The preparation and processing of yarns and fabrics has evolved over time from spindle spinning and handloom weaving to the most modern and complex machines. Here we will limit ourselves to mentioning some of the most important applications of cams on textile and sewing machines. The weaving process consists of passing the weft thread over and under the warp threads. A brief introduction to weaving and looms is provided to clarify the role and importance of cams in these devices. Looms and heddle cams are illustrated first. The batten is often moved by a cam, which imposes a proper law of motion. A cam is also used in some shuttle launchers and projectile launchers to insert the weft. Knitting is another way of making fabric. The knitted fabric consists of a single thread that repeats in both directions the mesh that forms the elementary cell. More complex knitted fabrics are made with more threads. The fabric is made by needles that guide the yarn to create stitches. Knitting cams are used to control the various needle movements through the loops. Modern sewing machines began to appear in the mid-nineteenth century. Traditional sewing machines could only produce linear seams. The introduction of sewing machines equipped with cams made it possible to easily perform other processes. It should be noted that fulling mills are also used in the textile industry. A brief description of the old version of these can be found in Chap.3.

Authors and Affiliations

1. University of Bologna, Bologna, Italy

   Umberto Meneghetti

Appendix: Toggle Mechanism

It is interesting to describe the toggle mechanism shown in Fig. 10.14 in more detail because it illustrates the interaction between cams and linkages. These are mechanisms composed of elements connected by very simple kinematic pairs, such as rotoids (hinges) or prisms (straight guides).

Figure10.25 shows the diagram of the toggle and its connection to the torsion bar. For clarity, the proportions of the links and the amplitudes of the displacements have been changed from the real case in Fig. 10.14.

The cam, which is not shown in the figure, moves the rod G2 to the right until it slightly exceeds the alignment MN. Just before it is released, it returns a little from this situation (K is in line with MN). When the cam leaves the rod G2, the system G2-G1-A is free and returns very quickly to its initial position due to the pressure exerted by the torsion bar.

Left: Kinematic diagram of the toggle mechanism. Right: Illustration of the launch mechanism with two frames from an animation (https://youtu.be/valHdaWrOCA). In the first frame, the cam is moving the toggle, causing the torsion bar to rotate. In the right frame, the cam is no longer in contact with the toggle. This allows the bar to immediately release its elastic energy and the projectile is launched

Full size image

Reprints and permissions

© 2025 The Author(s), under exclusive license to Springer Nature Switzerland AG

Policies and ethics