Abstract:
A position-limit hinge includes an axle housing, a first hinge shaft, a second hinge shaft, a first position-limit device set and a second position-limit device set. By means of enabling the first position-limit device set and the second position-limit device set to be alternatively changed between a position-limit status and a freely rotatable status, the first hinge shaft is driven to rotate or the axle housing is driven to turn about the second hinge shaft, enabling a cover member of an electronic device carrying the position-limit hinge to be smoothly opened relative to a base member.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to hinge technology and more particularly, to a position-limit hinge for use in a dual-leaf electronic device, which allows the cover member of the dual leaf electronic device to be turned from the top side of the base member to the bottom side thereof. 
     2. Description of the Related Art 
     A dual-leaf electronic device such as notebook computer, smart phone, etc. generally comprises a base member and a cover member, wherein the cover member of the electronic device can be turned from the top side of the base member to the bottom side thereof, enabling the electronic device to be used as a tablet computer. A dual-leaf electronic device uses a dual-shaft hinge for enabling the cover member thereof to be turned through 360°. When opening the cover member of the dual-leaf electronic device through 360°, the first hinge shaft is rotated through 180° and then the second hinge shaft is rotated through another 180°. However, when turned the cover member through 180°, the cover member and the base member are not kept on a plane, leading to the destruction of the sense of beauty. A link can be used for enabling the first hinge shaft and the second hinge shaft to be rotated synchronously so that when the cover member is turned through 180°, the cover member and the base member can be kept on a plane. However, the use of the link can produce an idle stroke, i.e., the first hinge shaft and the second hinge shaft cannot be accurately synchronously rotated for enabling the cover member to be turned smoothly. Further, for use in an electronic device having light, thin, short and small characteristics, the size of the hinge must be relatively reduced. However, reducing the size of the hinge will relatively reduce the strength of the link, and the link can easily be forced to break by an external force. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide a position-limit hinge, which uses a first position-limit device set and a second position-limit device set to let a first hinge shaft to be rotated or an axle housing to be turned about a second hinge shaft, enabling a cover member of an electronic device carrying the position-limit hinge to be smoothly opened relative to a base member. 
     To achieve this and other objects of the present invention, a position-limit hinge of the invention comprises an axle housing, a first hinge shaft, a second hinge shaft, a first position-limit device set and a second position-limit device set. The axle housing comprises a first axle hole and a second axle hole. 
     The first hinge shaft comprises a first shaft portion located at one end thereof and rotatably inserted into the first axle hole of the axle housing, a first mounting portion located at an opposite end thereof outside the axle housing and fixedly fastened to a cover member of an electronic device, and a first position-limit portion spaced between the first shaft portion and the first mounting portion and exposed to the outside of the axle housing. The second hinge shaft comprises a second shaft portion located at one end thereof and rotatably inserted into the second axle hole of the axle housing, a second mounting portion located at an opposite end thereof and fixedly fastened to a base member of the electronic device outside the axle housing, and a second position-limit portion spaced between the second shaft portion and the second mounting portion and exposed to the outside of the axle housing. 
     The first position-limit device set comprises a first cam wheel, a second cam wheel, and a first position-limit member. The first cam wheel comprises a first mounting hole fastened to the first position-limit portion of the first hinge shaft, and a first actuation barrel surrounding the first mounting hole. The second cam wheel comprises a second mounting hole fastened to the second position-limit portion of the second hinge shaft, and a second actuation barrel surrounding the second mounting hole. The first position-limit member is disposed between the first cam wheel and the second cam wheel, having opposing top and bottom sides thereof respectively stopped at the first actuation barrel and the second actuation barrel. 
     The second position-limit device set comprises a third cam wheel, a fourth cam wheel, and a second position-limit member. The third cam wheel comprises a third mounting hole fastened to the first position-limit portion of the first hinge shaft, and a third actuation barrel surrounding the third mounting hole. The fourth cam wheel comprises a fourth mounting hole fastened to the second position-limit portion of the second hinge shaft, and a fourth actuation barrel surrounding the fourth mounting hole. The second position-limit member is disposed between the third cam wheel and the fourth cam wheel, having opposing top and bottom sides thereof respectively stopped at the third actuation barrel and the fourth actuation barrel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of a position-limit hinge in accordance with a first embodiment of the present invention. 
         FIG. 2  is an exploded view of the position-limit hinge in accordance with the first embodiment of the present invention. 
         FIG. 3  is a front view of the position-limit hinge in accordance with the first embodiment of the present invention. 
         FIG. 4  is a sectional view taken along line A-A of  FIG. 1 . 
         FIG. 5  is a sectional view taken along line B-B of  FIG. 1 . 
         FIG. 6  is a front view of the first position-limit device set and second position-limit device set of the position-limit hinge in accordance with the first embodiment of the present invention. 
         FIG. 7  is a sectional view taken along line C-C of  FIG. 6 . 
         FIG. 8  is a sectional view taken along line D-D of  FIG. 6 . 
         FIG. 9  is a schematic elevational view of the first embodiment of the present invention, illustrating an operation status of the position-limit hinge. 
         FIG. 10  is a schematic front view of the first embodiment of the present invention, illustrating an operation status of the position-limit hinge. 
         FIG. 11  is a sectional view taken along line E-E of  FIG. 9 . 
         FIG. 12  is a sectional view taken along line F-F of  FIG. 9 . 
         FIG. 13  is a schematic elevational view of the first embodiment of the present invention, illustrating another operation status of the position-limit hinge. 
         FIG. 14  is a schematic front view of the first embodiment of the present invention, illustrating another operation status of the position-limit hinge. 
         FIG. 15  is a sectional view taken along line G-G of  FIG. 13 . 
         FIG. 16  is a sectional view taken along line H-H of  FIG. 13 . 
         FIG. 17  is a schematic drawing of the first embodiment of the present invention, illustrating the operation of the position-limit hinge with the movement of the cover member of the electronic device from the top side of the base member to the bottom side thereof. 
         FIG. 18  is an elevational view of a position-limit hinge in accordance with a second embodiment of the present invention. 
         FIG. 19  is a front view of the position-limit hinge in accordance with the second embodiment of the present invention. 
         FIG. 20  is a sectional view taken along line I-I of  FIG. 18 . 
         FIG. 21  is a sectional view taken along line J-J of  FIG. 18 . 
         FIG. 22  is an enlarged view of Part K of  FIG. 20 . 
         FIG. 23  is a schematic elevational operational view of the position-limit hinge in accordance with the second embodiment of the present invention. 
         FIG. 24  is a schematic front operational view of the position-limit hinge in accordance with the second embodiment of the present invention. 
         FIG. 25  is a sectional view taken along line L-L of  FIG. 23 . 
         FIG. 26  is a sectional view taken along line M-M of  FIG. 23 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1-8 , a position-limit hinge in accordance with a first embodiment of the present invention is shown. The position-limit hinge comprises an axle housing  1 , a first hinge shaft  2 , a second hinge shaft  3 , a first position-limit device set  4  a second position-limit device set  5 , and a positioning member  6 . 
     The axle housing  1  defines therein a first axle hole  11  and a second axle hole  12 . 
     The first hinge shaft  2  comprises a first shaft portion  21  located at one end thereof and rotatably inserted into the first axle hole  11  of the axle housing  1 , a first mounting portion  22  located at an opposite end thereof and fixedly fastened to a cover member  71  of an electronic device  7  and exposed to the outside of the axle housing  1 , a first position-limit portion  23  connected between the first shaft portion  21  and the first mounting portion  22  and exposed to the outside of the axle housing  1 , and a first stop flange  24  extending around the periphery thereof between the first mounting portion  22  and the first position-limit portion  23 . 
     The second hinge shaft  3  comprises a second shaft portion  31  located at one end thereof and rotatably inserted into the second axle hole  12  of the axle housing  1 , a second mounting portion  32  located at an opposite end thereof and fixedly fastened to a base member  72  of the electronic device  7  and exposed to the outside of the axle housing  1 , a second position-limit portion  33  connected between the second shaft portion  31  and the second mounting portion  32  and exposed to the outside of the axle housing  1 , and a second stop flange  34  extending around the periphery thereof between the second mounting portion  32  and the second position-limit portion  33 . 
     The first position-limit device set  4  comprises a first cam wheel  41 , a second cam wheel  42 , a first position-limit member  43  and a first locating plate  44 . The first locating plate  44  comprises a first pivot hole  441  located at one end thereof and pivotally coupled to the first position-limit portion  23  of the first hinge shaft  2 , a second pivot hole  442  located at an opposite end thereof and pivotally coupled to the second position-limit portion  33  of the second hinge shaft  3 , a first sliding slot  443  spaced between the first pivot hole  441  and the second pivot hole  442 , and two first position-limit portions  444  disposed in the first sliding slot  443  at two opposite lateral sides. The first cam wheel  41  and the second cam wheel  42  are disposed at one same side relative to the first locating plate  44 . The first cam wheel  41  comprises a first mounting hole  411  fastened to the first position-limit portion  23  of the first hinge shaft  2 , a first actuation barrel  412  surrounding the first mounting hole  411 , a first upper limit position  413  located at one end of the first actuation barrel  412  near the second hinge shaft  3  and a first lower limit position  414  located at an opposite end of the first actuation barrel  412 . The second cam wheel  42  comprises a second mounting hole  421  fastened to the second position-limit portion  33  of the second hinge shaft  3 , a second actuation barrel  422  surrounding the second mounting hole  421 , a second upper limit position  423  located at one end of the second actuation barrel  422 , and a second lower limit position  424  located at an opposite end of the second actuation barrel  411  near the first hinge shaft  2 . The first position-limit member  43  comprises a first body  431  slidably inserted into the first sliding slot  443  between the first cam wheel  41  and the second cam wheel  42 , and two first stop plates  432  respectively extended from two opposite lateral sides of the first body  431  and slidably supported on the first position-limit portions  444 . Further, the first upper limit position  413  of the first cam wheel  41  and the second lower limit position  424  of the second cam wheel  42  are respectively stopped at opposing top and bottom sides of the first body  431 . 
     The second position-limit device set  5  comprises a third cam wheel  51 , a fourth cam wheel  52 , a second position-limit member  53  and a second locating plate  54 . The second locating plate  54  comprises a third pivot hole  541  located at one end thereof and pivotally coupled to the first position-limit portion  23  of the first hinge shaft  2 , a fourth pivot hole  542  located at an opposite end thereof and pivotally coupled to the second position-limit portion  33  of the second hinge shaft  3 , a second sliding slot  543  spaced between the third pivot hole  541  and the fourth pivot hole  542 , and two second position-limit portions  544  disposed in the second sliding slot  543  at two opposite sides. The third cam wheel  51  and the fourth cam wheel  52  are disposed at one same side relative to the second locating plate  54 . The third cam wheel  51  comprises a third mounting hole  511  fastened to the first position-limit portion  23  of the first hinge shaft  2 , a third actuation barrel  512  surrounding the third mounting hole  511 , a third upper limit position  513  located at one end of the third actuation barrel  512 , and a third lower limit position  514  located at one end of the third actuation barrel  512  near the second hinge shaft  3 . The fourth cam wheel  52  comprises a fourth mounting hole  521  fastened to the second position-limit portion  33  of the second hinge shaft  3 , a fourth actuation barrel  522  surrounding the fourth mounting hole  521 , a fourth upper limit position  523  located at one end of the fourth actuation barrel  522  near the first hinge shaft  2 , and a fourth lower limit position  524  located at an opposite end of the fourth actuation barrel  522 . The second position-limit member  53  comprises a second body  531  slidably inserted into the second sliding slot  543  and disposed between third cam wheel  51  and the fourth cam wheel  52 , and two second stop plates  532  respectively extended from two opposite lateral sides of the second body  531  and slidably supported on the second position-limit portions  544 . Further, the third lower limit position  514  of the third cam wheel  51  and the fourth upper limit position  523  of the fourth cam wheel  52  are respectively stopped at opposing top and bottom sides of the second body  531 . 
     The positioning member  6  is disposed at one side relative to the second position-limit device set  5 , comprising a fifth pivot hole  61  located at one end thereof and pivotally coupled to the first position-limit portion  23  of the first hinge shaft  2 , a sixth pivot hole  62  located at an opposite end thereof and pivotally coupled to the second position-limit portion  33  of the second hinge shaft  3 , a raised position-limit portion  63  spaced between the fifth pivot hole  61  and the sixth pivot hole  62 , a first stop wall  631  and a second stop wall  632  bilaterally located at a top side of the raised position-limit portion  63 , and a third stop wall  633  and a fourth stop wall  634  bilaterally located at an opposing bottom side of the raised position-limit portion  63 . Further, the first stop flange  24  of the first hinge shaft  2  is disposed between the first stop wall  631  and second stop wall  632  of the position-limit portion  63 . The second stop flange  34  of the second hinge shaft  3  is disposed between the third stop wall  633  and fourth stop wall  634  of the position-limit portion  63 . 
     Referring to  FIGS. 1 ,  4 ,  5  and  FIGS. 9-17 , the third lower limit position  514  of the third cam wheel  51  of the second position-limit device set  5  and the fourth upper limit position  523  of the fourth cam wheel  52  are stopped at the second body  531  of the second position-limit member  53 , i.e., the distance between the third lower limit position  514  and the fourth upper limit position  523  is equal to the distance between the top and bottom sides of the second body  531 , as illustrated in  FIGS. 4 and 5 , and therefore, the rotation of the third cam wheel  51  and the rotation of the fourth cam wheel  52  are limited; the first upper limit position  413  of the first cam wheel  41  of the first position-limit device set  4  is stopped at the top side of the first body  431  and the bottom side of the first body  431  is stopped at the second lower limit position  424  of the second cam wheel  42  opposite to the second upper limit position  423 , i.e., the second cam wheel  42  is biased on the second lower limit position  424  in direction away from the second upper limit position  423  through an angle θ, thus, the second cam wheel  42  can be rotated through an angle θ; as illustrated in  FIGS. 9-17 , when the user open the cover member  71  of the electronic device  7 , the third lower limit position  514  and fourth upper limit position  523  of the second position-limit device set  5  are stopped at the second body  531  of the second position-limit member  53 , and the second cam wheel  42  of the first position-limit device set  4  can be biased through an angle θ, therefore, opening the cover member  71  of the electronic device  7  will drive the axle housing  1  to turn about the second hinge shaft  3 , causing the first position-limit member  43  of the first position-limit device set  4  to turn about the second hinge shaft  3 ; when the axle housing  1  is turned to the position where the bottom side of the first position-limit member  43  is stopped at the second lower limit position  424  of the second cam wheel  42 , the first position-limit device set  4  becomes rotatable; during turning of the axle housing  1 , the second position-limit member  53  of the second position-limit device set  5  will be turned about the second hinge shaft  3  in direction from the fourth upper limit position  523  of the fourth cam wheel  52  toward the fourth lower limit position  524 , i.e., the distance between the third actuation barrel  512  and the fourth actuation barrel  522  will be gradually increased, causing the second position-limit device set  5  to be changed from the position-limit status to a freely rotatable status; when the user keeps opening the cover member  71  after the first position-limit device set  4  is stopped from movement, the first hinge shaft  2  will be rotated, driving the first cam wheel  41  to rotate in direction from the first upper limit position  413  toward the first lower limit position  414 ; because the first cam wheel  41  is rotated in direction from the first upper limit position  413  toward the first lower limit position  414  at this time, the distance between the first actuation barrel  412  and the second actuation barrel  422  will be gradually increased to become larger than the distance between the opposing top and bottom sides of the first body  431 , causing the first position-limit device set  4  to be changed from the position-limit status to a freely rotatable status; further, during rotation of the first hinge shaft  2 , the third cam wheel  51  of the second position-limit device set  5  will be rotated in the same rotating direction of the first hinge shaft  2 ; at this time, the third cam wheel  51  is rotated in direction from the third lower limit position  514  toward the third upper limit position  513 , therefore, the distance between the third actuation barrel  512  and the fourth actuation barrel  522  will be gradually increased at this time, causing the third lower limit position  514  of the third cam wheel  51  and the fourth upper limit position  523  of the fourth cam wheel  52  to be respectively stopped at the opposing top and bottom sides of the second body  531 ; as soon as the third lower limit position  514  and the fourth upper limit position  523  are respectively stopped at the opposing top and bottom sides of the second body  531 , the second position-limit device set  5  is stopped from movement, prohibiting the second hinge shaft  2  from rotation; as illustrated in  FIG. 17 , repeating the aforesaid procedure enables the cover member  71  to be turned to the bottom side of the base member  72 . 
     Referring to  FIGS. 18-26 , in a second embodiment of the present invention, the distance between the third lower limit position  914  of the third cam wheel  91  of the second position-limit device set  9  and the fourth upper limit position  923  of the fourth cam wheel  92  at the initial point is larger than the distance between the opposing top and bottom sides of the second body  931 , therefore a gap exists between the third cam wheel  91  and the second body  931 , allowing the second position-limit device set  9  to be freely rotated; the distance between the first upper limit position  813  of the first cam wheel  81  of the first position-limit device set  8  and the second lower limit position  824  of the second cam wheel  82  at the initial point is equal to the distance between the opposing top and bottom sides of the first body  831 , therefore the first upper limit position  813  and the second lower limit position  824  are respectively stopped at the opposing top and bottom sides of the first body  831 , and thus, rotation of the first position-limit device set  8  is limited; when the user opens the cover member  71  of the electronic device  7 , the first upper limit position  813  and second lower limit position  824  of the first position-limit device set  8  are respectively stopped at the opposing top and bottom sides of the first body  831 , the first cam wheel  81  can simply be rotated in direction from the first upper limit position  813  toward the first lower limit position  814 , thus, opening the cover member  71  of the electronic device  7  drives the first hinge shaft  2  to rotate in direction from the first upper limit position  813  toward the first lower limit position  814 ; because the first cam wheel  81  is rotated in direction from the first upper limit position  813  toward the first lower limit position  814  at this time, the distance between the first actuation barrel  812  and the second actuation barrel  822  is gradually increased to become larger than the distance between the opposing top and bottom sides of the first body  831 , causing the first position-limit device set  8  to be changed from the position-limit status to a freely rotatable status; during rotation of the first hinge shaft  2 , the third cam wheel  91  of the second position-limit device set  9  is rotated in the same rotating direction of the first hinge shaft  2 , at this time, the third cam wheel  51  is rotated in direction from the third lower limit position  914  toward the third upper limit position  913 , therefore, the distance between the third actuation barrel  912  and the fourth actuation barrel  922  is gradually reduced, causing the third lower limit position  914  of the third cam wheel  91  and the fourth upper limit position  923  of the fourth cam wheel  92  to be respectively stopped at the opposing top and bottom sides of the second body  931 ; as soon as the third lower limit position  914  and the fourth upper limit position  923  are respectively stopped at the opposing top and bottom sides of the second body  931 , the second position-limit device set  9  is stopped from movement, prohibiting the second hinge shaft  2  from rotation; thus, when the user keeps opening the cover member  71 , the axle housing  1  will be turned about the second hinge shaft  3 , driving the second position-limit member  93  of the second position-limit device set  9  to turn about the second hinge shaft  3  in direction from the fourth upper limit position  923  of the fourth cam wheel  92  toward the fourth lower limit position  924 , and thus, the distance between the third actuation barrel  912  and the fourth actuation barrel  922  will be gradually increased, causing the second position-limit device set  9  to be changed from the position-limit status to a freely rotatable status; when turning the axle housing  1  about the second hinge shaft  3 , the first position-limit member  83  of the first position-limit device set  8  is moved in direction from the second lower limit position  824  of the second cam wheel  82  toward the second upper limit position  823 , and therefore the distance between the first actuation barrel  812  and the second actuation barrel  822  will be gradually reduced, causing the first upper limit position  813  and the second lower limit position  824  to be respectively stopped at the opposing top and bottom sides of the first body  831 ; at this time, the first position-limit device set  8  is stopped from movement, prohibiting the axle housing  1  from movement; when the user keeps opening the cover member  71  after the first position-limit device set  8  is stopped from movement, the first hinge shaft  2  will be rotated, causing the second position-limit device set  9  to be changed from the freely rotatable status to a position-limit status and the first position-limit device set  8  to be changed from the position-limit status to a freely rotatable status; repeating the aforesaid procedure causes the cover member  71  to be turned to the bottom side of the base member  72 . 
     Therefore, the technical features of the present invention that eliminate the drawbacks of the prior art designs are as follows: 
     (1) The invention enables the first position-limit device set  4  and the second position-limit device set  5  to be alternatively changed between a position-limit status and a freely rotatable status, so that only the first hinge shaft  2  is rotated or the axle housing  1  is turned about the second hinge shaft  3  at a specific time, facilitating accurate control of the range and order of rotation; thus, when turning the cover member  71  through 180°, the cover member  71  and the base member  72  can be kept in horizontal; the cover member  71  can be closed on the base member  72 , or opened and attached to the bottom side of the base member  72 . 
     (2) The invention enables the first cam wheel  41 , the second cam wheel  42 , the third cam wheel  51  and the fourth cam wheel  52  to be alternatively stopped and rotated to bear external force, preventing breaking or component damage.