dial indicator torque wrenches

dial indicator torque wrenches is also called the torque wrench, torque is the product of the force and distance, when the thread fasteners such as fastening screw bolt and nut torque size needs to be controlled, to ensure that the thread fastening and not because of destruction of the torque is too large, so use the Mechanical Torque Wrenches to operate. First set a maximum torque, torque reaches the set value when, wrench "card tower" noise or wrench joint bending Angle, this is already tightening torque. Torque wrench can be divided into: preset torque wrench, 

Construction of calibration of torque wrenches

Camshaft is a cylindrical rod of the same length with the cylinder group.Above there are several cam, used to drive the valve.Camshaft bearing at one end, and at the other end is connected to the drive wheels.
Side of the cam is egg-shaped.calibration of torque wrenches design goal is to ensure that the cylinder sufficient intake and exhaust, specifically, in the shortest possible time in the valve opening and closing action.Taking into account the durability and smooth operation of the engine, valve or the deceleration during opening and closing movements too much impact, otherwise dial indicating torque wrenches will cause severe valve wear, noise, or other serious consequences.
Generally inline engine, one cam per valve, v engine or a horizontally opposed engine is one cam per two valves share.Rotary engine and valve valve engines due to their special construction, does not need the cam.

Torque wrench calibration, week

1. Hexagon reducer bushes in accordance with JJG707-90 of the torque wrench calibration procedures.Refer to torque wrench torque wrench accuracy test results with a torque wrench setting of deviation.Repeatability means the same torque wrench on the same conditions, hydraulic torque wrench chart detected the same torque value, the consistency of the test results.Prevailing torque wrench accuracy of 4%, torque wrench is detected, more than 4% the scope of errors depending on the torque wrench.Torque Wrenches out there are two main reasons: ⑴ torque wrench mutations (jam or poor repeatability).Because of the torque wrench and high frequency of use for a long time, internal parts subject to wear, deformation, resulting in torque mutations.

⑵ excursion of the torque wrench.Passed due to torque wrench measures rely on springs, in frequent use, can produce some drift.(Drift refers to the actual testing of torque wrench error with the torque wrench setting value)
2. refers to the day in the week just before using a torque wrench to the torque wrench settings for testing and understanding of the torque wrench.Due to the torque wrench after frequent use and are prone to drift, it should verify that the torque wrench before starting the work week, check the status of a torque wrench and adjust the drift, ensure the accuracy of the torque wrench.

Torque wrench use

When the torque is applied, hand preset torque screwdrivers the tick mark locations in the middle of the handle.Square head and sleeve, nut/bolt secure connections (for opening/plum series Low Profile Torque Wrench, open/ring ends should be fully inserted into the sink/nut), the force only in the direction of the torque wrench marked,

Torque wrench setting adjusted to roughly 2 forms:

One, belonging to the adjustable screw driven loading calibrators adjustment method.Loosen the rear lock clamps according to the needed value benefits at the end of indexing wheel (clockwise increases the torque, counterclockwise to reduce torque) the index wheel scale consistent with the torque wrench setting torque wrench calibration device calibration.
Second, belongs to the set-value hydraulic torque wrench testers adjustment.Release the rear cover the corresponding Allen key loosen the locking screw adjusting tool to rotate the push ring setting torque values torque Tester calibration torque fixed locking screw locked back cover

Torque wrench with torque process and structure

With torque wrench calibrator imposed torque Shi, through and torque wrench of ratchet head solid connection of sleeve connection need imposed torque of nut/bolt, hand master in portable torque wrench calibrators handles Shang of effective scale line, Shun clockwise or inverse clockwise Afterburner, this force led nut/bolt, dang nut/bolt tight solid, and by with of torque and torque wrench set of torque equal Shi, torque wrench of ratchet led torque wrench of head, put torque passed to triggers, triggers to right sliding (unloading force).When the roller getting tube, will issue a "clicked" signal, stop immediately after you hear the signal strength, remove the torque wrench to complete torque.

Torque wrench calibration procedures

1. calibration of torque wrenches preparations
1.1 before the first use of the torque meter is fixed on the wall or on a level platform;
1.2 the torque meter power cable connected to the 220V power supply, turn the power switch on, Preheat for 20 minutes;2. periodical calibration
2.1 types of hydraulic torque wrench manufacturers time is 6 months;2.2 dial torque wrench
2.2.1 under be liable to join square drive wrench, choosing the right connection head insert the sensor hole, normal, peak torque meter switch to normal, torque meter track display function, rotate the zero potentiometer to zero point, fitted tested wrenches (should be zero before zero adjustment wrench insert).Note: after you insert the wrench, torque meter displays a certain value before without Afterburner, this value is generated by the wrench weight, can no longer be eliminated;

2.2.2 holding the handle of the wrench parts along the vertical direction flipping the wrench, uniform testing three points observation point by point the torque of the torque meter shows values and repeat 3 times.According to the following formula to calculate the present value relative errors (Q) and the relative variation in the indicating value (b), and fill in the result in the torque wrench calibration log sheet: q = (m – m) x100%
B=(Mmax―Mmin)×100%
In the formula: M-----testing torque value m---three times displays arithmetic mean Mmax----torque maximum torque Mmin----test display test three times three times display the minimum torque 2.2.3 calibration determination
2.2.3.1 the absolute value in Q and the b value ≤ 10% ≤ 10%, the torque to normal use;
2.2.3.2 Q the absolute >10% or b >10% should repair the torque wrench adjustment under the circumstances;Still not up to the required torque wrench adjusted scrap should be given;