Scotch yoke engine

Abstract

The invention relates to a scotch yoke fluid device ( 10 ). The scotch yoke fluid device ( 10 ) has a crank ( 11 ) with a big end having an axis ( 14 ) which orbits around a main axis ( 15 ) for the crank ( 11 ). Connecting means ( 13 ) are mounted on the big end axis ( 14 ). There is at least one piston ( 22 ) mounted for reciprocating motion in a cylinder ( 18 ) along a piston axis. The piston has a cross-sectional area perpendicular to the piston axis. The piston also has guide means ( 16 ) which include a linear surface transverse to the piston axis. The guide means ( 16 ) engage engagement means on the connecting means. There is at least one restricting means ( 24 ) for constraining the piston ( 22 ) to move along the piston axis. The restricting means ( 24 ), or a constraining means ( 19 ) for the restricting means ( 24 ), or both, always extend into a volume defined by the swept area of the crank ( 11 ), projected along the main axis ( 15 ) of the crank ( 11 ). The invention also provides components, such as pistons, piston rods, restraining means and constraining means, made of composite fibre. The composite fibre may include both aligned and non-aligned material. The invention also relates to methods of manufacturing such components.

1 . A scotch yoke fluid device which includes: 
 a crank including a big end having an axis which orbits about a main axis for the crank;    connecting means mounted on the big end axis;    at least one piston mounted for reciprocal motion in a cylinder along a piston axis, the piston having a cross-sectional area perpendicular to the piston axis, the piston having guide means including a linear surface transverse to the piston axis, the guide means engaging engagement means on the connecting means; and    at least one restricting means for constraining the piston to move along the piston axis;    wherein the piston guide means bisects the piston cross-sectional area and at least part of each restricting means is located within a volume defined by the piston cross-sectional area projected along the piston axis, but is not located along the centre line of the bisection formed by the piston guide means,    characterised in that at least one of: 
 i) the or at least one of the restricting means; and  
 ii) a constraining means for the or at least one of the restricting means always extends into a volume defined by the swept area of the crank projected along the main axis of the crank.  
   
     
     
         2 . The fluid device of  claim 1 , wherein the constraining means includes a groove or channel into which the restraining means fits.  
     
     
         3 . The fluid device of  claim 2 , wherein the constraining means is formed in or bolted to a crank case.  
     
     
         4 . The fluid device of  claim 1 , wherein the restraining means and/or the constraining means meets the circumference of the swept volume of the crank.  
     
     
         5 . The fluid device of  claim 1 , wherein the restraining means and/or the constraining means crosses the circumference of the swept volume of the crank.  
     
     
         6 . The fluid device of  claim 1 , wherein the constraining means is relocatable.  
     
     
         7 . The fluid device of  claim 1 , wherein the constraining means includes or comprises one or more rollers.  
     
     
         8 . The fluid device of  claim 1 , having more than one piston.  
     
     
         9 . The fluid device of  claim 1 , wherein the or at least one piston is combined with the connecting means.  
     
     
         10 . The fluid device of  claim 9 , wherein the combined piston and connecting means is composed of a fibre composite.  
     
     
         11 . The fluid device of  claim 10 , wherein the fibre composite includes non-aligned material and/or chopped strand tape.  
     
     
         12 . The fluid device of  claim 10 , wherein the fibre composite is a carbon-carbon composite or a composite using fibres chosen from the group: kevlar carbon, copper strands, glass, plastic or a combination of two or more of the foregoing.  
     
     
         13 . The fluid device of  claim 12 , wherein the non-aligned material and/or chopped strand tape is mixed with aligned material into a resin.  
     
     
         14 . The fluid device of of  claim 10 , wherein the fibre composite also includes metal.  
     
     
         15 . The fluid device of  claim 14 , wherein the metal is aluminium.  
     
     
         16 . A scotch yoke fluid device which includes: 
 a crank including a big end having an axis which orbits about a main axis for the crank;    connecting means mounted on the big end axis;    at least one piston mounted for reciprocal motion in a cylinder along a piston axis, the piston having a cross-sectional area perpendicular to the piston axis, the piston having guide means including a linear surface transverse to the piston axis, the guide means engaging engagement means on the connecting means; and    at least one restricting means for constraining the piston to move along the piston axis;    wherein the piston guide means bisects the piston cross-sectional area and at least part of each restricting means is located within a volume defined by the piston cross-sectional area projected along the piston axis, but is not located along the centre line of the bisection formed by the piston guide means,    characterised in that the or at least one piston is combined with the connecting means.    
     
     
         17 . The fluid device of  claim 16 , wherein the combined piston and connecting means is composed of a fibre composite.  
     
     
         18 . The fluid device of  claim 17 , wherein the fibre composite includes non-aligned material and/or chopped strand tape.  
     
     
         19 . The fluid device of  claim 17 , wherein the fibre composite is a carbon-carbon composite or a composite using fibres chosen from the group: kevlar carbon, copper strands, glass, plastic or a combination of two or more of the foregoing.  
     
     
         20 . The fluid device of  claim 19 , wherein the non-aligned material and/or chopped strand tape is mixed with aligned material into a resin.  
     
     
         21 . The fluid device of of  claim 17 , when the fibre composition also includes metal.  
     
     
         22 . The fluid device of  claim 21 , wherein the metal is aluminium.  
     
     
         23 . A component suitable for a scotch yoke fluid device including the device of  claim 1  or  16 , the component being composed of a fibre composite.  
     
     
         24 . The component as claimed in  claim 23 , wherein the fibre composite includes non-aligned material and/or chopped strand tape.  
     
     
         25 . The component of  claim 23 , wherein the fibre composite is a carbon-carbon composite or a composite using fibres chosen from the group: kevlar carbon, copper strands, glass, plastic or a combination of two or more of the foregoing.  
     
     
         26 . The component of  claim 25 , wherein the non-aligned material and/or chopped strand tape is mixed with aligned material into a resin.  
     
     
         27 . The composite of of  claim 23 , wherein the fibre component also includes metal.  
     
     
         28 . The component of  claim 27 , wherein the metal is aluminium.  
     
     
         29 . (Cancelled)  
     
     
         30 . (Cancelled)  
     
     
         31 . (Cancelled)