Title of Invention	A NOVEL PRESSURE COOKER WITH REINFORCED SHORT LIP AND A PROCESS OF MAKING THE SAME
Abstract	A novel pressure cooker having a reinforced short lip with a protrusion length from the inner body wall is in between 10 to 13mm and having thickness greater than the thickness of the input raw material. The enhanced density and strength of lip is achieved by drawing the material from the body side of the pressure cooker and adding the material at the lip before the lip formation stage.

Full Text

This invention in general relates to household appliances. In particular this invention is concerned with pressure cooker. More particularly this invention relates to a novel construction of pressure cooker made of wrought Aluminium/Aluminium alloy. Especially this invention relates to a novel technology used in the process of manufacturing pressure cooker. Therefore this invention relates to a novel technology, a novel process and a novel product. Aluminium pressure cookers already known are made from heavy gauge material with long lip, which tends to gradually deform or distort during usage leading to weakening of the mouth and early obsolescence of Pressure Cooker. Moreover some companies manufactured pressure cooker in thinner gauge material with long lip keeping the view of cost reduction which further increased the rate of defect frequently. Pressure cooker (Fig.l) consists of a body (1), a lid (2), a gasket (3), pressure regulating device known as vent weight or weight valve (4), handle (5) and other safety features. The size of the body and the matching lid decide the capacity of the pressure cooker. The capacity indicates the inside volume of the pressure cooker when measured in the closed condition. While using the pressure cooker for cooking purpose, water and the food material to be cooked are kept inside and put on a stove, so that the heat is applied to the base The steam generated inside is not allowed to escape until the required steam pressure is developed. The excess pressure is controlled by the pressure regulating device by letting it out and closing. Due to the steam under pressure the food gets cooked faster than open vessel cooking. The pressure developed inside acts on all the sides and would fend to separate the fid from the bottom. The lid is held in its position until the lip of the bottom or locking Up of the lid or both give way. The maximum pressure held by the pressure cooker depends on the strength of the locking faces, referred as bursting strengh of the Pressure Cooker. From the study of our R & D all conventional Aluminium pressure cookers including our own brand have long lip (Fig.2) generally 15 +/- i 0mn with thickness as per the table below. The long lip thickness is nearly equivalent to the thickness of raw material used to produce the Pressure Cooker torn wrought aluminium disc. In these kinds of pressure cookers the long lip generally tend to deform in long usage as illustrated in Fig, 3. Ultimately there could be the chance of reduction in bursting strength as specified by Bureau of Indian Standards through IS2347 which stands for safety of consumer. So this type of Conventional Pressure Cooker may 1. Reduce the Span life of usage of Pressure Cooker. 2. Lead to a potential danger to the user after long usage. OBJECT OF THE INVENTION The object of the invention is to identify the problem associated with the Pressure Cooker of long lip and invent a novel pressure cooker with reinforced short lip, which will not have above drawbacks. The primary object of the invention accordingly is to overcome such defect in pressure cooker with long lip made out of Heavier/Thinner gauge raw material and construct a novel pressure cooker with reinforced short lip by usage of least input material with lower gauge thickness- Another object of the invention is to invent a novel method of maufacturing pressure cooker with reinforced short lip. Another object of invention is to invent a pressure cooker with reinforced short lip, which is sturdy and economical Further objects of the invention will be clear from the description of the invention. BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES Fig.l: - Shows the parts of a conventional pressure cooker- Fig,2: - Shows the sectional view of long lip in conventional pressure cooker. Fig.3. - Shows the illustration of gradual deformation of long lip of conventional pressure cooker. Fig,4: - Shows our Novel pressure cooker with reinforced short lip in elevation. Fig.5: - Shows the sectional view of reinforced short lip. Fig.6: - Shows the parts and illustration of second draw process tool- NOVEL PRESSURE COOKER WITH REINFORCED SHORT LIP The novel Pressure Cooker with reinforced short lip which made of a bottom and a lid from raw material of Aluminium/Aluminium alloy (Fig-4); The bottom having short lip of 10 to 13mm at the open end. The said short lip (Fig. 5) having thickness as per the table given below. The lip thickness is relatively increased more than the raw material thickness by a novel process. The said short iip by virtue of its increased strength through the Novel process withstands enhanced pressure. A novel process of manufacturing pressure cooker comprises the following steps. a. Deep drawing operation of raw material from circle to open cylindrical vessel. b. Second draw to add material at the lip from the body side by designing a special annular space in tool as per figure No.6 which accumulates raw material near rim area by method of ironing. The figure 6 shows the parts of second draw tool such as Die(l), Product(2), Ram(3) and Pressure pad(4). c. To compress and arrest the molecular structure of raw material at specified area, the Lip is forged with greater force to 1. Enhance the strength of the rim 2. Improve the resistance to wear at rim area 3. Improve the rigidity of rim. d. Lip forming to a reduced length of 10 to 13mm which greatly resists more amount of force of leverage to prevent deformation in long usage. Now the invention will be described in detail with reference to figures 4,5 & 6 accompanying this specification. The description of the invention will be with reference to the figures accompanying the complete specification where in fig. 4 of the drawings shows the novel pressure cooker with reinforced short lip in elevation. The constructional details of the invention are as follows. The novel pressure cooker with reinforced short lip made of Aluminium/Aluminium alloy, with the incorporation of the invention, empfoys least input of raw materia! with lower gauge thickness. A forging operation of the circular rim is carried out in the process of manufacturing to strengthen the rim. The invention includes construction of short lip in the cooker bottom that engages with the lid. Additional material is added to the original thickness at the ]ip portion by the drawing material from the wall, during the draw operation (Fig.6), This invention improves the rigidity of the lip and resists de-shaping due to continuous usage of pressure cooker. The result of which experienced through continuous efforts of our Research and Development and many tests carried out in house as given below. In accordance to Bureau of Indian Standard any conventional pressure cooker having Jong lip made out of heavier gauge raw material should withstands 6 Kg per square cm and the result on tests were observed was also up to a maximum of 6,3 Kg. per square cm for thicker gauge material and up to a maximum of 5 Kg- for thinner gauge material whereas this novel pressure cooker 1 with reinforced short lip withstands 7.0 to 7.6 Kg. per square cm even at lower gauge raw material- TEST PROCEDURE OF PRESSURE COOKER TO ASSESS BURST STRENGTH IN ACCORDANCE TO rS.2347 :1995. The cooker shall be coupled to a hydraulic test pump provided with a Calibrated pressure gauge, suitably graduated. AH the remaining openings in the body and lid of the cooker shall be suitably sealed. A gradually increasing hydraulic pressure shall be applied to the vessel of the cooker until: a) a rupture takes place, or b) a deformation occurs so that an appreciable leakage takes place at the joint of the lid or else where. The maximum gauge pressure obtained shall be taken as the bursting pressure of the cooker for the purpose of this standard IS 2347, which is 6 Kg. per square cm. SALIENT FEATURES OF THE INVENTIONS AS FOLLOWS A novel pressure cooker with reinforced short lip made of Aluminium/Aluminium alloy having a body and a lid with least raw material The lip is constructed short between 10 to 13mm with increased thickness to the input raw material to resist deformation and hence to improve the life span of the pressure cooker. The lip is formed by a forging process to increase the strength of the material at that portion. A novel process of manufacturing pressure cooker comprises the following steps- a. Deep drawing operation of raw material from circle to a open cyiindricai vessel. b. Second draw to add material at the lip from the body side. c. Forging operation of the Up, d. Lip forming ADVANTAGES • Low use of raw material. • Holds higher pressure repeatedly. • Higher safety to the user. • Lower cost of manufacturing. • Increased life span of usage WE CLAIM 1, A novel pressure cooker with reinforced short lip made of Aluminium/Aluminium alloy with the least input of raw material, the said pressure cooker having a body and a ltd, the body with a short lip wherein the protrusion length from the inner body wall is in between 10 to 13mm and having thickness greater than the thickness of input raw material. 2. The novel pressure cooker with reinforced short lip as claimed in claim 1 wherein the said short lip will not deform in the repeated application of cooking pressure without loosing its burst strength of 7.0 to 7.6 Kg- per square cm. 3. A novel process ofmanufacturing pressure cooker with reinforced short lip as claimed in claim I wherein the protrusion length of the short lip from the inner body wall is in between 10 to 13mm having thickness greater than the thickness of input raw material comprising the steps of deep drawing operation of raw material from circle to a open cylindrical vessel, lip formation by forging characterised in that before the lip formation, the a. Deep drawing operation of raw material from circle to a open cyiindricai vessel. b. Second draw to add material at the lip from the body side. c. Forging operation of the Up, d. Lip forming ADVANTAGES • Low use of raw material. • Holds higher pressure repeatedly. • Higher safety to the user. • Lower cost of manufacturing. • Increased life span of usage WE CLAIM 1, A novel pressure cooker with reinforced short lip made of Aluminium/Aluminium alloy with the least input of raw material, the said pressure cooker having a body and a ltd, the body with a short lip wherein the protrusion length from the inner body wall is in between 10 to 13mm and having thickness greater than the thickness of input raw material. 2. The novel pressure cooker with reinforced short lip as claimed in claim 1 wherein the said short lip will not deform in the repeated application of cooking pressure without loosing its burst strength of 7.0 to 7.6 Kg- per square cm. 3. A novel process ofmanufacturing pressure cooker with reinforced short lip as claimed in claim I wherein the protrusion length of the short lip from the inner body wall is in between 10 to 13mm having thickness greater than the thickness of input raw material comprising the steps of deep drawing operation of raw material from circle to a open cylindrical vessel, lip formation by forging characterised in that before the lip formation, the material is further drawn from the body side of pressure cooker and to add at the lip to enhance density and strength of the said Up. 4, The novel pressure cooker with reinforced short lip as described in the description of the complete specification and as illustrated by way of figures 4,5 & 6.

Documents:

0158-mas-2001 abstract-duplicate.pdf

0158-mas-2001 abstract.pdf

0158-mas-2001 claims-duplicate.pdf

0158-mas-2001 claims.pdf

0158-mas-2001 correspondence-others.pdf

0158-mas-2001 correspondence-po.pdf

0158-mas-2001 description (complete)-duplicate.pdf

0158-mas-2001 description (complete).pdf

0158-mas-2001 drawings-duplicate.pdf

0158-mas-2001 drawings.pdf

0158-mas-2001 form-1.pdf

0158-mas-2001 form-19.pdf