Lead out structure for lead circuit section of flexible printed circuitry

A structure comprising:

• a flexible printed circuitry including a lead circuit section integrally provided with a switch circuit section, and at least one engagement hole is formed on a part of the lead circuit section;
• a lower casing having a side wall provided with a cut out portion from which the lead circuit section is led out, and at least one boss to which the engagement hole is fitted to mount the flexible printed circuitry thereon;
• and
• an upper casing combined with the lower casing to constitute a casing which serves as a switch circuit unit, the upper casing having at least one hold-down member engaged with the boss to hold down the lead circuit section onto the lower casing,
• wherein the hold-down member is a tubular member into which the boss is fitted.

A structure comprising:

• a flexible printed circuitry including a lead circuit section integrally provided with a switch circuit section, and at least one engagement hole is formed on a part of the lead circuit section;
• a lower casing having a side wall provided with a cut out portion from which the lead circuit section is led out, and at least one boss to which the engagement hole is fitted to mount the flexible printed circuitry thereon;
• and
• an upper casing combined with the lower casing to constitute a casing which serves as a switch circuit unit, the upper casing having at least one hold-down member engaged with the boss to hold down the lead circuit section onto the lower casing,
• wherein a protective film is formed on the lead circuit section so as to surround the engagement hole.

A structure comprising:

• a flexible printed circuitry including a lead circuit section integrally provided with a switch circuit section, and at least one engagement hole is formed on a part of the lead circuit section;
• a lower casing having a side wall provided with a cut out portion from which the lead circuit section is led out, and at least one boss to which the engagement hole is fitted to mount the flexible printed circuitry thereon;
• and
• an upper casing combined with the lower casing to constitute a casing which serves as a switch circuit unit, the upper casing having at least one hold-down member engaged with the boss to hold down the lead circuit section onto the lower casing,
• wherein a copper foil is formed on the lead circuit section so as to surround the engagement hole.

A method comprising the steps of:

• preparing a flexible printed circuitry including a lead circuit section integrally provided with a switch circuit section, and at three engagement hole are arranged on a lead circuit section in a longitudinal direction thereof with predetermined intervals;
• preparing a lower casing having a side wall provided with a cut out portion from which the lead circuit section is led out, and a boss formed in the vicinity of the cut out portion;
• folding the lead circuit section in an S-shape form such that all the engagement holes are fitted with the boss while providing surplus length portions in order to mount the flexible printed circuitry onto the lower casing;
• leading out the lead circuit section from the cut out portion;
• and
• combining an upper casing having a hold-down member with the lower casing such that the hold-down member engages with the boss to hold down the lead circuit section onto the lower casing.