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Bistability as applied in the design of mechanical systems is more commonly said to be "over centre"—that is, work is done on the system to move it just past the peak, at which point the mechanism goes "over centre" to its secondary stable position. The result is a toggle-type action- work applied to the system below a threshold sufficient to send it 'over center' results in no change to the mechanism's state.

Bistability as applied in the design of mechanical systems is more commonly said to be "over centre"—that is, work is done on the system to move it just past the peak, at which point the mechanism goes "over centre" to its secondary stable position. The result is a toggle-type action- work applied to the system below a threshold sufficient to send it 'over center' results in no change to the mechanism's state.

在机械系统中应用于机械系统设计中的双稳态通常被称为“过中心”ーー也就是说，系统所做的工作使其刚刚超过峰值，在峰值处，机构“过中心”到次稳定位置。结果是一个切换类型的动作-工作应用于系统低于一个阈值足以发送它“过中心”的结果没有改变机制的状态。

在机械系统中应用于机械系统设计中的双稳态通常被称为“过中心”ーー也就是说，系统所做的工作使其刚刚超过峰值，在峰值处，机构“过中心”到次稳定位置。结果是一个切换类型的动作-工作应用于系统低于一个阈值足以发送它“过中心”的结果没有改变机制的状态。

[[spring (device)|Springs]] are a common method of achieving an "over centre" action. A spring attached to a simple two position ratchet-type mechanism can create a button or plunger that is clicked or toggled between two mechanical states. Many [[Ballpoint Pen|ballpoint]] and [[Rollerball Pen|rollerball]] retractable pens employ this type of bistable mechanism.

[[spring (device)|Springs]] are a common method of achieving an "over centre" action. A spring attached to a simple two position ratchet-type mechanism can create a button or plunger that is clicked or toggled between two mechanical states. Many [[Ballpoint Pen|ballpoint]] and [[Rollerball Pen|rollerball]] retractable pens employ this type of bistable mechanism.

弹簧是实现“过中心”动作的常用方法。一个弹簧连接到一个简单的两个位置棘轮式机构，可以创造一个按钮或柱塞点击或切换在两个机械状态。许多圆珠笔和滚珠笔都采用这种双稳态机构。

弹簧是实现“过中心”动作的常用方法。一个弹簧连接到一个简单的两个位置棘轮式机构，可以创造一个按钮或柱塞点击或切换在两个机械状态。许多圆珠笔和滚珠笔都采用这种双稳态机构。

An even more common example of an over-center device is an ordinary electric wall switch.  These switches are often designed to snap firmly into the "on" or "off" position once the toggle handle has been moved a certain distance past the center-point.

An even more common example of an over-center device is an ordinary electric wall switch.  These switches are often designed to snap firmly into the "on" or "off" position once the toggle handle has been moved a certain distance past the center-point.

一个更常见的过中心装置的例子是一个普通的电动墙开关。这些开关的设计通常是，一旦切换手柄已经移动了一定距离，超过中心点，就可以牢固地扣入“开”或“关”位置。

一个更常见的过中心装置的例子是一个普通的电动墙开关。这些开关的设计通常是，一旦切换手柄已经移动了一定距离，超过中心点，就可以牢固地扣入“开”或“关”位置。

A [[ratchet (device)|ratchet-and-pawl]] is an elaboration—a multi-stable "over center" system used to create irreversible motion.  The pawl goes over center as it is turned in the forward direction. In this case, "over center" refers to the ratchet being stable and "locked" in a given position until clicked forward again; it has nothing to do with the ratchet being unable to turn in the reverse direction.

A [[ratchet (device)|ratchet-and-pawl]] is an elaboration—a multi-stable "over center" system used to create irreversible motion.  The pawl goes over center as it is turned in the forward direction. In this case, "over center" refers to the ratchet being stable and "locked" in a given position until clicked forward again; it has nothing to do with the ratchet being unable to turn in the reverse direction.

棘轮棘爪是一种精心设计的工具ーー一种多重稳定的“过中心”系统，用来产生不可逆的运动。当棘爪向前方转动时，它会越过中心。在这种情况下，“过中心”是指棘轮是稳定的，“锁定”在一个给定的位置，直到再次点击向前，这与棘轮无法在反方向转动无关。

棘轮棘爪是一种精心设计的工具ーー一种多重稳定的“过中心”系统，用来产生不可逆的运动。当棘爪向前方转动时，它会越过中心。在这种情况下，“过中心”是指棘轮是稳定的，“锁定”在一个给定的位置，直到再次点击向前，这与棘轮无法在反方向转动无关。