| 摘要 |
Two embodiments of industrial grade trigger switches are disclosed. Each has an on-off switch and a resistor controlled speed control circuit operated by trigger depression and a reversing switch provided with an operating lever overlying the trigger, and characterized by modular construction with snap-in coupling of reversing switch and base to the frame, a large heat sink area for the solid state current control elements for continuous service, higher current rating double-pole contacts having sufficient wiping action to effect good electrical contact, and the capability of being mounted also in consumer grade tools. The first embodiment has a horizontally disposed substrate that supports the speed control circuit thereby providing a large amount of space within the base for the on-off and shunting contacts. The second embodiment has a large vertically disposed substrate affording a large area for the speed control circuit. The two embodiments differ also in their on-off and shunting switch contacts and their manner of operation, in the heat sink and substrate assembly, in the manner of operating the variable resistor by the trigger, in the reversing switch structure and other details.
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