SU983627A1 - Slide projector - Google Patents

Description

(54) DIAPROEKTOR

one . . ;

The invention relates to a projection technique and can be used in reference information devices, training and controllers, as well as in conjunction with software devices and electronic computers.

Known slide projector with automatic frame change, containing a removable cassette with teeth located on it - Q mi for fixation and drive l, ..

The known slide projector has a large frame change time, and the selection of transparencies in it is carried out manually.

The closest technical solution to the invention is a slide projector containing a removable slide cartridge, kinematically connected to the Drive shaft, and a position sensor of the slide search system 2 J, 20

The disadvantage of the known projector is the large time it takes to search for a slide, since the cassette is stopped at the required position (this is done by electrodynamic braking of the drive motor.

The aim of the invention is to reduce the time of searching for a transparency.

Indicate (the goal is achieved by the fact that the overhead projector provides "1 with a pulsed electromagnetic brake, made in the form of a fixed magnetic conductor and connected to it through a friction pad, fixed on the same shaft with the cassette and the sensor of the search for slides.

FIG. I schematically shows an overhead projector, a common viv; FIG. 2 - pulse electromagnetic brake.

Claims (2)

The overhead projector contains a removable cassette I with transparencies 2, connected by a shaft 3c with a drive pulley 4, a cortex 5 of an impulse electro magnetic brake 6 and a position sensor 7 of the device 8 for transparence search, an electric motor 9, a cassette drive roller O, an non-contact switching signal I, an elecromagnet 12, a retainer 13, which cooperates with the teeth 14 of the cartridge I. The electromagnetic impulse brake 6 (Fig. 2) contains a non-lead magnetic circuit 15, in which a coil 16 is placed, measles 5, connected by means of a diaphragm 17 with a pole 18 y 3, Kogoro mounted in the yoke 15 n bearings 19. Between magnitoprovopom 15 and the armature 5 is mounted on the clutch lining 2O. The diaphragm 17 provides free axial movement of the core 5 and the bealuft transfer of the braking moment to the retractor 18, as well as the absence of a gap between the bark 5 and the magnetic core 15, which ensures the minimum response time of the brake. The coil 16 is connected via a switch II to an electrolytic capacitor (not shown), which provides a high-power pulse, which is necessary for stopping the cassette within a given slide. The overhead projector works in the following way. When the overhead projector is turned on, the electric motor 9 rotates. To find the day of a given slide, its number is entered into the search system 8. If the cassette position does not match the specified one, then the search device 8 sends a signal to switch II, which turns on the electromagnet 12. Electromagnet 12 retracts the latch 13 , frees up the cassette I, and drives the roller 9 of the cassette drive to the shaft of an elegro motor. Cassette I begins to rotate and when it reaches a predetermined position, the search device of the transparency 8 pulls the corresponding signal to the switch 11 which turns on the brake 6 and turns off the electromagnet 12. Brake 6 stops the cartridge I within the specified slide film and turns off, and the latch 13 acts on the corresponding of the teeth 14, brings the cassette I to a predetermined position. After that, the transparency 2 is moved to the projection channel by a transport device (not shown). When setting the next frame, the slide is returned to the cassette and then the cycle repeats. The introduction of a pulsed electromagnetic brake associated with a cassette reduces the search time for the required slide and, thus, changes the technical characteristics of the device. Claims An overhead projector containing a removable cassette with teeth located on it, kinematically associated with a drive shaft, and a position sensor of a slide search system, characterized in that, in order to shorten the slide search time, it is equipped with a pulsed electromagnetic brake, filled in the form of a fixed the magnetic circuit and associated with it through a friction lining of the core, fixed by means of a diaphragm on the same shaft with the cassette and the position sensor of the slide search system. Sources of information taken into account in the examination. I. Patent of Germany No. 2.426.074, cl. GO3 B 23 / ABOUT. 1975. 2. Patent of Great Britain N "1.2 74.981, class, I1K1, (prototype). W