing from the scope of this disclosure. It will also be appreciated that method <NUM> also may be performed in other contexts using other suitable components.

With reference to <FIG>, at <NUM> the method <NUM> includes engaging a first idler gear with a second idler gear and a first drive gear of a first hinge bracket, wherein the first idler gear comprises a first idler gear shaft and the second idler gear comprises a second idler gear shaft. At <NUM> the method <NUM> includes engaging the second idler gear with a second drive gear of a second hinge bracket. At <NUM> the method <NUM> includes biasing in a first direction a first biasing portion of a first friction band to press a first arcuate contacting surface of the first friction band against a first portion of a first drive gear shaft of the first hinge bracket, and press a second arcuate contacting surface of the first friction band opposite to the first arcuate contacting surface against a third portion of a second drive gear shaft of the second hinge bracket.

At <NUM> the method <NUM> includes biasing in a second direction opposite to the first direction a second biasing portion of a second friction band to press a third arcuate contacting surface of the second friction band against a second portion of the first drive gear shaft, and press a fourth arcuate contacting surface of the second friction band opposite to the third arcuate contacting surface against a fourth portion of the second drive gear shaft. At <NUM> the method <NUM> includes affixing the first hinge bracket to the first display substrate. At <NUM> the method <NUM> includes affixing the second hinge bracket to the second display substrate.

With reference now to <FIG>, at <NUM> the method <NUM> includes, where the first friction band and the second friction band form an idler gear retention component aperture, locating an idler gear retention component within the idler gear retention component aperture. At <NUM> the method <NUM> includes inserting the first idler gear shaft into a first bore in the idler gear retention component. At <NUM> the method <NUM> includes inserting the second idler gear shaft into a second bore in the idler gear retention component. At <NUM> the method <NUM> includes rotating the idler gear retention component to engage an idler tooth of the first idler gear with a drive tooth of the first drive gear, and engage an idler tooth of the second idler gear with a drive tooth of the second drive gear. At <NUM> the method <NUM> includes affixing the idler gear retention component to either the first friction band and the second friction band, or to an enclosure in which the first friction band and the second friction band are located.

The following paragraphs provide additional support for the claims of the subject application. One aspect provides a hinge assembly for rotatably coupling a first substrate of a computing device to a second substrate of the computing device, the hinge assembly comprising: a first hinge bracket configured to be affixed to the first substrate and comprising a first drive gear and first drive gear shaft; a second hinge bracket configured to be affixed to the second substrate and comprising a second drive gear and second drive gear shaft; a first idler gear engaging the first drive gear and a second idler gear, the second idler gear engaging the second drive gear, wherein the first idler gear comprises a first idler gear shaft and the second idler gear comprises a second idler gear shaft; a first friction band comprising a first arcuate contacting surface, an opposing second arcuate contacting surface, and a first biasing portion between the first arcuate contacting surface and the second arcuate contacting surface, wherein the first biasing portion is biased in a first direction to operatively press the first arcuate contacting surface against a first portion of the first drive gear shaft and the second arcuate contacting surface against a third portion of the second drive gear shaft; and a second friction band comprising a third arcuate contacting surface, an opposing fourth arcuate contacting surface, and a second biasing portion between the third arcuate contacting surface and the fourth arcuate contacting surface, wherein the second biasing portion is biased in a second direction opposite to the first direction to operatively press the third arcuate contacting surface against a second portion of the first drive gear shaft and the fourth arcuate contacting surface against a fourth portion of the second drive gear shaft. The hinge assembly may additionally or alternatively include, wherein the first biasing portion comprises a first arcuate biasing surface about which the first friction band is pivotable, and the second biasing portion comprises a second arcuate biasing surface about which the second friction band is pivotable. The hinge assembly may additionally or alternatively include an enclosure in which the first friction band and the second friction band are located, the enclosure comprising: a first inner surface contacting the first arcuate biasing surface of the first friction band in an interference fit; and a second inner surface contacting the second arcuate biasing surface of the second friction band in an interference fit. The hinge assembly may additionally or alternatively include, wherein the first direction and the second direction are orthogonal to axes of the first drive gear shaft and the second drive gear shaft. The hinge assembly may additionally or alternatively include, wherein the first friction band further defines a first idler hole that rotatably receives the first idler gear shaft, and the second friction band further defines a second idler hole that rotatably receives the second idler gear shaft. The hinge assembly may additionally or alternatively include an idler gear retention component received in an idler gear retention component aperture formed by the first friction band and the second friction band, the idler gear retention component comprising a first bore that rotatably receives the first idler gear shaft and a second bore that rotatably receives the second idler gear shaft. The hinge assembly may additionally or alternatively include, wherein the first friction band comprises a first arcuate feature in the first biasing portion, the second friction band comprises a second arcuate feature in the second biasing portion, and the first arcuate feature and the second arcuate feature form the idler gear retention component aperture. The hinge assembly may additionally or alternatively include, wherein the idler gear retention component is affixed to the first friction band and to the second friction band. The hinge assembly may additionally or alternatively include, wherein the idler gear retention component comprises: a first tab that is affixed to an enclosure in which the first friction band and the second friction band are located; and a second tab, opposite the first tab, that is affixed to the enclosure.

Another aspect provides a computing device, comprising: a first display substrate; and a second display substrate rotatably coupled to the first display substrate via at least one hinge assembly as described in any of the configurations of hinge assemblies described herein. The computing device may additionally or alternative include, wherein the second display substrate is rotatably coupled to the first display substrate via a first and a second hinge assembly as described in any of the configurations of hinge assemblies described herein.

Another aspect provides a method of rotatably coupling a first display substrate of a computing device to a second display substrate, the method comprising: engaging a first idler gear with a second idler gear and a first drive gear of a first hinge bracket, wherein the first idler gear comprises a first idler gear shaft and the second idler gear comprises a second idler gear shaft; engaging the second idler gear with the a second drive gear of a second hinge bracket; biasing in a first direction a first biasing portion of a first friction band to press a first arcuate contacting surface of the first friction band against a first portion of a first drive gear shaft of the first hinge bracket, and press a second arcuate contacting surface of the first friction band opposite to the first arcuate contacting surface against a third portion of a second drive gear shaft of the second hinge bracket; biasing in a second direction opposite to the first direction a second biasing portion of a second friction band to press a third arcuate contacting surface of the second friction band against a second portion of the first drive gear shaft, and press a fourth arcuate contacting surface of the second friction band opposite to the third arcuate contacting surface against a fourth portion of the second drive gear shaft; affixing the first hinge bracket to the first display substrate; and affixing the second hinge bracket to the second display substrate. The method may additionally or alternatively include, wherein the first friction band and the second friction band form an idler gear retention component aperture, locating an idler gear retention component within the idler gear retention component aperture; inserting the first idler gear shaft into a first bore in the idler gear retention component; inserting the second idler gear shaft into a second bore in the idler gear retention component; rotating the idler gear retention component to engage an idler tooth of the first idler gear with a drive tooth of the first drive gear, and engage an idler tooth of the second idler gear with a drive tooth of the second drive gear; and affixing the idler gear retention component to either the first friction band and the second friction band, or to an enclosure in which the first friction band and the second friction band are located.

Claim 1:
A hinge assembly (<NUM>) for rotatably coupling a first substrate (<NUM>) of a computing device to a second substrate (<NUM>) of the computing device, the hinge assembly comprising:
a first hinge bracket (<NUM>) configured to be affixed to the first substrate (<NUM>) and comprising a first drive gear (<NUM>) and first drive gear shaft (<NUM>);
a second hinge bracket (<NUM>) configured to be affixed to the second substrate (<NUM>) and comprising a second drive gear (<NUM>) and second drive gear shaft (<NUM>);
a first idler gear (<NUM>) engaging the first drive gear (<NUM>) and a second idler gear (<NUM>), the second idler gear (<NUM>) engaging the second drive gear (<NUM>), wherein the first idler gear (<NUM>) comprises a first idler gear shaft (<NUM>) and the second idler gear (<NUM>) comprises a second idler gear shaft (<NUM>);
a first friction band (<NUM>; <NUM>) comprising a first arcuate contacting surface (<NUM>), an opposing second arcuate contacting surface (<NUM>), and a first biasing portion (<NUM>) between the first arcuate contacting surface (<NUM>) and the second arcuate contacting surface (<NUM>), wherein the first biasing portion (<NUM>) is biased in a first direction (<NUM>) to operatively press the first arcuate contacting surface (<NUM>) against a first portion of the first drive gear shaft (<NUM>) and the second arcuate contacting surface (<NUM>) against a third portion of the second drive gear shaft (<NUM>); and
a second friction band (<NUM>; <NUM>) separate to the first friction band (<NUM>; <NUM>), the second friction band (<NUM>) comprising a third arcuate contacting surface (<NUM>), an opposing fourth arcuate contacting surface (<NUM>), and a second biasing portion (<NUM>) between the third arcuate contacting surface (<NUM>) and the fourth arcuate contacting surface (<NUM>), wherein the second biasing portion (<NUM>) is biased in a second direction (<NUM>) opposite to the first direction (<NUM>) to operatively press the third arcuate contacting surface (<NUM>) against a second portion of the first drive gear shaft (<NUM>) and the fourth arcuate contacting surface (<NUM>) against a fourth portion of the second drive gear shaft (<NUM>).