US2966999A - Pressure cooker closure - Google Patents

Description

1961 H. F. swANsoN 2,966,999

PRESSURE COOKER CLOSURE Filed Jan. 5, 1959 2 Sheets-Sheet 1 \\\&

13 INVENTOR. HERBERT F. SWANSON Jan. 3, 1961 Filed Jan. 5, 1959 H. F; SWANSON 2,966,999

PRESSURE COOKER CLOSURE 2 Sheets-Sheet 2 INVENTOR.

AM 6%, WM v ATTORNEY? HERBERT F. SWANSON iii PRESSURE COGKER CLOSURE Herbert F. Swanson, Chicago, Ill., assignor to General Electric Company, a corporation of New York Filed Jan. 5, 1959, Ser. No. 735,077

Claims. (Cl. 220-25) This invention relates generally to cooking apparatus such as pressure cookers, and more particularly to an improved closure and mounting for a pressure cooker.

In pressure cookers provided with a cooking chamber having an opening for the insertion and removal of a product processed within the chamber, the premature opening of the closure at the end of the cooking operation, that is, before the steam pressure within the chamber has been permitted to drop to a low level, may permit the residual steam within the cooking chamber to escape too rapidly, sometimes with injury to the operator. Where the closure opens outwardly, such residual pressure within the vessel may actually be effective to move the closure with what may be explosive force. In the invention herein, the closure is moved inwardly against the pressure within the vessel; and the initial opening movement thereof, which occurs after the release of a latch for the closure, is achieved by a pair of relatively light springs, the bias of which must be greater than the total force against the closure before the closure will disengage from its seat about the chamber opening. The springs cooperate with pivotally mounted support arms for the closure. Said support arms have a lost motion connection with respect to pivot studs projecting from walls of the chamber, whereby upon release of the latch, the springs draw the closure directly rearwardly. After this initial opening movement of the closure is completed, counterbalancing springs complete the pivotal movement of the closurecarrying arms to a position establishing the'closure in a position permitting the removal of pans of the foodstufi or the like which had been processed within the chamber.

It is a general object of this invention to provide an improved closure for a pressure cooker, such closure being so mounted that its initial movement in an opening direction is inward and against the residual pressure within the cooker, such initial movement providing a small annular passage around the closure forthe escape of residual pressure, and being so mounted that upon its further movement it is positioned to one side within the cooking chamber, so that the contents therein can readily be removed.

Another object is to provide an improved closure for a pressure cooker, said closure being removably mounted on a support mechanism which gives to the closure an initial rearward movement from its seat into the cooking chamber, such initial movement beingto an extent .providing a narrow annular passageway for the escape of residual steam, while protecting the operators hand against being scalded; said support mechanism also providing for easy further movement of the closure into the chamber to a fully opened position.

Another object is to provide an improved pressure cooker characterized by a cooking chamber havingran opening and a closure therefor, the closure having a latching structure maintaining the closure in latched position against a closure seat at the opening, the closure moving a slight distance from its seat upon initial operation of the latching structure to provide a passageway through which residual steam in the cooking chamber can escape, the closure amass Patented Jan. 3, 1961 being subsequently movable upon further operation of the latching structure to a position within the chamber where the contents thereof may readily be removed.

Yet another object is to provide a closure for a pressure cooker, said closure being initially movable a small distance into the chamber longitudinally of the opening by reason of a lost motion support for the closure and a spring biasing the closure inwardly, the closure being subsequently pivotable about its support to a fully opened position.

Further features of the invention pertain to the particular arrangement of the elements comprising a closure for the pressure cooker and the support therefor, whereby the above outlined and additional features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which:

Fig. 1 is a perspective view of a pressure cooker embodying the improvements according to the present invention;

Fig. 2 is a vertical section taken through the pressure cooker of Fig. l, substantially along the plane 22 of Fig. 1 and looking in the direction of the arrows, certain parts being shown in elevation;

Fig. 3 is a view similar to Fig. 2, but showing the operation of a latch for the closure of the pressure cooker seen in Fig. 1, showing the latch and closure during their initial operating movement;

Fig. 4 is a view similar to Fig. 3, but showing the closure and the latch in a position where the contents of the pressure'cooker can readily be removed;

Fig. 5 is a horizontal section taken along the line 55 of Fig. 2 looking in the direction of the arrows;

Fig. 6 is an enlarged detailed sectional view of the support for the closure seen in Figs. 2 to 5 inclusive; and

Fig. 7 'is a phantom perspective view showing how the closure is detachably secured to its support arms, so that it can be removed therefrom for cleaning of both the interior of the cooker and its closure.

Referring now particularly to Figs. 1 to 4 of the drawings, the pressure cooker 10 according to the present invention includes a housing li having a base 12 adapted to rest upon feet 13. Opposed side walls 14 of the housing 11 extend from the base 12, and a top 15 extends between the side walls 14.- The housing 11 also comprises a front wall 16 and a rear wall 17 spaced from the front'wall 16.

The housing 11 thus far described encloses a walied pressure vessel 18 including top and bottom walls 19 and 21, side walls 22 and 23 and an end wall 24, defining a cooking chamber 20. In a presently manufactured form, the pressure vessel operates at an internal steam pressure of 15 pounds per square inch, gauge. The front wall 26 of vessel 18 has an opening 27 therein which is aligned with an opening 28 in the front wall 16 of the housing 11. Suitable insulating material 29 is provided between the walls of the vessel 18 and the housing 11, and the vessel 18 is appropriately supported within the housing 11 in spaced relationship thereto by means including the insulating material 29.

Provision is made for heating of the contents within the walled vessel 18, and consists of a heating element 31, preferably of the sheathed resistance conductor type. Heating element 31 is connected by leads 32 to control elements of a control group 33 disposed on the front panel 16. Said control elements provide for theconof electric power.

The opening 27 for the walled vessel 18 has a seat 34 for a closure 36, the closure 36 having the periphery thereof fitted with gasket material 37 of a U-shaped cross section with spaced limbs 38 embracing the closure 36. As seen in the several views, the closure 36 is in the form of a shallow dish, substantially rectangular in shape, with its corners rounded as at 46, see Fig. 7, to correspond to rounded corners 39 of the opening 28 in housing 11.

Structure is provided 'for latching the closure 36 into position firmly against the seat 34 of the vessel 13, and to this end the closure 36 has a U-shaped bracket 41 suitably permanently afiixed to the front side thereof, the spaced limbs 42 of the U-shaped bracket 41 being straddled by a lever '43 pivotally connected by a pin to the U-shaped bracket 41. The lever 43 has its other end provided with a latch member 46 pivotally connected by a pin 47 thereto. The latch member 46 terminates in an operating knob 43, and has a cam-like latching surface 49 cooperating with a pin 51 straddling spaced lugs 52 of a fixed latch abutment 53 secured to the front panel 16 below the opening 28. A stud 53a at the upper portion of abutment 53 is engageable by the wall portion 43a of lever 43 to provide a fulcrum about which lever 43 pivots during opening and closing movements thereof.

As seen in Fig. 2, when the latching surface 49 is engaged with the pin 51, and the latch member 46 is rocked in a clockwise direction, lever 43 will be rocked in a counter-clockwise direction about stud 53a. closure 36 being secured in position against the seat 34 at the end of the latching operation described. The cam shape of the latching element 49 multiplies the mechanical advantage of the latching lever system, reduces the manual effort required to pivot the lever 43 counterclockwise about stud 53a during the latching operation, and improves the control by the operator during the unlatching operation. as later described. Preferably stud 53a is a s rew-threaded p rt, permitting its axial adjustment relative to abutment 53.

Structure is provided fo mo ement of the closure 36 inward of the enin 27 in chamber 26 to a limited degree in a direction normal to t e lon itud al axis of the open n s 27 and 28 noon i itial unl tching mo ement of the latch member 46. Such movement of the closure 36 is inward into the chamber 20 ag inst residual pressure therein. S ch l m ted movement of the c osure 36 provi es an annu ar pas a eway past the seat 34 and around the gas t 37. for the esc pe f residual steam from chamber 20 of the vessel 18. The clos re 36 is mounted for such movement upon a U-shahed c rr er 54, see Fi s. and 7. havin a sh rt ton ue 56 welded thereto at its center. The tongue 56 cooperates w th and extends beneath a clip 55 we ded at 55a to the ins de face of l su e 36. As seen in Fi 7. the closure 36 is thus separ b e from the car ier 54 so that it can be removed for clean n or the l e, as well as the cleaning of the interior of the vessel 18.

The carrier 54 is essentially rigid and extends along the inner side of the closure 36. being bent bevond the periphery thereof. as seen in Fig. 5, to provide a pair of spaced arms 57. Each of the arms 57 is supported on its end remote from t e closure 36 on a stud 58 tapped into a boss 59, see Fig. 6, extending inward from side walls 22 and 23 of the vessel 18.

The arms 57 each have a slot 66 provided therein to give a lost motion connection with the stud 58, and each of the arms 57 is slidably disposed within a guide 61 comprising the spaced plates 63 and 64, plate 63 pivoting at 66 upon the stud 58, and plate 64 pivoting at 67 upon the boss 59. The two plates 63 and 64 are held together at their ends adjacent the boss 59 and the pin 58 by a pair of pins 68, Fig. 3. Similar paired pins 76 hold the plates 63 and 64 together at their other ends. It will be noted that the paired pins 68 and 70 form 4 upper and lower bearings for the arm 57 positioned between the plates 63 and 64.

The carrier 54 is rearwardly biased by a spring 71 at each of the arms 57. Each spring 71 is anchored at one end to its associated arm 57 at a bracket 69 riveted thereto, and at its other end about a grooved seat 72 provided in the stud 58, Fig. 6. Upon initial unlatching movement of the latch 46, the bias of springs 71 will move closure 36 rearwardly when the force exerted against closure 36 by the residual pressure within the chamber is less than one-tenth of a pound per square inch. This inward movement permits the closure to be swung upwardly to the fully open position of Fig. 4 without interference from the top wall of the chamber.

Structure is provided for enabling the closure 36 together with its latch consisting of the lever 43 and the latch member 46 to be moved to a position within the vessel 18 after theresidual steam has been released by the movement of the closure 36 just described. The closure 36 then occupies a position, as seen in Fig. 4, above racks 73 extending between support members 74 extending inward from the side walls 22 and 23 of the vessel 18.

In order to rock the closure 36 to a position seen in Fig. 4, each carrier guide 61 is provided with an ear 76 furnishing a point of anchorage for a spring 77 having its other end anchored to a boss 78 extending inward from the side walls 22 and 23 of the vessel 18. The bias of the spring 77 is such that when the latch 43, 46 has been completely disengaged from the pin 51, see Figs. 3 and 4, the spring 77 will swing the mounting arms 57, 57 about the pins 58, see Fig. 6, moving the closure 36 and latch 43, 46 to the position seen in Fig. 4 above the racks 73.

The outwardly spiraling contour of the latching element 49 permits the closure to move rearwardly of the chamber opening to substantially the maximum extent permitted by the lost motion mounting of the carrier arms 57, before the tip of the latching member has cleared the pin 51. The springs 71 cannot swing the closure upwardly until the disengagement of the latch element from the pin, in view of the upward and rear ward movement of the closure, whereupon the initial opening movement of the closure is essentially horizontally rearward. It will be appreciated that the springs 71 are at maximum tension as the arms 57 assume their horizontal position, and that the forward movement of the arms cannot increase the tension. The angle of effort of the springs 71 relative to the arms in their horizontal position is such that the co-unterbalancing effort of the closure and its carrier, when the closure nears its home position against the opening, substantially overcomes the bias of springs 71, whereas the reduction in the eifective length of arms 57 as the closure attains maximum withdrawn position reduces the overbalancing eifort of the closure and its carrier to render springs 71 capable of initiating the upward swinging movement.

With the parts in the position seen in Fig. 4, the racks 73 can be loaded or unloaded, trays 79 being supported upon the racks 73 within easy reach by the operator, since the closure 36 and its latch 46 are out of the way. It will be noted also that the support for the closure and its latch consisting of the arms 57 are oif to each side of the racks 73, as seen more clearly in Fig. 5.

Assuming foodstuffs to be in the chamber for processing and the closure 36 latched in its sealing position, the operator initiates operation of the cooking apparatus by manipulating appropriate ones of the control group 33, whereupon the heating unit 31 is energized and, after a predetermined interval, water is introduced directly into the chamber through means including a spray head 80, supplied With cold water by way of a conventional solenoid valve 81 connected by conduit 82 to an external water source (not shown). The water impinging on the heated lower wall 21 of the chamber flashes into steam,

the formation of which serves initially to purge the chamber of air through the temporarily opened vent line 83 communicating with the external atmosphere by way of solenoid-operated venting means (not shown), wellknown in the pressure cooker art. After a brief interval calculated to exhaust the air from the chamber, the venting means close and the cooking period commences under control of suitable time-cycle means.

Upon the expiration of the predetermined cooking time, the venting means reopen to permit the steam to escape. It will be obvious that in addition to the locking effort exerted on the closure 36 by the counterclockwise rota-. tion of the latching lever 43 about the pivot stud 53a as the handle 46 comes into its home position, shown in Fig. 2, the steam pressure within the chamber serves also to seat the closure. It will also be obvious that at the end of the cooking operation, it is possible to swing the handle to a substantially horizontal position in which the end of the latching cam member 49 is actually disengaged from the latching pin 51 without the unseating of the closure 36 so long as the steam pressure exerted by the steam against the closure 36 overpowers the biasing effort of the springs '71. It is, of course, not possible for the springs 77 to raise the closure until springs 71 have drawn the closure carrier sufiiciently rearwardly to disengage the closure from the seat 34, whereupon it is evident that the closure can attain its fully open position only after the pressure within the chamber has been reduced to approximately atmospheric level.

From the foregoing description, it is believed evident that there has been provided an improved pressure cooker wherein the closure can be opened a slight amount by initial movement of the latch therefor, the initial movement of the latch providing an annular passageway around the closure to safely complete the venting of residual steam at not toorapid a rate. Where residual steam escapes from the vessel by the initial movement of the closure 36 from its seat, the operators hand at the latch handle 48 is in a position where it cannot be scalded. The further operation of the latch enables the closure 36 to move to a position out of the way of the opening to the housing, and the opening to the vessel supported within the housing, so that the contents within the vessel can be readily removed therefrom.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. In a pressure cooker, a walled vessel defining a cooking chamber, an opening for said vessel including a seat in said opening, a closure for said vessel adapted to engage said seat, latching means maintaining said closure in engagement with said seat, means for carrying said closure including spaced arms extending from said closure, pivot means extending from the walls of said vessel for pivotally supporting said arms relative thereto, a lost motion connection between each of said arms and its pivot means for moving said closure inward of the opening in said chamber and from said seat an initial distance against the residual pressure in said chamber upon initial movement of said latching means in an unlatching direction comprising spring means connected between said spaced arms and the supports therefor and operable to take up the lost motion connection of said arms, said spring means having a bias which is greater than the total force against said closure resulting from the residual pressure in said chamber following a cooking operation, guide means slidably receiving the respective arms, said guide means being rotatably mounted on the said pivot means, and means for moving said closure away from said opening by pivotal movement thereof about said pivot means upon completion of the unlatching movement of said latching means, including spring means connected between said guide means and said walled vessel.

2. In a pressure cooker having structure providing an enclosed food-processing chamber having an end-wall opening afiording access thereinto, the combination comprising a closure for said opening, means for mounting said closure for operation between open and closed positions, said mounting means including structure providing arm members extending along opposite side walls of said chamber, guide means for receiving an end portion of each of said arm members for predetermined movement of said arm members longitudinally of said chamber, means for pivotally mounting said guide means for rotation within said chamber, means for biasing said arm members into movement inwardly of said chamber, latch means secured to said closure for drawing the same into chamber-closing position against the effort of said biasing means, and spring means for rotating said guide means and therein-received arm members to operate said closure to fully-opened position upon release of said latch means.

3. In a pressure cooker having structure providing an enclosed food-processing chamber having an end-wall opening affording access thereinto, and a closure for said opening; a closure carrying and operating means comprising a U-shaped structure secured at its bight to said closure and having arm members extending rearwardly thereof adjacent opposite side walls of said chamber, tubular members for slidably receiving an end portion of each of said arm members, means for establishing predetermined limits of movement of said arm members relative to said tubular members, means for biasing said arm members toward one of said limits of movement, means for mounting said tubular members for rotation within said chamber, latch means for drawing said closure-carrying structure in opposition to said biasing means to releasably position the closure in chamberclosing position, and spring means engaging said tubular members to rotate said members and the said U-shaped structure carried thereby to establish the closure in fullyopen position upon release of said latch means and movement of said closure-carrying structure to the said one limit of movement of said arm members relative to said tubular members.

4. In a pressure cooker having structure providing an enclosed food-processing chamber having an access opening, a closure for said opening, said closure being wholly within said opening, and latch means for releasably securing said closure in chamber-sealing position; a closure carrying and operating means comprising structure releasably engaging said closure and having rigid, strap-Like, arm portions extending adjacent opposite side walls of said chamber, pivot means projecting into said chamber from the said side walls thereof, means rotatably mounted on each of said pivot means for supporting the respective arm portions for longitudinal and rotational displacement within said chamber, said supporting means each including at least one plate member in facing relation with a side of the associated arm portion and upper and lower bearing elements extending from said plate members transversely across the respective upper and lower surfaces of said arm portions whereby the said arm portions are guided for longitudinal movement, spring means between said arm portions and said support means for urging said closure-carrying structure inwardly of said chamber, spring mounting means disposed within said chamber in vertically and longitudinally spaced relation to said pivot means, and second spring means extending between said spring mounting means and said arm portion supporting means to urge the latter into rotation, whereby upon release of said latching means the first-named spring means will move the closure carrying structure longitudinally inwardly of said chamher and said second spring means will rotate said closure 7 carrying structure relative to said chamber access opening.

5. The combination according to claim 4, in which each of said arm portions slidably embraces the pivot means associated with its supporting means to establish fixed limits of the longitudinal movement of said arm portions relative to the supporting means.

6. A pressure cooker, comprising a walled vessel defining a cooking chamber for operation at substantial internal steam pressure and provided with an opening thereinto having a surrounding seat, a door for said opening, said door having a closed position with respect to said opening engaging said seat and positioned in said chamber closely adjacent to said opening, said door having apartialiy open position with respect to said opening disengaging said seat and positioned in said chamber a predetermined distance inwardly of said opening, said door having a fully open position with respect to said opening disengaging said seat and positioned in said chamber substantially out of alignment with said opening and disposed closely adjacent to one of the walls of said vessel, latching means releasably maintaining said door in its closed position, a carrier for said door including arms extending therefrom and guides movably supporting said arms, means pivotaly mounting said guides upon supports secured to the walls of said vessel, a lost-motion connection between said arms and said guides and establishing said predetermined distance in the movement of said door between its closed position and its partially open position, "first spring means acting between said arms and said guides for moving said arms upon said guides in order to move said door from its closed position into its partially open position upon initial movement of said latching means in an unlatching direction, and second spring means acting between said carrier and the walls of said vessel for pivoting said carrier upon said supports in order to move said door from its partially open position into its fully open position upon final movement of said latching means in an unlatching direction.

7. The pressure cooker set forth in claim 6, wherein said arms are slidably supported by said guides, and said door in its partially open position is disposed substantially in alignment with the longitudinal axis of said opening.

8. A pressure cooker, comprising a walled vessel defining a cooking chamber for operation at substantial internal steam pressure and provided with an opening thereinto having a surrounding seat, a door for said opening, said door having a closed position with respect to said opening engaging said seat and positioned in said chamber closely adjacent to said opening, said door having a partially open position with respect to said opening disengaging said seat and positioned in said chamber a predetermined distance inwardly of said opening, said door having a fully open position with respect to said opening disengaging said seat and positioned in said chamber substantially out of alignment with said opening and disposed closely adjacent to one of the walls of said vessel, latching 'r'neans releasably maintaining said door in its closed position, a carrier for said door including arms extending therefrom and guides movably supporting said arms, means pivotally mounting said guides upon supports secured to the walls of said vessel,

the movement of said door between its closed position and its partially open position, first spring means acting between said arms and said guides for moving said arms upon said guides in order to move said door from its closed position into its partially open position against the residual pressure in said chamber upon initial movement of said latching means in an unlatching direction, said first spring means having a bias which is greater than the total force against said door resulting from the residual pressure in said chamber, and second spring means acting between said carrier and the walls of said vessel for pivoting said carrier upon said supports in order to move said door from its partially open position into its fully open position upon final movement of said latching means in an unlatching direction.

9. The pressure cooker set forth in claim 8, wherein said first spring means has a bias which is greater than the total force against said door resulting from a residual pressure in said chamber of one-tenth pound per square inch gauge, whereby the movement of said door from its closed position into its partially open position completes the dissipation of steam pressure within said chamber following a food processing operation.

10. A pressure cooker, comprising a walled vessel defining a cooking chamber for operation at substantial internal steam pressure and provided with an opening thereinto having a surrounding seat, a door for said opening, said door having a closed position with respect to said opening engaging said seat and positioned in said chamber closely adjacent to said opening, said door having a partially open position with respect to said opening disengaging said seat and positioned in said chamber a predetermined distance inwardly of said opening, said door having a fully open position with respect to said opening disengaging said seat and positioned in said chamber substantially out of alignment with said opening and disposed closely adjacent to one of the walls of said vessel. latching means releasably maintaining said door in its closed position, a carrier detachably connected to said door, said carrier including arms extending therefrom and guides movably supporting said arms, means pivotally mounting said guides upon supports secured to the walls of said vessel, a lost-motion connection between said arms and said guides and establishing said predetermined distance in the movement of said door between its closed position and its partially open position,

first spring means acting between said arms and said References Cited in the file of this patent UNITED STATES PATENTS Pledger Nov. 2, 1948 Binding Feb. 10, 1953

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