Slicer knife guard and sharpener

Slicing machine has a protective knife or blade edge guard for that portion of the periphery of the circular knife which is not coverable by the conventional gauge plate during sharpening of the knife edge or cleaning of the face and rearside of the knife. The blade edge guard is fastened to a bearing block for the shaft which supports and drives the knife, by means of spaced spokes extending from the block to the guard. A parallel pair of the spokes support slotted plates which mount a knife sharpener having stones for grinding and honing the edge of the knife. The sharpener has fixed pins on a body portion thereof, which pins cooperate with open-ended slots in said plates to enable the sharpener to be readily moved between inactive and active positions and removable for cleaning, all with one hand positioning or movement of the sharpener.

BACKGROUND OF THE INVENTION 
This invention relates generally to a food product slicer of the type 
having a rotatable circular or disc-like slicing knife, a gauge plate 
along one edge of the knife for determining the thickness of slices and a 
carriage, generally perpendicular to the face of the knife, for supporting 
food product as it is moved past the cutting edge of the knife during 
slicing. The invention relates to a means for guarding the periphery of 
the knife in combination with a knife sharpener carried by a portion of 
the guarding means. The guard is mounted on the slicing machine in a 
fashion which prevents removal thereof except under conditions where the 
knife itself is first removed. The invention additionally relates to a 
specific knife sharpener which can be easily moved between an inactive 
position and an active sharpening position and easily removed from the 
sharpener supporting means for cleaning remote from the machine, all with 
one hand. The sharpener is mountable on a portion of the means which 
supports the knife edge guard to provide for ease of manufacturing and 
accuracy of positioning the sharpener relative to a relieved or notched 
portion of the knife edge guard. 
DESCRIPTION OF THE PRIOR ART 
A number of commercial food slicers exist having knife edge guards which 
encompass approximately 360.degree. of the edge of a circular knife. Some 
of these slicers also comprise top-mounted knife sharpeners. European 
Patent No. 90,064, issued on May 28, 1986, illustrates a slicer having the 
blade edge guard extending around approximately 240.degree. of the knife. 
The gauge plate can be positioned to cover essentially the remaining 
120.degree.. The system further includes notched-out relief portions in 
the edge guard so that a top-mounted sharpener can have its sharpening 
stones engage the front and rear faces of the cutting edge to grind and 
hone a fine edge. The sharpener is removable to enable its being cleaned 
at a location away from the slicing machine. 
Another relevant prior art slicer is disclosed in U.S. Pat. No. 3,124,185 
granted to E. C. Karp on Mar. 10, 1964. Karp appears to show a blade edge 
guard mounted from a motor housing by a partially-open rear guard 
framework to enable cleaning of the rear side of the knife. A portion of 
the framework supports a quick-detach handle assembly which in turn 
supports a front guard plate. The assembly and front plate can be removed 
together when the knife is to be sharpened, temporarily exposing a segment 
of the knife edge until a sharper is removed from a storage location and 
placed in the position formerly occupied by the handle assembly. An 
alternative embodiment which is described in Karp has the sharpener 
mounted on the slice thickness gauge plate while it is set to its maximum 
thickness setting, thus exposing about 120.degree. of the sharp knife edge 
during blade sharpening. 
In addition, a sharpener is disclosed in U.S. Pat. No. 3,958,478 issued to 
William Camper on May 25, 1976 and assigned to Assignee of the present 
invention. That patent shows a sharpener which is movable by hand between 
inactive and active positions, but ordinarily requires the operator to use 
both hands on the sharpener during removal for cleaning. 
It would be desirable to provide a slicer which improves over the prior art 
in respect of the mounting structure for the blade edge guard and knife 
sharpener, whereby the slicer can be readily cleaned and can be more 
easily manufactured and assembled. It would be further desirable to 
provide a sharpener mounting arrangement which permits the sharpener to be 
removed for cleaning in a single-handed operation. 
SUMMARY OF THE INVENTION 
One aspect of this invention relates to a protective slicer blade edge 
guard supported from a motor housing by means of spokes supporting both 
the guard and a knife sharpener. Certain of the spokes mount a knife 
sharpener for movement between inactive and active positions and easy, 
one-hand removal from the supporting means for cleaning. With respect to 
the peripheral portion of the blade normally used for slicing, i.e., the 
area adjacent a thickness gauge plate, in order to prevent contact with 
that area during sharpening, the gauge plate is to be placed in its "zero 
thickness" position so that it covers the knife edge in the area not 
encompassed by the blade edge guard. A generally circular surface plate is 
also mounted on the blade edge guard and covers the entire area of the 
face of the knife during a slicing operation, except for the area adjacent 
the cutting edge cross which food product passes during slicing. Such 
plates are common in the art. The latter plate is easily removable from 
the blade edge guard to enable cleaning of the face of the knife in its 
entirety after a slicing operation has been performed. The mounting means 
for supporting the blade edge guard consists of spokes which enable a 
large portion of the rearside of the knife to be exposed for hand cleaning 
by wiping with a cloth or other cleaning instrument. The sharpener is 
detachably mounted on side plates fastened to parallel ones of said spokes 
and is provided with pairs of laterally-protruding fixed pins. The pins 
engage in slots in the side plates to guide the sharpener for hand 
movement between its active and inactive positions. The slots are 
open-ended to the outer edges of the side plates to enable easy, one hand 
removal of the sharpener for cleaning.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A circular of disc-like slicing blade or knife 10 and a slice thickness 
gauge plate 11 are shown in dotted lines in FIG. 1 and in full lines in 
FIG. 4. They are conventional and are mounted on a base of a slicing 
machine. The machine conventionally includes a product-supporting carriage 
(not shown) which is reciprocated either manually by the slicing machine 
operator or driven by a motor in the case of an automatic slicer. Since 
all of these elements are old and well-known in the art, they will be 
described only briefly herein, it being understood that the knife is 
mounted for rotation on a fixed-axis shaft and the gauge plate is movable 
essentially laterally with respect to the plane of the knife for 
predetermining slice thickness. The gauge plate can also be located to the 
"zero" position wherein it encompasses or covers the periphery of the 
knife edge as shown in FIG. 3. With the gauge plate 11 in the covering 
position, a sharpener, generally designated by the numeral 12 in FIG. 3, 
can be moved to an active, sharpening position on the machine to "touch 
up" the knife edge by grinding along the outer rear face of the knife and 
finally honing the front edge or face to remove any burrs created by the 
grinding action. 
The gauge plate 11 covers approximately one-third of the peripheral edge of 
the knife during the sharpening or cleaning operations. An edge guard 13 
is supported by four spokes 14-17 in spaced-apart fashion so that a major 
portion of the underside or rear of the blade 10 is exposed for wiping as 
can be seen in FIG. 4. The outward ends of the spokes 14 and 15 have studs 
18 and 19 welded thereto. Spokes 16 and 17 are welded to an edge protector 
20, as at 21 and 22. The upper edge of the blade edge guard 13 is also 
welded to the edge protector 20 at 23. It can be seen, therefore, that 
blade edge guard 13, spokes 16 and 17 and edge protector 20 are integral, 
as by welding, for purposes to becomes apparent later. These elements are 
accurately held within an accurate fixture (not shown) during the welding 
operation. Edge guard 13 may be formed of flat metal stock. The guard 13 
is L-shaped in cross-section as shown in FIG. 7 and is formed to its 
circular configuration prior to its being interconnected with a generally 
known edge protector 20. The ability to form the guard 13 of a flat strip 
of stock allows it to be made more economically than if machined from 
solid stock. The edge protector 20 performs similarly in some respects to 
that disclosed in EPO Patent 90,064 by providing relieved portions to 
allow for knife contact by sharpening and honing stones. The protector 20 
provides an extension at one end of the edge guard 13. Relief 24 in 
protector 20 provides a notched portion in the blade edge guard to allow 
the sharpening wheel 25 shown in FIGS. 5 and 6 to grind the rear side of 
the edge of the knife when dressing its edge. Relief 26 provides a similar 
notched portion to allow contact by a honing stone 27 with the outer edge 
of the knife face, in order to create an extremely sharp edge after 
grinding has been done. Sharpening wheel 25 and honing stone 27 are 
engaged either simultaneously or successively by means of a person holding 
down on a hood 28 of the sharpener 12 when it is in active sharpening 
position and pressing with the thumb and one finger against buttons 29 and 
30 in conventional fashion. Wheel 25 and stone 27 are spring-loaded away 
from the knife, and the spring bias is overcome by pressing lightly on 
buttons 29 and 30 to dress the edge of the knife while it is rotating. 
This sharpening method is common in the slicing machine art and need not 
be described in greater detail. 
The spokes 14-17 are mounted in holes provided radially inwardly of a 
bearing block or hub 31 for the shaft 32 of a motor (not shown) mounted 
within housing 33. As shown in FIG. 3, the shaft 32 which drives the knife 
10 has a nut or other fastener 34 for holding the knife 10 against a 
shoulder on the shaft. The shaft 32 is mounted in bearings (not shown) 
received in recessed bores 35 and 36 of hub 31 (FIG. 2). Design and 
construction is such that hub 31 must be removed from the housing 33 in 
order to enable the edge guard 13 to be removed from the machine with the 
spokes. It can be seen that the spokes 14-17 may be pinned to the hub 31 
as by pins 37 in FIG. 2, requiring that even the pins cannot be removed to 
allow the spokes to be removed from the hub 31 unless the hub is first 
removed from the housing 33. In order to remove the hub 31, knife 10 must 
first be removed from shaft 32 and shaft 32 and hub 31 removed with the 
spokes and edge guard 13 as a unit, all as shown in solid lines in FIG. 1. 
The hub 31 is fastened to housing 33 by means of screws (not shown) 
passing through holes 53. For all practical purposes, the edge guard 13, 
block 31, edge protector 20 and spokes 14-17 are all interconnected once 
installed in a machine, and can be put into the machine during assembly or 
repair only prior to installation of the knife or can be removed from the 
machine only after the knife has been removed. 
Referring now to the sharpener 12 and its mounting means, a pair of flat 
side plates 38 and 39 are individually welded to spokes 16 and 17, 
respectively. This welding was accomplished at the time the spokes 16 and 
17, the edge protector 20 and the edge guard 13 were welded together in a 
fixture, to assume proper location and alignment of the elements. This 
allows the sharpener 12 shown in FIGS. 5 and 6 to be accurately positioned 
on the plates 38 and 39 by means of pairs of pins 40 and 41 which 
cooperate with pairs of slots 42-44 as shown in FIGS. 2 and 4. By 
referring to Camper U.S. Pat. No. 3,958,478, which patent is the 
predecessor design of the sharpener of this invention and is specifically 
incorporated by reference herein, it will be seen that (a) pins 40 and 41 
will be received in slots 42 and 44 respectively when the sharpener is in 
an inactive (non-sharpening or storage) position at the top and rear of 
the slicer knife during normal slicing operation, (b) pins 40 can be 
lifted out of slots 42 and moved into slots 43 while pins 41 just move up 
and down within slots 44 to move the sharpener 12 to the active sharpening 
position shown in FIG. 3, and (c) the sharpener 12 can be simply removed 
from the machine by disengaging pins 40 from either of slots 42 or 44, 
tipping it counterclockwise by passage through openings 45 shown best in 
FIG. 2 and dropping pins 41 downwardly out of the open end of slots 44 to 
remove the sharpener 12 from the machine. All of the aforementioned 
movements of the sharpener can be easily accomplished with one hand, and 
without operating any latching mechanism. Removal is frequently required 
to clean the sharpener at a sink to remove any meat and fat residue or 
metal particles ground from the surface of the knife. A key improvement of 
the sharpener of certain claims this invention with respect to that of the 
aforementioned Camper patent is that the openings 45 in the plates 38 and 
39 allow the one-hand operation during removal and installation of the 
sharpener. 
As can be seen particularly in FIG. 4, the sole support for the sharpener 
in both its active and inactive positions are the vertical side plates 38 
and 39. By being mounted via welding to spokes 16 and 17, the plates allow 
cleaning access between the spokes 16 and 17 as well as the areas on 
either side of any of the spokes 14-17. In addition, by assembling the 
plates 38 and 39, spokes 16 and 17, protector 20 and guard 13 in a fixture 
prior to welding all of those parts together, the slots 42 and 43 become 
very accurate guiding and positioning means for the pins 40 and 41. The 
bottoms of slots 42 and 43 provide steady positioning of the sharpener in 
its inactive and active positions, the latter of which is achieved prior 
to sharpening the knife. Proper slot-bottoming of the pins 40 in relation 
to the edge of the knife allows dressing of the cutting edge until such 
time that the diameter of the knife has reduced through repeated 
sharpening to a point at which the knife should be replaced. 
Shown in dotted lines in FIG. 1, a generally circular plate 47 is notched 
as at 48 and 49 to be received in necked-down portions of studs 18 and 19. 
The screws have their heads extending above the top surface of the blade 
edge guard 13 to accommodate capture of the plate 47 at notches 48 and 49. 
The left edge of the plate 47 is made essentially coplanar with the 
surface 50 of the knife face so that food product being sliced passes 
across the surface 50 and is supported by the plate 47. Plate 47 is 
essentially recessed within the area 51 of the knife as shown in FIG. 3. 
Latch means (not shown) is mounted on and carried by the plate 47 in the 
area of relief 26 of the edge protector 20 and is actuatable to engage 
with or disengage from a slot 52 (FIG. 4) to mount the plate 47 in fixed 
position during a slicing operation. The design of the plate 47 enables 
the latch means to be disengaged, plate 47 moved slightly outwardly and 
upwardly away from the face of the knife and rocked a small amount 
clockwise about stud 19. At that time, notch 48 will disengage from stud 
18. Notch 49 may then be disengaged from stud 19 by lifting the plate 47 
upwardly. Reinstallation of the plate 47 is done in reverse order, by 
first placing notch 49 over the the necked-down stud 19, rocking it 
counterclockwise until notch 48 engages over the necked-down stud 18, 
dropping the latch means into relief 26 and turning the latch to engage 
with slot 52 of the edge protector 20. Once latched, plate 47 has been 
fastened at three points to provide sufficient stability to support the 
weight of the product being sliced.