System for removing a knife insert from the knife holder of a grinder

A knife insert for use with a knife holder of a grinder, such as a meat grinder, is adapted to be positioned within a slot formed in the knife holder. The knife insert extends outwardly from the outer end of the knife holder, and a beveled edge is formed adjacent the outer end of the knife insert. The beveled edge is adapted to be engaged by a punch, which is struck such as by a hammer to dislodge the knife insert from the knife holder when it is desired to change knife inserts. The beveled edge enables the punch to be held at an angle relative to the knife holder and the adjacent components of the grinder, to allow the punch to easily be held in place. The hammer, which is used to apply the striking force to the punch, can easily be swung clear of the components of the grinder head to facilitate easy and quick removal of the knife insert.

BACKGROUND AND SUMMARY OF THE INVENTION 
This invention relates to a grinder which employs a rotating knife assembly 
in combination with an orifice plate or the like, and more particularly to 
a system for removing knife inserts from the knife assembly. 
A heavy duty grinder, such as a meat grinder, typically includes a housing 
having an outlet, with an orifice plate being mounted to the housing at 
its outlet. The material to be ground is forced through the housing toward 
the outlet, such as by a rotating auger. A knife assembly, which generally 
consists of a knife holder having a series of knife inserts mounted 
thereto, is rotatably mounted adjacent the inside surface of the orifice 
plate such that the knife inserts bear against the orifice plate during 
rotation of the knife assembly. Typically, the knife assembly is mounted 
to the end of the auger, and rotates along with the auger to sever the 
material as it is being forced into and through the individual orifices of 
the orifice plate. 
The knife holder includes slots within which the knife inserts are 
received. The knife inserts wear relatively rapidly, and it is necessary 
to frequently change the knife inserts during operation of the grinder. 
Typically, a buildup of material occurs within the knife holder slots, 
which makes it difficult to remove the knife inserts prior to installation 
of replacement inserts. 
The knife holder typically includes a series of radial arms extending 
outwardly from a hub, with each arm terminating in an outer end. A slot is 
formed in each knife holder arm, opening onto the outer end of each arm. 
In the past, the knife insert has extended outwardly of the outer end of 
each arm, and a notch has been formed in the knife insert. The notch 
defines a striking surface parallel to the longitudinal axis of the knife 
insert. To remove the knife insert, a punch has been engaged with the 
striking surface defined by the notch and the punch has been struck, such 
as by using a hammer or the like, to break the knife insert free from the 
material accumulated within the slot to remove the knife insert from the 
slot. The orientation of the striking surface on the knife insert has made 
it difficult to accurately position the punch and to allow an accurate 
swing of the hammer with sufficient force to quickly and easily break the 
knife insert free. 
It is an object of the present invention to provide a knife insert 
structure which facilitates removal of the knife insert from the knife 
holder when changing knife inserts, using a conventional knife holder and 
without providing a departure from the manner in which the knife inserts 
are mounted to the knife holder. Another object of the invention is to 
provide a quick and easy method of removing the knife inserts from the 
knife holder. 
In accordance with one aspect of the invention, a knife insert for a 
grinder defines a forward edge extending outwardly of the knife holder 
slot, a rearward edge disposed within the slot, and inner and outer ends. 
The knife insert extends along a longitudinal axis, and includes a beveled 
edge oriented non-parallel to the longitudinal axis. The beveled edge 
forms at least a part of the outer end of the knife insert. The beveled 
edge is adapted to be engaged by a striking tool having its longitudinal 
axis oriented non-perpendicular to the longitudinal axis of the knife 
insert for use in removing the knife insert from the slot. The outer end 
of the knife insert further includes an outer edge which extends 
rearwardly from the forward edge, and the beveled edge extends between the 
rearward edge and the outer edge. Preferably, the beveled edge is oriented 
at an angle of approximately 30.degree. relative to the rearward edge. The 
knife insert extends outwardly from the outer end of the knife holder arm 
to which it is mounted. The beveled edge of the knife insert is formed so 
as to extend inwardly from the outer end of the knife holder into the 
slot. With this arrangement, the end of the striking tool is engaged with 
the beveled edge and the striking tool is then struck to remove the knife 
insert from the knife holder slot, by application of a force applied in a 
direction substantially perpendicular to the beveled edge. The striking 
tool can thus be positioned so as to extend outwardly away from the knife 
holder, to facilitate engagement of the tool with the beveled edge and 
striking of the tool with a hammer or the like. No modifications to the 
knife holder structure are necessary in order to accommodate the improved 
knife insert and to facilitate its removal from the knife holder. 
The invention also contemplates a method of removing a knife insert from 
the knife holder of a grinder, substantially in accordance with the 
foregoing summary.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 1 illustrates a knife assembly, shown generally at 10, adapted for use 
in a heavy duty grinder, such as a meat grinder or the like. Knife 
assembly 10 consists of a knife holder having a hub 12 and a series of 
arms extending therefrom, shown at 14a, 14b, 14c and 14d. The knife holder 
may be that such as is shown and described in pending U.S. application 
Ser. No. 07/778,010, filed Oct. 17, 1991, the disclosure of which is 
hereby incorporated by reference. 
Arms 14a-14d are identical in construction. Each of arms 14a-14d is 
provided with a slot extending from hub 12 throughout its length, opening 
onto the outer end of each arm. The slots in arms 14a-14d are shown at 
16a-16d, respectively. Knife inserts, such as shown at 18a-18d, are 
mounted within slots 16a-16d, respectively, in arms 14a-14d. Each of slots 
16a-16d is slanted forwardly relative to the outer surface of each arm 
14a-14d onto which the slot opens, such that knives 18a-18d are slanted 
forwardly in the direction of rotation of knife assembly 10. 
FIG. 2 illustrates the structure of a prior art knife insert shown at 20. 
Insert 20 is adapted for use with a knife holder identical to that shown 
in FIG. 1. Knife insert 20 includes a sharpened forward edge 22, a 
rearward edge 24 parallel to forward edge 22, an inner end 26 including an 
inner edge 28 and an angled edge 30 extending between inner edge 28 and 
rearward edge 24, and an outer end 32 including an outer edge 34 and a 
notch 36 defining a striking surface 38 and an edge 40 extending between 
striking surface 38 and rearward edge 24. Striking surface 38 is oriented 
parallel to the longitudinal axis of insert 20 and to forward and rearward 
edges 22, 24, respectively. A notch 42 is formed in rearward edge 24 
adjacent angled edge 30, for receiving a pin 43 (FIG. 4) located within 
each of slots 16a-16d within which knife 20 is adapted to be received, for 
positioning knife insert 20 in a proper lateral position relative to knife 
arms 14a-14d, respectively. 
FIG. 3 illustrates knife insert 20 engaged within the slot formed in one of 
arms 14a-14d, in which the arm is shown generally at 14. When it is 
desired to remove insert 20, an operator positions a conventional punch, 
the tip of which is shown at 44, such that the end of punch 44 engages 
striking surface 38 and punch 44 extends along a longitudinal axis 
substantially perpendicular to striking surface 38 and to the longitudinal 
axis of knife insert 20. The operator then applies a striking force to 
punch 44, such as by use of a hammer or the like, in the direction of an 
arrow 46 to dislodge knife insert 20 from the slot 16 formed in arm 14. 
This lifts the outer end of knife insert 20 upwardly out of slot 16 and 
away from arm 14. Angled surface 30 accommodates the upward lifting 
movement of the outer end of knife insert 20 until knife insert 20 has 
been moved out of slot 16 an amount sufficient to enable the operator to 
grasp knife insert 20 and physically pull the remaining portion of knife 
insert 20 out of slot 16. As noted previously, the drawback to this 
procedure is that it is difficult to position punch 44 in the manner shown 
and to enable the operator to maneuver the hammer in a manner sufficient 
to apply the necessary striking force to punch 44 in order to quickly and 
easily dislodge knife insert 20. 
Referring to FIG. 4, one of knife inserts 18a-18b constructed according to 
the invention, shown generally at 18, includes a forward edge 50, a 
rearward edge 52, and an inner end 54 including an inner edge 56 and an 
angled surface 58 extending between inner edge 56 and rearward surface 52. 
A notch 60 extends inwardly into knife insert 18 from rearward edge 52. 
This portion of knife insert 18 is substantially identical to the 
analogous portions of knife insert 20 as described previously. 
The outer end of knife insert 18, shown at 62, consists of an outer edge 64 
and a beveled edge 66. Outer edge 64 extends rearwardly from forward 50, 
substantially perpendicular thereto, approximately one-half the height of 
knife insert 18. Beveled edge 66 extends between outer edge 64 and 
rearward edge 52, with a radius being formed between outer edge 64 and 
beveled edge 66. Beveled edge 66 is oriented at an angle of approximately 
30.degree. relative to rearward edge 52. 
FIG. 5 illustrates the manner in which knife insert 18 is mounted to one of 
arms 14a-14d, shown generally at 14. As with knife insert 20, outer end 62 
of knife insert 18 extends outwardly beyond the outer end of arm 14. 
Beveled edge 66 extends inwardly within slot 16. 
When it is desired to remove knife insert 18, the flat end of a punch 68 is 
positioned against beveled edge 66. Punch 68 is relatively thin, allowing 
it to fit within slot 16 and to provide a significant amount of contact 
with beveled edge 66. Additionally, engagement of punch 68 within slot 16 
functions to positively retain punch 68 in alignment with beveled edge 66. 
Punch 68 is then struck using a hammer or the like to apply a force along 
the direction of arrow 70, to dislodge knife insert 18 from slot 16 in 
knife arm 14. Punch 68 thus exerts a force on knife insert 18 in a 
direction non-perpendicular to the longitudinal axis of knife insert 18. 
Punch 68 is continued to be struck until knife insert 18 attains a 
position as shown in FIG. 6, in which the outer end of knife insert 18 is 
lifted out of slot 16 sufficiently to allow the operator to grasp knife 
insert 18 and draw it out of slot 16 using manual force. Again, as with 
knife insert 20, angled surface 58 accommodates such upward movement of 
the outer end of knife insert 18. 
Punch 68 can be easily positioned as shown in FIG. 5, enabling an operator 
to retain the punch in position without interference from the remaining 
components of the grinder head to which knife assembly 10 is adjacent. 
Further, the hammer which is swung to strike punch 68 is clear of all 
components of the grinder head, allowing an operator a clear and easy 
swing at punch 68 in order to easily remove knife insert 18. 
Various alternatives and embodiments are contemplated as being within the 
scope of the following claims particularly pointing out and distinctly 
claiming the subject matter regarded as the invention.