Patent Publication Number: US-11041335-B2

Title: Hinge

Description:
FIELD 
     The disclosure relates to a hinge, and more particularly to an adjustable hinge. 
     BACKGROUND 
     A conventional hinge disclosed in Taiwanese Patent No. 1580856 includes a leaf unit that has first and second leaves that are rotatable relative to each other, and two action modules that are mounted in the leaf unit. Each of the action modules includes a casing that is co-rotatable with the first leaf, and an operating shaft that is co-rotatable with the second leaf. The casing and the operating shaft of each of the action modules are rotated relative to each other upon the relative rotation between the first and second leaves, so as to generate an actuating force that acts between the first and second leaves. 
     However, to co-rotatably mount the operating shaft of each of the action modules to the second leaf, an inner surrounding surface of the second leaf need to be formed with mounting structures that correspond to the operating shafts of the action modules. Such mounting structures may not be machined easily. 
     SUMMARY 
     Therefore, an object of the disclosure is to provide a hinge that can alleviate the drawback of the prior art. 
     According to the disclosure, the hinge is adapted to interconnect first and second objects, and includes a leaf unit, two action units and an axle unit. The leaf unit includes first and second leaves that are rotatable relative to each other. The first leaf has at least one first barrel. The second leaf has at least one second barrel that is spaced apart from the first barrel along an axis. The action units are inserted into the first barrel and the second barrel respectively in two opposite directions along the axis, and are co-rotatable with the first leaf. The axle unit includes a fixing member that is mounted in the second barrel of the second leaf and that is co-rotatable with the second leaf, and two axle constituents that are respectively associated with the action units and that are co-rotatable with the fixing member. Each of the axle constituents and the corresponding action unit are rotated relative to each other upon relative rotation between the first and second leaves so that the corresponding action unit generates an actuating force that acts between the first and second leaves. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the disclosure will become apparent in the following detailed description of the embodiments with reference to the accompanying drawings, of which: 
         FIG. 1  is a top view illustrating a first embodiment of the hinge according to the disclosure; 
         FIG. 2  is a partly exploded perspective view illustrating the first embodiment; 
         FIG. 3  is an exploded perspective view illustrating a first action unit of the first embodiment; 
         FIG. 4  is a sectional view illustrating the first action unit; 
         FIG. 5  is an exploded perspective view illustrating a second action unit of the first embodiment; 
         FIG. 6  is a sectional view illustrating the second action unit; 
         FIG. 7  is an assembled perspective view illustrating the first embodiment; 
         FIG. 8  is a sectional view illustrating the first embodiment; 
         FIG. 9  is a partly exploded perspective view illustrating a second embodiment of the hinge according to the disclosure; 
         FIG. 10  is an exploded perspective view illustrating one of two torsional action units of the second embodiment; 
         FIG. 11  is a sectional view illustrating the one of the torsional action units; 
         FIG. 12  is an exploded perspective view illustrating the other one of the torsional action units of the second embodiment; 
         FIG. 13  is a sectional view illustrating the other one of the torsional action units; 
         FIG. 14  is an assembled perspective view illustrating the second embodiment; 
         FIG. 15  is a sectional view illustrating the second embodiment; 
         FIG. 16  is a sectional view illustrating a third embodiment of the hinge according to the disclosure; 
         FIG. 17  is a sectional view illustrating a fourth embodiment of the hinge according to the disclosure; 
         FIG. 18  is a sectional view illustrating a modification of the first action unit; 
         FIG. 19  is a partly exploded perspective view illustrating a fifth embodiment of the hinge according to the disclosure; 
         FIG. 20  is a sectional view illustrating the fifth embodiment; 
         FIG. 21  is a partly exploded perspective view illustrating a sixth embodiment of the hinge according to the disclosure; 
         FIG. 22  is a sectional view illustrating the sixth embodiment; 
         FIG. 23  is a partly exploded perspective view illustrating a modification of a ring unit of the hinge according to the disclosure; 
         FIG. 24  is a sectional view illustrating the modification of the ring unit; 
         FIG. 25  is a sectional view illustrating a modification of the torsional action unit of the hinge according to the disclosure; and 
         FIGS. 26 and 27  are sectional views illustrating operation of the modification of the torsional action unit. 
     
    
    
     DETAILED DESCRIPTION 
     Before the disclosure is described in greater detail, it should be noted that where considered appropriate, reference numerals or terminal portions of reference numerals have been repeated among the figures to indicate corresponding or analogous elements, which may optionally have similar characteristics. 
     Referring to  FIGS. 1 and 2 , the first embodiment of the hinge according to the disclosure is for interconnecting first and second objects  11 ,  12  (e.g., a door frame and a door leaf), and includes a leaf unit  2 , a first action unit  6 , a second action unit  7 , an axle unit  4  and a ring unit  5 . 
     The leaf unit  2  includes first and second leaves  21 ,  22  that are rotatable relative to each other. Each of the first leaf  21  and the second leaf  22  is made of metal. 
     In one embodiment, the first leaf  21  has two first barrels  211  that are spaced apart from each other along an axis (X), a first clinging surface  212  that clings to the first object  11 , and a first positioning surface  213  that is parallel to the axis (X), that is connected to the first clinging surface  212  and that is not coplanar with the first clinging surface  212 . The first positioning surface  213  permits an edge  111  of the first object  11  to abut thereagainst. Each of the first barrels  211  has two inner limiting planes  2111  that are formed on an inner surrounding surface thereof. 
     The second leaf  22  has a second barrel  221  that is disposed between the first barrels  211  and that is spaced apart from the first barrels  211  along the axis (X), a second clinging surface  222  that clings to the second object  12 , and a second positioning surface  223  that is parallel to the axis (X), that is connected to the second clinging surface  222  and that is not coplanar with the second clinging surface  222 . The second positioning surface  223  permits an edge  121  of the second object  12  to abut thereagainst. 
     Referring further to  FIGS. 3 and 4 , the first action unit  6  includes a first tubular member  61  that is inserted into the first and second barrels  211 ,  221  and that is co-rotatable with the first leaf  21 , a hydraulic module  62  that is disposed in the first tubular member  61 , a distal acting member  63  that is co-rotatably mounted in the first tubular member  61 , a proximal acting member  64  that is co-rotatably mounted in the first tubular member  61 , and a cap member  65  that is mounted to an end of the first tubular member  61 . 
     The first tubular member  61  has a first tube section  611 , and a second tube section  612  that abuts against the first tube section  611 . The first tube section  611  has two outer limiting planes  6111  that are formed at an outer surrounding surface thereof and that respectively abut against the inner limiting planes  2111  of one of the first barrels  211 , and two mounting grooves  6112  each of which extends from an end of the first tube section  611  in the direction of the axis (X). The second tube section  612  has two outer limiting planes  6121  that are formed at an outer surrounding surface thereof and that respectively abut against the inner limiting planes  2111  of one of the first barrels  211 , two spaced-apart positioning recesses  6122  that are formed in an inner surrounding surface thereof, and two mounting grooves  6123  each of which extends from an end of the second tube section  612  in the direction of the axis (X). Each of the mounting grooves  6112  of the first tube section  611  cooperates with a respective one of the mounting grooves  6123  of the second tube section  612  to form a mounting space  610  (see  FIG. 4 ). By such, the first tubular member  61  is co-rotatable with the first leaf  21  by the cooperation among the outer limiting planes  6111 ,  6121  and the inner limiting planes  2111 . It should be noted that the two-piece first tubular member  61  is easy to be assembled with other components, and the first and second tube sections  611 ,  612  can be made of different materials. A junction between the first and second tube sections  611 ,  612  of the first tubular member  61  should be located within one of the first barrels  211 . 
     The hydraulic module  62  includes a hydraulic cylinder  621 , an abutment pin  622  that abuts against the hydraulic cylinder  621 , and a resilient member  623  that abuts against the hydraulic cylinder  621 . The hydraulic cylinder  621  threadably engages the first tube section  611  of the first tubular member  61 , and has a hexagonal setting hole  6211  that extends along the axis (X) and that is accessible through the cap member  65 , a hexagonal throttle hole  6212 , and a telescopic protrusion  6213  that is opposite to the setting hole  6211  and that abuts against the abutment pin  622 . 
     The distal acting member  63  is mounted to the first and second tube sections  611 ,  612  of the first tubular member  61 , and has a distal inclined surface  631 , and two mounting blocks  632  each of which engages a respective one of the mounting grooves  6112  of the first tube section  611  and a corresponding one of the mounting grooves  6123  of the second tube section  612  (i.e., resides within a respective one of the mounting spaces  610 ), so that the distal acting member  63  is co-rotatable with the first tubular member  61 . 
     The proximal acting member  64  has a proximal inclined surface  641 , a through hole  642 , and two spaced-apart positioning protrusions  643  that are formed on an outer surrounding surface thereof. The positioning protrusions  643  of the proximal acting member  64  respectively engage the positioning recesses  6122  of the second tube section  612 , so that the proximal acting member  64  is co-rotatable with the first tubular member  61 . 
     Referring further to  FIGS. 5 and 6 , the second action unit  7  includes a second tubular member  71  that is inserted into the first and second barrels  211 ,  221  and that is co-rotatable with the first leaf  21 , a disc spring assembly  72  that is disposed in the second tubular member  71 , a friction member  73  that abuts against the disc spring assembly  72  and that is co-rotatable with the second tubular member  71 , an adjusting member  74  that engages threadably the second tubular member  71  and that pushes the disc spring assembly  72 , and a plurality of washers  75  disposed in the second tubular member  71 . In this embodiment, the second action unit  7  includes two tab washers  75 . 
     The second tubular member  71  has a first tube section  711 , and a second tube section  712  that abuts against the first tube section  711 . The first tube section  711  has two outer limiting planes  7111  (only one is visible in  FIG. 5 ) that are formed at an outer surrounding surface thereof and that respectively abut against the inner limiting planes  2111  of one of the first barrels  211 , and two mounting blocks  7112  each of which extends from an end of the first tube section  711  in the direction of the axis (X). The second tube section  712  has two outer limiting planes  7121  that are formed at an outer surrounding surface thereof and that respectively abut against the inner limiting planes  2111  of one of the first barrels  211 , two spaced-apart positioning recesses  7122  (only one is shown in  FIG. 5 ) that are formed at an end of the second tube section  712 , and two spaced-apart mounting grooves  7123  each of which extends from an opposite end of the second tube section  712  in the direction of the axis (X) and is engaged with a respective one of the mounting blocks  7112  of the first tube section  711 . 
     The disc spring assembly  72  includes a plurality of disc springs  721  that are disposed between the friction member  73  and one of the washers  75 , and a padding member  722  that is disposed between the washers  75 . The friction member  73  has two spaced-apart positioning protrusions  731  that are formed on an outer surrounding surface thereof and that respectively engage the positioning recesses  7122  of the second tube section  712  so that the friction member  73  is co-rotatable with the second tubular member  71 . The friction member  73  further has a friction surface  732  that is formed at an end thereof distal from the disc spring assembly  72 . 
     By such, the second tubular member  71  is co-rotatable with the first leaf  21  by the cooperation among the outer limiting planes  7111 ,  7121  and the inner limiting planes  2111 . It should be noted that the two-piece second tubular member  71  is easy to be assembled with other components, and the first and second tube sections  711 ,  712  can be made of different materials. A junction between the first and second tube sections  711 ,  712  of the second tubular member  71  should be located within one of the first barrels  211 . 
     Referring back to  FIGS. 2 and 3 , in this embodiment, the axle unit  4  includes a fixing member that is removably mounted in the second barrel  221  of the second leaf  22  by a fastener  23  and that is co-rotatable with the second leaf  22 , a first axle constituent  43  (see  FIG. 3 ) that is mounted to the first action unit  6  and that is co-rotatably connected to the fixing member  41 , and a second axle constituent  44  (see  FIG. 2 ) that is mounted to the second action unit  7  and that is co-rotatably connected to the fixing member  41 . In one embodiment, the first axle constituent  43  is located between the fixing member  41  and the hydraulic cylinder  621 . 
     The fixing member  41  has a rectangular fixing hole  411  that is formed in one of two opposite end surfaces of the fixing member  41  along the axis (X) and that extends along the axis (X), a fixing recess  412  (see  FIG. 8 ) that is formed in the other one of the opposite end surfaces of the fixing member  41 , and two fixing grooves  413  (only one is visible in  FIG. 2 ) that are respectively formed in the opposite end surfaces of the fixing member  41 . In one embodiment, the fixing recess  412  is configured as a circular recess. In one embodiment, the fixing hole  411  is formed through the opposite end surfaces of the fixing member  41 . In one embodiment, the fixing member  41  has a circular outer surrounding surface that abuts against an inner surrounding surface of the second barrel  221  of the second leaf  22 . 
     Referring back to  FIG. 3 , the first axle constituent  43  has a follower portion  430  that is disposed between the distal acting member  63  and the proximal acting member  64 , and an axle portion  431  that extends through the through hole  642  of the proximal acting member  64  and that co-rotatably engages the fixing hole  411  of the fixing member  41 . The follower portion  430  has an abutment surface  432  (see  FIG. 8 ) that is opposite to the axle portion  431  and that abuts against the abutment pin  622  and the resilient member  623 , a surrounding wall  433  that cooperates with the abutment surface  432  to define a recess, and a proximal follower surface  434  that is opposite to the abutment surface  432  and that faces toward the proximal inclined surface  641  of the proximal acting member  64 . The surrounding wall  433  has a distal follower surface  4331  that is opposite to the proximal follower surface  434  and that faces toward the distal inclined surface  631  of the distal acting member  63 . In this embodiment, the axle portion  431  has configured as a rectangular cross-section. 
     Referring to  FIG. 2 , the second axle constituent  44  has a fixing hole  440  that is co-rotatably engaged with the axle portion  431  of the first axle constituent  43 , a post  441  that co-rotatably engages a corresponding one of the fixing grooves  413  of the fixing member  41 , and two protrusions  442  (only one is visible in  FIG. 2 ) that protrude toward the friction surface  732  of the friction member  73  of the second action unit  7 . In this embodiment, the fixing hole  440  is configured as a rectangular hole. The post  441  may co-rotatably engages the fixing recess  412  of the fixing member  41  by modifying the shape of the fixing recess  412 . The protrusions  442  of the second axle constituent  44  are in frictional contact with the friction surface  732  of the friction member  73  of the second action unit  7 , so that the second action unit  7  may generate an actuating force that acts between the first and second leaves  21 ,  22  when the second axle constituent  44  and the second action unit  7  are rotated relative to each other. The profile of the friction surface  732  of the friction member  73  may be configured such that the first and second leaves  21 ,  22  are held relative to each other when an angle formed between the first and second leaves  21 ,  22  reaches a predetermined value or range, or may be configured such that the second action unit  7  retards the relative rotation between the first and second leaves  21 ,  22  when the angle formed between the first and second leaves  21 , reaches a predetermined value or range, and is not limited to such. 
     Referring to  FIGS. 2 and 8 , the ring unit  5  includes two ring members  51  and two spacer assemblies  52 . The ring members  51  are respectively disposed between the first tubular member  61  and the second barrel  221  and between the second tubular member  71  and the second barrel  221 . Each of the spacer assemblies  52  includes a spacer  521 . Each of the spacers  521  of the spacer assemblies  52  has an surrounding wall  522  that is disposed between the second barrel  221  and a respective one of the first tubular member  61  and the second tubular member  71 , and a flange wall  523  that is disposed between the second barrel  221  and a respective one of the first barrels  211 . Each of the ring members  51  and the spacer assemblies  52  may be made of Polyoxymethylene (POM) or Polytetrafluoroethylene (PTFE), and serves as a bushing for facilitating relative rotation between the corresponding components. 
     During installation of the hinge onto the first and second objects  11 ,  12 , the first leaf  21  can be quickly and accurately positioned relative to the first object  11  by moving the first positioning surface  213  to abut against the edge  111  of the first object  11 , and the second leaf  22  can be quickly and accurately positioned relative to the second object  12  by moving the second positioning surface  223  to abut against the edge  121  of the second object  12 . As such, the first and second objects  11 ,  12  are accurately positioned relative to each other, and can be smoothly rotated relative to each other. 
     Referring to  FIGS. 1 to 8 , when the first and second leaves  21 ,  22  are rotated relative to each other in the direction of the arrow shown in  FIG. 1  by an external force, the first axle constituent  43  is rotated relative to the distal and proximal acting members  63 ,  64 , and the proximal inclined surface  641  of the proximal acting member  64  pushes the proximal follower surface  434  of the first axle constituent  43  to move the first axle constituent  43  toward the hydraulic cylinder  621  and to push the distal follower surface  4331  against the distal inclined surface  631  of the distal acting member  63 . As such, the first axle constituent  43  pushes the abutment pin  622  to press the telescopic protrusion  6213  of the hydraulic cylinder  621  for controlling the relative rotational speed between the first and second leaves  21 ,  22 , and the abutment surface  432  of the first axle constituent  43  pushes and compresses the resilient member  63  to generate a restoring force (i.e., an actuating force). 
     At the same time, the second axle constituent  44  is rotated relative to the friction member  73 , and pushes the friction member  73  to compress the disc spring assembly  72  to generate the actuating force. 
     When the external force is removed, the resilient member  623  pushes the first axle constituent  43  to move away from the hydraulic cylinder  621 , and therefore the proximal follower surface  434  of the first axle constituent  43  pushes the proximal inclined surface  641  of the proximal acting member  64  to rotate the first axle constituent  43  and the proximal acting member  64  relative to each other, so as to rotate the first and second leaves  21 ,  22  relative to each other in a direction opposite to the arrow shown in  FIG. 1 . 
     It should be noted that, in one embodiment, the distal follower surface  4331  of the first axle constituent  43  is in contact with the distal inclined surface  631  of the distal acting member  63  when the first and second leaves  21 ,  22  are rotated relative to each other in the direction opposite to the arrow shown in  FIG. 1 . 
     It should also be noted that, the first leaf  21  can be connected to any one of a door leaf and a door frame while the second leaf  22  is connected to the other one of the door leaf and the door frame. 
     The hexagonal setting hole  6211  of the hydraulic cylinder  621  permits a hand tool to engage therewith. By rotating the hand tool, the hydraulic cylinder  621  is moved relative to the first tubular member  61  along the axis (X), and the relative position between the hydraulic cylinder  621  and the first axle constituent  43  is adjusted, so that the range of the angle formed between the first and second leaves  21 ,  22  within which the hydraulic cylinder  621  works can be adjusted. The hexagonal throttle hole  6212  of the hydraulic cylinder  621  permits another hand tool to engage therewith. By rotating the hand tool, the damping coefficient of the hydraulic cylinder  621  can be adjusted. 
     In addition, by moving the adjusting member  74  along the axis (X), the actuating force generated by the disc spring assembly  72  can be adjusted. By substituting the friction member  73  with another friction member  73  that has a friction surface  732  with different profile, the disc spring assembly  72  is able to generate the actuating force when the angle formed between the first and second leaves  21 ,  22  reaches a predetermined value or range. 
     Referring to  FIGS. 9 and 10 , a second embodiment of the hinge according to the disclosure is similar to the first embodiment, and includes the leaf unit  2 , the axle unit  4 , the ring unit  5 , and two torsional action units  3 . 
     In this embodiment, the first leaf  21  is U-shaped and defines a receiving space, and the second leaf  22  is disposed in the receiving space of the first leaf  21 . 
     Referring to  FIGS. 10 to 13 , the torsional action units  3  are inserted into the first barrels  211  and the second barrel  221  respectively in two opposite directions along the axis (X). Each of the torsional action units  3  includes a torsional tubular member  31  that is inserted into the first and second barrels  211 ,  221  and that is co-rotatable with the first leaf  21 , a torsion spring  32  that is disposed in the torsional tubular member  31  for generating a restoring force, an adjusting member  33  that is rotatably disposed in the torsional tubular member and that can be positioned relative to the torsional tubular member  31 , two limiting rings  34  (see  FIGS. 11 and 12 ), and a set screw  35 . 
     The torsional tubular member  31  has a first tube section  311 , and a second tube section  312  that abuts against the first tube section  311 . The first tube section  311  has a toothed portion  3111  formed at an inner surrounding surface thereof, two mounting blocks  3112  each of which extends from an end of the first tube section  311  in the direction of the axis (X), and two outer limiting planes  3113  (only one is visible in  FIG. 10 ) that are formed at an outer surrounding surface thereof and that respectively abut against the inner limiting planes  2111  of one of the first barrels  211 . The second tube section  312  has two spaced-apart mounting grooves  3121  each of which extends from an end of the second tube section  312  in the direction of the axis (X) and is engaged with a respective one of the mounting blocks  3112  of the first tube section  311 , and two outer limiting planes  3122  that are formed at an outer surrounding surface thereof and that respectively abut against the inner limiting planes  2111  of one of the first barrels  211 . 
     The torsion spring  32  has a middle coil  324 , two end coils  323  that are respectively connected to two opposite ends of the middle coil  324 , and two end portions  321 ,  322  each of which is connected to a distal end of a respective one of the end coils  323 . Each of the end coils  323  has at least two spirals that are spaced apart from each other by a first distance (D 1 ). The middle coil  324  has a plurality of spirals. Two adjacent ones of the spirals of the middle coil  324  are spaced apart from each other by a second distance (D 2 ). The first distance (D 1 ) is smaller than the second distance (D 2 ). 
     The adjusting member  33  has a hexagonal adjusting hole  331  (see  FIG. 11 ) that is formed in an end surface thereof and that is exposed from the torsional tubular member  31 , a limiting groove  332  that is formed in an outer surrounding surface thereof, a toothed portion  333  that separably engages the toothed portion  3111  of the first tube section  311 , and a spring groove  334  that is formed in an end surface thereof and that is co-rotatably engaged with the end portion  321  of the torsion spring  32 . The hexagonal adjusting hole  331  of the adjusting member  33  permits a hand tool (not shown) to engage therewith. By rotating the hand tool in a direction, the engagement between the toothed portion  333  of the adjusting member  33  and the toothed portion  3111  of the first tube section  311  can be adjusted so as to adjust the restoring force (i.e., an actuating force) generated by the torsion spring  32 . 
     The limiting rings  34  are respectively disposed between the first tube section  311  and the second tube section  312  and at an end of the second tube section distal from the first tube section  311 , and respectively surrounds the end portions  321 ,  322  of the torsion spring  32  to prevent the end portions  321 ,  322  of the torsion spring  32  from being separated from the spring groove  334  of the adjusting member  33 . The set screw  33  engages threadedly the first tube section  311  of the torsional tubular member  31 , and extends into the limiting groove  332  of the adjusting member  33  to limiting movement of the adjusting member  33  along the axis (X). 
     Referring to  FIGS. 9, 10 and 12 , the axle unit includes a fixing member  41  that is removably mounted in the second barrel  221  of the second leaf  22  by a fastener  23  (see  FIG. 15 ) and that is co-rotatable with the second leaf  22 , two torsional axles  42  (see  FIGS. 10 and 12 ) each of which is mounted to a respective one of the torsional action units  3  and is co-rotatably connected to the fixing member  41 . 
     The fixing member  41  has a rectangular fixing hole  411  that is formed in one of two opposite end surfaces of the fixing member  41  along the axis (X) and that extends along the axis (X), a fixing recess  412  (see  FIG. 9 ) that is formed in the other one of the opposite end surfaces of the fixing member  41 , and two fixing grooves  413  (only one is visible in  FIG. 9 ) that are respectively formed in the opposite end surfaces of the fixing member  41 . In one embodiment, the fixing recess  412  is configured as a rectangular recess. In one embodiment, the fixing hole  411  is formed through the opposite end surfaces of the fixing member  41 . 
     Each of the torsional axles  42  extends along the axis (X) through the end coils  323  and the middle coil  324  of the torsion spring  32  of the corresponding torsional action unit  3 , and has an axle portion  421 , and a flange portion  423  that is formed with a breach  422 . The axle portions  421  of the torsional axles  42  respectively and co-rotatably engage the fixing hole  411  and the fixing recess  412  of the fixing member  41  (see  FIG. 15 ). The breaches  422  of the torsional axles  42  are respectively aligned with the fixing grooves  413  of the fixing member  41 , so that the end portions  322  of the torsion springs  32  of the torsional action units  3  respectively extend through the breaches  422  of the torsional axles  42  to respectively engage the fixing grooves  413  of the fixing member  41 . 
     Referring to  FIG. 14 , since the second leaf  22  is disposed in the receiving space defined by the U-shaped first leaf  21 , the second embodiment is suitable for use on the occasion that a gap between the first and second objects  11 ,  12  (with reference to  FIG. 1 ) is equal to or slightly greater than the thickness of the first leaf  21 . During installation of the hinge onto the first and second objects  11 ,  12 , the first leaf  21  can be quickly and accurately positioned relative to the first object by moving the first positioning surface  213  to abut against the edge  111  of the first object  11 , and the second leaf  22  can be quickly and accurately positioned relative to the second object  12  by moving the second positioning surface  223  to abut against the edge  121  of the second object  12 . As such, the first and second objects  11 ,  12  are accurately positioned relative to each other, and can be smoothly rotated relative to each other. 
     Referring to  FIGS. 9, 14 and 15 , when the first and second leaves  21 ,  22  are rotated relative to each other by an external force, each of the torsional axles  42  is rotated relative to the torsional tubular member  31  of the corresponding torsional action unit  3  to twist the torsion spring  32  of the corresponding torsional action unit  3  in a direction such that the diameter of the torsion spring  32  decreases and that each of the first and distances (D 1 , D 2 ) decreases so as to generate a restoring force (i.e., an actuating force). By such, when the external force is removed, the torsion spring  32  of each of the torsional action units  3  restores to rotate the first and second leaves  21 ,  22  relative to each other. 
     The second embodiment employs two torsion springs  32  to generate the restoring force, and is therefore suitable for a heavy door leaf. It should be noted that after the torsion spring  32  is twisted by an external force such that any two adjacent ones of the spirals of each of the end coils  323  abut against each other (i.e., D 1 =0, D 2 ≠0), further relative rotation between the corresponding adjusting member  33  and the corresponding torsional axle  42  caused by the external force would only deform the middle coil  324  (because the end coils  323  cannot be further deformed). Accordingly, in the case that each of the middle coil  324  and the end coils  323  has the same number of spirals, upon each relative rotation between the corresponding adjusting member  33  and the corresponding torsional axle  42  by a predetermined angle caused by the external force, the increment of the restoring force generated by the torsion spring  32  at the time that any two adjacent ones of the spirals of each of the end coils  323  abut against each other is three times the increment of the restoring force generated by the torsion spring  32  at the time that the spirals of each of the end coils  323  are spaced apart from each other. As such, the second embodiment is suitable for a heavy door leaf. 
     It should be noted that the first leaf  21  can be connected to any one of a door leaf and a door frame while the second leaf  22  is connected to the other one of the door leaf and the door frame. 
     Referring to  FIG. 16 , a third embodiment of the hinge according to the disclosure is similar to the second embodiment, and includes the leaf unit  2 , the axle unit  4 , the ring unit  5 , the torsional action unit  3  and the second action unit  7 . The axle unit  4  of the third embodiment includes the fixing member that is removably mounted in the second barrel  221  of the second leaf  22  by the fastener  23  and that is co-rotatable with the second leaf  22 , the torsional axle  42  that is mounted to the torsional action unit  3  and that is co-rotatably connected to the fixing member  41 , and the second axle constituent  44  that is mounted to the second action unit  7  and that is co-rotatably connected to the fixing member  41 . 
     The cooperation of the components of the third embodiment can be comprehended by one of ordinary skill in the art with reference to the preceding paragraphs, and would not be further described. 
     Referring to  FIG. 17 , a fourth embodiment of the hinge according to the disclosure is similar to the second embodiment, and includes the leaf unit  2 , the axle unit  4 , the ring unit  5 , the torsional action unit  3  and the first action unit  6 . The axle unit  4  of the fourth embodiment includes the fixing member  41  that is removably mounted in the second barrel  221  of the second leaf  22  by the fastener  23  and that is co-rotatable with the second leaf  22 , the torsional axle  42  that is mounted to the torsional action unit  3  and that is co-rotatably connected to the fixing member  41 , and the first axle constituent  43  that is mounted to the first action unit  6  and that is co-rotatably connected to the fixing member  41 . 
     The cooperation of the components of the fourth embodiment can be comprehended by one of ordinary skill in the art with reference to the preceding paragraphs, and would not be further described. 
     Referring to  FIG. 18 , a modification of the first action unit  6  includes the first tubular member  61  that is inserted into the first and second barrels  211 ,  221  (see  FIG. 2 ) and that is co-rotatable with the first barrels  211 , the hydraulic module  62  that is disposed in the first tubular member  61 , the proximal acting member  64  that is co-rotatably mounted in the first tubular member  61 , and the cap member  65  that is mounted to an end of the first tubular member  61 . It should be noted that the distal acting member  63  (see  FIG. 3 ) is omitted. The operation of the modification is similar to that of the first action unit  6  shown in  FIG. 4 , and would not be further described. 
     Referring to  FIGS. 19 and 20 , a fifth embodiment of the hinge according to the disclosure is similar to the first embodiment, and includes the leaf unit  2 , the axle unit  4 , the ring unit  5 , the first action unit  6  and the second action unit  7 . 
     The fixing member  41  has a different configuration such that the fixing member  41  and the second axle  44  are moved into the second barrel  221  of the second leaf  22  via the lower opening of the second barrel  221 . The axle portion  431  of the first axle constituent  43  engages the fixing hole  411  of the fixing member  41  and the fixing hole  440  of the second axle  44 , so the fixing member  41 , the first axle constituent  43  and the second axle constituent  44  are co-rotatable. The protrusions  442  (only one is visible in  FIG. 19 ) of the second axle constituent  44  are in frictional contact with the friction surface  732  of the friction member  73  of the second action unit  7 . 
     Referring to  FIGS. 21 and 22 , a sixth embodiment of the hinge according to the disclosure is similar to the second embodiment, and includes the leaf unit  2 , the axle unit  4 , the ring unit  5 , and the torsional action units  3 . 
     The fixing member  41  has a different configuration, and is moved into the second barrel  221  of the second leaf  22  via the lower opening of the second barrel  221 . The axle portions  421  of the torsional axles  42  respectively and co-rotatably engage the fixing hole  411  and the fixing recess  412  of the fixing member  41  (see  FIG. 22 ). The breaches  422  of the torsional axles  42  are respectively aligned with the fixing grooves  413  of the fixing member  41 , so that the end portions  322  of the torsion springs  32  of the torsional action units  3  respectively extend through the breaches  422  of the torsional axles  42  to respectively engage the fixing grooves  413  of the fixing member  41 . 
     Referring to  FIGS. 23 and 24 , in some embodiment, each of the spacer assemblies  52  may includes two spacers  521 . The surrounding walls  522  of the spacers  521  of each of the spacer assemblies  52  respectively extend into the second barrel  221  and one of the first barrel  211 , and the flange wall  523  of the spacers  521  of each of the spacer assemblies  52  abut against each other and are disposed between the second barrel  221  and the one of the first barrels  211 . 
     In some embodiment, each of the ring members  51  may be made of Polyoxymethylene (POM) or Polytetrafluoroethylene (PTFE), and serves as a bushing for facilitating relative rotation between the corresponding components. Each of the spacer assemblies  52  may be made of metal, such as aluminum, so as to be wear-resistant. Moreover, the material of the first barrels  211 , the second barrel  221  and the exposed flange wall  523  of the spacers  521  of each of the spacer assemblies  52  may be similar to each other, so the hinge may be visually aesthetic. 
     Referring to  FIG. 25 , a modification of the torsional action unit  3  further includes an auxiliary spring  36  and a slide block  37 . 
     The torsional axle  42  further has a rectangular auxiliary axle portion  424  that is opposite to the axle portion  421 . 
     The adjusting member  33  further has an inclined surface  335  that is opposite to the hexagonal adjusting hole  331 . 
     The auxiliary spring  36  is sleeved on the torsional axle  42 , and is surrounded by the torsion spring  32 . 
     The slide block  37  abuts against an end of the auxiliary spring  36 , and has a rectangular hole  371  that is engaged with the auxiliary axle portion  424  of the torsional axle  42 , and an inclined surface  372  that is opposite to the auxiliary spring  36  and that is in slidable contact with the inclined surface  335  of the adjusting member  33 . The slide block  37  is co-rotatable with the torsional axle  42 , and is movable along the auxiliary axle portion  424  of the torsional axle  42  along the axis (X). 
     Referring to  FIGS. 26 and 27 , when the first and second leaves  21 ,  22  are rotated relative to each other by an external force, the torsional axle  42  and the slide block  37  are rotated relative to each other, so that the inclined surface  335  of the adjusting member  33  pushes the inclined surface  372  of the slide block  37  to move the slide block  37  away from the adjusting member  33  along the axis (X) to compress the auxiliary spring  36  so as to generate a restoring force. When the external force is removed, the torsion spring  32  and the auxiliary spring  36  restore to rotate the first and second leaves  21 ,  22  relative to each other, and to move the slide block  37  toward the adjusting member  33  along the axis (X). 
     In summary, the advantages of the disclosure are as follows: 
     1. The torsional axle  42 , the first axle constituent  43  or the second axle constituent  44  can be easily and co-rotatably mounted to the second barrel  221  of the second leaf  22  by virtue of the fixing member  41  that is removably mounted in the second barrel  221  without forming mounting structures on the inner surrounding surface of the second barrel  221 . Moreover, a worn fixing member  41  can be easily substituted with a new fixing member  41 . 
     2. Each of the ring members  51  and the spacer assemblies  52  serves as a bushing for facilitating relative rotation between the corresponding components. 
     3. The configuration of the torsion spring  32  enables the torsion spring  32  to generate a greater restoring force. 
     4. Each of the second and the subsequent embodiments is suitable for use on the occasion that a gap between the first and second objects  11 ,  12  (with reference to  FIG. 1 ) is equal to or slightly greater than the thickness of the first leaf  21  since the second leaf  22  is disposed in the receiving space defined by the U-shaped first leaf  21 . 
     5. During installation of the hinge onto the first and second objects  11 ,  12 , the first leaf  21  can be quickly and accurately positioned relative to the first object  11  by moving the first positioning surface  213  to abut against the edge  111  of the first object  11 , and the second leaf  22  can be quickly and accurately positioned relative to the second object  12  by moving the second positioning surface  223  to abut against the edge  121  of the second object  12 . Therefore, the first and second objects  11 ,  12  are accurately positioned relative to each other, and can be smoothly rotated relative to each other. 
     In the description above, for the purposes of explanation, numerous specific details have been set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art, that one or more other embodiments may be practiced without some of these specific details. It should also be appreciated that reference throughout this specification to “one embodiment,” “an embodiment,” an embodiment with an indication of an ordinal number and so forth means that a particular feature, structure, or characteristic may be included in the practice of the disclosure. It should be further appreciated that in the description, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of various inventive aspects, and that one or more features or specific details from one embodiment may be practiced together with one or more features or specific details from another embodiment, where appropriate, in the practice of the disclosure. 
     While the disclosure has been described in connection with what are considered the exemplary embodiments, it is understood that this disclosure is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.