## 3 Novel Rotating Motion Mechanism
### Intermittent Indexing Mechanism
#### 3.1.2 New Geneva Mechanisms  
The continuous circular motion designed by mechanical designers from the internet has been transformed into an intermittent circular motion mechanism [110]. The side of the driving wheel of this mechanism has a rounded triangular groove, and one of the connecting rods matches the groove, while the other is connected to the piston. The driven wheel is connected to the other end of the piston through two connecting rods. When the driving wheel rotates, it drives the piston to make a reciprocating linear motion, and then the driven wheel swings [110], as shown in Figure 49.  
A mechanical designer from the internet has designed the crank and groove wheel drive mechanism, consisting of a crank and groove wheel. The driving wheel of the mechanism is a protruding circular crank. When the crank rotates to the position where it meshes with the grooved wheel, it can drive the driven grooved wheel. However, since only the circular crank has a single protrusion, the grooved wheel can only rotate at a certain angle every time the crank spins. Therefore, the groove wheel undergoes intermittent circular motion when the circular crank rotates at a constant speed [110], as shown in Figure 50.  
The eccentric spiral intermittent mechanism designed by a mechanical designer from the internet [111] has an active wheel with a straight-end eccentric wheel, which rotates through a drive shaft. When the eccentric wheel rotates to the outside, it briefly contacts a step of the driven turntable, which drives it to rotate during the contact process. Then, when the eccentric wheel rotates to the inside, the turntable loses contact with it and stops rotating until the next contact. The mechanism can achieve intermittent rotational motion of the turntable [111], as shown in Figure 51.  
Figure 49: Schematic diagram of the mechanism transforming continuous circular motion into intermittent circular motion. Figure 50: Schematic diagram of crank and groove wheel drive mechanism. The above content shows that traditional indexing cams and Geneva mechanisms are still widely used in packaging machinery and machine tool changing systems due to their simple structure and reliable operation advantages. However, their shortcomings, such as vibration suppression, instantaneous impact, and insufficient load capacity under high dynamic working conditions, limit their application in high speed and high precision fields. In recent years, new mechanisms have gradually broken through traditional limitations through structural innovation and performance optimisation. Akin to the camshaft linkage indexing mechanism, the coaxial layout and indexing frequency of the input/output shaft have been significantly improved through the synergistic effect of the cam and parallelogram linkage. However, its complex structure leads to high assembly accuracy requirements and insufficient adaptability to dynamic loads. The eccentric spiral intermittent mechanism adopts a contact-type drive to simplify the spatial layout, but problems include contact surface wear and impact vibration. The current research trend focuses on the deep integration of intelligence and high performance materials, such as introducing active damping control algorithms to suppress dynamic impacts, developing wear-resistant coatings or self-lubricating materials to extend the life of key components, and balancing the compactness and dynamic performance of mechanisms through topology optimisation and multi physics field simulation technology. In the future, intermittent indexing transmission mechanisms will evolve towards high dynamic accuracy, low wear, and intelligence. Combining mechatronics design and modular manufacturing processes will promote them for high-end applications in precision automation equipment, micro-mechanical systems, and high speed indexing scenarios. At the same time, key challenges such as complex structural error accumulation, dynamic response delay, and cost-effectiveness balance must be addressed.