| 摘要 |
An extraoral force-reaction device engageable with the wearer's head and/or neck, such as a headcap or a neckband, is connected to an intraoral force-applying device, such as molar bands, by force-producing means, such as springs. Snapback of the force-applying means is restricted by limiting the normal range of movement of the force-applying elements and such snapback is controlled in response to relative movement of the intraoral means and the extraoral force-reaction means away from each other beyond a predetermined maximum limit, or in response to stressing of the force producing means beyond a predetermined maximum degree of force exerted by the force producing means. Snapback control may be effected by latching of a limit latch to prevent or limit return movement of the force-reaction device and the force-applying device, or disconnectible means can be disconnected to interrupt the application of primary force to the intraoral means and reaction force to the head or neck engageable means. The force to be exerted by the spring force producing means can be readily adjustable in predetermined increments, such as by engagement of different holes in a spring anchor strap with an anchor pin, or by a linear ratchet device. Also, various components of the extraoral force-reaction device can be assembled and adjusted as to length by connection of separable connections, which may include linear ratchet means.
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