Metal demolition shears

A heavy duty scrap metal shear for attachment to the boom structure and hydraulic system of a back hoe, said shear comprising:

• (a) a lower jaw and an upper jaw with pivot means interconnecting the jaws together, including means for attaching said shear to the hydraulic system of the back hoe for closing and opening the upper jaw relative to the lower jaw;
• (b) the upper jaw further comprising a rigid upper shear blade extending along said upper jaw, the lower jaw having a lower shear blade extending along said lower jaw, said upper and lower shear blades of sufficient strength for shearing a workpiece of scrap metal when the upper shear blade is closed relative to the lower shear blade;
• (c) the upper and lower shear blades further comprising inner and outer workpiece engaging portions opposite to each other, the inner and outer workpiece engaging portions of the upper shear blade extending obliquely of each other;
• (d) the lower shear blade also having a lower shear plate and a rigid guide plate lying along and spaced from the lower shear plate;
• (e) an outer end closure member affixing the lower shear plate and the guide plate to each other at their free ends and serving to define an open slot between the lower shear plate and guide plate to receive the upper jaw therein, said open slot being wider than the width of the upper jaw to maintain a clearance between the upper jaw and the lower shear plate and guide plate when the upper jaw traverses the open slot;
• (f) said upper and lower shear blades further comprising at least one upper and at least one lower detachable elongate rigid knife seating means affixed to the upper and lower jaws, respectively, said upper and lower knife seating means adapted to provide securable seating means for at least one upper and at least one lower knife blade means, respectively;
• (g) said upper knife blade means being detachably secured to said upper knife seating means, said upper knife seating means being detachably secured to the upper jaw, thereby forming an upper planar shearing surface;
• (h) said lower knife blade means being detachably secured to said lower knife seating means, said lower knife seating means being detachably secured to the lower shear plate adjacent to the open slot, thereby forming a lower planar shearing surface;
• (i) the upper and lower shearing surface being adapted to be slidably engageable with each other during the shearing movement of the upper shear blade relative to the lower shear blade.