CA3118359A1

CA3118359A1 - A variable torque hinge mechanism

Info

Publication number: CA3118359A1
Application number: CA3118359A
Authority: CA
Inventors: Shamanth Hampali; Anoosha PAI. S; Ananthasuresh G. K.; Hari K. V. S; Dibakar Sen
Original assignee: Indian Institute of Science IISC
Current assignee: Indian Institute of Science IISC
Priority date: 2017-12-14
Filing date: 2018-12-14
Publication date: 2019-06-20
Also published as: WO2019116340A1

Abstract

The present disclosure discloses a variable torque hinge mechanism. The mechanism comprises a pair of rigid end brackets. The hinge mechanism, further comprises a plurality of elastically deformable members, coupled to each of the pair of rigid end brackets. Furthermore, the hinge mechanism comprises a free bracket, coupled to each of the plurality of elastically deformable members, the free bracket is configured to traverse about an imaginary elastic axis of rotation (A-A). Additionally, the hinge mechanism comprises a pair of guide members positioned adjacent to the free bracket, each defining a cam profile. At least one follower, extends from the free bracket, wherein, at least one follower is configured to trace the cam profile defined on one of the pair of guide members, during a forward travel and a return travel, to attain variable 15 and customizable torque angle characteristics.

Description

TITLE: "A VARIABLE TORQUE HINGE MECHANISM"
TECHNICAL FIELD
Present disclosure generally relates to field of mechanics. Particularly but not exclusively, the present disclosure relates to a hinge mechanism. Further, embodiments of the disclosure discloses a hinge mechanism with variable and customizable torque angle characteristics.
BACKGROUND
Generally, hinge mechanisms are employed for mounting a closure means, such as but not limiting to decks, doors and any other members onto a support member. The hinge mechanism, facilitates pivot or swiveling movement between two positions such as an open position and a closed position. The hinge mechanism or simply referred to as hinge is a mechanical bearing that connects two solid objects, typically allowing only a limited angle of rotation between the objects. Conventional hinge mechanisms may include a cylinder and a pin disposed in the cylinder. The cylinder rotates around the pin during operation of the hinge. This involves rubbing of surfaces of components of the hinge, due to which friction may be generated, and thus leading to wear of the pin or the cylinder.
Conventionally, hinges are equipped with resilient members such as a torsion spring at the pivotal regions, in order to reduce the effort of the user and/or to limit the relative rotational movement between two members to a required angle of rotation. The torsion spring in the hinge may also assist in return movement upon removal of applied force.
Though the effort of the user may be reduced by using torsion spring, it can only provide linear or constant torque proportional to its angle of rotation since, the stiffness of the torsion spring is constant. However, depending on the application, the requirement of the torque-angle characteristic/profile of the hinge may vary from a constant or linear torque to a nonlinear torque value. Further, some applications may demand a variety of torque characteristic/profiles during loading and unloading conditions, which cannot be achieved by the conventional hinges, which are adapted with torsion springs.
Hence, torsion springs with different stiffness co-efficient are to be used in the hinges to meet

2 the requirement of different applications, and thus limits the usage of the hinge to a specific application.
With the on-going efforts, various mechanisms have evolved, and one such hinge mechanism is a variable torque hinge mechanism. The variable torque hinge mechanism as the name specifies is a flexible mechanism, which does not involve rubbing surfaces, unlike the conventional hinge mechanisms. Though the variable torque hinge mechanisms provide flexibility to vary the torque-angle characteristics, the range of variation of the torque-angle characteristic may be limited i.e.
these mechanisms provide more linear torque angle characteristic and less non-linear torque angle characteristic, due to rotational constraints of the components used in the hinge mechanism. Moreover, these mechanisms should be accompanied by an external bearing support member in order to vary the torque-angle characteristic within the prescribed range. However, incorporating the external bearing member in the hinge mechanism, makes the hinge mechanism bulky and expensive.
The present disclosure is directed to overcome one or more limitations stated above and any other limitations associated with the prior arts.
SUMMARY
One or more shortcomings of the prior art are overcome by a hinge mechanism as disclosed and additional advantages are provided through the hinge mechanism as described in the present disclosure.
Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
In a non-limiting embodiment of the present disclosure, a variable torque hinge mechanism [herein after referred as hinge mechanism] offers user specified torque-angle characteristic with a large range of torque is disclosed. The hinge mechanism comprises a pair of rigid end brackets. The hinge mechanism further comprises a plurality of elastically deformable members, wherein each end of each of the plurality of elastically deformable members is coupled to one of the pair of rigid end brackets.

3 Furthermore, the hinge mechanism comprises a free bracket, coupled to each of the plurality of elastically deformable members, wherein the free bracket is configured to traverse about an imaginary elastic axis of rotation (A-A). Additionally, the hinge mechanism comprises a pair of guide members positioned adjacent to the free bracket, wherein each of the pair of guide members define a cam profile. At least one follower, extends from the free bracket, wherein, at least one follower is configured to trace the cam profile defined on one of the pair of guide members, during a forward travel and a return travel, to attain variable and customizable torque angle characteristics.
In an embodiment, each of the plurality of elastically deformable members is an open section shell of variable cross-section.
In an embodiment, each of the plurality of elastically deformable members comprises a stack of open section shells.
In an embodiment, each of the plurality of elastically deformable members are configured to undergo twisting and bending, upon traversing of the free bracket about the imaginary elastic axis of rotation (A-A) of the variable torque hinge mechanism.
In an embodiment, an angle of twist of each of the plurality of elastically deformable members ranges from about 50 degrees to 90 degrees.
In an embodiment, each of the plurality of elastically deformable members are of a spring steel, Beryllium copper, polymers and carbon fibre.
In an embodiment, the free bracket is coupled on each of the plurality of elastically deformable members, at a substantially equal distance from each of the pair of rigid end brackets.
In an embodiment, the cam profiles of each of the pair of guide members are non-identical and the non-identical cam profiles of each of the pair of guide members, facilitates in attaining different torque angle characteristics during a loading cycle and an unloading cycle.
In an embodiment, the mechanism comprises an arrangement to selectively shift position of one of the pair of guide members, to contact the at least one follower.

4 It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.
The foregoing summary is illustrative only and is not intended to be in any way limiting.
In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
Figure. 1 illustrates a perspective view of a variable torque hinge mechanism, in accordance with an exemplary embodiment of the present disclosure.
Figure. 2 illustrate a perspective view of the hinge mechanism of Figure. 1 with a connection frame.
Figures. 3 illustrates a perspective view of a chair employed with the variable torque hinge mechanism of Figure. 2, in accordance with an exemplary embodiment of the present disclosure.
Figure. 4 illustrates a perspective view of a variable torque hinge mechanism, in accordance to another embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION

5 The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the description of the disclosure. It should also be realized by those skilled in the art that such equivalent methods do not depart from the scope of the disclosure. The novel features which are believed to be characteristic of the disclosure, as to the hinge mechanism, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the disclosure.
The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that the mechanism that comprises a list of acts does not include only those acts but may include other acts not expressly listed or inherent to such mechanisms. In other words, one or more acts in the mechanism

6 proceeded by "comprises.., a" does not, without more constraints, preclude the existence of other acts or additional acts in the mechanism.
Embodiments of the disclosure discloses a variable torque hinge mechanism [hereinafter referred as hinge mechanism], which offers user specified torque-angle characteristic with a range of torque values. The hinge mechanism of the present disclosure may be used in wide variety of applications, where two members or bodies are required to be connected to one other, and also to permit a relative rotational movement between the two bodies up to a certain angle. As an example, some of the applications of the variable torque hinge mechanism may include but not limiting to machine tools, robotics and automation, consumer products, exoskeletons and prostheses, home and hospital furniture, sun trackers for solar panels and the like.
The hinge mechanism according to embodiments of the disclosure may broadly comprises a pair of rigid end brackets and a plurality of elastically deformable members. Each end of the plurality of elastically deformable members is coupled to one of the pair of rigid end brackets. Further, the hinge mechanism comprises a free bracket, coupled to each of the plurality of elastically deformable members.
The free bracket is configured to traverse about an imaginary elastic axis of rotation (A-A).
Furthermore, the hinge mechanism comprises a pair of guide members, which are positioned adjacent to the free bracket. Each of the pair of guide members defines a cam profile. Additionally, the mechanism comprises at least one follower, which extends from the free bracket. The at least one follower is configured to trace the cam profile defined on one of the pair of guide members, during a forward travel and a return travel, to attain variable torque angle characteristics, during operation of the hinge mechanism.
In an embodiment, under loading condition, the free bracket coupled to each of the plurality of elastically deformable members, traverses about an imaginary elastic axis of rotation (A-A) of the hinge mechanism. As the free bracket traverses about the imaginary elastic axis of rotation (A-A), each of the plurality of elastically deformable members undergo twisting, and bending simultaneously. The at least one follower traces on one of the pair of guide members, defined with a predefined cam profile. This tracing of the at least one follower on and thus attaining a specific torque angle

7 characteristics. Further, each of the plurality of elastic deformable members undergo orthogonal bending, induced by the pair of guide members along the imaginary elastic axis of rotation (A-A).
In an embodiment, the hinge mechanism includes an arrangement, to selectively shift a position of one of the pair of guide members. The arrangement may include a lever coupled to one of the pair of rigid segments, which extends between the pair of rigid end brackets. The lever may be optionally operated to selectively shift a position of one of the pair of guide members, such that the corresponding guide member contacts the at least one follower, to attain a different and customizable torque angle characteristics during unloading. Further, during unloading, the free bracket traverses in a backward direction, about the same imaginary elastic axis of rotation (A-A).
Simultaneously, the elastically deformable members untwists and the at least one follower traces the corresponding guide member, which defines a different cam profile from that of the cam profile defined by the guide member on which the follower traces during loading condition. This facilitates in attaining a different torque angle characteristic from that of the torque angle characteristics attained during loading condition. Hence, the hinge mechanism facilitates in achieving two different and customizable torque angle characteristics in a single loading and unloading cycle.
In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying figures that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced.
These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
Figures 1 and 2 are exemplary embodiments of the disclosure illustrating perspective views of a variable torque hinge mechanism (100). The hinge mechanism (100) may broadly comprises a pair of rigid end brackets (101) and a plurality of elastically deformable members (102). In an embodiment, each of the pair of rigid end brackets (101) may include a pair of bracket halves connected by fasteners such as bolts and nuts. The bracket halves may be configured to receive an end of each of the plurality of

8 elastically deformable members (102). Each end of the plurality of elastically deformable members (102) are held and secured between the pair of bracket halves, in order to effectively couple each of the plurality of elastically deformable members (102) with each of the pair of the rigid end brackets (101). In an embodiment, each of the plurality of elastically deformable members (102) is an open section shells having a variable cross-section. Further, each of the plurality of elastically deformable members (102) may include a stack of open section shells. During operation of the hinge mechanism (100), each of the plurality of elastically deformable members (102) are configured to undergo twisting and bending about an imaginary elastic axis of rotation (A-A). In an embodiment, each of the plurality of elastically deformable members (102) are coupled to the pair of rigid end brackets (101), in a manner to achieve kinematic symmetry between each of the plurality of elastic deformable members (102). Further, each of the plurality of elastically deformable members (102) are provisioned with suitable cutouts on the geometry, and reinforcement members may be provided to facilitate equal stress distribution throughout the entire structure of the plurality of elastically deformable members (102).
In an embodiment, each of the plurality of elastically deformable members (102) are configured to serve the purpose of a nonlinear torsional spring and are designed to attain uniform and permissible stress distribution under both transverse and rotational strains.
The dimensions of the each of the plurality of elastically deformable members (102) may be selected based on value of torque-angle characteristic required for a specific application. Since, each of the plurality of elastically deformable members (102) undergo both twisting and bending. The mechanism (100) eliminates the use of external bearing support, thus making the mechanism (100) compact, modular and cost effective. Further, the hinge mechanism (100) is easy to maintain in outdoor and harsh environmental conditions. In an embodiment, each of the plurality of elastically deformable members (102) may be made of materials with high stiffness co-efficient, but not limiting to spring steel, beryllium copper, polymers, carbon fiber and the like.
The hinge mechanism (100) further comprises a free bracket (103) coupled to each of the plurality of elastically deformable members (102). The free bracket (103) is configured to traverse about an imaginary elastic axis of rotation (A-A) of the hinge mechanism (100). In an embodiment, the free bracket (103) is coupled on each of the

9 plurality of elastically deformable members (102) at a substantially equal distance from each of the pair of rigid end brackets (101). In an embodiment, traversing of the free bracket (103) about the imaginary elastic axis of rotation (A-A), results in twisting and bending of each of the plurality of elastically deformable members (102).
Further, the mechanism (100) comprises a pair of guide members (104a, 104b), which are positioned adjacent to the free bracket (103). In an embodiment, each of the pair of guide members (104a, 104b) define a cam profile. Each of the pair of guide members (104a, 104b) are removably accommodated on each of the pair of clamps (106).
Each of the pair of clamps (106) are coupled to each of a pair of rigid segments (108). As an example, each of the pair of rigid segments (108) may be bolted or welded onto the pair of rigid end brackets (101). In an embodiment, each of the pair of clamps (106) may be of any configuration such as, but not limiting to U-shape, C-shape and the like and depends on the type of application. Each of the pair of rigid segments (108) may be of any geometrical shape, but not limiting to cylindrical, square and the like.
Additionally, the hinge mechanism (100) comprises at least one follower (105), extending from the free bracket (103). In an embodiment, the follower (105) may extend from either sides of the free bracket (103). The at least one follower (105) is configured to trace the respective guide member (104a, 104b) during forward and return travel, to attain variable torque angle characteristics in a single cycle. The hinge mechanism (100) may also be configured with an arrangement, which may be configured to selectively shift position of one of the pair of guide members (104a, 104b), to contact the at least one follower (105), during loading and unloading condition.
In an embodiment, cam profile of each of the pair of guide members (104a, 104b) is not identical, and may be define with a predetermined inclination to help in achieving varying and customizable torque angle characteristics.
Since, each of the pair of guide members (104a, 104b) assists in achieving different torque-angle value, defining the profile of each of the pair of guide members (104a, 104b) is predominant. In an embodiment, the pair of guide members (104a, 104b) may include an input guide member (104a) and an output guide member (104b), which may be defined with non-identical cam profiles. The cam profile may be designed by analyzing the strain energy stored in the system for discrete bending and twisting values of each of the plurality of elastically deformable members (102), which is termed as characteristic energy. The target energy obtained by integrating the required target torque based on the application, may be mapped on to the characteristic energy data to obtain a unique cam profile for each of the guide members (104a, 104b). Thus, the profile of the guide members (104a, 104b) determines the torque-angle characteristic.
5 Hence, the hinge mechanism (100) may be provisioned in a wide variety of applications, which requires different torque-angle characteristics, by replacing the pair of guide members (104a, 104b).
During, loading, the free bracket (103) may traverse about the elastic axis of rotation (A-A), which may result in twisting of each of the pair of elastically deformable

10 members (102) and simultaneously the at least one follower (105) may trace the input guide member (104a), which have a predefined cam profile and thus attaining a specific torque angle characteristics. Further, each of the plurality of elastic deformable members (102) may undergo orthogonal bending, induced by the pair of guide members (104a, 104b).
During unloading condition, the free bracket (103) traverses in a backward direction, about the elastic axis of rotation (A-A) and each of the elastically deformable members (102) that may untwist and, simultaneously the at least one follower (105) may trace the output guide member (104b). In an embodiment, the at least one follower (105) may trace the input guide way, during unloading condition of the hinge mechanism (100).
The at least one follower (105) and each of the elastically deformable members (102) may untwist and, simultaneously at least one follower (105) may trace the output guide member (104b). In an embodiment, the at least one follower (105) may even trace the input guide member (104a), during unloading condition. The position of one of the pair guide members (140a, 104b), may be selectively shifted by the arrangement adapted in the hinge mechanism (100). The arrangement may include a lever (107) coupled to one of a pair of rigid segments (108). The lever (107) may be pivotally operated, to shift the position of the corresponding guide member to contact the at least one follower (105).
Hence, the hinge mechanism (100) facilitates to achieve two different torque-angle variations in a single loading and unloading conditions. Further, the kinematic elastic mechanics of the hinge mechanism (100) enables to achieve large rotations ranging between 50 degrees to 90 degrees with high off-axis stiffness and with optimum shift in the imaginary elastic axis of rotation (A-A).

11 In an embodiment, the mechanism (100) may be conceptualized to impart torque values ranging from a negative infinity to a positive infinity and also zero torque.
Turning to Figure 3, which illustrates a perspective view of a chair (200) employed with the variable torque hinge mechanism (100), according to one exemplary application of the present disclosure. In the chair (200) [hereinafter referred as chair], the hinge mechanism (100) may be utilized to maintain right level of resistive force while being seated and the right level of assistive force, while rising from the seated position. This facilitates in ergonomic sitting and rising from the chair (200). The mechanism (100) may be positioned on the platform (203), which is supported by a pair of front legs (202) of the chair (200). In an embodiment, the mechanism (100) may be rigidly fixed to the frame of the chair (200) by a suitable fastening arrangement or may be integrated with the frame of the chair (200). Further, a seat portion (201) of the chair (200) may be integrated with the hinge mechanism (100) through rigid structures, in order to achieve resistive and assistive forces while sitting and rising from the chair (200) respectively. In a seated position, the load may be applied on to the free bracket (103) via a link (109) (best seen in figure. 2). Due to the load applied, the free bracket (103) traverse about the imaginary axis of rotation (A-A). Due to the transverse movement of the free bracket (103), each of the plurality of elastically deformable members (102) undergo twisting and the at least one follower (105) traces a corresponding guide member (104a, 104b) simultaneously and thus offering necessary resistive force. Further, while rising from the seated position, the free bracket (103) traverses in an opposite direction about the imaginary elastic axis of rotation, resulting in untwisting of each of the plurality of elastically deformable members (102), and the follower (105) may trace an output guide member (104b) and providing necessary assistive force for rising. Hence, the hinge mechanism (100) provisioned in any of application, provides different and customizable torque-angle characteristic in a single operating cycle.
It is to be noted that, the application of the hinge mechanism (100) may not be limited to the chair (200), as the hinge mechanism (100) may be used in applications including, but not limited to robotics and automation, exoskeletons and prostheses, home and hospital furniture, and sun tracker for a solar panel.

12 Now referring to Figure. 4, which illustrates a perspective view of a variable torque hinge mechanism (100), according to an embodiment of the present disclosure.
The hinge mechanism (100) comprises a pair of building blocks (99). Each building block (99) comprises an elastically deformable member (102) such as an open-section shell (301), which is stacked and bolted rigidly between the warping restrained fixed end bracket (304) and a free end bracket (303). The free end bracket (303) of the building block (99) are connected to one another through a rigid link (302). During operation, the rigid link (302) rotates about an elastic axis (A-A). Both the building blocks (99) and the open section shells (301) share a common elastic axis (A-A). The open section shells (301) may be configured to undergo warping, twisting and bending to impart necessary stiffness to rigid link (302) during circular arc rotation of the rigid link (202) about the elastic axis (A-A). The dimensions of the open section shells (301) may be chosen based on value of torque-angle characteristic in accordance to the requirement of an application. The open section shells (301) may undergo both twisting and bending.
The hinge mechanism (100) further comprises of a pair of guide members (306a, 306b) provided on either sides, such that followers (305) coupled to free end bracket (303) traces on the guide members (306a and 306b) during loading and unloading condition.
In an embodiment, the guide members (306a and 306b) may include input guide member (306a1) and output guide member (306b) be defined with different the cam profile. The cam profile of the guide member (306a, 306b) determines the torque-angle characteristic.
It should be construed that the various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
EQUIVALENTS
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application.
The various singular/plural permutations may be expressly set forth herein for sake of clarity.

13 It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to,"
etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation, no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations.
However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one"
and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations).
Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C"
would include but not be limited to systems that have A alone, B alone, C
alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general, such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C"
would include but not be limited to systems that have A alone, B alone, C
alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word

14 and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B"
will be understood to include the possibilities of "A" or "B" or "A and B."
In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
Referral Numerals Referral Numerals Description 100 Variable torque hinge mechanism 101 Rigid end brackets 102 Plurality of elastically deformable members 103 Free bracket 104a, 104b Guide members 105 Follower 106 Clamps 107 Lever 108 Rigid segment 109 Link 200 Chair 201 Seat portion 202 Legs 203 Platform 301 Open section shells 302 Rigid link 303 Free end plate 304 Fixed end plate 305 Follower 306a, 306b Guide members

Claims

Claims:

1. A variable torque hinge mechanism (100), the mechanism (100) comprising:
a pair of rigid end brackets (101);
a plurality of elastically deformable members (102), wherein each end of each of the plurality of elastically deformable members (102) is coupled to one of the pair of rigid end brackets (101);
a free bracket (103), coupled to each of the plurality of elastically deformable members (102), wherein the free bracket (103) is configured to traverse about an imaginary elastic axis of rotation (A-A) of the variable torque hinge mechanism (100);
a pair of guide members (104) positioned adjacent to the free bracket (103) (103), wherein each of the pair of guide members (104a, 104b) define a cam profile;
and at least one follower (105), extending from the free bracket (103), wherein, at least one follower (105) is configured to trace the cam profile defined on one of the pair of guide members (104a, 104b), during a forward travel and a return travel, to attain variable and customizable torque angle characteristics.

2. The mechanism (100) as claimed in claim 1, wherein each of the plurality of elastically deformable members (102) is an open section shell of variable cross-section.

3. The mechanism (100) as claimed in claim 2, wherein each of the plurality of elastically deformable members (102) comprises a stack of open section shells.

4. The mechanism (100) as claimed in claim 1, wherein each of the plurality of elastically deformable members (102) are configured to undergo twisting and bending, upon traversing of the free bracket (103) about the imaginary elastic axis of rotation (A-A) of the variable torque hinge mechanism (100).

5. The mechanism (100) as claimed in claim 4, wherein an angle of twist of each of the plurality of elastically deformable members (102) ranges from about 50 degrees to 90 degrees.

6. The mechanism (100) as claimed in claim 1, wherein each of the plurality of elastically deformable members (102) are of a spring steel, beryllium copper, polymers and carbon fiber.

7. The mechanism (100) as claimed in claim 1, wherein the free bracket (103) is coupled on each of the plurality of elastically deformable members (102), at a substantially equal distance from each of the pair of rigid end brackets (101).

8. The mechanism (100) as claimed in claim 1, wherein the cam profiles of each of the pair of guide members (104a, 104b) are non-identical.

9. The mechanism (100) as claimed in claim 8, wherein the non-identical cam profiles of each of the pair of guide members (104a, 104b), facilitates in attaining different torque angle characteristics during a loading cycle and an unloading cycle.

10. The mechanism (100) as claimed in claim 1, comprises an arrangement to selectively shift position of one of the pair of guide members (104a, 104b), to contact the at least one follower (105).