PATENT DOCUMENT

Publication Number: US-8132293-B2
Application Number: US-33552008-A
Country: US
Kind Code: B2

Title: Portable computer clutch structures

Abstract:
A portable computer is provided that has a housing. Upper and lower portions of the housing may be joined using a hinge. A clutch mechanism may be associated with the hinge. The clutch mechanism may exhibit asymmetrical friction during opening and closing of the portable computer housing portions. Additional closing force may help to prevent the computer from having a lid that is too easy to close, without overwhelming the clutch with unnecessary friction. The clutch may have a clutch spring that is attached to a clutch shaft using a slot in the shaft. A lobe may be provided in the spring in the vicinity of the slot. A protective cap may be provided over the tip of the shaft to prevent damage to nearby wires. A friction band in the clutch may be used to directly engage an end of the spring.

Claims:
What is claimed is: 
     
       1. Hinge clutch structures for a portable computer hinge that connects first and second housing portions in a portable computer, comprising:
 a base mount structure having an associated shaft with a longitudinal axis; 
 a friction band structure that rotates relative to the shaft about the longitudinal axis and that has a first friction band and a second friction band, wherein the first and second friction bands are wrapped around the shaft in opposing directions, wherein the first and second friction bands have respective first and second widths along the shaft, and wherein the first and second widths are different; and 
 a clutch spring disposed in a spiral around the shaft, wherein the shaft comprises an end having a slot, wherein the spring is attached to the shaft at the slot, and wherein the spring has a stress relief lobe adjacent to the slot. 
 
     
     
       2. The hinge clutch structures defined in  claim 1  wherein the friction band structure comprises a stop structure that stops rotation of the base mount structure and the shaft relative to the friction band at a particular rotational orientation of the friction band structure relative to the shaft. 
     
     
       3. The hinge clutch structures defined in  claim 2  wherein the spring is connected between the shaft and the friction band structure, wherein the friction band structure has a portion that is crimped over a portion of the spring. 
     
     
       4. The hinge clutch structures defined in  claim 1  wherein the friction band structure has a bent portion crimped over the end of the clutch spring. 
     
     
       5. The hinge clutch structures defined in  claim 1  further comprising:
 an annular retainer ring that is press fit onto the end of the shaft to retain the attached spring. 
 
     
     
       6. The hinge clutch structures defined in  claim 1  wherein the spring is connected between the shaft and the friction band structure. 
     
     
       7. The hinge clutch structures defined in  claim 6  wherein the base mount structure is attached to the first housing portion, wherein the friction band structure is attached to the second housing portion, and wherein the different first and second widths create asymmetric opening and closing forces when the first and second housing portions are opened and closed with respect to each other. 
     
     
       8. A portable computer, comprising:
 an upper housing that contains a display; 
 a lower housing; 
 a hinge with which the upper housing is rotatably attached to the lower housing, wherein the hinge has friction band structures including first and second friction bands of unequal widths along a hinge shaft; 
 magnetic latch structures mounted to the upper and lower housings that hold the upper housing in place against the lower housing. 
 
     
     
       9. The portable computer defined in  claim 8  wherein the hinge has a base mount structure attached to the lower housing and wherein the friction band structures are attached to the upper housing. 
     
     
       10. The portable computer defined in  claim 9  wherein the hinge comprises a spring having one end connected to the shaft and another end connected to the friction band structures. 
     
     
       11. The portable computer defined in  claim 10  wherein shaft is press fit into the base mount structure and wherein the friction band structures have a portion that is crimped over the end of the spring that is connected to the friction band structures. 
     
     
       12. The portable computer defined in  claim 11  wherein the friction band structures have a stop structure and wherein the shaft comprises a shelf that arrests relative motion of the friction band and the shaft when the stop structure contacts the shelf. 
     
     
       13. A hinge clutch that connects upper and lower housing portions in a portable computer, comprising:
 a shaft; 
 friction band structures that rotate relative to the shaft, wherein the friction band structures comprise first and second friction bands wrapped around the shaft that create friction that opposes relative rotational movement between the shaft and the friction band structures; and 
 a spring connected between the shaft and the friction band structures, wherein the friction band structures have a portion that is crimped over an end of the spring, wherein the spring has a neutral point that coincides with the upper housing portion having a roughly vertical position relative to the lower housing portion, wherein the spring provides a closing force when the upper housing portion is opened past the roughly vertical position relative to the lower housing portion, and wherein the spring provides an opening force when the upper housing portion is closed past the roughly vertical position related to the lower housing portion. 
 
     
     
       14. The hinge clutch defined in  claim 13  wherein the first friction band has a first dimension along the shaft, wherein the second friction band has a second dimension along the shaft that is different than the first friction band, and wherein the shaft has a slot that receives the spring at an end of the spring opposite to the end of the spring over which the portion of the friction band structures is crimped. 
     
     
       15. The hinge clutch defined in  claim 14  further comprising:
 an annular retainer ring located over the end of the spring received in the slot, wherein the annular retainer ring compresses the slot of the shaft onto the end of the spring received in the slot; and 
 a protective cap located over the shaft and over the end of the spring received in the slot.

Description:
This application claims the benefit of provisional patent application No. 61/105,031, filed Oct. 13, 2008, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This invention relates to electronic devices and, more particularly, to clutch structures for hinges in electronic devices such as portable computers. 
     Portable computers typically have upper and lower housing portions that are connected by a hinge. The lower housing portion contains components such as printed circuit boards, disk drives, a keyboard, and a battery. The upper housing portion contains a display. When the computer is in an open configuration, the upper housing portion is vertical and the display is visible to the user of the portable computer. When the computer is closed, the upper housing lies flat against the lower housing. This protects the display and keyboard and allows the portable computer to be transported. 
     Portable computer hinges are challenging to design. It is generally desirable to make a hinge easy to manipulate. A hinge with an overly stiff clutch mechanism may require a user of the computer to use undesirably large amounts of force to pry open the display when using the computer. Stiff hinge clutches may resist opening to such an extent that the entire base of the computer will be lifted upwards if a user attempts to open a display using only one hand. To address these concerns, clutches may be made that are less stiff. Although clutches such as these may be more pleasing to use, they may not always prevent unintended movement of the upper housing relative to the main housing. 
     It would therefore be desirable to be able to provide improved clutch structures for hinges in electronic devices such as portable computers. 
     SUMMARY 
     A portable computer with improved hinge clutch structures is provided. A clutch may be provided that has asymmetric closing and opening forces produced by friction band members of different sizes. A protective cap may be formed over the tip of the clutch to prevent damage to nearby wires. A slotted tip may be provided on a clutch shaft to engage a clutch spring. A lobe may be formed in the spring in the vicinity of the slotted tip to provide stress relief. A retaining ring may help to retain the end of the clutch spring in the slot. 
     The clutch spring may be directly attached to a friction band portion of the clutch by a bent portion of the friction band portion. This direct engagement arrangement allows complex multi-part structures to be avoided. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative portable computer with hinge clutch structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of an illustrative hinge clutch mechanism in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of an illustrative hinge clutch mechanism showing how a friction band in the mechanism may have a stop structure in accordance with an embodiment of the present invention. 
         FIG. 4  is a side view of an illustrative hinge clutch mechanism showing how the end of a clutch spring may be directly attached to a bent portion of a friction band in accordance with an embodiment of the present invention. 
         FIG. 5  is a perspective view of an illustrative hinge clutch mechanism showing how a cable may be routed along the length of the clutch mechanism when the clutch mechanism is used within the clutch barrel of a portable computer housing and how a protective cap may be used to prevent cable damage in accordance with an embodiment of the present invention. 
         FIG. 6  is a perspective view of an illustrative hinge clutch mechanism showing how a clutch shaft may be provided with a slot at its tip to receive a clutch spring and how the spring may have a stress relief lobe to enhance reliability in accordance with an embodiment of the present invention. 
         FIG. 7  is an end view of an illustrative hinge clutch mechanism showing how the end of a clutch spring may be directly gripped by a bent portion of a friction band in accordance with an embodiment of the present invention. 
         FIG. 8  is a perspective view of an illustrative hinge clutch mechanism showing how an annular retainer ring may be press fit onto the end of a clutch shaft to help hold the end of a clutch spring to the shaft in accordance with an embodiment of the present invention. 
         FIG. 9  is a graph showing the forces involved when using a counterbalanced clutch in a laptop computer with magnetic latches in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates to portable computer structures such as hinge structures. 
     An illustrative electronic device such as a portable computer in which the portable computer hinge structures may be provided is shown in  FIG. 1 . As shown in  FIG. 1 , portable computer  10  may have a housing  12 . Housing  12 , which is sometimes referred to as a case, may be formed from one or more individual structures. For example, housing  12  may have a main structural support member that is formed from a solid block of machined aluminum or other suitable metal. One or more additional structures may be connected to the housing  12 . These structures may include, for example, internal frame members, external coverings such as sheets of metal, etc. Housing  12  and its associated components may, in general, be formed from any suitable materials such as such as plastic, ceramics, metal, glass, etc. An advantage of forming housing  12  at least partly from metal is that metal is durable and attractive in appearance. Metals such as aluminum may be anodized to form an insulating oxide coating. 
     Case  12  may have an upper portion  26  and a lower portion  28 . Lower portion  28  may be referred to as the base or main unit of computer  10  and may contain components such as a hard disk drive, battery, and main logic board. Upper portion  26 , which is sometimes referred to as a cover or lid, may rotate relative to lower portion  28  about rotational axis  16 . Portion  18  of computer  10  may contain a hinge and associated clutch structures and is sometimes referred to as a clutch barrel. 
     Lower housing portion  28  may have a slot such as slot  22  through which optical disks may be loaded into an optical disk drive. Lower housing portion may also have a touchpad such as touchpad  24  and may have keys  20 . If desired, additional components may be mounted to upper and lower housing portions  26  and  28 . For example, upper and lower housing portions  26  and  28  may have ports to which cables can be connected (e.g., universal serial bus ports, an Ethernet port, a Firewire port, audio jacks, card slots, etc.). Buttons and other controls may also be mounted to housing  12 . 
     If desired, upper and lower housing portions  26  and  28  may have transparent windows through which light may be emitted (e.g., from light-emitting diodes). This type of arrangement may be used, for example, to display status information to a user. Openings may also be formed in the surface of upper and lower housing portions to allow sound to pass through the walls of housing  12 . For example, openings may be formed for microphone and speaker ports. With one illustrative arrangement, speaker openings such as speaker openings  30  may be formed in lower housing portion  28  by creating an array of small openings (perforations) in the surface of housing  12 . 
     A display such as display  14  may be mounted within upper housing portion  26 . Display  14  may be, for example, a liquid crystal display (LCD), organic light emitting diode (OLED) display, or plasma display (as examples). A glass panel may be mounted in front of display  14 . The glass panel may help add structural integrity to computer  10 . For example, the glass panel may make upper housing portion  26  more rigid and may protect display  14  from damage due to contact with keys or other structures. 
     Computer  10  may have input-output components such as touch pad  24 . Touch pad  24  may include a touch sensitive surface that allows a user of computer  10  to control computer  10  using touch-based commands (gestures). A portion of touchpad  24  may be depressed by the user when the user desires to “click” on a displayed item on screen  14 . 
     Hinge  18  may include clutch structures. These clutch structures provide friction and stabilizing forces that allow a user to smoothly open and close lid  26  of computer  10 . A satisfactory hinge  18  has clutch structures that are not excessively resistive. A hinge with an overly resistive clutch will make it difficult to open lid  26  of housing  12  smoothly. For example, a stiff hinge may cause lower housing  28  to lift up from a table top as a user attempts to lift lid  26 . At the same time, a weak hinge will not be satisfactory. If a hinge is too weak, small disturbances will cause lid  26  to fall open or slam shut. 
     A hinge clutch mechanism that addresses these issues is shown in  FIG. 2 . As shown in  FIG. 2 , clutch  32  may have a base mount structure  34  and a friction band structure  36 . Base mount  34  may have holes  38  through which screws may be passed to screw base mount  34  to lower housing portion  28 . Friction band  36  may have holes  40  in planar surface  42  through which screws may be passed to screw friction band  36  into upper housing portion  26 . When opening and closing upper housing portion  26  (i.e., the lid of computer  10 ), base mount member  34  tends to remain stationary, while friction band  36  rotates relative to base mount  34  about rotational axis  62 . 
     The movement of friction band  36  relative to base mount  34  is opposed by friction and by the tension of spring  68 . Spring  68  may be formed from a spring member formed in a spiral shape around shaft  50 . Friction is provided using two friction bands that engage shaft  50 . Friction band  54  is wrapped partly around shaft  50  in direction  56 , whereas friction band  58  is wrapped partly around shaft  50  in direction  60 . Because bands  54  and  58  are wrapped in opposing directions, when the friction of one band is weakened, the other will be strengthened. In particular, as the grip of one band on shaft  50  is being loosened due to “unwrapping,” the grip of the other band on shaft  50  is being strengthened due to “wrapping.” 
     Shaft  50  may be attached to base mount  34  through a press fit at attachment point  64 . At end  52  of shaft  50 , spring  68  may be press fit to shaft  50 . Shaft  50  may have a structure that helps form a non-slipping attachment to spring  68 . For example, shaft  50  may be augmented with a gripping texture, a knurl, glue, facets, etc. These features may be used to prevent slippage between spring  68  and shaft  50 . Sleeve  66  may provide lubrication as spring  68  is tightened and relaxed. 
     Bent portion  44  may be crimped over an end of spring  68  in slot  46 . Directly attaching friction band  36  to spring  68  in this way avoids the need for complex multielement parts for forming friction band  36 . For example, friction band  36  may be formed from a single piece of patterned and bent sheet metal (as an example). 
     Spring  68  may be formed from a spring metal (e.g., music wire). Shaft  50 , base member  34 , and friction band  36  may be formed from metal such as steel. Sleeve  66  may be formed from plastic or other durable material. 
     Friction band  36  may have a stop feature  70 . When cover  26  of computer  10  is opened to its maximum extent, stop  70  will bear against mating stop feature  72  of  FIG. 3 . As shown in  FIG. 3 , stop  72  may be formed as a shelf that is an integral part of shaft  50 . If desired, stop  72  may be formed from an extended portion of base mount  34 . 
       FIG. 4  shows how end  74  of spring  68  may be directly attached to bent portion  44  of friction band  36 . Central screw hole  40  may help to provide additional holding power when attaching friction band  36  to display housing  26 . 
     As shown in  FIG. 4 , the width W 1  of band  54  may be different than the width W 2  of band  58 . As a result, the rotational friction that is produced by bands  54  and  58  may not be equal. In this type of situation, clutch  32  may be referred to as exhibiting asymmetric friction. In the example of  FIG. 4 , width W 2  is about 25% larger than width W 1 , so the friction imposed by clutch  32  when friction band  36  is rotated in direction  60  relative to base unit  38  (i.e., when opening cover  26 ) is less than the friction imposed by clutch  32  when friction band  36  is rotated in direction  56  relative to base unit  38  (i.e., when closing cover  26 ). This asymmetrical force distribution can improve the operation of hinge  18 . 
     For example, the relatively higher closing friction that is produced may combat “kickback” of display  26  from spring  68  in certain usage scenarios (i.e., when using computer  10  with display  26  wide open and holding base  28  at an angle relative to the ground). The higher closing friction provided by an asymmetrical friction band may also help to prevent cover  26  from falling closed. The lighter opening friction provided by band  54  may be desirable to provide a light-to-the touch user experience. The lighter opening friction may also avoid situations in which the base is lifted from the table as the user opens the laptop display. 
     In some situations it may be desirable to run cables through hinge  18  from lower housing portion  28  to upper housing portion  26 . An illustrative path that may be traced by a cable is shown in  FIG. 5 . As shown in  FIG. 5 , cable  78  may pass tip region  52  of shaft  50 . To prevent wear to cable  78  from spring  68  in region  52 , a protective member such as protective cap  76  may be used to cover tip  52  of shaft  50  and spring  68 . This may help to ensure longer cable life as a user repeatedly opens and closes cover  26 . Protective cap  76  may be formed from an open ring-shaped structure or may be formed from a closed bowl-shaped structure. Metal, plastic, or other suitable materials may be used to form protective cap  76 . Cap  76  may be attached using adhesive, by press fitting cap  76  onto spring  68  and shaft  50 , etc. 
     As shown in  FIG. 6 , shaft  50  may be provided with a slot at tip  52  such as slot  80 . The end of spring  68  may be press fit into slot  80 . A lobe such as lobe  82  may be provided in spring  68  in the vicinity of the slot attachment point to provide stress relief for spring  68  and thereby enhance reliability. 
     An end view of clutch  32  showing how end  74  of spring  68  may be directly gripped in gap  46  by bent portion  44  of friction band  36  is shown in  FIG. 7 .  FIG. 7  also shows how lobe  82  may extend outward from rotational axis  62  to ensure that spring  68  does not experience a sharp bend at slot attachment point  80 . As shown in  FIG. 8 , an annular retainer such as retainer ring  84  may be press fit onto end  52  of shaft  50  and spring  68 . Retaining structures such as ring  84  may help to compress slot  80  onto the end of spring  68  and may help to retain lobe  82 . Retaining structures may thereby ensure a secure attachment between spring  68  and shaft  50  and improve reliability. Ring  84  may be configured to strengthen shaft  50  and resist stresses caused by spring  68  during hinge cycling. If desired, retaining structure  84  may be configured to serve as a protection structure such as protection structure  76  of  FIG. 5 . 
     Spring  68  provides a counterbalanced force for hinge  68 . The neutral point for spring  68  may be configured to coincide with a roughly vertical position for upper housing  26  relative to lower housing  28 . When a user opens upper housing  26  past this amount, spring  68  unwinds and exhibits an opposing (closing) force. This return force helps to prevent cover  26  from falling open and, when a user is closing the cover from a very open position, this force assists the user in overcoming gravity. When a user closes housing  26  past the neutral position, spring  68  is tightened. When spring  68  is tightened in this way, spring  68  generates an opposing (opening force) on cover  26 . 
     The counterbalanced nature of clutch spring  68  therefore helps to stabilize the motion of cover  28 . If desired, cover  26  and base  28  of computer  10  may be provided with magnetic latch structures (illustrated as magnetic structures  15  in  FIG. 1 ). These magnetic structures may be formed by combinations of magnets and magnetic materials such as steel. When the user closes cover  26 , the magnetic latch structures hold cover  26  closed. Magnetic latch mechanisms such as these typically exert a force, even at a distance. 
     A graph showing the forces involved when using a counterbalanced clutch  32  in a laptop computer with magnetic latches such as magnetic latch structures  15  of  FIG. 1  is shown in  FIG. 9 . At small display angles, the top edge of cover  26  is near to the near edge of lower housing portion  28 . In this situation, magnets  15  are close to each other and exhibit strong forces, as indicated by line segments  92  and  94 . 
     Counterbalance spring  68  in clutch  32  creates opening force and closing force curves that intersect when display  26  is nearly vertical (i.e., when the spring contribution to the clutch force is minimal because spring  68  is at its neutral position). Inclusion of counterbalance spring  68  in clutch  32  helps to provide lower operating forces and more uniform operating forces. The need for strong friction from the friction band  36  is also reduced. Friction from bands  54  and  58  is, however, advantageous in that this friction helps to arrest unwanted motion of display  26 . If desired, the friction bands in clutch  32  may be sized equally to provide symmetric friction (i.e., equal opening and closing frictions). In this situation, the opening and closing forces exhibited by display  26  will be characterized by solid lines  86  and  88 . The use of unequally sized friction bands such as bands  54  and  58  of  FIG. 2  provides clutch  32  with asymmetric friction (i.e., unequal opening and closing frictions). If band  58  is made larger than band  54 , the increased closing friction contribution of band  58  may help to prevent display  26  from being too easy to close without providing the hinge with excess friction. This is illustrated by dashed line  90 , which corresponds to the closing force exhibited by an asymmetric clutch such as clutch  32 . 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20081215
Publication Date: 20120313
Grant Date: 20120313
Priority Date: 20081013
Inventors: DEGNER BRETT W.
KESSLER PATRICK
LIGTENBERG CHRIS
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1681", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1679", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1681", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1679", "inventive": true, "first": false, "tree": "[]"}, {"code": "E05D11/084", "inventive": false, "first": false, "tree": "[]"}, {"code": "E05D11/084", "inventive": false, "first": false, "tree": "[]"}, {"code": "E05Y2999/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "E05Y2999/00", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 42097556