Customized Non-Rotating Cylinder for Discharge Valves

Previously, we designed a compact anti-rotation cylinder featuring a yoke plate and guide rod structure. However, for larger cylinders, this type of non-rotation structure may not be suitable. 

Coincidentally, a customer had previously ordered a batch of larger non-rotation cylinders from us. These cylinders featured a different non-rotation mechanism compared to the compact model. This article will introduce another type of non-rotation cylinder that we manufacture, using this case as an example.

Customer Requirements

A customer approached us with an outline diagram, requesting a cylinder for air discharged valves. The required cylinder specifications included:

◆ Bore size: φ100mm

◆ Stroke: 420mm

◆ Non-rotation function for the piston rod

◆ The dimensions match the customer's existing system 

Due to installation constraints, the front cover had to be circular. Circular end caps cannot be locked using tie rods and nuts. Therefore, a groove was designed at the front of the end cap, allowing it to be conveniently mounted onto the bracket. Instead of passing through the front end cap, the tie rods and nuts directly secure the bracket, which in turn clamps the end cap tightly against the cylinder tube.

The piston was designed as a split-type structure. The front half of the piston was threaded onto the piston rod, while the rear half was secured using a groove on the piston rod, effectively locking both parts together.

How Does the Non-Rotation Mechanism Work?

Due to space constraints, the non-rotation function had to be achieved through the internal structure rather than external guide elements.

Our design team developed an innovative structure, modifying the piston rod into a hollow structure. Slightly larger holes were machined at both ends of the rod, with threads cut inside these holes. These threads allowed the brass sleeve to be securely screwed into the piston rod.

Unlike common sleeves, this brass sleeve featured external threads that matched the internal threads of the piston rod, ensuring a secure connection. The internal part of the sleeve had a 12mm square hole, which was the key to achieving the Non-rotation function.

The back cover was also redesigned. It did not include a air cushioning structure, making it thinner than a standard end cap. The air inlet was positioned at the bottom of the cap, and there was a central mounting hole designed to accommodate a square rod.

The square rod played a crucial role in the non-rotation mechanism. It was mounted onto the base and passed through both the brass sleeve and hollow piston rod. As the cylinder operated, the piston and piston rod moved the brass sleeve forward, while the square rod prevented the sleeve from rotating, thereby restricting the rotation of the piston rod.

Additionally, the front end of the piston rod could not be completely hollow, as per the customer’s request. Therefore, after finalizing the non-rotation mechanism, we inserted a plug into the front of the piston rod, allowing the customer to mount a bracket and joint that matched their existing system.

Sample Testing

Once the design was finalized, we produced six sample units and conducted rigorous tests, including:

◆ Dimensional verification

◆ Stroke accuracy testing

◆ Air tightness inspection

◆ Simulated operational testing

After confirming that everything met the required standards, the samples were delivered to the customer for testing. Following a period of use, the customer reported that the cylinders performed flawlessly. Satisfied with the results, they placed a follow-up order, leading to further product collaboration and a deeper partnership with us.

About Fokca (Fescolo)

Fokca (Fescolo) has been deeply involved in the pneumatics industry for many years, specializing in custom pneumatic components. Our technical team thoroughly understands customer requirements and applies its extensive industry expertise to develop innovative solutions tailored to our clients’ needs.

You can explore more of our case studies, and if you have any inquiries, please contact us.