Variable-speed control assembly for electric device

Abstract

A variable-speed control assembly for an electric device includes: a housing; a speed signaling circuit module located within the housing including a pair of spaced-apart stationary contact members and a movable contact member configured for movement between at least one of an OFF position in which the movable contact member does not electrically connect the pair of stationary contact members, and, a plurality of ON positions in which the movable contact member electrically connects the pair of stationary contact members; wherein the movable contact member includes an elastically-deformable material configured for deforming in to a plurality of different deformed configurations when arranged in each of the plurality of ON positions such that a contact area between the movable contact member and the pair of stationary contact members will vary in each of the plurality of ON positions resulting in an amount of electrical resistance across the movable contact member varying; and whereby said speed signaling circuit module is configured for producing different output electrical signals configured for use in controlling speed of operation of the electric motor.

Description

technical field [0001] The present invention relates to a variable speed control assembly for controlling the operating speed of electrical equipment or appliances such as power tools, electric garden tools and the like. Background technique [0002] Certain electrical devices and appliances, such as power tools, include an electric motor and a variable speed control assembly including, for example, a variable speed trigger assembly actuatable by a user's finger to control the speed of the motor. When the control assembly is operated, the actuator shaft can be displaced, and the degree of displacement can be sensed and processed by the speed signaling circuit as a basis for variably controlling the speed of the motor. In some existing control assemblies, the actuator shaft may typically need to move over a distance of about 4mm to 10mm, and the actuator shaft will be operatively connected to a biasing element such as a return spring, The biasing element urges the actuator s...

AI Technical Summary

Problems solved by technology

Another problem associated with certain existing control assemblies, such as those that include trigger assemblies, is that existing control assemblies tend to utilize many interconnected moving mechanical parts, which increases susceptibility to wear durability and incur higher maintenance and repair costs over time

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