DE7330144U - Inclination scale with taring device - Google Patents

Description

Mettler Instrumente AG, Greifensee (Switzerland)

Inclination scale with taring device

The invention relates to an inclination balance with a balance beam, with a parallel guide acting on this Tray carrier, with a device for detecting and / or displaying the beam deflection and with at least one two springs comprising the buoyancy compensator acting on the buoyancy compensator, the springs in opposite directions Act on the shell support in vertical directions.

This known balance has the advantage of a largely linear characteristic curve of the effective spring forces, as it is characterized by the counter-rotation of the spring extension mutually cancel out the square components of the nonlinearities. It this results in a largely stabilized sensitivity

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of the balance, which is largely due to minor deviations of the balance position from the horizontal (leveling errors) preserved.

On the other hand, remains at üex. got an im = rkIie influence the zero point of the balance exist even with minor leveling errors. To eliminate this, was already proposed for scales with spring taring and optical reading of the weight-dependent inclination of the balance beam an additional pendulum carrying parts of the projection optics to be provided, which is acted upon by an additional force (for example by means of a magnet arrangement) which causes approximately a synchronous deflection of the balance beam and the additional pendulum when the balance is inclined. This largely avoided reading errors caused by slight inclinations of the scales. A disadvantage of this arrangement however, is the high effort.

The object of the present invention was to provide a level change with significantly simpler means To create similarly insensitive scales (leveling errors). According to the invention, this object is achieved in that in a scale of the type mentioned, one of the springs on the fixed part of the scale and on the pan support and one Another spring is attached to the shell support and a height-adjustable tensioning member.

The arrangement is preferably such that the resulting spring force acting on the shell support

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on the shown • I · t »· ·
I · It ··
, I.
It lit
,,. - · · " . · '' · " ³ " b
. . · W is equivalent to. modification Weight value of the .ehkeit u Inclination range at least approximates that with this arrangement How yourself Slope range W == "= as far as stSi? Ilisier? ¹ !!; has, let yourself r.a zero point of

that the deviations with an inclination of 2 o / oo only make up a maximum of about 0.2 o / oo of the optical range. However, the zero point deviations are dependent from pulling out the taring springs, slightly asymmetrical. According to a further development of the Invention can be eliminated in that the resulting change in the spring force acting on the shell support is somewhat greater is than the weight value of the slope range. In other words, the spring constants are increased so that the The proportion of spring force varies from zero to full deflection of the balance beam changes by a little more than 100% of the slope range.

In the practical implementation of the taring device, it has proven to be advantageous that the on the shell carrier acting spring forces are applied by two springs, the spring constants of which are roughly 2: 1.

An exemplary embodiment of the invention is described below with reference to the drawing, the selected balance was shown schematically in side view. The balance comprises a base plate 1, one of which is a column 2 towers. A main bearing 3 of a balance beam 4 is arranged on the column 2. At its free end (counterweight =

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end) the balance bar 4 has a scale 5 provided with characters and numbers, which is shown in sections by means of a projection device on a ground glass in the housing (the last-mentioned components are consistently conventional and are not essential for understanding the present invention, which is why their representation was waived). At the other end of the balance beam rests on an external bearing 6, a shell carrier 7. This has a scale pan 8 at the top and a blade bearing at the bottom, in which a link 10 engages, which at its other end in a further blade bearing Ia. rests on column 2. The shell carrier 7 is thus guided in parallel.

With the upper part of the tray support; 7 is firmly connected

a Z-like boom 12. At its upper one Part engages a Zugfodar 13, which is fastened at its lower end in a stationary bracket 14. A second tension spring 15 is on the one hand; attached to the lower part of the boom 12, on the other hand to a traveling nut 16. The latter engages around a guide column 17 and can be moved vertically by turning a screw 18. The screw 18 has a knurled control button 19 at the top; at the bottom it can be rotated, but axially fixed, caught in a fixed arm 20 extending from the guide column 17.

Depending on the circumstances and requirements, the tension springs have 13 or 15 at one or more of their clamping points

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Adjusting devices for setting the spring extension and / or for producing an exact vertical alignment on; Furthermore, one or both of the springs can have a screw head for adjusting the spring constants by stopping them contain a corresponding number of turns. These conventional adjustment means are not shown in detail.

Furthermore, the representation of shift weights arranged in a known manner and their operation was also emphasized waived.

While the springs in known arrangements were dimensioned in such a way that the resulting changes in force exerted by them on the pan support only corresponded to about 15% of the optical range (inclination range), a resulting change in spring force of about 101 % of the inclination range is set in the present balance . The spring 13 supplies a force component of approximately 70%, the spring 15 a force component of approximately 30%, ie the spring constants behave approximately like 2: 1. Choosing a smaller .Federkonstante for the spring 15 has the advantage that dw ζ any * inaccuracies in the manufacture and / or assembly of the adjustment mechanism (16-20) have a far less pronounced effect on the Ι accuracy of the balance than is the case with arrangements

is the case with springs with the same characteristic.

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Claims (4)

'Protection claims 1. Inclination balance with a balance beam, with a parallel- guided shell carrier acting on this, with a device for detecting and / or displaying the beam deflection and with a taring device comprising at least two springs ^ acting on the shell carrier, the springs in opposite vertical directions on the Acting neck support, characterized in that one of the springs is attached to the fixed part of the balance and to the pan support and another spring is attached to the pan support and a height-adjustable tensioning member. 2. Inclination balance according to claim 1, characterized in that that the resulting change in spring force acting on the shell support over the inclination range at least approximately corresponds to the weight value of the inclination area. 3. Inclination balance according to claim 2, characterized in that the resulting change in the spring force acting on the shell support is slightly larger than the weight value of the incline area. 4. Inclination balance according to claim 1, characterized in that that the spring forces acting on the shell support are applied by two springs, their spring constants behave like 2: 1. 73301A429.11.73