| 摘要 |
1301262 Sparking plugs HAMILTONHASTINGS CO Ltd 7 Jan 1970 [8 Jan 1969] 818/70 Heading F1B A spark plug comprises a metallic shell member 10 having an upwardly opening cavity 13 and an opening 16 extending downwardly therethrough from the bottom of the cavity, a scavenging chamber 26 extending downwardly from the opening. A one piece ceramic insulating member 17 is sealingly mounted in the cavity and has an integral thin walled tubular portion 18 which is of relatively small substantially constant cross sectional area throughout the length of the tubular portion which extends downwardly from the opening. The scavenging chamber is of relatively small depth and large cross-sectional area relative to the tubular portion of the insulating member, the opening being of only slightly larger crosssectional area than the downwardly extending tubular portion to assist in heat transfer therebetween. Centre electrode mean 19, 20 extends through a coaxial opening provided in the insulating member and its tubular portion and the tubular portion extends a predetermined distance downwardly beyond the top of the scavenging chamber to determine the heat range. The heat range of the plug may be varied by boring a scavenging chamber of relatively large cross-sectional area and controlling the depth of the chamber in accordance with a desired heat range. |
