The invention concerns a meat tenderizing mechanism enclosed by a housing. The tenderizing mechanism includes two intermeshed roller assemblies which are driven by a manually rotated crank handle. Bladed disks of the roller assemblies are designed to tenderize a meat slice which is passed between the roller assemblies during unit operation. Stationary stripper plates are provided to remove a slice of meat from rotating bladed disks to prevent the meat from wrapping around the rollers. A receiving tray is located below the roller assemblies to catch the tenderized meat which may then be drawn from the housing for easy access to the tenderized meat.

The invention concerns a mechanical meat-tenderizer which is manually 
operated. 
The less expensive cuts of meat available to and often preferred by the 
general consumer tend to be tough and difficult to chew. To make these 
cuts of meat more palatable, different means have been proposed for 
tenderizing meat. Seasonings containing chemical tenderizers are commonly 
used to break down meat tissues and meat hammers are utilized to 
physically separate the tissues. However, a substantial number of 
consumers hesitate to add unnecessary chemicals to their food and other 
individuals consider the use of meat hammers to be too tedious. 
A mechanical beef tenderer is proposed in U.S. Pat. No. 386,226 to Welch 
having three rollers. Two of the rollers are smooth and free-wheeling, 
while the third roller is provided with teeth having flat faces and sides. 
The device is operated by the rotation of a crank handle as a piece of 
beef is fed horizontally between the smooth and toothed rollers such that 
the flat faces of the teeth strike and thus tenderize the beef. 
Bergstrom, in his U.S. Pat. No. 1,125,940 discloses a meat tenderer 
comprising a smooth roller and another roller having disks with cutting 
edges and disks with cutting blades. Rotation of a crank drives the smooth 
roller while the cutting roller is simultaneously driven by a gearing 
meachanism positioned at one end of both rollers. Two metal shelves are 
placed to receive and support the meat as it is run horizontally through 
the two rollers. 
Finally the chicken steak machine taught by Wood in U.S. Pat. No. 1,991,439 
involves the use of two rollers (one of which is free-wheeling) with 
circumferential rows of teeth interspaced by grooves. A roller adjusting 
device includes cam plates which allow for the adjustment of the relative 
roller positions in accordance with meat thickness. Tough meat is fed 
horizontally between the rollers as a crank is turned. 
SUMMARY AND OBJECTS OF THE INVENTION 
The invention concerns a meat tenderizing mechanism enclosed by a housing 
base and safety cover, wherein the base is secured to the cover by spring 
loaded knobs. The safety cover has a slot through which a piece of meat is 
fed and vertical feed guides which direct the meat to two roller 
assemblies. Each roller assembly includes an axle with a square 
cross-section, an alternating series of bladed disks and spacers mounted 
along the axle, a gear at one end of each disk-spacer series and all is 
secured by roller bearings on both ends of the assemblies. 
The roller assemblies are slipped into spaced housing base slots such that 
the roller bearings are in rotatable contact with the housing base and the 
gears of the roller assemblies mesh. A crank handle, which can be utilized 
for left or right handed operation, is attached to one extended roller 
assembly axle. Rotation of the crank handle directly drives the roller 
assembly to which the handle is attached and drives the other assembly via 
the meshed gears. 
The four rubber suction cups beneath the housing prevent slippage of the 
unit during operation. 
When operating, the roller assemblies draw the meat inward as the bladed 
disks sever the meat tissues, thus tenderizing the meat. The two 
stationary teethed stripper plates are provided adjacent to the roller 
assemblies. As the bladed disks rotate, each bladed disk contacts a tooth 
of the stripper plate which strips the slice of meat from the rotating 
bladed disks and at the same time prevents the meat from wrapping around 
the rollers, thus allowing the meat to drop onto the receiving tray. 
Thus, the bladed disks are constantly cleaned during the unit operation to 
insure that further tenderizing of the meat is not inhibited. 
Provided in the lower portion of the housing base below the roller 
assemblies and stripper plates is a horizontal slot in which a receiving 
tray is positioned. The tray extends through and beyond two sides of the 
housing base. Once the meat has passed between the roller assemblies, the 
tenderized meat is received or caught by the tray. The operator then pulls 
the tray from the horizontal slot and removes the tenderized meat from the 
tray. 
An object of the present invention is to provide a meat tenderizing unit 
that is easily assembled and disassembled for sanitary maintenance. 
It is also another object of this invention to provide a meat tenderizing 
unit which is completely washable and can be easily cleaned with a brush 
and dishwashing liquid and then thoroughly rinsed. 
Another object of this invention is to present a meat tenderizing unit that 
is economical to use and also safe and easy to operate. 
A further object of this invention is to realize a meat tenderizing unit 
wherein either left handed or right handed operation is readily available. 
An additional object of this invention is to provide a unit for tenderizing 
meat which may be simply constructed in an inexpensive manner.

DETAILED DESCRIPTION OF THE INVENTION 
In FIG. 1 a view is provided of the invention in its assembled form showing 
the tenderizer unit at 10. The tenderizing unit 10 includes a housing 
comprising a cover 12 and a base 14 which form a substantially sanitary 
enclosure for the tenderizer mechanism (discussed below). Mounted on the 
housing cover 12 are two spring loaded knobs 16 (one not shown) that 
engage recesses or holes 18 in the housing base 14 to secure the cover 12 
in position. 
Meat is fed into the tenderizer unit 10 via a cover slot 20 at the top of 
the cover 12 as a crank handle 22 is turned, operating the tenderizer 
mechanism contained within the housing. Roller bearings 24 of the 
tenderizer mechanism are connected to allow rotation of roller assemblies 
(not shown) within the housing. The tenderizer mechanism and roller 
assemblies are discussed in greater detail with respect to FIGS. 2, 3, and 
4. 
A horizontal slot 26 in the lower portion of two sides of the base 14 is 
designed to receive and support a removable tray 28. Once the meat passes 
through the tenderizing mechanism the meat is dropped onto the receiving 
tray 28 which is drawn outward for easy access to the meat by the 
operator. Rubber suction cups or feet 30 are attached to the bottom of the 
base 14 and are utilized to hold the tenderizer unit stable when operated. 
FIG. 2 shows a cut away view of the tenderizing unit 10 of FIG. 1. Meat 
entering the unit 10 at cover slot 20 is guided to the tenderizing 
mechanism by vertical feed guides 32. The feed guides 32 prevent the meat 
from being misdirected within the unit 10 which may result in the 
tenderizing mechanism being jammed. The meat then encounters two roller 
assemblies of the tenderizing mechanism which comprise the means for 
tenderizing the slice of meat. 
Each roller assembly includes an axle 34, 36 having a square cross-section 
on which an alternating series of spacers 38 and bladed disks 40 are 
mounted. The spacers 38 and bladed disks 40 have square holes at their 
centers for appropriate mating with the axles 34, 36. The series of 
spacers 38 and bladed disks 40 of axle 34 are shifted with respect to the 
series of axle 36 such that a bladed disk 40 of one axle is opposite a 
spacer 38 of the other axle. 
Each bladed disk 40 is provided with a multiplicity of cutting edges 42, 
that engage the surface of the meat, severing its tissues as the 
tenderizer mechanism is operated. The axles 34, 36 are positioned and the 
bladed disks 40 dimensioned such that the bladed disks 40 of one axle (34, 
for instance) overlap the bladed disks 40 of the other axle (36). Rotation 
of crank handle 22 (See FIG. 1) causes the left axle 34 to rotate 
clockwise while the right axle 36 rotates counterclockwise, drawing the 
meat between the roller assemblies. 
Immediately below the roller assembly on the left axle 34 is a stripper 
plate 44 secured to the inside of the base 14 via supports 46. The 
stripper plate 44 and supports 46 may be better observed in FIG. 3 and are 
discussed in greater detail below. Immediately below the roller assembly 
on the right axle is a stripper plate 45 secured to the base 14 via 
supports 46. As is evident from FIG. 2, receiving tray 28 is positioned 
beneath the roller assemblies to catch the tenderized meat. The receiving 
tray 28 is then pulled to the left or right (as viewed in FIG. 2) from the 
horizontal slot 26 for removal of the meat from the tenderizing unit 10. 
FIG. 3 shows a sectional view of the invention along the axle 34 from which 
the details of the tenderizing mechansim (crank handle 22, roller 
assemblies, stripper plate 44 and supports 46) are readily apparent. The 
crank handle 22 is provided with a square hole 48 and is mated with the 
axle 34. A thumb screw 50 is turned into a threaded hole at the end of 
axle 34 securing the crank handle 22 in position. 
To the right of the crank handle 22 and at the opposite end of the roller 
assembly is a roller bearing 24, a nylon spool-shaped free-rolling wheel 
through which the axle 34 also passes. A screw secures the roller bearing 
24 in place on the axle 34. The entire roller assembly is suported via 
vertical slots 52 in the base 14 and is a typical arrangement for each end 
of the right roller assembly built around axle 36. 
The axle 34 roller assembly may be positioned with the handle 22 to either 
side of the base 14 as desired for left or right handed operation. Inside 
both of the roller bearings 24 is a gear 54. The roller assembly of axle 
36 (not shown) is also provided with two gears 54 that mesh with the gears 
54 of the axle 34 roller assembly, the axles 34 and 36 being spaced 
appropriately due to the location of the vertical slots 52. 
Similar but shorter slots are provided on the cover 12 which engage the top 
of the roller bearings 24 when the cover 12 is in place. An alternating 
series of bladed disks 40 and spacers 38 then follow the gear 54, the 
series being terminated at the right by a roller bearing 24. Such an 
arrangement is typical of the axle 36 roller assembly, however the 
alternating series begins with a spacer 38 followed by a bladed disk 40. 
Thus, with the roller assemblies in place, a bladed disk 40 of one axle 
rotates opposite a spacer 38 of the second axle, permitting a slight 
overlap of the bladed disks 40. As the axles 34, 36 are rotated, each 
cutting edge 42 revolves through an imaginary vertical plane that 
corresponds to the path the meat travels when passing between the roller 
assemblies. 
The stripper plate 44 with numerous teeth 56 is attached to sides of the 
base 14 and is located just below the roller assembly on axle 34. The 
spacing between the teeth 56 allows a bladed disk 40 sufficient clearance 
to spin, yet is narrow enough to strip or scrape from the bladed disk 40 
the tenderized meat slice and any meat particles which have accumulated 
thereon. With this provision, the bladed disks 40 are freed of meat 
particles which would inhibit additional meat tenderizing. If permitted to 
accumulate, efficient operation of the unit may be substantially impaired. 
The stripper plate 45 located just below the roller assembly on axle 36, as 
shown in FIG. 2, serves the same purpose as stripper plate 44 located just 
below the roller assembly on axle 34. 
FIG. 4 shows a plan view of the invention with cover 12 removed, portraying 
the relationship of two roller assemblies to one another. From this view, 
the interrelationship of the two roller assemblies can be appreciated. The 
four roller bearings 24 at each end of the two axles 34, 36 are positioned 
in the four vertical slots 52. The location of the slots 52 in base 14 
insures a mesh between the gears 54 for correct operation of the 
invention. 
As the crank handle 22 is turned the directly connected roller assembly of 
axle 34 is rotated. The axle 36 roller assembly is driven indirectly via 
the meshed gears 54 in response to turning of the crank handle 22. The 
overlap of the bladed disks 40 is apparent in FIG. 4 and line X--X 
represents the vertical plane through which each cutting edge 42 passes. 
It can also be seen that each bladed disk 40 of one axle rotates adjacent 
to a spacer 38 of the second axle. 
Eight supports are visible which are attached to the stripper plates 44 and 
45 and the base 14 for supporting the stripper plates 44 and 45 in a 
manner that properly positions the teeth 56 (not shown) in FIG. 4 with 
respect to the bladed disks 40. 
The tenderizing unit 10 is easily disassembled for cleaning. To disassemble 
the unit, the receiving tray 28 is drawn from the horizontal slot 26 and 
the cover 12 is removed. The roller assemblies are then lifted from the 
vertical slots 52 revealing the stripper plates 44, 45 and their supports 
46. 
Each roller assembly may then be cleaned by hand with a brush and 
dishwashing liquid. Cleaning of the base 14 interior is also simple with 
the roller assemblies set aside. The safety cover 12 and the receiving 
tray 28 may also be cleaned with a cloth and dishwashing liquid, thus 
maintaining the entire unit in a sanitary condition. 
Other modifications of the tenderizing unit are apparent to one skilled in 
the art which do not depart from the spirit of the invention. 
For instance, the axles 34 and 36 cross-section and hole shape of the 
bladed disks 40 and spacers 38 may be triangular, rectangular, pentagonal, 
etc. A screw or pin may be used to attach the crank handle assembly 22 to 
the axle 34 instead of thumbscrew 50. 
The described embodiments are therefore considered to be only illustrative 
and not restrictive; the scope of the invention being defined by the 
appended claims.