PATENT DOCUMENT

Publication Number: US-9394733-B2
Application Number: US-201314099653-A
Country: US
Kind Code: B2

Title: Assembly process for glue-free hinge

Abstract:
Glue-free hinge assemblies including press-fit pins are disclosed. A press-fit pin of one material can mechanically attach to a workpiece of another material during a press fit operation. The press-fit pin can include a pin shaft having a chamfered first end, a notched portion, a grooved portion having axial grooves, a clinching feature, and a sealing feature. The chamfered first end can guide the press-fit pin into a counter-bored receiving hole in the workpiece. The axial grooves can etch the workpiece material to rotationally lock the press fit-pin into the receiving hole. The clinching feature can plastically deform workpiece material into the notched portion to axially lock the press-fit pin into receiving hole without causing substantial axial expansion of the workpiece. The sealing feature can form a stepped fit between an outer diameter of the press-fit pin and an outer diameter of the counter-bored receiving hole.

Claims:
What is claimed is: 
     
       1. A press-fit pin assembly formed of a first material mechanically attached to a workpiece formed of a second material during a press fit operation wherein the second material captures the press fit pin by plastic deformation, the press-fit pin comprising:
 a pin shaft having a chamfered first end; 
 a notched portion located distal to the chamfered first end; 
 a grooved portion having a plurality of axial grooves and located either on a first side of the notched portion proximate the chamfered first end, or on a second side of the notched portion, opposite the first side; and 
 a clinching feature located on the second side of the notched portion, and having a larger diameter than the notched portion; 
 wherein during the press fit operation:
 the chamfered first end guides the press-fit pin into a counter-bored receiving hole in the workpiece, the counter-bored receiving hole having an inner diameter and an outer diameter larger than the inner diameter, 
 the axial grooves etch the second material of the workpiece at either the inner or outer diameter of the receiving hole to rotationally lock the press fit pin into the receiving hole, and 
 the clinching feature plastically deforms a portion of the workpiece into the notched portion to axially lock the press fit pin into the receiving hole without causing substantial axial expansion of the workpiece. 
 
 
     
     
       2. The press-fit pin assembly as recited in  claim 1 , wherein the grooved portion is arranged between the chamfered first end and the notched portion. 
     
     
       3. The press-fit pin assembly as recited in  claim 1 , wherein the grooved portion is arranged proximate to the clinching feature. 
     
     
       4. The press-fit pin assembly as recited in  claim 1 , wherein the first material is made of a metal that is harder than the second material of the workpiece. 
     
     
       5. The press-fit pin assembly of  claim 1 , wherein the outer diameter of the press-fit pin is slightly smaller than the outer diameter of the counter-bored receiving hole. 
     
     
       6. The press-fit pin assembly of  claim 1 , wherein a sealing feature is located adjacent the clinching feature, opposite the notched portion, and the sealing feature is received into the outer diameter of the counter-bored receiving hole to form a stepped fit between an outer diameter of the press-fit pin and the outer diameter of the counter-bored receiving hole. 
     
     
       7. The press-fit pin assembly of  claim 6 , wherein the sealing feature provides a cosmetic seal between the press-fit pin and the workpiece. 
     
     
       8. The press-fit pin assembly of  claim 7 , wherein the cosmetic seal hides from view all of the workpiece portion that is plastically deformed into the notched portion by the clinching feature. 
     
     
       9. The press-fit pin assembly of  claim 1 , wherein the workpiece portion that is plastically deformed into the notched portion by the clinching feature is from a region defined by the inner diameter of the counter-bored receiving hole. 
     
     
       10. The press-fit pin assembly of  claim 1 , wherein the press-fit pin combines with the workpiece to form part of a glue-free hinge assembly. 
     
     
       11. The press-fit pin assembly of  claim 10 , wherein the glue-free hinge assembly is for a tablet device accessory. 
     
     
       12. The press-fit pin assembly of  claim 1 , further comprising:
 a chamfered second end located on the pin shaft opposite the chamfered first end; 
 a second notched portion located proximate the chamfered second end; 
 a second grooved portion having a plurality of axial grooves and located proximate the chamfered second end; 
 a second clinching feature located proximate the chamfered second end; and 
 a second sealing feature located proximate the chamfered second end. 
 
     
     
       13. A glue-free hinge, comprising:
 one or more hinge lugs formed from a first material, each of the one or more hinge lugs having one or more counter-bored receiving holes formed therein, each of the receiving holes having an inner diameter and an outer diameter larger than the inner diameter; and 
 one or more press-fit pins formed from a second material and press-fit into a respective receiving hole from the one or more receiving holes, each of the one or more press-fit pins having:
 a pin shaft having a chamfered first end that guides the press-fit pin into the respective receiving hole, 
 a notched portion located distal to the chamfered first end, 
 a grooved portion having a plurality of axial grooves and located either on a first side of the notched portion proximate the chamfered first end, or on a second side of the notched portion, opposite the first side, wherein the axial grooves etch the first material of the hinge lug at either the inner or outer diameter of the respective receiving hole to rotationally lock the press-fit pin into the respective receiving hole, and 
 a clinching feature located on the second side of the notched portion, and having a diameter larger than the notched portion, wherein the clinching feature plastically deforms a portion of the hinge lug into the notched portion to axially lock the press-fit pin into the respective receiving hole without causing substantial axial expansion of the hinge lug around the respective receiving hole. 
 
 
     
     
       14. The glue-free hinge of  claim 13 , each of the one or more press-fit pins further having: a sealing feature adjacent the clinching feature and opposite the notched portion that is received into the outer diameter of the respective receiving hole to form a stepped fit between an outer diameter of the press-fit pin and the outer diameter of the respective receiving hole. 
     
     
       15. The glue-free hinge of  claim 14 , wherein the sealing feature provides a cosmetic seal between the press-fit pin and the hinge lug. 
     
     
       16. The glue-free hinge of  claim 15 , wherein the cosmetic seal hides from view all of the hinge lug portion that is plastically deformed into the notched portion by the clinching feature. 
     
     
       17. An electronic device accessory, comprising:
 one or more hinge lugs formed from a first material, each of the one or more hinge lugs having one or more counter-bored receiving holes formed therein, each of the receiving holes having an inner diameter and an outer diameter larger than the inner diameter; and 
 one or more press-fit pins formed from a second material and press-fit into a respective receiving hole from the one or more receiving holes, each of the one or more press-fit pins having:
 a pin shaft having a chamfered first end that guides the press-fit pin into the respective receiving hole, 
 a notched portion located distal to the chamfered first end, 
 a grooved portion having a plurality of axial grooves and located either on a first side of the notched portion proximate the chamfered first end, or on a second side of the notched portion, opposite the first side, wherein the axial grooves etch the first material of the hinge lug at either the inner or outer diameter of the respective receiving hole to rotationally lock the press-fit pin into the respective receiving hole, and 
 a clinching feature located on the second side of the notched portion, and having a diameter larger than the notched portion, wherein the clinching feature plastically deforms a portion of the hinge lug into the notched portion to axially lock the press-fit pin into the respective receiving hole without causing substantial axial expansion of the hinge lug around the respective receiving hole.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority from U.S. Provisional Patent Application No. 61/734,895, filed on Dec. 7, 2012, which is hereby incorporated herein by reference in its entity. 
    
    
     BACKGROUND 
     1. Technical Field 
     The described embodiment relates generally to methods for employing press fit technology. More specifically, specially designed press fits can be used in place of adhesive based support fittings enabling a much smaller overall assembly even when the parts involved are sensitive to low levels of surface strain. 
     2. Related Art 
     Anodized components can be susceptible to damage when placed under low levels of strain. When a sufficient amount of strain is put on an anodized part a phenomenon called anodization cracking can occur. Anodization cracking can occur when the underlying substrate of an anodized surface treatment experiences too much surface strain. This surface strain can be caused in some cases by a press-fitting that exerts an undue amount of force on an interior portion of the underlying substrate, essentially causing bulging to occur on the exterior surface of that substrate. Anodization cracking is quite obvious in an end product and generally manifests with a number of ghosting lines or splotches running along the areas where the cracking occurred. Consequently, manufacturers of anodized parts have been justifiably cautious in employing technologies which put strain on anodized parts. Adhesive connections are commonly used when joining anodized parts together. Unfortunately, the use of an adhesive when bonding a pin inside of a channel can result in large components due to the amount of surface area required to achieve a sufficiently strong connection as well as the added cost in time and efficiency in assembly and manufacturing. 
     Therefore, what is desired are improved fastening techniques. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The described embodiments and the advantages thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawings. These drawings in no way limit any changes in form and detail that may be made to the described embodiments by one skilled in the art without departing from the spirit and scope of the described embodiments. 
         FIGS. 1A and 1B  illustrates an accessory for a tablet device; 
         FIG. 2  illustrates components associated with a hinge assembly for a tablet device accessory; 
         FIG. 3A  illustrates a hinge lug designed to be attached to hinge pins with an adhesive compound; 
         FIG. 3B  illustrates a press-fit type hinge lug in accordance with the described embodiment; 
         FIG. 4A  illustrates a side cross-sectional view of a press fit pin arranged just outside a hinge lug with a counter-bored cavity in accordance with the described embodiment; 
         FIG. 4B  illustrates a side cross-sectional view of a press-fit pin embedded within a hinge lug in accordance with the described embodiment; 
         FIG. 4C  illustrates a cross-sectional view taken along a line illustrated in  FIG. 4B  in accordance with the described embodiment; 
         FIG. 4D  illustrates a side cross-sectional view of an alternate press fit pin configuration; 
         FIG. 5A  illustrates an exploded view of a glue-free hinge assembly in accordance with the described embodiment; 
         FIG. 5B  illustrates an exploded view of a glue-free hinge assembly where the short pins have been inserted into the hinge lugs; 
         FIG. 6A  illustrates a perspective view of a hinge assembly fixture; 
         FIG. 6B  illustrates a top view of a hinge assembly fixture with the components for a glue-free hinge assembly mounted on it; 
         FIG. 7  illustrates an assembled hinge assembly and a flap portion ready to be wrapped around the long hinge pin portion of the hinge assembly in accordance with the described embodiment; 
         FIG. 8  shows a flow chart detailing an assembly process for a glue-free hinge assembly in accordance with the described embodiment; and 
         FIG. 9  shows a flow chart detailing another assembly process for a glue-free hinge assembly. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     A representative apparatus and application of methods according to the present application are described in this section. These examples are being provided solely to add context and aid in the understanding of the described embodiments. It will thus be apparent to one skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the described embodiments. Other applications are possible, such that the following examples should not be taken as limiting. 
     In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific embodiments in accordance with the described embodiments. Although these embodiments are described in sufficient detail to enable one skilled in the art to practice the described embodiments, it is understood that these examples are not limiting; such that other embodiments may be used, and changes may be made without departing from the spirit and scope of the described embodiments. 
     Press-fit joints rely on deformation of at least one or sometimes both of the components to be joined together. One component will typically be made of a harder material in order to cause the other component to deform around it in a way that holds it firmly in place. Unfortunately, deformation of a component generally causes changes in the exterior shape of the deforming component. Generally such changes are small and scarcely noticeable but when tolerances are tight and/or the component susceptible to stress in some manner then a standard press-fit might be poorly suited for that job. For example, when a pin is being press-fit into a channel or bearing, the resulting deformation is typically barrel-shaped causing a slight increase in diameter of a component. When an anodized surface treatment is used on the exterior of the component that contains such a channel, the aforementioned barrel-shaped deformation can cause a phenomenon commonly referred to as anodization cracking. Anodization cracking tends to manifest itself in ghosting cracks and splotches along the surface of the anodized component. Consequently, when designing a press-fit process for parts with anodized surfaces a delicate balance must be struck between component deformation and surface strain. 
     In particular, it is important to maintain the surface appearance of anodized surfaces in those situations where the user&#39;s experience of a product includes a strong visual component. For example, a user of an accessory device, such as a Smart Cover® manufactured by Apple, Inc. of Cupertino Calif., can benefit from both the usefulness of the accessory device as well as the visual appearance. Therefore, it is important to maintain the overall look and feel of the accessory device while at the same time assuring a long and useful operational life. Accordingly,  FIG. 1A-1B  shows an accessory device in the form cover assembly  100 . Cover assembly  100  can have a look and feel that complements that of a host device, such as a tablet device, that can add to the overall look and feel of tablet device. Cover assembly  100  is shown in  FIGS. 1A and 1B  attached to the tablet device in an open configuration with the tablet device fully viewable. Cover assembly  100  can include flap portion  102 . In one embodiment, flap portion  102  can have a size and shape in accordance with the tablet device. Flap portion  102  can be pivotally connected to accessory attachment feature  104  on the tablet by way of hinge assembly  106 . 
       FIG. 2  shows hinge assembly  200  as an embodiment of hinge assembly  106 . Hinge assembly  200  can include first hinge portion (also referred to as first hinge lug)  202  and a second hinge portion (or second hinge lug)  204  disposed opposite the first hinge lug. First end lug  202  can be rigidly connected to second end lug  204  by way of long hinge pin  206  (shown in dotted line form) incorporated into a tube portion of flap portion  102 . The longitudinal axis of connecting rod  206  can act as pivot line  208  about which flap portion  102  can pivot relative to the hinge assembly. Long hinge pin  206  can be formed of metal or plastic strong enough to rigidly support cover assembly  100  as well as any objects, such as tablet device, magnetically attached to magnetic attachment feature  104 . 
     In order to prevent metal on metal contact, first hinge lug  202  and second hinge lug  204  can each have protective layers  210  and  212 , respectively, attached thereto. Protective layers (also referred to as bumpers)  210  and  212  which can prevent direct contact between first hinge lug  202  and second hinge lug  204  with a tablet housing. This is particularly important when end lugs  202 ,  204  and the tablet housing are formed of metal. The presence of bumpers  210  and  212  can prevent metal to metal contact between the hinge lugs and the tablet housing, thereby eliminating the chance of substantial wear and tear at the point of contact that can degrade the overall look and feel of tablet device. 
     First end lug  202  and second end lug  204  can be magnetically connected to the tablet device by way of hinge span  214  that is configured to pivot with respect to the hinge lugs. The pivoting can be accomplished using short hinge pins  216  (a portion of which can be exposed). Short hinge pins  216  can rotatably secure hinge span  206  to both first hinge lug  202  and second hinge lug  204 . Hinge span  214  can include magnetic elements. The magnetic elements can be arranged to magnetically attach hinge span  214  to a magnetic attachment feature having a matching arrangement of magnetic elements in the electronic device. In order to fix the magnetic elements in place within hinge span  214 , short hinge pins  216  can be used to secure magnetic elements located at both ends of hinge span  214  reducing the likelihood that the magnetic elements in hinge span  214  will move about having the potential for disrupting the magnetic attachment between hinge span  214  and the magnetic attachment feature in the tablet device. 
       FIG. 3A  illustrates an alternative to hinge lugs  202 , and  204  as end lug  300 . Although end lug  300  is greatly reduced in size, end lug  300  can provide an attachment of similar strength a press-fit attachment as compared to an adhesive joint.  FIG. 3A  is substantially larger than  FIG. 3B  primarily because adhesive attachments require a substantial surface area to achieve an equivalently strong connection when compared to a smaller press fit hinge lug  300 . The hinge lug illustrated in  FIG. 3A  has about the same holding power as the hinge lug illustrated in  FIG. 3B  (the two hinge lugs are shown at the same scale to give an accurate idea of actual size savings). Hinge lug  300  can also have smaller corresponding short hinge pins than hinge lug  202 / 204  as total overlapping area is much less of an issue with a press-fit joint. Hinge lug  300  includes counter-bored cavity  302  designed to interact with press-fit features formed on a hinge pin. Counter-bored cavity  302  has outer diameter  304  and inner diameter  306 . In some other embodiments cavity  302  can have a counter-sunk geometry. 
       FIG. 4A  illustrates a cross-sectional view of hinge pin  400  being inserted into hinge lug  300 . Hinge pin  400  can include a number of press fit features. Hinge lug  300  has counter-bored cavity  302  designed to receive hinge pin  400 . In this embodiment hinge pin  400  can be made of steel and hinge lug  300  can be made of anodized aluminum. Lead in section  402  includes a chamfered portion arranged on a front portion of hinge pin  400  that allows hinge pin  400  to be guided in to inner diameter  306  of counter-bored cavity  302 . Hinge pin  400  also includes grooved portion  404 . Grooved portion  404  has a diameter slightly larger than inner diameter  306 . Upon insertion of hinge pin  400  into inner diameter  306  portion of cavity  302  grooved portion  404  scrapes against the inner surface of inner diameter  306  allowing grooved portion  404  to become somewhat embedded into inner diameter  306 , thereby giving hinge pin  400  strong anti-rotation properties. Grooved portion  404  is followed by notch portion  406 . Notch portion  406  is then followed by clinch feature  408 . Finally, sealing feature  410  steps the diameter of hinge pin  400  out to its full diameter, which can be just slightly smaller than outer diameter  304 . 
       FIG. 4B  illustrates the effects on hinge lug  300  of pressing hinge pin  400  into it. Dashed portions  450  shows the original dimensions of hinge lug  300  before hinge pin  400  was pressed into it. As hinge pin  400  is pushed into counter-bored cavity  302 , the leading edge of clinch feature  408  comes into contact with the rim of inner diameter  306 . Since steel is harder than aluminum the rim of inner diameter  306  can be plastically deformed into the open area created by notch portion  406 . Once deformed portion  452  of hinge lug  300  fills notch portion  406  of hinge pin  400 , hinge pin  400  is essentially locked in place. The combination of grooved portion  404 , which prevents rotation and deformed portions  452  which prevent forward and rearward travel solidly embeds hinge pin  400  in counter-bored cavity  302 . Sealing feature  410  can have a diameter just slightly smaller than outer diameter  304  allowing sealing feature  410  to provide a cosmetic seal between hinge lug  300  and hinge pin  400 . It should also be noted that as hinge lug  300  is deformed it does not deform only into notch portion  406 . Deformation  454  also occurs during the insertion of hinge pin  400 . Deformation  454  is an unwanted side effect of the pressure exerted upon hinge lug  300  by hinge pin  400 . The size of notch portion  406  and the diameter of clinch feature  408  can be adjusted to minimize the size of deformation  454 , effectively allowing surface strain to be reduced. Consequently, by sufficiently minimizing the size of deformation  454  anodization cracking can be avoided, resulting in a robust low profile glue-free hinge. It should be noted that while this embodiment has been described as a steel hinge pin with an aluminum hinge lug the contemplation of the described embodiment is much wider and the hinge lug can be made from any material that will plastically deform around the hinge pin. 
       FIG. 4C  illustrates a front cross-sectional view of hinge pin  400  inserted into hinge lug  300  along the cross-section line illustrated in  FIG. 4B . In  FIG. 4C  hinge pin  400  is illustrated with a number of grooved portions  404  protruding from it. Grooved portions  404  trace small grooves in a surface portion of counter bored cavity  302  as it is pushed into counter bored cavity  302 . In this way grooved portions  404  become partially embedded in counter bored cavity  302  thereby preventing hinge pin  400  from twisting inside hinge lug  300  when rotational force  462  is put upon it. It should be noted that in some embodiments grooved portions  404  can be so firmly embedded that notch portion  406  fails from rotational force  462  prior to grooved portions  404  becoming dislodged. Consequently in embodiments where greater rotational forces are a more important concern grooved portions  404  can be moved. The next figure will illustrate a hinge pin having grooved portions arranged behind its clinch feature. 
       FIG. 4D  illustrates an alternative hinge pin  480 . Hinge pin  480  has grooved portions  404  disposed behind clinch feature  408 . When a rotational force is applied to hinge pin  408  grooved portions  404  are not acted upon through notch portion  406 . This configuration allows hinge pin  480  to resist rotational forces until embedded grooved portions  404  actually dislodge. Leading portion  482  of hinge pin  480  functions as a leading portion for notch  406  and as a guide for keeping hinge pin  480  properly aligned inside counter bored cavity  302  so that clinch feature  408  properly engages hinge lug  300 . In testing configurations similar to hinge pin  480  yielded an increase in rotational stress resistance of almost two times. Unfortunately, testing showed that such a configuration also resulted in a significant decrease in pull out resistance. Consequently, one or the other configurations can be more or less useful depending on whether design tolerances are stricter in rotational or pull out resistance. 
       FIG. 5A  illustrates an exploded view of glue-free hinge  500 . Glue-free hinge  500  has a number of components. Press-fit attachment features on long hinge pin  502  rigidly connect long hinge pin  502  to hinge lugs  504 . Short hinge pins  506  have press-fit features on one end and are smooth and cylindrical in shape on the other end. The press-fit features on short hinge pins  506  allow short hinge pins  506  to be rigidly coupled to hinge lugs  504 . The smooth, cylindrical ends of short hinge pins  506  allow hinge span  308  to freely rotate about short hinge pins  506 . In  FIG. 5B  the first step in an assembly process is shown. Short hinge pins  506  are inserted into hinge lugs  504 . This operation can be completed by fixing a hinge lug  504  in place and applying force to short hinge pin  506  sufficient to fully engage the press-fit attachment features of short hinge pin  506  inside hinge lug  504 . By pre-fitting hinge lugs  504  with short hinge pins  506  only the press-fit connectors on long hinge pin  502  need to be connected when assembling glue-free hinge  300 . Another advantage of press-fitting short hinge pins  506  in hinge lugs  504  in an earlier operation is that hinge lugs  504  with evidence of anodization cracking can be removed prior to assembly of glue-free hinge  300 . 
       FIG. 6A  illustrates a perspective view of hinge assembly fixture  600 . Hinge assembly fixture  600  is useful primarily due to the relatively thin nature of the long hinge pin. If an unsupported long hinge pin were subjected to the axial forces required to press-fit the ends of the long hinge pin into the hinge lugs, then the long hinge pin can be bent or broken during the operation. Hinge assembly fixture  600  has center block  602  designed to stabilize both the hinge span and long hinge pin while the glue-free hinge is assembled. Center block  602  is mounted upon hinge assembly fixture base  604 . Center block  602  can have channel  606  for stabilizing the long hinge pin and channel  608  for stabilizing the hinge span. The long hinge pin and hinge span can be inserted into center block  602  by lifting upper portion  610  of center block  602  off of lower portion  612 . In this way channels  606  and  608  are exposed and the hinge span and the long hinge pin can be placed in their respective channels. After upper portion  610  of center block  602  is replaced, left lug fixture  614  and right lug fixture  616 , which can be hydraulically driven, are used to press the left and right hinge lugs onto the long hinge pin and hinge span. 
       FIG. 6B  illustrates a top view of hinge assembly fixture  600  with a hinge assembly inserted and ready to be assembled. Hinge lugs  652  can be temporarily, mechanically attached to left and right lug fixtures  614  and  616 . Left and right piston assemblies  654  and  656  can exert hydraulic pressure upon left and right lug fixtures  614  and  616  thereby pushing hinge lugs  652  onto long hinge pin  658  and hinge span  660 . It should be noted that it is important for both hinge lugs  652  to receive an equal amount of force, so that each hinge lug  652  is properly attached to long hinge pin  658 . One way to accomplish this is to put left and right piston assemblies hydraulically in line. In other words each piston assembly would be fed from the same pressurized hydraulic reservoir allowing each to be driven by precisely the same amount of pressure, thereby equalizing the force placed upon each hinge lug  652 . In another embodiment hinge assembly fixture  600  can include only a single piston assembly pushing only one hinge lug on at a time, or bracing the other hinge lug against a fixed surface, thereby also achieving an equalized pressure application on each side of the glue-free hinge assembly. It should be noted that while hinge span  660  is supported by center block  602  it does not require any structural support during the assembly operation as the smooth surfaces of the short pins do not place a significant amount of stress on hinge span  660 . 
       FIG. 7  illustrates a process by which a flap  702  is attached to glue-free hinge assembly  704 . Flap  702  can have tab portion  706  extending from its bottom edge. Tab portion  706  can be a continuation of one layer of flap portion  702 . Tab portion  706  can be long enough to wrap around long hinge pin  706  of glue-free hinge assembly  704 . After tab portion  706  is wrapped around long hinge pin  706  it can be glued back onto flap portion  702 , thereby forming a tube wrapping around long hinge pin  708 . In one embodiment the resulting tube can have a soft interior allowing it to easily rotate around long hinge pin  708 . In this way flap  702  can rotate freely around long hinge pin  708 . In another embodiment flap  702  can have a preformed tube with a slit arranged down the length of the tube, allowing flap portion  702  to be slipped over long hinge pin  708 . It should be noted that while flap  702  can be arranged on long hinge pin  708  prior to assembly of glue-free hinge assembly  704 , doing so would require a portion of flap  702  to be subjected to compression in the hinge assembly fixture described along with  FIGS. 6A and 6B . In some situations where flap  702  is susceptible to damage by compressive forces, this might not be desirable. 
       FIG. 8  shows a flowchart detailing a method for assembling an accessory device. In a first step  802  components of the hinge assembly are received. The hinge assembly components include the following: a hinge span; a long hinge pin; and two hinge lugs each having a pre-inserted short hinge pin. In step  804  the hinge assembly components can be arranged inside a hinge assembly fixture. The hinge assembly fixture includes a center block for stabilizing the long hinge pin and the hinge span during the assembly operation. The hinge assembly fixture can also include hydraulic pistons for pushing the hinge lugs onto the hinge span and long hinge pin. In step  806  two hydraulic pistons can push one hinge lug each onto the stabilized hinge pin and hinge span, resulting in the assembly of the hinge assembly in a single step. In step  808  a tab portion of a flap is wrapped around the long pin portion of the hinge assembly. After the tab portion wraps around the flap it is glued back to the flap resulting in a tube being formed around the long pin. The tube allows the flap to freely rotate around the long pin portion of the hinge assembly 
       FIG. 9  shows a flowchart detailing another method for assembling an accessory device. In a first step  902  two short pins and two anodized hinge lugs are received. The short pins each have one end with press-fit features and another end which is smooth and cylindrical in shape. The hinge lugs each have two counter-bored holes designed to deform around pins having press-fit features similar to the features found on the short pins. In step  904  the press-fit feature end of one short pin is inserted into each hinge lug. In one manufacturing process the anodized hinge lugs can then be inspected for any signs of anodization cracking. If any are spotted the insertion step can be repeated with new pins and hinge lugs. In step  906  one hinge span and one long hinge pin are received. In step  908  the long hinge pin is inserted into a supporting fixture. In some embodiments the hinge span can also be supported in the same fixture to achieve correct spacing between the two components. In step  910  the hinge lugs, each already having a short pin inserted, are simultaneously pressed onto the hinge span and long hinge pin. In one embodiment the pressing of the hinge lugs can be achieved by a hydraulic press system integrated into the supporting fixture while in other embodiments the pressing can be accomplished using any system capable of providing a consistent amount of force over a fixed distance. In another variation of the described embodiment the hinge lugs can be attached one at a time. In step  912  the assembled hinge assembly can be removed from the supporting fixture. In step  914  a flap portion can be attached to the hinge assembly. In one embodiment a tab extending off one side of the flap portion can be wrapped around the long hinge pin portion of the hinge assembly and then glued back to itself. In another embodiment the flap portion can have a formed tub with a slit in it allowing the flap portion to be slipped around the long hinge pin after the hinge assembly is assembled. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20131206
Publication Date: 20160719
Grant Date: 20160719
Priority Date: 20121207
Inventors: FRANKLIN JEREMY C.
LAUDER ANDREW D.
BENTRIM BRIAN
ZHU HAIBING
Assignee: APPLE INC
CPC Classifications: [{"code": "E05D5/127", "inventive": true, "first": true, "tree": "[]"}, {"code": "E05Y2600/506", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T16/525", "inventive": false, "first": false, "tree": "[]"}, {"code": "E05Y2600/506", "inventive": false, "first": false, "tree": "[]"}, {"code": "E05D5/127", "inventive": true, "first": true, "tree": "[]"}, {"code": "E05D5/127", "inventive": true, "first": true, "tree": "[]"}, {"code": "E05Y2600/506", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 51257977