A constant force device for a watch

Abstract

The invention discloses a constant force device of a watch. The constant force device comprises a constant power part and an anti-sway part, wherein the constant power part is in engaged connection with an anti-sway gear shaft of the anti-sway part through a driving wheel sheet; and the anti-sway part is used for preventing a positioning wheel sheet of the constant power part from rotation when the torque required by a main spring is smaller than the torque required by a middle spring so as to stop the watch from swinging. The invention has the advantages that: an arresting device is added onthe constant force device, the watch can stop swinging as earlier as possible when a brake wheel is free from the control of a fork tile, namely the middle spring cannot reach the upper limit of preload, the unchanged preload cyclic number of the middle spring is ensured when the watch is wound up again, so relative constant torque corresponding to the elastic force of the middle spring can be ensured to be transmitted to an escape wheel. The structure is simple, the running is stable, and the technique is good, so the constant force device can stably and reliably work.

Description

technical field [0001] The invention relates to a constant force device, in particular to a constant force device through which the force output by the barrel of a watch is evenly transmitted to the escapement speed regulating mechanism of the watch. Background technique [0002] The constant force device of the watch is to transmit a relatively constant torque to the escape wheel, corresponding to the spring force of the middle mainspring. Most of the existing watch constant force devices are an assembly inserted into the transmission, which connects the mainspring and the escape wheel and contains a permanently loaded intermediate spring, in which the spring pretension is always maintained at a small set range , its average value remains constant throughout the working time. Therefore, the change of the state of the mainspring will not change the force applied to the escapement governor, so the vibration frequency of the escapement governor can be more stable; the constan...

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Problems solved by technology

The constant force device of the above structure must ensure that the ratchet is always in contact with the fork of the rocker. When the torque of the mainspring cannot reach the torque corresponding to the upper limit of the pre-tightening force of the middle spring, the ratchet will no longer be affected by the fork of the rocker. control, but at this time, because the middle mainspring can also provide energy for the speed regulating mechanism, the cam is still in the state of normal travel time, and the ratchet and the cam cannot be synchronized periodically. After a certain fork on the lever, when the watch is re-wound, the number of pre-tightening turns of the middle spring will decrease, that is, the pre-tightening force of the middle spring cannot reach the upper limit set, and it cannot be transmitted to the escape wheel during work. The torque corresponding to the spring force of the middle mainspring

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