PATENT DOCUMENT

Publication Number: US-9431742-B2
Application Number: US-201514740029-A
Country: US
Kind Code: B2

Title: Spring loaded contacts having sloped backside with retention guide

Abstract:
A spring-loaded contact may include a barrel to form a housing for the spring-loaded contact, a plunger at least partially enclosed by the barrel, a spring enclosed by the barrel, and a sphere between the plunger and the spring. A back of the plunger may be formed at an angle and to include a retention guide, the retention guide partly over the sphere such that the sphere may be in contact with the back of the plunger and the retention guide.

Claims:
What is claimed is: 
     
       1. A spring-loaded contact comprising:
 a barrel to form a housing for the spring-loaded contact; 
 a plunger at least partially enclosed by the barrel; 
 a spring enclosed by the barrel; 
 a first sphere; and 
 a second sphere, 
 wherein a back of the plunger is cup-shaped, wherein the cup-shape has a slot such that the cup-shape receives the first sphere and the slot receives the second sphere. 
 
     
     
       2. The spring-loaded contact of  claim 1  wherein the first sphere is nonconductive. 
     
     
       3. The spring-loaded contact of  claim 1  wherein the second sphere is conductive. 
     
     
       4. The spring-loaded contact of  claim 1  wherein the spring is formed using stainless steel. 
     
     
       5. The spring-loaded contact of  claim 4  wherein the spring is gold-plated. 
     
     
       6. The spring-loaded contact of  claim 4  wherein the spring is coated in a dielectric. 
     
     
       7. The spring-loaded contact of  claim 6  wherein the dielectric is parylene. 
     
     
       8. The spring-loaded contact of  claim 1  wherein the plunger is formed of a copper-based material. 
     
     
       9. The spring-loaded contact of  claim 1  wherein the first sphere and the second sphere are between the back of the plunger and the spring. 
     
     
       10. A spring-loaded contact comprising:
 a barrel to form a housing for the spring-loaded contact, the barrel having a front opening; 
 a spring enclosed by the barrel; 
 a plunger at least partially enclosed by the barrel, the plunger having a body between the spring and the front opening and a contacting portion extending beyond the front opening, a back of the plunger having a cup-shaped depression; and 
 an isolation object in the cup-shaped depression in the back of the plunger, 
 wherein the back of the plunger further comprises a slot, the spring loaded contact further comprising: 
 an additional object located in the slot in the back of the plunger. 
 
     
     
       11. The spring-loaded contact of  claim 10  wherein the isolation object is a sphere. 
     
     
       12. The spring-loaded contact of  claim 11  wherein the isolation object is formed of a ceramic. 
     
     
       13. The spring-loaded contact of  claim 11  wherein the isolation object is formed of a plastic. 
     
     
       14. The spring-loaded contact of  claim 10  wherein the additional object is a sphere. 
     
     
       15. The spring-loaded contact of  claim 14  wherein the additional object is a conductive. 
     
     
       16. The spring-loaded contact of  claim 10  wherein the spring is formed using stainless steel. 
     
     
       17. The spring-loaded contact of  claim 16  wherein the spring is coated in a dielectric, wherein the dielectric is parylene. 
     
     
       18. A spring-loaded contact comprising:
 a barrel to form a housing for the spring-loaded contact, the barrel having a front opening and an opposing rear wall; 
 a plunger at least partially enclosed by the barrel and emerging from the front opening, a back of the plunger having a cup shaped depression and a slot in the cup-shaped depression; 
 an isolation object in the cup-shaped depression in the back of the plunger, 
 an additional object in the slot in the cup-shaped depression; and 
 a spring enclosed by the barrel, the spring between the rear wall and the isolation object. 
 
     
     
       19. The spring-loaded contact of  claim 18  wherein the isolation object is a non-conductive sphere and the additional object is a conductive sphere. 
     
     
       20. The spring-loaded contact of  claim 19  wherein the spring is stainless steel and coated in a dielectric, wherein the dielectric is parylene.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/913,494, filed Jun. 9, 2013, now abandoned, which is a non-provisional of U.S. provisional patent application No. 61/657,862, filed Jun. 10, 2012, which are incorporated by reference. 
    
    
     BACKGROUND 
     The number and types of electronic devices available to consumers have increased tremendously the past few years, and this increase shows no signs of abating. Devices such as portable computing devices, tablet, desktop, and all-in-one computers, cell, smart, and media phones, storage devices, portable media players, navigation systems, monitors and other devices have become ubiquitous. 
     These devices often receive power and share data using various cables. These cables may have connector inserts, or plugs, on each end. The connector inserts may plug into connector receptacles on electronic devices, thereby forming one or more conductive paths for signals and power. 
     These inserts or plugs may have contacts that mate with corresponding contacts in a receptacle. These mated contacts may form portions of electrical paths for data, power, or other types of signals. Various types of contacts may be used. One type of contact, a spring-loaded contact, may be used in either a connector insert or a connector receptacle. 
     Spring-loaded contacts may include a plunger biased by a spring, such that the plunger may be depressed when contacting a second contact, then retracted when disengaged from the second connector. But this arrangement may lead to a reduced reliability for the spring-loaded contact. For example, the spring and plunger may become entangled. That is, the spring may become caught between a plunger and a barrel or housing of the spring-loaded contact. This may prevent the plunger from retracting, thus keeping the plunger depressed. 
     Also, when a plunger makes contact with a second contact and is depressed, the plunger may break contact with the barrel or housing. This may lead to large current flow through the spring, which may in turn damage or destroy the spring. 
     Thus, what is needed are spring-loaded contacts that provide an improved reliability by having a reduced tendency for entanglement between a spring and a plunger, and a reduced chance of large currents flowing through the spring. 
     SUMMARY 
     Accordingly, embodiments of the present invention may provide spring-loaded contacts having an improved reliability. An illustrative embodiment of the present invention may provide a spring-loaded contact. The spring-loaded contact may include a barrel to form a housing for the spring-loaded contact, a plunger at least partially enclosed by the barrel, a spring enclosed by the barrel, and a sphere between the plunger and the spring. A back of the plunger may be formed at an angle and include a retention guide, the retention guide partly over the sphere such that the sphere may be in contact with the back of the plunger and the retention guide. 
     Another illustrative embodiment of the present invention may provide a spring-loaded contact. This spring-loaded contact may include a barrel to form a housing for the spring-loaded contact and a plunger at least partially enclosed by the barrel. The plunger may include a front end to form an electrical connection at a surface of a contact of a connector receptacle and a back end having a surface formed at an angle and including a boss emerging from the surface, the boss forming a retention guide. The spring-loaded contact may further include a spring enclosed by the barrel, and a spherical isolating object located between the plunger and the spring. The spherical isolating object may be in contact with the surface of the back end and the retention guide. 
     Another illustrative embodiment of the present invention may provide another spring-loaded contact. This spring-loaded contact may include a barrel to form a housing for the spring-loaded contact, a plunger at least partially enclosed by the barrel, a spring enclosed by the barrel, a first sphere, and a second sphere. The back of the plunger may be cup-shaped, wherein the cup-shape has a slot such that the cup-shape receives the first sphere and the slot receives the second sphere. 
     Various embodiments of the present invention may incorporate one or more of these and the other features described herein. A better understanding of the nature and advantages of the present invention may be gained by reference to the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a magnetic connector system that may be improved by the incorporation of an embodiment of the present invention; 
         FIG. 2  illustrates a connector insert that may be improved by the incorporation of an embodiment of the present invention; 
         FIG. 3  illustrates a spring-loaded contact according to an embodiment of the present invention; 
         FIG. 4  illustrates the spring-loaded contact of  FIG. 3  where a plunger has been depressed; 
         FIG. 5  illustrates a spring isolation object and a plunger according to an embodiment of the present invention; 
         FIG. 6  illustrates a plunger according to an embodiment of the present invention; and 
         FIG. 7  illustrates a cutaway view of a portion of a spring-loaded contact according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
       FIG. 1  illustrates an electronic system that may be improved by the incorporation of embodiments of the present invention. This figure, as with the other included figures, is shown for illustrative purposes and does not limit either the possible embodiments of the present invention or the claims. 
     This figure includes electronic device  110 . In this specific example, electronic device  110  may be a laptop computer. In other embodiments of the present invention, electronic device  110  may be a netbook or tablet computer, cell, media, or smart phone, global positioning device, media player, or other such device. 
     Electronic device  110  may include a battery. The battery may provide power to electronic circuits in electronic device  110 . This battery may be charged using power adapter  120 . Specifically, power adapter  120  may receive power from an external source, such as a wall outlet or car charger. Power adapter  120  may convert received external power, which may be AC or DC power, to DC power, and it may provide the converted DC power over cable  130  to plug  132 . In other embodiments of the present invention, plug, or insert  132  may be coupled through cable  130  to another type of device. Plug  132  may be arranged to mate with receptacle  112  on electronic device  110 . Power may be received at receptacle  112  from plug  132  and provided to the battery and electronic circuitry in electronic device  110 . In other embodiments of the present invention, data or other types of signals may also be provided to electronic device  110  via plug or insert  132 . 
       FIG. 2  illustrates a connector insert  132  that may be improved by the incorporation of an embodiment of the present invention. Connector insert  132  may include an attraction plate  210 , shield or cover  220 , cable  230 , and strain relief  240 . Attraction plate  210  may include front surface  212 . Front surface  212  may include opening  260  for contacts  250 . 
     In various embodiments of the present invention, contacts  250  may be spring-loaded contacts. Examples of spring-loaded contacts according to embodiments of the present invention are shown in the following figures. 
       FIG. 3  illustrates a spring-loaded contact according to an embodiment of the present invention. Spring-loaded contact  300  may be used as contacts  250  in  FIG. 2 . Spring-loaded contact  300  may be housed in a housing or barrel  310 . Barrel  310  may include tail  312 . Tail  312  may be soldered to a printed circuit board or other structure in a connector, such as connector insert  132  in  FIG. 2 . 
     Spring-loaded contact  300  may further include plunger  320 . Plunger  320  may have tip  322  to mate with a second contact in a connector receptacle. Plunger  320  may further include notch or wider portion  324 . Notch  324  may contact portion  314  of housing  310 , thereby limiting the retraction of plunger  320 . 
     Spring-loaded contact  300  may further include a compliance mechanism, such as spring  330 . Spring  330  may extend to retract plunger  320  from barrel  310  when a connector that houses spring-loaded contact  300  is disengaged from a corresponding connector. Spring  330  may compress, thereby allowing plunger  320  to be depressed into housing or barrel  310  when the connector that houses spring-loaded contact  300  is engaged with the corresponding connector. 
     Again, in conventional spring-loaded contacts, a spring may become entangled with a plunger during use. For example, a spring may become caught between a plunger and a barrel or housing. This may prevent the plunger from retracting fully from the housing. This, in turn, may lead to either or both cosmetic and functional failures. 
     Also, as a plunger is depressed, it may lose contact with a barrel or housing of the spring-loaded contact. Under these circumstances, current may flow through the spring. While this condition may be reasonable when the spring-loaded contact is conveying a signal, it may be damaging when a power supply or ground return is conveyed. This current flow may damage or destroy the spring. Specifically, resistance in the spring may lead to its being heated by the current flow. This heating may cause the spring to lose its elasticity. Such damage may again cause cosmetic or functional failures. 
     Accordingly, embodiments of the present invention may employ a sphere or spherical isolation object  340  between plunger  320  and spring  330 , and angled back to plunger  320 , where the back of plunger  320  further includes retention guide  322 . With these features, when plunger  320  is depressed, plunger  320  maintains contact with barrel  310  and sphere  340  isolates spring  330  such that spring  330  is protected from large currents. 
     In this specific example, sphere  340  contacts plunger  320  at a back surface  326  and at retention guide  322 . Back surface  326  may be angled such that when plunger  320  is depressed, plunger  320  is tilted relative to a center line through spring-loaded contact  300  and maintains contact with barrel  310 . Specifically, the slope or angle at the back surface  326  of plunger  320  forces plunger  320  into a side of barrel  310 . Contact resulting from this force may help to reduce the low-level contact resistance of spring-loaded contact  300 . An example is shown in the following figure. 
       FIG. 4  illustrates the spring-loaded contact of  FIG. 4  where a plunger has been depressed. Specifically, plunger  420  is shown as being depressed relative to housing  410 . In this figure, spring  430  is compressed and sphere  440  is pushed further back into housing  410 . The angled back surface  426  of plunger  420  acts to tilt plunger  420  into housing  410 . Specifically, point  428  of plunger  420  may contact housing or barrel  410  at point  418 . Similarly, point  425  of plunger  420  may contact housing or barrel  410  at point  415 . 
     This configuration provides at least two electrical paths from tip  422  of plunger  420  to tail  412  of housing  410 . Specifically, current may flow from tip  422  to point  428  of plunger  420  to point  418  of housing  410 , then to tail  412 . Current may also flow from tip  422  to point  425  on plunger  420 , then to point  415  on barrel  410 , then to tail  412 . Depending on the exact geometries and relative position of these components, some or all of these or other electrical paths may be formed as plunger  420  is depressed relative to barrel  410 . 
       FIG. 5  illustrates a portion of a spring-loaded contact according to an embodiment of the present invention. This portion of a spring-loaded contact may include sphere or spherical isolation object  540  and plunger  520 . Plunger  520  may form an electrical connection with a second contact  580 , which may be located in a connector receptacle. Plunger  520  may include an angled backside  526  and a retention guide  522 . Sphere  540  may contact angled backside  526  and retention guide  522 . 
     In various embodiments of the present invention, plunger  520  may be formed in various ways. For example, plunger  520  may be formed using a metal lathe or metalworking lathe. For example, plunger  520  may be formed using a computer numerical controlled (CNC) lathe. In other embodiments of the present invention, plunger  520  may be formed using metal injection molding, three-dimensional printing, micromachining, etching, or other technique. In various embodiments of the present invention, retention guide  522  may be formed with the rest of plunger  520  as a single unit, though in other embodiments of the present invention they may be formed separately. 
     In various embodiments of the present invention, the composition of the components of these spring-loaded contacts may vary. For example, the plunger and barrel may be brass or other copper based material, such as bronze. The plunger and barrel may further be plated, for example with gold. The spring may be formed of conductive or nonconductive material, including stainless steel, such as stainless steel  304 , or other appropriate material. For example, music wire or high-tensile steel may be used. The spring may be plated with gold, silver, or other material. The sphere or spherical isolation object may be made of various nonconductive materials, such as ceramics, plastics, or other materials. 
       FIG. 6  illustrates a plunger according to an embodiment of the present invention. In this example, plunger  620  may have a back that may have a cup-shaped surface  626  with slot  628 . Cup-shaped surface  626  may receive an isolation object, while slot  628  may receive an additional object. In a specific embodiment of the present invention, cup-shaped surface  626  may receive a spherical isolation object, while slot  628  may receive a spherical additional object. An example is shown in the following figure. 
       FIG. 7  illustrates a cutaway view of a portion of a spring-loaded contact according to an embodiment of the present invention. In this example, the actual spring has been omitted for clarity. 
     Again, plunger  720  may have a cup-shaped surface  726  for receiving an isolation object  770 . In this specific example, isolation object  770  may be spherical, though in other embodiments of the present invention, isolation object  770  may have other shapes. Isolation object  770  may be located between plunger  720  and a spring (not shown). Isolation object  770  may be nonconductive, though in other embodiments of the present invention, isolation object  770  may be conductive. 
     Cup shaped surface  726  may include slot  728  for receiving an additional object  760 . In this specific example, additional object  760  may be a second symmetrical object. Additional object  760  may be conductive, though in other embodiments of the present invention, additional object  760  may be nonconductive. 
     In this arrangement, both isolation object  770  and additional object  760  contact a back surface of plunger  720 . This provides a reliable and redundant contacting mechanism. Also in this arrangement, both additional object  760  and plunger  720  are pushed towards the outer edge and into contact with barrel  710 , thereby improving contact. This improved contact, along with the use of a nonconductive isolation object  770 , may help to protect the spring (not shown) from large currents during operation. Moreover, since at least part of one or both of the isolating object  770  or additional object  760  are located within a back portion of plunger  720 , an overall length of the spring-loaded contact may be reduced. 
     The above description of embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Thus, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.

Metadata:
Filing Date: 20150615
Publication Date: 20160830
Grant Date: 20160830
Priority Date: 20120610
Inventors: DIFONZO JOHN
MORI Shuhi
Assignee: APPLE INC
CPC Classifications: [{"code": "H01R13/2421", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R2201/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R13/2421", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R13/17", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/17", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/2421", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R2201/06", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 49715646