Abstract:
A computer having a base and a display. The display is pivotable relative to the base. The computer has a securing mechanism that pivotably secures the display to the base. The securing mechanism produces a force that opposes pivotal motion of the display. The securing mechanism also has a clutch operator that is operable to prevent the force from opposing the pivotal motion of the display.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of application Ser. No. 09/837,183 filed on Apr. 18, 2001 now U.S. Pat. No. 6,741,456, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to computer systems. More specifically, the present invention relates to a system and method for pivotably securing a display to a base of a computer system. 
     BACKGROUND OF THE INVENTION 
     The typical notebook computer has a base that houses most of the electronics and a display enclosure that houses a display. The base is typically placed on a flat surface to operate the notebook computer. The base and display enclosure are hinged so that the display can be pivoted relative to the base to a desired viewing position. To stow the computer, the display is pivoted so that the display enclosure and base are folded against one another to protect the display during movement of the computer. One or more latches are used to hold the display and base in the stowed position. A two-step process typically is followed to place the computer in operation from the stowed position. First, the latches are operated to enable the display enclosure to be pivoted and, second, the display is pivoted to a desired position. Latch mechanisms, however, tend to be small features that protrude from the display enclosure. Consequently, they can be easily damaged due to handling. 
     Additionally, the display enclosure hinges often incorporate friction clutches that require significant force applied by the user to pivot the display enclosure. The friction holds the display enclosure in the desired angular position during operation. As the display panels have become increasingly larger, the amount of force required to maintain a display in a desired position has increased. Depending on the weight and size of the base, the user may need to hold the base down with one hand while pivoting the display enclosure with the other hand to ensure the base is not lifted from the surface on which it is resting. 
     Therefore, a need exists for a simpler technique for securing a pivotable display to a base. Specifically, a need exists for a technique that securely maintains a pivotable display in a desired angular position while also enabling the display to be pivoted easily when desired. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a computer having a base and a display is featured. The display is pivotable relative to the base over a range of motion. The computer has a securing mechanism that pivotably secures the display to the base. The securing mechanism utilizes a portion that produces an opposing force to pivotal motion of the display throughout a range of motion. The securing mechanism also has a device operable to prevent the assembly from opposing pivotal motion of the display housing. 
     According to another aspect of the present invention, an assembly for pivotably securing a computer display to a computer base unit is featured. The assembly has a hinge mechanism to enable the computer display to pivot relative to the computer base unit. The assembly also has an opposition member that produces a force to oppose pivotal motion of the display. Also, a clutch is operable to prevent the opposition member from opposing pivotal motion of the display. 
     According to another aspect of the present invention, a method of operating a computer system is featured. The computer system has a base unit, a pivotable display, and a device that produces a frictional force to oppose pivotable motion of the display. The method comprises operating a clutch assembly to reduce the frictional force opposing pivotable motion of the display. The method also comprises pivoting the display to a desired position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and: 
         FIG. 1  is a block diagram of a computer system, according to an exemplary embodiment of the present invention; 
         FIG. 2  is a front perspective view of a notebook computer, according to an exemplary embodiment of the present invention; 
         FIG. 3  is a rear view of the notebook computer of  FIG. 2 ; 
         FIG. 4  is a cross-sectional view, taken generally along line  4 — 4  of  FIG. 3 , illustrating an electrically operated clutch for a hinge assembly operating in a high-friction mode; 
         FIG. 5  is a cross-sectional view, taken along line  4 — 4  of  FIG. 3 , illustrating an electrically operated clutch for a hinge assembly operating in a low-friction mode; 
         FIG. 6  is a cross-sectional view of a mechanically operated clutch for a hinge assembly operating in a high-friction mode; and 
         FIG. 7  is a cross-sectional view of a mechanically operated clutch for a hinge assembly operating in a low-friction mode. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Referring generally to  FIG. 1 , a block diagram is illustrated depicting an exemplary computer system, generally designated by the reference numeral  10 . The computer system  10  may be any of a variety of different types, such as a notebook computer, a desktop computer, a workstation, etc. 
     Computer system  10  comprises a processor  12  to control the function of the computer. Computers also typically require a power supply  14 . The power supply  14  of, for example, a notebook computer typically uses a rechargeable battery to enable the computer to be portable. Various additional devices are usually coupled to the processor  12 , depending on the desired functions of the device  10 . For instance, a user interface  16  may be coupled to the processor  12  to allow an operator to control some or all of the functions of the computer. Examples of user interfaces include a keyboard, a mouse, or a joystick. A monitor  18  is used to allow an operator to view visual information generated by the computer. A communications port  20  may be coupled to processor  12  to enable the computer  10  to communicate with peripheral devices  22 , such as a modem, a printer, or another computer. 
     Software programming is typically used to control the operation of a processor and this software programming is typically stored in electronic memory. There are several different types of electronic memory available for use in computers. For example, the processor  12  may be coupled to volatile memory  24 . Volatile memory may include dynamic random access memory (DRAM) and/or static random access memory (SRAM). The processor  12  also can be coupled to non-volatile volatile memory  26 . Non-volatile memory  26  may include a read only memory (ROM), such as an EPROM, to be used in conjunction with the volatile memory. Also, the non-volatile memory  26  may comprise a high capacity memory such as a disk or tape drive memory. 
     Referring generally to  FIG. 2 , an exemplary portable computer  28 , e.g., a notebook computer, having a base  30  and a display enclosure  32  is illustrated. The base  30  houses a processor, memory, and other electronic components to enable the computer to operate. Additionally, the base houses a keyboard  34  and a mouse pad  36 . The display enclosure  32  houses a display  38 , such as a flat screen. Display  38  is pivotally secured to base  30  so that the display  38  may be pivoted to a desired angular position relative to base  30 . This enables a user to position display  38  to the optimal position for viewing. 
     Referring generally to  FIG. 3 , the display enclosure  32  is secured to the base  30  by two hinge assemblies  40 . Each hinge assembly  40  has a first member  42 , a second member  44 , and a clutch assembly  46 . The first member  42  is secured to the display enclosure  32  and the second member  44  is secured to the base  30 . In this embodiment, threaded fasteners  48  are used to secure the first and second members to the display enclosure  32  and base  30 , respectively. However, other techniques for securing the first and second members to the disclosure  32  and base  30 , respectively, may be utilized. 
     Each hinge assembly  40  is configured so the first member  42  is pivotally secured to the second member  44 , enabling the display  38  to pivot relative to the base  30 . The clutch assembly  46  controls the amount of friction that is produced between the first and second member during pivotal movement of the display  38 . Friction between the first and second members is used to hold the display  38  at a desired angular position relative to the base  30 . 
     Referring again to  FIG. 2 , the hinge assemblies  40  have a high-friction mode of operation and a low-friction mode of operation. In the high-friction mode, the friction between the first member  42  and the second member  44  maintains the display enclosure  32  securely positioned at any angular position relative to base  30 . In the exemplary embodiment, the high-friction mode is the normal mode of operation of the hinge assemblies  40 . The low-friction mode is initiated to facilitate repositioning of the display enclosure  32  relative to the base  30 . 
     In the illustrated embodiment, the low-friction mode is initiated by actuating a clutch operator  50  located on the display enclosure  32 . The clutch operator  50  may be a sliding switch, a push button, etc., that is coupled to the clutch assembly  46 . When clutch operator  50  is actuated, the clutch assembly  46  reduces the friction between the first member  42  and the second member  44  enabling the display  38  to be repositioned more easily. 
     The two modes of operation provide an additional benefit in that the friction between base  30  and display enclosure  32  can be made greater than would normally be feasible. The higher friction enables the display enclosure  32  to be more securely maintained in a desired position. Normally, high friction between display enclosure  32  and base  30  makes it difficult for the display enclosure  32  to be repositioned, or at least be repositioned easily. However, because the hinge assembly can be placed in a low-friction mode during repositioning, higher friction between the base  30  and display enclosure  32  can be utilized. 
     Referring generally to  FIG. 4 , a cross-sectional view of one exemplary hinge assembly  40  is illustrated. In the illustrated embodiment, an electromagnetic coil  52  is used to operate the clutch assembly  46 . A first threaded fastener  54  and a second threaded fastener  56  secure the coil  52  to second member  44 . Electricity is supplied to coil  52  by electrical wiring  58  extending from inside the base  30 . The wiring may be routed to coil  52  in a variety of ways, such as through hinge assembly  40 . 
     In the illustrated embodiment, a portion  60  of the second member forms an axle to enable the first member  42  to rotate about the second member  44 . Additionally, in the illustrated embodiment, a beveled washer  62  is disposed between a flanged portion  64  of the first threaded fastener  54  and a generally flat washer  66  is disposed between the beveled washer  62  and the first member  42 . 
     The hinge assembly  40  is configured so that the beveled washer  62  normally applies a force to drive the flat washer  66  against the first member  42  and, subsequently, to drive the first member  42  against the second member  44 . The force of the first member  42  abutting against the second member produces friction between the inner surface  68  of the first member  42  and the outer surface  70  of the second member  44  during the high-friction mode of operation. The force of the beveled washer  62  also produces a gap  72  between the flat washer  66  and the coil  52  during the high-friction mode of operation. 
     In this embodiment, the flat washer  66  is comprised of a metallic material. When clutch operator  50  is activated, electric power is applied to coil  52 . A magnetic field is produced by coil  52  that attracts the flat washer  66  towards coil  52  as illustrated in FIG.  5 . The attractive force produced by the coil  52  is greater than the force produced by the beveled washer  62 , driving the flat washer  66  towards coil  52 , as represented by the arrows  74 . The flat washer  66  closes the gap  72  between flat washer  66  and coil  52 , compressing the beveled washer  62  and producing a gap  76  between the flat washer  66  and the first member  42 . Consequently, the force driving first member  42  against second member  44  is removed. 
     When the movement of flat washer  66  produces a gap  78  between the first member  42  and the second member  44 , there is no friction produced between the inner portion  68  of first member  42  and outer portion  70  of second member  44  during movement of display  38 . However, even if the inner and outer portions remain in contact, the frictional force produced between the first and second members is reduced when the force of the beveled washer  62  acting on the first member  42  is removed, making pivotal movement of display  38  easier. 
     By way of example, the first member  42  and second member  44  are comprised of a light-weight plastic material. Alternatively, a portion of the first member  42  may be comprised of a metallic material so that the magnetic field generated by coil  52  pulls the first member  42  away from the second member  44  to produce gap  78  between the first and second members. Alternatively, the flat washer  66  may be secured to the first member  42  so that the first member  42  is moved with the flat washer  66 . 
     Referring generally to  FIG. 6 , clutch assembly  46  also may be mechanically operated. In the illustrated embodiment, hinge assembly  40  has a threaded member  80 , a movable member  82 , and a spring  84 . The threaded member  80  is affixed to the second member  44 . Threaded member  80  also has a hollow interior  86  to house a cylindrical portion  88  of the movable member  82 . The moveable member  82  also has a flanged portion  90 . 
     Spring  84  is secured to fixed member  80  and movable member  82  and applies a force to pull flanged portion  90  against first member  42 , forcing first member  42  against second member  44  and producing friction between first member  42  and second member  44 . In the illustrated embodiment, the clutch operator  50  is mechanically coupled to a cam  92 . When the clutch operator is activated, it causes the cam  92  to rotate. As the cam  92  is rotated, the cam  92  drives the movable member  82  linearly. In this view, cam  92  is illustrated in the high-friction mode. The cam is oriented in a first orientation  94  in the high-friction mode. 
     Referring generally to  FIG. 7 , when operator  50  is actuated, cam  92  is rotated to a second orientation  96 , driving the surface of cam  92  against the cylindrical portion  88  of movable member  82 . The force applied by cam  92  drives movable member  82  linearly to the left in this view, as illustrated by the arrows  98 , producing a gap  100  between the flanged portion  90  and first member  42  and reducing the friction between first member  42  and second member  44 . A gap  102  may be produced between first member  42  and second member  44 . However, regardless of whether a gap  102  is produced between first member  42  and second member  44 , friction is reduced between first member  42  and second member  44 . 
     It will be understood that the foregoing description is of preferred embodiments of this invention, and that the invention is not limited to the specific forms shown. For example, a spring may be utilized rather than a beveled washer in an electrically operated clutch. These and other modifications may be made in the design and arrangement of the elements without departing from the scope of the invention as expressed in the appended claims.