# US 4,393,725 A · Apparatus to measure yarn tension

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- Number: US 4,393,725 A
- Document ID: US4393725A
- Status: Granted
- Kind: A
- Application number: 06/236,966
- Filed: 1981-02-23
- Granted: 1983-07-19
- Earliest claimed: 1981-02-23
- Assignees: Milliken Research Corporation
- Inventors: Larry S. Satterfield
- Web page: https://patentgrep.com/patent/US4393725A

## CPC

- G01L 5/042: {by measuring vibrational characteristics of the flexible member}
- B65H 59/40: Applications of tension indicators
- G01H 13/00: Measuring resonant frequency
- B65H 2511/52: Defective operating conditions
- B65H 2557/61: for calibrating
- B65H 2701/31: Textiles threads or artificial strands of filaments
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)
- B65H: HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES

## Abstract

Apparatus to cause a running length of yarn to vibrate at its harmonic frequency and to electronically measure the harmonic frequency thereof to provide a signal which can be employed to maintain and/or correct the parameters of the system to maintain a desired tension in the yarn being run.

## Claims

### Claim 1

Apparatus to measure the tension in a running length of yarn comprising: a frame, at least one pair of guide members attached to said frame and longitudinally spaced from one another to guide yarn from one end of said frame to the other end of said frame, means mounted to said frame to supply air under pressure against the yarn passing between said guide members to cause said yarn to vibrate at its harmonic frequency and a second means mounted in said frame to measure the harmonic frequency of the yarn as it passes through said guide members, said second means including a U-shaped detector through which the yarn passes and means to allow adjustment of said U-shaped detector relative to the yarn passing therethrough.

### Claim 2 (depends on 1)

The apparatus of claim 1 wherein said means to supply air is an air jet located adjacent said second means.

### Claim 3

Apparatus to measure the tension in a running length of yarn comprising: a frame, at least one pair of guide members attached to said frame and longitudinally spaced from one another to guide yarn from one end of said frame to the other end of said frame, air jet means mounted to said frame to supply air under pressure against the yarn passing between said guide members to cause said yarn to vibrate at its harmonic frequency and a second means mounted in said frame to measure the harmonic frequency of the yarn as it passes through said guide members.

### Claim 4 (depends on 3)

The apparatus of claim 3 wherein said second means includes a U-shaped detector member through which the yarn passes.