US 6,684,712 B2Granted

Measuring instrument for a pressure gauge

AssigneeWIKA Alexander Wiegand SE & Co. KG

InventorsKurt Klein, Detlef Wahl, Heiko Schliessmann, Helmut Berninger, Bernd Friebe, Burkard Meisenzahl

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Abstract

The measuring instrument for a pressure gauge comprises an indicator unit with two plates that bear rotatably an indicator shaft carrying a pinion and that furthermore bear a gear segment. The measuring instrument furthermore comprises a metal Bourdon tube bent into an arc shape, which is soldered on one end to a spring carrier and on the other to a spring end-piece. The spring end-piece is connected to the gear segment such that the displacement of the spring end-piece because of the measurement pressure is transferred to the gear segment. The spring end-piece constitutes a part that is rigidly attached to one of the two plates prior to the Bourdon tube being soldered to the spring end-piece and that is separated from this plate once the Bourdon tube has been soldered to the spring end-piece. During the course of the manufacture of this measuring instrument, the spring end-piece is produced as a part that is securely joined to the two plates. The Bourdon tube is soldered to the spring end-piece while the latter is still rigidly affixed to the plate. It is not until thereafter that the spring end-piece is separated form the plate. Preferably the spring carrier is integral to or attached to one of the two plates. The spring end-piece assumes its target position with greater accuracy with respect to the indicator unit.

Claims15

Dependent claims

A measuring instrument for a pressure gauge comprising:

an indicator unit, including:
a top plate,
a bottom plate, wherein the top plate and the bottom plate are joined to each other and arranged essentially parallel to and distanced from each other,
an indicator shaft, including an indicator pin projecting from the top plate,
a pinion carried on the indicator shaft, and
a gear segment, wherein the indicator shaft and the gear segment are borne rotatably in and between the top plate and the bottom plate and wherein the gear segment includes:
a lever section, and
a toothed section that engages the pinion,
a spring carrier,
an arc-shaped Bourdon tube including:
an interior,
a first end joined to the metal spring carrier through which a measurement pressure can flow into the interior of the Bourdon tube, and
a second end;
and
a spring end-piece
rigidly joined to the second end of the Bourdon tube, wherein the spring end-piece is displaced depending on the measurement pressure applied to said Bourdon tube,
connected to the lever section such that the displacement of the spring end-piece is transferred to the lever section, and
is attached to either the top plate or the bottom plate prior to the Bourdon tube being joined to the spring end-piece and is separated from either the top plate or the bottom plate once the Bourdon tube has been joined to the spring end-piece, wherein the either top plate or the bottom plate comprise a plate to which the spring-end piece is attached prior to separation.

15 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/887,786Filed 21 Jun 2001 · division
Priority: EP 98 113 93824 Jul 1998
Published: US 2001/0029787 A118 Oct 2001
Granted: 3 Feb 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G01L 7/043
In the form of flexible, deformable tubes, e.g. Bourdon gauges: with mechanical transmitting or indicating means
G01L 7/041
In the form of flexible, deformable tubes, e.g. Bourdon gauges: construction or mounting of deformable tubes
Y10T 29/49789
Method of mechanical manufacture: obtaining plural product pieces from unitary workpiece
Y10T 29/4987
With prestressing of part: elastic joining of parts