Patent Publication Number: US-7713098-B2

Title: Single use security module mezannine connector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a divisional application of application Ser. No. 11/751,744 filed May 22, 2007 now U.S. Pat. No. 7,470,129. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to electrical connectors. More specifically, the present invention relates to a mezzanine-style electrical connector for connecting a first electrical component to a second electrical component. 
     BACKGROUND OF THE INVENTION 
     Electrical connectors provide signal and power connection between electronic devices using signal and power contacts supported within a connector housing. For example, computers and other electronic devices often include a plurality of interconnected printed circuit boards (PCBs) connected by electrical connectors. It is common for a computer to have a motherboard and one or more other boards that execute or perform specialized operations or tasks. These specialized boards are often referred to as daughter cards. The connectors connecting these PCBs provide for the transfer of power and/or control signals between the PCBs. 
     A connector which includes a housing and contacts is attached to a first PCB, such as a daughter card, by connecting one end of the contacts on a first side of the connector housing to electrical contacts on a surface of the first circuit board. Often, this connection is made by soldering so as to permanently attach the connector to the first PCB. The connector is then attached to a second PCB, which may be a motherboard, by press-fitting leads of the contacts on a second side of the connector into plated through holes of the second PCB. In such a manner, the connector provides an electrical connection, as well as a physical connection, between the two circuit boards. Since the connector is attached by a removable press-fit connection with the second PCB, the first PCB along with the connector, may be removed from the second PCB and reused. 
     It some circumstances, it may be desirable to provide a security measure to prohibit or deter removing a first PCB from a second PCB, for example, to prohibit the first PCB from being reused. At this time, no practical system or method has been developed to render inoperative a first PCB when removed from a second PCB. 
     Furthermore, no practical method has been developed to render unusable a connector attached to a first electrical device when removed from a second electrical device or another connector attached to another electrical device. 
     Therefore, there is an unmet need to provide an electrical connector which is rendered unusable upon separation from an electrical device or another connector to which the connector has been previously joined. 
     SUMMARY OF THE INVENTION 
     An electrical connector assembly providing for a single use connection is disclosed. The electrical connector is rendered unusable after being removed from an electrical device or other connector to which the connector has been previously joined. 
     In a first embodiment of the electrical connector assembly, the connector includes a housing, at least one electrical contact supported by the housing, and a tool that mates with the housing, wherein the at least one electrical contact comprises a first end configured to make a first connection with a first electrical device, a second end configured to make a second connection with a second electrical device, and a compliant jog section disposed between the first end and the second end and wherein the compliant jog section is configured to deform when attempting to connect the second end to the second electrical device without the tool mated to the housing so as to prevent the second end from making the second connection with the second electrical device. 
     The connector of the first embodiment further includes wherein the first end is a solder lead and the second end is a press-fit connection, and further includes wherein the second end comprises a compliant eye-of-the-needle tail. The connector housing has an open slot for receiving the tool. 
     In a second embodiment of the electrical connector assembly, the connector includes a first housing and a standard contact, and a second connector comprising a second housing, a standard contact and a modified contact, wherein the first connector and the second connector are configured to mate so as to engage the standard contact of the first connector and the modified contact of the second connector, and wherein the modified contact of the second connector is deformed and rendered unusable when the second connector is un-mated from the first connector. 
     The connector assembly of the second embodiment further includes wherein the first housing and the second housing are substantially identical. The connector assembly of the second embodiment additionally includes wherein the second housing comprises a standard slot configured to support the standard contact and a modified slot configured to support the modified contact, and wherein the first connector housing comprises a slot overhang configured to deform the modified contact of the second connector when the second connector is un-mated from the first connector. 
     The connector assembly of the second embodiment additionally includes wherein the second connector housing further comprises at least two standard slots and at least two modified slots. The connector assembly also includes wherein the second connector housing further comprises a first row of five standard slots and five modified slots and a second row of five standard slots and five modified slots, and wherein the standard and the modified slots of each row are individually staggered. 
     The connector assembly of the second embodiment further includes wherein the standard contact of the first connector and the standard contact of the second connector are substantially identical, and wherein the standard contact of the first connector comprises a first end configured to make a first connection with an electrical device, a second end configured to make a second connection with either a standard contact or a modified contact, and wherein the modified contact of the second connector comprises a first end configured to make a first connection with a second electrical device, and a second end configured to make a second connection with either a standard contact or a modified contact. 
     The connector assembly of the second embodiment also includes wherein the first connector further comprises a modified contact that is substantially identical to the modified contact of the second connector, and also includes wherein the modified contact of the first connector further comprises a frangible section that has a lower tensile strength compared to any other section of the modified contact and that is configured to bend or break when the second connector is un-mated from the first connector, and also includes wherein the first electrical device is a motherboard and the second electrical device is a daughter card. 
     In a method of electrically connecting a first electrical device to a second electrical device, a method is disclosed that includes providing a first electrical device, connecting a first connector comprising a first housing and a standard contact to the first electrical device to make a first electrical connection, providing a second electrical device, and connecting a second connector comprising a second housing, a standard electrical contact and a modified electrical contact to the second electrical device to make a second electrical connection, and mating the first connector to the second connector to form an electrical connection between the first electrical device and the second electrical device, wherein the first housing and the second housing are substantially identical, and wherein the modified contact of the second connector is deformed and rendered unusable when the second connector is un-mated from the first connector. 
     The method further includes wherein the first housing comprises a standard slot for supporting the standard electrical contact and a modified slot for supporting the modified electrical contact, and wherein the first housing comprises a slot overhang configured to deform the modified electrical contact of the second connector when the second connector is un-mated from the first connector. The method additionally includes wherein the standard contact of the first connector comprises a first end configured to make a first connection with the first electrical device, a second end configured to make a second connection with either a standard contact or a modified contact, and wherein the standard contact of the first connector is substantially identical to the standard electrical contact of the second connector, and wherein the modified electrical contact of the second connector comprises a first end configured to make a second connection with the second electrical device, and a second end configured to make a second connection with either a standard contact or a modified contact. 
     The method also includes wherein the first connector further comprises a modified electrical contact that is substantially identical to the modified contact of the second connector and wherein the modified electrical contact of the second connector further comprises a frangible section that has a lower tensile strength compared to any other section of the modified electrical contact. The method further includes wherein the first electrical device is a motherboard and the second electrical device is a daughter card. 
     Further aspects of the method and system are disclosed herein. The features as discussed above, as well as other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary electrical connector according to a first embodiment of the invention. 
         FIG. 2  illustrates an exemplary connector housing according to a first embodiment of the invention. 
         FIG. 3  illustrates a detailed view of an exemplary contact according to a first embodiment of the invention. 
         FIG. 4  illustrates an exemplary connector tool according to a first embodiment of the invention. 
         FIG. 5  illustrates a first exemplary daughter card. 
         FIG. 6  illustrates an exemplary arrangement of the connector according to the first embodiment connected to an exemplary daughter card. 
         FIG. 7  illustrates a first exemplary motherboard. 
         FIG. 8  illustrates an exemplary arrangement of the first embodiment of the connector attached to an exemplary daughter card being further attached to an exemplary motherboard. 
         FIG. 9  illustrates an exemplary arrangement of the first embodiment of the connector connecting an exemplary daughter card to an exemplary motherboard. 
         FIG. 10  illustrates an exemplary electrical connector according to a second embodiment of the invention. 
         FIG. 11  illustrates a bottom view of an exemplary electrical connector according to a second embodiment of the invention. 
         FIG. 12  illustrates an exemplary standard contact according to the second embodiment of the invention. 
         FIG. 13  illustrates an exemplary modified contact according to the second embodiment of the invention. 
         FIG. 14  illustrates a second exemplary motherboard. 
         FIG. 15  illustrates an exemplary arrangement of a first connector according to the second embodiment connected to an exemplary motherboard. 
         FIG. 16  illustrates a second exemplary daughter card. 
         FIG. 17  illustrates an exemplary arrangement of a second connector according to the second embodiment connected to an exemplary daughter card. 
         FIG. 18  illustrates an exemplary arrangement of a first connector connected to a motherboard aligned with a second connector connected to a daughter card. 
         FIG. 19  illustrates an exemplary arrangement of a first connector connected to a motherboard mated to a second connector connected to a daughter card. 
         FIG. 20  illustrates a cross-sectional view of a first connector connected to a motherboard mated with a second connector connected to a daughter card taken across modified slots. 
         FIG. 21  illustrates a cross-sectional view of a first connector connected to a motherboard mated with a second connector connected to a daughter card taken across standard slots. 
         FIG. 22  illustrates a cross-sectional view of a first connector connected to a motherboard un-mated by a distance D from a second connector connected to a daughter card taken across standard slots. 
         FIG. 23  illustrates a cross-sectional view of a first connector connected to a motherboard un-mated by a distance D′ from a second connector connected to a daughter card taken across standard slots. 
         FIG. 24  illustrates a cross-sectional view of a first connector connected to a motherboard un-mated by a distance D″ from a second connector connected to a daughter card taken across standard slots. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention now will be described more fully hereinafter with reference to the accompanying drawing, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. 
     Referring to  FIG. 1 , a first embodiment of the single use security module connector  10  is depicted. The connector  10  includes a housing  20  and contacts  30 . Contacts  30  include leads  40  and compliant tails  50 . The contacts  30  extend through the housing  20  between the leads  40  and the tails  50 . 
     The housing  20  includes an open slot  60  and alignments posts  70 . The housing  20  is shown with two posts  70  on the lead side surface  25  of the housing  20 . The posts  70  align the housing  20  with a first electrical device such as a printed circuit board (PCB), and more particularly with a daughter card. Although two posts  70  are preferable, it is within the scope of the invention to include fewer posts, additional posts, or other alignment structures. 
     A detailed illustration of housing  20  is shown in  FIG. 2 . The open slot  60  is shown having a length L, a width W, and a height H. As further shown in  FIG. 2 , housing  20  includes an upper contact groove  200 , a lower contact groove  210  and a lower slot  215  for supporting the contact  30 . The lower slot  215  extends from the lead side surface  25  to allow the tail  50  to exit the tail side surface  27  of the housing  20  as shown in  FIG. 6 . The housing further includes standoffs  28 . The standoffs  28  provide for a separation between the lead side surface  25  of the housing  20  and an electrical device to which the leads  40  may be connected. As shown, the standoffs  28  may support alignment posts  70 . 
     A detailed illustration of contact  30  is shown in  FIG. 3 . As shown in  FIG. 3 , the contact  30  has a lead  40  and a compliant eye-of-the-needle tail  50 . The contact includes a compliant jog section  320 , a T-section  330 , and a lower section  340 . The compliant eye-of-the-needle tail  50  is configured to compress when pushed into a through hole or other receiving structure of a second electrical device to form a friction fit with good electrical contact. 
     The contact  30  is loaded into the housing  20  by inserting the tail  50  into the lower slot  215  while the T-section  330  is aligned to enter the upper contact groove  200 . The contact  30  is inserted until the jog section  320  seats in the lower contact groove  210  which is open to the slot  60 . The T-section  330  frictionally fits within the upper contact groove  200  to support the contact  30  in the housing  20 . The tails  50  extend beyond the tail side surface  27  as shown in  FIG. 6 . 
     An installation tool  400  is shown in  FIG. 4 . Installation tool  400  is designed to fit within open slot  60  of housing  20 , and is formed with a length L′, a width W′, and a height H′ as shown in  FIG. 4 . The length L′ of installation tool  400  is preferably slightly longer than the length L of open slot  60 . The width W′ and height H′ of the installation tool  400  are slightly less than the corresponding width W and height H of the open slot  60  so as to provide a snug fit of the tool  400  into the open slot  60 . 
     A first exemplary daughter card  500  is shown in  FIG. 5 . Daughter card  500  includes surface mount pads  510  and alignment holes  520  on a daughter card surface  530 . Surface mount pads  510  correspond to the leads  40  of connector  10  as shown on  FIG. 1 . Alignment holes  520  correspond to alignment posts  70  of connector  10  as shown on  FIG. 1 . Alignment holes  520  may pass through the daughter card  500  or may be recessed into the daughter card  500 . 
     When the posts  70  of the connector are aligned with corresponding alignment holes  520  on the daughter card  500 , the leads  40  are aligned with the surface mount pads  510  on the daughter card  500 . The standoffs  28  create a space between the lead side surface  25  of the housing  20  and the daughter card surface  530  that facilitates soldering the leads  40  to the pads  510 . 
     As shown in  FIG. 6 , the connector  10  is attached to a first electrical device, in this embodiment a daughter card  500 . Alignment posts  70  (not shown) are positioned in alignment holes  520  (not shown) and the leads  40  of the connector  10  are soldered to the corresponding surface mount pads  510  of daughter card  500 . Open slot  60  faces the daughter card  500  as shown in  FIG. 6 . In such a manner, an electrical connection is established between the tails  50  and the daughter card  500 . Optional alignment posts (not shown) may be provided on the tail side surface  27  of the housing  20 . 
     A first exemplary motherboard  700  as shown in  FIG. 7  is then provided. Motherboard  700  includes through holes  710 . Through holes  710  provide electrical connectivity to electrical pathways (not shown) on the motherboard  700 . The motherboard  700  may have optional alignment holes (not shown) for receiving optional alignment posts of the connector  10  (not shown). 
     To connect the connector  10  connected to the daughter card  500  to the motherboard  700 , the tool  400  is inserted into the open slot  60  between the connector  10  and the daughter card  500 . The tails  50  of the connector  10  are then aligned and press-fit through the through holes  710  of the motherboard  700  as shown in  FIG. 8 . The tool  400  prevents the tails  50  from being pushed up into the housing  20  and bending the compliant jog section  320  shown in  FIG. 3  into the open slot  60  shown in  FIG. 6 . The tool  400  is then removed from the slot  60 . In such a manner, an electrical connection is established between the motherboard  700  and the daughter card  500  through the connector  10  as shown in  FIG. 9 . If the connector  10  is removed from the motherboard  700  by withdrawing the leads  50  from the through holes  710 , the connector  10  cannot be reused unless a tool  400  is again provided to assist in the press-fitting of the tails  50  into another electrical device. 
     A second embodiment of the single use security module first connector  1000  is depicted in  FIG. 10 . The first connector  1000  includes a housing  1020  and standard contacts  1030  and modified contacts  1035 , as shown in the partial cutaway view of connector  1000  in  FIG. 10 . The standard contacts  1030  include a lead  1040 , a body  1045 , and a contact engaging tail  1050 . The standard contacts  1030  are supported in the housing  1020  in standard slots  1022  The modified contact  1035  include a lead  1040 , a body  1045 , and a modified engaging tail  1055 . The modified contacts  1035  are supported in the housing  1020  in modified slots  1024 . As further shown in  FIG. 10 , housing  1020  further includes interlocking sidewalls  1026  and a bottom wall  1028 . Bottom wall  1028  includes standoffs  1029 . 
     The first connector  1000  is shown with two rows of contacts containing five standard slots  1022  and five modified slots  1024  in each row, however, each row may have any number of standard slots  1022  and modified slots, including zero. For example, a row may contain one or more standard slots  1022  and the other row may contain one or more modified slots  1024 . Additionally, the first connector  1000  is shown with individually alternating standard slots  1022  and modified slots  1024 , however, the standard slots  1022  and modified slots may be staggered in groups of two or more. Furthermore, the standard slots  1022  and the modified slots  1024  may also be grouped together in a row, for example, 5 modified slots together and 5 standard slots together. 
     A detailed bottom view of connector  1000  is shown in  FIG. 11 . As seen in  FIG. 11 , the bottom wall  1028  includes a housing lead side surface  1110 . Alignment posts  1120  are positioned on the lead side surface  1110  as shown in  FIG. 11 . Alignment posts  1120  align the connector  1000  with a surface of an electrical device (not shown). The housing  1020  is shown with two alignment posts  1120  on the lead side surface  1110  of the housing  1020 , but it is within the scope of the invention to include additional alignment posts or other alignment structures on the lead side surface  1110 .  FIG. 11  also shows standoffs  1029  positioned on the ends of lead side surface  1110 . Additional standoffs  1129  are also provided. Further standoffs may be provided as necessary to provide support to the bottom wall  1028 . 
     A detailed illustration of a standard contact  1030  is shown in  FIG. 12 . As shown in  FIG. 12 , the standard contact  1030  has a lead  1040 , a body  1045  and an engaging tail  1050 . The engaging tail  1050  includes a tip section  1051  that is directed towards the body  1045  as shown in  FIG. 12 . The engaging tail  1050  also includes an engaging surface  1052 . The body  1045  includes retention shoulders  1046  for holding the standard contact  1030  in the standard slot  1022  of the housing  1020  by a friction fit. 
     A detailed illustration of a modified contact  1035  is shown in  FIG. 13 . As shown in  FIG. 13 , the modified contact has a lead  1040 , a body  1045 , and a modified engaging tail  1055 . The modified engaging tail  1055  includes a modified tip section  1053  that is directed away from the body  1045  as shown in  FIG. 13 . The modified engaging tail  1055  also includes an engaging surface  1052  and a frangible section  1054 . The body  1045  includes retention shoulders  1046  that assist in holding the modified contact  1035  in the slot  1024  of the housing  1020  by a friction fit. 
     In the example of the modified contact shown in  FIG. 13 , the frangible section  1054  is shown having a reduced cross-section. However, the frangible section  1054  may be weakened by either mechanical design or chemical or metallurgical treatment to ensure that the modified contact  1035  is weakest at the frangible section  1054 . The weakened mechanical design can be formed, for example, by reducing the cross-section, thinning the material, or providing for a weaker material at the frangible section  1054 . 
     Both the standard contact  1030  and the modified contact  1035  are loaded into housing  1020  by inserting the engaging tail  1050  and modified engaging tail  1055  into the standard slot  1022  and the modified slot  1024 , respectively, from the lead side surface  1110  of the housing  1020  until the contact body  1045  of both the standard contact  1030  and the modified contact  1035  abut the housing ledge  1032  as shown in  FIG. 10 . 
     A second exemplary motherboard  1400  having a motherboard surface  1405  supporting surface mount pads  1410  is shown in  FIG. 14 . The motherboard  1400  further includes alignment holes  1420 . A first connector  1000  is brought into contact with motherboard  1400  to bring alignment posts  1120  into alignment with alignment holes  1420  and to position leads  1040  against surface mount pads  1410 . 
     The leads  1040  of the connector  1000  are then soldered to the surface mount pads  1410  of the motherboard  1400  to form the connector/motherboard arrangement as shown in  FIG. 15 . The standoffs  1029  separate the lead side surface  1010  of the first connector  1000  from the motherboard surface  1405  and facilitate soldering of the leads  1040  to the surface mount pads  1410 . In such a manner, an electrical connection is established between the connector  1000  and the motherboard  1400 . 
     A second exemplary daughter card  1600  having a daughter card surface  1605  that supports surface mount pads  1610  is shown in  FIG. 16 . The daughter card  1600  further includes alignment holes  1620 . A second connector  1100  is brought into contact with the daughter card  1600  so that the alignment posts  1020  are aligned with alignment holes  1620  and the leads  1040  are positioned against surface mount pads  1610 . The second connector  1100  has a substantially identical housing  1020  as the first connector  1000 . However, in the second connector  1100 , the standard contacts  1030  are positioned in the modified slots  1024  and the modified contacts  1035  are positioned in standard slots  1022 . 
     The leads  1040  of the second connector  1100  are then soldered to the surface mount pads  1610  of the daughter card  1600  to form a connector/daughter card arrangement as shown in  FIG. 17 . The standoffs  1029  separate the lead side surface  1010  of the connector  1010  from the motherboard surface  1605  and facilitate soldering of the leads  1040  to the surface mount pads  1610 . In such a manner, an electrical connection is established between the connector  1100  and the motherboard  1600 . 
     The second connector  1100  attached to the daughter card  1600  is brought into contact with the first connector  1000  attached to the motherboard  1400  as shown in  FIG. 18 . As seen in  FIG. 18 , reversing the orientation of the second connector  1100  with respect to the first connector  1000  and aligning the second connector  1100  with the first connector  1000  allows the second connector  1100  and the first connector  1000  to be mated. In such a manner, the standard slots  1022  of the first connector  1000  are aligned with the standard slots  1022  of the second connector  1100 , and the modified slots  1024  of the first connector  1000  are aligned with the modified slots  1024  of the second connector  1100 . The interlocking sidewalls  1026  of the second connector  1100  are configured to mate with the interlocking sidewalls  1026  of the first connector  1000  when the second connector  1100  and the first connector  1000  are mated as shown in  FIG. 19 . 
     A first cross section of a fully mated first connector  1000  connected to motherboard  1400  and a second connector  1100  connected to a daughter card  1600  taken across a standard slot  1024  of both the first connector  1000  and the second connector  1100  is shown in  FIG. 20 . As shown in  FIG. 20 , the modified slot  1024  of the first connector  1000  supports a modified contact  1035 . As also shown in  FIG. 20 , the modified slot  1024  of the second connector  1100  supports a standard contact  1030 . As can be seen in  FIG. 20 , the mating of the modified slot  1024  of the first connector  1000  with the modified slot  1024  of the second connector  1100  forms a space (a) that allows the second connector  1100  to become un-mated from the first connector  1000  without engaging the modified tip section  1053 . In this configuration, the second connector  1100  can be un-mated from the first connector  1000  without deforming the modified tip section  1053  of the modified contact  1035  of the first connector  1100 . 
     A second cross section of a fully mated first connector  1000  connected to motherboard  1400  and second connector  1100  connected to daughter card  1600  taken across a standard slot  1022  of the first connector  1000  and a standard slot  1022  of the second connector  1100  is shown in  FIG. 21 . As shown in  FIG. 21 , the standard slot  1022  of the first connector  1000  is partially bound by slot overhang  1021 , which is a part of housing  1020  of the first connector  1000 . The standard slot  1022  of the second connector  1100  supports modified contact  1035 . 
       FIG. 22  illustrates the un-mating of second connector  1100  from the first connector  1000  at the second cross-section when the second connector  1100  is separated from the first connector  1000  by a distance D. At distance D, the modified tip section  1053  of the modified contact  1035  first engages the slot overhang  1021  of housing  1020  of the first connector  1000 . 
       FIG. 23  illustrates the un-mating of the second connector  1100  from the first connector  1000  at the second cross-section when the second connector  1100  is separated from the first connector  1000  by a distance D′. At distance D′, the modified tip section  1053  of the modified contact  1035  has been deformed by the slot overhang  1021  of housing  1020  of the first connector  1000 . 
       FIG. 24  illustrates the un-mating of the second connector  1100  from the first connector  1000  at the second cross-section when the second connector  1100  is separated from the first connector  1000  by a distance D″. At distance D″, the modified tip section  1053  has been substantially deformed by the slot overhang  1021  of housing  1020  of the first connector  1000 .  FIG. 24  also shows the modified contact  1035  has bent at the frangible section  1054  to substantially deform the modified tail  1055  of the modified contact  1035 . 
     When the second connector  1100  is fully un-mated from first connector  1000 , the modified tail  1055  is either fully deformed or broken away from the modified contact  1035  at the frangible section  1054 . In either condition, the connector  1100  is rendered unusable. 
     It may be desirable to render first connector  1000  alone, or with the second connector  1100 , unusable after mating, and therefore, modified contacts  1035  may be loaded in the standard slots  1022  of the first connector  1000 . In such a manner, the modified contacts  1035  of the first connector  1000  would be deformed when the second connector  1100  is un-mated from the first connector  1000 , rendering the first connector  1000  unusable. Additionally, it may be desirable to load only standard contacts  1030  into the first connector  1000 . 
     The standard contacts  1030  and the modified contacts  1035  may be formed of a highly conductive metal or alloy, such as phosphor bronze. The housing  1020  may be formed of a high temperature liquid crystalline polymer (LCP) or other known industry acceptable non-conductive high temperature resin. 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.