U.S. patent number 3,704,736 [Application Number 05/078,091] was granted by the patent office on 1972-12-05 for food slicing machines.
This patent grant is currently assigned to The Hobart Manufacturing Company. Invention is credited to Clifford Pratley.
United States Patent |
3,704,736 |
Pratley |
December 5, 1972 |
FOOD SLICING MACHINES
Abstract
A slicing machine has a base which supports an inclined rotary
knife driven by a motor and covered by a removable knife guard. A
carriage is supported for reciprocation adjacent the knife and an
adjustable gage plate, and includes a removable inclined tray
member for supporting the articles to be sliced. A first interlock
system prevents removal of the tray member until the gage plate is
set at zero or flush with the knife, and a second interlock system
prevents operation of the motor when the knife guard is removed for
cleaning. A third interlock system assures that the motor will not
operate when the knife guard is being reassembled in the event the
main motor control switch was inadvertently actuated when the knife
guard was removed.
Inventors: |
Pratley; Clifford (London,
EN) |
Assignee: |
The Hobart Manufacturing
Company (Troy, OH)
|
Family
ID: |
22141852 |
Appl.
No.: |
05/078,091 |
Filed: |
October 5, 1970 |
Current U.S.
Class: |
83/397; 83/DIG.1;
83/719; 83/860; 99/537 |
Current CPC
Class: |
B26D
7/24 (20130101); B26D 7/0616 (20130101); B26D
7/22 (20130101); B26D 7/225 (20130101); Y10S
83/01 (20130101); Y10T 83/96 (20150401); Y10T
83/6518 (20150401); Y10T 83/606 (20150401) |
Current International
Class: |
B26D
7/06 (20060101); B26D 7/00 (20060101); B26D
7/22 (20060101); B26D 7/24 (20060101); B26d
004/00 () |
Field of
Search: |
;146/12R,12H,12C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Abercrombie; Willie G.
Claims
What is claimed is:
1. In a slicing machine including a base supporting a carriage for
reciprocating movement adjacent a rotatable slicing knife driven by
a motor, a gage plate supported for adjustment relative to said
carriage and the cutting edge of said knife, and said carriage
including a removable tray member for supporting articles to be
sliced, the improvement comprising an interlock mechanism operable
to permit removal of said tray member only when said gage plate is
locked in a position substantially flush with said knife and
protecting the cutting edge of said knife.
2. A slicing machine as defined in claim 1 wherein said interlock
mechanism effectively connects retaining means for said tray member
with adjusting means for said gage plate.
3. A slicing machine as defined in claim 2 wherein said interlock
mechanism is operable only when said carriage is positioned at one
end of its stroke of reciprocating movement.
4. A slicing machine as defined in claim 1 wherein said interlock
mechanism is effective to prevent adjustment of said gage plate
when said tray member is removed.
5. A slicing machine as defined in claim 1 including a removable
guard member disposed in a covering position adjacent at least a
part of said knife, and a second interlock mechanism operable to
permit energizing of said motor only when said guard member is
located in said covering position.
6. A slicing machine as defined in claim 4 wherein said knife is
supported by a tubular shaft, said guard member is supported by a
rod extending into said shaft, means for locking said rod within
said shaft, a switch connected to control said motor, and means for
actuating said switch in response to actuation of said locking
means only when said rod is secured correctly within said
shaft.
7. A slicing machine as defined in claim 4 including a main control
switch for said motor, and a third interlock mechanism effective to
prevent operation of said motor when said guard member is being
reassembled after said main control switch is inadvertently
actuated to a position for energizing said motor.
Description
BACKGROUND OF THE INVENTION
In a food slicing machine as disclosed in U.S. Pat. No. 3,051,207
and in British Pat. No. 955,343, which issued to the assignee of
the present invention, it is common to mount the inclined food
support tray on the reciprocating carriage so that it can be
conveniently removed to facilitate cleaning of the tray as well as
cleaning of the adjustable gage plate and the knife. It is also
common to provide for removing the guard plate which partially
covers the knife to simplify cleaning of the knife.
It has been found desirable to prevent removal of the carriage tray
member unless the adjustable gage plate is positioned at its zero
setting or flush with the cutting edge of the knife. This assures
that the exposed portion of the sharp cutting edge of the knife is
guarded or protected when the tray member is removed and thereby
reduces the possibility of the operator's hand inadvertently
slipping and engaging the sharp cutting edge of the knife. It has
also been found desirable to prevent operation of the drive motor
for the knife when the guard plate covering the knife is removed
for cleaning purposes. Furthermore, when the knife guard plate is
removed, it is desirable to assure that the knife will not begin
rotating while the guard plate is being replaced in case the main
control switch for the motor was inadvertently actuated while the
knife guard is removed.
SUMMARY OF THE INVENTION
The present invention is directed to an improved food slicing
machine of the type generally described in the above patents and
which incorporates interlock systems to prevent removal of the
carriage tray except when the gage plate is at its zero setting
flush with the knife and/or to prevent operation of the motor
driving the knife when the knife guard is removed or is being
reassembled.
In accordance with a preferred embodiment of the invention, the
carriage tray is secured to the carriage support arm by a mechanism
which can be operated only when the carriage is in its forward
position and the gage plate is at its zero setting. The knife guard
is mounted on an elongated rod which extends through a tubular
drive shaft for the knife and is retained by a lock pin extending
from a knob. When the lock pin properly engages the support rod of
the knife guard to lock the guard in place, a normally open switch
in series with the knife drive motor is closed. When the knife
guard is removed, the switch remains open so that the motor cannot
be energized.
The control circuit for the motor includes a main motor control
switch and also a holding circuit consisting of a relay which is
actuated by another interlock switch adapted to be momentarily
closed when the main control switch is closed. This control system
assures that the motor cannot be energized until after the knife
guard is replaced and secured and then the main control switch is
actuated.
Other features and advantages of the invention will be apparent
from the following description, the accompanying drawings and the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a food slicing machine constructed
in accordance with the invention;
FIG. 2 is a fragmentary perspective view of the machine shown in
FIG. 1 and with some of the components exploded and with other
components shown in phantom to show internal construction;
FIG. 3 is a fragmentary section taken generally on the line 3--3 of
FIG. 1;
FIG. 4 is a fragmentary section taken generally on the line 4--4 of
FIG. 3;
FIG. 5 is a fragmentary section taken generally on the line 5--5 of
FIG. 8;
FIG. 6 is another fragmentary section taken generally on the line
6--6 of FIG. 8;
FIG. 7 is a schematic electrical wiring diagram for the
machine;
FIG. 8 is a fragmentary section taken generally on the line 8--8 of
FIG. 10;
FIG. 9 is a fragmentary perspective view of a portion of the
interlock mechanism shown in FIG. 2;
FIG. 10 is a fragmentary elevational view of the machine and with
portions broken away to show internal construction; and
FIG. 11 is a fragmentary plan view of the control mechanism for
operating the knife drive motor.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The slicing machine shown in FIG. 1 generally includes a housing 15
forming a base with an upwardly projecting hollow portion 16 at one
corner, an elongated upwardly projecting hollow portion 18 along
one side and a horizontal platform surface 20. Referring to FIG. 3,
an electric motor 25 is mounted within the housing portion 16 and
includes an output shaft on which is mounted a worm gear 26. An
inclined tubular shaft 28 is rotatably supported within the housing
portion 16 by a set of anti-friction bearings 29 and has an upper
end portion 31 having external threads. A gear 33 is mounted on the
lower end portion of the tubular shaft 28 and engages the worm gear
26 so that the shaft 28 is driven by the motor 25.
A circular slicing knife 35 having a sharp outer peripheral cutting
edge 36, is mounted on the upper end portion 31 of the shaft 28 and
is secured to a plastic sealing ring 38 which is threaded on the
shaft portion 31 and has a circumferential lip which engages an
annular curved surface 39 on the upper end of the housing portion
16 to form a rotary seal between the knife 35 and the housing
portion 16. A formed sheet metal knife guard 45 covers a
substantial portion of the knife 35 and is mounted on the upper end
portion of a support rod 46 which extends through the tubular shaft
28. A V-shaped notch 48 is formed within the lower end portion of
the support rod 46 and is engaged by the inner pointed tip of a
rotatable lock pin 51 extending from a knob 52.
As shown in FIGS. 3 and 4, the lock pin 51 is threaded into a
sleeve 54 which carries an inwardly projecting pin 56 (FIG. 4)
adapted to actuate a normally open interlock switch 58 when the
sleeve 54 moves inwardly on the lock pin 51. A compression spring
59 is mounted on the lock pin 51 and urges the sleeve 54 against an
annular shoulder or surface 61 surrounding the lock pin 51. When
the lock pin 51 is retracted or unthreaded, the knife guard 45 and
its supporting rod 46 may be removed to facilitate cleaning of the
guard and the knife 35. While the rod 46 is removed, if the knob 52
is rotated, the lock pin 51 threads itself into the sleeve 54 until
the knob bottoms on the housing. The sleeve 54 remains adjacent the
shoulder 61 so that the pin 56 holds the normally closed switch 58
in an open position.
When the knife guard 45 and supporting rod 46 are reassembled to
the position shown in FIG. 3, and the knob 52 is rotated, the lock
pin 51 threads downwardly within the sleeve 54 until the pointed
tip of the pin engages the notch 48 within the rod 46. After this
engagement, further rotation of the knob 52 causes the sleeve 54 to
move upwardly away from the shoulder 61 thereby retracting the pin
56 from the switch 58 causing the switch to return to its normally
closed position. As shown in FIG. 7, the switch 58 is connected in
series with the motor 25 so that the motor cannot be energized
unless the switch 58 is closed.
Referring to FIGS. 1 and 2, a generally flat gage plate 65 is
supported on an angle parallel with the knife 35 by a pair of
parallel spaced inclined rods 66 (FIG. 2) which are slidably
received within corresponding bores formed within the housing
portion 18. A pin 68 projects outwardly from the rear guide rod 66
and is received within a slot formed within an end portion of a
lever 70 pivotally mounted on cross pin 72. The lever 70 includes a
portion which extends between adjacent flights of a worm 74 mounted
on a shaft 76 rotatably supported by the housing portion 18. A knob
78 is mounted on the outer end portion of the shaft 76 adjacent the
front wall of the housing 15 and provides for rotating the worm 74
to effect pivoting of the lever 70 and corresponding sliding
movement of the gage plate 65. A graduated scale 79 is formed on
the knob 78 to indicate the position of the gage plate 65 within
its range of movement between a zero setting where the upper
surface of the gage plate 65 is flush with the upper surface of the
knife 35 and an open position where the gage plate is positioned a
fraction of an inch below the cutting edge of the knife 35
according to the desired thickness of the slices to be
produced.
A pair of parallel spaced guide rods 84 (FIGS. 8 and 10) extend
longitudinally within the upwardly projecting hollow portion 18 of
the housing 15 and slidably support a carriage 85 which includes a
vertical hollow arm 86 mounted on a generally horizontal arm 88
slidable on the lower guide rod 84. A lever 89 is rigidly secured
to the arm 88 and has a bifurcated upper end portion which receives
the guide rod 84 between opposing low friction plastic studs
91.
A pair of angularly disposed surfaces 94 (FIG. 6) are formed on the
upper end of the carriage arm 86 and slope downwardly parallel to
the axis of the knife supporting shaft 28 on opposite sides of a
slot 96. The carriage 85 includes an L-shaped tray member 100
having angularly arranged walls 102 and 103 each of which also
slopes downwardly parallel to the axis of the knife shaft 28. A
wedge block 105 (FIGS. 2 and 6) is secured to the underneath
surface of the wall 103 and seats on the surfaces 94 on the upper
end of the carriage arm 86. The wedge block 105 includes a
downwardly projecting end portion 107 (FIG. 2) on which is mounted
a downwardly extending tongue-like locking plate 108 having a cam
slot 109.
When the tray member 100 is mounted on the carriage arm 86, the
locking plate 108 is adapted to slide within the slot 96 below a
rotatable locking pin or bolt 110 (FIG. 6) extending through the
upper end portion of the carriage arm 86 and having an angularly
extending handle 112. A forked or V-shaped slot 115 (FIG. 6) is
formed within the locking bolt 110 and receives the inner end of a
retaining screw 116 which enables the bolt 110 to be rotated
through a predetermined angle as well as move axially within the
bore which receives the bolt. A recess 118 (FIG. 2) is formed
within the locking bolt 110 for receiving the plate 108, and a pin
120 projects outwardly from the locking bolt 110.
A compression spring 122 urges the locking bolt 110 axially to the
right as shown in FIG. 6. After the tray member 100 is seated on
surfaces 94 of the carriage arm 86, and the plate 108 extends
within the recess 118 of the locking bolt 110, the locking bolt is
rotated with the aid of the handle 112 so that the bolt presses
downwardly on the plate 108 to effect clamping of the tray member
100 to the carriage arm 86. When the lock bolt 110 is rotated, the
pin 120 engages the cam slot 109 causing the lock bolt 110 to move
axially within the upper end portion of the carriage arm 86,
compressing the spring 122.
When the lock bolt 110 is cammed inwardly, a hole 123 formed within
the lock pin 110 is aligned to receive the upper end portion of a
locking rod 124 (FIG. 2) which is urged upwardly within the
carriage arm 86 by a compression spring 125. The lower end of the
locking rod 124 is connected to the outer end of a pivot lever 126
(FIG. 5) mounted on the lower arm 88 of the carriage 85. The inner
end of the pivot lever 126 is connected by a link rod 128 to a
rocking plate 130 (FIG. 2) pivotally supported by a pin 132. A set
of spaced tabs 134 and 136 project upwardly from the rocking plate
130 and are adapted to receive a rectangular extension portion 138
of the lever 70 which projects between the adjacent flights of the
worm 74.
In normal use of the slicing machine, the tray member 100 is
mounted on the upper end of the carriage arm 86, and the locking
bolt 110 is rotated to its locked position where it is retained by
the upper end portion of the locking rod 124 which projects into
the hole 123. When it is desired to remove the tray member 110, the
knob 78 is turned to its zero setting indicating that the gage
plate 65 is flush with the cutting edge 36 of the knife 35.
Rotation of the knob 78 causes the lever 70 to move to the position
shown in FIG. 2 so that when the carriage 85 is moved to the
forward limit of its stroke (FIG. 2), the inner edge of the lever
70 engages the inner tab 136 of the rocking plate 130 causing the
rocking plate to pivot.
The pivoting of the rocking plate 130 moves the inner link rod 128
upwardly and the outer locking rod 124 downwardly to retract the
upper end portion of the locking rod from the hole 123 within the
locking bolt 110. This enables the locking bolt 110 to be rotated
approximately 110.degree. for releasing the plate 108 projecting
from the mounting block 105 of the tray member. When the rocking
plate 130 pivots in response to engagement between the lever
portion 138 and the tab 136, the forward tab 134 moves upwardly to
engage the forward end of the lever portion 138. As a result, when
the locking rod 124 is retracted from the locking bolt 110, the
rocking plate 130 prevents rotation of the worm 74 and the knob 78
so that the gage plate must remain at its zero setting and the
carriage must remain at the forward limit of its stroke as long as
the tray member 100 is removed.
If the locking bolt 110 is rotated while the carriage tray 100 is
removed, the locking bolt 110 will not move axially since there is
no cam surface for the pin 120 to engage. Thus the hole 123 does
not move into alignment with the locking rod 124, thereby
preventing pivoting of the rocking plate 130 or rotation of the
knob 78. As shown in FIGS. 1 and 2, the tray member 100 includes a
curved guard plate 140 which projects upwardly from the forward
wall 102 to help cover the knife 35 when the carriage is moved
rearwardly. The tray member also supports a gripper 142 which is
mounted on an arm 143 slidably supported by a guide rod 144. The
gripper 142 carries a clear plastic shield 145.
Referring to FIGS. 7 and 11, a main control switch 146 is located
within the base of the housing 15 and is connected in series with
the motor 25 which is adapted to receive power from supply lines
L.sub.1 and L.sub.2. The switch 146 includes a toggle actuator 147
which is positioned between a pair of spaced collars 148 mounted on
the inner end portion of an actuating rod 150 extending
longitudinally within the base portion of the housing 115. A knob
152 is secured to the outer end portion of the actuating rod 150
and is located outboard of the front wall of the housing 15 as
shown in FIGS. 1 and 2.
A collar 154 is slidably mounted on the rod 150 and is urged
against the toggle actuator 147 of the switch 146 by a compression
spring 155. A normally open switch 158 is positioned adjacent the
main control switch 145 and is connected in series with the switch
58 and the motor 25 as shown in FIG. 7. A relay coil 160 is
connected in parallel with the motor 25 and includes normally open
contacts 162 which are connected in parallel with the switch
158.
When it is desired to start the motor 25 of the slicing machine,
the knob 152 is pulled outwardly to effect closing of the switch
146. Continued pulling of the knob 152 causes the spring 155 to
compress and the forward collar 148 to actuate the switch 158.
Momentary closing of the switch 158 is effective to energize the
relay coil 160 which closes the contacts 162 thereby holding the
circuit closed so that the motor 25 remains energized. When the
knob 152 is released, the actuating rod 150 returns to its normal
position due to the force of the compression spring 155, and the
switch 158 opens.
The function of the electrical control circuit shown in FIG. 7 is
to assure that the motor 25 will not be energized while the knife
guard 45 is being replaced and switch 58 is closed in response to
tightening of the knob 52. That is, if the start control knob 152
is inadvertently pulled outwardly while the knife guard 45 is
removed during cleaning, switch 146 will close. However, when the
knife guard 45 is being remounted on the slicing machine, the motor
25 will not be energized when the switch 58 closes since the switch
158 and the relay contacts 162 will both remain open until the
start control knob 152 is intentionally pulled outwardly against
the bias of the spring 155 to effect momentary closing of the
switch 158.
From the drawings and the above description, it is apparent that a
slicing machine constructed in accordance with the invention
provides desirable features and advantages. For example, the
mechanism carried within the carriage arms 86 and 88 for securing
and locking the carriage tray member 100, cooperates with the gage
plate actuating lever 70 to provide an interlock system which
prevents removing of the carriage tray member 100 until the gage
plate 65 is set at zero and the carriage 85 is moved to the forward
limit of its stroke. Furthermore, as long as the tray member 100 is
removed from the carriage support arm 86, the interlock mechanism
prevents rotation of the knob 78 and corresponding movement of the
gage plate 65 and also prevents movement of the carriage 85. As a
result, at all times while the tray member 100 is removed from the
carriage support arm 86, the forward exposed portion of the cutting
edge 36 of the knife 35 is guarded by the rearward portion of the
gage plate 65. Thus if the hand of the operator accidentally slips
while he is cleaning the slicing machine, the chances of the
operator's hand engaging the exposed portion of the cutting edge 36
are substantially reduced.
Another important feature provided by the slicing machine of the
invention is the interlock system described in reference to the
mechanism shown in FIG. 3. That is, when the knife guard 45 is
removed from the machine to facilitate cleaning of the knife 35,
the switch 58 opens and remains open so that the motor 25 cannot be
energized. Closing of the switch 58 can only be accomplished by
inserting the knife guard support rod 46 into the tubular knife
support shaft 28 as shown in FIG. 3, and then rotating the knob 52
until the pin 51 locks the support rod 46 in position after which
the switch 58 is actuated by the upward movement of the sleeve 54
and the pin 56. As mentioned above, a third interlock system is
provided by the electrical control circuit shown in FIG. 7 which
assures that the motor 25 cannot be energized unless the start
control rod or button 152 is intentionally pulled out against the
bias of the compression spring 155.
While the form of apparatus herein described constitutes a
preferred embodiment of the invention, it is to be understood that
the invention is not limited to this precise form of apparatus, and
that changes may be made therein without departing from the scope
of the invention which is defined in the appended claims.
* * * * *