Test device for determining the friction and prestress values of screwed connections

• US 6,810,747 B2
• Filed: 09/18/2002
• Issued: 11/02/2004
• Est. Priority Date: 02/07/2000
• Status: Expired due to Fees

• Current Assignee: Kistler Holding AG
• Original Assignee: Kistler Holding AG
• Inventors: Engler, Paul, Haab, Rudolf Hans
• Primary Examiner(s): Noori, Max H.
• Application Number:
  US10/203,100
• Publication Number:
  US 20030145657A1
• Time in Patent Office: 776 Days
• Field of Search: 737/61
• US Class Current: 73/761
• CPC Class Codes: G01L 5/24 for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed

Abstract

A testing for screw connections, comprising a sensor carrier plate with sensors on both sides and being mounted on a base plate, whereby the sensors are sandwiched between a torque introduction plate and a torque sustaining plate, the sensors detecting separately both head and thread friction forces and a preload force.

Claims

1. A testing device for screw connections, comprising a sensor carrier plate with sensors on both sides and being mounted on a base plate, whereby the sensors and sensor carrier are sandwiched between a torque introduction plate and a torque sustaining plate, the sensors detecting separately both head and thread friction forces and a preload force.

2. The testing device for screw connections according to claim 1, wherein the plates are joined with adapters allowing screws of different dimensions to be measured with the same device for tightening and loosening torques and also forces.

3. The testing device for screw connections according to claim 1, wherein the sensors are arranged in one or more of a triangle, a rectangle, a square and a circle for symmetrical force distribution, the sensors being disposed in pairs on both sides of the carrier plate.

4. The testing device for screw connections according to claim 1, wherein the sensors are piezoelectric sensors and whereby the sensors measure pressure and shear simultaneously.

5. The testing device for screw connections according to claim 4, wherein crystal elements of the piezoelectric sensors are integrated directly in the carrier plate.

6. The testing device for screw connections according to claim 1, wherein electronic amplifiers are integrated directly in the carrier plate.

7. The testing device for screw connections according to claim 6, wherein the electronic amplifiers having range switchover enabling especially interesting parts of measurements to be magnified by factors.

8. The testing device for screw connections according to claim 1, wherein the sensors are other than piezoelectric sensors.