DE1263841B - Pneumatically working buffer chamber, preferably for magnetic tape devices - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Gilb

German class: 21 al - 37/38

Number:
File number:
Registration date:
Display day:

S92598IXc / 21 al
August 12, 1964
March 21, 1968

In data processing technology, large amounts of information are often to be recorded or reproduced. Among other things, high-speed magnetic tapes of great length are used as recording media.

The inert mass of the tape lap to be driven cannot be accelerated fast enough, brake or change direction. Therefore, there is often only a short section, which is guided through buffer chambers of the magnetic tape is driven by means of a drive roller, and it is by means of a the Monitoring the filling level of the buffer chambers and the motors for driving the down or the Take-up reel-acting control system ensured, that the tape between the chambers and the tape winding is fed or discharged at the correct speed, so that there is always a corresponding one Tape supply is available in the chambers.

A much-used buffer chamber for tape storage devices works pneumatically. The tape is hanging. Via pulleys in the buffer chamber up to about Half in. Normal air pressure prevails above the belt loop, below the belt loop negative pressure maintained by suction. This will pull the loop of tape into the chamber. This pneumatic tensile force always adapts to the external tensile force exerted by the belt drive roller is exercised, and thus keeps her balance. In this way, the magnetic heads can adjacent section of the belt in the chambers accelerated particularly quickly on their own or be braked without large fluctuations in the due to the inertia of the tape winding Band tension occur. This is an important advantage of using such buffer chambers.

The filling level is also monitored pneumatically in these buffer chambers. to For this purpose, a continuous longitudinal slot is made in the rear wall of the chamber, which is connected to the pneumatic monitoring system is connected. The monitoring system provides through this Slit through different air pressures depending on how high the loop of tape is in the chamber stands. If it is low, an air pressure is determined that is almost the same as the external air pressure. Is the If the tape loop is high, then the slot portion connected to the negative pressure space is large, and a negative pressure is detected that is almost as large as in the negative pressure space. To achieve A control characteristic that is as linear as possible, however, is one that goes right through the rear wall of the chamber Longitudinal slot unfavorable.

Pneumatically working buffer chamber,
preferably for magnetic tape recorders

Addendum to the patent: 1175 021

Applicant:

Siemens Aktiengesellschaft, Berlin and Munich, 8000 Munich 2, Witteisbacherplatz 2

Named as inventor:

Werner Weiß, 8Q0Q Munich - ^

In the buffer chamber. According to the main patent is therefore only a narrow groove-shaped slot in the rear wall of the chamber instead of the continuous longitudinal slot Well provided, from which the connection to the Monitoring system is established. By doing it by distributing these holes or Has cutouts in the hand, as linear as possible To produce control characteristics is the use of bores or millings to the continuous Longitudinal slot in the rear wall of the chamber is preferable. The best possible distribution of these holes or millings were found on the basis of tests. The total area becomes quite general the openings at the top and bottom of the rear wall of the chamber are larger than in the middle made by arranging more openings per unit of length at the top and bottom than in the middle. This purely empirical opening distribution now has the disadvantage that it is disproportionate to a great effort and time is involved. The object of the present invention is a buffer chamber in which the opening distribution on the rear wall can be easily determined. This is achieved in that the opening distribution is given by

a L.

(L-xf

(L - xf + χ ²

if L is the length of the buffer chamber, χ is the length of the tape loop and α is the specified distance between the openings, measured from the same reference

809 519/459

point, and if P _{x is} the pressure drop over the length χ and P is the pressure drop over the entire length of the buffer chamber.

The derivation of the formula is based on the following relationships: Tests have shown that the Air flow through the narrow groove-like recess and the bores (cutouts) essentially is turbulent. So it applies ....

IO

further

+ Pl ^ x = P

Qx = Ql-x

where P _L _ _{X is} the pressure drop in the lower part of the buffer chamber and Q _x or Q _L _ _{x is} the amount of air flowing through the recess in the rear wall of the chamber.

So you get first

Qx =

JC ²

x *

Qx

tional to let grow with the chamber length. This would mean that such large ¹ steps would occur in the control characteristic that the discontinuities would make them unpleasantly noticeable. The hole spacing should therefore not be greater than approximately -20 mm. In addition, "it is possible to correct the hole spacing in such a way that a linear control characteristic is obtained even when using a non-linear measuring device. -> - <

Claims (3)

Patent claims: 1. Pneumatically working buffer chamber, preferably for magnetic tape devices, in which the Monitoring of the level by means of a pneumatic-capacitive Transducer, which is connected to openings passing through the chamber wall, according to patent 1175 021, characterized in that the opening distribution is given by and after a further transformation the formula given above. ■ This formula for calculating the opening distribution has the advantage over the empirically found distribution that it can be used for buffer chambers of any length. In order to achieve a continuous control characteristic even with longer chambers, it is not sufficient to set the hole spacings propor a L (L-xf (L- x if L is the length of the buffer chamber, χ is the length of the tape loop and α is the specified distance between the openings, measured from the same reference point, and if P _{x is} the pressure drop over the length χ and P is the pressure drop over the entire length of the buffer chamber. 2. Buffer chamber according to claim 1, characterized in that characterized in that the individual openings have the same areas. 3. Buffer chamber according to one of the preceding claims, characterized in that the greatest distance of the openings from each other is at most 2% of the row of holes. 809 519/459 3.68 © Bundesdruckerei Berlin