GB829517A - Time delay control device for tissue processing machines - Google Patents

Abstract

829,517. Preparing microscope specimens. TECHNICON INTERNATIONAL Ltd. March 21, 1958 [April 8, 1957], No. 9225/58. Class 97(1) [Also in Group XXX] In automatic immersion apparatus for the preparation of histologic tissue for microscopic examination of the kind in which provision is made for a twenty-four hour clock-controlled timing cycle, a time delay control device is provided which can be set to introduce a delay period prior to the start of the processing cycle or during it. This device may be controlled by the clock mechanism which controls the processing operations. This clock operates continuously and its working is not interrupted by the operation of the time delay control device. The immersion apparatus 10, Fig. 1, is driven by an electric motor 18, Fig. 8, which is controlled by clock timing mechanism 20 comprising a conventional electric clock motor 24, Fig. 3, which rotates a twenty-four hour timing disc 26 and a disc 104 carrying a cut-off pin 128. The motor 24 drives also a time delay control device 32 which delays the start of the processing operation for a predetermined time. The clock-driven shaft 30 is connected by gears 34, 36 having e.g. a ratio of 1 to 3 to a gear 46 of the same size as the gear 36 which is free on a shaft 48. This shaft extends through a panel 22 and is secured thereto by nuts 50, 52, Fig. 3. It is provided with a flange 54, which bears against the hub 56 of the gear 46, and a cam disc 60 which is maintained by the lock nut 62 in relatively tight frictional engagement with a spring spider 58 placed between it and the gear 46. A depression 64 in the disc 60 receives a roller 66 mounted on a normally closed master switch 68. A dial 79 calibrated in hours fits loosely on the shaft 48 and is fixed to the front of the panel 22 by means 80 which acts also as a stop for a knob indicator 82 fast on the shaft. The disc 26 has notches 108 in its periphery to provide determined time sequence of operation of the motor 18 and is marked with intervals of ten minutes. The motor is controlled by a pivoted arm 112 carrying a pin 110 which rides on the periphery of the disc 26 and moves in and out of the notches 108. The arm 112 is in contact with the operation element 124 of a microswitch 116 in the circuit of the motor. The lever 74 carrying the roller 66 is provided with a cross-piece 78 which bears on the underside of a pivoted rocking lever 138 and raises it from the position shown in Fig. 5 to that shown in Fig. 8 as the disc 60 rotates. In the former position, the pin 110 is engaged by a notch 142 in the lever and is prevented from moving into the notches 108. There is, therefore, no delay setting to delay the operation of the apparatus. A pin 136 is provided on the lever 138 for moving it by hand. A cut-off arm 126 is pivoted at 129 on the panel 22 and is moved by the pin 128 on the disc 26 to engage the pin 110 and thereby discontinue the processing operation. Specifications 697,162, 752,484 and 780,793 are referred to.