Fluid operated shears

A hand-held, fluid-operated shears unit for providing substantial cutting force without undue force being applied by a user of said shears unit, which comprises:

• an elongated body member with an axis, said body member having a rearward portion including a rearward end, and a forward portion including a forward end, said body member provided with an internal cylindrical surface defining a cylinder for receiving a reciprocatable piston, said cylinder having an axis parallel to said axis of said body member, said cylinder provided with a forward port and a rearward port;
• a pair of spaced-apart support plates carried by said forward end, said support plates extending in a direction parallel to said axis;
• a first blade releasably attached to at least one of said support plates, said first blade extending in a direction substantially parallel to said axis;
• a second blade pivotally and releasably attached to at least one of said support plates, said second blade positioned on a pivot member to cooperate with said first blade to provide a cutting action when said second blade is pivoted toward said first blade;
• a piston slidably positioned within said cylinder of said body member for reciprocation between a forward position and a rearward position;
• a piston rod having an axis parallel with said body member axis, said forward body portion provided with a channel to slidably receive said piston rod, said piston rod having a rearward end attached to said piston, and a forward end extending from said forward end of said forward body portion;
• linkage means having a first end and a further end, said first end pivotally attached to said forward end of said piston rod, and said further end pivotally attached to said second blade whereby reciprocation of said piston rod within said channel causes said second blade to pivot with respect to said first blade;
• a master valve mounted within said body member and oriented substantially perpendicular to said body axis, said master valve having a plurality of ports and an axially slidable valve stem, said valve stem having an extension projecting exterior to said body member, one of said valve ports being in communication with said forward port of said cylinder, a second of said valve ports being in communication with said rearward port of said cylinder, a third of said valve ports being in communication with a source of pressurized fluid, and a forth of said valve ports being in communication with a vent from said body member;
• a spring member associated with said master valve for normally biasing said valve stem to a position whereby said source of pressurized fluid is in communication through said first and third valve ports to said forward port of said cylinder whereby said second blade is pivoted away from said first blade;
• and
• lever means having a first end pivotally attached to said body member, and a second end, said lever member engaged with said exposed end of said valve stem extension whereby when said lever means is moved toward said body member by said user, said lever member moves said valve stem against said spring thereby causing said source of pressurized fluid to be in communication, through said second and third valve ports, to said rearward port of said cylinder whereby said second blade is pivotally moved into engagement with said first blade to effect cutting action therebetween.

A hand-held, hydraulically-operated shears unit for use in the processing of poultry, said shears unit providing substantial cutting force without undue force being applied by a user of said shears unit, which comprises:

• an elongated substantially cylindrical body member with an axis, said body member having a rearward portion including a rearward end, and a forward portion including a forward end, said body member provided with an internal cylindrical surface defining a cylinder for receiving a reciprocatable piston, said cylinder having an axis parallel to said axis of said body member, said cylinder provided with a forward port and a rearward port;
• a bracket member fastened to said forward end of said body member;
• a pair of spaced-apart support plates carried by said bracket, said support plates extending in a direction parallel to said axis;
• a first blade releasably attached to at least one of said support plates, said first blade extending in a direction substantially parallel to said axis;
• a second blade pivotally and releasably attached to at least one of said support plates, said second blade positioned on a pivot member to cooperate with said first blade to provide a cutting action when said second blade is pivoted toward said first blade;
• a double-acting piston cup slidably positioned within said cylinder of said body member for reciprocation between a forward position and a rearward position;
• a piston rod having an axis parallel with said body member axis, said forward body portion provided with a channel to slidably receive said piston rod, said piston rod having a rearward end attached to said piston, and a forward end extending from said forward end of said forward body portion;
• linkage means having a first end and a further end, said first end having a pair of legs pivotally attached to said forward end of said piston rod, and said further end pivotally attached to said second blade whereby reciprocation of said piston rod within said channel causes said second blade to pivot with respect to said first blade;
• a master valve mounted within said body member and oriented substantially perpendicular to said body axis, said master valve having a plurality of ports and an axially slidable valve stem, said valve stem having an extension projecting exterior to said body member, one of said valve ports being in communication with said forward port of said cylinder, a second of said valve ports being in communication with said rearward port of said cylinder, a third of said valve ports being in communication with a source of pressurized fluid, and a forth of said valve ports being in communication with a vent from said body member;
• a spring member associated with said master valve for normally biasing said valve stem to a position whereby said source of pressurized fluid is in communication through said first and third valve ports to said forward port of said cylinder whereby said second blade is pivoted away from said first blade;
• and
• lever means having a first end pivotally attached to said body member, and a second end, said lever member engaged with said exposed end of said valve stem extension whereby when said lever means is moved toward said body member by said user, said lever member moves said valve stem against said spring thereby causing said source of pressurized fluid to be in communication, through said second and third valve ports, to said rearward port of said cylinder whereby said second blade is pivotally moved into engagement with said first blade to effect cutting action therebetween.