Dual-truncated wheel kibble balance and determining absolute mass

Patent metadata

Field	Value
Publication number	US-12546645-B2
Application number	US-202318210033-A
Country	US
Kind code	B2
Filing date	Jun 14, 2023
Priority date	Jun 14, 2022
Publication date	Feb 10, 2026
Grant date	Feb 10, 2026

Abstract

A dual-truncated wheel Kibble balance includes: a stationary frame; a double balance wheel disposed on the stationary frame; a pair of guide members, such that one of the guide members is disposed on each opposing end of the double balance wheel; outer connector bands, such that each guide member is gravitationally suspended from the double balance wheel by at least one of the outer connector bands; inner connector bands, such that each guide member is gravitationally suspended from the double balance wheel by at least one of the inner connector bands; and a central flexural bridge in mechanical communication with the stationary frame and the double balance wheel, such that the central flexural bridge is: interposed between the stationary frame and double balance wheel, interconnects the stationary frame and the double balance wheel, and flexes in response to pivotal motion of the double balance wheel relative to the stationary frame.

First claim

What is claimed is:

1 . A dual-truncated wheel Kibble balance for determining absolute mass, the dual-truncated wheel Kibble balance comprising:
a stationary frame that provides a stationary point of attachment:
for displacement motion of a measurement mass arm and a reference force arm relative to the stationary frame, and
for pivotal motion of a double balance wheel relative to the stationary frame;
the double balance wheel in mechanical communication with the stationary frame at the stationary point of attachment to the stationary frame and that pivots about the stationary point of attachment to the stationary frame, such that the double balance wheel is suspended from the stationary frame by a central flexural bridge that is mechanically interposed between the double balance wheel and the stationary frame, so that the double balance wheel pivotally moves via the central flexural bridge to restore mass balance between the measurement mass arm and the reference force arm, the double balance wheel comprising:
a lever bar disposed on and opposing the stationary frame and in pivotal communication with the stationary frame via the central flexural bridge;
an outer truncated wheel disposed on the lever bar at an outer wheel radius and comprising: a first outer wheel head and a second outer wheel head, such that each outer wheel head comprises an outer peripheral radial surface arranged at the outer wheel radius;
an inner truncated wheel disposed on the lever bar at an inner wheel radius and comprising: a first inner wheel head and a second inner wheel head, such that each inner wheel head comprises an inner peripheral radial surface arranged at the inner wheel radius, and the inner truncated wheel is circumscribed by the outer truncated wheel with the outer wheel radius greater than the inner wheel radius;
the central flexural bridge in mechanical communication with the stationary frame and the double balance wheel, such that the central flexural bridge is: interposed between the stationary frame and the double balance wheel, interconnects the stationary frame and the double balance wheel, and flexes in response to pivotal motion of the double balance wheel relative to the stationary frame; a first outer connector band disposed on the first outer wheel head at the outer peripheral radial surface, such that the first outer connector band is gravitationally suspended from the first outer wheel head and mechanically interconnects the first outer wheel head and a first guide member to synchronize the rotation of the outer truncated wheel and vertical linear motion of the first guide member and constrains motion of the first outer wheel head and the first guide member to one degree of freedom; a second outer connector band disposed on the second outer wheel head at the outer peripheral radial surface, such that the second outer connector band is gravitationally suspended from the second outer wheel head and mechanically interconnects the second outer wheel head and a second guide member to synchronize the rotation of the outer truncated wheel and vertical linear motion of the second guide member and constrains motion of the second outer wheel head and the second guide member to one degree of freedom; a first inner connector band disposed on the first inner wheel head at the inner peripheral radial surface, such that the first inner connector band is gravitationally suspended from the first inner wheel head and mechanically interconnects the first inner wheel head and the first guide member to synchronize the rotation of the inner truncated wheel and vertical linear motion of the first guide member and constrains motion of the first inner wheel head and the first guide member to one degree of freedom; a second inner connector band disposed on the second inner wheel head at the inner peripheral radial surface, such that the second inner connector band is gravitationally suspended from the second inner wheel head and mechanically interconnects the second inner wheel head and the second guide member to synchronize the rotation of the inner truncated wheel and vertical linear motion of the second guide member and constrains motion of the second inner wheel head and the second guide member to one degree of freedom; the first guide member in mechanical communication with the first outer wheel head and the first inner wheel head; and the second guide member in mechanical communication with the second outer wheel head and the second inner wheel head.

2 . The dual-truncated wheel Kibble balance of claim 1 , wherein the first guide member comprises:
a final stage disposed on the first outer connector band; an intermediate stage disposed on the first inner connector band; a plurality of lateral connectors, such that some of the lateral connectors interconnect the final stage and the intermediate stage, and some of the lateral connectors interconnect the intermediate stage and the stationary frame; and a plurality of guide flexural members, such that the lateral connectors interconnect the final stage and the intermediate stage via guide flexural members; the lateral connectors interconnect the intermediate stage and the stationary frame via guide flexural members; the final stage is disposed on the first outer connector band via at least one guide flexural member, and the intermediate stage is disposed on the first inner connector band via at least one guide flexural member.

3 . The dual-truncated wheel Kibble balance of claim 1 , wherein the second guide member comprises:
a final stage disposed on the second outer connector band; an intermediate stage disposed on the second inner connector band; a plurality of lateral connectors, such that some of the lateral connectors interconnect the final stage and the intermediate stage, and some of the lateral connectors interconnect the intermediate stage and the stationary frame; and a plurality of guide flexural members, such that lateral connectors interconnect the final stage and the intermediate stage via guide flexural members; lateral connectors interconnect the intermediate stage and the stationary frame via guide flexural members; the final stage is disposed on the second outer connector band via at least one guide flexural member, and the intermediate stage is disposed on the second inner connector band via at least one guide flexural member.

4 . The dual-truncated wheel Kibble balance of claim 1 , further comprising the measurement mass arm and the reference force arm.

5 . The dual-truncated wheel Kibble balance of claim 4 , further comprising a translational cord in mechanical communication with the first guide member and the measurement mass arm, such that the translational cord is interposed between the first guide member and the measurement mass arm, interconnects the first guide member and the measurement mass arm, and linearly translates the measurement mass arm parallel to earth's gravitational field in response to pivotal motion of the double balance wheel relative to the stationary frame.

6 . The dual-truncated wheel Kibble balance of claim 4 , further comprising a translational cord in mechanical communication with the second guide member and the reference force arm, such that the translational cord is interposed between the second guide member and the reference force arm, interconnects the second guide member and the reference force arm, and linearly translates the reference force arm parallel to earth's gravitational field in response to pivotal motion of the double balance wheel relative to the stationary frame.

7 . The dual-truncated wheel Kibble balance of claim 4 , wherein the measurement mass arm comprises a coil in mechanical communication with the first guide member.

8 . The

Assignees

• Government Of The Us Secretary Of Commerce

Inventors

• El Haddad Darine
• Keck Lorenz Harald
• Theska René Bernd
• Seifert Frank Christian

Classifications

• G01G21/23

  Support or suspension of weighing platforms (G01G21/24 takes precedence) · CPC title

• G01G1/22

  for precision weighing · CPC title

• G01G21/244

  combined with flexure-plate fulcrums (flexure-plate fulcrums G01G21/07) · CPC title

• G01G21/26

  Counterweights; Poise-weights; Sets of weights; Holders for the reception of weights · CPC title

• G01G21/28 Primary

  Frames, Housings · CPC title