Apparatus for use as a gas compressor or blower

Abstract

A gas compressor or blower comprising a cylinder having air intake and exhaust ports; a piston which is rotatably and reciprocably movable in the cylinder; valve means for admitting air into and exhausting air from at least one chamber lying to one side of the piston; a piston shaft to which the piston is secured, the piston shaft passing through seals at the axial ends of the cylinder; means for applying a rotary drive to the piston rod; and a cam arrangement for causing reciprocation of the piston rod as this rotates; the arrangement of ports and valve means being such that as the piston rotates and reciprocates air is induced into the chamber, is compressed in the chamber and then exhausted from the chamber.

What I claim is: 
     
       1. A gas compressor or blower comprising a cylinder having air intake and exhaust ports; a piston which is rotatably and reciprocably movable in the cylinder; valve means for admitting air into and exhausting air from at least one chamber lying to one side of the piston; a piston shaft to which the piston is secured, the piston shaft passing through seals at the axial ends of the cylinder; means for applying a rotary drive to the piston .[.rod.]. .Iadd.shaft.Iaddend.; and a cam arrangement for causing reciprocation of the piston .[.rod.]. .Iadd.shaft .Iaddend.as it rotates; the arrangement of ports and valve means being such that as the piston rotates and reciprocates air is induced into the chamber, is compressed in the chamber and then exhausted from the chamber; means for axially balancing the piston shaft comprising support means, and means for mounting said cylinder on said support means so that said cylinder has free axial movement on said support means. 
     
     
       2. A gas compressor or blower comprising a cylinder having air intake and exhaust ports; a piston which is rotatably and reciprocably movable in the cylinder; valve means for admitting air into and exhausting air from at least one chamber lying to one side of the piston; a piston shaft to which the piston is secured, the piston shaft passing through seals at the axial ends of the cylinder; means for applying a rotary drive to the piston .[.rod.]. .Iadd.shaft.Iaddend.; and a cam arrangement for causing reciprocation of the piston .[.rod.]. .Iadd.shaft .Iaddend.as it rotates; the arrangement of ports and valve means being such that as the piston rotates and reciprocates air is induced into the chamber, is compressed in the chamber and then exhausted from the chamber; said cam arrangement comprising a first cam at a first end of the cylinder for driving the piston shaft in a first axial direction and a second cam at a second end of the cylinder for driving the piston shaft in a second axial direction, each cam being a face cam secured to rotate with the piston shaft and bearing on roller means carried at the respective end of the cylinder, each said roller means comprising two roller assemblies bearing on a common face cam, the roller assemblies being opposed by 180° and spaced equidistantly from the center line of the piston shaft, and both roller assemblies mounted on a carrier which is mounted on the cylinder for pivotal movement about an axis perpendicular to the axis of the piston shaft. 
     
     
       3. A gas compressor or blower comprising a cylinder having air intake and exhaust ports; a piston which is rotatably and reciprocably movable in the cylinder; valve means for admitting air into and exhausting air from at least one chamber lying to one side of the piston; a piston shaft to which the piston is secured, the piston shaft passing through seals at the axial ends of the cylinder; means for applying a rotary drive to the piston .[.rod.]. .Iadd.shaft.Iaddend.; and a cam arrangement for causing reciprocation of the piston .[.rod.]. .Iadd.shaft .Iaddend.as it rotates; the arrangement of ports and valve means being such that as the piston rotates and reciprocates air is induced into the chamber, is compressed in the chamber and then exhausted from the chamber; the means for applying rotary drive to the piston shaft comprising projections extending axially from and spaced radially from an end member secured to the piston shaft, a drive shaft, and means rotatable with the drive shaft and bearing on the projections to drive the piston shaft in the same sense as the drive shaft while allowing axial movement of the piston shaft relative to the drive shaft; said projections spaced equidistantly to each side of the piston shaft and the means rotatable with the drive shaft applies equal force to each of the projections and comprises a bell crank lever, a first lever having a first end and a second end and pivoted to a first arm of the bell crank lever and bearing at said first end on a first one of said projections, a second lever having a first end and a second end and pivoted to a second arm of the bell crank lever and bearing at a first end on a second one of said projections, said first and second levers bearing against each other at said second ends, the moment arm from the pivot point of each lever to its point of contact with the respective projection being equal to the moment arm from said pivot point to the point of contact with the other lever. .Iadd. 4. A gas compressor or blower comprising a cylinder having gas intake and exhaust ports; a piston which is rotatably and reciprocably movable in the cylinder; valve means for admitting gas into and exhausting gas from at least one chamber lying to one side of the piston; a piston shaft to which the piston is secured, the piston shaft passing through seals at the axial ends of the cylinder; means for applying a rotary drive to the piston shaft; and a cam arrangement for causing reciprocation of the piston shaft as it rotates; the arrangement of ports and valve means being such that as the piston rotates and reciprocates, gas is induced through the intake ports into the chamber, is compressed in the chamber and then exhausted from the chamber through the exhaust ports, said cam arrangement comprising a first cam for driving the piston shaft in a first axial direction and a second cam for driving the piston shaft in a second axial direction, each cam being a face cam secured to rotate with the piston shaft and bearing on roller means comprising two roller assemblies opposed by 180° and spaced equidistantly from the center line of the piston shaft, and a carrier on which both roller assemblies are mounted and which is mounted on the cylinder for pivotal movement about an axis perpendicular to the axis of the piston shaft. .Iaddend..Iadd. 5. A gas compressor or blower comprising a cylinder having gas intake and exhaust ports; a piston which is rotatably and reciprocably movable in the cylinder; valve means for admitting gas into and exhausting gas from at least one chamber lying to one side of the piston; a piston shaft to which the piston is secured; the piston shaft passing through seals at the axial ends of the cylinder; means for applying a rotary drive to the piston shaft; and a cam arrangement for causing reciprocation of the piston shaft as it rotates; the arrangement of ports and valve means being such that as the piston rotates and reciprocates, gas is induced through the intake ports into the chamber, is compressed in the chamber and then exhausted from the chamber through the exhaust ports; the means for applying rotary drive to the piston shaft comprising a first projection having a first bearing surface, a second projection having a second bearing surface, the two projections being fixed to rotate with the piston shaft and said bearing surfaces being spaced equidistantly to each side of the piston shaft and facing in the same sense of rotation; a drive shaft and means rotatable with the drive shaft and bearing on the respective bearing surfaces to drive the piston shaft in the same sense as the drive shaft while allowing axial movement of the piston shaft relative to the drive shaft; said means rotatable with the drive shaft comprising a bell crank lever secured to the drive shaft, a first lever pivoted to a first arm of the bell crank lever and bearing at a first end on the first bearing surface, a second lever pivoted to a second arm of the bell crank lever and bearing at a first end on the second bearing surface, said first and second levers bearing against each other at their second ends, the moment arm from the pivot point of each lever to its point of contact with the respective projection being equal to the moment arm from said pivot to the joint of contact with the other lever. .Iaddend. .Iadd. 6. A gas compressor or blower according to claim 5 in which the means rotatable with the drive shaft further comprises a second bell crank lever journalled on the drive shaft, a third lever pivoted to a first arm of the second bell crank lever and bearing at a first end on a third bearing surface on a projection fixed to rotate with the piston shaft, a fourth lever pivoted to a second arm of the second bell crank lever and bearing at a first end on a fourth bearing surface on a projection fixed to rotate with the piston shaft, the third and fourth bearing surfaces facing in the opposite sense of rotation to the first and second bearing surfaces, said third and fourth levers bearing against each other at their second ends, the moment arm from the pivot point of each of the third and fourth levers at its point of contact with the respective projection being equal to the moment arm from said pivot point to the point of contact with the other one of the third and fourth levers. .Iaddend. .Iadd. 7. A gas compressor or blower according to claim 6 in which the first and third bearing surfaces are on opposite sides of said first projection and said second and fourth bearing surfaces are on opposite sides of said second projection. .Iaddend..Iadd. 8. A gas compressor or blower according to claim 6 further including means for biasing the two bell crank levers in opposite senses of rotation that will in each case bias the first ends of the associated levers towards the respective bearing surfaces. .Iaddend..Iadd. 9. A gas compressor or blower according to claim 8 in which the biasing means is a tension spring extending between respective ones of said arms of the two bell crank levers. .Iaddend.