Patent Publication Number: US-8113860-B2

Title: High power multi-pin electrical connector

Description:
FIELD OF THE INVENTION 
     The invention relates to a multi-pin electrical connector, and more particularly to such a connector that is suitable for use in a wet environment. 
     BACKGROUND OF THE INVENTION 
     Multi-pin electrical connectors are commonly used in a broad range of industrial applications, including medical equipment, factory automation, heavy equipment, instrumentation, motion control, rail mass transportation, and natural resource exploration. The typical multi-pin connector has a set of pins on one half of the connector (the male part) and a set of mating sockets in the other half of the connector (the female part). Generally, each pin and socket combination is used for a separate electrical circuit while all of the pin/socket sets are contained in a common connector shell. This allows all pins to be connected or disconnected at the same time, allowing ease of use and ensuring that each pin is correctly mated to its matching socket. The pins are closely spaced in order to fit within a single shell. This design is beneficial because it reduces the size and weight of the connector. 
     There are, however, problems when multi-pin connectors are used in wet environments. This can occur in many industrial settings. In natural resource exploration and removal (e.g., in the oilfield industry), it is not unusual to be operating in wet conditions. Other situation may also involve wet conditions at times. Outdoor entertainment, events like concerts or fairs, will sometimes experience wet conditions. Some manufacturing is done in wet conditions. Vehicles, from motorcycles to locomotives to ships all operate in wet conditions. 
     When a multi-pin connector is used in a wet environment, there is a risk that water will enter the connector and effectively create new electrical flow paths within the connector. These connectors have multiple electrical connections close together, with each line carrying a separate signal that needs to remain isolated from other signals. When water makes contact with more than one set of connections, cross-talk between the two signals may occur. Signal deterioration or even complete signal loss can result. The water becomes a new circuit within the connector and effectively interconnects signals that must remain isolated for proper operation. 
     Depending upon the use of the connector, this type of problem can have catastrophic consequences. Control signals could be lost and certain equipment may malfunction as a result. Loss of property, injury to workers, and economic loss due to down time may follow. If a multi-pin connector on a locomotive fails due to wet conditions, the train might miss a signal to change tracks and collide with another train. In almost any context where multi-pin connectors can be exposed to wet conditions, there is the risk of serious damage or loss if the connectors fail. 
     There is, therefore, a need for a multi-pin electrical connector that will operate in wet conditions without risk of failure. Because there are a number of ways that water might enter into a multi-pin connector, the improved connector would need to incorporate a number of distinct improvements. The current invention meets these needs. 
     SUMMARY OF THE INVENTION 
     The invention is an improved multi-pin connector suitable for wet conditions. When a multi-pin connector is used in wet conditions, it must be assumed that water may exist in any open space within the connector. This fact poses a significant challenge. Indeed, this fact shows that trying to design a multi-pin connector that has no water anywhere within the connector is probably an exercise in futility. 
     The current invention solves these problems by isolating all contact areas from each other. By doing so, the invention allows for the possibility that water may get into the area around the contacts before the two parts of the connection are made up. When the male and female parts are connected together, the invention uses a number of seals that create isolated pockets of water. These pockets of water cannot reach each other and connect create a path from one internal connection to another. 
     The accomplish this result, the invention uses a flexible seal around the base of each pin on the male part of the connector. The opening at the end of the female receptacle has a bevel. When the male and female are connected, the flexible seal mates with the bevel surface and provides a good seal around each female opening. The seal expands outward when the connection is made up, and thus seals the connection. Each pin/socket connection is sealed in this way. 
     The invention also uses seals at the back of each part of the connector. Wires exit from the back of both parts of the connector. A flexible seal is used inside the wire openings to seal the wires to the insulator body. In addition, the invention uses an overmolding process to bond the different insulator materials uses in each part of the connector. These improvements allow the connector to operate in wet conditions with minimal risk of failure. 
     The invention also uses an improved female socket. The female receptacle has a longitudinal slot so that the receptacle can slightly increase or decrease in diameter. A cylindrical spring sleeve surrounds the socket and applies a small force to slightly reduce the diameter of the socket. A male pin must slightly expand the female socket when the connection is made up. This improvement provides a wiping action, thus cleaning the surface of the male pin, which was exposed to the environment prior to making up the connection. This improvement also creates a better contact between the male and female, thus improving signal quality. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an illustration of the cross section of the male-to-female connection area of a prior art connector and  FIG. 1B  is an illustration of the cross section of the male-to-female connection area of the current invention. 
         FIG. 2  is an illustration of the cross section of the back end of a connector where the wires exit the connector.  FIG. 2A  illustrates a prior art design and  FIG. 2B  illustrates the current invention. 
         FIG. 3A  is an illustration of the cross section of the area where two different insulator materials meet within a prior art connector and  FIG. 3B  is an illustration of the cross section of the area where two different insulator materials meet within the current invention. 
         FIG. 4  is an illustration of the cross-section of the female receptacle of the present invention. 
         FIG. 5  is a cut-away illustration of part of the male component of the present invention. 
         FIG. 6  is a much enlarged version of a portion of  FIG. 5 . 
         FIG. 7  is a cut-away illustration of part of the female component of the present invention. 
         FIG. 8  is a cut-away illustration of the male-to-female interconnection of the present invention. 
         FIG. 9  is a cut-away of the full length (i.e., with male and female components connected) of the internal part of a connector made in accordance with the present invention. 
         FIG. 10  is a cut-away of a connector of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The problem water poses to multi-pin connectors is due to the electrical conductivity of the water and the numerous electrical contacts in close proximity to each other. The conductivity of water varies depending upon how many other substances are in the water. Pure water is a very poor conductor. But the water found in most industrial environments (e.g., sea water, rain, tap water, etc.) is a good enough conductor to pose problems. 
     A multi-pin electrical connector requires complete electrical isolation of each separate electrical line within the connector. Every pin and receptacle pair must be electrically isolated from all other pins and receptacles. If a continuous path of water exists between a conductor of one line and a conductor of another line, the water may form an electrical connection between the two conductors. This unintended and undesirable cross-connection between electrical contacts carrying separate signals creates cross talk. 
     The problem posed by cross talk varies depending upon the nature of the signals and the conductivity of the electrical path between the separate signal lines. When the conductivity between the conductors of the separate signals is low, the cross talk is low and may not pose significant problems. But when the conductivity is relatively high, cross talk can result in complete loss of a signal, extreme interference between signals, or spurious signals. As explained above, these situations can lead to catastrophic results. 
     The first three figures illustrate three ways water can lead to cross talk in a multi-pin connector.  FIGS. 1A and 1B  illustrates the point of connection of the male component  12  and female component  14  of a multi-pin electrical conductor  10 . When the two components are connected together, pins  16  are inserted into receptacles  18 . As  FIGS. 1A and 1B  illustrates, the male contact end  24  and the female contact end  26  do not actually come into contact with each other when the connector is made up. Various factors contribute to this result, including manufacturing tolerances and, in some instances, debris. 
     As a result, a small gap exists between the male contact end  24  and the female contact end  26 , and water  20  may remain in this gap. This water  20  will be in physical and electrical contact with the pins  16  and, in some instances, with receptacles  18 , as well, as shown in  FIG. 1A . The water  20 , therefore, may create an unintended and undesired electrical connection between pins, between receptacles, or combinations of the two, thus causing cross talk in the prior art connector shown in  FIG. 1A . 
     The present invention solves this problem. The base of the pins  16  are surrounded by flexible seals  30 , as shown in  FIG. 1B . When the male component  12  and female component  14  are pushed together, the flexible seals  30  are deformed radially outward as illustrated in  FIG. 1B . There are beveled openings  32  on the female contact end  26  where the pins  16  enter the female component  14 . The base end of each flexible seal  30  is connected to the male contact end  24  and the other end seats against the beveled openings  32 , thus completely sealing off every pin  16  when the connection is made up. 
     The present invention does not keep water out of the multi-pin connector  10 . Instead, the invention isolates the water in two ways. First, any water  20  remaining in the small gap between the male contact end  24  and the female contact end  26  is isolated from the pins  16 , thus preventing cross talk due to such water. Second, it is possible for very small pockets of water  20  to remain trapped in the area around the pins  16  and receptacles  18 . This too is illustrated in  FIG. 1B . Such small pockets of water are isolated to each pin/receptacle contact area, and therefore, cannot complete an electrical connection to any other pin/receptacle pair. In this manner, the present invention prevents water in the contact area from causing cross talk. 
       FIGS. 2A and 2B  illustrates a second way that water can lead to cross talk. In these drawings, a first cable end  34  of a male component  12  is illustrated. Wires  26  are shown exiting the connector. These wires typically are grouped into a cable that extends from the end of the connector. When a connector of this type is used in a wet environment, water  20  may enter the area around the wires  26  and may reach the connection between the wires  26  and either the pins  16  (i.e., for a male component  12 ) or the receptacles (i.e., for a female component  14 ). If water  20  reaches the electrical contacts of two or more lines, an electrical connection may be created, thus causing cross talk, as shown in  FIG. 2A . 
     The present invention solves this problem by using one or more flexible, cylindrical seals  38  near the cable end  34  of the connector, as shown in  FIG. 2B . These seals  38  form a water-tight seal between the body of the connector and the wires  26 . As in the explanation above, this solution does not eliminate water  20  from the internal parts of the connector. Instead, this solution, as shown in  FIG. 2B , isolates pockets of water  20  from each other, and thus prevents such water  20  from creating electrical connections between separate lines. This isolation prevents cross talk. 
       FIGS. 3A and 3B  illustrates yet another way that water can lead to cross talk in a multi-pin connector. An internal portion of a male component  12  is illustrated, and two different insulator materials are shown where they meet. A flexible insulator  44  is shown on the right side of  FIGS. 3A and 3B , and would typically be used at the cable end  34  of the male component. A rigid insulator  46  is shown on the left side of  FIGS. 3A and 3B , and would typically be used internally in the male component. The pins  16  extend across this connection point between the two insulators. Wires  26  are shown with connections  40 , as well. 
     In prior art devices, as shown in  FIG. 3A , the two insulator pieces are not physically bonded to each other. This configuration can allow very small spaces to exist between the two insulator pieces, and water  20 , can enter such spaces, as shown in  FIG. 3A . When this happens, the water  20  may be in contact with a number of pins  16 , thus causing cross talk. 
     The present invention solves this problem by permanently bonding the different insulator pieces together, as shown in  FIG. 3B . An over molding process is used in a preferred embodiment, but the insulator pieces could be glued or bonded in other ways. The bond eliminates all gaps between the insulator pieces, as shown in  FIG. 3B , and thus eliminates the third process through which water can lead to cross talk in multi-pin connectors. 
       FIG. 4  is an illustration of certain parts of the female component  14 . The area near the female contact end  26  is shown. This part of the female component  14  is typically made of a rigid insulator  68  (such as glass-reinforced phenolic), which maintains rigidity and structural integrity. The end of a longitudinal socket  70 , with a beveled opening  32 , and a larger diameter region  72 . 
     A receptacle  18  is shown within socket  70 . A first end of the receptacle  74  is positioned near the female contact end  26 , but does not extend all the way to the beveled opening  32 . By recessing the receptacle  18  a short distance within the insulating socket  70 , safety is increased because the risk of inadvertent contact with a receptacle  18  is reduced. 
     The receptacle  18  has a longitudinal slot  76  extending from the first end  74 . Though not shown in this illustration, the slot may extend along about half the length of the receptacle  18 . The slot  76  may extend along the entire length of the receptacle  18 . For best performance it is recommended that the slot  76  extend at least as far and the pins  16  will be inserted into the receptacles  18 . 
     A cylindrical spring sleeve  78  is positioned in the larger diameter region  72  of the socket  70 . This sleeve surrounds part of the slotted portion of the receptacle  18 . The spring sleeve is biased closed, that is, it tends to try to close the gap in the sleeve, and thus squeeze the receptacle slot closed, as well. The result is that the receptacle  18  has a slightly smaller diameter that in its resting state. 
     In operation, the components illustrated in  FIG. 4  improve the electrical connection between pin  16  and receptacle  18  in two ways. First, a pin  16  must be forced into the receptacle  18  by slightly expanding the slotted part of the receptacle and the spring sleeve  78 . This action creates a wiping effect that cleans the outer surface of the pin  16 . This wiping eliminates some water and debris from the pins  16 , and allows for a cleaner connection. Second, the spring sleeve  78  applies a small force to the slotted part of the receptacle  18 , and keeps the receptacle in better physical contact with the pin  16 , which also improves the electrical connection. 
     The illustrations described above provide a helpful explanation for some of the key features of the invention. The remaining drawings show how these features may be embodied in the invention by presenting a preferred embodiment of the invention.  FIG. 5  shows a male component  12 , which has a contact end  24  where the pins  16  extend outward. The opposite end is the male cable end  34 . The flexible seals  30  are shown around the base of two pins  16  and also over the end of sockets  56  with no pins. During the assembly of the male component, the pins  16  are pushed into place within the sockets  56 .  FIG. 5 , with only two pins  16  shows a male component  12  at an early stage of the final assembly process. 
     The body of the male component  12  is made of three insulator layers. Started from the cable end  34 , a first layer of insulator material  44  is made of a flexible material (e.g., silicon). In the embodiment shown, the first insulator layer  44  is the largest (i.e., thickest) of the insulator layers. It provides for flexibility that aids in the assembly process and helps form tight seals around pins positioned within the insulator body. The middle insulator layer  46  is made of a rigid material, such as glass-reinforced phenolic. This rigid layer  46  is positioned near the contact end  24 , and thus provides substantial strength and rigidity to the pins  16 . The rigid material greatly reduces the flexibility and side-to-side motion of the pins, which is a desirable result. This rigidity facilitates mating the multiple pins  16  with their corresponding receptacles  18  of the female component  14 . In a preferred embodiment, the rigid layer  46  is thinner than the first layer of flexible insulator material  44 . 
     A thin, flexible insulator layer  48  is used on the surface of the contact end  24 , in order to provide a tight seal around the pins  16 . In a preferred embodiment, this flexible insulator layer  48  is substantially thinner than the rigid layer  46  and the first flexible insulator layer  44 . The thin, flexible insulator layer  48  is used to provide flexible material on the face of the male contact end  24 , which enhances the seal around the base of each pin  16 . 
     The three insulator layers are securely and permanently bonded to each other. A variety of bonding methods may be used, but an overmolding process is preferred. This process produces a strong chemical bond between insulator materials. The flexible seals  30  are connected to the thin, flexible insulator layer  48 . 
     Two additional features of importance are shown in  FIG. 5 . Near the cable end  34 , the sockets  56  have three flexible, cylindrical seals  38 . These seals  38  provide a water-tight seal around the wires that are later connected to the pins  16 . Three such seals  38  are shown, and two or more seals are preferred, but a single seal is also within the scope of the invention. 
     Finally, a rigid outer support ring  54  is shown around the outside of the large, flexible insulator region  44 . This ring is located near the cable end  34 , and provides additional strength to that portion of the connector. The support ring  54  may be installed after all the pins  16  are in place, and thus the large flexible insulator region  44  makes installing the pins  16  easier, and the support ring  54  then provides some additional rigidity to the insulator region  44 . This result is desirable because the more the cable end  34  flexes side-to-side, the greater the risk of water movement past the flexible cylindrical seals  38 . 
       FIG. 6  is an enlarged version of part of  FIG. 5 . The thin flexible insulator layer  48  at the contact end  24  is shown in more detail, as are the flexible seals  30  that surround the base of the pins  16 . The rigid insulator layer  46  and a small part of the large, flexible insulator region  44  are also shown. It can also been seen in  FIGS. 5 and 6  that the sockets  56  may have larger diameter sections to receive larger sections of the pins  16 . This configuration makes the pins more secure longitudinally, and thus, less likely to be pushed back into the connector during use. This configuration also enhances the seal between the body of the pins  16  and the insulator materials. In particular, the flexible first insulator layer  44  produces good internal seals against the body of the pins  16 , because the flexible material allows for a tight fit around the pins  16 . 
     Another preferred, but non-essential, feature of the male connector is shown in  FIG. 6 . The pins  16  extend outwardly from the male contact end  24 . A base section of the pins  16  can be defined as that region of the external portions of the pins that is nearest the male contact end  24 . As shown in  FIG. 6 , the base section of the pins may be tapered and may extend over approximately 20% of the external length of the pins  16 . A somewhat shorter or longer taper may be used. The tapered base region enhances the seal around the base of each pin when the male connector is fully engaged with a female connector. In addition, by allowing the rest of the pin shafts to have a slightly smaller diameter, this design makes it somewhat easier to make up the connection because the smaller diameter part of the pins is easier to insert into the corresponding female receptacles. 
     The internal sockets  56  shown in  FIGS. 5 and 6  may have regions with different diameters. In a preferred embodiment, the part of the socket near the cable end is larger in order to more easily accommodate the wire connected to the pin. In the female component, the same configuration is preferred, with the only difference being that the wire is connected to a female receptacle, rather than a male pin. A smaller diameter region may then be used within the flexible insulator layer  44 , which will enhance the seal around the shaft of a pin. A larger diameter region may be used at the point where the flexible layer  44  meets and is bonded to the rigid layer  46 . This allows a correspondingly larger diameter part of the pin to seat firmly against the rigid insulator material  46  and tightly seal against the flexible insulator material  44 . The larger diameter part of the pin may be pushed through the smaller diameter portion of the socket  56  because that portion is within the flexible insulator layer  44 , which is sufficiently flexible to allow a slightly larger diameter portion of the pin to be forced through. The rigid material  46 , on the other hand, will not allow the larger diameter part of the pin to be pushed through. The combination of different flexibility insulators and the varied diameter socket or pin/receptacle arrangement allows for a secure, sealed fit between the internal parts of the electrical contact (either pin or receptacle) and the insulator body. 
       FIG. 7  shows a cut-away part of a female component  14 . Only a rigid insulator region  68  is shown, but the full female component  14  has a flexible insulator region at its cable end, similar to the configuration of the male cable end region explained above. Longitudinal sockets  70  run through the length of the female component  14 . A larger diameter region  72  is shown starting somewhat near the female contact end  26 . This larger region  72  is used to provide space for the cylindrical spring sleeve  78  shown in  FIG. 4 . There are beveled openings  32  at the contact end  26  of the female component. The flexible seals  30  of the male component  12  seat against the beveled openings  32  when the connector is made up. 
       FIG. 8  shows a cut-away of a male component  12  and female component  14  connected together. This drawing is for illustration purposes only, as these two parts of the connector would be installed in rigid outer shells before the connector is made up and used. The three insulator layers of the male component are shown: the large flexible region  44 , the rigid middle layer  46 , and the thin, flexible later  48 . The pins  16  are shown fully inserted into the receptacles  18 . The flexible seals  30  are deformed radially outward and are seated against the beveled openings  32  of the female contact end  26 . 
     The longitudinal slot  76  illustrated in detail in  FIG. 4  may also be seen in  FIG. 8 . The slot  76  extends from the end of the receptacle positioned near the female contact end  26  to a point near or beyond the position of the tip of a male pin  16 , when the pin  16  is fully inserted into the receptacle  18 . This allows most or all of the contact region of the receptacle  18  to expand and contract slightly, thus enhancing the wiping of the pins  16  and improving the electrical connection (i.e., reducing the electrical resistance) between the pins  16  and receptacles  18 . The slot may extend past the full pin-insertion point or may terminate near that point. 
     The rigid insulator region  68  of the female component  14  is also shown.  FIG. 8  also shows the cylindrical spring sleeve  78  and part of the slotted region of the receptacles  18 , though these two features are illustrated more clearly in  FIG. 4 . 
       FIG. 9  is a full-length version of the connection illustrated in  FIG. 8 . In addition to the features shown in  FIG. 8 , one can see the cable end components in  FIG. 9 . The male cable end  34  and female cable end  60  form the opposite ends of the connector. The flexible, cylindrical seals  38  within the sockets ( 56  and  70 ) are shown near the two cable ends. 
     The large flexible insulator region  66  of the female component  14  is shown, as is the rigid outer support ring  54 , which is used in the same manner as described above for the male component  12 . The receptacle wire connection end  80  and the pin wire connection end  82  also are shown. In practice, wires would be connected to the receptacles and pins, and a crimp connection is widely used, though other connecting methods are fully within the scope of the invention. Wires  26  (not shown) would then extend out from each end of the connector and would be sealed within the sockets by the flexible, cylindrical seals  38 . 
     Finally,  FIG. 10  shows a fully made up multi-pin connector  10 . The male component  12  is installed within a first external shell  52 , and the female component  14  is installed within a second external shell  62 . The external shells are typically made of steel, but any suitable, rigid material may be used. A mounting flange  84  is shown as part of the second external shell  62 , and allows the female component  14  to be mounted to a panel. 
     This configuration is entirely optional, but illustrates the variety of applications in which the invention could be used. It could be a cable to cable connection, for example, to extend the length of a multi-line cable run. The invention also may be used in panel-mounted applications, included panels of machines or other equipment. In addition, the invention could be used as a single, cable-end connector, in either male or female form, and configured to be plugged into an existing multi-pin receptacle installed on an existing instrument, machine, control panel, or other item. 
     Multi-pin connections are somewhat common on a variety of control, instrumentation, and data processing equipment. A connector embodying the present invention may be beneficially used at the end of a cable that is to be connected to these types of equipment. For example, where data processing equipment is used in an oilfield operation, there may be an increased risk of water infiltrating into connectors. A multi-pin connector embodying the present invention may be used to eliminate the problem of cross-talk in this type of application, which could have substantial benefits. 
     It also should be understood that the present invention may be a complete connector—that is, both male and female components—or just the male or female component. Consider, for example, an existing multi-pin connection installed in a panel of some piece of equipment, a control or instrumentation panel, or any other application. If that connection has been suitably designed to prevent water intrusion, use of a cable-end connector in accordance with the present invention may be sufficient to eliminate the cross-talk resulting from water infiltration. To be more specific, in this type of application, the cable-end connector would prevent water from shorting any of the live contact surfaces within the cable-end connector, and may also provide water-tight seals around the pin connections between the cable-end connector and the installed panel connection. 
     Single connectors (i.e., either male or female alone) embodying the present invention also may be used with prior art connectors. The full benefits of the invention may not be realized in such applications, because the prior art connector may allow water infiltration, causing shorting within the prior-art connector. Nevertheless, using one connector with the advantages of the present invention may eliminate some sources of possible water-based shorting, and thus, reduce the risk of cross-talk. In addition, connectors embodying the present invention provide all the ordinary functionality of other multi-pin connectors, and thus can be used interchangeably with such connectors. By replacing prior art connectors with the more protected connectors of the present invention, one can enhance the reliability of a system and reduce the overall risk of cross-talk. Eliminating or isolating any pockets of water, as accomplished by the present invention, may be beneficial in a wide variety of settings. The invention claimed below is not limited to any particular application. 
       FIG. 10  also shows external securing threads  86  on the female component  14 , and a threaded securing ring  88  is shown on the male component  12 . Other methods of obtaining a secure connection are fully within the scope of the invention, including the use of no additional securing mechanism. In many settings, the fitting between the male and female components may be sufficient. The embodiment shown in  FIG. 10  is suitable for use in extreme conditions, such as those experienced in offshore oil or gas drilling operations. In the configuration shown, the ring  88  is threaded onto the external threads  86  and then tightened, thus pulling the male and female components together in a secure manner. 
     While the preceding description is intended to provide an understanding of the present invention, it is to be understood that the present invention is not limited to the disclosed embodiments. To the contrary, the present invention is intended to cover modifications and variations on the structure and methods described above and all other equivalent arrangements that are within the scope and spirit of the following claims.