Punk® couplings use a radical reinterpretation of the well-established Cardan joint mechanism to transmit power between misaligned shafts.
This novel approach – which we call our geometric philosophy – achieves Cardan motion in a unique way, creating an extremely compact and robust torque coupling. At the heart of this approach is the ‘Mohican’, the defining feature of the first Punk® coupling and the inspiration for all that came after.
Exploded view of a Punk® Prime 5° Sealed Coupling
THE PUNK® PRIME
The Punk® Prime is composed of three nested rings with spherical mating surfaces: effectively it’s a spherical bearing inside a spherical bearing. Each male surface has a pair of diametrically opposed cylindrical keys, which we call ‘Mohicans’ as they resemble the famous punk hairstyle. The Mohicans are received into Mohican slots, such that each mating pair of rings has a single free axis of relative rotation, one at 90° to the other. Thus, the mid ring acts like the cruciform component in a Cardan joint, rocking back and forth to cater for angular misalignment.
The Punk® Prime elegantly separates the shaft torque from axial and radial loads and carries these load components across the joint via different paths. The load capacity across each of these paths is extremely high, making the Punk®Prime one of the most torque-dense products on the market.Learn More
The PUNK® GIM-BALL
As with the Punk® Prime, the Punk® Gim-Ball is composed of three nested rings with spherical mating surfaces. In this case, the Mohicans are replaced with axles to produce an equivalent pair of rotation axes. Thus, the mid ring continues to act like the cruciform component in a Cardan joint, rocking back and forth to cater for angular misalignment.
As with the Punk® Prime, the Punk® Gim-Ball elegantly separates the shaft torque from axial and radial load and carries these load components across the joint via different paths.Learn More
The PUNK® Failsafe
The Punk® Failsafe combines the Punk® Prime and Punk® Gim-Ball to produce a coupling with multiple redundancies in the torque transmission path. These couplings will remain operational in the presence of multiple element failures, making them ideal for high integrity machine trains where reliability is key.
The torque carrying elements of the Punk® Prime and Gim-Ball (the Mohicans and axles) cooperate to produce Cardan motion on the mid-ring. In the event of both axles failing, the torque will continue to be carried by the Mohicans and vice-versa. A waiting failsafe torque path is achieved by putting a small clearance between the Mohican or axle contact surfaces, thus the ‘waiting’ elements are not loaded unless complete failure of the primary torque path occurs.Learn More
All Punk® couplings can be concentrically supported in a bearing to produce a multifunctional support bearing and torque coupling combination. This unique product allows shaft support bearings to be eliminated, reducing parts count and system weight. It also greatly simplifies shaft alignment, and reduces the impact of coupling imbalance.
PUNK® COUPLING LUBRICATION AND CONTAMINATION SEAL
The geometry of a Punk® coupling allows for a robust seal; keeping lubrication in and contamination out. In addition, the Punk® coupling geometric motion ensures ‘wet’ lubrication is constantly pumped around the coupling, resulting in the potential for a ‘sealed for life’ coupling.
Sealing can also be used in conjunction with dry self-lubricated liners, thus ensuring no ingress of potentially damaging contaminates.
Our seal allows for up to 10 degrees of angular misalignment, when used in a double flex-flex Punk® coupling arrangement.
PUNK®COUPLING SIZER AND ANALYTICS SOFTWARE
Developed from ‘first principals’, our Punk® Coupling Sizer and Analytics Software is capable of automatically sizing and analysing a Punk® coupling for any given application. Our sizing software outputs component dimensions for a specified shaft size and maximum misalignment angle. User defined options on interface type (key or spline), materials and sealing methods are automatically incorporated into the design.
Our analytics software predicts the sized coupling performance in terms of torque, speed and misalignment envelopes. These are presented as charts of torque versus speed versus misalignment, maximum power versus misalignment and maximum speed versus misalignment. Our sizing and performance routines can also be combined to automatically produce a catalogue of key dimensions, outline drawings and performance envelopes for a series of pre-defined shaft sizes.
Ongoing development: We have recently engaged Cardiff University, School of Engineering, to carry out a comprehensive strength and tribology test programme. The results from which will be incorporated in both our Punk® Coupling Sizer and Analytics Software, and ongoing product development work.