Load cells
A force measuring bolt is a connecting bolt between force-transmitting machine elements which, in addition to its function as a bolt, enables the transverse forces occurring in it to be measured at the same time . This measurement is carried out using strain gauges or magnetic coils , for example .
Force pins are also known under the following terms:
- Load measuring pins
- Force measuring axis
- Loadpin (in English-speaking countries)
- Axes dynamométriques (in French-speaking countries)
The measuring bolts are used in particular in hydraulics on lifting equipment such as cranes , lifts and cable cars .
In the three-point hydraulics on tractors , too , the electronic hitch control is controlled by force measuring pins. The control circuit between hydraulic cylinder - force measuring bolt - hydraulic valve / pump is monitored and the deflection of the hydraulic cylinder is determined via the bolt attached to the hydraulic cylinder in the direction of the force .
Mounting options
Load pins must be attached so that their orientation is fixed. The axial displacement and the rotation must be fixed. Proper restraint is essential to get accurate results. An axle holder according to DIN15058 is used for this.
The axle holder grooves are usually designed in accordance with DIN15058. Up to a diameter of 100 mm, this standard recommends using an axle holder and, in addition, two axle holders for each load cell . A small gap between the axle holder and the axle holder groove is necessary to get the best results. The gap should be around 0.2 mm so that the force measuring pin in the counter bearing can bend freely.
This installation variant is referred to as a bolt retainer with axle holder groove and axle holder plate. Other variants are the following:
- Bolt lock with one-sided head, castle nut and split pin
- Bolt lock with head plate welded on one side and anti-twist lock