Pressure Cooking Apparatus

Abstract

Apparatus for the pressure frying of chicken and other foodstuffs in oil or shortening which includes a support base, an open topped pot for holding frying oil that is mounted on the base and which has a horizontal flange surrounding the top thereof, a cover for the pot and means for heating the pot. There are hydraulic cylinder means mounted at each side of the pot, and the cover is carried on the hydraulic cylinder means for vertical movement relative to the pot. A plurality of locking pins are mounted vertically in the flange, each of the pins having a shank and an enlarged head above the shank. The cover has vertical holes in its edges which are axially aligned with and correspond in number to the locking pins and are of a size adapted to receive the pins when the lid is in a closed position adjacent the flange. The pins are of such length that when the lid is in closed position the heads and at least a part of the shank portions of the pins project through and extend upwardly beyond the holes in the cover on the upper side thereof. Cover locking means are mounted on the top side of the cover and comprise at least one slidable locking plate having slots corresponding in number and location to the locking pins. Each of the slots is keyhole shaped with the enlarged ends all arranged in the same direction. Means are provided for moving the locking plate between a first, unlocked position with the enlarged ends of the slots aligned with the pins and a second, locked position with the narrower ends of the slots aligned with the locking pins. When the cover is closed and the locking plate is in locking position, the narrower parts of the plate embrace the shanks of the pins to hold the cover tightly closed. The apparatus includes a hydraulic system for actuating the cover lifting cylinders and the locking plate and electrical circuitry for automatically cycling the apparatus to repeatedly cook measured batches of chicken or other food.

Description

BACKGROUND OF THE INVENTION

A phenomenon of recent years has been the very rapid increase of specialty stores offering prepared foods for sale. Some of the earliest of the specialty stores were those which prepared and sold fried chicken. Today the preparation fried chicken for "on the premises" or "take home" consumption is a multimillion dollar business. In order to prepare fried chicken in a quick and efficient manner the use of pressure vessels has become widespread. Hopefully the operation should be automated as much as possible. The instant invention is directed to a new and novel apparatus for pressure frying chicken which is safe, fast and efficient.

THE PRIOR ART

In the main, the chicken fryers used heretofore are little more than oversized home pressure cookers, such as those sold under the trademarks "Presto" and "Mirromatic" which are almost entirely manually operated. That is, when when the frying is finished, the pressure is released and the cover is manually raised or lifted off and the chicken pieces are manually removed from oil or shortening in the pot. This is both cumbersome and time-consuming.

It is an object of this invention to provide a semiautomated food frying apparatus which is safe and efficient and can be easily operated.

It is another object of the instant invention to provide a large pressure frying apparatus which comprises a system whereby the cooking oil or fat is rapidly removed from the cooking vessel after a cooking cycle, thereby reducing the shortening residue on the cooked food, facilitating the filtering of the oil or fat and its reintroduction to the cooking vessel.

It is another important object of the instant invention to provide an automatically cycled pressure frying apparatus which is designed to accept a plurality of standard grid racks or trays which are widely used in the restaurant and food service fields so that the food to be fried, for example chicken parts, can be assembled on the trays, inserted into the cooking vessel, supported therein beneath the surface of the cooking oil or fat, removed from the vessel and carried on the same racks or trays so as to improve the the exposure of the food to the heated oil or fat and minimize the number of times the pieces must be handled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view in elevation of an apparatus embodying the invention with parts broken away and parts shown in phantom;

FIG. 2 is a side view in elevation of the apparatus shown in FIG. 1 taken from the left side of FIG. 1, with parts shown in phantom;

FIG. 3 is a top view of the apparatus shown in FIG. 1 with some parts shown in phantom;

FIG. 4 is a vertical-sectional view taken along the line 4-4 of FIG. 3;

FIG. 5 is a horizontal sectional view taken along the line 5-5 of FIG. 1;

FIG. 6 is a fragmentary side view with parts broken away showing the cover locked in place on the cooking pot of the apparatus of the invention and shown on an enlarged scale;

FIG. 7 is a further enlarged fragmentary view with portions broken away of a filter tank and muffler useable with an apparatus of the invention;

G FIG. 8 is an enlarged, fragmentary, vertical sectional view along the line 8-8 of FIG. 1;

FIG. 9 is a further enlarged fragmentary view with parts broken away and parts in cross section taken along the line 9-9 of FIG. 8, showing the relationship of the cover, the pot, and the hydraulic cylinder means when the cover is in closed position;

FIG. 10 is a schematic view illustrating the valving of the cooking medium, such as oil, fat or shortening;

FIG. 11 is a schematic electrical circuit diagram illustrating a control means for the apparatus of the invention;

FIG. 12 is a diagrammatic view partly in perspective illustrating the hydraulic system of an apparatus embodying the invention;

FIGS. 13-15, inclusive are schematic flow diagrams which illustrate the positions of the control valves for the shortening during various parts of the cooking cycle;

FIG. 16 is a fragmentary, detailed perspective view of a connecting handle used to actuate the shortening control valves in tandem; and

FIG. 17 is an enlarged view with parts broken away of the rack and supporting means forming a part of the apparatus of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

While the apparatus of this invention can be used to fry almost any kind of food, it is particularly useful in frying chicken cut in pieces, and thus will be described in that connection.

In a preferred embodiment, as seen in FIGS. 1, 2, 3 and 4, the apparatus of the invention comprises a metal frame 20 surrounded by a rectangular cabinet 21 comprising a front wall 22, a back wall 23, and two sidewalls 24. A flue 25 is mounted to and extends up to the back wall 23. The flue 25 communicates with the interior of the cabinet 21. The front wall 22 has a door 26 mounted thereon opening into the interior of the cabinet 21. The frame 20 and cabinet 21 is supported by legs 27, one depending from the frame 20 at each corner. Mounted within the cabinet 21 and resting on the frame 20 is an open topped, rectangular pot 28 which has flutes 29 formed on the underside of the bottom. The pot 28 has a horizontal flange 30 surrounding the top thereof (see FIGS. 4 and 5). The pot 28 also has an outwardly extending flange 31 around the exterior of its midsection. A heat shield 32 is mounted on the flange 30 and depends downwardly therefrom, surrounding the pot 28.

A gas burner 33 is mounted underneath the pot 28 and within the cabinet 21. The burner 33 is connected to a manifold 34 which is in turn connected to a gas supply line 35. A thermostatic unit 36 is located in the bottom of the pot 28 with the conventional temperature adjusting dial 37 which is mounted on the unit 36 inside of the door 26 (FIG. 5). The unit 36 is connected by means of wiring 38 (FIG. 10) to a solenoid 38a which actuates a valve 39 mounted in the gas supply line 35, shutting off the flow of gas once the pot 28 has reached a predetermined temperature. The dial 37 is used to adjust the temperature at which the valve 39 becomes actuated. A thermal limit switch 39a is mounted in the wall of the pot 28 and tied into the electrical system. Gas coming from the supply line 35 passes through the valve 39, then through the manifold 34 and into the burner 33.

An oil or shortening inlet 40 is formed in the side of the pot 28 and a drain outlet 41 is provided in the bottom.

Angle brackets 42 are welded or otherwise secured on each side of the cabinet 21. Each angle bracket 42 is bored to accept the lower end of one of a pair of tubular piston rods 43 of hydraulic cylinders 44 or 45 which are vertically mounted thereby and extend upwardly parallel to each other. The hydraulic cylinders 44 and 45 are identical. As seen in FIGS. 8 and 9, each of the hydraulic cylinders 44 or 45 comprises a tubular cylinder 46 which is closed off at its upper end by an end cap 47 comprising a base 48 and a depending skirt 49 that is threaded onto the upper end of the tubular cylinder 46. An orifice 50 is bored at the center of the base 48.

An O-ring 51 is located in the top surface of the base 48 of the cap 47 circumjacent the orifice 50 and an O-ring 52 is recessed in the inside surface of the skirt 49 of the cap, respectively to seal these parts. A piston 53 is threaded on the upper end of a tubular body 54 of the piston rod 43 within the cylinder 46. The piston 53 closes the upper end of the tubular body 54 which is concentric with the cylinder 46, and which has a radial orifice 55 in its wall leading from the interior of the body 54 to an annular space between the body 54 and cylinder 46. The piston rings 56 and 57 seal the piston 53 in the cylinder 46. A center stem 58 extends upwardly from the top surface of the piston 53 and has an O-ring 59 around its periphery. When the hydraulic cylinder 44 is in closed position, the stem 58 extends into the orifice 50 in the end cap 47 and is in sealing relationship therewith (see FIG. 9) . The piston 53 has a central orifice 60 in the stem 58 and a parallel, offset orifice 61 adjacent the stem 58.

The lower end of the cylinder 46 is internally threaded and a gland 62 is screwed therein thus closing off the lower end of the annular space between the cylinder 46 and tubular body 54. The gland 62 has suitable sealing rings 63 and packing 64 on its inner and outer surfaces to seal the gland 62 in place and provide for relative axial movement of the piston rod 43 and cylinder 46.

The lower end of the tubular body 54 of piston rod 43 is closed by an end plug 65 and has a threaded outside portion of reduced diameter which projects through the angle bracket 42. The end plug 65 has a central passageway 66 and two side passageways 67 and 68 all of which lead into the interior of the tubular body 54.

A central tube 69 connects the passageway 66 in the plug 65 to the orifice 60 in the piston 53. Parallel tube 70 connects the passageway 67 to the offset orifice 61 in the piston 53.

The piston rod 43 is secured in the angle bracket 42 by a heavy nut 71 threaded on the reduced diameter portion of the tubular body 54 which projects through the bracket 42. Tightening the nut 71 pulls the shoulder at the reduced diameter of the body 54 against the angle bracket 42 and holds the body 54 in an erect position.

A cover 72 for the pot 28 is mounted on top of the hydraulic cylinders 44 and 45, being bolted or otherwise fixed to the bases 48 of the cylinder end caps 47. The cover 72 is flat and overlies the flange 30 on the pot 28, extending beyond the flange 30 at the sides where the end caps 47 of the cylinders 44 and 45 are attached. Orifices 73 (FIGS. 8 and 9) in the cover 72 are aligned with the orifices 50 in the end caps 47 of the cylinders 44 and 45. A perimeter sealing gasket 74 is mounted on the underside of the cover 72 for engagement with the top of the pot flange 30. One or more pressure regulating valves 75 (FIG. 10) are mounted in the cover 72 to maintain the cooking pressure in the pot 28. A pressure gauge 75a is also mounted on the cover 72. The cover 72 has a plurality of holes 76 in its front and back edges which are axially aligned with and correspond in number to vertical locking pins 77 which are carried in the flange 30 of the pot 28. The pins 77 are of such length that when the cover 72 is in closed position adjacent the flange 30, enlarged heads 78 and at least parts of shank portions 79 of the pins 77 project through the holes 76 beyond the upper side of the cover 72 (see FIG. 4).

Each of the locking pins 77 (FIG. 4) comprises the enlarged head 78, the shank 79, and a body 80 which extends through one of the holes 76 in the cover 72. Each pin 77 has a stem 81 that is threaded into the bottom of its body 80, and which extends through a hole 82 in the pot flange 30 to support an inverted flanged cup 83 on a lower head 84. A spring 85 is compressed to a preset load, between a lip 86 on the lower end of the cup 83 and the bottom surface of the flange 30. If the pressure in the pot 28 rises above the level established by the springs 85, the cover 72 raises, allowing the excess steam to escape between the cover 72 and the flange 30, this assures that the pressure level in the pot never exceeds a safe value.

Two parallel rack supports 87 are attached to the underside of the cover 72 by means of screws 88. Each rack support 87 is formed of a length of heavy wire bent to form a J-shaped support 89, a horizontal rod 90 and a catch 90a near the inner end.

As best seen in FIGS. 1, 4 and 17, tray support rack 91 may be removably engaged in the rack supports 87 to hang into the pot 28 when the cover 72 is in closed position. The rack 91 comprises two end frames 92 having upper ends 92a which are hooked over to engage and slide on the supports 89 and rods 90 of the rack supports 87. Each end frame 92 has three tray support brackets 93 which extend horizontally inwardly and are connected by cross bars 94. Tray stops 95 are vertically attached to the tray support brackets 93 at the back. An open grid, food support tray 96 may be placed on each of the support brackets 93.

In the preferred embodiment the trays 96 are formed as open grids and are of a type which is commonly used in the restaurant and food service field. Thus, food to be fried is placed on the trays 96, the trays 96 assembled on the rack 91 and, when the cover 72 closes, inserted into the cooking pot 28. The food is cooked and then removed from the pot 28 on the same trays and carried to a meal assembling station. At the assembling station the food is removed from the trays 96 and placed into containers for consumer consumption. Thus, only two actual food handling steps are required. The first is to place the food on the trays 96 and the second is to remove the food from the trays 96 and place it into containers.

A slidable locking plate 97 (FIGS. 3, 4 and 6) is mounted on the top of the cover 72 at each side. The locking plate 97 has a plurality of slots 98 corresponding in number to the number of locking pins 77. Each of the slots 98 has an enlarged circular end 99. A smaller guide slot 100 tangentially communicates with the enlarged end 99 of alternate ones of the slots 98 and extends in the opposite direction from the slot 98.

The top surface of the locking plate 97 has an inclined surface 101 straddling each slot 98. Each of the surfaces 101 slope upward toward the smaller end of the slot 98 so that closing force is applied by the locking pins 72 when the plate 97 is in locked position, causing the sealing gasket 74 to be compressed. Small dowels 102 inserted into the cover 72 and projecting through the guide slots 100 serve as a guide means to keep each plate 97 in a straight path as it moves back and forth.

A tube 103 (FIGS. 3 and 9) for carrying hydraulic fluid is connected to the left-hand orifice 73 of the cover 72 by a coupling 104. As previously mentioned the orifice 73 is axially aligned with the orifice 50 in the hydraulic cylinder end cap 47. A T-shaped coupling 105 connects the tube 103 to a tube 106 leading to Port X of a hydraulic cylinder 107 and to a tube 108 that leads to Port X of a second hydraulic cylinder 109, both of which cylinders are mounted on top of the cover 72. Each hydraulic cylinder 107 or 109 contains a conventional piston 110 and rod 111.

Another tube 112 for carrying hydraulic fluid is connected on the opposite side of the cover 72 to the right-hand orifice 73 by a threaded coupling 113. A T-shaped coupling 114 connects the tube 112 to tubes 115 and 116. Tube 115 connects to Port Y of the hydraulic cylinder 107, and tube 116 connects Port y of the hydraulic cylinder 109.

The rod 111 of the hydraulic cylinder 107 is yoked to the plate 97 by a strut 117 and the rod 111 of the hydraulic cylinder 109 is yoked to the plate 97 on the opposite side of the cover 72 by a strut 118.

As best shown in FIG. 3, fluid moving through the tubes 106 and 108 activate the cylinders 107 and 109, moving the plates 97 to the right to an unlocked position with the enlarged ends 99 of the slots 98 aligned with the pins 77 and concentric therewith. Fluid moving through the tubes 115 and 116 into the opposite ends of the cylinders 107 and 109 moves the plates 97 in the opposite direction to a locked position with the far ends of the slots 98 aligned with the locking pins 77. Thus, when the cover 72 is in closed position, the slidable plates 97, in particular the far ends of the slots 98 embrace the shanks 79 of the pins 77, and are held in place by the enlarged heads 78 of the pins 77, thereby tightly locking the cover 72 in place.

As best seen in FIG. 10, oil or shortening is supplied to the pot 28 from a storage tank 119. The oil is first pumped through a pipe 120 by a motor-pump assembly 121. It then passes through a one-way valve 122 into pipe 123, through a three-way valve 124, and then from the three-way valve 124 into pipe 125, through the oil inlet 40, and into the pot 28.

A bypass pipe 126 leading from the valve 124 connects to a second three-way valve 127. The three-way valve 127 is connected to the drain outlet 41 by means of a pipe 128 leading from a coupling 129 attached to the bottom of the pot 28. Another pipe 130 connects the valve 127 to a muffler 131.

The muffler 131 (see FIG. 7) comprises a length of pipe 132 having orifices 133 in its walls and which is connected to pipe 130 by a collar 134 which has similar orifices 135. A cap 136 closes off the lower end of the pipe 132. A conical splash guard 137 depends outward and downwardly from the upper end of the collar 134. Valves 124 and 127 are mechanically connected to operate in tandem by a shaft 138 which has spokelike handles 139.

The two valves 124 and 127 have three positions. These are (1) "Fill," (2) "Cook," and (3) "Drain and Wash" positions. In the Fill position (shown in FIG. 13) the valve 124 connects the oil supply pipe 123 to the upper filling pipe 125 and to the bypass pipe 126. The valve 127 connects the pipe 126 to the bottom pipe 128 which now also serves as a filling line. In the Cook position (FIG. 14) the valves 124 and 127 close off the upper filling pipe 125 and the lower pipe 128 and connect the supply pipe 123 to the tank 119 through the drain pipe 130.

In the Drain and Wash position (FIG. 15) the valve 124 closes the bypass pipe 126 and connects the supply pipe 123 to the pipe 125 and to the pot 28. The valve 127 connects the drain pipe 128 to the pipe 130 and to the tank 119. A heater 140 (FIG. 10) may be mounted in the dump tank if desired.

The movement of the cover 72 relative to the pot 28 and the temperature of the cooking in the pot 28 are temperature the controlled by the electrical and hydraulic systems of the apparatus of the invention shown, respectively, in FIGS. 11 and 12.

The hydraulic system (FIG. 12) comprises a tank 141 which is mounted in the interior of the chicken fryer underneath the burner 33. A motor 142 and a pump 143 connected to the shaft 144 of the motor are mounted on the tank 141. A filter 145 immersed in the fluid is connected to a conduit 146 which in turn is connected to the pump 143. A conduit 147 leads from the pump and divides into two separate conduits 148 and 149. Conduit 148 leads to a double acting valve 150 having Ports A, B, P, and T and is connected to Port P thereof. The valve 150 is actuated by solenoids 151 and 152. The conduit149 leads to a second double acting valve 153 having Ports A, B, P and T, and is connected to Port P thereof. The valve 153 is actuated by solenoids 154 and 155. A conduit 156 connects Port A of the valve 153 with the central orifice 66 of the end cap 65 of the hydraulic cylinder 44.

Another conduit 157 connects Port A of the valve 150 with a conduit 158 which connects with the orifices 67 of the end caps 65 of the hydraulic cylinders 44 and 45.

A conduit 159 leading from the passageways 68 of the hydraulic cylinders 44 and 45 connects with a conduit 160, and this conduit in turn connects with Port B of the valve 150. A conduit 161 connects Port B of the valve 153 with the orifice 66 of the hydraulic cylinder 45.

Conduits 162 and 163 leading from Ports T of valves 153 and 150, respectively, join together forming a conduit 164 which empties into the tank 141.

The electrical circuit of the apparatus of the invention is shown in FIG. 11. Electrical power is supplied by power lines 165 and 166. Three control switches 167, 168 and 169 are connected in parallel between the lines 165 and 166.

The control switch 167 has three positions: "Lock," "Unlock," and "Off." The switch 167 has terminals A, A', B, B', C, C' on one side and D, D', E, E' and F, F' on the other side. The central position is the "Off" position. The control switch 167 is used in part to control the hydraulic valve solenoids 154 and 155 which are electrically connected by the switch 167 to the lines 165 and 166.

The control switch 168 also has three positions: "Lower," "Raise" and "Off," and has terminal terminals A, A', B, B' on one side and terminals C, C' and D, D' on the other side with its central position being the "Off" position.

Control switches 167 and 168 are both used to control the hydraulic valve solenoids 151 and 152, and the pump motor 142, all of which are electrically connected by the switches 167 and 168 to the lines 165 and 166.

The control switch 169 has terminals A and A'. A stepdown transformer 170 the primary 171 of which is electrically connected by the switch 169 to the lines 165 and 166. The secondary transformer coil 172 is loaded by two indicator lamps 173, 174 and the actuating solenoid 38a for the gas valve 39. The temperature limit switch 39a located on the wall of the pot 28 is connected in series in the secondary circuit of the transformer 170 as is the temperature control regulating unit 36.

A control panel 175 carrying the switches 167, 168 and 169 is mounted on the side of the cabinet 21.

If the temperature of the pot 28 is in the safe zone the limit switch 39a contacts will be closed and the indicator lamp 173 will light. If the temperature of the cooking medium, in which the thermostatic control unit 36 is immersed, is at a temperature below the set temperature, the switch in the unit 36 will be closed and the indicator lamp 174 will light. The gas valve solenoid 38a will also be energized causing the valve 39 to open and gas to be supplied to the burner 33. The gas is ignited by a pilot flame (not shown) and raises the temperature of the cooking medium and the pot 28. When the temperature of the cooking medium reaches the set temperature the contacts of the thermostatic unit 36 opens, deenergizing the gas valve solenoid 38a and the lamp 174. Gas flow is stopped and heat is no longer supplied to he cooking pot 28 and medium.

The thermostatic unit 36 will continue to cycle open and closed, maintaining the set temperature within the tolerance of the desired temperature range. When the lamp 173 only is illuminated (and the lamp 174 is out) it indicates that the set temperature has been reached.

To prevent the temperature of the pot 28 from reaching a temperature that would be injurious to it or the cooking medium such as to render it unsafe or unsuitable as a pressure vessel, the temperature limit switch 39a, sensing cooking vessel temperature is, provided. When the maximum safe temperature is reached the switch 39a activates, or opens and the two lamps 173, 174, and the gas valve solenoid 38a are all deenergized, thus removing the heat being supplied to the cooking pot 28.

Holding switch 168 in the "Raise" position closes terminals A to A' and B to B' which energizes the pump motor 142 and solenoid 151. Hydraulic fluid under pressure is caused to flow in Port P and out Port A of valve 150 where it is divided and flows to passageway 67 of hydraulic cylinder 44 and passageway 67 of hydraulic cylinder 45. At the same time, fluid is exhausted from passageway 68 of hydraulic cylinder 44 and passageway 68 of hydraulic cylinder passageway of 45. The exhaust flow from both cylinders 44 and 45 enters Port B of valve 150, leaves Port T of valve 150 and is returned to the tank 141. This action causes the cover 72 to rise until the end of travel of the hydraulic cylinders 44 and 45. Flow from the hydraulic pump 143 will tend to divide evenly to passageways 67 of cylinders 44 and 45 because flow will always favor the lagging cylinder. Releasing switch 168 will cause the switch to return to the center or "Off" position which deenergizes the pump motor 142 and the solenoid 151.

Holding switch 168 in the "Lower" position closes terminals C to C' and D to D' which energizes the pump motor 142 and solenoid 152. Hydraulic fluid under pressure is caused to flow in Port P and out Port B of valve 150 where it is divided and flows to passageways 68 of cylinders 44 and 45. Fluid is exhausted from passageways 67 of cylinders 44 and 45. The exhaust flow from both cylinders 44 and 45 flows in Port A and out Port T of valve 150 and is returned to the tank 141. This action causes the cover 72 to lower until the flange 30 of the cooking pot 28 is reached. Releasing switch 168 causes the switch to return to the center or "Off" position which deenergizes pump motor 142 and solenoid 152.

Holding switch 167 in the "Lock" position closes terminals A to A', B to B' and D to D', which energizes the pump motor 142, solenoid 152 and solenoid 155. Hydraulic fluid under pressure is caused to flow to cylinders 44 and 45 as described in the "Lower" position of switch 168 above. In addition, fluid under pressure flows in Port P and out Port B of valve 153 where it flows through conduit 112 to the Ports Y of cylinders 107 and 109. Fluid is exhausted from cylinders 107 and 109 through the Ports X, and the conduit 103, then flows in Port A and out Port T of valve 153 and is returned to the tank 141. This combined action causes the cover 72 to be forced downward during the locking action. Releasing the switch 167 causes the switch to return to the center position which deenergizes the pump motor 142 and the solenoids 152 and 155.

Holding switch 167 in the "Unlock" position closes terminals D to D D', E to E', and F to F'. The pump motor 142 and solenoid 152 function as described in the "Lock" position above. The solenoid 154 is energized instead of the solenoid 155. Fluid under pressure is caused to flow in Port P and out Port A of valve 153 where it is divided and enters Ports X of cylinders 107 and 109. Fluid is exhausted from Ports Y of cylinder 107 and 109 and then flows in Port B and out Port T of valve 153 to the tank 141. This combined action causes the cover 72 to be forced downward during the unlocking action. Releasing switch 167 allows it to return to "Off" position which deenergizes the motor 142 and the solenoids 154 and 152.

It is apparent from the construction of cylinders 44 and 45 that the above described action of switch 167 will only occur with the cover 72 in the lowered position. With the cover 72 raised or partially raised, holding switch 167 in either the "Lock" or "Unlock" position will cause the cover 72 to lower lower.

Claims

I claim:

1. Apparatus for frying chicken and other foodstuffs comprising in combination: a support frame, an open topped pot for holding frying oil and means for heating said pot mounted on said frame, said pot having a horizontal flange surrounding the top thereof, a plurality of locking pins mounted vertically in said flange, each of said pins having a shank and an enlarged head above said shank, a vertically movable power mechanism mounted adjacent said pot, a cover a said pot carried by said power mechanism for vertical movement relative to said pot, said cover having a plurality of vertical holes in the edges thereof, which are axially aligned with and correspond in number to said locking pins when said cover is in a closed position adjacent said flange, said pins being of such length that when said cover is in closed position at least the heads of said pins project through and extend upwardly beyond the holes in said cover, locking means attached to the top side of said cover and comprising at least one pin engaging member, means for moving said member between a first unlocked position with said member disengaged from said locking pins and a second locked position with said member engaged with said locking pins, and means for energizing said power mechanism, and for moving said pin engaging member.

2. Apparatus according to claim 1 in which said pin engaging member is a sliding plate having slots therein that are engageable with the heads of said pins when in locked position.

3. Apparatus according to claim 2 in which said plate has inclined wedging surfaces adjacent the slots for tightly clamping the cover against the pot flange when said plate is in locked position.

4. Apparatus according to claim 1 and means mounted on the underside of said cover for dependingly supporting trays of food to be cooked.

5. The apparatus of claim 4 wherein the means on the underside of the cover for supporting trays of food comprises two parallel rack supports secured to said cover, a tray support rack removably engageable in said rack supports and having a plurality of parallel horizontal tray support brackets, and an open grid food tray removably supported in each of said tray support brackets.

6. The apparatus of claim 1 wherein said vertically movable power mechanism comprises two parallel vertical hydraulic cylinders, one on each side of the pot, and wherein the means for energizIng said cylinders, and the means for moving said pin engaging member, in selected sequence, are electromechanical.

7. The apparatus of claim 1 wherein said cover and flange are rectangular in outline, said locking pins are arranged in two laterally spaced parallel lines, one line along each of the longer sides of said flange, and wherein the locking means comprises two parallel slidable plates, one on each of the longer sides of said cover, each of said plates having a plurality of slots corresponding in number to the number in the parallel line of pins with which the slots in the plates are aligned.

8. Apparatus according to claim 1 and a supply system for cooking shortening comprising a fill line connected to the pot above the fill level thereof, a drain line connected to the bottom of the pot, a pump and control valves for feeding shortening into said pot through both of said lines and for discharging shortening from said pot through said drain line only.

9. Apparatus according to claim 1 in which said locking pins are mounted in said flange by resilient means resisting upward movement of said pins with predetermined loading.