Force sensor for measuring static and dynamic friction coefficients

Patent metadata

Field	Value
Publication number	US-11435244-B2
Application number	US-201716767139-A
Country	US
Kind code	B2
Filing date	Nov 30, 2017
Priority date	Nov 30, 2017
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A friction force sensing system comprising one interrupter with a blocking extension and one flexible assembly having a fixed end and a free end, longitudinal flexures extending between said fixed end and said free end, said interrupter and said flexible assembly being fixedly connected to each other by a mounting element at the free end of said flexible assembly.

First claim

What is claimed is:

1. A friction force sensing system comprising one flexible assembly having a fixed end and a free end, two symmetrical longitudinal flexures extending between said fixed end and said free end, with a mounting element at the free end of said flexible assembly, said friction force sensing system further comprising a sensor unit in connection with said flexible assembly in the manner that a free end of said mounting element provides a force application point for the measurement of friction forces, wherein
a slot extends from free end of the flexible assembly to the fixed end of the flexible assembly between the two symmetrical longitudinal flexures,
an interrupter repositioning slot is disposed at the fixed end side of the slot, and
a single strain gauge sensor is placed on the flexible assembly on either a right symmetrical longitudinal flexure or a left symmetrical longitudinal flexure of one of the symmetrical longitudinal flexures and neighboring the fixed end of the flexible assembly.

2. The friction force sensing system as set forth in claim 1 , wherein a photointerrupter sensor is attached on the fixed end of the flexible assembly.

3. The friction force sensing system as set forth in claim 2 , wherein an interrupter with a blocking extension in a structural relation with the flexible assembly is provided such that said blocking extension extends into a gap portion of said flexible assembly such that deflection of said interrupter within the photointerrupter sensor enables the measurement of friction forces.

4. The friction force sensing system as set forth in claim 3 , wherein the interrupter comprises a support means for fixedly accommodating said mounting element connecting said support means to the free end of said flexible assembly.

5. The friction force sensing system as set forth in claim 4 , wherein the support means of said interrupter comprises a mounting housing cut within said support means, allowing adjustment of the position of the blocking extension so as to extend into said photointerrupter sensor.

6. The friction force sensing system as set forth in claim 3 , wherein said interrupter is attached to said free end via a screw.

7. The friction force sensing system as set forth in claim 3 , wherein the force applied on the tip of said screw at a force application point deflects said free end of the flexible assembly and the latter to deflect the flexures thereof.

8. The friction force sensing system as set forth in claim 3 , wherein the interrupter is a monolithic body.

9. The friction force sensing system as set forth in claim 3 , wherein the flexible assembly is a monolithic body, and the interrupter is a monolithic body, and wherein the flexible assembly and interrupter are manufactured from a group including plastic, aluminum, steel and titanium alloys.

10. The friction force sensing system as set forth in claim 3 , wherein the two symmetrical longitudinal flexures are Gufficicntly long enough to accommodate the movement of said blocking extension.

11. The friction force sensing system as set forth in claim 3 , wherein movement of the blocking extension to and for under the applied force at the force application point interrupts the light transmission in said photointerrupter sensor.

12. The friction force sensing system as set forth in claim 3 , wherein the interrupter is a light blocker.

13. The friction force sensing system as set forth in claim 2 , wherein the photointerrupter sensor is an optocoupler sensor.

14. The friction force sensing system as set forth in claim 1 , wherein the flexible assembly is a monolithic body.

15. A friction force measuring method comprising the following steps:
a) fixedly attaching the friction force sensing system of claim 1 to a vertical surface,
b) rotating a horizontally extending rotary plate with a first test specimen placed on top of the same,
c) measuring friction force between said first test specimen and said rotary plate coated with the second specimen when said first test specimen pushes the force application point of the friction force sensing system by way of rotation of the rotary plate.

Assignees

• Univ Koc

Inventors

• Lazoglu Ismail
• Hussain Abbas
• Shams Sarmad

Classifications

• G01N19/02

  Measuring coefficient of friction between materials {(testing of tyres G01M17/02; determinations of friction coefficient used in vehicle braking or traction control systems B60T8/172)} · CPC title

• G01L1/2206

  Special supports with preselected places to mount the resistance strain gauges; Mounting of supports · CPC title

• G01L1/044 Primary

  of leaf springs · CPC title

• G01L1/04

  by measuring elastic deformation of gauges, e.g. of springs · CPC title

• G01L1/24 Primary

  by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis {using infrared, visible light, ultraviolet} · CPC title