Oldham-Coupling Second-Harmonic Balancer

This paper describes a mechanical balancer, based on the Oldham-type shaft coupling, for reducing or eliminating second-harmonic out-of-balance in mechanical systems. It is shown that by proper arrangement of two Oldham couplings, a balancer can be obtained for the elimination of second-harmonic shaking forces or second-harmonic shaking moments or a combination of both shaking forces and moments. The advantage of this balancer is that it runs at the primary speed of the machine to be balanced whereas the Lanchester-type balancer must run at two times the primary speed to achieve the same balancing effect. It is also shown that the addition of eccentric masses on the input and / or output shafts of the balancer couplings will permit first- and second-harmonic out-of-balance to be eliminated simultaneously. A prototype balancer has been tested to verify the concept.