Orthodontic traction appliance

An orthodontic traction appliance comprising:

• support means to be worn by a patient having portions which are positioned adjacent the sides of the patient's head as said support means is worn;
• extensions secured to said support means positioned to extend forward adjacent opposite sides of the head as the support means is worn, each extension having a forward end;
• a clasp at the forward end of each extension;
• tension means releasably secured to each extension by the respective clasp each extending forward from the forward end of the respective extension as said support mean is worn;
• each said tension means comprising a strap;
• each said tension means having means at its forward end for attachment to an orthodontic face bow;
• said clasp comprising a body secured to the respective extension at the forward end of the extension having an opening therein through which the respective strap is inserted from the outside with the strap extending forward from the respective extension;
• said clasp further comprising gripping means carried by the clasp body for movement from an open position for insertion into and pull-out of the strap from the opening and a closed position gripping the strap inserted in the opening;
• said gripping means of each clasp being responsive to pull on the face bow to open and release the respective strap if the pull on the strap resulting from pull on the face bow exceeds a predetermined value;
• wherein the gripping means of each clasp comprises a gripper pivoted for swinging movement on an axis transverse to the respective extension and strap at the rear of said opening, said gripper being swingable on said axis to a closed position extending forward toward the front of said opening and holding the strap inserted in said opening against the clasp body at the front of the opening;
• and
• wherein the body of each clasp is formed of sheet metal and comprises a generally flat crosspiece which extends transversely across the respective extension on the outside of the extension at its forward end, a part bent to extend back under the forward end of the extension and to secure the crosspiece to the forward end of the extension, and a pair of arms at the sides thereof extending back from the crosspiece, the gripper of each clasp being pivoted at one end thereof constituting its rearward end for swinging movement on an axis extending between the rear ends of the respective arms, the rearward edge of the crosspiece constituting the forward edge of the opening, each strap being insertable in the opening of the respective clasp body with the strap extending over the crosspiece on the outside of the crosspiece for holding of the strap by the respective gripper against the rearward edge of the crosspiece.