Patent GB-1133433-A (GB)
Title: Mouth mirrors
IPC: A61B1/247
Filed: 1966-02-10
Abstract: 1,133,433. Mirrors for medical, especially dental, use. E. ZDARSKY. 10 Feb., 1966 [1 Oct., 1965], No. 5789/66. Heading A5R. [Also in Division G2] In a mirror for medical use, more especially for dental use, comprising a glass piece releasably connected to a frame plate having a shank for attachment of a handle thereto, a metal mounting plate is fixedly secured to one face of the glass piece and is connected ,to the frame plate by a coupling of a construction such that the glass piece and the mounting plate may be released from the frame plate by rotation of the glass piece and mounting plate relative to the frame plate. The mounting plate may be secured to the glass piece either by adhesive or by an ultrasonic weld. In the embodiment illustrated in Figure 1, circular glass piece 1 is provided on one face with a mirror coating 2 and on the other face with an adhesive layer 5 for securing to the glass piece a mounting plate in the form of a disc 6 of plano-convex cross-section and of a diameter slightly smaller than the diameter of the glass piece. In the centre of the disc is a tapped hole 7 threadably and releasably engageable with a screw-threaded stud 8 integral with a frame plate 3 having a shank 4 the free end of which is threaded for attachment to a handle (not shown). The frame plate is arcuate in diametric cross-section, the thickness of the mounting plate varying in accordance with the curvature of the frame plate which is formed at its rim with a narrow pressing edge 9 to provide a seal with the glass, piece. In an embodiment illustrated in Figure 2 (not shown), the mounting plate is extended radially so that the pressing edge of the frame plate seals against the periphery of the mounting plate. In either embodiment, the seal may be enhanced by providing the pressing edge of the frame plate with a plastics covering; also, the mounting plate and the frame plate preferably are separated by an air gap 10. In the embodiment illustrated in Figure 3, glass piece 1 is secured to a mounting plate in the form of a base plate 26 having a screwthreaded stud 28 which is engageable with, a tapped hole 27 provided in a frame plate 23 the pressing edge 29 of which has applied thereto a sealing ring 30 of soft material to provide a seal between the glass piece and the frame plate. In the embodiment illustrated in Figure 4, glass piece 1 is secured to a mounting plate in the form of a disc 36 the edge of which is provided with a screw thread 38 engageable with a screw thread 37 formed on the internal face of the rim of a frame plate 33 which has a pressing edge 39 to provide a seal between the glass piece and the frame plate. In the embodiment illustrated in Figure 5, glass piece 1 has an adhesive layer 40 applied only to a peripheral portion thereof, central zone 42 being free of adhesive; secured by the adhesive to the glass piece is a mounting plate in the form of a flexible diaphragm plate 41 the centre of which carries a screwthreaded stud 48 engageable with a tapped hole 47 provided in a frame plate 43 and the peripheral portion of which has annular ribs 44 engageable with corresponding annular grooves 45 provided in the frame plate. The annular ribs formed on the diaphragm plate may be replaced by arcuate slots separated by intermediate webs which preferably are ribbed; as illustrated in Figures 6 and 7 (not shown), the diaphragm plate is formed with one annular rib, which rib serves to define the adhesivefree central zone, and with two annuli consisting of arcuate slots separated by intermediate webs, the webs of one annulus being laterally staggered with respect to the webs of the other annulus, and the frame plate is formed with a butt edge which extends radially beyond the rim of the glass piece. In any described embodiment, the mounting plate and/or the frame plate may serve as heat reservoir(s).