Patent GB-1421601-A (GB)
Title: Lock spring pin appliance
IPC: A61C7/30
Filed: 1973-01-10
Abstract: 1421601 Orthodontic appliances T P LABORATORIES INC 10 Jan 1973 [19 Jan 1972 5 May 1972] 1419/73 Heading A5R An orthodontic appliance for uprighting teeth comprises a bracket 11, Figure 1 having an arch wire slot 28, Figure 2 and a perpendicularly extending opening 26; a coil spring 20 having an anchoring tail 31 and a lever arm 32; and a pin 21 having a head (38), Figure 3 (not shown) and a tail 37; the appliance being adapted to be assembled on a tooth 14 so that the arch wire slot extends mesio-distally and the opening occlusogingivally, with at least one arch wire 15 extending through the slot, the spring being secured by its anchoring tail to the bracket and having the lever arm coacting with the arch wire to exert a force on the tooth; and wherein the appliance is adapted so that the tails may be inserted through the opening on opposite labiallingual sides of the arch wire to secure both arch wire and spring in place, one of the tails being long enough to extend through the opening and be bent back to secure the pin and the anchoring tail in the bracket. A locking tab (40) is provided on the pin to lock the spring and pin together, and the head (38) seats on the bracket. A hole (39) is provided in the pin head (38) through which the tail of the spring extends, and the lever arm 32 of the spring 20 includes a hooked portion 33 for engaging over the arch wire 15. The appliance is assembled so that the spring tail 31 is on the labial side, and the pin tail 37 on the lingual side of the arch wire 15. The length of the spring tail 31 does not exceed the occlusogingival length of the bracket, and the pin is made of an easily bendable metal, e.g. brass, and of such a length that is greater than the occlusogingival length of the bracket and can be bent over the bracket to lock the pin and spring thereto. An arch wire engaging means in the form of an extension 22 of the pin 21 is provided, the extension 22 being shaped to engage the arch wire following a predetermined tipping movement of the pin in response to the tipping action of the spring. In a second embodiment, Figure 6 (not shown) the locking tab (40) is omitted. In a third embodiment, Figure 7 (not shown) the locking tab (40) is also omitted and incisal extensions (48) are provided on the head (49) of the pin (50) to prevent relative rotation between the pin and the bracket. In a fourth embodiment Figure 8 (not shown) the head (44) of the pin (42) extends through the interior of the spring coils, a locking tab (46) retaining the spring and pin together. In a fifth embodiment, Figure 9 (not shown) the head (55) of the pin (53) extends through the interior of the spring coils and a locking tab (56) slotted at (57) retains the spring and pin together. An extension (58) may be provided on the locking tab (56) to engage the arch wire following predetermined tipping of the appliance. In a sixth embodiment, Figure 10 (not shown) the appliance is similar to the embodiment of Figure 9 except that the locking tab (56) is omitted. In a seventh embodiment, Figures 11 and 12 (not shown) the pin (66) includes a pair of spaced locking tabs (69) which are bent over the coils 30 of the spring 20. An eighth embodiment, Figure 13 (not shown) is similar to the embodiment of Figure 9 except that a generally right-angled slot (76) is provided in the locking tab (75). In a ninth embodiment, Figure 14 (not shown) locking tabs (82) extending from the head (81) of the pin (79) define therebetween slots (83) in which the spring coils 30 are accommodated. In a tenth embodiment, Figure 15 (not shown) the arrangement is similar to the embodiment of Figure 9 except that the spring tail (95) and pin tail (96) are reversed, i.e. the spring tail is on the lingual side of the arch wire slot and the pin tail on the labial side. In the embodiment of Figure 16, the occlusogingival length of the pin tail 125 is about the same as the occlusogingival depth of the arch wire slot and the spring tail 116 is of such a length to be bendable over the bracket to lock the spring and pin thereto (Figure 18, not shown).