A keyswitch includes a base having a pillar, a cap having a rib and movable relative to the base, a sleeve rotatably sleeving the pillar and having first and second top surfaces and convex and concave portions, an elastic member abutting against the sleeve and the base, and a resilient arm abutting against a first or second position on the convex portion with rotation of the sleeve. When the resilient arm abuts against the first position, the rib abuts against the first top surface to prepress the elastic member for generating a first preload. When the cap is pressed for moving the sleeve downward, the resilient arm moves from the first or second position to the concave portion. When the resilient arm abuts against the second position, the rib abuts against the second top surface to prepress the elastic member for generating a second preload larger than the first preload.

An exemplary working cylinder for a drive of an electric circuit breaker includes a base that includes a cylinder head and a cylinder body that are connected to one another. Additional components are fastened to the cylinder head as a core piece of the drive, and a thrust ring is guided on an outer surface of the cylinder body. The thrust ring compresses mechanical springs in the mechanical resilient energy storage device by way of a storage piston in a storage module.

When an operation knob 10 formed of silicone rubber is pushed laterally, a stem 7 tilts with a contact portion (i) as a fulcrum, a push button portion 6b is pushed, and a contact point in a switch mechanism portion 6a operates to turn on a switch circuit. Even if, by a large operating force F3 being applied, the operation knob 10 is extended and the inner surface portion 15, which is a ceiling surface of an internal space 13 of the operation knob 10, rides on an upper end portion 7c, a reinforcing surface 19 provided on the inner surface portion 15 slides on the upper end portion 7c, and the operation knob 10 returns to the initial shape.

Push buttons utilizing dome switches are often preloaded to take up any tolerances in the push button design causing a gap and provide consistent tactile feedback to a user. However, conventional push button preload techniques can be costly and difficult to consistently reproduce during push button manufacturing. A new pre-load design does not require pre-depression of the dome switch to close the gap, which permits a more forgiving tolerance to manufacturing variations.

An electronic assembly contains a circuit board having a current-conducting current path with two mutually spaced-apart current path ends that form an interruption point and a contact clip bridging the interruption point. The contact clip is manufactured without a preload, as a thermal fuse. The contact clip has a multiple bent, open clip loop and a contact limb making contact with both mutually spaced-apart current path ends using solder. The contact clip further has a fixing limb with a limb end seated in a circuit board opening. The limb end of the fixing limb is oversized relative to a circuit board opening, and a deformation being imparted to the contact clip, with an internal preload being generated.

A key preloading structure including a base, a set of switches and a set of keys is provided. The set of switches is arranged on the base. The set of keys has a rotating shaft and two actuators. The rotating shaft is assembled on the base. One end of each actuator is fixedly connected to the rotating shaft, and another end is disposed on a switch of the set of switches. Each of the two actuators preloads the set of switches with a force less than a triggering force for starting the set of switches.

A keyboard structure including a base, a frame and several keys is provided. The frame is disposed on the base. The keys are disposed on the base and are separated from each other by the frame. From top to bottom, each key sequentially includes a cap, a limiting structure, an elastic member and a diaphragm switch element. The elastic member is disposed on the diaphragm switch element, the cap is disposed on the elastic member, and the limiting structure is engaged with the cap, such that the cap can move relative to the diaphragm switch element in a vertical direction. The surrounding surface of the cap has a flange, which contacts the bottom of the frame in the vertical direction. Thus, dusts or moisture can hardly infiltrate the keyboard structure and the waterproof and dustproof functions of the keyboard structure can be improved.

A key preloading structure including a base, a set of switches and a set of keys is provided. The set of switches is arranged on the base. The set of keys has a rotating shaft and two extended elastomers. The rotating shaft is assembled on the base. One end of each extended elastomer is fixedly connected to the rotating shaft, and another end is disposed on the set of switches. Each of the two extended elastomers preloads the set of switches with a gravity less than a triggering force for starting the set of switches.

An electronic assembly contains a circuit board having a current-conducting current path with two mutually spaced-apart current path ends that form an interruption point and a contact clip bridging the interruption point. The contact clip is manufactured without a preload, as a thermal fuse. The contact clip has a multiple bent, open clip loop and a contact limb making contact with both mutually spaced-apart current path ends using solder. The contact clip further has a fixing limb with a limb end seated in a circuit board opening. The limb end of the fixing limb is oversized relative to a circuit board opening, and a deformation being imparted to the contact clip, with an internal preload being generated.

An electronic assembly contains a circuit board having a current-conducting current path with two mutually spaced-apart current path ends that form an interruption point and a contact clip bridging the interruption point. The contact clip is manufactured without a preload, as a thermal fuse. The contact clip has a multiple bent, open clip loop and a contact limb making contact with both mutually spaced-apart current path ends using solder. The contact clip further has a fixing limb with a limb end seated in a circuit board opening. The limb end of the fixing limb is oversized relative to a circuit board opening, and a deformation being imparted to the contact clip, with an internal preload being generated.