GB1480494A - Dental matrix - Google Patents

Abstract

1480494 Dental matrices H J LAZARUS 25 July 1974 [26 July 1973] 32825/74 Heading A5R A dental matrix band comprises a flexible strip 10 having an end portion formed into a loop extending from one end thereof, an intermediate portion of the strip slidably overlying the end portion from the edge of which a finger 44 laterally projects, a notch 42 extending inwardly from the outer end of the finger 44, a member 61 extending through the notch 42 and around the overlying portions of the strip to secure the loop and a coil 36 formed by the other end portion of the strip being provided for tightening the loop about a tooth. In use a winding member (88) of a tool (84) forming the subject of Specification 1480495 (see Division B3) is inserted in the coil 36, which when tightened by the member (88) is disposed adjacent the lock-loop 61, and causes tightening of the loop about a tooth and the lock-loop 61 automatically to secure the overlapping portions of the band against relative movement. The loop-forming end portion 18 of the strip is arcuate and has a notch 40 opposite to the finger 44, the notches receiving the lock-loop 61 which comprises a generally U-shaped member disposed around the overlapping portions of the band, one leg 64 of the member having an extension 78 overlapping the free end of the other leg 62. Three arches 70a, 70b, 72 in the outermost leg 64 define ridges 74 which bites into the band as the coil 36 is tightened. The end 12 of the band forming the coil has tapers 30, 32 in its side edges which define in the opposite ends of the coil 36 a socket for receiving the winding member (88) and a concave recess, respectively. The centre of the coil 36 is formed with a trapezoidal notch 24 which is disposed near the end 12 of the band, the portion of the band adjacent the trapezoidal notch 24 thus forming a strut 34 across the coil core joining portions of the band wound in opposite directions. In use, the member (88) as it rotates bears against an edge 26 at the terminal end of the band to tighten the coil 36. After use of the matrix the lock-loop 61 is released by cutting off the finger 44 and the portions of the lock or loop 61 which overlie it using nippers 118 forming the subject Specification 1480497 (see Division B3) which include a shield for receiving the severed portions. Removal of the matrix is facilitated by insertion of a hook in an aperture 38 in the arcuate portion of the band. The coil 36 is formed on a slotted rotatable spindle within a socket in a block forming the subject of Specification 1480496 (see Division B3).