Patent GB-838563-A (GB)
Title: Apparatus for determining the capability of a person to distinguish between tones separated by a small interval
IPC: A61B5/16
Filed: 1957-12-24
Abstract: 838,563. Testing hearing. YLINEN, K. J. Dec. 24, 1957 [Dec. 27, 1956], No. 40051/57. Class 81 (2). [Also in Group XVIII] Apparatus for determining the ability of a person to distinguish tones separated by a small interval comprises a coin shoot, connected to a labyrinth having at least two exits, and three sound-generating devices, two of which have a higher and a lower pitch respectively than the third. The construction is such that a coin on its way through the shoot causes the third device to generate a tone and, after passing through the labyrinth at random, reaches one of the exits to cause either of the other two soundgenerating devices to generate a tone, there being an arresting device at the exits which is selectively actuable by at least two control members to indicate the person's estimate of the relation between the generated tones. Actuation of any one of the control members causes the arresting device to liberate the coin, the continued movement of which indicates whether or not the person's estimate is correct. As the coin is inserted in a slot 4, Fig. 5, in the casing 1 of the apparatus, it closes a circuit, including a battery 44, Fig. 1, and a coil 37, which causes sudden displacement against a spring 43 of a core 41 of the coil, the core striking a bar 32 to provide a first tone. The coin passes down a shoot 6 and is guided by ribs 10 into a labyrinth comprising a vertical plate 7, Fig. 3, spaced from the casing front wall and carrying horizontal rows of pins 8 which abut the casing front wall. The coin falls at random between the pins and reaches one of three exits 8a, 8b, 8c, formed between the pins of the bottom row, where it is stopped by two contact springs of an upper row 'of pins carried by a plate 14. At the exit, the coin closes a circuit including the battery 44, the two contact springs and a coil 36, 37 or 38 corresponding to the exit reached by the coin. The core of the coil thus energized is displaced to strike one of three bars 32, 33, 34 to generate a second tone of the same, higher, or lower pitch as the first tone. The operator then presses one of three buttons 21, 22, 23 on the outside of the casing, according to his estimate of the relation between the tones generated during the fall of the coin. The button pressed turns a lever 20 against a spring 26 to tilt the plate 14 which is attached to the lever to liberate the coin which then falls through one of three guideways 13 corresponding to the exit 8a, 8b, 8c passed by the coin. As the plate 14 is tilted, contactsprings corresponding to a lower row of pins 16 close the bottom of the guideways 13. The coin is arrested by two of the contact-springs of the lower row of pins to make a circuit through a lamp adjacent the button which the person being tested should have pressed. Lighting of a lamp adjacent a button not pressed indicates that the estimate is incorrect. On releasing the button, the lever 20 and plate 14 return to their initial positions, so that the contact-springs of the lower row of pins release the coin which falls into a box 63.