MULTIPIECE HAMMER FOR HAMMER MILLS
Hammers, including hammer blades, for hammer mills are shown which have an insert bushing press fit into a hole in each hammer blade so that the hammer blades rotate with the bushing around rods being rotated in a circle around a central rotary axis of the rotor of a hammer mill.
1 . Apparatus comprising:
at least one hammer blade for a hammer mill, said at least one hammer blade having an opening disposed through one end thereof corresponding to a pivot axis, said opening being of a first diameter;
a sleeve having a central opening therein, the sleeve being disposed in said opening in the one end of the at least one hammer blade;
said sleeve having a cylindrical outer surface having a second diameter slightly larger than the first diameter of the opening of the hammer blade, whereby the outer surface of the sleeve is at least initially in a press fit relationship with the inside of the opening of the hammer blade; and
wherein the central opening in the sleeve is of a third inner diameter of a size adapted to be rotatably disposed on a rod of a hammer mill.
2 . The apparatus of claim 1 wherein the sleeve is solid throughout the entire periphery thereof.
3 . The apparatus of claim 1 wherein the sleeve is made of spring steel and has a space between adjacent edges along a periphery thereof whereby the sleeve has an initial diameter larger than the first diameter of the opening in the hammer blade and can be squeezed to a smaller diameter, inserted into the opening of the hammer blade and then released and move to a larger diameter which forms a tight fit with the inside of the opening in the hammer blade.
4 . The apparatus of claim 1 wherein a plurality of hammer blades are disposed on the sleeve.
5 . The apparatus of claim 4 wherein a spacer is disposed between each adjacent hammer blade.
6 . The apparatus of claim 4 wherein there are five hammer blade on the sleeve.
7 . The apparatus of claim 1 wherein the sleeve is disposed on a rod between two plates of a hammer mill, each end of the sleeve being sealed against a respective one of the plates to prevent particles of the material being ground by the hammer mill from lodging between the sleeve and the rod.
8 . The apparatus of claim 7 wherein the respective ends of the sleeve are in abutment with respective plates of the hammer mill.
9 . The apparatus of claim 7 wherein that part of the hammer blade forming the opening therein is not in contact with the hammer mill rod but instead is in direct contact with the sleeve.