Drive coupling

Abstract

A drive coupling 10 has an outer plate 12 and an inner plate 14 . Inner plate 14 is positioned within the inner periphery 16 of outer plate 12 . The inner plate 14 includes a plurality of outwardly extending projections 18 . The inner periphery 22 of outer plate 12 includes a plurality of recesses 24. The drive coupling 10 further comprises a plurality of compression springs 28 arranged between respective projections 18 of inner plate 14 and the respective side wall of the recess 24 of outer plate 12 . A first retaining plate 42 is positioned by passing it over shaft 32 . A spacer ring 48 is positioned such that it abuts one side of the inner plate 14 . A second retaining plate 50 is located on the other of the inner and outer plates. Bolts 56 are used to hold the retaining plates 42 and 50 together. The drive coupling 10 is designed to carry the entire rated torque requirement of the unit on the compression springs, thus providing a continual cushioning action to the drive line whilst allowing a maximum angular movement if an obstruction is encountered.

1 . A drive coupling comprising 
 an inner plate having one or more outwardly extending projections,    an outer plate having one or more inner peripheral recesses, each of the one or more inner peripheral recesses having two inwardly extending wall portions,    and one or more coil springs    each of the one or more outwardly extending projections of the inner plate being positioned within an associated inner peripheral recess of the outer plate, with a coil spring being located between one face of each of the one or more outwardly extending projections of the inner plate and one of the inwardly extending wall portions of the associated inner peripheral recesses of the outer plate, there being an absence of any coil spring between another face of each of the projections on the inner plate and the other inwardly extending wall portion of the associated inner peripheral recess on the outer plate,    wherein rotation of one of the inner plate and the outer plate causes a reaction force in the at least one coil spring, said reaction force being transmitted to the other of the inner plate and the outer plate to thereby cause rotation of the other plate.    
   
   
       2 . A drive coupling as claimed in  claim 1  wherein the inner plate has a plurality of outwardly extending projections and the outer plate has a plurality of inner peripheral recesses, the projections of the inner plate extending into respective recesses of the outer plate, and the one or more coil springs comprise a plurality of coil springs, each positioned between a respective projection of the inner plate and a wall of the corresponding recess of the outer plate.  
   
   
       3 . A drive coupling as claimed in  claim 2  wherein the projections of the inner plate extend in a generally radial direction and the recesses in the inner periphery of the outer plate are defined by the inwardly extending wall portions of the inner peripheral wall of the outer plate.  
   
   
       4 . A drive coupling as claimed in any one of the preceding claims wherein the inner plate and the outer plate are in substantial alignment in a longitudinal direction.  
   
   
       5 . A drive coupling as claimed in any one of the preceding claims wherein the one or more coil springs are positioned in a generally circumferential direction.  
   
   
       6 . A drive coupling as claimed in any one of the preceding claims further comprising a first retaining plate positioned on one side of the inner and outer plates, a second retaining plate positioned on the other side of the inner and outer plates and connecting means to connect the retaining plates together to thereby maintain the inner and outer plates therebetween.  
   
   
       7 . A drive coupling as claimed in  claim 6  wherein the retaining plates are connected to the outer plate.  
   
   
       8 . A drive coupling as claimed in  claim 7  wherein the connecting means for connecting the retaining plates comprise bolts and the outer plate is provided with apertures for receiving the bolts.  
   
   
       9 . A drive coupling as claimed in any one of the preceding claims wherein the one or more coil springs comprise one or more compression springs.  
   
   
       10 . A drive coupling as claimed in  claim 9  further comprising positioning means on one of the inner plate or outer plate to position the one or more compression springs.  
   
   
       11 . A drive coupling as claimed in  claim 10  wherein the positioning means comprises spring guide projections extending from one wall of each inner peripheral recess of the outer plate.  
   
   
       12 . A drive coupling as claimed in  claim 11  wherein the spring guide projections are sized such that the compression springs fit over the projections.  
   
   
       13 . A drive coupling as claimed in any one of the preceding claims further comprising a shaft connected to or formed with one of the inner or outer plates.  
   
   
       14 . A drive coupling as claimed in  claim 13  wherein the inner plate has a first shaft formed therewith or attached thereto.  
   
   
       15 . A drive coupling as claimed in  claim 13  or  claim 14  wherein the outer plate has a shaft formed therewith or connected thereto.  
   
   
       16 . A drive coupling as claimed in  claim 6  wherein one of the retaining plates has a shaft connecting means for connecting a shaft thereto, or has a shaft attached thereto.  
   
   
       17 . A drive coupling as claimed in any one of the preceding claims wherein during normal use of the drive coupling, the at least one coil spring maintains separation between the inner plate and the outer plate in a circumferential direction.  
   
   
       18 . A drive coupling comprising 
 an inner plate having one or more outwardly extending projections,    an outer plate having one or more inner peripheral recesses, with at least one inner peripheral recesses having two inwardly extending wall portions,    and one or more coil springs,    at least one of the outwardly extending projections of the inner plate being positioned within an associated inner peripheral recess of the outer plate, with a coil spring being located between one face of the outwardly extending projections of the inner plate and one of the inwardly extending wall portions of the associated inner peripheral recesses of the outer plate,    wherein the one or more coil springs bias the inner plate to a first position relative to the outer plate when no drive force is applied to the drive coupling and wherein the inner plate can move in only one direction from the first position relative to the outer plate, and    wherein rotation of one of the inner plate and the outer plate causes a reaction force in the at least one coil spring, said reaction force being transmitted to the other of the inner plate and the outer plate to thereby cause rotation of the other plate.    
   
   
       19 . A drive coupling substantially as hereinbefore described with reference to the accompanying drawings.