Method of making a hammer mill hammer with grooves for receiving hard facing material

Abstract

An improved hammer mill hammer constructed by forming a groove in an edge of the grinding end of a hammer for receiving hard facing material and placing hard facing in the groove.

Claims

1. A method of making a hammer having a rod hole end having a rod hole disposed therein and wherein the rod hole is configured to engage a hammer mill rod so that the hammer can move about an axis extending through the rod hole; a grinding end being spaced from the rod hole end of the hammer, the grinding end having a length, a width, and a thickness defined between a first face and a second face of the hammer; an edge extending from the first face to the second face about opposing sides of the length of the grinding end and the width of the grinding end; a neck connecting the rod hole end and the grinding end; the method comprising: forming a continuous groove in the edge about the opposing sides of the length of the grinding end and the width of the grinding end for receiving hard facing material such that a plane, disposed transverse to the axis extending through the rod hole, intersects the continuous groove along a length and width of the continuous groove, the plane also intersecting the rod hole; and applying a layer of hard facing in the continuous groove.

2. The method of claim 1 wherein the continuous groove along the width of the grinding end is formed at least partially along a first straight line and at least partially along a second straight line wherein the second line is spaced from, but parallel to, the first line and both the first and second line are disposed in the plane.

3. The method of claim 2 wherein the continuous groove about the length of the grinding end is positioned transversely to the first straight line.

4. The method of claim 3 wherein the continuous groove is configured so that a centermost portion of the continuous groove, disposed along the second line, is positioned closer to the neck than the first line.

5. The method of claim 4 wherein the centermost portion of the groove is made to form a pocket between the opposing sides of the length of the grinding end.

6. The method of claim 1 wherein tungsten carbide is used as at least part of the hard facing.

7. The method of claim 1 comprising using tungsten carbide as the hard facing material and applying the tungsten carbide hard facing using a welding process.

8. The method of claim 1 comprising applying a second layer of hard facing over the layer of hard facing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 1. The above identified problem is at least partially solved through provision of the method and apparatus described in the following detailed description, particularly when studied in conjunction with the drawings, wherein:

(2) FIG. 1 is a front elevational view of a hammer constructed in accordance with the present invention before hard facing is attached thereto;

(3) FIG. 2 is a side elevational view of the hammer of FIG. 1;

(4) FIG. 3 is an enlarged side elevational view of the grinding end taken along line 3-3 of FIG. 1;

(5) FIG. 4 is a cross sectional view of the grinding end taken along line 4-4 of FIG. 1;

(6) FIG. 5 is a front elevational view like FIG. 1 but having hard facing attached in the grooves and around the edges of the grinding end of the hammer;

(7) FIG. 6 is a side elevational view of the hammer of FIG. 5;

(8) FIG. 7 is an enlarged side elevational view of the grinding end taken along line 7-7 of FIG. 5;

(9) FIG. 8 is a cross sectional view of the grinding end taken along line 8-8 of FIG. 5;

(10) FIG. 9 is an enlarged perspective view of the hammer as shown in FIGS. 1-4 before hard facing is attached thereto;

(11) FIG. 10 is an enlarged perspective view of the hammer as shown in FIGS. 5-8 after hard facing is attached thereto.

DETAILED DESCRIPTION OF THE INVENTION

(12) Referring to the drawing, wherein like reference numerals designate identical or corresponding parts throughout the several figures, FIG. 1.

(13) FIGS. 1-4 and 9 show a blank hammer before hard facing is attached as shown in FIGS. 5-8 and 10.

(14) Referring now specifically to FIGS. 1-4, a hammer (10) is shown with a rod hole end (11) having a rod hole (12) disposed therein. The rod hole (12) is configured to engage said hammer (10) with a hammer mill rod (10r). A grinding end (13) is spaced from the rod hole end (11) along a length of said hammer (10). The grinding end (13) has a length (131) (FIG. 2), a width (13w) (FIG. 1), and a thickness (13t) defined between a first face (13f1) and a second face (13f2) (FIG. 4). The grinding end (13) also has a second face (13f2) with an edge (13e) (FIG. 3) disposed between the first face (13f1) and the second face (13f2).

(15) A neck (14) connects the rod hole end (11) and said grinding end (13). The grinding end (13) is disposed in a plane (10p) (FIG. 2), the plane (10p) being between the first face (13f1) and the second face (13f2) of the grinding end (13). The plane (10p) also intersects the edge (13e) of the grinding end (13).

(16) A groove (13gl) is formed in the edge (13e) for receiving hard facing material (20). Hard facing (20) disposed in the groove (13gl), preferably my moving a welder (30), along a path (30p) shown in dashed lines in FIG. 1. Adding multiple thin layers of hard facing (20), each layer extending over the last layer added, such as welding with a material that includes tungsten carbide, rather than just one big thick layer of hard facing, has been found to make the bond between the grinding end (13) of the hammer and the welded hard facing much stronger. This is in addition to the fact that placing the hard facing in a groove (13g) also holds the welded hard facing (20) to the grinding end (13) much better than when applied to a grinding end that does not have a groove in it. The method of applying hard facing (20) in its most basic form is applying a first layer of hard facing (20) in the groove (13gl) and then applying a second layer of hard facing (20) over the first layer of hard facing. Additional layers can be added over the last layer applied by a welder (30) passing redundantly along a path (30p) as shown in FIG. 1.

(17) Looking again at FIG. 1, it is noted that the rod hole is elliptical, with the top arc of the elliptical hole 12 being formed by a radial arc (12ra) rotated about a point (12caa). Similarly, the bottom arc of the elliptical hole 12 is formed by a radial arc (12rb) rotated about a point (12cab). Other configurations of the rod hole can be used, for example in the shapes disclosed for co-pending U.S. patent application Ser. No. 15/093,199 to Chad Plumb, filed Apr. 7, 2016.

(18) FIG. 2 shows a hammer mill rod (10r) in dashed line, the hammer mill rod (10r) having a centerline (10c1). When the hammer (10) is hanging in the position shown in FIG. 2 and most of the time when the hammer mill is in operation, the rod (10r) will be in contact with the arc formed by radial arc (12ra) shown in FIG. 1, leaving a space between the rod (10r) and the lower part of the rod hole formed by the lower radial arc (12rb) as shown in FIG. 1. This space (12s) (FIG. 2) between the rod and the rod hole prevents the buildup of material between the rod (10r) and the rod hole (12) and also makes it easier to remove the hammer (10) when desired.

(19) The grinding end (13) of the hammer (10) is connected to the neck (14) at one end place (13ep1) (FIG. 9) of the length (131) of the grinding end (13), that one end place (13ep1) being a connected to the neck end. The other end place (13ep2) being a free end spaced from the neck (14).

(20) The edge (13e) of the grinding end (13) extends at least partially along the length (131) of the grinding end (13), on at least one side of the grinding end (13) and the groove is disposed in the edge (13e) of the grinding end (13) that extends at least partially along the length (13l) of the grinding end (13).

(21) The edge (13e) of the grinding end (13) also, optionally, extends at least partially along the width (13w) of the grinding end (13), at the other end place (13ep2), which is the free end spaced from the neck (14). The groove part (13gl) is disposed in the edge (13e) of the grinding end (13) that extends (13ga, 13gb, 13gd, 13ge, 13gf, 13gg) at least partially along the width (13w) of the grinding end (13).

(22) The edge (13e) of the grinding end (13) extends completely across and along the width (13w) of the grinding end (13) and the groove (13ga, 13gb, 13gd, 13ge, 13gf, 13gg) extends entirely across the entire width (13w) of the grinding end. The groove (13ga, 13gb, 13gd, 13ge, 13gf, 13gg) that extends entirely across the entire width (13w) of the grinding end is disposed in said plane (10p) as shown in FIG. 2.

(23) The groove (13ga, 13gb, 13gd, 13ge, 13gf, 13gg) that extends entirely across the entire width (13w) of the grinding end is also disposed in the plane (10p) and has a first portion (13gh) that is disposed at least partially along a first straight line (13sla) and at least partially along a second straight line (13slb) wherein the second line (13slb) is spaced from, but parallel to, the first line (13sla). Both the first (13sla) and second line (13slb) are disposed in the plane (10p).

(24) A centermost portion of the groove (13gd) is disposed along the second line (13slb) closer to the neck (14) than the first portion (13gh) of the groove. The centermost portion of the groove (13dg) has a first wall of a pocket (13p) (FIGS. 1, 9 and 10) formed between a left and right side of the free end (13ep2).

(25) FIGS. 5-8 and 10 show the hard facing material (20), filling the groove (13gl) and covering the edge (13e) with welded hard facing that preferably includes tungsten carbide as at least part of the hard facing material.

(26) Using the grooves (13gl) or pockets of the present invention for hard facing allows for multiple passes of hard-facing with a narrow hammer body for less power consumption. Designed raised edges of hard facing keep hammer sharp for low horsepower start up and improved fine grinding.

(27) Using the elliptical rod hole (12) of the present invention allows for easy clean out of the hole which minimizes hammer sticking and rod wear and allows for faster installation and removal.

(28) Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept as expressed by the attached claims.