Patent Publication Number: US-7712188-B2

Title: Hinge for portable computer

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a hinge for a portable computer, and in particular relates to a hinge for a portable computer requiring less torque to open and greater torque to close. 
     2. Description of the Related Art 
     Referring to  FIG. 1 , a portable computer has a monitor  32  and a base  31  connected by a hinge (not shown). The hinge allows the monitor  32  to rotate with respect to the base  31 . Currently, the torque required for operating a hinge of a portable computer is constant. Operation of a conventional hinge is described via a torque curve in the following: 
       FIG. 2  depicts a torque curve of a hinge for a portable computer, wherein the hinge does not maintain the monitor in a closed position. Rather, the monitor is locked in the closed position via a latch (not shown). To open the monitor, the latch must be released. As shown in  FIG. 2 , the required torque T is a constant A 1  as the monitor is opened (θ=0°−180°) and a constant “A” as the monitor is closed (θ=180°−0°), wherein A 1 =0.7A−0.75A. 
       FIG. 3  depicts a torque curve of another hinge for a portable computer, wherein the hinge is capable of maintaining the monitor in a closed position. In this case, no latch is provided for locking the monitor in the closed position. It is noted that the torque is not zero at θ=0° for the hinge to position the monitor. Furthermore, the required torque T remains constant through most of the process of operation. Specifically, the required torque T is a constant A 1  during opening of the monitor (θ=15°−180°) and a constant “A” during closing of the monitor (θ=180°−15°). In  FIG. 3 , A 0 =1.2A. 
     Different designs may have different structural specifications for hinges, although the performance of hinges in portable computers is similar. Thus, only the torque curves of the hinges have been described and structural descriptions of the hinges have been omitted. 
     To meet design requirements, the battery in a typical portable computer is generally disposed at the rear of the base and near the hinge. The battery is a heavy element in the portable computer. Such an arrangement concentrates the weight of the portable computer at the rear. As a possible result, the base is raised when the monitor is opened. Alternatively, after the monitor is rotated to an angle, the base may accidentally fall and collide with a table or be raised along with rotation of the monitor. Thus, the monitor must be opened with both hands. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the invention is to provide a hinge for a portable computer preventing the described problems. The hinge requires less torque for opening, and greater torque for closing the monitor. The torque required for operating the hinge of the invention depends on the position of the monitor. 
     An exemplary embodiment of the portable computer includes a monitor, a base, and a hinge. The hinge includes a shaft sleeve, a rotary shaft, a driven element, and a resistance structure. The shaft sleeve is fixed to the base. The rotary shaft is fixed to the monitor and disposed in the shaft sleeve. The driven element is connected to and driven by the rotary shaft. The resistance structure is disposed adjacent to the driven element, wherein the driven element does not contact the resistance structure when the rotary shaft is rotated in the shaft sleeve within a first angular range, and the driven element contacts the resistance structure and sustains a resistance when the rotary shaft is rotated in the shaft sleeve within a second angular range. 
     Because the resistance depends on the rotational angle of the monitor, the torque required for operating the hinge depends on the position of the monitor. The torque required for opening the monitor is less than that for closing it. Thus, the monitor can be opened with one hand and the base of the portable computer is prevented from accidentally impacting another surface. The invention may provide more convenient operation and prevent accidental collision in operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  is a schematic diagram of a portable computer; 
         FIG. 2  depicts a torque curve of a hinge for a portable computer; 
         FIG. 3  depicts a torque curve of another hinge for a portable computer; 
         FIG. 4  depicts a torque curve of a hinge in accordance with the invention; 
         FIG. 5  depicts a torque curve of another hinge in accordance with the invention; 
         FIG. 6  is a schematic diagram of a hinge in accordance with a first embodiment of the invention; 
         FIG. 7  is an exploded view of the hinge of  FIG. 6 ; 
         FIG. 8  is a schematic diagram of a hinge in accordance with a second embodiment of the invention; and 
         FIG. 9  is an exploded view showing the driven element and the rotary shaft of the hinge in accordance with the second embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
     To smoothly rotate the monitor, the torque required for operating the hinge of the invention depends on the position of the monitor. In the following descriptions, the torque curve of the hinge prior to the structure of the hinge is introduced. 
       FIG. 4  depicts a torque curve of a hinge of the invention, wherein the hinge does not have a function for maintaining the monitor in the closed position. As the monitor is opened, the required torque T is a constant “A 1 ” in the angular range of θ=120°−180°, and increases to a constant “A” in the angular range of θ=120°−180°. That is, the initial required torque is small, and then increases. Thus, if the user releases the monitor in the angular range of η=120°−180°, rotation of the monitor in the opened direction due to gravity will be prevented. During the process of closing the monitor, the required torque T is a constant “A” in the angular range of θ=180°−120°, preventing rotation of the monitor in the opened direction due to gravity, and reduces to a constant A 2  in the angular range of θ=120°−0°, wherein A 2 =0.9A. It is noted that the torque A 2 (=0.9A) required for closing the monitor exceeds that required for opening the monitor A 1 (=0.7A−0.75A). Thus, opening the monitor requires more effort than closing it. Such a design prevents the monitor from continuing to rotate in the angular range of θ=60°−0° in the closed direction due to gravity. 
       FIG. 5  depicts a torque curve of another hinge of the invention, wherein the hinge is capable of maintaining the monitor in the closed position. Thus, the required torque for operating the hinge is not zero at the angle θ=0°. As shown in  FIG. 5 , the required torque T changes at the angle θ=120°, similar to that shown in  FIG. 4 . Thus, the introduction of the torque curve is omitted. 
     Referring to  FIGS. 6 and 7 ,  FIGS. 6 and 7  are schematic diagrams of a hinge H 1  in accordance with a first embodiment of the invention. The hinge H 1  comprises a shaft sleeve  11  having an end surface  110 , a rotary shaft  12  disposed in the shaft sleeve  11 , a resistance structure  13 , and a driven element  14  connected to and driven by the rotary shaft  12 . The resistance structure  13 , disposed between the shaft sleeve  11  and the driven element  14  to be separably contacted by adjacent to the driven element  14 , comprises a slope portion  131  relatively slanted from the end surface  110  of the shaft sleeve  11  and a flat portion  132  connected to the slope portion  131 . The shaft sleeve  11  is fixed to the base (not shown) of a portable computer through a connecting element  17  which is connected to the flat portion  132  of the resistance structure  13 , while the rotary shaft  12  is fixed to the monitor (not shown) through another connecting element  18 . The rotary shaft  12  is rotated in the shaft sleeve  11  by the monitor when the monitor is rotated with respect to the base. Note that the slope portion  131  of the resistance structure  13  is increasingly and relatively slanted from the end surface  110  of the shaft sleeve  11 . 
     The driven element  14  has a convex part  142  and a through hole  141 . The rotary shaft  12  passes through the through hole  141  of the driven element  14 . The cross section of the rotary shaft  12  is non-circular and matches the shape of the through hole  141  of the driven element  14 . Thus, the rotary shaft  12  is capable of rotating the driven element  14 . 
     The rotary shaft  12  sequentially passes through the shaft sleeve  11 , the driven element  14 , a plurality of gaskets  15 , and a retaining element  16 . The retaining element  16  is fixed to the rotary shaft  12 . The driven element  14  and the gaskets  15  are clamped by the shaft sleeve  11  and the retaining element  16 . 
     The resistance structure  13  protrudes from an end surface  110  of the shaft sleeve  11  and adjacent to the driven element  14 . When the rotary shaft  12  is rotated in the shaft sleeve  11  within a first angular range (e.g. θ=0°−120°), the driven element  14  is rotated by the rotary shaft  12  without contacting the resistance structure  13 . The torque required for operating the hinge is small. When the rotary shaft  12  is rotated in the shaft sleeve  11  within a second angular range (e.g. θ=120°−180°) different from the first angular range, the driven element  14  contacts the resistance structure  13  and sustains a resistance. Thus, the torque required for operating the hinge increases from constant A 1  to constant “A” as shown in  FIGS. 4 and 5 . 
       FIG. 8  is a schematic diagram of a hinge H 2  in accordance with a second embodiment of the invention, wherein the hinge H 2  comprises a shaft sleeve  21 , a rotary shaft  22  disposed in the shaft sleeve  21 , a driven element  24  connected to and driven by the rotary shaft  22  and comprising two end surfaces  2421 , and a torsional spring  23  substantially disposed between the shaft sleeve  21  and the driven element  24 . The shaft sleeve  21  is fixed to the base (not shown) of a portable computer through a connecting element  27 , while the rotary shaft  22  is fixed to the monitor (not shown) through another connecting element  26 . The rotary shaft  22  is rotated in the shaft sleeve  21  by the monitor when the monitor is rotated with respect to the base. The driven element  24  comprises a convex part  242  having two end surfaces  2421  and a through hole  241 . The torsional spring  23  comprises an acting end  231  to be separably contacted by the one of the end surfaces  2421  of the convex part  242  of the driven element  24 . In this embodiment, the resistance structure  23  is constituted by a torsional spring, and one end (not shown in FIGS.) of the torsional spring is fixed to the connecting element  27 . 
     Referring also to  FIG. 9 , the rotary shaft  22  passes through the through hole  241  of the driven element  24 . The cross section of the rotary shaft  22  is non-circular and matches the shape of the through hole  241  of the driven element  24 . Thus, the rotary shaft  22  is capable of rotating the driven element  24 . 
     When the rotary shaft  22  is rotated in the shaft sleeve  21  within a first angular range (e.g. θ=0°−120°), the end surface  2421  of the driven element  24  is rotated by the rotary shaft  22  without contacting the acting end  231  of the resistance structure  23 . The torque required for operating the hinge is small. When the rotary shaft  22  is rotated in the shaft sleeve  21  with a second angular range (e.g. θ=120°−180°), the end surface  2421  of the driven element  24  contacts the acting end  231  of the resistance structure  23  and sustains a resistance. Thus, the torque required for operating the hinge increases from constant A 1  to constant “A” as shown in  FIGS. 4 and 5 . 
     In the invention, the torque required for operating the hinge depends on the position of the monitor. The torque required for opening the monitor is less than that for closing it. Thus, the monitor can be opened with one hand and the base of the portable computer is prevented from accidentally impacting another surface. The invention may provide more convenient operation and prevent accidental collision in operation. 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.