How to determine the dimensions of a transmission belt?

How to measure the size of the belt？

Tools required: rope, flat steel ruler, or flexible measuring tape, caliper

How to measure the dimensions of a rubber timing belt?

1. The surest method is to count the teeth. (count the teeth on the old belt) or measure the length. The length requires the precise pitch line length. You can cut the old belt, straighten it, and measure, or measure the circumference of the belt on the machine. Alternatively, calculate the belt length as half the circumference of each terminal pulley plus the distance between the two center distances.

2. Measure the timing belt pitch (the distance between tooth centers is the pitch; measure the pitch of 11 teeth and divide by 10 to obtain the precise pitch).

3. Measure the belt width.

4. Measure the belt thickness.

For coated timing belts, please note that thickness is categorized into coating thickness and total thickness. We have compiled this information into images and videos for your reference.

Usually, coated timing belts are used in vertical form-fill-seal machines with hole，hole patterns, such as round holes, square holes, plum holes, oval holes, water drop holes, countersunk holes，etc.

We need to drill holes in the drawings. If there are no drawings, then we need to measure the size of the holes.please check！

It is worth noting that the center distance of rubber timing belts is relatively difficult to determine accurately. In contrast, the center distance of PU timing belts can be measured directly using calipers, as shown in Figure 5.

How to Measure the Dimensions of a flat belt？

Measuring the dimensions of a flat belt is relatively straightforward—simply measure its circumference, width, and thickness. However, note that flat belts come in various materials such as nylon, PVC, PU, and rubber. If the belt thickness exceeds 5mm or the machine has limited adjustment range, distinguish between the inner and outer circumferences, as they differ. For example, 8mm-thickness rubber flat belt on a box-making machine, the inner circumference is 1000mm and the outer circumference is 1050mm, with a 50mm difference between them. This is calculated using the formula: Outer circumference ≈ Inner circumference + (π × Thickness × 2).

We have recorded a video showing how to measure the rubber flat belts for folding machine. Please have a look.

How to Measure the Dimensions of PVC conveyor belts？

The measurement method for PVC conveyor belts is the same as for flat belts. It is worth noting that PVC belts have different jointing methods—open-ended and endless loop—and their circumferences vary slightly. However, most machines have some adjustment range, so measuring the length, width, and thickness is sufficient.

How to Measure the Dimensions of a V-Belt？ 

There are numerous V-belt models, including A, B, C, D, E, SPB, XPB, 5VX, 8VX, and so on. These designations are typically marked on the belt itself. If these markings are worn off, we can determine the correct model by measuring the belt width. Alternatively, you can inform our sales personnel of the application field or the specific machinery it will be used in, and we will provide you with the precise model match. Once the correct model is identified, the belt length can be determined. V-belts have parameters such as Li, La, Lp, and Le, which represent:

La denotes the outer circumference;

Li denotes inner circumference;

Lp indicates pitch line length;

Le represents effective pitch line length.

V-belts, you only need to determine the model and circumference.and figure out what the circumference is Li, La, Lp, and Le.

FAQ

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