SEMI-RIGID HIGH-VOLTAGE EXTENDER

Abstract

An extender for connecting a high-voltage source to a spark plug has a conductive member, a tube having an interior passageway in which the conductive member is positioned therein, and a boot affixed over an exterior of the tube. The boot is formed of a material having a rigidity less than a rigidity of a material of the tube. The boot has a first end adapted to connect with the high-voltage source and a second end adapted to be connected to the spark plug such that the conductive member is in electrical connection with the spark plug and the high-voltage source. The conductive member includes a spring that is adapted to electrically connect with the high-voltage source and the spark plug.

Claims

1. An extender for connecting a high-voltage source to a high-voltage terminal of a spark plug, the extender comprising: a spring being conductive and adapted to connect at one end with the high voltage source and at another end to the spark plug; a tube having an interior passageway, said spring having at least a portion positioned in said interior passageway of said tube; and a boot affixed over an exterior of said tube, said boot being formed of a material having a rigidity less than a rigidity of a material of said tube, said boot having a first end adapted to connect with the high-voltage source and a second end adapted to be connected to the spark plug such that said spring is in direct electrical connection with the spark plug and the high-voltage source, said tube having an end positioned inwardly of said second end of said boot so as to be spaced longitudinally away from the high-voltage terminal of the spark plug.

2. (canceled)

3. The extender of claim 1, wherein said spring extends longitudinally through an interior of said boot, said tube overlying a portion of said spring.

4. The extender of claim 1, wherein said boot has a first portion and a second portion that is affixed to an end of said first portion, said first portion adapted to connect with the high-voltage source, said second portion adapted to connect to the spark plug.

5. The extender of claim 4, wherein said first portion has a rigidity that is less than a rigidity of said second portion.

6. The extender claim 5, wherein said first portion is formed of a silicone rubber material, said second portion being formed of a material selected from the group consisting of polyethylene terephthate, liquid crystal polymer and a polytetrafluoroethylene.

7. The extender claim 4, wherein said first portion has at least one annular notch formed in an inner wall thereof adjacent an end of said first portion opposite the end adapted for connection to the high-voltage source, said second portion having an insert element fitted within said first portion, said second portion having a protrusion received in the annular notch.

8. The extender of claim 1, wherein said tube has a flange formed adjacent one end thereof, said boot having an internal shoulder formed adjacent to the end adapted for connection to the high-voltage source, said flange abutting said interior shoulder.

9. The extender of claim 1, further comprising: an O-ring affixed within said boot adjacent to the end adapted for connection to the spark plug, said O-ring adapted to engage a terminal of the spark plug.

10. An ignition system comprising: a high-voltage source; a spark plug having a high-voltage terminal; a conductive spring having one end directly electrically connected to said high-voltage source and an opposite end directly electrically connected to said spark plug; a tube having an interior passageway, said conductive spring having at least a portion positioned in said interior passageway of said tube, said tube having an end positioned longitudinally away from the high-voltage terminal of said spark plug; and a boot affixed over an exterior of said tube, said boot having a first end connected to said high-voltage source and an opposite end connected to said spark plug, said end of said tube being longitudinally inwardly of said opposite end of said boot.

11. The ignition system of claim 10, wherein said tube is formed of a material having a rigidity greater than a rigidity of a material of said boot.

12. (canceled)

13. The ignition system of claim 10, wherein said spring extends longitudinally through an interior of said boot, said tube overlying at least a portion of said conductive spring.

14. The ignition system of claim 10, wherein said boot has a first portion and a second portion that is affixed to an end of said first portion, said first portion connected to the high-voltage source, said second portion connected to said spark plug.

15. The ignition system of claim 14, wherein said first portion has a rigidity that is less than a rigidity of said second portion.

16. The ignition system of claim 14, wherein said first portion has at least one annular notch formed in an inner wall thereof adjacent an end of said first portion opposite the end connected to said high-voltage source, said second portion having an insert element fitted within said first portion, said second portion having a protrusion on said insert element that is received in the annular notch.

17. The ignition system of claim 10, further comprising: an O-ring affixed within said boot adjacent the end of said boot connected to said spark plug, said O-ring engaging a terminal of said spark plug.

18. An extender for connecting a high-voltage source to a high-voltage terminal of spark plug, the extender comprising: a spring that is conductive and adapted to connect directly with the high-voltage source and the high-voltage terminal of the spark plug; a tube having an interior passageway, said conductive member having at least a portion positioned in said interior passageway of said tube; and a boot affixed over an exterior of said tube, said boot having a first end adapted to connect with the high-voltage source and a second end adapted be connected to the spark plug such that said spring is in direct electrical connection with the high-voltage terminal spark plug and the high-voltage source, said boot having a first portion and a second portion that is affixed to an end of said first portion, said first portion adapted to connect with the high-voltage source, said second portion adapted to connect to the spark plug, said first portion having a rigidity less than a rigidity of said second portion, said tube having an end positioned longitudinally inwardly of an end of said second portion of said boot opposite said first portion of said boot so as to be spaced longitudinally away from the high-voltage terminal of the spark plug.

19. The extender of claim 18, wherein said boot is formed of a material having a rigidity less than a rigidity of a material of said tube.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0035] FIG. 1 is a cross-sectional view of a prior art extender.

[0036] FIG. 2 is a side elevational view showing the extender of the present invention as secured to a high-voltage source

[0037] FIG. 3 is a cross-sectional view, in perspective, of the extender in accordance with a first embodiment of the present invention.

[0038] FIG. 4 is a cross-sectional view of the extender of the first embodiment of the present invention.

[0039] FIG. 5 is a perspective view showing the extender in accordance with a second embodiment of the present invention.

[0040] FIG. 6 is a cross-sectional view of the extender of the second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0041] Referring to FIG. 2, there shown the high-voltage extender 50 in accordance with a first embodiment of the present invention. The high-voltage extender 50 is a longitudinal member that has a boot 52 extending over the exterior surface of a conductive member. In particular, the boot 52 has a connector 54 at one end thereof. Connector 54 is illustrated as connected to a high-voltage source 56, such as an ignition coil. The boot 52 has an opposite end 58 that is adapted to connect with a terminal 60 of a spark plug. The high-voltage extender 50 is intended to transmit electrical energy from the high-voltage source 56 to the terminal 60 of the spark plug.

[0042] FIG. 3 illustrates a cross-sectional view of the first embodiment of the extender 50 of the present invention with the conductive member omitted. In particular, it can be seen that the extender 50 has the boot 52 extending longitudinally with a connector 54 at one end and a connector 58 at an opposite end thereof. In particular, as will be described hereinafter, an O-ring can be affixed within the end 58 so as to securely connect the boot 52 to the spark plug terminal 60 so that an electrical connection can be established between the high-voltage source 56 and the spark plug.

[0043] In FIG. 3, it can be seen that there is a tube 64 that is affixed within the interior of the boot 52. The tube 64 can be inserted into the interior passageway 66 of the boot 52 or the boot 52 can be over-molded onto the tube 64 such that there are no voids between the exterior of tube 64 and the interior of boot 52. As can be seen, the tube 64 extends for a portion of the length of the interior 66 of the boot 52. The tube 64 includes a protrusion 68 adjacent to the connector 54 which is received within an annular notch 70 formed in the inner wall of the boot 52. The tube 64 also has an interior passageway 72 into which the conductive member is received.

[0044] Importantly, in the present invention, the tube 64 will have a rigidity that is greater than the rigidity of the boot 52. In particular, the boot 52 can be formed of an MS115 silicone rubber material. The tube 64 can be formed of a PET RE5329 material or a liquid crystal polymer material. As such, the tube 64 will provide rigidity to the silicone rubber material of the boot 52 for a substantial portion of the length of the boot 52. However, the outwardly extending end portion 74 of the boot 52 can be semi-flexible so as to compensate for slight angular misalignment between the high-voltage source 56 and the terminal 60 of the spark plug. The rigidity of the tube 64 will serve to protect the conductive member so as to avoid radial deflection of the conductive member.

[0045] FIG. 4 is a cross-sectional view of the extender 50. In FIG. 4, the conductive member 76 is illustrated as received within the tube 64 and within the interior of the boot 52. The conductive member 76 includes a spring 78 that extends from an end 80 to an end 82. End 80 is suitable for connection to a terminal of the high-voltage source 56. The end 82 is suitable for contacting the terminal 60 of the spark plug. The spring 78 is tightly positioned within the interior passageway of the tube 64 such that the tube 64 prevents radial deflection of the spring 78. However, the flexible end portion 74 of the boot 52 can suitably deflect, along with the spring contained therein. Once again, the interior diameter of the boot 52 in the area adjacent to the spring 78 near end 82 will be very close so as to further avoid radial deflection of the spring 78. Whenever the end 80 contacts the terminal of the high-voltage source 56 and the end 82 connects with the terminal 60 of the spark plug, an electrically conductive connection is achieved between the high-voltage source 56 and the spark plug. The spring 78 is preferably formed of Stainless Steel 304 material.

[0046] In FIG. 4, it can be seen that the inner wall of the boot 52 has an internal shoulder 86. The end of the tube 64 includes an annular flange 88. Annular flange 88 abuts the internal shoulder 86 so as to secure the position of the tube 64 within the boot 52. There is also another internal shoulder 90 formed on the inner wall of the boot 52. The end 92 of the tube 64 is securely abutted against the internal shoulder 90. Once again, this further serves to fix the position of the tube 64 within the boot 52.

[0047] As can be seen in FIG. 4, the polymeric tube 64 provides the necessary rigidity to the extender 50 during installation on to the spark plug. The semi-rigid nature of the extender 50 also allows for slight angular misalignment to the spark plug without compromising the dielectric integrity of the sealing at the spark plug. The special overlapping connection is designed prevent high-voltage tracking and withstand voltages in excess of 36 kV. An O-ring can be affixed within the end of the boot 52 so as to further seal around the terminal 60 of the spark plug. The spring 78 is contained internal of the tube 64 so as to offer dielectric strength and a means for minimizing the radial deflection of the spring.

[0048] FIG. 5 shows an alternative embodiment of the extender 100 in accordance with the teachings of the present invention. The extender 100 is illustrated as having the boot 102 having a first portion 104 and a second portion 106. The first portion 104 can be formed of an MS115 silicone rubber material. The second portion 106 can be formed of polytetrafluoroethylene (TEFLON) (™), PET or liquid crystal polymer material. As such, the second portion 106 will have a rigidity that is slightly greater than the rigidity of the first portion 104. A silicone rubber O-ring seal 108 is illustrated as positioned within the end 110 of the second portion 106. The first portion 104 has a connector 112 that is adapted to connect with the high-voltage source. The second portion 106 has an insert element (not shown) which is received within the end 114 of the first portion 104 of the boot 102.

[0049] FIG. 6 illustrates the internal configuration of the extender 100 of the alternative embodiment of the present invention. In particular, in FIG. 6, it can be seen that there is a conductive member 116 that is positioned within the interior of a tube 118. The conductive member 116 has a spring 120 arranged similar to that of the first embodiment.

[0050] The terminal 124 of the high-voltage source is illustrated as received within the connector 112 at one end of the extender 100. The terminal 124 will abut an end 126 of the spring 120. A terminal 128 of a spark plug is received within the O-ring seal 108 located at end 110 of the second portion 106 of the boot 102. The spring 120 has an opposite end that will abut the end of the terminal 128. The spring 120 extends longitudinally through the interior of the boot 102 and through the interior of the tube 118. As such, the spring 120 serves to provide an electrical connection between the terminal 124 of the high-voltage source and with the terminal 128 of the spark plug.

[0051] The first portion 104 of the boot 102 has an internal shoulder 130 formed adjacent to the connector 112. An annular flange 132 is formed at the end of the tube 118 so as to securely abut with the internal shoulder 130. The second portion 106 of the boot 102 includes an insert element 136 that is received within the end 114 of the first portion 104 of boot 102. In particular, there is a shoulder formed on the second portion 106 which will abut the end 114 of the first portion 104. An annular notch 138 is formed on an inner wall of the first portion 104 of boot 102. A protrusion 140 formed on the exterior of the insert element 106 of the second portion 108 can be secured within this annular notch 138. Within the concept of the present invention, a plurality of annular notches 138 can be formed in spaced planar parallel relationship to each other. Similarly, a plurality of protrusions 104 can also be provided on the exterior surface of the insert element 136 of the second portion 106 so as to further establish a secure connection between the portions 104 and 106 of boot 102.

[0052] In FIG. 6, it can be seen that the inner wall of the second portion 106 is in a tight fitting relation with the exterior surface of the spring 120. Similarly, the inner wall of the tube 118 is in tight fitting relationship with the exterior of the spring 120. As such, the serves to resist any radial deflection of the spring.

[0053] The surface between the high-voltage connection of the ignition coil and the extender utilizes O-ring seals on the extender 100 so as to seal the interface and to prevent high-voltage leakage. Because the tube is injection molded as an insert on the boot, the tube cannot move within the boot rotationally or lengthwise. This keeps the surface of the extender at the ignition coil and further prevents high-voltage leakage at this point. The materials used in the extender of the present invention are more resistant to the corona created in the engine block. During testing, the extender of the present invention achieved a longer period of use without failure compared to the extender of the prior art.

[0054] Experiments conducted with the high-voltage extender of the present invention, all embodiments, is able to withstand temperatures of up to 200° C. As such, the high-voltage extender is particularly useful in association with natural gas engines.

[0055] The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the present claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.