DE1116495B - Reversible hydraulic drive for tapes for magnetic recording - Google Patents

Description

efzf κ ?,

Pal Bi. V .. ^ .. /, ii

New

AUz.,

REGISTRATION DATE: OCTOBER 30 E R 1957

NOTICE THE REGISTRATION AND ISSUE OF THE EDITORIAL:

NOVEMBER 2, 1961

The intermittent transport of tapes, e.g. B. made of paper or plastic, from a donor to a receiving supply reel via processing intermediate stations prepares all the larger Difficulties, the greater the belt speeds and the accelerations or decelerations required will. Previously known methods, for example for the transport of magnetic tapes in computing devices, work with electromagnetically operated clutches. To further increase the speed and shortening the start-up time, they are no longer able to do so. The main obstacles are that the ratio is too low from torque to moment of inertia and the intermittent start-up that extends the life of the belt shortened.

The hydraulic drive is, by its nature, suitable for generating shock-free acceleration and afflicted with little indolence. Its application for generating or transmitting torque is known.

The invention relates to a reversible hydraulic drive for strips made of paper or Plastic, especially for magnetic tapes for magnetic recording, in which in series with a a hydraulic drive motor for the tape reel located in a hydraulic high-pressure system Start-stop valve and a reversing valve are located, which in turn are in a hydraulic low-pressure circuit lying control valves are set, and in which the speed of the drive motor through a shunt is regulated, the flow area of which adjusts itself as a function of the diameter of the tape roll.

A magnetic tape recorder * was selected as an exemplary embodiment of the description; in the explanatory Drawings shows ""

Fig. 1 is a view of the device, partially in section, .__ - ^ v

Fig. 2 is a longitudinal section through the device,

Fig. 3 shows the schematic of the hydraulic control and

4 shows a speed and travel time graph.

The device of FIG. 1 shows supply reels 12 and 13 fastened to a frame 11, between which the tape 14 is transported back and forth. This runs on its way from reel to reel via the deflection point 15 into the supply loop 16, is passed by the driven roller 18 under the scanning head 17 and after the second supply loop 19 via the deflection point 20 of the reel 13 (or delivered). The two prismatic chambers for receiving the loops 16, 19 Reversible hydraulic drive
for tapes for magnetic recording

Applicant:

IBM Germany
International office machines
ίο Gesellschaft mbH,

. Sindelfingen (Württ), Tübinger Allee 49

Hugo Anthony Panissidi, Binghamton, N.Y.

(V. St. A.),
has been named as the inventor

are kept at a slight negative pressure; they are on the compensation chambers 22 and the Openings 23 with the pump 2 in connection. Depending on the length of the supply loops 16, 19 are located the openings 21 of the chambers in the range of atmospheric pressure or negative pressure. With the Openings 21 are connected to electrical switches 3 responsive to pressure differences. One such an arrangement is known in connection with conventional belt drives. The sectional view of FIG. 2 shows some further components of the drive according to the invention, namely the storage container 4 for the hydraulic fluid, the reversing and control valves S and 6 as well as the one drive motor .7 for

the coil 12. ': - .: / x. . '

The schematic of the hydraulic control is shown in FIG. 3. Two electric motors 28 and 28 'drive the _: ·; Pressure pumps 29 and 29 ', which the pressure fluid - -. B. oil, suck from the reservoir 30 and press through the filters 33 and 33 'into the feed lines 31 and 32. In the left circle, the filter 33 is followed by a further pump 35 driven by the motor 34. Pressure relief valves 36, 36 'prevent excessive pressure build-up. The first high-pressure circuit fed by line 31 contains the start-stop valve 37, the reversing valve 38 and the hydraulic motor 39 for driving the roller 18. The reversing valve determines the direction of rotation of the motor. When the start-stop valve 37 (as shown) is open, the flow of liquid reaches the engine via the valve 38. Closing the valve 37 blocks the return of the liquid from the motor and gives a

109 737/146

By-pass for the liquid conveyed in line 31 to line 40 free. The spring 37 a holds that Start-stop valve 37 closed in the absence of a control command. The adjustable needle valve 41 in the Bypass line 42 to motor 39 allows the desired motor speed to be set.

The second hydraulic system, the low pressure system, controls the position of the valves 37 and 38. This circuit contains the start-stop valve 43, which by the Armature of a polarized, externally actuated magnet 44 is set and in the same way reversing valve 45 dependent on magnet 46 The line 47 connected to the high-pressure system is fed, with the one for keeping the pressure constant the pressure relief valve 48 and the expansion tank 49 are connected. Lines 50 and 51 connect that Reversing valve 45 of the low pressure system with the reversing valve 38 of the high pressure system, lines 52 and 53 the two start-stop valves 43 and 38. Line 54 is a return for displaced liquid.

Basically just like the drive and control system just described for the roller 18, this is System for driving the tape reels, such as reel 13. Like parts have been given like numerals, however marked with a comma. The magnet 44 'is here controlled by the supply loop Switch 3 actuated. The requirement for constant tape speed can only be met when winding by regulating the engine speed. The motor 39 'is for this purpose a shunt with from Assigned winding diameter-dependent flow cross-section. The lever 58 feels the winding of the bobbin 13 and opens with increasing winding diameter one after the other in its cross-section the needles 57 adjustable flow rates of the regulator 55 by means of the piston 55 a.

When the motor 39 'starts up, the shunt remains blocked until the speed reaches a value has reached about 75% of its setpoint. As soon as this is the case, there is 62 in the return line from the motor, the pressure curve of which can be set with the needle valve 63, to actuate the shut-off valve 59 sufficient pressure which overcomes the force of the return spring 60 via the line 61. When closed Start-stop valve 37 'reaches the pumped pressure fluid from line 32 into the line 64 and back to reservoir 30.

In summary, the mode of operation is as follows: With the solenoid valves 46, 46 'the required Direction of rotation set, this control command from the reversing valves 45, 45 'of the low-pressure circuit transferred to the reversing valves 38, 38 'of the high pressure circuit. An order coming from outside actuates the magnet 44, the action of the pressure switch 3 actuates the magnet 44 '; the position of the start-stop valves 43, 43 'results in the same position of the valves 38, 38'; the roller 18 runs with constant that Coil 13 with a speed dependent on the winding diameter; the speed control of the motor 39 'occurs

ίο only in effect after startup. The reversal of the The direction of rotation is only possible without further measures by actuating the reversing valves 45, 45 '. Guidelines for the speeds and accelerations that can be achieved with the described device Fig. 4 shows inclinations, in which the belt speed at the bottom over time and the feed at the top are applied. After the start signal, the solenoid valve brings a delay of 1.5 ms; then sets the tape movement, which after 2 ms and a feed of about 1 cm, the full speed of 750 cm / s is achieved. 3.5 ms after the start signal, in the example, the recording on the Start magnetic tape. The arrangement takes 4 ms to switch to the opposite direction.

Claims (3)

PATENT CLAIMS: 1. Reversible hydraulic drive for tapes made of paper or plastic, in particular for magnetic tapes for magnetic recording, characterized in that a start-stop valve (37 ') for the tape reel is in series with a hydraulic drive motor (39') located in a hydraulic high-pressure system. ) and a reversing valve (38 '), which in turn are set by control valves (43' or 45 ') in a hydraulic low-pressure circuit, and that the speed of the drive motor is controlled by a bypass whose flow cross-section varies depending on the diameter of the Tape reel adjusts. 2. Arrangement according to claim 1, characterized in that the shunt to the engine remains blocked as long as the engine speed is read from the pressure of the return line of the engine falls below the minimum value. 3. Arrangement according to claim 1, characterized in that the low-pressure circuit from the Return of the high pressure circuit is fed. Considered publications:
German patent specification No. 944 902. For this! Sheet of drawings