PATENT DOCUMENT

Publication Number: US-8885355-B2
Application Number: US-201113177246-A
Country: US
Kind Code: B2

Title: Device having snaps with soldered snap members

Abstract:
A structure such as a button may have a substrate. Components such as switches may be mounted on the substrate. The substrate may be a printed circuit board with solder pads. A snap member may be soldered to one of the solder pads. A metal clip may have a snap arm with an opening. The metal clip may be attached to the printed circuit board. When attached, the opening in the snap arm may mate with the snap member that is soldered to the solder pad on the printed circuit board. The printed circuit board may be attached to a button housing member. A button cover member may be attached to the clip. A ground connection may be formed between the metal clip and the snap member by providing the snap member with structures that bear against the metal clip and form an electrical connection.

Claims:
What is claimed is: 
     
       1. Apparatus, comprising: a substrate; a metal clip, wherein a portion of the metal clip forms a snap arm with an opening; a snap member, wherein the snap member has a portion that protrudes into the opening and a portion that is soldered to the substrate and wherein the snap member comprises a solderphilic coating; and a plastic member that is mounted to the clip. 
     
     
       2. The apparatus defined in  claim 1  wherein the substrate comprises a printed circuit board. 
     
     
       3. The apparatus defined in  claim 2 , wherein the printed circuit board is electrically coupled to an audio jack. 
     
     
       4. The apparatus defined in  claim 2 , wherein the printed circuit board is electrically coupled to a plurality of speakers. 
     
     
       5. The apparatus defined in  claim 1  wherein the plastic member comprises a button cover. 
     
     
       6. The apparatus defined in  claim 5  wherein the button cover comprises a heat stake with which the button cover is attached to the clip. 
     
     
       7. The apparatus defined in  claim 1  further comprising a low-contact-resistance coating over at least a portion of the solderphilic coating. 
     
     
       8. The apparatus defined in  claim 1  wherein the snap member comprises a spring structure that bears against a portion of the snap arm. 
     
     
       9. The apparatus defined in  claim 1  further comprising an upper device housing portion and a lower device housing portion, wherein the snap member and the snap arm are mounted between the upper housing portion and the lower housing portion.

Description:
This relates generally to snap structures and, more particularly, to snap structures for use in assembling electronic device structures to form electronic devices. 
     Electronic devices often contain circuit components that are mounted to printed circuit boards. A finished device may include structures that cover external surfaces of the device. The covering structures may help isolate internal components such as printed circuit boards and switches from the environment and may provide a cosmetic exterior surface for the device. In a device such as a button, part of a covering structure may serve as a flexible button cover that is pressed by a user during operation of a button. 
     Challenges can arise in attaching exterior structures such as covering structures to internal components such as printed circuit boards in a button or other device. In some devices, snaps are used in attaching pieces of a device together. If care is not taken, however, the use of snaps may cause delicate structures to break, may not allow covering structures to be attached properly, may lead to undesirable fabrication complexity, and may give rise to other difficulties. 
     It would therefore be desirable to be able to provide improved snap structures for devices such as buttons. 
     SUMMARY 
     A structure such as a button or other device may have a printed circuit board or other substrate. Components such as switches and other circuitry may be mounted on the substrate. 
     The substrate may be a printed circuit board with solder pads. A snap member may be soldered to one of the solder pads. The snap member may be formed from a bent metal strip, from a machined or cast metal structure, or other suitable snap structure. 
     A metal clip may have a snap arm with an opening. The metal clip may be attached to the printed circuit board using a snap formed from the snap member and the snap arm. When attached, the opening in the snap arm may mate with the snap member that is soldered to the solder pad on the printed circuit board. 
     The printed circuit board may be attached to a button housing member. A button cover member may be attached to the clip. The button cover may be formed from a flexible plastic structure that is heat staked to the metal clip. 
     A ground connection may be formed between the metal clip and the snap member. To ensure a low-contact-resistance path between the clip and the snap member, the snap member may be provided with structures such as spring structure that bear against the metal clip and form an electrical connection. 
     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 headset that contains a button in accordance with an embodiment of the present invention. 
         FIG. 2  is an exploded perspective view of an illustrative button having snaps formed in accordance with an embodiment of the present invention. 
         FIG. 3  is a side view of an illustrative snap formed using a snap arm with an opening and a snap member that protrudes into the opening and that is soldered to a solder pad on a printed circuit board in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an interior portion of an illustrative button having a snap structure formed from a bent metal strip in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional end view of an illustrative button having snaps in accordance with an embodiment of the present invention. 
         FIG. 6  is a perspective view of an interior portion of a button having a snap member formed from a solid metal structure in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional end view of an illustrative button having a snap in accordance with an embodiment of the present invention. 
         FIG. 8  is a perspective view of a portion of a printed circuit board in a button of the type shown in  FIG. 1  showing how pads on the printed circuit board may be attached to signal and ground wires in accordance with an embodiment of the present invention. 
         FIG. 9  is a perspective view of snap member with a spring-shaped arm that may be used in forming an electrical contact with a snap arm on a clip in accordance with an embodiment of the present invention. 
         FIG. 10  is a side view of a snap member with a protruding spring shape for forming an electrical connection with a snap arm that is formed from part of a clip in accordance with an embodiment of the present invention. 
         FIG. 11  is a perspective view of an illustrative snap member having a spring portion for forming a ground connection in accordance with an embodiment of the present invention. 
         FIG. 12  is a flow chart of illustrative steps involved in manufacturing devices having snaps in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic equipment such as computers, handheld devices, cellular telephones, media players, portable devices, accessories, and other equipment often contain internal device components mounted on substrates such as printed circuit boards. Consider, as an example, headset  10  of  FIG. 1 . Headset  10  may contain speakers such as left and right speakers  24  and  26 . Wires  12  may be used to couple speakers  24  and  26  to audio jack  22 . Wires  12  may contain two wires  14  that provide signals to speaker  24  and two wires  16  that provide signals to speaker  26 . Button  28  may be coupled to a pair of button wires. The two button wires that are coupled to button  28  and the two speaker wires in path segment  16  may form a set of four wires  18 . Segment  20  of wire path  12  may contain six wires (two from path  14  and four from path  18 ). These wires may be coupled to the contacts in audio jack  22 . 
     Button  28  may contain different portions such as portions  30 ,  32 , and  34 , each of which may be associated with different operations (e.g., functions associated with controlling an attached portable device). 
     Devices such as button  28  and other electronic equipment may contain components such as switches, integrated circuits, and other circuitry and components that are mounted to a substrate. The substrate may be, for example, a rigid printed circuit board, a flexible printed circuit board, a plastic carrier, or other suitable substrate. The exterior of button  28  may be covered with a button cover structure. To accommodate flexing, it may be desirable to form the button cover of a flexible material such as plastic. 
     To facilitate attachment of device structures, it may be desirable to provide a device with one or more snaps. A snap may have a first portion (sometimes referred to as a snap arm or snap member) that has an opening. The snap may also have a second portion (sometimes referred to as a snap prong or snap member) that mates with the opening. The second portion may have a ramp-shaped surface that helps deflect the snap arm so that the prong enters the hole in the snap arm. Because the ramp-shaped surface of the second portion of the snap can be used in leading the snap arm over the prong, the second snap portion may sometimes be referred to as a lead-in member. 
     Snaps based on snap arms and snap lead-in members may be used in interconnecting any suitable structures (e.g., mechanical structures, electrical structures, substrates such as rigid and flexible printed circuit board, structures, housing structures such as button covers and other external covering structures and/or internal housing structures, or other suitable mechanical and/or electrical structures). The use of snaps in assembling portions of a device such as button  28  of  FIG. 1  is merely illustrative. Snaps may be used in connecting any suitable structures, if desired. 
       FIG. 2  is an exploded perspective view of button  28 . As shown in  FIG. 2 , button  28  may have an upper housing such as button cover structure  36  (sometimes referred to as a button cover or button cover member) and a lower housing such as lower button housing structure  42 . Button cover  36  may, if desired, be formed from a soft plastic such as a blend of polycarbonate and acrylonitrile butadiene styrene (PC/ABS) and may have labels corresponding to the different functions that may be performed by a tethered device when a user presses regions  30 ,  32 , and  34 , respectively. 
     Button  28  may contain internal components such as switches  44  that are mounted to substrate  40 . Substrate  40  may be a rigid printed circuit board (e.g., a printed circuit board formed from fiberglass-filled epoxy), a plastic carrier (e.g., a plastic carrier with patterned metal traces), a flexible printed circuit board assembly (e.g., a flex circuit formed from a flexible polymer sheet with conductive traces that has been mounted on a support structure), or other suitable substrate. Switches  44  may be any suitable switches such as dome switches or tactile (“tac”) switches that contain rectangular housings, internal dome switch members, a covering film, and electrical contacts that are soldered to traces in printed circuit board substrate  40 . 
     During operation, a user of button  28  may press inwardly on a button region such as region  30 ,  32 , or  34  to activate an associated one of switches  44 . A flexible member such as flexible metal member  38  may be interposed between button cover  36  and substrate (e.g., printed circuit board)  40 . Flexible metal member  38  (which may sometimes be referred to as a clip or clip member) may be used as an interface structure that assists in attaching button member  36  to printed circuit board  40 . When a user presses on a region such as region  30 ,  32 , or  34 , the associated portion of clip  38  will bend downward and will actuate a corresponding one of switches  44 . 
     Clip  38  may be formed from a flexible metal such as a thin sheet of stainless steel (e.g., stainless steel having a thickness of less than 0.5 mm, less than 0.2 mm, or less than 0.1 mm, as examples). Clip  38  may be formed into a desired shape by a metal stamping tool, laser cutting, machining with a cutting tool, etc. 
     Button cover  36  may have integral heat stake members that are coupled to clip  38 . Clip  38  may have snap features such as snap arms  48 . Snap arms  48  may have engagement features such as holes  50  or other openings. Holes  50  may be configured to mate with corresponding snap members such as prongs  46 . Prongs  46  may have sloped surfaces that form a lead-in shape that helps to bend arms  48  out and over prongs  46  when clip  38  is pressed downwards towards printed circuit board  40  during assembly. Prongs  46  may therefore sometimes be referred to as snap lead-in members. 
     To facilitate large volume assembly, it may be desirable to form snap lead-in members  46  from structures that may be mounted on printed circuit board using surface mount technology (SMT). For example, lead-in members  46  may be formed from solder-compatible structures that can be soldered to board  40  using pick-and-place tools. Any suitable number of snaps may be used in connecting button cover  36  to printed circuit board  40 . In the examples of  FIG. 2 , two snaps are used. 
     Printed circuit board  40  may be attached to lower housing portion  42  using heat stakes or other suitable attachment mechanisms. 
       FIG. 3  is a cross-sectional side view of clip  38  and printed circuit board  40  in the vicinity of a snap (snap  102 ). Snap  102  may include snap arm  48  and mating snap lead-in member  46 . Initially, clip  38  may have the position shown in dashed lines. When pressed downward in direction  104  arm  48  strikes lead-in member  46 . Surface  46 A of lead-in member  46  is angled away from the planar surface of printed circuit board  40  (i.e., at angle A in  FIG. 3 ), so surface  46 A helps to bend arm  48  in direction  70  as clip  38  is moved in direction  104 . As clip  38  continues to move in direction  104 , arm  48  rides up an over lead-in member  46  until hole  50  in arm  48  has moved into alignment with lead-in member  46 . Once aligned, arm  48  will spring back in direction  72  until reaching the position shown in  FIG. 3 . In this position, the prong formed by snap lead-in member  46  will protrude into hole  50  and will engage arm  48 . By forming the size of prong  46  to match the size of hole  50 , excessive motion between button cover  36  and printed circuit board  40  can be avoided. 
     To facilitate high volume manufacturing, snap lead-in member  46  may be formed from a structure that is suitable for mounting to printed circuit board  40  using surface mount technology (SMT) mounting techniques (e.g., mounting using solder and a pick-and-place tool). As shown in  FIG. 3 , for example, solder  56  may be formed under planar portion  46 B of lead-in member  46  and may be used to solder lead-in member  46  to metal trace (solder pad)  58  on the upper surface of printed circuit board  40 . 
       FIG. 4  is a perspective view of an interior portion of button  28 . As shown in  FIG. 4 , snap lead-in member  46  may be implemented using a bent metal strip. Other configurations may be used for lead-in member  46  if desired (e.g., bent pieces of metal with different shapes, cast metal parts, machined metal structures, structures formed from other materials such as plastic that have been coated with metal, structures formed from composites, etc.).  FIG. 5  is a cross-sectional end view of clip  38 , printed circuit board  40 , and lower housing  42  in a configuration in which clip  38  is being lowered towards lead-in member  46  during assembly. 
       FIG. 6  is a perspective view of an illustrative interior portion of button  28  showing how snap lead-in member  46  may be formed from a cast metal structure in which the ramped lead-in surface of the member is formed from a portion of the body of the lead-in member itself, rather than the surface of a bent piece of metal that extends upward from the lower portions of the snap lead-in member. 
       FIG. 7  is a cross-sectional end view of button  28  showing how button cover  36  may have integral heat stakes such as heat stack  36 A and showing how lower housing  42  may have integral heat stakes such as heat stake  42 A. Heat stakes such as heat stake  36 A or other fastening mechanism may be used to attach button cover  36  to clip  38 . Heat stakes such as heat stake  42 A or other fastening mechanism may be used to connect housing portion  42  to printed circuit board  40 . Snaps such as snap  102  may be used to attach clip  38  and therefore button cover  36  to printed circuit board  40  and therefore lower housing  42 . 
     Each snap  102  may include a snap arm such as snap arm  48  and a snap lead-in member such as snap lead-in member  46  that mates with an opening in snap arm  48 . Snap arm  48  preferably has sufficient flexibility to ride over the protrusion formed by lead-in member  46  when clip  38  is pressed into place. 
     To reduce the likelihood of damage to circuitry such as switches  44  during electrostatic discharge events, it may be desirable to ground metal button parts such as clip  38 . With one suitable arrangement, a grounding path for clip  38  may be provided through lead-in member  48  and ground path  74 . Ground path  74  may be formed, for example, be conductive traces in printed circuit board  40  that connect to a ground terminal. 
     As shown in  FIG. 8 , a ground terminal in button  28  may be formed by pads such as pads  76  on printed circuit board  40 . Wires such as wires  82  and  84  may pass through button  28  without electrically connecting to the switches of button  28  (e.g., to form the two wires in path segment  16  of  FIG. 1 ). Wires such as wires  78  and  80  may be coupled to pads  76 . Wire  78  may be a ground wire and wire  80  may be a signal wire for carrying button data (as an example). In this type of configuration, the pad  76  to which wire  78  is coupled may form a ground terminal and may be coupled to ground traces  74  ( FIG. 7 ). 
     When forming an electrostatic discharge grounding path between clip  38  and lead-in member  46 , electrical contact may be made between clip  38  and lead-in member  46  using spring structures or other structures that are suitable for creating low-contact-resistance paths. Illustrative locations at which lead-in member  46  may contact clip  38  include locations A, B, and C in  FIG. 6 . Spring structures for forming electrical connections with clip  38  at locations A, B, and C may, if desired, be formed as integral parts of lead-in member  46 . 
       FIG. 9  is a perspective view of an illustrative configuration that may be used for lead-in member  46  showing how lead-in member  46  may have a structure such as spring structure  86  that forms a contact with clip  38 . Spring structure  86  may, for example, make electrical contact with clip  38  by pressing point  87  of spring structure  86  against clip  38  at location C ( FIG. 6 ). 
       FIG. 10  is a side view of an illustrative lead-in member having a region such as region  88  that may form a contact with clip  38  at location A ( FIG. 6 ). As illustrated in  FIG. 10 , lead-in member  46  (and, if desired, clip  38 ) may contain multiple layers of material. For example, lead-in member  46  may include a base member  90 , a first coating  92 , and a second coating  93 . Base member  90  may be formed from a material such as stainless steel or spring metal (e.g., a beryllium copper alloy). Coating  92  may be a blanket coating that is formed over the entire surface of member  90 . Coating  92  may be, for example, a nickel coating that provides member  90  with a solder-attracting (solderphilic) coating. Costing  93  may be, for example, a localized coating of a material such as gold that exhibits low contact resistance when pressed against other metals. 
       FIG. 11  is a perspective view of an illustrative configuration for lead-in member  46  in which lead-in member  46  has a spring structure such as spring structure  95  that make electrical contact with clip  38  by pressing point  94  of spring structure  95  against clip  38  at location B ( FIG. 6 ). 
     Illustrative steps involved in forming electrical devices such as button  28  of  FIG. 1  or other components using snaps such as snap  102  are shown in  FIG. 12 . 
     At step  96 , the structure that form button  28  and snaps  102  may be formed. For example, injection molding or other techniques may be used to form parts such as button cover  36  and housing  42  from plastic. Stamping or machining techniques may be used to form metal parts such as clip  38  and the metal parts that make up lead-in member  46 . Coatings such as solderphilic and low-resistance coatings may be applied to clip  38  and/or lead-in member  46 . 
     At step  98 , lead-in members  46  may be soldered to mating solder pads on printed circuit board  40  using a pick-and-place tool or other equipment. 
     At step  100 , the structures that form button  28  such as button cover  36 , clip  38 , snaps  102  (formed from snap members such as snap arms  48  and snap members such as lead-in members  46 ), printed circuit board  40 , and lower housing  42  may be assembled to form a finished structure (e.g., button  28  or other device). For example, button cover  36  may be heat staked to clip  38 , housing structure  42  may be heat staked to printed circuit board  40 , and the snap arm members and snap lead-in members in snaps  102  may be connected together. Electrical connections between clip  38  and ground in printed circuit board  40  may be formed by using spring portions of lead-in member  46  to press against corresponding portions of arm  48 . 
     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: 20110706
Publication Date: 20141111
Grant Date: 20141111
Priority Date: 20110706
Inventors: STANLEY CRAIG MATTHEW
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K2201/10053", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/301", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/09063", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/0311", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2223/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/86", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H9/0228", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49144", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49144", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/09063", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/0311", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10053", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/301", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2223/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/86", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H9/0228", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K5/15", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K5/15", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K2201/10053", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H9/0228", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K5/0013", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K3/301", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/0311", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/09063", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/86", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 47438543