GB2120578A

GB2120578A - Improvements in or relating to pressure cookers

Info

Publication number: GB2120578A
Application number: GB08210874A
Authority: GB
Inventors: Peter Bolton
Original assignee: TI TOWER HOUSEWARES Ltd
Current assignee: TI TOWER HOUSEWARES Ltd
Priority date: 1982-04-14
Filing date: 1982-04-14
Publication date: 1983-12-07
Also published as: GB2120578B

Abstract

A pressure cooker is provided with a safety valve which prevents the build-up of pressure inside the cooker should a cooking process be commenced with the lid of the cooker incorrectly secured in place. The body (8) of the cooker has secured to it a spring strip (13) whose end projects through a window (12) in the peripheral wall (7) of the pressure cooker lid (1) to displace from its sealing position an annular sealing gasket (6) carried by the lid unless the latter is correctly engaged on the pressure cooker body. <IMAGE>

Description

SPECIFICATION Improvements in or relating to pressure cookers This invention relates to pressure cookers and principally to pressure cookers for domestic use.

Such cookers may incorporate a built-in heat source, e.g. an electric heater element, or they may have to be used with an independent heat source, e.g. a gas or electric ring.

Many conventional domestic pressure cookers have a lid that is removably secured to the body of the cooker by means of a bayonet-type connection, both lid and body having peripheral segments that are aligned one with another by rotation of the lid relatively to the body portion once the lid has been piaced in position on the body portion. A resilient sealing gasket housed in the lid effects a seal between lid and body portion.

The correct alignment of the segments on the lid and body portion is indicated by the "in-line" position of the handle on both lid and body portion.

It has been found that a user does not always ensure that the handles are in the "in-line" position, i.e. that the lid and body portion segments are correctly aligned before commencing a cooking operation. Although the segments may not be correctly aligned, a degree of sealing by the gasket between the lid and the body portion is provided so that once the cooking operation is commenced the pressure inside the cooker starts to increase. That increase will effectively lock the lid on the body portion and will prevent rotation of the lid to bring the handle into the "in-line" position. However, in some positions of the handle; the "lock" will not prevent rotation of the lid in the releasing direction and if this is attempted by a user the lid may be blown off possibly with some force.

It is an object of the present invention to provide a pressure cooker having a safety device that eliminates the risks described above.

According to the present invention, a pressure cooker includes, on the lid of the cooker or on the body portion thereof, means for venting the interior of the cooker to atmosphere, the means having a venting and a non-venting position and being operable by a surface on the body portion or on the lid to a non-venting position only when the lid is correctly positioned for a pressure cooking operation.

Preferably, the means comprises a device for maintaining in a non-sealing orientation part at least of a sealing gasket of the pressure cooker. In this case, the surface operates to move the device, when the lid is correctly positioned for a pressure cooking operation, and allow the sealing gasket or the part thereof to adopt a sealing orientation.

The device may include a strip of resilient material one end of which displaces a part of the sealing gasket from its sealing orientation. The strip is secured to the lid adjacent an aperture in the latter positioned to allow movement of one end of the strip by a surface on the body portion of the cooker.

The surface is preferably that of one of the segments by which the lid is locked to the body portion of the pressure cooker.

By way of example only, a domestic pressure cooker embodying the invention will now be described in greater detail with reference to the accompanying drawings of which: Fig. 1 is a side view partly in section of the domestic pressure cooker, Fig. 2 is a view from above of a part of the pressure cooker, Figs. 3 and 4 are, respectiveiy, front view and section on line IV--IV of a component, Fig. 5 is a front view of a detail, Fig. 6 is a section on the line VI--VI of Fig, 5, and, Fig. 7 is an underneath view of a detail.

The domestic pressure cooker shown in Fig. 1 is of the type requiring an external source of heat and is basically of conventional design.

The cooker has a lid 1 with a handle 2.

Mounted upon the lid 1 is pressure relief valve 3 that controls in any of the known ways, the cooking pressure inside the cooker. The lid 1 also carries a safety valve 4 that vents to atmosphere in the event that the cooking pressure exceeds a predetermined value above that controlled by the relief valve 3.

The lid 1 has an internal peripheral seat 5 on which is located a resilient, annular sealing gasket 6 of conventional design. Adjacent the seat 5 the lid has a circumferential wall 7 formed, in known manner, with a series of spaced-inwardiyextending segments 7a that co-operate with a series of similar but outwardly-extending segments 8a (Fig. 2) on the body portion 8 of the cooker.

As canbe seen in Figs. 1 and 2, the upper surface of the segments 7a on the lid 1 and the undersurface of the segments 8a on the body portion 8 are contoured as at 9, Fig. 1 and 10, Fig.

2 respectively, in the weli known manner to provide a degree of lid to body in the event that an attempt is made to remove the lid when the cooker is under pressure.

The segments 7a on the lid are so positioned relatively to the segments 8a on the body portion 8 that when the lid 1 is placed on the body portion with the lid handle 2 making an angle of some 400 with the handle 11 of the body portion 8, the segments 7a on the lid locate between the segments 8a and can be located beneath the latter when the lid is rotated to bring the handle 2 into registration with the handle 11.

The peripheral wall 7 has a rectangular window 12 formed in it, the window being positioned relative to one of the lid segments as shown in Figs. 1 and 5.

Secured to the inside face of the wall 7 is a stainless steel spring strip 1 3 of the form shown in Figs. 3 and 4. One end of the strip 1 3 is rolled over as at 14 to form a closed loop whilst adjacent its other end, the strip has a hole 1 5 located in a recessed area of the strip as shown.

The strip is secured to the inside face of the wall 7 by a rivet 1 6 that passes through hole 1 5 and into the wall, the roll 14 being positioned in the window 12 as indicated in Figs. 5 and 6.

In the unstressed position of the spring 13, i.e.

the position shown in full lines in Fig. 6, the rolled end 1 4 presses against the sealing gasket 6 located in the lid 1 and moves a part of the gasket into a position in which it cannot effect a seal between the lid and the body portion. This is shown in Fig. 6, the "wings" 6a of the gasket being clear of co-operating surfaces on the lid 1 and body portion 8.

The location of the roll 14 with respect to the immediately adjacent segment on the lid and the segment on the body portion which co-operates with the lid segment is such that the roll 14 is moved outwardly by the segment on the body portion through the window to the position shown in dotted lines in Fig. 7 only when the segments on the lid are all fully and correctly engaged with those on the body portion and the handle 2 is aligned with the handle 11.

Fig. 7 shows the spring 1 3 in its unstressed condition, the roll 14 displacing the gasket 6 inwardly to the position shown in Figs. 6 and 7.

The roll 14 is then located between two segments 8a on the body portion 8. As the lid 1 is moved relatively to the body portion 8 to align the handles thereon - an anti-clockwise movement of the lid 1 as viewed in Fig. 7-the leading edge 8b of the left-hand segment 8a forces the roll 14 outwardly through the window to the dotted position shown in Fig. 7 thereby allowing the gasket 6 to return to its sealing orientation. The roll 13 is held in its Fig. 7 dotted line position by the edge 8c of the left-hand segment 8a, this position of the lid being that in which the lid handle 2 is aligned with the body portion handle 12, i.e. the position in which the lid segments and fully and correctly engaged with the body portion segments.

In that way, pressure build-up inside the cooker during use is prevented unless the lid is correctly positioned for a pressure cooking operation.

It will be appreciated that movement of the roll 14 necessary to allow the seal 6 to adopt its correct sealing position is brought about automatically as the user locks the lid in position in readiness for a pressure cooking operation.

Moreover, the additional components required are few in number, and relatively inexpensive.

It will be appreciated that an alternative although slightly more involved method of preventing pressure build-up inside the cooker when the lid is not fully locked to the body portion, is to fit the lid or the body portion with a valve that is normally open so venting the inside of the cooker to atmosphere. The valve is so located that it is closed by a segment on either the body portion or the lid only when the latter is correctly positioned for a pressure cooking operation.

Claims

1. A pressure cooker having, on the lid or the body portion thereof, means for venting the interior of the cooker to atmosphere, the means having a venting and a non-venting position and being operable by a surface on the body portion or on the lid to a non-venting position only when the lid is correctly positioned for a pressure cooking operation.

2. A cooker as claimed in claim 1 in which the venting means includes a device for maintaining in a non-sealing orientation part at least of a sealing gasket of the cooker, correct positioning of the lid allowing the sealing gasket or the part thereof to adopt a sealing orientation.

3. A cooker as claimed in claim 2 in which the device includes a strip of resilient material a part of which displaces a part of the sealing gasket from its sealing orientation.

4. A cooker as claimed in claim 3 in which the strip is secured to the lid adjacent an aperture in the latter so positioned as to allow movement of the strip into the aperture by a surface on the body portion when the lid is correctly positioned, said strip movement being sufficient to allow the part of the gasket to adopt a sealing orientation.

5. A domestic pressure cooker substantially as herein described with reference to and as illustrated by the accompanying drawings.

5. A cooker as claimed in claim 1 in which the device comprises a valve that is normally open to vent the interior of the cooker to atmosphere and is closed when the lid is correctly positioned for a pressure cooking operation.

6. A cooker as claimed in any one of the preceding claims in which the surface is that of one of the segments by which the lid is locked to the body portion for a pressure cooking operation.

7. A domestic pressure cooker substantially as herein described with reference to and as illustrated by the accompanying drawings.

New claims or amendments to claims filed on 16.5.83.

Superseded claims-All.

New or amended claims

1. A pressure cooker having a lid portion and a body portion, a sealing member for sealing the lid portion to the body portion, and a strip of resilient material positioned to co-operate with the sealing member to displace part at least of the sealing member to a non-sealing orientation, the strip being movable when the lid portion is correctly positioned for a pressure cooking operation, to allow the sealing member to adopt completely a sealing orientation.

2. A cooker as claimed in claim 1, in which the strip is mounted on the cooker adjacent an aperture into which the strip is movable to allow the sealing member to adopt completely a sealing orientation.

3. A cooker as claimed in claim 1 or claim 2, in which the strip is mounted on one of the said lid and body portions and is movable by a surface on the other portion when the lid portion is correctly positioned for a pressure cooking operation, to allow the sealing member to adopt completely a sealing orientation.

4. A cooker as claimed in Claim 3, in which the surface is that of one of the segments by which the lid portion is locked to the body portion for a pressure cooking operation.