Operators Manual
1. Use and wear limits:
Universal tool for testing the degree of wear of:
- Bolt couplings with coupling pin diameter 40 (DIN 74051)
- Bolt couplings with coupling pin diameter 50 (DIN 74052 und ECE R55)
- Towing eyes diameter of 40 mm DIN 11026 (ISO 5692-2) und DIN 74054 (ISO 8755)
- Towing eyes diameter of 50 mm DIN 74053 (ISO 1102) und ECE R55
- Tension eye height ring part 30 mm DIN 74054 (ISO 8755)
- Drawbar eye height ring part 45 mm DIN 74053 (ISO 1102)
Wear limits:
- towing eye

Figure 1
2. Inspection of different hitch devices:

Figure 2
2.1 Checking of coupling pins: (see Figure 3)
- Find out the nominal dimension of the coupling bolt offered by the type plate and the instruction guide of the trailer hitch.
- Slide the corresponding measuring range of the test gauge (marked with “coupling pin 40” or “coupling pin 50”) over the coupling pin. While doing this the coupling pin needs to be measured at its thinnest point. Normally this is the area, which touches the towing eye. It is important to measure the coupling pin in driving direction. Therefore the coupling pin needs to be demounted as the circumstances require.
- The test piece has reached the technical wear limit when it is completely immersed in the gauge (see Figure 3).

Figure 3
2.2 Check of towing eye 40 mm and 50 mm: (see Figure 4)
- Inner diameter of the eyelet is offered by the type plate and the instruction guide of the towing eye.
- Insert the gauge (marked „coupling ring 40“ or „coupling ring 50“) into the towing eye. The checkup must be conduct in at least four different positions at the extent.
- The towing eye has reached the wear limit when it is completely immersed in the gauge.

Fig. 4
2.3 Checking the drawbar eye height 40 mm and 50 mm: (see Fig. 5)
- Use the type plate and the installation and operating instructions for the drawbar eye to determine the nominal height of the ring section.
- Slide the corresponding measuring range of the test gauge (marked with “coupling ring 40 (nominal ring height 30.5 mm)” or “coupling ring 50 (nominal ring height 45 mm)”) onto the drawbar eye. The checkup must be conduct in at least four different positions at the extent.
- The towing eye has reached the wear limit when it is completely immersed in the gauge.

Fig. 5
3. Inspection/Maintenance of special tool:
For daily use, it is recommended that the individual test areas of the Walterscheid test gauge are checked once a year using the appropriate measuring equipment in accordance with the dimensions in Fig. 6. Depending on the actual number of uses, this period can be extended to 60 months. If the deviations are more than 0.1 mm, the test gauge must be replaced.

Fig. 6






