DD137156B1 - slide Projector - Google Patents

Description

Field of application of the invention:

The invention relates to a slide projector with a slide changing device for slides from magazines, wherein the magazine movement can be triggered either forward or backward by means of parallel operating solenoids in the control circuit.

Characteristic of the known technical solutions:

In motorized projectors, it is common practice that to maintain the gear engagement for the movement of the slide changing device for the duration of a change step, a self-holding contact is provided which maintains the switching contact after releasing the Diawechselbetätigungsschalters for a change step duration (an embodiment of this is in the DT-OS 2 245 566). The gear engagement is usually effected by tension magnets, which are arranged in parallel in the circuit and can be incorporated by a direction switch as needed in the circuit.

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This now results in the risk of incorrect operation, by, for example, while maintaining an alternating step forward through the self-holding contact due to an unintentional release of the slide change backwards on the handset faults that can cause the puncture failure result. It has already been attempted to remedy this by using electromagnetically induced mechanical coupling devices, wherein the one direction of movement is blocked by mechanical separation, when a change step is carried out in the other direction

becomes о (eg projectors Braun "Paximat 5000 electronics" and Voigtländer "Perkeo AF Automat" ")

However, this solution requires an increased Teielaufwand and complicated adjustments ₀ In addition, a fast

Switching the coupling devices inhibited by a degree of inertia. Furthermore, no duration pulses are possible for several steps

Object of the invention:

The invention is based on the object to increase the operating safety of projectors with low production and parts costs thereby.

Explanation of the essence of the invention:

In order to achieve this object according to the invention, it is provided that at least one of the two actuation magnets, but preferably both, is preceded by an electronic blocking element which blocks the flow of current through the other actuation magnet for the flow of current through the first-mentioned actuation magnet. is, wherein each locking member is a transistor or a thyristor whose base is connected to the line of the other actuating magnet.

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Embodiment:

The invention is illustrated and described in more detail with reference to two exemplary embodiments. In the drawing show:

Fig. 1 is a diagram of an equipment variant of the first embodiment of the invention

Pig. 2 This embodiment in a different equipment variant

Pig. 3 is the circuit diagram of a Ausstattungsveriante the second embodiment

Pig. 4 this second embodiment in another equipment variant.

As is apparent from Figures 1 and 2, a projector unit I and a manual switch unit II are provided, whose circuit diagrams are shown and which are coupled together. Here are the mutually parallel actuating magnets 1 for the operation of the slide change forward and 2 for the operation of the slide change backwards in the projector unit I.

As trigger elements are in the manual switch unit II of the operation switch 3, which is designed as a rocker switch and coupled to the direction switch 4, and further in the projector, an operation switch 7 is provided, which is held unactuated in a central position between two directional contacts. Furthermore, a self-holding contact 5 is provided which maintains the energization of the corresponding actuation magnet 1 or 2 initiated by the actuation switches 3 and 7 for the duration of a change of the slide. In series with each actuating magnet 1 and 2 is an electronic locking member in the form of a Transi

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stors 8 and 9 or thyristors 10 and 11 connected, whose base is connected to the line of the other actuating magnet 2 and 1, said base lead a ballast resistor 12, 13 _} 14 or 15 and optionally in the transistor embodiment, a diode 16 or 17 may have.

To the network node of the branches of both actuation solenoids 1 and 2 for self-holding contact 5 and the hand switch bridging line from the operating switch 3 to the self-holding contact 5 diodes 18, 19 and 20 are arranged, the forward direction to the self-holding contact 5 has о

Another embodiment is shown in FIGS. 3 and 4. This is a simplified form, somewhat disarmed as compared with the first embodiment, whereby aging is only a matter of incorrect operation. to avoid in an only one direction switching automatic operating switch. This is here in the form of a timer б formed on the projector unit I and there is no operating switch for both directions provided on the projector. In this embodiment, a blocking member is connected as a transistor 8 or thyristor only in series with the actuating magnet 2 for the Rückwärtsdiawechsel whose base is connected to the line of the actuating magnet 1, in which case a ballast resistor 12 or 14 may be provided. The timer 6 is connected only to the actuating magnet 1, ie for the forward direction.

The function is as follows:

In the first embodiment, the operation switch 3 is in communication for one of the two slide changing directions

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with the direction switch 4 on the manual switch unit II or from the operating switch 7 to the projector unit I given a switching pulse, the further sequence for the triggering of the forward direction is described, but applies analogously also for the reverse direction. The actuating magnet 1 is energized and triggers in a known and not shown here manner the slide change forward, the self-holding contact 5 after releasing the trigger switch keeps the contact closed over the full length of a Diawechselschrittes _o Here, the locking member, in series with the actuating magnet 1 and is embodied by the transistor 8 or the thyristor 10, the current flow through the actuating magnet 1 free path, since no barrier effect is exerted.

If now accidentally operated during the slide change process forward reverse v / earth, so is given by the base current at the transistor 8 or thyristor 10, the blocking function of the blocking member for the current through the actuating magnet 2, whereby no malfunction triggered and sustained by self-holding contact 5 Diawechselschritt forward is completely executed. The diodes 18, 19 and 20 are used to decouple the switching signals, while the Vorschaltwiderstände 12, 13, 14 and 15 are provided for the design of the base current, and the diodes 16 and 17 for proper control of the transistors 8 and 9 are required. In a somewhat simplified form, it behaves in the second embodiment. Here, the base current at the transistor 8 or thyristor 10 prevents the accidental release of a Diawechselschrittes backwards when the forward movement is maintained by the self-holding contact 5, the timer б is arranged only for the operation of the forward direction and it depends mainly on it, by the timer 6th controlled device function to make any interference occur.

Claims (8)

1. Slide projector with Piawechseleinrichtung for slides from magazines, the magazine movement can be triggered either forward or backward by means of parallel actuation solenoids in the control circuit ^ and except the operating switches that can be operated by hand directly on the device or s-nsetzoaren manual switch units or remotely controllable or as a timer be designed to maintain the movement of the slide changing device for the duration of a full Diawechselschrittes a self-holding contact, characterized in that at least one of the two actuating magnets (2; 1) is preceded by an electronic locking member, the current flow through the second actuating magnet (1 2) for the flow of current through the first actuating magnet (2; 1) can be blocked. 2. Slide projector according to item 1, characterized in that each of the two actuating magnets (2; 1) is preceded by such a locking member. 3. Diaprojektor according to item 1 or 2, characterized in that the blocking member is a transistor (8; 9) whose base is connected to the line of the other actuating magnet (1; 2). 4. Slide projector according to item 1 or 2, characterized in that the blocking member is a thyristor (10; 11) whose base is connected to the line of the other actuating magnet (1; 2). 5. slide projector according to item 3, characterized in that the transistor (8; Э) in the base lead a 'resistor (14; 15) is connected upstream » - τ- 203388 6. Diaprojektor according to item 4, characterized in that the thyristor (10; 11) in the base supply line, a resistor (12; 13) is connected upstream. - 6 - 203388 Claim for invention 7. Diaprojektor according to item 1, characterized in that around the network node of the branches of both actuating magnets (1; 2) for self-holding contact (5) and the handset bridging line from the operating switch (3) on the manual switch unit II to the self-holding contact (5) diodes (18; 19, 20) for decoupling
are arranged. 8. Diaprojektor according to item 3 and 7 »characterized in that the transistor (8; 9) ^A n of the base lead a diode (16; 17) is connected upstream. For this 2 ropes drawings