The invention generally relates to an electrical connector, particularly to an electrical connector configured to electrically interconnect a flat cable.
The present invention will now be described, by way of example with reference to the accompanying drawings, in which:
The present invention will now be described, by way of example with reference to the accompanying drawings, in which:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various described embodiments. However, it will be apparent to one of ordinary skill in the art that the various described embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.
According to one embodiment of the invention, an electrical connector is provided. The electrical connector includes a housing that is configured to receive a planar first substrate including an electrically conductive first circuit trace having a first contact region. The housing is further configured to receive a planar second substrate including an electrically conductive second circuit trace having a second contact region. The housing is configured to align the first contact region with the second contact region. The electrical connector also includes a force application device that is configured to apply a compressive contact force to the first and second substrates, thereby putting the first contact region in intimate compressive contact with the second contact region.
In some embodiments of the invention, the electrical connector may further include an actuating member that is configured to increase the compressive contact force applied to the first and second substrates via interaction with the force application device. The actuating member is moveable from a pre-staged position in which the actuating member does not increase the compressive contact force to a staged position in which the actuating member increases the compressive contact force.
In some embodiments of the invention, the actuating member may be sized such that the increase in the compressive contact force is within a predetermined range regardless of an overall thickness of the first substrate and the second substrate.
In some embodiments of the invention, the compressive contact force is provided only by the force application device.
In some embodiments of the invention, the force application device is disposed within the housing.
In some embodiments of the invention, the force application device may have an open box-like structure that is configured to surround the first substrate and the second substrate.
In some embodiments of the invention, the force application device is formed of a metallic material and the housing is formed of a polymeric material.
In some embodiments of the invention, the compressive contact force comprises a first compressive contact force and a second compressive contact force in opposition to the first compressive contact force. The force application device may include a first spring member that is configured to apply the first compressive contact force to the first substrate and a second spring member configured to apply the second compressive contact force to the second substrate.
In some embodiments of the invention, the actuating member is not located intermediate the first spring member and the second spring member in the pre-staged position and the actuating member is located intermediate the first spring member and the second spring member in the staged position. The actuating member may be configured to apply the second compressive contact force to the actuating member when in the staged position, thereby applying the second compressive contact force to the second substrate.
In some embodiments of the invention, the actuating member is integral with a connector position assurance device that is configured to allow movement of the actuating member from the pre-staged position to the staged position when the housing is received within and fully mated with a corresponding mating connector.
In some embodiments of the invention, the actuating member may be sized such that the second compressive contact force is within a predetermined range regardless of an overall thickness of the first substrate and the second substrate.
In some embodiments of the invention, the second spring member is located opposite the first spring member.
In some embodiments of the invention, the first spring member and the second spring member are integrally formed within the force application device.
In some embodiments of the invention, the first spring member is an arcuate first fixed beam having a first radius of curvature and the second spring member is an arcuate second fixed beam having a second radius of curvature and wherein the first radius of curvature is less than the second radius of curvature.
In some embodiments of the invention, the electrical connector includes the first substrate which is formed of a flexible material and a planar stiffening member attached to a surface of the first substrate located opposite the first contact region.
In some embodiments of the invention, the stiffening member defines an opening through the stiffening member in which the first spring member is received and through which the first spring member makes contact with the surface of the first substrate located opposite the first contact region.
In some embodiments of the invention, the stiffening member is disposed within and is attached to the housing by a latching mechanism.
In some embodiments of the invention, a rearward edge of the stiffening member defines a ridge configured to contact the housing and positions the first contact region within the housing.
In some embodiments of the invention, a forward edge of the stiffening member defines an angled lip having a maximum height at least equal to a thickness of the first substrate.
In another embodiment of the invention, an electrical connector is provided. The electrical connector includes a housing that is configured to receive a planar first substrate including an electrically conductive first circuit trace having a first contact region in a cavity defined within the housing. The housing is further configured to receive a planar second substrate including an electrically conductive second circuit trace having a second contact region in the cavity. The first contact region is configured to be aligned with the second contact region. The electrical connector also includes a force application device having a first spring member configured to apply a first compressive contact force to the first substrate and having a second spring member configured to apply the second compressive contact force to the second substrate, thereby putting the first contact region in intimate compressive contact with the second contact region.
In some embodiments of the invention, the electrical connector may further include an actuating member configured to increase the compressive contact force applied to the first and second substrates via interaction with the force application device. The actuating member is configured to be moveable from a pre-staged position in which the actuating member is not located intermediate the first spring member and the first substrate to a staged position in which in which the actuating member is located intermediate the first spring member, thereby applying the first compressive contact force to the first substrate.
In some embodiments of the invention, the actuating member is configured to increase the second compressive contact force applied by the second spring member to the second substrate when the actuating member is in the staged position.
In some embodiments of the invention, the actuating member is sized such that the second compressive contact force applied to the second substrate is within a predetermined range regardless of an overall thickness of the first substrate and the second substrate.
In some embodiments of the invention, the actuating member is sized such that the first compressive contact force applied to the first substrate is within a predetermined range when the actuating member is in the staged position regardless of an overall thickness of the first substrate and the second substrate.
In some embodiments of the invention, the first and second compressive contact forces are provided only by the force application device.
In some embodiments of the invention, the force application device has an open box-like structure that is configured to surround the first substrate and the second substrate.
In some embodiments of the invention, the electrical connector also includes the first substrate. The first substrate may be formed of a flexible material. The electrical connector additionally includes a planar stiffening member that is attached to a surface of the first substrate located opposite the first contact region.
According to yet another embodiment of the invention, a stiffening member configured for attachment to flat flexible electrical cable formed of a flexible planar substrate including an electrically conductive circuit trace having an exposed contact region is provided. The stiffening member includes a planar body portion and an opening through the body portion configured to allow access to a surface of the substrate opposite the contact region.
In some embodiments of the invention, the stiffening member also includes an angled lip on a forward edge of the stiffening member having a maximum height at least equal to a thickness of the substrate.
In some embodiments of the invention, the stiffening member is configured to be disposed within and is attached to a housing of an electrical connector.
In some embodiments of the invention, the stiffening member additionally includes a locking latch configured to engage a strike surface within the housing and retain the stiffening member within the housing.
In some embodiments of the invention, the stiffening member further includes a rearward edge of the stiffening member defines a ridge configured to contact a rearward surface of the housing of the electrical connector, thereby positioning the contact region within the housing.
According to one more embodiment of the invention, a printed circuit board assembly is provided. The printed circuit board assembly includes a circuit board substrate and a circuit board trace having a circuit board contact region configured to be in intimate contact with a cable contact region of a cable circuit trace contained in flat cable. The circuit board contact region defines a plurality of ridges protruding from a circuit board substrate surface.
In some embodiments of the invention, the plurality of ridges is formed on outer edges of a plurality of plated through holes in the circuit board contact region. The plurality of plated through holes may be arranged linearly in the circuit board contact region.
In some embodiments of the invention, the plurality of ridges is formed by a serpentine pattern in the circuit board trace within the circuit board contact region.
In some embodiments of the invention, the printed circuit board assembly also includes a connector housing surrounding the circuit board contact region. The connector housing is configured to receive a mating connector attached to the flat cable.
The connector 10 is configured to receive a planar first substrate, in this particular non-limiting example a flat cable 18, as best shown in
The connector 10 and flat cable 18 are configured to be received within a corresponding mating connector 26 attached to a planar second substrate, in this particular non-limiting example a printed circuit board (PCB) 28, as best shown in
As best illustrated in
Focusing now on the connector 10, the housing 12 and the retainer 16 are formed of a dielectric material, e.g. polyamide (PA, also known as nylon), polybutylene terephthalate (PBT), or another engineered polymer. As best shown in
In the non-limiting example shown in
As shown in
The open box shape of the spring array 14 is configured such that the compressive contact forces 50, 52 applied to the flat cable 18 and PCB 28 are supplied solely by the spring array 14. The spring array 14 is free floating within the housing 12 such that the housing 12 does not provide any of the compressive contact force to the flat cable 18 or the PCB 28. The inventors have found that the open sheet metal box of the spring array 14 diminishes a reduction in compressive contact forces 50, 52 that may occur over time or with exposure to elevated temperatures, e.g. temperatures exceeding 85° C. due to relaxation when a polymeric element, such as the housing 12, provides all or a portion of the compressive contact forces 50, 54.
As best shown in
Alternative embodiments of the connector may not include an actuating member and in these embodiments the top spring member may be in direct contact with the PCB. In these embodiments it may be preferred to have an electrically insulative surface of the PCB in contact with the top spring member or to have an electrical insulative member between the top spring member and the PCB to avoid electrical short circuiting of conductive traces on the PCB. Additionally, alternative embodiments of the connector may include top and bottom spring members that are cantilevered springs, coil springs, elliptical springs, or other types of compression springs. In applications where polymeric creep or relaxation are not a design factor, the spring array may be formed of a polymeric material since the spring array is not a current carrying member and or may not be a separate open box design but may be integrated into the housing.
A best shown in
Focusing now on the flat cable 18 as illustrated in
The flat cable 18 also includes a stiffening member 24 that is attached to an end of the flat cable 18 on a side of the flat cable 18 located opposite the first contact regions 22. The stiffening member 24 may be attached to the flat cable 18 using a pressure bond adhesive (not shown), such as VHB™ double sided adhesive tape manufactured by the 3M Corporation of Minneapolis, Minn. The stiffening member 24 is formed of a dielectric material, such as PA or PBT and includes a planar body portion 68 and a plurality of openings 70 extending through the body portion and configured to allow contact on the surface of the flat cable 18 opposite the first contact regions 22 by the bottom spring members 46.
The stiffening member 24 includes an angled lip 72 on a forward edge of the stiffening member 24 that has a maximum height that is at least equal to a thickness of the flat cable 18. This angled lip 72 is configured to protect the flat cable 18 as the flat cable 18 and stiffening member 24 are inserted within the cavity 42 and spring array 14. The stiffening member 24 additionally includes a locking latch 74 configured to engage a strike surface 76 within the cavity 42 of the housing 12. Without subscribing to any particular theory of operation, as the stiffening member 24 is inserted within the cavity 42, the angled forward edge of the locking latch 74 causes the planar body to bend upwardly until the rearward edge of the locking latch 74 clears the strike surface 76 and planar body returns to its planar form, thereby engaging the rearward edge of the locking latch 74 with the strike surface 76. The locking latch 74 and strike surface 76 cooperate to retain the stiffening member 24 within the housing 12. A rearward edge stiffening member 24 of the stiffening member 24 defines a ridge 78 that is configured to contact a rearward surface 80 of the housing 12 of the electrical connector 10, thereby positioning the stiffening member 24 within the housing 12. As best shown in
Focusing now on the PCB 28 as shown in
The PCB 28 may use a circuit board substrate 82 that is formed of epoxy or polyimide resins. The resin may be reinforced with a woven glass cloth or other matrix such as chopped fibers. Substrates formed of such materials are typically referred to as FR-4 or G-10 type circuit boards. The PCB 28 may alternatively be constructed of ceramic or rigid polymer materials. This listing of acceptable substrate materials is not exhaustive and other materials may also be used successfully. A layer of conductive material, such as a copper based material is electroplated on at least one major surface of the PCB 28. The layer of conductive material is then formed to create the second conductive traces 30 and second contact regions 32 typically by using a chemical etching process.
In some embodiments of the invention, the plurality of ridges 84 is formed on outer edges of a plurality of plated through holes or vias 86 in the second contact region 32 as shown in
Each via 86 consists of two pads in corresponding positions on different layers of the substrate 82 that are electrically connected by a hole through the board. The hole is made conductive by electroplating. The electroplating is thickest on the outside edge of the pad and is tapered in thickness as it approaches the hole, thereby forming an “inverted volcano” shape. The pad on one or both sides of the PCB 28 is connected to the second conductive traces 30 on the surface of the PCB 28. The second conductive traces 30 interconnect each of the second contact regions 32 to electrical components on the PCB 28. The materials and manufacturing techniques used to the form PCBs and vias are well known to those skilled in the art.
In other embodiments of the invention, the plurality of ridges 84 is formed by a serpentine pattern 88 in the second conductive traces 30 within the second contact region 32 as shown in
The printed circuit board also includes the mating connector 26 which defines a shroud 90 surrounding the second contact region 32 that is configured to receive a forward portion of the housing 12 of the connector 10. The connector 10 and the mating connector 26 cooperate to align the first contact regions 22 with the second contact regions 32.
While the examples of the connector 10 described herein is configured to connect a flat cable 18 with a PCB 28, other embodiments of the connector may be envisioned in which the connector is configured to interconnect one flat cable with another flat cable to make an in-line connection.
Additionally, while the connector 10 described herein is configured to connect a single flat cable 18 with a pcb 28, other embodiments of the connector may be envisioned in which the connector is configured to interconnect two flat cables with the PCB; one flat cable connected to each side of the PCB.
Further, while the connector 10 described herein includes an actuating member 40 that is integrated with a CPA device 34. Other embodiments of the invention may be envisioned in which the actuating member is implemented without a CPA device.
Accordingly, an electrical connector 10 is presented. The connector provides a zero insertion force (ZIF) connection between a flat cable 18 and a PCB 28, another flat cable, or any other flat substrate having suitably aligned contact regions while providing a high contact force after the actuating member 40 moved to the staged position 38. The connector 10 also provides reduced wiping forces between the first and second contact regions 22, 32 as the connector 10 and the mating connector 26 are attached to one another. The thickness of the actuating member 40 may be adjusted to accommodate different thicknesses of the flat cable(s), PCB, or other substrate without having to make changes to the housing 12, retainer 16, or the spring array 14 of the connector 10. The actuating member 40 and the spring array 14 cooperate to beneficially provide a uniform compressive contact pressure on each pair of first and second contact regions 22, 32. Additionally, the ridges 84 formed in the second contact regions 32 create stress concentrations that increase the reliability and current carrying capacity of the connection between the first contact regions 22 and the second contact regions 32.
While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to configure a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely prototypical embodiments.
Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the following claims, along with the full scope of equivalents to which such claims are entitled.
As used herein, ‘one or more’ includes a function being performed by one element, a function being performed by more than one element, e.g., in a distributed fashion, several functions being performed by one element, several functions being performed by several elements, or any combination of the above.
It will also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first contact could be termed a second contact, and, similarly, a second contact could be termed a first contact, without departing from the scope of the various described embodiments. The first contact and the second contact are both contacts, but they are not the same contact.
The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various described embodiments and the appended claims, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
As used herein, the term “if” is, optionally, construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” is, optionally, construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context.
Additionally, while terms of ordinance or orientation may be used herein these elements should not be limited by these terms. All terms of ordinance or orientation, unless stated otherwise, are used for purposes distinguishing one element from another, and do not denote any particular order, order of operations, direction or orientation unless stated otherwise.
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