Patent Application
20170023984
The described embodiments relate generally to computer devices. More particularly, the present embodiments relate to the use of torsion bar assemblies to exert a biasing force between hinged components in such computing devices.
Hinge assemblies are often used to allow components of a computing devices to move relative to one another. For example, a laptop computing device can be formed of a base component that is coupled to an upper display component such that the base component and upper display component share a common axis of rotation defined by a hinge assembly. It is often desirable to provide an assistive biasing force when moving the upper component of the laptop between closed and open positions. Unfortunately, a conventional friction-based hinge assembly provides a fixed resistance over a range of motion of the hinge assembly. Consequently, any variations made in the amount of resistance applies to the entire range of motion and cannot be targeted to particular portions of the range of motion or in particular directions.
This paper describes various embodiments that relate to torsion bar assemblies suitable for adjusting a resistance of pivotally coupled components.
A torsion bar assembly is disclosed that is suitable for pivotally coupling a first component to a second component of an electronic device. The torsion bar assembly includes torsion bars aligned with a common axis of rotation of the first and second components. The torsion bars have a first end coupled with the first component by way of a first securing element, and a second end coupled with the second component by way of a second securing element. Relative rotation of the first and second components with respect to each other and about the common axis of rotation induces an amount of twisting of the secured torsion bars resulting in a force that tends to oppose the relative movement of the first and second components.
A clutch assembly that pivotally couples a first component and a second component of an electronic computing device includes a first clutch component secured to the first component, a second clutch component secured to the second component and a number of torsion bars coupled to the first clutch component by a first securing element and to the second clutch component by a second securing element such that a relative movement of the first and second components about a common axis of rotation induces a rotational deformation of each of the torsion bars that resists the movement.
A method of applying an assistive force between components of a hinged electronic device is described that includes at least the following operations: coupling first ends of torsion bars to a first component such that the first ends rotate with the first component around a common axis of rotation defined by a hinge assembly, coupling second ends of the torsion bars to a second component such that the torsion bars are arranged in parallel to the common axis of rotation of the components and relative rotation between the first and second components exerts loading on the torsion bars.
The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:
Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.
The following disclosure relates to mechanical components suitable for pivotally coupling various components of an electronic device. The mechanical components can take the form of hinges. While a friction-based hinge allows pivotally coupled components of the electronic device to be maintained in any number of angular positions with respect to one another, the friction-based hinge generally provides only a consistent amount of force throughout an angular travel of the friction based hinge, i.e. the response force profile of a friction-based hinge is a constant resistive force. To vary an amount of force supplied in response to rotation of the pivotally coupled components, a torsion bar can be added to the friction-based hinge to provide one means for changing an amount of force required when rotating various portions of an electronic device. This may be desirable when the amount of force required during rotation in one direction is desired to be noticeably less than the amount of force required during rotation in another direction. Similarly, this may also be desirable when the amount of force required during rotation is desired to vary with the angle of rotation, thereby producing a varied response force profile.
Unfortunately, a torsion bar assembly that includes only one torsion bar can get prohibitively long when a design requires the torsion bar assembly to supply large amounts of force and/or angular rotation. When the length of a single bar torsion bar assembly is reduced without reducing the amount of force supplied in response to twisting the torsion bar, the amount of shear stress induced in the torsion bar is greatly increased. An increase in the shear stress induced in the torsion bar significantly reduces a range of motion that can be achieved by the torsion bar without damaging the torsion bar. Inducing shear stresses that approach or are greater than a yield strength limit of the torsion bar material can plastically deform the torsion bar, causing the torsion bar to become permanently deformed and eventually fail after enough cycles.
One way to design a torsion bar assembly having a desired size, force response, and range of motion is to utilize a torsion bar assembly that includes multiple torsion bars. By increasing the number of torsion bars in the torsion bar assembly, a reduction in the overall length and shear stress within each of the torsion bars can be reached at the cost of only a slight increase in the overall diameter of the torsion bar assembly, while maintaining the same force response. Other properties of the torsion bar assembly that can be adjusted to help optimize the torsion bar assembly include material composition of the torsion bars, the cross-sectional shape of the torsion bars, and the arrangement of the torsion bars with respect to an axis of rotation.
In some embodiments, one end of a torsion bar assembly is coupled to a base component of an electronic device such that one end of each of the torsion bars remains stationary relative to the base component. An opposite end of the torsion bar assembly is secured to an upper component of the electronic device such that the opposite end of each of the torsion bars remain stationary relative to the upper component. The torsion bars can be arranged parallel to each other, and in some embodiments each torsion bar is parallel to a common axis of rotation of the base component and the upper component. Rotation of the upper component relative to the base component subjects the torsion bar assembly to a torsional force as the torsion bar assembly is twisted by the rotation of the components with respect to one another.
In some embodiments, the torsion bars assembly includes securing elements for affixing the torsion bar assembly to the base component and the upper component. Opposing ends of each torsion bar are coupled to the upper component and the base component by way of the securing elements. Once secured to one of the components, each securing elements prevents a respective end of the torsion bars from rotating relative to the component the securing element is coupled to. In some embodiments, the individual torsion bars can be integrally formed with the securing elements during the manufacture of the torsion bars. Alternatively, the securing elements may be adhered to or otherwise mechanically coupled to the ends of the torsion bars. In some embodiments, the securing elements are integrally formed with a hinge assembly or component of an electronic device such as a base component or display component of a laptop computing device. In some embodiments, the ends of the torsion bars can have keying features that mechanically interlock with the securing elements to prevent rotation of the torsion bars with respect to the securing elements. In some embodiments, a securing element is affixed to a component in a way that allows for axial movement of the securing element relative to the axis of rotation during rotation of the components. The axial movement can prevent axial loading of the torsion bar assembly caused by the torsion bars wrapping or unwrapping about one another during torsional loading and unloading.
In further embodiments, the torsion bar assembly can be configured to adjust a resistance of a hinge assembly that defines a common axis of rotation between an upper component and a base component of an electronic device. The hinge assembly can be a friction clutch hinge assembly that exerts a uniform frictional force resistance opposing any relative rotation of the upper component relative to the base component. The torsion bar assembly and the friction clutch hinge assembly can cooperate to provide a desired feel when rotating the upper component relative to the base component. The friction clutch hinge assembly can allow the upper component to remain in a desired position relative to the base component once an external force is no longer being exerted upon the upper component. It should be noted that the torsion bars can have a cross section of various geometries. For example, the cross section can be circular, elliptical, rectangular, square, triangular, etc.
These and other embodiments are discussed below with reference to
A torsion bar assembly can be used within intersection 106 to vary an amount of force “F” required to pivot the upper component 102 relative to the base component 104. The torsion bar assembly can be configured to undergo torsional loading or unloading when the upper component 102 is rotated relative to the base component 104. As the torsion bar assembly undergoes increasing amounts of loading to resist the force “F” being applied to upper component 102 the resistance gets progressively larger with the angular rotation of the upper component 102 relative to the base component 104. As a result, if the torsion bar assembly is in an unloaded state when upper component 102 is oriented as depicted, then the torsion bar assembly can exert only minimal amounts of force when a user wants to make small adjustments to an angle at which the screen is oriented. However, when rotating upper component 102 into contact with base component 104 an amount of resistance provided by the torsion bar assembly can be maximized. This can be beneficial as it can provide additional force that can prevent inadvertent closure of computing device 100. Another advantage of this configuration is that when computing device 100 is opened, the torsion bar assembly is being unloaded as upper component 102 is rotated away from base component 104, which allows the torsion bar to reduce an amount of resistance to opening computing device 100. In this way the torsion bar makes the device easier to open than to close. It should be noted that when the torsion bar assembly includes a single torsion bar, a desired amount of resistance of the torsion bar assembly may require a torsion bar assembly that is larger than an amount of space available within intersection 106. Specifically, the length of a torsion bar assembly having a sufficient range of motion and resistance can be larger than desired. Reduction of the size of the torsion bar assembly while maintaining a desired amount of added or subtracted resistance can reduce the effective angle of rotation, or range of motion that the torsion bar assembly is capable of rotating through while maintaining the integrity of the torsion bar assembly as discussed below with respect to
As can be readily derived from Eq (1), the torque “T” required to rotate free end 120 through an angle of rotation “θ” is linearly proportional to the inverse of length “L” of torsion bar 114 and proportional to the radius “R” of the torsion bar to the fourth power. Eq (1) further shows that the torque (T) obeys Hooke's law for springs and that a solid cylindrical torsion bar has an angular spring rate “k” defined as:
The spring rate “k” of torsion bar assembly 112 determines the amount of resistance provided by torsion bar assembly 112 when subjected to torsional loading. When the spring rate “k” is constant, the resistance exerted by torsion bar assembly 112 is linearly proportional to the angular rotation “θ” of free end 120 of the torsion bar 114. When a torsion bar has a larger spring rate “k” it can provide a larger response force for a given angle of rotation “θ”.
As can be derived from Eq(1) and Eq(2), a desired response force profile of torsion bar 114 can be maintained when reducing the length “L” of the single torsion bar 114 by a specified percentage while correspondingly decreasing the radius “R” of torsion bar 114 by a substantially smaller percentage. The reduction in length “L” and proportionally smaller decrease in radius “R”, however, result in an undesirable increased shear stress induced in torsion bar 114 for a given angle of rotation “θ” when compared to a longer torsion bar 114. This increased shear stress can reduce the effective range of motion of torsion bar 114.
Eq (3) shows that the shear stress “τ” experienced by a torsion bar 114 is linearly proportional to both the shear modulus “G” of the material and the radius “R” and inversely linearly proportional to the length “L” of torsion bar 114 for a given angle of rotation “θ” as shown in the following equation:
As the shear stress induced in torsion bar 114 reaches the yield strength limit of the torsion bar material, torsion bar 114 can become permanently deformed and can eventually fail after enough cycles. Further, repeated high stress cycling of torsion bar 114 near the yield strength limit can fatigue the torsion bar material, which can also result in degradation and eventually failure of torsion bar 114. This fatiguing compounds during repeated use of torsion bar 114, as is typical in computer devices where torsion bar 114 may be required to undergo upwards of 50,000 cycles. This compounding fatiguing of torsion bar 114 reduces the life cycle of torsion bar assembly 112. While a reduction in the angle of rotation through which torsion bar 114 is allowed to rotate can reduce the induced shear stress within torsion bar 114, this reduction may prevent the torsion bar from allowing a satisfactory range of motion for the pivotally coupled components of the device.
As can be derived from the above equations, a reduction in the length “L” of a single torsion bar 114 while maintaining a desired response force profile for a given angle of deflection “θ” of the torsion bar assembly 112 will require an undesirable increase in shear stress “τ” experienced by torsion bar 114. This is because maintaining a desired spring rate “K” while reducing the length “L” of the torsion bar 114 requires a proportionally smaller decrease in the radius “R” of the torsion bar which increases the shear stress “τ”.
As should be evident from the above equations governing design modifications of a torsion bar assembly 112, options for reducing size can be very limiting. By using a torsion bar assembly with multiple torsion bars a reduction in both the length “L” of the torsion bar assembly and/or a decrease in the shear stress “τ” experienced be each of the torsion bars 114 may be achieved while maintaining the desired response force profile of the torsion bar assembly. This is because the shear stress is experienced individually by each of the torsion bars in the torsion bar assembly, allowing the response force of each of the individual torsion bars to contribute cumulatively to the response force of the torsion bar assembly. Referencing Eq (3), the radius “R” of each of the individual torsion bars in the torsion bar assembly can be reduced, thereby reducing the shear stress “τ” induced in each individual torsion bar. A torsion bar assembly that includes multiple torsion bars can generate the same amount of resistance as a torsion bar assembly with a single torsion bar while undergoing substantially less shear stress. The overall diameter of a torsion bar assembly with multiple torsion bars tends to be slightly greater than a torsion bar assembly with a single torsion bar providing a similar amount of resistance. The overall increase in diameter for the multi-bar torsion bar assembly depends on the arrangement of the torsion bars. Depending on design goals and constraints, a balance of reduction in length “L” of the torsion bar assembly, increase in radius “R” of the torsion bar assembly, and reduction in shear stress “τ” induced in each of the torsion bars for a given angular of the torsion bar assembly can be achieved while maintaining a desired amount of resistance.
Graph 200 shows that a torsion bar assembly having a single torsion bar will reach the yield strength limit of a spring steel torsion rod, 1014 MPa, at an angular deflection of about 68 degrees. Twisting this torsion bar assembly beyond an angular deflection of about 68 degrees will result in plastic deformation of the torsion bar, at which point the torsion bar becomes less reliable and more likely to experience a torsion bar failure. Rotational deformation of the torsion bar assembly below 68 degrees will result in elastic deformation of the individual torsion bars, such that the individual torsion bars return to their original shape when the torque is removed. A torsion bar assembly that includes two torsion bars of the same length and supplying the desired force response may be deflected about 81 degrees before reaching the yield strength limit of the individual torsion bars. A torsion bar assembly with four torsion bars, again of the same length and having the desired force response, may be deflected 97 degrees before reaching the yield strength limit of the individual bars. A torsion bar assembly with nine torsion bars of the same length and having the desired force response may be angularly deflected 120 degrees before reaching the yield strength limit of the individual bars.
As can be derived from graph 200, a considerable reduction in the induced shear stress can be achieved through the use of torsion bars assemblies having higher numbers of torsion bars while maintaining a desired force response of the torsion bar assembly. While these exemplary embodiments maintained a constant length for each of the torsion bar assemblies, the length, arrangement, and radii of the individual torsion bars within each of the torsion bar assemblies can be modified to achieve a satisfactory balance of induced shear stress, overall diameter, length, and desired force response of a torsion bar assembly.
The choice of material for torsion bars 302 and 304 can be varied to modify the shear modulus “G” of torsion bars 302 and 304. The material will determine the force response profiles and induced shear stress of torsion bars 302 and 304. A material having a higher shear modulus “G” will increase the stiffness and spring rate “k” of individual torsion bars 302 and 304 and provide a larger response force profile of torsion bar assembly 300. Correspondingly, torsion bars 302 and 304 formed of a material having a lower shear modulus “G” require either larger radii “R” and/or shorter lengths “L” to maintain a desired force response profile as shown in Eq. (2) above. Materials suitable for use as torsion bars 302 and 304 include iron, tool steel, spring steel, stainless steel, aluminum, brass, rubber, polymers, and carbon-fiber-reinforced polymer. Materials such as spring steel have a high modulus “G” and can allow for smaller diameter torsion bars 302 and 304 for a given spring rate “K”. In some embodiments torsion bars 302 and 304 are formed of the same material. By using the same or similar materials to form torsion bars 302 and 304 unnecessary variables that add additional stresses can be eliminated. For example, variations in thermal expansion as well as uneven distribution of shear stress between the torsion bars can be avoided.
In some embodiments, the yield strength of torsion bars 302 and 304 may vary radially. For example, torsion bars 302 and 304 may have a higher yield strength in an outer layer than a central layer of torsion bars 302 and 304. This radial variance in the yield strength can be a result of work hardening of torsion bars 302 and 304. The work hardening can occur during of the manufacturing process of torsion bars 302 and 304 or an additional process intended to alter the material of torsion bar 302 and 304. A work hardened portion of torsion bars 302 and 304 will have a higher yield strength. Since the induced shear stress of torsion bars 302 and 304 increases with radial distance from the axis of rotation and is highest at an outer layer, an increase in the yield strength of an outer layer of torsion bars 302 and 304 can increase the overall yield strength limit of torsion bars 302 and 304. This increase yield strength limit can allow for a further reduction in the size of torsion bar assembly 300.
In some embodiments, torsion bars 302 and 304 are cold worked to form the cylindrical shape of torsion bars 302 and 304. The cold working alters the crystalline structure of a circumferential outer layer of torsion bars 302 and 304. The depth of the work hardened circumferential layer can depend on the specific process used to form torsion bars 302 and 304. A volumetric percentage of torsion bars 302 and 304 that is work hardened can depend on the radii “R” of torsion bars 302 and 304 and depth “d” of the work hardening layer. Smaller radius “R” torsion bars 302 and 304 having a work hardened layer of depth “d” will have a larger percentage of their volume work hardened than larger radius torsion bars having a work hardened layer of an equal depth “d”. This increase in the yield strength of torsion bars 302 and 304 further decreases the relative shear stress that torsion bars 302 and 304 experience during use resulting in a longer cycle life of torsion bars 302 and 304.
The response force of torsion bar assembly 300 can be further modified by varying the cross-sectional shapes of torsion bars 302 and 304. In some embodiments, torsion bars 302 and 304 have circular cross-sections. In some embodiments, torsion bars 302 and 304 are hollow, and define a central bore region extending through each of the torsion bars. While torsion bars 302 and 304 may have any cross-sectional shape, cylindrical torsion bars 302 and 304 have certain advantages over other cross-sectional shapes. Shear stress induced in a cylindrical torsion bars 302 and 304 is distributed evenly over cylindrical torsion bars 302 and 304 preventing warping, or non-symmetric deformation, of torsion bars 302 and 304 when they are subjected to torsional loading. Torsion bars 302 and 304 having non-cylindrical cross-sections can concentrate shear stress in areas of torsion bars 302 and 304 due to warping of their cross-sectional shape. These stress concentrations can lead to localized fatiguing and failure of the torsion bars.
Another advantage of cylindrical torsion bars 302 and 304 is that cylindrical torsion bars 302 and 304 can be easily polished, reducing surface imperfections that can concentrate stress and cause fatiguing that can lead to degradation and failure of the torsion bars 302 and 304. Torsion bars 302 and 304 can be polished during the manufacture of torsion bars 302 and 304 or during assembly of torsion bar assembly 300. In some embodiments, torsion bars 302 and 304 are in contact along the length of the torsion bars 302 and 304. When the torsion bar assembly 300 is subjected to torsional loading, torsion bars 302 and 304 can be drawn over each other as shown in
In some embodiments, axis of rotation 306 of torsion bar assembly 300 is not positioned evenly between torsion bars 302 and 304. In such a configuration, torsion bars 302 and 304 undergo unequal bending loading as securing element 310 is rotated relative to securing element 308. Torsion bar 302 is subjected to a different amount of deflection than torsion bar 304. Torsion bar 302 can be arranged such that the deflection induced in torsion bar 302 is not minimal when compared to the torsional loading of torsion bars 302 and 304. The additional loading due to bending can reduce a required torsional loading of torsion bars 302 and 304, thus facilitating a reduction in the required radii of torsion bars 304 and 304. This reduction in the radii of torsion bar 302 and 304 can allow for a reduction in the overall diameter “D” of the torsion bar assembly 300.
In addition to undergoing torsional loading and deflection, torsion bars 302 and 304 can also undergo axial loading as they are drawn over and wrap around one another. As torsion bars 302 and 304 are drawn over each other the effective length “L” between securing elements 308 and 310 is reduced when securing elements 308 and 310 are not secured axially. In some embodiments, the securing elements 308 and 310 are secured axially, inducing axial loading as torsion bar assembly 300 is loaded. This axial loading can further contribute to the response force profile of torsion bar assembly 300. The additional response force provided by the axial loading of torsion bars 302 and 304 can facilitate a further reduction in the size of torsion bar assembly 300 since the required torsional and bending loading is reduced.
In some embodiments, ends of the torsion bars 302 and 304 are allowed to translate axially to relieve axial loading that occurs when the torsion bars 302 and 304 are drawn over one another. In some embodiments a securing element, either securing element 308 or 3010, allows the coupled torsion bars to translate axially within the securing element. In some embodiments the torsion bar ends are immobilized within securing elements 308 and 310 and either securing element 308 or securing element 310 is allowed to translate axially to relieve axial loading of torsion bar assembly 300. In some embodiments, both securing elements 308 and 310 are configured to translate axially to reduce axial loading of torsion bar assembly 300.
To further modify the spring rate and response of a torsion bar assembly, the number of torsion bars, the relative diameters of the torsion bars, and the arrangement of the torsion bars with respect to the axis of rotation can be modified as shown in
In some embodiments, torsion bars 410, 412, and 414 are arranged such that the response force profile of torsion bar assembly 403 is not linearly proportional to the angle of rotation throughout the working range of torsion bar assembly 403. Torsion bars 410, 412 and 414 are configured to come into contact during torsional loading of torsion bar assembly 403 within the working range of rotation. As torsion bar assembly 403 is rotated torsion bars 410, 412, and 414 are drawn towards the axis of rotation and at a predetermined angle torsion bars 410, 412, and 414 contact one another. As torsion bars 410, 412 and 414 contact each other during rotation of torsion bar assembly 403, a bending loading rate for each torsion bar is modified altering the spring rate of torsion bar assembly 403 at this angle of rotation. The response profile of torsion bar assembly 403, therefore, is not linearly proportional to the angle of rotation at this predetermined angle where torsion bars 410, 412, and 414 make contact during rotation. Such a configuration can be advantageous when a substantial increase in resistance is desirable for a particular design.
In some embodiments, torsion bars having varying radii can be arranged in a torsion bar assembly such that the overall diameter of the torsion bar assembly is no greater than a combination of the two largest diameter torsion bars.
In some embodiments one of the torsion bars can be aligned with the axis of rotation of the torsion bar assembly.
In some embodiments, torsion bars can be arranged such that the loading of the torsion bar assembly is asymmetric. The spring rate and response of a torsion bar assembly can be modified through asymmetrically shifting the bending and torsional loads induced in the torsion bars around the axis of rotation.
In some embodiments torsion bars are restrained by securing elements that are configured to couple the torsion bar assembly to opposing major components of an electronic device. Torsion bars can be coupled to the securing elements in any way that prevents rotation of the torsion bars when the torsion bar assembly is subjected to a torsional load. Securing methods can include adhesive, press fitting, and features designed into the torsion bars and corresponding securing elements. In some embodiments, the torsion bars can have engagement features that are configured to couple the torsion bars to the securing elements.
Certain engagement element designs can be simpler to manufacture, such as keyed slot engagement elements 506 and 508 that can be formed during the manufacturing process of torsion bars 502 and 504. In some embodiments, engagement elements 506 and 508 are cut into the ends of torsion bars 502 and 504 during the formation of torsion bars 502 and 504. In some embodiments, torsion bars 502 and 504 are configured to be easily decoupled from securing element 510. Decoupling of torsion bars 502 and 504 from securing element 510 can allow for the installation and removal of torsion bar assembly 501. In other embodiments, torsion bars 502 and 504 can be permanently coupled to securing element 510. Torsion bars 502 and 504 can be permanently coupled by glue, adhesive, welding, press fitting, or permanently coupling features.
In some embodiments, engagement features may be formed symmetrically around the circumference of the ends of torsion bars to allow for multiple engagement positions.
A torsion bar assembly can be combined with a hinge assembly as shown in
In some embodiments, clutch hinge assembly 601 includes an outer clutch component 604 configured to house an inner clutch component 606 such that friction between the inner clutch component 606 and the outer clutch component 604 modifies a user feel of the hinge assembly. Outer clutch component 604 is coupled to a first component of an electrical device, and inner clutch component 606 is coupled to a second component of the electrical device such that the first and second major components share an axis of rotation 602. Clutch hinge assembly 601 can provide a consistent force against the relative rotation of major components of an electronic device. First ends of torsion bars 608 and 610 can be coupled to a portion of clutch hinge assembly 601 that is secured to a first component of an electronic device and second ends of torsion bars 608 and 610 are coupled to a second component of the electronic device such that relative motion between the major components loads the torsion bar assembly 603.
Torsion bar assembly 603 can include securing element 612 at a first end of torsion bar assembly 603. In some embodiments, outer clutch component 604 can be coupled to securing element 612 such that securing element 612 rotates with outer clutch component 604 when a first major component of an electronic device is rotated. In some embodiments, securing element 612 can be coupled to the inner clutch component 606 such that securing element 612 rotates with inner clutch component 606 when a first major component of the electronic device is rotated. A second end of torsion bar assembly 603 can be coupled to a second major components of the electric device such that the second end rotates with the second major component of the electronic device when major components are rotated around the axis of rotation 602.
In some embodiments, the clutch hinge assembly can have a hollow portion allowing the torsion bar assembly to pass through as shown in
In some embodiments, inner clutch component 702 can be circular in nature, and can have an annular outer region and a central bore region 706 surrounded by the annular outer region. The central bore region 706 can be adapted to permit the passage of the torsion bar assembly 701. In some embodiments, torsion bar assembly 701 passes through central bore region 706 and is coupled to the clutch hinge assembly 700. Clutch hinge assembly 700 can be configured to couple to a first end of torsion bar assembly 701. The first end of the torsion bar assembly 701 can include a securing element 708 that couples to inner clutch component 702. In some embodiments, the coupling of securing element 708 to the inner clutch component 702 allows for axial translation of securing element 708 to alleviate axial loading of torsion bar assembly 701 when torsion bar assembly 701 is loaded. A second end of torsion bar assembly 701 is configured such that the second end rotates with the outer clutch component 704.
In some embodiments, the second end of torsion bar assembly 701 is coupled to the outer clutch component 704 as shown in
In some embodiments, torsion bar assembly 701 is configured to be in an unloaded state in a designated range of rotation of the hinge assembly. The coupling element 711 of securing element 709 can allow for rotation of securing element 709 within this designated range of rotation of the hinge assembly, thereby preventing the loading of the torsion bar assembly within this designated range. In a laptop computing device, for example, torsion bar assembly 701 can be configured to be in an unloaded state when the display of the laptop is rotated in a range between the fully closed and fully open states. The coupling element 711 of the securing element can engage the securing element 709 when the laptop display is proximate the closed and fully open states, thereby providing a biasing assistive force only when the laptop display is proximate the fully closed or fully open states. The friction clutch hinge assembly 700 and the torsion bar assembly 703 can cooperate to produce a response force profile having a neutral range where only the friction clutch hinge assembly contributes to the response force profile.
In step 804, an opposite end of each of the torsion bars is coupled to a second component. In some embodiments, the opposite end is coupled directly to the second component, while in other embodiments the opposite end is first coupled to a securing element. The securing element can be made of any material suitable for securely holding the ends of the torsion bars. Suitable materials include steel, aluminum, brass, and copper, and polymers. In some embodiments, the torsion bars are arranged such that they undergo a combined torsional and bending loading when the major components are rotated relative to on another around a common axis. The common axis can be defined by a hinge mechanism that couples the components together.
The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not target to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.
