PATENT DOCUMENT

Publication Number: US-7293749-B2
Application Number: US-49538506-A
Country: US
Kind Code: B2

Title: Self aligning foot assembly

Abstract:
A foot assembly includes a foot including a snap and a first alignment feature, the snap and the alignment feature are coupled to a base, and the first alignment feature extending a greater distance from the base than an engagement of the snap. The assembly also includes a foot socket coupled to the foot, the socket including an undercut and a second alignment feature. In one aspect, the second alignment feature interfaces with the first alignment feature. In another aspect, the socket is coupled to an enclosure of a portable computing device.

Claims:
1. A foot comprising:
 a base; 
 a snap extending from the base, the snap having a proximal end and a distal end, wherein the proximal end is coupled to the base and the distal end includes an engagement pawl; and 
 a post extending from the base, the post having a proximal end and a distal end, wherein the proximal end is coupled to the base and the distal end extends a greater distance from the base than the engagement pawl. 
 
   
   
     2. The foot of  claim 1 , wherein the foot comprises three snaps. 
   
   
     3. The foot of  claim 2 , wherein each snap includes a pawl. 
   
   
     4. The foot of  claim 2 , wherein the foot is bilaterally symmetric. 
   
   
     5. The foot of  claim 2 , wherein snaps are asymmetrically positioned on the base. 
   
   
     6. The foot of  claim 2 , wherein the snaps are substantially equally spaced about the perimeter of the base. 
   
   
     7. The foot of  claim 2 , wherein the post is positioned about the perimeter of the base between two snaps. 
   
   
     8. The foot of  claim 1 , wherein post is to align the snaps to a socket for the foot. 
   
   
     9. The foot of  claim 1 , wherein the base is substantially cylindrical. 
   
   
     10. The foot of  claim 1 , wherein the foot is coupled to an enclosure of a portable computing device. 
   
   
     11. A foot socket comprising:
 a base; 
 a raised center portion coupled to the base by a plurality of supports, wherein a first support includes a first vertical rib, and a second support includes a slot; and 
 a plurality of undercuts coupled to the base, wherein each undercut is adjacent to two supports. 
 
   
   
     12. The socket of  claim 11 , wherein the slot is to align with a post of a foot. 
   
   
     13. The socket of  claim 11 , wherein socket is bilaterally symmetric. 
   
   
     14. The socket of  claim 11 , further comprising a third support. 
   
   
     15. The socket of  claim 14 , wherein the third support includes a second vertical rib. 
   
   
     16. The socket of  claim 14 , further comprising three undercuts. 
   
   
     17. The socket of  claim 11 , wherein the base is cylindrical. 
   
   
     18. The socket of  claim 11 , wherein the center portion is substantially ring shaped. 
   
   
     19. The socket of  claim 11 , wherein the socket is coupled to an enclosure of a portable computing device. 
   
   
     20. A foot assembly comprising:
 a foot including a snap and a first alignment feature, wherein the snap and the alignment feature are coupled to a base, the first alignment feature extending a greater distance from the base than an engagement of the snap; and 
 a foot socket coupled to the foot, the socket including an undercut and a second alignment feature, wherein the second alignment feature interfaces with the first alignment feature. 
 
   
   
     21. The assembly of  claim 20 , wherein the engagement is a pawl. 
   
   
     22. The assembly of  claim 21 , wherein the base is cylindrical. 
   
   
     23. The assembly of  claim 21 , wherein the first alignment feature is a post. 
   
   
     24. The assembly of  claim 23 , wherein the second alignment feature is a slot. 
   
   
     25. The assembly of  claim 24 , wherein the foot comprises three snaps. 
   
   
     26. The assembly of  claim 25 , wherein the socket comprises three undercuts to engage the pawls of the snaps. 
   
   
     27. The assembly of  claim 26 , wherein the socket comprises a plurality of vertical ribs. 
   
   
     28. The assembly of  claim 20 , wherein the socket is coupled to an enclosure of a portable computing device.

Description:
This application is a divisional of U.S. patent application Ser. No. 10/796,545, filed on Mar. 8, 2004, now U.S. Pat. No. 7,095,610. 

   TECHNICAL FIELD 
   This disclosure relates generally to a foot assembly, and in particular, to a self aligning foot assembly for use with portable computing devices. 
   BACKGROUND OF THE INVENTION 
   Portable computing devices, also referred to as notebook or laptop computers, typically have feet disposed on their bottom surfaces. The feet raise the portable computer off of a supporting surface, such as a desk or table. This may serve several purposes, such as preserving the finish of the bottom surface of the portable computer, or improving cooling of the portable computer, among others.  FIG. 1A  illustrates a computing device  120 , such as a typical portable computer. Portable computing device  120  includes a display housing rotatably coupled to a main housing or enclosure through a hinge. The display housing includes a display screen. The main housing includes a keyboard and a pointing device. Additional aspects of the internal circuitry of a computer such as computing device  120  may be found in U.S. Pat. No. 6,222,549, which is incorporated by reference herein. The main housing includes a base which is the bottom surface of the main housing. A portable computer  120  typically includes four feet  100  disposed on the bottom of an enclosure  106 , as illustrated in  FIG. 1B .  FIG. 1B  illustrates a bottom view of the computing device  120  illustrated in  FIG. 1A . Each foot  100  is typically positioned at a corner of the bottom surface of an enclosure  106  of the portable computer  120 . The foot  100  is part of a foot assembly  110 , which includes the foot  100  and a foot socket  104 . 
     FIG. 1C  illustrates an exploded view of a prior art foot assembly  110  for a portable computer, such as the computer  120  illustrated in  FIG. 1A . Computer  120  includes an internal supporting chassis  108  to which various hardware components of the computer are attached, such as for example a motherboard, memory, and battery. The chassis  108  is typically comprised of a metal or another rigid material. At the point on the chassis  108  where a foot assembly  110  is to be located, the chassis  108  includes an internally threaded screw bore  109  to accommodate a machine screw  102 . The screw  102  is fastened through a foot socket  104  into the bore  109  to retain the enclosure  106  to the supporting chassis  108 . The enclosure  106 , or case, is typically comprised of a rigid material, and houses the components of the computer. The enclosure  106  includes a recessed well  107  to accommodate the socket  104 . Once the screw  102  is installed, the head of screw  102  remains exposed within the center portion of the socket  104 . To cover the head of screw  102 , a foot  100  is installed into the foot socket  104 . 
     FIG. 1D  illustrates a perspective view of the prior art foot  100 . Foot  100  includes three snaps  150  extending from a cylindrical base  152 . The three snaps  150  are positioned radially about the perimeter of the base  152 , and are spaced equally from each other. Clearances  101  are positioned between adjacent snaps  150 . The snaps  150  are radially symmetrically positioned about the perimeter of the base  152 . Foot  100  is radially symmetric about the central axis of base  152 . Each snap  150  is attached to the base  152  at a proximal end, and each snap  150  has a substantially wedge shaped cross section. A pawl  153  is an engagement disposed at the distal end of each snap  150  from the base. Pawl  153  includes an edge on the end of each snap  150 . Pawl  153  is designed such that when installed into foot socket  104 , the pawl  153  catches the snap  150  on the foot socket  104  so as to prevent the foot  100  from disengaging the foot socket  104 .  FIG. 1E  illustrates a top view of the foot  100 .  FIG. 1F  illustrates a cross-sectional side view of the foot  100  taken along the section A-A in  FIG. 1E .  FIG. 1G  illustrates a cross-sectional side view of the foot  100  taken along the section B-B in  FIG. 1E . 
     FIG. 1H  illustrates a perspective view of a prior art foot socket  104 . Foot socket  104  includes a substantially cylindrical base  111  and a raised center portion  112 . Foot socket  104  is radially symmetric about the central axis of base  111 . The base  111  is disc shaped, with a bore in the center. The raised center portion  112  has a substantially circular shape, and is coupled to the base  111  by three raised supports  113 . The supports  113  are spaced equally about the base  111 . The socket  104  is indexed in the well  107  using a ledge  121  so that the socket  104  may only be placed in the well  107  in a single rotational orientation. 
     FIG. 1I  illustrates a top view of the foot socket  104 .  FIG. 1J  illustrates a cross-sectional side view of the foot socket  104  taken along the section A-A in  FIG. 1I .  FIG. 1K  illustrates a cross-sectional side view of the foot socket  104  taken along the section B-B in  FIG. 1I .  FIG. 1L  illustrates a bottom view of the foot socket  104 .  FIG. 1M  illustrates a cross-sectional side view of the foot socket  104  taken along the section C-C in  FIG. 1L . The raised center portion  112  includes an aperture  114  to accommodate screw  102 . When screw  102  is installed into chassis  108 , the head of screw  102  is adjacent to an exterior (or bottom) side  118  of the socket  104 , while the interior (or top) side  117  of the socket  104  is adjacent to the surface of well  107  of the enclosure  106 . Socket  104  includes three circular cosmetic features  190  on the exterior surface  118  of the base  111 . Foot socket  104  includes three undercuts  115  disposed between adjacent supports  113 . Undercuts  115  are coupled to the base  111  and extend towards the central axis of the base  111 . Undercuts  115  are edges on which pawl  153  catches when foot  100  is installed into the foot socket  104 . Foot socket  104  includes three vertical orientation ribs  116 . Each vertical rib  116  is disposed on the exterior side  118  of each support  113 , and extends along the length of each support  113  between the base  111  and the center portion  112 . 
   The dimensions of the prior art foot  100  are now described. Referring to  FIG. 1F , the diameter of base  152  is 8.00 mm with a tolerance of −0.10 mm. The diameter of the snaps  150  about the base  152  is 6.20 mm with a tolerance of −0.10 mm. The angle of pawl  153  is 15.0 degrees from perpendicular of the upper surface of base  152 . The overall height of foot  100  from the lower surface of base  152  to the upper surface of the snaps  150  is 3.60 mm. The edge of each snap  150  has a 0.30 mm radius or blend (R0.30) applied to the edge between the upper and side surfaces of the snap  150 . The inner diameter between the snaps  150  is 3.00 mm. The diameter of the snaps  150  at pawls  153  is 6.70 mm with a tolerance of ±0.05. The height of pawls  153  from the upper surface of base  152  is 0.96 mm with a tolerance of ±0.05 mm. The height of base  152  is 1.84 mm with a tolerance of ±0.010 mm. Referring to  FIG. 1G , the edge of the base  152  a 0.50 mm radius or blend (R0.50) applied to the edge between the upper and side surfaces of the base  152 . The foot  100  has a volume of about 115.12 mm 3 . 
   The dimensions of the prior art foot socket  104  are now described. Referring to  FIG. 1I , arc angle  170  between the center of support  113  and the edge of support  113  is 30 degrees. Arc angle  171  of support  113  is 50 degrees. Arc angle  172  between undercuts  115  is 60 degrees. Arc angle  173  between adjacent supports  113  is 70 degrees with a tolerance of ±0.50 degrees. Referring to  FIG. 1J , the height of undercut  115  from the lower surface of base  111  is 1.80 mm with a tolerance of ±0.05 mm. The depth of ledge  121  from support  113  is 0.5 mm with a tolerance of +0.05 mm. Referring to  FIG. 1K , the interior surface of the three supports  113  at base  111  are positioned about a diameter of 9.50 mm. The diameter of the center portion  112  is 7.89 mm with a tolerance of −0.05 mm. The diameter of aperture  114  is 2.80 mm. The angle of support  113  is 15 degrees from perpendicular of base  111 . The center portion has a depth of 0.80 mm with a tolerance of −0.10 mm. The height of the lower surface of undercut  115  from the lower surface of base  111  is 0.50 mm. The height of the lower surface of undercut  115  from the upper surface of undercut  115  is 0.26 mm. The base  111  is 1.20 mm thick, with a tolerance of ±0.05 mm. The upper surface of center portion  112  is 3.00 mm above the upper surface of base  111 , with a tolerance of −0.05 mm. The overall height of socket  104  is 4.20 mm. The outer diameter of the base  111  is 15.00 mm. The inner diameter of base  111  is 8.20 mm with a tolerance of +0.10 mm. The diameter of the outer portion of the three undercuts  115  is 7.56 mm. Referring to  FIG. 1L , the angle  175  between cosmetic features  190  is 120 degrees. Referring to  FIG. 1M , the depth of cosmetic features  190  is 0.5 mm, and the diameter of the cosmetic feature  190  is 1.7 mm. 
   SUMMARY OF THE DESCRIPTION 
   A self aligning foot assembly is described herein. The following provides a summary of some, but not all, embodiments described within this disclosure; it will be appreciated that certain embodiments which are claimed will not be summarized here. In one exemplary embodiment, a foot includes a base, and a snap extending from the base, the snap having a proximal end and a distal end. In one aspect, the proximal end is coupled to the base and the distal end includes an engagement pawl. The foot also includes a post extending from the base, the post having a proximal end and a distal end. In one aspect, the proximal end of the post is coupled to the base and the distal end extends a greater distance from the base than the engagement. In one aspect, the foot is coupled to an enclosure of a portable computing device. 
   In another exemplary embodiment, a foot socket includes a base, and a raised center portion coupled to the base by a plurality of supports. In one aspect, a first support includes a first vertical rib, and a second support includes a slot. The socket also includes a plurality of undercuts coupled to the base, where each undercut is adjacent to two supports. In another aspect, the socket is coupled to an enclosure of a portable computing device. 
   In yet another exemplary embodiment, a foot assembly includes a foot including a snap and a first alignment feature, the snap and the alignment feature are coupled to a base, and the first alignment feature extending a greater distance from the base than an engagement of the snap. The assembly also includes a foot socket coupled to the foot, the socket including an undercut and a second alignment feature. In one aspect, the second alignment feature interfaces with the first alignment feature. In another aspect, the socket is coupled to an enclosure of a portable computing device. 
   The present invention is described in conjunction with hardware of varying scope. In addition to the aspects of the present invention described in this summary, further aspects of the invention will become apparent by reference to the drawings and by reading the detailed description that follows. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
       FIG. 1A  illustrates a portable computing device  120 . 
       FIG. 1B  illustrates a bottom view of the computing device  120 . 
       FIG. 1C  illustrates an exploded view of a prior art foot assembly  110  for a portable computer. 
       FIG. 1D  illustrates a perspective view of the prior art foot  100 . 
       FIG. 1E  illustrates a top view of the foot  100 . 
       FIG. 1F  illustrates a cross-sectional side view of the foot  100  taken along the section A-A in  FIG. 1E . 
       FIG. 1G  illustrates a cross-sectional side view of the foot  100  taken along the section B-B in  FIG. 1E . 
       FIG. 1H  illustrates a perspective view of a prior art foot socket  104 . 
       FIG. 1I  illustrates a top view of the foot socket  104 . 
       FIG. 1J  illustrates a cross-sectional side view of the foot socket  104  taken along the section A-A in  FIG. 1I . 
       FIG. 1K  illustrates a cross-sectional side view of the foot socket  104  taken along the section B-B in  FIG. 1I . 
       FIG. 1L  illustrates a bottom view of the foot socket  104 . 
       FIG. 1M  illustrates a cross-sectional side view of the foot socket  104  taken along the section C-C in  FIG. 1L . 
       FIG. 2A  illustrates an exploded view of an embodiment of a self aligning foot assembly  200 . 
       FIG. 2B  illustrates a perspective view of an embodiment of a foot  202 . 
       FIG. 2C  illustrates a top view of an embodiment of the foot  202 . 
       FIG. 2D  illustrates a cross-sectional side view of an embodiment of the foot  202  taken along the section A-A in  FIG. 2C . 
       FIG. 2E  illustrates a cross-sectional side view of an embodiment of the foot  202  taken along the section B-B in  FIG. 2C . 
       FIG. 2F  illustrates a perspective view of an embodiment of a foot socket  204 . 
       FIG. 2G  illustrates a top view of an embodiment of the foot socket  204 . 
       FIG. 2H  illustrates a cross-sectional side view of an embodiment of the foot socket  204  taken along the section A-A in  FIG. 2G . 
       FIG. 2I  illustrates a cross-sectional side view of an embodiment of the foot socket  204  taken along the section B-B in  FIG. 2G . 
       FIG. 2J  illustrates a bottom view of an embodiment of the foot socket  204 . 
       FIG. 2K  illustrates a cross-sectional side view of an embodiment of the foot socket  204  taken along the section C-C in  FIG. 2J . 
   

   DETAILED DESCRIPTION 
   In the following detailed description of embodiments of the invention, reference is made to the accompanying drawings in which like references indicate similar elements, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical, functional, and other changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims. 
     FIG. 2A  illustrates an exploded view of an embodiment of a self aligning foot assembly  200 . Foot assembly  200  includes an alignment feature to assist a user in the proper installation of the foot  202  into a corresponding foot socket  204 . In one embodiment, the foot assembly  200  may be used with a portable computing device  120  such as that illustrated in  FIGS. 1A and 1B . A foot assembly  200  is coupled to a supporting chassis  206  with a machine screw  208 . The chassis  206  and screw  208  may be made of a metal, a metal alloy, a ceramic, a plastic, or combinations thereof. In alternative embodiments, other rigid materials may be used. The chassis  206  includes an internally threaded screw bore  210  to accommodate the screw  208 . The screw  208  is installed into the bore  210  to mechanically fasten the enclosure  212  and a foot socket  204  to the supporting chassis  206 . The enclosure  212  is typically comprised of a rigid material, and houses the components of the computer. The enclosure  212  may be made of a metal, a metal alloy, a ceramic, a plastic, or combinations thereof. In alternative embodiments, other rigid materials may be used. The enclosure  212  includes a recessed well  214  to accommodate the socket  204 . The screw  208  is fastened through the foot socket  204  into the bore  210  to retain the enclosure  212  to the supporting chassis  206 . Once the screw  208  is installed, the head of screw  208  remains exposed within the center of the socket  204 . To cover the head of screw  208 , a foot  202  is installed into the foot socket  204 . In one embodiment, the foot  202  serves both cosmetic and functional purposes. 
     FIG. 2B  illustrates a perspective view of an embodiment of a foot  202 . Foot  202  includes three snaps  250   a ,  250   b ,  250   c  extending from a cylindrical base  252 . The three snaps  250   a ,  250   b ,  250   c  are positioned radially about the perimeter of the base  252 . In one embodiment, snaps  250   a  and  250   b  are each spaced an equal distance from snap  250   c . In another embodiment, the snaps  250   a ,  250   b ,  250   c  are spaced substantially equally from each other. In one embodiment, the outermost arc lengths of the snaps  250   a ,  250   b  and  250   c  are substantially equal. In another embodiment, the outermost arc lengths of the snaps  250   a  and  250   b  are substantially equal. 
   Foot  202  also includes a post  260 . Post  260  is an alignment feature or key which is used for proper rotational alignment and orientation of the foot  202  with the socket  204 . In one embodiment, post  260  is positioned between snaps  250   a  and  250   b . Post  260  is coupled to the base  252  at a proximal end. In one embodiment, post  260  extends substantially perpendicular from base  252 . In one embodiment, the distance of the distal end of post  260  from base  252  is substantially equal to the distance of the distal end of the snaps  250  from the base  252 . In one embodiment, post  260  has a substantially trapezoidal cross-section. 
     FIG. 2C  illustrates a top view of the foot  202 . The top view illustrates the non-visible portion of the foot which is not exposed when the foot  202  is installed into the socket  204 .  FIG. 2D  illustrates a cross-sectional side view of the foot  202  taken along the section A-A in  FIG. 2C .  FIG. 2E  illustrates a cross-sectional side view of the foot  202  taken along the section B-B in  FIG. 2C . A clearance  201   a  is positioned between adjacent snaps  250   a  and  250   c . A clearance  201   b  is positioned between adjacent snaps  250   b  and  250   c . In one embodiment, foot  202  is bilaterally symmetric with respect to section A-A of  FIG. 2C . Each snap  250   a ,  250   b ,  250   c  is attached to the base  252  at a proximal end of the snap  250 . In one embodiment, each snap  250   a ,  250   b ,  250   c  has a substantially wedge shaped cross section. A pawl  253  is an engagement disposed at the distal end of each snap  250   a ,  250   b ,  250   c  from the base  252 . Pawl  253  includes an edge near the distal end of each snap  250   a ,  250   b ,  250   c . Pawl  253  is designed such that when foot  202  is installed into foot socket  204 , the pawl  253  catches the snap  250   a ,  250   b ,  250   c  on the foot socket  204  so as to prevent the foot  202  from disengaging the foot socket  204 . In one embodiment, the post  260  extends from the base  252  a greater distance or height than the distance which the pawl  253  extends from the base  252 . Advantages of the post  260  being taller than the pawl  253  engagement are discussed below. 
   In one embodiment, the foot  202  is made using a double-shot injection mold process. By double-shot, it is meant that the foot  202  is made through a two step process using two materials. The foot is molded by injecting a first shot of a base material into a mold, followed by a second shot of material into the mold. In one embodiment, a first shot of a rigid material, such as ABS plastic, is overmolded with a second shot of an elastomeric material, such as rubber. ABS plastic includes any of a class of plastics based on acrylonitrile-butadiene-styrene copolymers. It will be appreciated that other materials may be used. For example, instead of ABS plastic, other rigid materials, such as other plastics, a metal, a metal alloy, a ceramic, or combinations thereof may be used. In another embodiment, other flexible materials may be used besides rubber. In one embodiment, the second shot is comprised of a thermoplastic polyurethane elastomer (TPU), such as ELLASTOLAN® TPU available from BASF Corporation, Mount Olive, N.J. Referring again to  FIG. 2D , an embodiment of the foot  202  is illustrated in which a first material, for example ABS plastic, is used to mold the post  260  and an outer portion of the snaps  250 . In another embodiment, a second material, for example rubber, is used to mold an inner portion of the snaps  250  and the base  252  of the foot  202 . In one embodiment, the post  260  is extruded. In an alternate embodiment, the foot  202  may be made of a single material, injected in a single shot. In one embodiment, the foot  202  has a mass of about 0.17 grams. In one embodiment, foot  202  has a total volume of about 145.3 mm 3 . 
     FIG. 2F  illustrates a perspective view of an embodiment of a foot socket  204 . Foot socket  204  includes a substantially cylindrical base  211  and a raised center portion  212 . The base  211  is disc shaped, with a bore in the center. The raised center portion  212  has a substantially circular shape, and is coupled to the base  211  by three supports  213   a ,  213   b ,  213   c . In one embodiment, the supports  213   a ,  213   b ,  213   c  are positioned radially about the base  211 . The center portion  212  has diameter that is less than the diameter of the base  211 . In one embodiment, the socket  204  is indexed in the well  214  using a ledge  226  so that the socket  204  may only be placed in the well  214  in a single rotational orientation. 
     FIG. 2G  illustrates a top view of the foot socket  204 .  FIG. 2H  illustrates a cross-sectional side view of the foot socket  204  taken along the section A-A in  FIG. 2G .  FIG. 2I  illustrates a cross-sectional side view of the foot socket  204  taken along the section B-B in  FIG. 2G .  FIG. 2J  illustrates a bottom view of the foot socket  204 .  FIG. 2K  illustrates a cross-sectional side view of the foot socket  204  taken along the section C-C in  FIG. 2J . In one embodiment, the socket  204  is bilaterally symmetric about section A-A in  FIG. 2G . The raised center portion  212  includes an aperture  225  to accommodate screw  208 . When screw  208  is installed into chassis  206 , the head of screw  208  is adjacent to a bottom or an exterior side  218  of the socket  204 , while the top or interior side  217  of the socket  204  is adjacent to the surface of well  214  of the enclosure  212 . In one embodiment, socket  204  includes three circular cosmetic features  290  on the exterior surface  218  of the base  211 . Foot socket  204  includes three undercuts  215   a ,  215   b ,  215   c . Each undercut  215  is disposed between two adjacent supports  213 . For example, in one embodiment, undercut  215   a  is disposed between supports  213   a  and  213   c . The undercuts  215   a ,  215   b ,  215   c  are coupled to the base  211  and extend towards the central axis of the base  211 . In one embodiment, undercuts  115  are substantially flat, curved edges on which pawl  253  catches when foot  202  is installed into the foot socket  204 . 
   In one embodiment, foot socket  204  includes two vertical orientation ribs  216 . In one embodiment, a vertical rib  216  is disposed on the exterior side  218  of each of supports  213   b  and  213   c , and runs along the length of each support  213   b ,  213   c  between the base  211  and the center portion  212 . The vertical ribs  216  are designed to assist in the alignment of the snaps  250  during installation of the foot  202  into the socket  204 . The ribs  216  are designed to avoid the snaps  250  from aligning with the supports  213 . In one embodiment, foot socket  204  does not include a vertical rib on support  213   a . Instead, a recess or slot  220  is disposed on the exterior side of support  213   a.    
   In one embodiment, the socket  204  is die-cast. The socket  204  may be made of a metal, a metal alloy, a ceramic, a plastic, or combinations thereof. In alternative embodiments, other rigid materials may be used. In one embodiment, socket  204  is made of an aluminum alloy, such as ADC 12 . In one embodiment, socket  204  has a volume of about 210 mm 3 . The socket  204  may be plated or painted in various colors and surface textures. In one embodiment, the socket  204  has a mass of about 0.6 grams. 
   Aspects of the physical characteristics of particular embodiments of the present invention are now described. It will be appreciated that variations in materials, shapes, dimensions and angles may be made, among other variations, from the particular embodiments of the invention described below. 
   Referring to  FIG. 2A , in one embodiment, the machine screw  208  is an M2.5 ×5 mm screw. Referring to the illustration of foot  202  in  FIG. 2C , post  260  has an arc angle  270  of about 30 degrees. The arc angle  271  between post  260  and snap  250   b , and between post  260  and snap  250   a , is about 16.18 degrees. The arc angle  272  of each snap  250  is about 67.64 degrees. The arc angle  273  between snaps  250   b  and snap  250   c , and between snaps  250   a  and  250   c  is about 47.36 degrees. Referring to  FIG. 2D , post  260  tapers about 0.34 mm inward starting from about 1.27 mm from the distal end of post  260  from the base  252  towards the distal end of post  260 . In one embodiment, the edge of the base  252  a 0.50 mm radius or blend (R0.50) applied to the edge between the upper and side surfaces of the base  252 . Referring to  FIG. 2E , the diameter of the pawls  253  about the base  252  is about 6.70 mm, with a tolerance of about +0.2 mm. The diameter of the snaps  250  about the base  252  is about 6.20 mm. The height of pawls  253  from the upper surface of base  252  is about 0.96 mm. The height of pawls  253  from the lower surface of base  252  is about 3.40 mm with a tolerance of about −0.10 mm. The height of base  252  is about 2.44 mm with a tolerance of about +0.10 mm. The diameter of base  252  is about 8.00 mm. The overall height of the foot  202  from the lower surface of base  252  to the upper surface of the snaps  250  is about 4.20 mm. 
   Referring to the illustration of socket  204  in  FIG. 2G , in one embodiment, the arc angle  274  of undercut  215   c  is about 70 degrees. The arc angle  275  of support  213   c  is about 40 degrees. The arc angle  276  of support  213   a  is about 50 degrees. The arc angle  277  of undercut  215   b  is about 80 degrees. The arc angle  278  of support  213   b  is about 40 degrees. Referring to  FIG. 2H , the height of the upper surface of undercuts  215  from the lower surface of base  211  is about 1.80 mm with a tolerance of about ±0.05 mm. The depth of ledge  226  from support  213   a  is about 0.50 mm with a tolerance of about +0.05 mm. The depth of the upper surface of slot  220  from the lower surface of the center portion  212  is about 0.70 mm with a tolerance of about −0.10 mm. 
   Referring to  FIG. 2I , in one embodiment, the depth of the upper surface of base  211  from the upper surface of center portion  212  is about 3.00 mm with a tolerance of about −0.05 mm. The overall height of socket  207  is about 4.20 mm. The height of base  211  is about 1.20 mm with a tolerance of about ±0.05 mm. The outer diameter of base  211  is about 15.00 mm. The inner diameter of base  211  is about 8.20 mm with a tolerance of +0.10 mm. The diameter of the respective proximal ends of vertical ribs  216  from the supports  213   b ,  213   c  positioned about base  211  is about 7.56 mm. The height of the lower surface of the vertical ribs  216  from the lower surface of base  211  is about 0.76 mm, with a tolerance of about ±0.05 mm. The center portion  212  is about 0.80 mm thick, with a tolerance of about −0.10 mm. The aperture  225  has a diameter of about 2.80 mm. The diameter of the center portion  212  is about 7.89 mm with a tolerance of about −0.05 mm. The diameter of the supports  213  positioned about base  211  at base  211  is about 9.50 mm. 
   Referring to  FIG. 2J , in one embodiment, arc angle  279  of slot  220  is about 30 degrees. Cosmetic features  290  are spaced about 120 degrees apart about the base  211 . Circular cosmetic features  290  each have a diameter of about 1.70 mm, with a tolerance of about ±0.10 mm. Arc angle  280  of undercut  215   c  is about 60 degrees. Arc angle  281  between undercuts  215   c  and  215   b  is about 50 degrees. Arc angle  282  of undercut  215   b  is about 85 degrees. Referring to  FIG. 2K , the depth of cosmetic features  290  from the lower surface of base  211  is about 0.50 mm with a tolerance of about ±0.10 mm. 
   To summarize certain aspects of the present invention, it will be noted that in the embodiments illustrated in  FIGS. 2A-2K , the foot assembly  200  differs substantially from the prior art foot assembly  110  with respect to several features. In one embodiment, the foot  202  includes an alignment post  260  between two snaps  250   a  and  250   b , whereas the prior art foot  100  illustrated in  FIG. 1D  lacks such a feature. Furthermore, in one embodiment, the foot socket  204  includes a slot  220  on support  213   a  and vertical ribs  216  on the remaining two supports  213   b ,  213   c , whereas the prior art foot socket  104  includes a vertical rib  116  on each of the three supports  113 . The features of embodiments of the present invention have several advantages over the prior art, some of which are now described. 
   Referring again to  FIGS. 1A-1M , ideally during installation of the prior art foot  100 , the pawls  153  of the snaps  150  align with the undercuts  115  of the socket  104 . Under a compression force applied to the foot  100  against the exterior side  118  of socket  104 , the snaps  150  flex towards the center of the foot  100  through cantilever motion, until the pawls  153  catch on the undercuts  115  of the socket  104 , thereby retaining the foot  100  within the socket  104 . However, a user installing the foot  100  into the socket  104  may have difficulty determining whether the snaps  150  are properly aligned with the undercuts  115 . Consequently, when installing a foot  100  into the socket  104 , the foot  100  may be installed in an improper orientation with respect to the socket  104  simply by forcing the foot  100  into the socket  104 . For example, an improper installation orientation may result in a snap  150  being aligned with a vertical rib  116 . 
   During installation of the prior art foot  100  to the prior art socket  104 , the snaps  150  may engage the undercuts  115  before the vertical ribs  116  engage the foot  100 . This is due to the positioning of distal end of the vertical ribs  116  from the center portion  112  being less than or equal to the positioning of the undercuts  115  from the center portion  112 . In other words, during a misaligned installation of a prior art foot  100 , the snaps  150  may engage the undercuts  115  either simultaneously or before the snaps  150  contact the vertical ribs  116 . Thus the vertical ribs  116  may not effectively prevent the snaps  150  from engaging the socket  104  during a misaligned installation. The result is variable foot  100  retention based on the user&#39;s installation orientation. Furthermore, the force exerted on the foot  100  during a misaligned installation may greatly reduce the retention force of the snaps  150  through deflection of the snaps  150 , among other potential damage. Although a misaligned foot  100  may be retained in the socket  104  temporarily, over time and use, the misaligned installation may result in the foot  100  becoming dislodged from the socket  104  and cause the foot  100  to fall out. Although the snaps  150  may help to align the foot  100  with the socket  104 , they do not do so prior to the engagement of the pawls  153  with the undercuts  115 . 
   Embodiments of the present invention provide an alignment feature on the foot assembly  200  between the foot  202  and the socket  204 . In particular, the post  260  of foot  202  is designed to locate or interface with the single slot  220  of foot socket  204 . Thus, in one embodiment, the foot  202  may only be installed into the socket  204  in a single orientation. In one embodiment, when installing the foot  202  into the socket  204 , the user aligns the post  260  on the foot  202  to the slot  220  of the socket  204  in order for all three snaps  250  to engage the undercuts  215  when the foot  202  is depressed into the socket  204 . In one embodiment, when the foot  202  is properly installed, the pawls  253  of the snaps  250  constrain the foot  202  along the Z-axis with respect to the chassis  212 . In one embodiment, since the socket  204  is indexed to a single orientation to the enclosure  212 , the mating post  260  is oriented in the same position with respect to the socket  204  whenever the foot  202  is installed. In one embodiment, a proper alignment of the foot  202  with the socket  204  results in the clearances  201   a  and  201   b  aligning with ribs  216 . 
   As discussed above, in one embodiment, the post  260  of foot  202  extends from the base  252  a greater distance than the distance which the pawl  253  extends from the base  252 . If during installation of the foot  202  into the socket  204 , the foot  202  is misaligned with respect to the socket  204 , the post  260  prevents the snaps  250  from engaging the undercuts  215 . Since the post  260  is taller (i.e. extends a greater distance from the base  252 ) than the pawls  253 , the snaps  250  may not mechanically engage the undercuts  215  of the foot socket  204  until the post  260  is located properly to the slot  220  in the socket  204 . During a misaligned installation attempt, the post  260  may collide with either an undercut  215  or a vertical rib  216 . Such a collision will provide tactile feedback to the user indicating a misalignment of the foot  202  with respect to the socket  204 . This allows for the user to correct the alignment prior to the foot  202  being retained in the socket  204 , and thereby avoid potential damage to the foot  202 . 
   Thus the orientation or alignment features of embodiments of the present invention function during installation before the snaps  250  become engaged in socket  204 . During a properly aligned installation, the post  260  aligns with slot  220 , and under an installation load, a compression force on the outer arc of the snaps  250  cause them to flex inwards under cantilever motion until the pawls  253  engage the undercuts  215 , resulting in the foot  202  being retained in the socket  204 . The contribution of user error to diminished foot retention may be minimized through the self aligning features of embodiments of the present invention. In particular, the post  260  aligns with and engages the socket  204  prior to the pawls  253  of snaps  250  engaging the undercuts  215 . Additionally, once the foot  202  is properly installed, the post  260  minimizes the potential for external rotation of the foot  202  to result in the snaps  250  disengaging the socket  204 , by providing a greater degree of tolerance control to the assembly  200  than that of the prior art assembly  110 . 
   It will be appreciated that variations may be made to the various embodiments described above. For example, in one embodiment, the key and slot features of the foot  202  and socket  204  may be switched. In one embodiment, the foot  202  includes a slot which aligns to a post on the socket  204 . In another embodiment, the socket may be eliminated, and the features of the socket integrated into the enclosure. For example, the enclosure may include an integral slot, integral vertical ribs, and integral undercuts, similar to those of the socket  204  described above, to which the foot  202  may align during installation of the foot into the enclosure. In one embodiment, more or less snaps  250  may be included on the foot, and a corresponding number of undercuts and supports may be included on the socket. For example, embodiments are contemplated wherein the foot includes two snaps, and the socket includes two corresponding undercuts. In another exemplary alternative embodiment, the foot  202  includes two posts, and the socket includes a single vertical rib and two slots to accommodate the posts of the foot. 
   The above description of illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. These modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.

Metadata:
Filing Date: 20060727
Publication Date: 20071113
Grant Date: 20071113
Priority Date: 20040308
Inventors: BANKO JOSHUA DAVID
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/1656", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 36821755