Lettuce tearing machine

Heads of lettuce are mechanically torn into bite size portions. Each head of lettuce is washed, the outer leaves and core removed, and the cleaned heads are introduced one at a time into a rotating cylindrical basket. The basket upwardly opens and has holes formed in a sidewall thereof of a size to admit torn bite size pieces of lettuce therethrough. The basket rotates about a vertical axis at a speed that engages and tears the heads of lettuce into the bite size pieces. A catching bowl is placed concentrically about the basket and in spaced relationship thereto. The bowl receives the torn lettuce that is thrown through the wall of the rotating basket.

BACKGROUND OF THE INVENTION 
A cafeteria or fast food service will consume a large number of heads of 
lettuce each day. The lettuce is used in salads, and other foods. Lettuce 
is easily cut into fragments that are bite size; however, people do not 
like cut lettuce because it is difficult to manipulate with a fork. 
Therefore, the lettuce, especially when used at a salad bar, must be torn 
into bite size portions. This is time consuming and is also a potential 
source of contamination because the head of lettuce must be intimately 
handled by the person preparing the torn lettuce. It would therefore be 
more sanitary and less costly if the intact or whole head of lettuce could 
be washed, the core and any unwanted outer leaves removed, and then 
mechanically torn into suitable bite size portions. This avoids any 
subsequent, intimate human contact with the cleaned head of lettuce. 
Method and apparatus for achieving this desirable goal is the subject of 
the present invention. 
SUMMARY OF THE INVENTION 
An upwardly opening cylindrical wire basket has openings formed therein of 
a size to produce bite size portions of lettuce when a head of lettuce is 
reduced in size and forced through the openings. This is accomplished by 
judiciously selecting the size of the openings in the basket, the basket 
diameter, and the speed of rotation of the basket. The basket is rotated 
at a sufficiently high speed to create enough centrifugal force to cause 
the interaction between the stationary head of lettuce and the basket to 
effectively tear a head or bunch of lettuce apart as it contacts the 
rotating inner wall surface of the basket and then is forced through the 
bite size openings. The bite size pieces of lettuce are torn from the head 
as a result of the head being forced against the inside surface of the 
wire basket and through the openings as the torn lettuce is thrown into a 
stationary catching bowl. The wire that forms the rotating wire basket 
therefore contacts the stationary head of lettuce and causes the lettuce 
to be torn and not cut. Accordingly, the present invention is a lettuce 
tearing machine as opposed to a cutting machine. 
A primary object of this invention is the provision of a lettuce tearing 
machine which is designed to save millions of man hours in the tedious 
preparation of lettuce which heretofore has been achieved by tearing each 
head or bunch by hand. 
Another object of this invention is the provision of a more sanitary method 
of preparing lettuce wherein after the head of lettuce is rinsed, it is 
put into a spinning basket, where it does not have to be handled by human 
hands. The spinning basket interacts with the head of lettuce in a manner 
that causes the lettuce to be torn into bite sizes and forced through 
openings therein, and into a catching bowl therefor. The basket and bowl 
are easily removed for cleaning purposes. 
These and various other objects and advantages of the invention will become 
readily apparent to those skilled in the art upon reading the following 
detailed description and claims and by referring to the accompanying 
drawings. 
The above objects are attained in accordance with the present invention by 
the provision of a method for use with apparatus fabricated in a manner 
substantially as described herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
In the figures of the drawings, there is disclosed a lettuce tearing 
machine 10 made in accordance with the present invention. The apparatus 10 
includes a base 12 in the form of an enclosed framework which supports an 
annular catching bowl 14. The bowl 14 slidably receives the lower marginal 
end of a conical enclosure 16 therewithin. The conical enclosure upwardly 
extends from the bowl and provides a reduced diameter inlet 18 at the top 
thereof through which ordinary commercially available heads of lettuce 20 
can be tossed. 
A cylindrical stainless steel wire basket 22 is rotatably supported within 
the interior of the enclosure provided by the bowl and conical member 14 
and 16. The wire basket 22 has an open upper end axially aligned with 
inlet 18 through which the heads of lettuce 20 can be introduced about as 
fast as one would care to toss them, which amounts to about one second 
intervals. 
Numeral 24 indicates the interior of the catching bowl 14. The uppermost 
end 26 of the wire basket 22 forms the opening which is opposed to a lower 
plate member 28. The plate member 28 is a circular disk made of stainless 
steel metal to which there is attached the illustrated vertical wires 30. 
The horizontal wires 32 are attached to the vertical wires 30. The wires 
30, 32 form openings 72 which are about two inches long and about 
three-quarters of an inch high. The wires 30, 32 preferably are solid 
one-eighth inch stainless steel members affixed to one another at the many 
intersections thereof. 
The base 12 includes a plurality of support legs 34 which extend from the 
apparatus and preferably are enclosed by the illustrated sheet metal. 
Motor 36 is electrically connected to switch 38, which in turn is 
connected to a suitable source of electrical current. A motor support 
plate 40 is concentrically arranged in parallel relationship respective to 
a bearing support plate 42. The support plates 40, 42 are held in spaced 
relationship by means of radially spaced spreader tubes 44. A drive 
coupling 46 underlies a basket drive 48. The basket drive 48 is located 
above a bearing assembly 50, and the bearing assembly 50 is supported 
within the bearing support plate 42. Motor drive shaft 52 rotatably drives 
the drive coupling 46 which in turn drives a shaft 54 which is connected 
to the basket drive 48. The drive shafts 52, 54 lie along the indicated 
vertical, central, longitudinal axis of the apparatus. 
Latch means 56, 58 can take on any number of different forms so long as it 
enables the basket 22 to be removably received in axially aligned 
relationship respective to the basket drive 48. The latch means preferably 
are a plurality of spaced bonnet headed screws which are received within 
the radially spaced tear drop apertures 58 so that the basket can be 
released and lifted from the upper face of the basket drive 48. 
The catching bowl 14 has an outer vertical wall 60 spaced from an inner 
vertical wall 62, thereby forming an annular lettuce storage chamber 64 
therewithin. Lower skirt 66 of the conical enclosure 16 is slidably 
received within the upstanding wall member 60 of the catching bowl 14. 
As seen in FIG. 3, the upper enclosure member 16 includes an upwardly 
converging conical wall 68 which forms a frustum of a cone. The upper end 
of the wall 68 terminates in a reduced diameter upper skirt member 70 
which forms inlet 18 through which heads of lettuce 20 can be introduced 
one at a time into the enclosure and into the basket. 
The catching bowl 14 is telescopingly received about the wire basket 22 in 
close tolerance relationship with respect to the lower plate member 28. 
The plate member 28 is rotatably positioned at the upper marginal end of 
the inner vertical wall 62 so that the lowermost openings 72 of the wire 
basket 22 are spaced above the upper edge portion of the inner wall 62. 
The bottom or lower wall surface of the catching bowl 14 is provided with 
circumferentially spaced apertures which register with the four bolts 
extending through the tubes 44. The bowl 14 therefore is releasably 
captured and bottom supported by the plate 42 and easily removed 
therefrom. The wire basket 22 is received in axial aligned relationship 
respective to the inner passageway 62 of the catching bowl 14, with the 
annular storage chamber 64 circumferentially extending about the lower end 
of the wire basket 22, so that torn lettuce gravitates into the annular 
chamber 64. The upper conical part 16 of the cover is slidably received 
within the catching bowl and is easily removed therefrom. 
In operation, heads of lettuce are washed, the unwanted leaves and core 
removed, then the heads are dropped through the opening 18 about as fast 
as one desires because less than one second is required for one head of 
the lettuce to be processed by the apparatus 10. 
In one form of the invention, a 1/2 horsepower motor 36 designed to run at 
a speed of 1720 rpm and therefore rotates the basket 22 at 1720 rpm was 
arranged in the manner of the figures of the drawings. The basket was made 
of one-eighth inch wire supported by a 1/4 inch plate member 28, with the 
openings 72 being about 2 inches wide and about 3/4 inches in height. The 
basket has an outside diameter of 81/2 inches and is 8 inches tall. 
The catching bowl 14 has an inside passageway 62 which measures slightly 
more than 81/2 inches in diameter, an outside diameter 60 of 16 inches, 
and was 3 inches in height. The catching bowl 14 was made of stainless 
steel sheet metal and was removably supported by plate member 42 in the 
illustrated manner of FIG. 3. This catching bowl will easily hold five 
heads of lettuce. 
The upper enclosure member 16 was provided with a skirt 66 having an inside 
diameter that is slidably received within skirt member or vertical wall 60 
of bowl 14 and an upper inlet end 70 which is 8 inches inside diameter. 
This is adequate for receiving any head of commercially grown lettuce. The 
overall height of the bowl 14 and enclosure 16 is 14 inches. 
The apparatus was assembled in the manner of FIG. 1. When the motor is 
energized, the wire basket comes up to speed within a second or so. The 
scrubbed heads of lettuce are dropped through the entrance 18 which 
requires a time lapse of about one second between heads of lettuce. This 
is within the capability of the apparatus disclosed herein. The disclosed 
embodiment of the invention will handle five heads of lettuce. After five 
heads of lettuce have been introduced through opening 18, the motor is 
deenergized, the upper enclosure member 16 is removed from the bowl 14, 
the catch bowl 14 is removed from the plate member 42 by telescoping the 
bowl 14 up over the wire basket 22. Most of the torn lettuce is stored 
within annular chamber 64. Some lettuce will cling to the inside 
peripheral wall surface of the upper enclosure member 16 as well as the 
basket 22. This lettuce can be ignored until the last of the lettuce has 
been processed, at which time these few pieces can be gathered and placed 
with the other torn lettuce. 
The bowl 14 is replaced on plate member 42, with the boltheads 45 extending 
through the aligned aperture in the lower face of the bowl. This axially 
aligns the catch bowl 14 with the longitudinal axial centerline of the 
apparatus. The upper enclosure 16 is replaced within the catching bowl 14 
and another five heads of lettuce are processed or torn in the above 
described manner 
FIG. 6 illustrates the inventor's theory of operation. Commercially 
available heads of lettuce 20, such as ordinarily purchased in the 
supermarket, are prepared and then introduced through opening 18 in about 
one second intervals. The heads of lettuce are dropped at 18 and fall by 
gravity to the interior of the rotating wire basket 22. The inner wall 
surface of the rotating wire basket contacts the falling head of lettuce 
and the relative moving surfaces tend to accelerate the head of lettuce, 
while the wire basket 22 is momentarily slightly decreased in speed as 
energy is exchanged between the basket and the head of lettuce. This 
action which takes place between the rotating wire basket and the 
relatively stationary head of lettuce is believed to produce the 
theoretical action hypothetically set forth in FIG. 6. In FIG. 6, the 
horizontal wires 32, which are three-quarters of an inch apart, permit 
torn pieces of lettuce 20' to be forced therethrough. The vertical wires 
30 engage the heads of lettuce with relatively great speed and tear the 
pieces of lettuce 20' from the surface thereof. At the same time, the head 
of lettuce, being contacted on one side by the rotating basket 22, no 
doubt tends to rapidly accelerate in a rotational manner so a new side or 
surface of the lettuce is rotatably brought into intimate contact with the 
rotating wire surface as centrifugal force urges the head of lettuce into 
engagement with the surface presented by the wires 30, 32. Accordingly, 
the head of lettuce is subjected to a very complex number of different 
forces that are brought to act on the head of lettuce from a number of 
different directions, causing the slower moving head of lettuce to 
wipingly engage the inside peripheral surface of the wire basket 22 while 
being forced outward with increased apparent weight due to the centrifugal 
force presented by the basket while at the same time, the wires 30, 32 
embed themselves into the outer surface of the lettuce, thereby pulling 
and tearing bite size pieces from the head of lettuce in the manner 
illustrated in the hypothetical FIG. 6. 
On the other hand, when a head of lettuce is placed into a non-rotating 
wire basket, and then rotated, the operation is entirely unsatisfactory 
and the apparatus vibrates excessively due to the imbalance induced by the 
accelerated head of lettuce. 
Furthermore, a basket speed of 1120 rpm has been found inadequate. The 
preferred speed of 1720 rpm could no doubt be slightly increased or 
decreased. The horsepower could probably be reduced and still carry out 
the present method; however, the time interval between heads of lettuce 
processed may be increased if the power is substantially decreased.