The present invention relates to electrical contacts, in particular to high-reliability miniature electrical contacts.
An electrical connection can be made between two electrical devices, usually using a male and female electrical contact. One part of the connection has a male contact with an electrical pin and the other part is a female contact in the form of a socket for receiving the male contact.
Known female contacts include a female contact formed of a cylindrical base, the base having a stamped four finger clip inserted into one end. Examples of such known contacts are those of the Datamate and Micro D range that are manufactured by Harwin PLC. One problem with this type of contact is that, on a miniature scale, it is difficult to form the base and clip because these must be formed of very thin material that will not have the mechanical strength required to survive the insertion of the clip into the base. This problem is a significant barrier in the design and manufacture of complex miniature scale electrical contacts. In the present specification the term ‘miniature’ should be understood to mean length scales of the order of approximately a tenth of a millimeter up to a centimeter or so.
GB 2501063 A discloses a method of manufacturing a female electrical contact from a single piece of material by removal of material from the piece of material by machining, the removal of material comprising the steps of: forming at least one first hole in a first end of the material to form a contact portion, the at least one first hole formed along a longitudinal axis X of the material; making at least two slits in the contact portion to produce contact fingers, the slits extending from the first end along at least a portion of length of the contact portion. A corresponding single piece female contact is provided.
The present invention provides a female contact comprising a body portion and a contact portion that is distal to the body portion. The contact portion comprises a plurality of fingers tapered towards the longitudinal axis of the contact, and slots located between adjacent fingers. The tapering of the plurality of fingers of the contact portion may be uniform; however this is not a requirement. The contact portion further comprises a tip portion at an end that is distal to the body portion. At least one of the plurality of fingers of the contact portion bends outwards at the tip portion, away from the longitudinal axis of the contact. Some or all the fingers of the contact portion may bend outwards at their respective tip portions, away from the longitudinal axis of the contact. The tip portion in this invention acts to provide additional contact force for greater shock and vibration resistance.
In some cases, irrespective of the configuration of the contact, the female contact further comprises a protrusion located on the outer surface of the contact. Optionally, this protrusion can extend around the entire circumference of the contact. The contact can be configured such that the slots extend beyond the protrusion of the contact.
In some cases, irrespective of the configuration of the contact, a first hole is provided by the contact portion. Additionally, in some cases, at least one second hole is provided in the end of the piece of material that is distal to the contact portion. Optionally, the contact can include a through hole connecting the first and at least second holes to form a channel through the interior of the contact. A through hole can assist with the plating process and can allow the plating to completely cover the inside of the contact.
In some cases, irrespective of the configuration of the contact, at least a part of the contact can be plated. Optionally, the plating can include at least one of gold and nickel.
In some cases, irrespective of the configuration of the contact, a plurality of said contacts can be comprised within an insulating housing comprising a plurality of holes for the insertion of said plurality of contacts. In particular, from an aspect of the invention, an electrical connector is provided, comprising an insulating housing and at least one hole, wherein the aforementioned electrical contact is located within the at least one hole. In some cases, there may be a plurality of holes and one or more of the holes may be provided with the aforementioned contact.
Embodiments of the present invention are now described, by way of example only, with reference to the accompanying drawings, in which:
A miniature female contact 100 according to the first embodiment will now be described with reference to
Contact 100 will be described herein in terms of a body portion 112 and a contact portion 114. Preferably contact 100 is formed of electrically conductive material such as beryllium copper, but other suitable materials known to the skilled person may be used.
Body portion 112 is substantially cylindrical and includes a barrel 116 that is centred on the longitudinal axis X of body portion 112. Barrel 116 is open at one end, this end being distal contact portion 114, to allow access to its interior. The interior surface of barrel 116 is contoured to form a receptacle. For ease of description the receptacle will be described in terms of two portions; a receptacle outer portion 118a and a receptacle inner portion 118b, although it should be understood that no gaps, breaks, interfaces or discontinuities are present between receptacle outer portion 118a and receptacle inner portion 118b.
Receptacle outer portion 118a is adjacent the open end of barrel 116 and receptacle inner portion 118b is adjacent receptacle outer portion 118a and is thus wholly contained within barrel 116. In the present embodiment the interior surface of barrel 116 is contoured such both receptacle outer portion 118a and receptacle inner portion 118b have a substantially cylindrical cross-section, with the diameter of receptacle outer portion 118a being larger than the diameter of receptacle inner portion 118b. In the present embodiment receptacle outer portion 118a is shorter in axial length than receptacle inner portion 118b.
The profile of the interior surface of barrel 116 allows a wire (not shown) to be received in the interior of barrel 116 via its open end. The wire is fed into receptacle outer portion 118a and receptacle inner portion 118b. Preferably a stripped (non-insulated) portion of the wire is positioned in receptacle inner portion 118b and a covered (insulated) portion of the wire is positioned in receptacle outer portion 118a. Arrangement of the wire in this manner advantageously allows the receptacle to act as a strain relief system for the wire.
Once the wire is in place, substantially uniform force is applied along and around the portion of the outer surface of barrel 116 that is aligned with receptacle inner portion 118b. This causes receptacle inner portion 118b to compress and in doing so secures the stripped portion of the wire in barrel 116 and ensures that a good electrical connection is made. This compression (or crimping) may be achieved using any tool known by the skilled person that is appropriate for the task, such as an 8 point indentation tool.
It should be understood that the interior profile of barrel 116 described above is purely exemplary and the interior of barrel 116 may define any other profile that is suitable for receiving a wire.
As mentioned earlier body portion 112 is substantially cylindrical. However a recessed portion 119 is located in the outer surface of body portion 112 at the end of body portion 112 that is proximate contact portion 114. Recessed portion 119 has a protrusion 119a along part of its length, with both recessed portion 119 and protrusion 119a being positioned to align with complimentary features in a housing (described later) in which contact 100 is secured. In the present embodiment protrusion 119a extends around the entire circumference of body portion 112.
In the interior of body portion 112 and adjacent receptacle inner portion 118b is a through hole 120. Adjacent through hole 120 is a drilled cavity 122. Both through hole 120 and drilled cavity 122 are centred on the longitudinal axis X of body portion 112. Like receptacles 118a and 118b, the extents of through hole 120 and drilled cavity 122 are defined by the contours of the inner surface of body portion 112 so as to form a channel 121 through the interior of the contact. In the present embodiment through hole 120 and drilled cavity 122 both have a substantially cylindrical shape, although other shapes may be used for either feature.
Through hole 120 has a diameter smaller than that of receptacle inner portion 118b, although other cross-sectional profiles and diameters may be used. The shape and dimensions of drilled cavity 122 are selected to allow a male pin (not shown) to fit snugly and securely within it. There are no gaps, breaks, interfaces or discontinuities in the portion of the interior surface of body portion 112 that defines receptacle inner portion 118b and through hole 120, and similarly no gaps, breaks, interfaces or discontinuities in the portion of the interior surface that defines through hole 120 and drilled cavity 122.
Through hole 120 and drilled cavity 122 allow access to the interior of body portion 112 (and consequently barrel 116) from the end of body portion 112 that is proximate contact portion 114. This is so that, in use, a male pin sits within contact portion 114, drilled cavity 122 and through hole 120 and is in electrical contact with the wire (not shown) via the stripped portion of the wire that is housed in receptacle inner portion 118b.
Through hole 120 is provided to allow at least some of and typically substantially all of the entire internal surface of body 112 to be plated, which improves the electrical contact between a male pin and contact 100 when in use. Known contacts use blind holes for this purpose which typically provide poor plating coverage at best. The provision of through hole 120 therefore improves the plating coverage of the interior surface of body 112 and consequently improves the reliability of contact 100. Preferably the plating comprises a nickel undercoat and a gold topcoat, but other platings known to the skilled person can be used.
Turning now to contact portion 114, in the present embodiment this comprises six fingers 124a, 124b, 124c, 124d, 124e and 124f (only two of which are shown in
Finger 124a is formed of a sheet of material that extends away from the end of body portion 112 that contains drilled cavity 122. The finger 124a is formed into a sheet of material or any other shape through machining of a rod rather than being formed from a sheet that has been rolled for example. In the present embodiment finger 124a has the profile of a hollow frustum of a cone that has been cut into sixths along the length of its longitudinal axis X, where the longitudinal axis X of the frustum is aligned with the longitudinal axis X of body portion 112. Finger 124a is at an angle relative to the longitudinal axis of body portion 112, such that finger 124a converges towards this longitudinal axis X when moving from the base of finger 124a (the base of finger 124a being joined to body portion 112) towards the tip portion 128 of finger 124a.
The tip portion 128 is located at the end of finger 124a that is distal the body portion 112, and in the present embodiment, comprises a curved or angled portion that extends away from the longitudinal axis X of the body portion 112, creating a larger diameter at the end of the tip portion 128, relative to where the tip portion 128 begins on the contact portion 114. This characteristic results in a tip portion 128 with the profile of a hollow frustum of a cone that has been cut into sixths along the length of its longitudinal axis X, the tip portion 128 being located at the end of the contact portion 114, wherein one end of the tip portion having the smaller diameter meets the point where the diameter of the contact portion 114 is at its smallest. Tip portion 128 acts as a lead in or guide for a male pin (not shown) during mating, such that the male pin is more easily and readily inserted into contact portion 114. Furthermore, the outwardly flared tip portion 128 can be prevented from entering receptacle portions 118a, 118b of another similar contact and becoming interlocked when, for example, multiple contacts are being processing in high quantity during various manufacturing processes such as gold plating. It will therefore be apparent from the above that the contact portion 114 has fingers 124 that taper inwards towards the central longitudinal axis X and then taper outwards in the tip portion 128. The inner profile (surface) of the fingers mirrors the outer profile (outer surface) of the fingers such that they are substantially parallel. It will be appreciated that in an alternative embodiment, the inner profile may continue tapering inwards or substantially inwards toward the longitudinal axis whilst the outer profile tapers outwards resulting in an alternative tip portion (not shown). As is apparent from the above, the construction of in this embodiment can be achieved by manufacturing the fingers 124 from machined rod metal, as opposed to the commonly used sheet metal manufacturing process. This feature can allow the inside diameter of the contact portion 114 to have an independent profile or shape to that of the outside diameter across the length of the fingers 114. The non-parallel inside and outside surfaces of the fingers 124 allows the inside surface to have an optimum lead in for a mating pin, whilst allowing the outside diameter to increase at the tip portion 128. In either embodiment, only a relatively small part of one end of the contact portion forms the tip portion.
The increased diameter tip portion 128 (i.e. diameter D viewed from the contact portion end where the tip portion 128 is located) which has fingers diverging away from the longitudinal axis X can help prevent the contact portion 114 from entering into receptacle 118b. The end of the contact 100 where the tip portion 128 is located has a relatively large diameter compared to the diameter of the receptacle 118b. The tip portion 128 diverges away from the central longitudinal axis X after a location A where the contact portion has converged and, given the outer profile of the tip portion also diverges away, it is difficult or not possible for the contact to enter the receptacle 118b. This arrangement is useful when, for example, processing multiple contacts for plating or assembly where multiple contacts are collected in a container. Without this increased diameter tip portion, the contact portion may enter receptacles 118a and 118b which results in the undesirable locking together of contacts that can prevent correct plating of products and assembly problems. These problems can be addressed with the tip portion 128.
The tip portion 128 can also be used to retain various types of springs or ‘0’ rings on the contact 100. These springs can be used to increase the contact force by variable amounts to improve both contact resistance and shock and vibration performance. In particular, location A of the contact portion with a reduced diameter (as explained above where one end of the tip portion 128 having the smaller diameter meets the point where the diameter of the contact portion 114 is at its smallest) can receive at least one spring and/or ‘0’ ring (not shown) which can increase the force provided radially inwards at the reduced diameter area.
In use, a male pin (not shown) is inserted within the cavity defined by fingers 124a, 124b . . . and is held in position by these fingers.
Contact 500 will be described herein in terms of a body portion 512 and a contact portion 514. The body portion 512 is similar to the body portion of 112 of
Body portion 512 is substantially cylindrical and includes a barrel 516 that is centred on the longitudinal axis X of body portion 512. Barrel 516 is open at one end, this end being distal contact portion 514, to allow access to its interior. The interior surface of barrel 516 is contoured to form a receptacle. For ease of description the receptacle will be described in terms of two portions; a receptacle outer portion 518a and a receptacle inner portion 518b, although it should be understood that no gaps, breaks, interfaces or discontinuities are present between receptacle outer portion 518a and receptacle inner portion 518b.
Receptacle outer portion 518a is adjacent the open end of barrel 516 and receptacle inner portion 518b is adjacent receptacle outer portion 518a and is thus wholly contained within barrel 516. In the present embodiment the interior surface of barrel 516 is contoured such both receptacle outer portion 518a and receptacle inner portion 518b have a substantially cylindrical cross-section, with the diameter of receptacle outer portion 518a being larger than the diameter of receptacle inner portion 518b. In the present embodiment receptacle outer portion 518a is shorter in axial length than receptacle inner portion 518b.
The profile of the interior surface of barrel 516 allows a wire (not shown) to be received in the interior of barrel 516 via its open end. The wire is fed into receptacle outer portion 518a and receptacle inner portion 518b. Preferably a stripped (non-insulated) portion of the wire is positioned in receptacle inner portion 518b and a covered (insulated) portion of the wire is positioned in receptacle outer portion 518a. Arrangement of the wire in this manner advantageously allows the receptacle to act as a strain relief system for the wire.
Once the wire is in place, substantially uniform force is applied along and around the portion of the outer surface of barrel 516 that is aligned with receptacle inner portion 518b. This causes receptacle inner portion 518b to compress and in doing so secures the stripped portion of the wire in barrel 516 and ensures that a good electrical connection is made. This compression (or crimping) may be achieved using any tool known by the skilled person that is appropriate for the task, such as an 8 point indentation tool.
It should be understood that the interior profile of barrel 516 described above is purely exemplary and the interior of barrel 516 may define any other profile that is suitable for receiving a wire.
As mentioned earlier, body portion 512 is substantially cylindrical. However the recessed portion 519 is located in the outer surface of body portion 512 at the end of body portion 512 that is proximate contact portion 514. Recessed portion 519 has a protrusion 519a along part of its length, with both recessed portion 519 and protrusion 519a being positioned to align with complimentary features in a housing (described later) in which contact 500 is secured. In the present embodiment protrusion 519a extends around the circumference of body portion 512 with the plurality of slots 525a-f forming multiple spaces in the protrusion 519a.
In the interior of body portion 512 and adjacent receptacle inner portion 518b is a through hole 520. Adjacent through hole 520 is a drilled cavity 522. Both through hole 520 and drilled cavity 522 are centred on the longitudinal axis X of body portion 512. Like receptacles 518a and 518b, the extents of through hole 520 and drilled cavity 522 are defined by the contours of the inner surface of body portion 512 so as to form a channel 521 through the interior of the contact. In the present embodiment through hole 520 and drilled cavity 522 both have a substantially cylindrical shape, although other shapes may be used for either feature.
Similarly to the equivalent features (120, 118b) of
Through hole 520 and drilled cavity 522 allow access to the interior of body portion 512 (and consequently barrel 516) from the end of body portion 512 that is proximate contact portion 514. This is so that, in use, a male pin sits within contact portion 514, drilled cavity 522 and through hole 520 and is in electrical contact with the wire (not shown) via the stripped portion of the wire that is housed in receptacle inner portion 518b.
Through hole 520 is provided to allow at least some of and typically substantially all of the entire internal surface of body 512 to be plated, which improves the electrical contact between a male pin and contact 500 when in use. Known contacts use blind holes for this purpose which typically provide poor plating coverage at best. The provision of through hole 520 therefore improves the plating coverage of the interior surface of body 512 and consequently improves the reliability of contact 500. Preferably the plating comprises a nickel undercoat and a gold topcoat, but other platings known to the skilled person can be used.
Turning now to contact portion 514, in the present embodiment this comprises six fingers 524a, 524b, 524c, 524d, 524e and 524f (only two of which are shown in
As mentioned above, differently to the first embodiment, fingers 524a, 524b, 524c, 524d, 524e and 524f extend beyond the protrusion 519a and into the recessed portion 519 of the contact 500. This provides advantages relating to compliance of the contact.
Finger 524a is formed of a sheet of material that extends away from near one end of recessed portion 519 that contains drilled cavity 522 and adjacent the barrel 516. The finger 524a is formed into a sheet of material or any other shape through machining of a rod rather than being formed from a sheet that has been rolled for example. In the present embodiment finger 524a has the profile of a linear portion 519b (see
The tip portion 528 is located at the end of finger 524a that is distal the body portion 512, and in the present embodiment, comprises a curved portion that extends away from the longitudinal axis X of the body portion 512, creating a larger diameter at the end of the tip portion 528, relative to where the tip portion 528 begins on the contact portion 514. This characteristic results in a tip portion 528 with the profile of a hollow frustum of a cone that has been cut into sixths along the length of its longitudinal axis X, the tip portion 528 being located at the end of the contact portion 514, wherein one end of the tip portion having the smaller diameter meets the point where the diameter of the contact portion 514 is at its smallest. Tip portion 528 can act as a lead in or guide for a male pin (not shown) during mating, such that the male pin is more easily and readily inserted into contact portion 514. It will therefore be apparent from the above that the contact portion 514 has fingers 524 that taper inwards towards the central longitudinal axis X and then taper outwards in the tip portion 528. An inner profile or inner surface 529 of the fingers mirrors an outer profile or outer surface 530 of the fingers such that they are substantially parallel. It will be appreciated that in an alternative embodiment, shown in
In use, a male pin (not shown) is inserted within the cavity defined by fingers 524a, 524b . . . and is held in position by these fingers.
The problems regarding undesirable locking together of contacts that can prevent correct plating of products and assembly problems as overcome with the contact 100 as mentioned in relation to the first embodiment is also addressed by the contact 500 and tip portion 528 of this embodiment. Further, the increased forces provided by locating springs or ‘0’ rings on the contact 100 are also achieved with the contact 500. The description is not repeated here for brevity but the function and advantages of tip portion 528 would be understood by the skilled person through reference to the first embodiment.
Benefits that may be provided by one or more of the embodiments are that: 1) the profile tip 128/528 can provide increased contact force for improved shock and vibration performance; 2) the profile tip 128/528 can prevent compliant section being over stressed (damaged); 3) the profile tip 128/528 can prevent multiple parts in a container becoming locked together by tip 128/528 entering hole 118b/518b; 4) extended slots 525a make retention feature 519a compliant when assembled through step 930, thereby reducing assembly forces and chances of damage to 930, and increasing number of times contact can be replaced in housing; 5) the tip portion 128 can also be used to retain various types of springs or ‘0’ rings on the contact. These springs can be used to increase the contact force by variable amounts to improve both contact resistance and shock and vibration performance; 6) 6 fingers instead of 3 or 4 can increase the number of contact points, to improve power, shock and vibration specification of contact.
Numerous modifications, adaptations and variations to the embodiments described herein will become apparent to a person skilled in the art having the benefit of the present disclosure, and such modifications, adaptations and variations that result in additional embodiments of the present invention are also within the scope of the accompanying claims.
In addition to the claimed embodiments in the appended claims, the following is a list of additional embodiments which may serve as the basis for additional claims in this application or subsequent divisional applications:
A female electrical contact comprising;
The contact of embodiment 1, wherein some or all of the plurality of fingers bend outwards at the tip portion away from the longitudinal axis of the contact.
The contact of embodiment 1, wherein the tapering is uniform.
The contact of any preceding embodiment, further comprising a protrusion located on the outer surface of the contact.
The contact of embodiment, wherein the protrusion extends around the entire circumference of the contact.
The contact of any preceding embodiment, wherein a first hole is provided in the contact portion.
The contact of embodiment 6, wherein at least one second hole is provided in the end of the piece of material that is distal the contact portion.
The contact of embodiment 7, wherein the contact includes a through hole, the through hole connecting the first and at least second holes to form a channel through the interior of the contact.
The contact of any preceding embodiment, wherein at least a part of the contact is plated.
The contact of embodiment 9, wherein the plating includes at least one of gold and nickel.
The contact of any one of embodiments 4 or 5, wherein at least one slot extends beyond the protrusion of the contact.
The contact of any preceding embodiment, wherein the plurality of fingers comprises at least six fingers.
An electrical connector comprising an insulating housing and at least one hole, wherein the electrical contact of any preceding embodiment is located within the at least one hole.
The electrical connector of embodiment 12, wherein the electrical connector comprises a plurality of holes and one or more of the holes is provided with the electrical contact.
Number | Date | Country | Kind |
---|---|---|---|
1616011.1 | Sep 2016 | GB | national |
Number | Name | Date | Kind |
---|---|---|---|
2689337 | Burtt et al. | Sep 1954 | A |
4728304 | Fischer | Mar 1988 | A |
5067916 | Denlinger | Nov 1991 | A |
5376012 | Clark | Dec 1994 | A |
5775960 | Saito | Jul 1998 | A |
5938487 | Henry et al. | Aug 1999 | A |
7497742 | Spinnato | Mar 2009 | B2 |
8782883 | Shimizu | Jul 2014 | B2 |
8821196 | Blasick et al. | Sep 2014 | B2 |
8851940 | Friedhof et al. | Oct 2014 | B2 |
9017089 | Flower | Apr 2015 | B2 |
9325095 | Glick | Apr 2016 | B2 |
9640890 | Ito | May 2017 | B2 |
20130225015 | Blasick et al. | Aug 2013 | A1 |
20130337702 | Pavlovic | Dec 2013 | A1 |
Number | Date | Country |
---|---|---|
0 261 778 | Aug 1987 | EP |
1 868 266 | Dec 2007 | EP |
2501063 | Oct 2013 | GB |
WO 9815036 | Apr 1998 | WO |
WO 2014116338 | Jul 2014 | WO |
Entry |
---|
UK Search Report dated Feb. 1, 2017 in related application GB1616011.1. |
European Search Report dated Feb. 16, 2018 in related application No. 17191788.3. |
European Search Report dated Oct. 22, 2018 in related application No. 17191788.3. |
Number | Date | Country | |
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20180083378 A1 | Mar 2018 | US |