DE1957177A1 - Device for lifting a stack of sheets - Google Patents

Description

Patent attorneys Dipl.-Ing. F. Weickmann, '

Dipl.-Ing. H.Weickmann, Dipl.-Phys. Dr. K. Fincke Dipl.-Ing. F. A-Weickmann, Dipl.-Chem. B. Huber

8 MUNICH 86, THE SBHA POSTBOX 860 820

MÖHLSTRASSE 22, NUMBER 48 39 21/22

XEROX CORPORATION, Rochester, ΙΊ.Ί. 14603, 7th St.Ao

Provision for lifting a stack of sheets

The invention relates to a device for lifting a stack of sheets to a predetermined height. It is used For example, to hold the top sheet of a stack at this predetermined height so that the sheets can be conveyed away one after the other.

In the case of continuously and automatically operating electrophotographic reproduction machines in the UoS. Patent 3 301 126 as well as in other machines in which sheet material from a stack is conveyed away, is a device for holding the top sheet of a stack in a predetermined Height required. It holds the top sheet in each case at the height that is favorable for its removal from one another Feed Mechanism ", More Complicated Sheet Feed Devices, working at high speed require precise alignment of the top sheet of a stack to close conveying gaps and double conveyances avoid"

A device for maintaining the height of a stack

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on a predetermined value is described in the patent mentioned above · It works with a swiveling sensor rail, which is above the stack of sheets is arranged in such a way that it can be pivoted slightly when the stack is in the predetermined position. Hit the sensor rail is an actuator of one Switch can also be swiveled, where a drive motor for the stack movement can be switched offa The sensor bar moves while the sheets are being used down and maintains contact with the next top sheet · When a given consumption of sheets is reached due to a reinforced swiveling of the sensor rail the switch is actuated and the drive motor is switched on again. It works until the sensor bar swivels again due to the upward movement of the stack and so that the motor is switched off · In this way the stack remains at its predetermined height stand·

Although such a device meets the basic requirements placed on it, it must, however, for an exact function a stepper motor can be provided, which can be stopped quickly when its supply current is switched off Such a motor contains a rotor consisting of permanent magnets and a stator in which the alternating current supplied causes the rotor to rotate in steps. Such a motor has the property of stopping itself automatically · However, it is usually very expensive · Commercial application of the device described in the cited patent requires one slow-running synchronous motor, the rotation direction of which can be electrically reversed, for example a motor of the Type SS-15O-1O77 from Superior Electric Co., Bristol,

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Connecticut. The usual cheaper induction motors are not suitable as they are used when the power is switched off Tend to continue running · After switching off the stator current the rotor continues to run until its load «· is balanced by the various internal losses. In the known device there is also a common one Induction motor can be used, however, in order to maintain accurate stepping, it must be unacceptably less Speed operated so that its initial inertia is quite low

The object of the invention is to provide a lifting device with a cheaper motor. can perform a lifting movement in a short time · .For a device of the type mentioned above, this object is achieved according to the invention in that an electric motor generating the lifting movement is in a first control circuit for rapid movement with alternating current, in a second control loop circuit for slow movement pulsating direct current can be switched and that a sensor that can be actuated by the lifting movement is the first control circuit in the event of a rapid lifting movement switching off and switching on the second control circuit as well as when the predetermined level is reached acts on a second so-holder that switches off the electric motor

With the device according to the invention, a stack of sheets is raised at high speed when approaching the speed is reduced to the predetermined height, and the stack of sheets is at the predetermined height shut down · The device is also suitable for periodically lifting a stack of sheets when its height

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reduced by requesting the top sheet in each case will. Due to the special type of control and supply of the drive motor, a cheaper motor can be used than are used in known devices. «The stack of sheets can be increased at extremely high speed. can be raised and lowered, whereby the, for example, by changing or re-inserting sheet material caused downtime is kept to a minimum. There are no problems with the quick lifting an exact end position, as the motor switches to a lower speed when this end position is approached becomes ρ

An embodiment of the invention is described below with reference to the figures.

Pig. 1 is an illustration of a sheet conveying mechanism, to which the device according to the invention is assigned,

Pig 2 shows the side view of the arrangement shown in FIG. Pig 3 the section 3-3 from Pig.1,

Pig, Figure 4 is a perspective view of one in Pig * 2 and 3 switch shown with actuating arm and

Pigo5 the electrical circuit diagram of the according to the invention provided control circuit

In the figures, a stack of sheets 10 is shown, des-

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sen top sheet 12 with a sheet conveying mechanism 14 is to be conveyed away · This contains suction tubes 16, which feed the respective sheet to the transport rollers 18 · The stack of sheets is arranged on a fish 20 »des ·« sen rollers 22 run in vertical guides 24 and a Raising and lowering the stack relative to the suction » enable pipes · The table is provided with a wire rope 26 which is guided over a pulley 28. This is rotatably mounted on the axis 32, which is arranged in one of the side frame parts 34 of the overall bracket The side of the axle 32 facing away from the roller 30 carries a gearwheel 38 which is connected to the rotor 40 of the motor 42 connected Sohneoke 36 acted As a motor, the Type MG 1 »34 RIi are used, an 8- * pole, reversible, permanent capacitor shaded pole motor Boding Eleotrio Company. The rotation of the motor 42 in Counterclockwise the gear 38 and with it the roller 28 rotates so that the stack of sheets is lowered · One Rotation in the opposite sense causes a corresponding rotation of the roller 28 and thus a lifting of the Stack of sheets on the table 20

Above the point at which the top sheet of the stack is requested in a horizontal direction, "a U-shaped sensor rail 44 is arranged. It is rotatably mounted on short sections 46 and 48, which are arranged coaxially to one another in the side frame parts 34" The attachment 48, which lies on the motor side of the device, protrudes through the frame part 34 and is provided at one free end with a holder actuation arm 50 which can be pivoted with the sensor rail 44. This arm is provided with a spiral spring 52 on "one" of a Saide 54. The other end of the spring is a pin 56

fastened in the machine frame so that the spring biases the holder actuation arm into its lower rest position the stack of sheets lying on the Tisoh

Associated with the end 54 of the holding arm 50 are two limit switches 6LS and 1OLS which are actuated by the arm. A flat part 60 at the end of the arm touches the pinger of switch 1OLS while an im Arm provided adjusting screw 58 touches the actuator of the switch 6LS. Both holders are arranged in relation to the actuating arm in such a way that they duroh the counterclockwise to its one extreme position brought arm (Pig · 3) to be closed · Swiveling the actuating arm clockwise as you duroh the movement of the leaves against the sensor rail is caused by a return movement of the adjusting screw 58 from the finger of the switch 6LS, so that this switch is opened · One more rotation of the arm then causes a release of the switch 1OLS, so that this also comes into its open rest position

The end of the actuating arm facing away from the switches can be provided with a hook arrangement. Like in the is described above, the PUhlersohiene can thereby be requested from the respective The top sheet of the stack can be lifted off.This does not affect holding operations, as the switches are open during sheet feed.

The control circuit shown in Pig 5 will now be used sohrieben · If you see the stack of sheets after actuation d ·· Down · «holder · SV-6B in a different position, see above the lower limit holder 9 LS through the Tieoh g -

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kept open so that the two windings of the motor 42 for upward and downward movement no current is drawn » will lead.

To move the table up, the SW-6A switch must be operated to allow current to flow through the Contacts 3 CR-1B, 6 LS and 10 LS allow that due to the movement of the sensor rail and the switch · * actuating arm in a counter-clockwise direction or · due to the effect the tension spring are closed · This feeds alternating current to the upward winding of the motor, see above that this the sheet stack via the screw 36, the gear 38 and the roller 28 in * a sheet feed enabling situation moved upwards "

If the stack of sheets touches the sensor rail 44 for the first time, so this is moved close up until the holder 6 LS is opened. This causes the current to flow through the rectifier SR-3 conducted, which a one-way rectified pulsating direct current through the closed Sohalter 10 LS supplies to the step-up winding of the motor. The motor fed with such a current rotates at an extremely reduced speed, correspondingly slowly the table is raised · This movement takes place until the stack of sheets and the sensor rail one Have reached the height in which the actuating arm rom switch 10 LS is moved away. At this point, the So holder 10 LS opened so that the upward winding of the Motor is switched off · The self-locking τοη As in the above-mentioned known arrangement, the Sohneoke and the toothed wheel prevent downward movement of the stack of sheets with the table

During operation, the table can run at a motor speed of

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720 / min can be increased with Weohselstrom feed · By switching to pulsating direct current, an electrical braking effect is exerted on the rotor, as a result of which a speed of 15 / min results, which is practically less than 1OjS of the initial speed. hit With this slow motor rotation, the motor can be stopped at an altitude at which the blades are reliable can be promoted. A practically achievable height value is the precisely specified height plus or minus approx.0.5 mm, corresponding to the thickness of 6 to 8 sheets of paper.

While the sheets are being requested from the stack the effective height of which is continuously reduced · If several sheets have been removed, the! Swiveled downwards, whereby the switch 10 LS only is closed. As a result, pulsating direct current is supplied to the step-up winding of the motor, so that this raises the stack again at low speed until the specified height is reached o This process repeats itself as long as there is a sufficient amount of leaves on the table

Should the stack of sheets be used for any purpose, for example To enter a different sheet size, all you have to do is press the down switch SW-6B will. This switches off the upward winding of the motor. The relays 12 CR and 5 CR can respond, contact 12 CR-1 is closed and produces alternating current via the Sohalter 9 LS for the downward winding of the motor. The engine rotates at high speed and causes a rapid lowering of the stack of sheets. When the table reaches its lowest position, the border

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switch 9 IS opened and thus the downward movement of the The motor is switched off, which brings the table to a standstill

Dem.Tisch is also a limit switch 4LS for low Allocated paper supply · If the number of sheets on the table is very much reduced, the table will be higher raised as desired · The normally open contact 4 IS is is closed and switches on relays 12 CR and 3 CR. Contact 3 CR-1B is opened, contact 3 CR-1A closed. Thereby the upward winding of the Mo « shut off. The contact .12 CR-1 closes and supplies alternating current to the downward movement of the Motor, without actuating the down solenoid SW-6B.

The invention has been described above on the basis of a specific exemplary embodiment, but is based on this not restricted · All possible embodiments within the scope of the following claims are encompassed by the basic idea of the invention.

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Claims (1)

Claims Device for lifting a stack of sheets to a predetermined height, characterized in that a . the electric motor (42) generating the lifting movement in a first control circuit for rapid movement with alternating current, in a second control circuit is switchable for slow movement with pulsating direct current and that a through the Lifting movement actuatable sensor (44) to a first control circuit, in the case of a rapid lifting movement, the first control circuit switching off and the second control circuit switching on switch (6 LS) as well as with Reaching the predetermined height on a second switch (10 LS) that switches off the electric motor * works 2. Device according to claim 1, characterized in that the sensor (44) moves and the second switch (10 LS) is closed again when sheets are removed from the top of the sheet stack (10) «, 3. Device according to claim 2, characterized in that that the first and the second switch (6 LS, 10 LS) are connected in series and that the second control circuit is in parallel with the first switch (6 LS) switched rectifier (SR-5) forms 009823/1331 Blank page