CA1142988A - Electric kettle - Google Patents
Electric kettleInfo
- Publication number
- CA1142988A CA1142988A CA000337131A CA337131A CA1142988A CA 1142988 A CA1142988 A CA 1142988A CA 000337131 A CA000337131 A CA 000337131A CA 337131 A CA337131 A CA 337131A CA 1142988 A CA1142988 A CA 1142988A
- Authority
- CA
- Canada
- Prior art keywords
- rim
- copper
- aperture
- plate
- copper material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- A47J27/00—Cooking-vessels
- A47J27/21—Water-boiling vessels, e.g. kettles
- A47J27/21166—Constructional details or accessories
Landscapes
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Cookers (AREA)
Abstract
ABSTRACT
An electric kettle consists of a unitary polypropylene upper portion to which a soft copper metal bottom is attached by a leak-proof joint. The joint is formed by forming the copper bottom around a downwardly extending cylindrical lip of the upper portion, the bottom having inward of the lip a peripheral channel which permits deformation of the bottom without spoiling the seal at the joint.
An electric kettle consists of a unitary polypropylene upper portion to which a soft copper metal bottom is attached by a leak-proof joint. The joint is formed by forming the copper bottom around a downwardly extending cylindrical lip of the upper portion, the bottom having inward of the lip a peripheral channel which permits deformation of the bottom without spoiling the seal at the joint.
Description
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This invention relates to the attachment of a rnetal bottom onto an otherwise plastic container.
The invention more specifically relates to the attachment of a metal bottom plate onto a molded plastic upper portion of an electric kettle. Formerly, such kettles were made largely of metal, but due to the increasing costs of metals it was considered advantageous to develop a kettle which incorporated the largest possible proportion of a suitable plastic material.
A difficulty encountered in achieving this goal has been to provide a suitable kettle bottom. A metal bottom is desirable but a problem is created in securing a metal bottom to the plastic portion of the kettle. Such an attachment requires a joint which will be water-tight over the usual operating `` temperature range, and which possesses the necessary strength and flexibility to withstand normal day to day usage, including the likelihood of accidents such as dropping the kettle from countertop height to the floor.
In the prior art, t~he a-ttempts to connect a metal plate to the bottom of a plastic container for use in making electric appliances like kettles, coffee percolators and the like have been unsuccessful in providing a product which could maintain in a cost-efficient manner a water tight seal between plastic and metal for e~tended periods of time under conditions of heating and cooling, particularly, where the appliance was intended for operation with a heating element having a power greater than 1000 watts.
In a broad sense, the invention consists of a plastic body having a bottom closure of soft metal, the body having a peripheral, circular bead around which the closure is ;2a3~3~
.
crimped to provide a liquid seal, the closure having a peripheral inverted channel ~lwardly of the bead whereby movement of the central portion of the closure does not impair the seal.
More particularly, the present invention provides an electric appliance comprising a polypropylene container body having a bottom rim defining a circular aperture of predetermined radius7 an electrical heating means including a heating element adapted to fit within the container, terminals and an external power source in combination with a circular metal plate having a circumference of a radius greater than the radius of the aperture and having a groove around its circumference adapted to receive the rim in a snùg press fit connection to seal the aperture, the plate also supporting the heating element within the container and permitting the terminals to extend there through to make electrical connection with the external power source. The metal plate is made of soft copper material having an inverted channel like a rampart bending at an angle away from the groove just inside the rim and extending a short distarlce towards a central portion of the plate. The rampart portion is adapted to act like a spring between the joint :Eormed by the groove and the rim to permit expansion and contraction during heating and cooling while maintaining a snug connection between the rim and the groove.
It is preferred that the metal plate be made of soft copper or brass with a high content of copper. In this specification "Copper material" is used to include both substantially pure copper and brass. Brass having a copper content of less than 70% is not preferred for electric kettles as the 30%
zinc wlll leach out into water being boiled. Brass having higher copper contents is preferred and 85% copper - 15% zinc brass is quite satisfactory.
It is further preferred that the copper material is "dead soft".
The present invention also discloses an electric kettle comprising a polypropylene body that is closed at the bottom by a metal sheet, the body having at the bottom a peripheral 13 generally cylindrical lip and, spaced upwardly from the bottom edge of the lip, a peripheral outwardly extending ridge, with a peripheral indentation in the outer surface of the lip below the ridge, the metal sheet comprising a sheet of soft copper with a circular inverted peripheral inden~ation of the lip) the channel permitting deflection, expansion and contraction of the central portion of the sheet without relaxing the engagement of its periphery with the lip whereby a water~tight seal is provided between the body and~the sheet.
It has been found that electric kettles constructed in accordance with the directlons of this specification can operate with a heating element of 15G0 watts in a kettle having a diameter of less than 12 inches.
l In the preferred embodiment of this invention an integral ridge or shoulder of polypropolene is provided about the outside of the rim of the aperture to reinforce it against breaking. Further, the metal plate is brought around the rim and continued under the shoulder to provide extra stength and to provide a better seal in the joint.
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It is preferred that an indentation or neck be provided about the outside of the rim under the shoulder to provide better sealing characteristics~ The optimum angle o~ the rampart portion adjacent the groove may be determined experimentally for any particular copper material or plate diame~er. However, it is expected that angles between 70~ and 20~ from the horizontal will work satisfactorily. It is preferred that the angle be between 25 to 65. About 30-45 has been successfully used on electric kettles of about 10 inches in diameter.
It will be appreciated that the electrical heating means is con~entional and may include a thermostat. The electrical heating means is supported by the metal plate with m the container body. The terminals project through the metal plate to connect with the external power source. Where a thermostat is used, a cup shaped indentation may be provided in the center of the plate to receive the thermostat.
An electric kettle oE the appropriate design constructed in accordance with the invention has been found to be a satisfactory substitute for a conventional~all metal electric kettle.
A preferred embodiment of the invention is shown in the accompanying drawings in which:
Figure l is a perspective view of a kettle; and Figure 2 is an enlarged sectional view of the same kettle.
The upper container portion l of the ke~tle has a handle 2 and spout 3, and is formed as a unitary structure of heat resistant polypropylene manufactured by injection molding.
Referring to Figure 2, the plastic upper container portion of the kettle l has, arouna its bottom edge an ap~rture bounded by a rim comprising a peripheral generally cylindrical lip 5, 't ., - .~
around which a metal bottom 6 is snugly sealed. The metal bottom is shaped with a central circular cup shaped indented area 7, rampart portion or a peripheral circular inverted channel 8, a groove 9 which fits against the inside of the lip, 5!,~ and continues downwardly around the lower edge of the lip 5, in snug engagement therewith, then upwardly and :into an indentation 10 in the lip 5, just below an outwardly protruding shoulder or ridge ll of the upp~r container portion l and continues under ~0 ~he shouIder 11. Thus, the bottom is snugly crimped around the lip or bead 5 to provide a water-tig~t seal Preferably, the bottom 6 is made of .020 gauge dead soft copper. This material re~ains its shape when bent, and once the metal-to-plastic joint is made, the copper mainta,ins a snug engagement with the lip 5 of the polyproylene upper portion 1. The rampart portion or inverted channel portion 8 in the bottom 6 permits expansion and contraction of the metal bottom under ~arying temperature ; conditions without relaxing the engagement of the metal bottom edge around lip 5.
Below the bottom 6 is a painted steel bowl-shaped base 12 attached to the central portion of the bottom 6 by bolts 13. The upturned edge of the base 12 engages the underside of the peripheral outwardly extending ridge ll. Forces applied to the base 12 of the kettle are partly transmitted to the upper portion 1 through the rib 11. Forces transmitted to the soft copper bottom 6 through the bolts 13 may cause the bottom to deflect, but the downwardly facing peripheral channel or rampart portion 8 tends to isolate the groove 9 from such deflection so that the channel side along the lip 5 is not affected. Supported on !~he metal bottom 7 is a conventional heating element 14, with leads 15 for attachment to a cord and plug (not sho~).
In construction the polypropylene container is injection moulded as a piece. The metal plate bottom is stamped out and fitted with the electrical heating element. The metal plate is then fitted over the rim of the container and the edge or groove of the plate is rolled about the rim to cold form it in place. The connections to the electrical supply means can then be made.
It will be appreciated by those skilled in the art that the preferred embodiment may be modified without departing from the principles of this invention.
~ ~ _ ]
This invention relates to the attachment of a rnetal bottom onto an otherwise plastic container.
The invention more specifically relates to the attachment of a metal bottom plate onto a molded plastic upper portion of an electric kettle. Formerly, such kettles were made largely of metal, but due to the increasing costs of metals it was considered advantageous to develop a kettle which incorporated the largest possible proportion of a suitable plastic material.
A difficulty encountered in achieving this goal has been to provide a suitable kettle bottom. A metal bottom is desirable but a problem is created in securing a metal bottom to the plastic portion of the kettle. Such an attachment requires a joint which will be water-tight over the usual operating `` temperature range, and which possesses the necessary strength and flexibility to withstand normal day to day usage, including the likelihood of accidents such as dropping the kettle from countertop height to the floor.
In the prior art, t~he a-ttempts to connect a metal plate to the bottom of a plastic container for use in making electric appliances like kettles, coffee percolators and the like have been unsuccessful in providing a product which could maintain in a cost-efficient manner a water tight seal between plastic and metal for e~tended periods of time under conditions of heating and cooling, particularly, where the appliance was intended for operation with a heating element having a power greater than 1000 watts.
In a broad sense, the invention consists of a plastic body having a bottom closure of soft metal, the body having a peripheral, circular bead around which the closure is ;2a3~3~
.
crimped to provide a liquid seal, the closure having a peripheral inverted channel ~lwardly of the bead whereby movement of the central portion of the closure does not impair the seal.
More particularly, the present invention provides an electric appliance comprising a polypropylene container body having a bottom rim defining a circular aperture of predetermined radius7 an electrical heating means including a heating element adapted to fit within the container, terminals and an external power source in combination with a circular metal plate having a circumference of a radius greater than the radius of the aperture and having a groove around its circumference adapted to receive the rim in a snùg press fit connection to seal the aperture, the plate also supporting the heating element within the container and permitting the terminals to extend there through to make electrical connection with the external power source. The metal plate is made of soft copper material having an inverted channel like a rampart bending at an angle away from the groove just inside the rim and extending a short distarlce towards a central portion of the plate. The rampart portion is adapted to act like a spring between the joint :Eormed by the groove and the rim to permit expansion and contraction during heating and cooling while maintaining a snug connection between the rim and the groove.
It is preferred that the metal plate be made of soft copper or brass with a high content of copper. In this specification "Copper material" is used to include both substantially pure copper and brass. Brass having a copper content of less than 70% is not preferred for electric kettles as the 30%
zinc wlll leach out into water being boiled. Brass having higher copper contents is preferred and 85% copper - 15% zinc brass is quite satisfactory.
It is further preferred that the copper material is "dead soft".
The present invention also discloses an electric kettle comprising a polypropylene body that is closed at the bottom by a metal sheet, the body having at the bottom a peripheral 13 generally cylindrical lip and, spaced upwardly from the bottom edge of the lip, a peripheral outwardly extending ridge, with a peripheral indentation in the outer surface of the lip below the ridge, the metal sheet comprising a sheet of soft copper with a circular inverted peripheral inden~ation of the lip) the channel permitting deflection, expansion and contraction of the central portion of the sheet without relaxing the engagement of its periphery with the lip whereby a water~tight seal is provided between the body and~the sheet.
It has been found that electric kettles constructed in accordance with the directlons of this specification can operate with a heating element of 15G0 watts in a kettle having a diameter of less than 12 inches.
l In the preferred embodiment of this invention an integral ridge or shoulder of polypropolene is provided about the outside of the rim of the aperture to reinforce it against breaking. Further, the metal plate is brought around the rim and continued under the shoulder to provide extra stength and to provide a better seal in the joint.
~,~
It is preferred that an indentation or neck be provided about the outside of the rim under the shoulder to provide better sealing characteristics~ The optimum angle o~ the rampart portion adjacent the groove may be determined experimentally for any particular copper material or plate diame~er. However, it is expected that angles between 70~ and 20~ from the horizontal will work satisfactorily. It is preferred that the angle be between 25 to 65. About 30-45 has been successfully used on electric kettles of about 10 inches in diameter.
It will be appreciated that the electrical heating means is con~entional and may include a thermostat. The electrical heating means is supported by the metal plate with m the container body. The terminals project through the metal plate to connect with the external power source. Where a thermostat is used, a cup shaped indentation may be provided in the center of the plate to receive the thermostat.
An electric kettle oE the appropriate design constructed in accordance with the invention has been found to be a satisfactory substitute for a conventional~all metal electric kettle.
A preferred embodiment of the invention is shown in the accompanying drawings in which:
Figure l is a perspective view of a kettle; and Figure 2 is an enlarged sectional view of the same kettle.
The upper container portion l of the ke~tle has a handle 2 and spout 3, and is formed as a unitary structure of heat resistant polypropylene manufactured by injection molding.
Referring to Figure 2, the plastic upper container portion of the kettle l has, arouna its bottom edge an ap~rture bounded by a rim comprising a peripheral generally cylindrical lip 5, 't ., - .~
around which a metal bottom 6 is snugly sealed. The metal bottom is shaped with a central circular cup shaped indented area 7, rampart portion or a peripheral circular inverted channel 8, a groove 9 which fits against the inside of the lip, 5!,~ and continues downwardly around the lower edge of the lip 5, in snug engagement therewith, then upwardly and :into an indentation 10 in the lip 5, just below an outwardly protruding shoulder or ridge ll of the upp~r container portion l and continues under ~0 ~he shouIder 11. Thus, the bottom is snugly crimped around the lip or bead 5 to provide a water-tig~t seal Preferably, the bottom 6 is made of .020 gauge dead soft copper. This material re~ains its shape when bent, and once the metal-to-plastic joint is made, the copper mainta,ins a snug engagement with the lip 5 of the polyproylene upper portion 1. The rampart portion or inverted channel portion 8 in the bottom 6 permits expansion and contraction of the metal bottom under ~arying temperature ; conditions without relaxing the engagement of the metal bottom edge around lip 5.
Below the bottom 6 is a painted steel bowl-shaped base 12 attached to the central portion of the bottom 6 by bolts 13. The upturned edge of the base 12 engages the underside of the peripheral outwardly extending ridge ll. Forces applied to the base 12 of the kettle are partly transmitted to the upper portion 1 through the rib 11. Forces transmitted to the soft copper bottom 6 through the bolts 13 may cause the bottom to deflect, but the downwardly facing peripheral channel or rampart portion 8 tends to isolate the groove 9 from such deflection so that the channel side along the lip 5 is not affected. Supported on !~he metal bottom 7 is a conventional heating element 14, with leads 15 for attachment to a cord and plug (not sho~).
In construction the polypropylene container is injection moulded as a piece. The metal plate bottom is stamped out and fitted with the electrical heating element. The metal plate is then fitted over the rim of the container and the edge or groove of the plate is rolled about the rim to cold form it in place. The connections to the electrical supply means can then be made.
It will be appreciated by those skilled in the art that the preferred embodiment may be modified without departing from the principles of this invention.
Claims
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electric appliance comprising; a polypropylene container body having a bottom rim defining a circular aperture of predetermined radius, an electrical heating means including a heating element adapted to fit within the container, terminals and an external electrical power source, a circular metal plate having a circumference of a radius greater than the radius of the aperture, said plate having a groove around its circumference adapted to receive the rim in a snug press fit connection to seal the aperture, said plate supporting the element within the container and permitting the terminals to extend through the plate to make electrical connection with the external power source, in which said plate is made of a soft copper material having a rampart portion bending away from said groove at an angle and extending a short distance towards a central portion of the plate, said rampart portion being adapted to permit deflection, expansion and contraction of the plate during heating and cool mg while maintaining the snug connection between the rim and the groove.
2. The invention defined by Claim 1 wherein the copper material is substantially pure copper.
3. The invention defined by Claim 1 wherein the copper material is brass having a mixture in the range of 70% or more copper with 30% or less zinc, respectively.
4. The invention defined by Claim 1 in which the copper material is brass having a mixture in the range of 80% or more copper with 20% or less zinc respectively.
5. The invention of Claims 2, 3 or 4 in which the copper material is dead soft.
6. The invention defined by Claim 1 in which the copper material is brass being about 85% copper and 15% zinc.
7. The invention of Claim 6 in which the brass is dead soft.
8. The invention defined in Claims 1, 2 or 3 where the electrical heating means has a power output of greater than 500 watts.
9. The invention defined in Claims 1, 2 or 3 in which the power output of the electrical heating means is greater than 1000 watts.
10. The invention defined in Claims 1, 2 or 3 where the power output of the electrical heating means is about 1500 watts.
11, The invention defined in Claim 1 having a shoulder about the outside of the rim to provide increased strength against radial deflection.
12. The invention defined by Claim 11 in which the groove of the metal plate has an outside peripheral flange adapted to fit under said shoulder.
13. The invention defined by Claims 11 and 2.
14. The invention defined by Claims 11 and 3.
15. The invention defined by Claims 11 and 4.
16. An electrical appliance comprising, a polypropylene container body having a bottom rim defining a circular aperture of predetermined radius and having an integral shoulder slightly above the aperture outside the rim, an electrical heating means including a heating element adapted to fit within the container, terminals and an external electrical power source, said heating means having a power greater than 1000 watts, a circular metal plate of a soft copper material having a circumference of a radius greater than the radius of the aperture, said plate having a flange around its circumference adapted to fit under said shoulder, having, next within a groove adapted to fit about the rim in a snug press fit connection and having, next within, a rampart portion bending away from the groove inside the rim at an angle between 20° and 70° from a horizontal plane towards a central portion of the plate for a short distance to permit expansion and contraction of the plate during heating and cooling while maintaining the snug connection between the rim and the groove, said central portion of the plate supporting the element within the container and permitting the terminals to extend through to make electrical connection with the external power source.
17. The invention of Claim 16 in which the copper material is substantially pure copper.
18. The invention of Claim 16 in which the copper material is brass having a mixture range of 80% or more copper with 20% or less zinc.
19. The invention of Claim 16 in which the copper material is brass having a mixture of about 85% copper and 15% zinc.
The invention of Claims 17, 18 or 19 in which the copper material is dead soft.
21. The invention of Claims 17, 18 or 19 in which the angle of the rampart portion is between 25° and 65° from a horizontal plane.
22. The invention of Claims 17, 18 or 19 in which the copper material is dead soft and the angle of the rampart portion is between 25° and 65° from a horizontal plane.
23. An electrical kettle comprising, polypropylene container body having a bottom rim defining a circular aperture of a radius between 8 and 10 inches and having an integral, peripheral shoulder slightly above the aperture outside the rim, an electrical heating means including a heating element adapted to fit within the container, terminals, a thermostat and an external power source, said heating means having a power greater than 1000 watts, a circular metal plate of a soft copper material of a radius greater than the radius of the aperture but within the shoulder, said plate having a flange around its circumference adapted to fit under said shoulder, having next a groove adapted to fit about the rim in a snug press fit connection and having next a rampart portion bending away from the groove inside the rim at an angle in the range of 25° to 65° from the horizontal towards a central portion of the plate for a distance in the range of 0.5 to 1 inches, the central portion being flat thereafter to an upward cup-shaped indentation adapted to contain the thermostat, said plate supporting the element within the container and per-mitting the terminals to protrude through the plate to con-nect to the external power source and permitting the thermostat to protrude through to the element.
24. The electric kettle of Claim 23 in which the rim depends vertically downward from the bottom of the aperture, curves under, out and upwards into an indentation above the bottom of the rim and beneath the shoulder, and in which the flange of the metal plate is adapted to fit under the shoulder and the groove is adapted to fit in a snug press fit connection into the said indentation, around the underside of the rim and up inside the rim to a position near the top of the shoulder, and in which the rampart portion slants downward from the groove inside the rim at an angle from the horizontal of between 25° and 50°.
25. The electric kettle of Claim 24 in which the copper material is dead soft copper.
26. The electric kettle of Claim 24 in which the copper material is dead soft brass.
27. The electric kettle of Claim 24 in which the copper material is dead soft brass in the range of 80% copper or more to 20% zinc or less.
28. The electric kettle of Claim 24 in which the copper material is soft brass of about 85% copper and 15% zinc.
29. The electric kettle of Claim 24 in which the copper material is dead soft brass of about 85% copper and 15% zinc.
30. An electrical kettle comprising, a polypropylene container body having a bottom rim defining a circular aperture of a diameter between 8 and 10 inches, said rim having a first portion within the aperture, a second portion curving from within the aperture to outside the aperture, a third portion extending upwards and into a neck portion, and said body having an integral, peripheral shoulder with a flat underside encircling the body next above the neck, an elec-trical heating means including a heating element adapted to fit within the container, a thermostat, terminals and an electrical power source, said electrical heating means having a power greater than 1000 watts and being adapted to heat water within the kettle, a circular soft metal plate of a soft copper material of a radius greater than the radius of the aperture but within the shoulder, said plate having an integral flange about its circumference adapted to fit against the underside of the shoulder, said metal plate having next within said flange, an integral groove adapted to fit in snug press fit connection about the neck, the third portion, the second portion, the first portion of the rim and up within the aperture to a position opposite the shoulder above the neck portion, said metal plate having, next within said groove, an integral rampart portion downwardly depending from the groove inside the rim of the aperture at an angle in the range of 25° - 50° from the horizontal over a horizontal distance of between 0.5 to 1.0 inches, being adapted to help secure the snug fit of the groove about the rim during heat-ing and cooling, said metal plate having, next within said rampart portion, a flat horizontal portion adapted to permit location of the terminals for the element and the like, said metal plate having, next within the flat horizontal portion, an indentation adapted to receive a thermostat for control of the power source, said metal plate being adapted to seal the aperture about the rim and to provide a support for the electrical heating means.
31. The electrical kettle of Claim 30 having a bowl shaped based under the shoulder and the metal plate and attached to said plate, said bowl being adapted to provide a base for the kettle and to cover the metal plate, the terminals and the thermostat.
32. The electrical kettle of Claim 30 wherein the soft copper material is brass being about 85% copper and 15% zinc.
33. An electric kettle comprising a polypropylene body that is closed at the bottom by a metal sheet, the body having at the bottom a peripheral generally cylindrical lip and spaced upwardly from the bottom edge of the lip, a peripheral outwardly extending ridge, with a peripheral indentation in the outer surface of the lip below the ridge, the metal sheet comprising a sheet of soft copper with a circular in-verted peripheral channel one side of which fits snugly against the inside of the lip and continues, in snug engage-ment, with the lip, under the lip and then upwardly into the peripheral indentation of the lip, the channel permitting deflection, expansion and contraction of the central portion of the sheet without relaxing the engagement of its periphery with the lip whereby a water-tight seal is provided between the body and the body and the sheet.
34. A kettle as claimed in Claim 33, including a metal cup-shaped base having an upper peripheral edge engaging the outwardly extending ridge, the base and said sheet being fastened together at the central portion of the sheet.
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electric appliance comprising; a polypropylene container body having a bottom rim defining a circular aperture of predetermined radius, an electrical heating means including a heating element adapted to fit within the container, terminals and an external electrical power source, a circular metal plate having a circumference of a radius greater than the radius of the aperture, said plate having a groove around its circumference adapted to receive the rim in a snug press fit connection to seal the aperture, said plate supporting the element within the container and permitting the terminals to extend through the plate to make electrical connection with the external power source, in which said plate is made of a soft copper material having a rampart portion bending away from said groove at an angle and extending a short distance towards a central portion of the plate, said rampart portion being adapted to permit deflection, expansion and contraction of the plate during heating and cool mg while maintaining the snug connection between the rim and the groove.
2. The invention defined by Claim 1 wherein the copper material is substantially pure copper.
3. The invention defined by Claim 1 wherein the copper material is brass having a mixture in the range of 70% or more copper with 30% or less zinc, respectively.
4. The invention defined by Claim 1 in which the copper material is brass having a mixture in the range of 80% or more copper with 20% or less zinc respectively.
5. The invention of Claims 2, 3 or 4 in which the copper material is dead soft.
6. The invention defined by Claim 1 in which the copper material is brass being about 85% copper and 15% zinc.
7. The invention of Claim 6 in which the brass is dead soft.
8. The invention defined in Claims 1, 2 or 3 where the electrical heating means has a power output of greater than 500 watts.
9. The invention defined in Claims 1, 2 or 3 in which the power output of the electrical heating means is greater than 1000 watts.
10. The invention defined in Claims 1, 2 or 3 where the power output of the electrical heating means is about 1500 watts.
11, The invention defined in Claim 1 having a shoulder about the outside of the rim to provide increased strength against radial deflection.
12. The invention defined by Claim 11 in which the groove of the metal plate has an outside peripheral flange adapted to fit under said shoulder.
13. The invention defined by Claims 11 and 2.
14. The invention defined by Claims 11 and 3.
15. The invention defined by Claims 11 and 4.
16. An electrical appliance comprising, a polypropylene container body having a bottom rim defining a circular aperture of predetermined radius and having an integral shoulder slightly above the aperture outside the rim, an electrical heating means including a heating element adapted to fit within the container, terminals and an external electrical power source, said heating means having a power greater than 1000 watts, a circular metal plate of a soft copper material having a circumference of a radius greater than the radius of the aperture, said plate having a flange around its circumference adapted to fit under said shoulder, having, next within a groove adapted to fit about the rim in a snug press fit connection and having, next within, a rampart portion bending away from the groove inside the rim at an angle between 20° and 70° from a horizontal plane towards a central portion of the plate for a short distance to permit expansion and contraction of the plate during heating and cooling while maintaining the snug connection between the rim and the groove, said central portion of the plate supporting the element within the container and permitting the terminals to extend through to make electrical connection with the external power source.
17. The invention of Claim 16 in which the copper material is substantially pure copper.
18. The invention of Claim 16 in which the copper material is brass having a mixture range of 80% or more copper with 20% or less zinc.
19. The invention of Claim 16 in which the copper material is brass having a mixture of about 85% copper and 15% zinc.
The invention of Claims 17, 18 or 19 in which the copper material is dead soft.
21. The invention of Claims 17, 18 or 19 in which the angle of the rampart portion is between 25° and 65° from a horizontal plane.
22. The invention of Claims 17, 18 or 19 in which the copper material is dead soft and the angle of the rampart portion is between 25° and 65° from a horizontal plane.
23. An electrical kettle comprising, polypropylene container body having a bottom rim defining a circular aperture of a radius between 8 and 10 inches and having an integral, peripheral shoulder slightly above the aperture outside the rim, an electrical heating means including a heating element adapted to fit within the container, terminals, a thermostat and an external power source, said heating means having a power greater than 1000 watts, a circular metal plate of a soft copper material of a radius greater than the radius of the aperture but within the shoulder, said plate having a flange around its circumference adapted to fit under said shoulder, having next a groove adapted to fit about the rim in a snug press fit connection and having next a rampart portion bending away from the groove inside the rim at an angle in the range of 25° to 65° from the horizontal towards a central portion of the plate for a distance in the range of 0.5 to 1 inches, the central portion being flat thereafter to an upward cup-shaped indentation adapted to contain the thermostat, said plate supporting the element within the container and per-mitting the terminals to protrude through the plate to con-nect to the external power source and permitting the thermostat to protrude through to the element.
24. The electric kettle of Claim 23 in which the rim depends vertically downward from the bottom of the aperture, curves under, out and upwards into an indentation above the bottom of the rim and beneath the shoulder, and in which the flange of the metal plate is adapted to fit under the shoulder and the groove is adapted to fit in a snug press fit connection into the said indentation, around the underside of the rim and up inside the rim to a position near the top of the shoulder, and in which the rampart portion slants downward from the groove inside the rim at an angle from the horizontal of between 25° and 50°.
25. The electric kettle of Claim 24 in which the copper material is dead soft copper.
26. The electric kettle of Claim 24 in which the copper material is dead soft brass.
27. The electric kettle of Claim 24 in which the copper material is dead soft brass in the range of 80% copper or more to 20% zinc or less.
28. The electric kettle of Claim 24 in which the copper material is soft brass of about 85% copper and 15% zinc.
29. The electric kettle of Claim 24 in which the copper material is dead soft brass of about 85% copper and 15% zinc.
30. An electrical kettle comprising, a polypropylene container body having a bottom rim defining a circular aperture of a diameter between 8 and 10 inches, said rim having a first portion within the aperture, a second portion curving from within the aperture to outside the aperture, a third portion extending upwards and into a neck portion, and said body having an integral, peripheral shoulder with a flat underside encircling the body next above the neck, an elec-trical heating means including a heating element adapted to fit within the container, a thermostat, terminals and an electrical power source, said electrical heating means having a power greater than 1000 watts and being adapted to heat water within the kettle, a circular soft metal plate of a soft copper material of a radius greater than the radius of the aperture but within the shoulder, said plate having an integral flange about its circumference adapted to fit against the underside of the shoulder, said metal plate having next within said flange, an integral groove adapted to fit in snug press fit connection about the neck, the third portion, the second portion, the first portion of the rim and up within the aperture to a position opposite the shoulder above the neck portion, said metal plate having, next within said groove, an integral rampart portion downwardly depending from the groove inside the rim of the aperture at an angle in the range of 25° - 50° from the horizontal over a horizontal distance of between 0.5 to 1.0 inches, being adapted to help secure the snug fit of the groove about the rim during heat-ing and cooling, said metal plate having, next within said rampart portion, a flat horizontal portion adapted to permit location of the terminals for the element and the like, said metal plate having, next within the flat horizontal portion, an indentation adapted to receive a thermostat for control of the power source, said metal plate being adapted to seal the aperture about the rim and to provide a support for the electrical heating means.
31. The electrical kettle of Claim 30 having a bowl shaped based under the shoulder and the metal plate and attached to said plate, said bowl being adapted to provide a base for the kettle and to cover the metal plate, the terminals and the thermostat.
32. The electrical kettle of Claim 30 wherein the soft copper material is brass being about 85% copper and 15% zinc.
33. An electric kettle comprising a polypropylene body that is closed at the bottom by a metal sheet, the body having at the bottom a peripheral generally cylindrical lip and spaced upwardly from the bottom edge of the lip, a peripheral outwardly extending ridge, with a peripheral indentation in the outer surface of the lip below the ridge, the metal sheet comprising a sheet of soft copper with a circular in-verted peripheral channel one side of which fits snugly against the inside of the lip and continues, in snug engage-ment, with the lip, under the lip and then upwardly into the peripheral indentation of the lip, the channel permitting deflection, expansion and contraction of the central portion of the sheet without relaxing the engagement of its periphery with the lip whereby a water-tight seal is provided between the body and the body and the sheet.
34. A kettle as claimed in Claim 33, including a metal cup-shaped base having an upper peripheral edge engaging the outwardly extending ridge, the base and said sheet being fastened together at the central portion of the sheet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000337131A CA1142988A (en) | 1979-10-05 | 1979-10-05 | Electric kettle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000337131A CA1142988A (en) | 1979-10-05 | 1979-10-05 | Electric kettle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1142988A true CA1142988A (en) | 1983-03-15 |
Family
ID=4115299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000337131A Expired CA1142988A (en) | 1979-10-05 | 1979-10-05 | Electric kettle |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1142988A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5702623A (en) * | 1994-07-07 | 1997-12-30 | Pifco Limited | Heating apparatus |
-
1979
- 1979-10-05 CA CA000337131A patent/CA1142988A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5702623A (en) * | 1994-07-07 | 1997-12-30 | Pifco Limited | Heating apparatus |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |