5. Device of Claim 2 or 4 wherein position of said container (17) is at focal point of said mirror.

6. Device of Claim 1 wherein position of said mirror (14,46) is manually manipulated by means of rolling on said spherical ball (16).

7. Device of Claim 1 wherein said receptacle 41 is formed within cups (34, 35), said cups clamped together by means of bolt and nut fixture (37,36). Device of Claim 1 wherein said container (17) is placed on plate (11). Device of Claiml wherein said ball (16) and cups (34,35) ride on base (18). Device of Claim 1 wherein said ball (16) and cups (34,35) ride on base (18) said base (18) rides on telescopic structure (22-28).

11. Device of Claim 1 wherein said ball (16) and cups (34,35) ride on base (18) said base (18) slides on a rod (53), said rod jutting out from a wall (33).

The following specification describes the nature of this invention:
FIELD OF INVENTION
The present invention is in the field of cooking and heating devices. More
specifically the invention relates to cooking and heating by means of solar energy.
BACKGROUND - PRIOR ART AND NEED OF THE INVENTION
Paucity of fuel such as low pressure gas has made it necessary to seek alternative sources of heat energy for cooking food or heating water and the like. Domestic cooking by means of solar energy is well known, but it is not much in use. One reason for its little use is that the sun's position in the sky keeps changing continuously but the solar cooker points in a fixed direction. Full heat of the sun is received in the solar cooker only when the sun is directly pointing towards the cooker, and as the earth rotates onwards the sun's rays largely miss the cooker, so that the cooking is not completed satisfactorily.
Another reason for very little use of solar energy for domestic cooking and heating is that urban houses and apartments, and also tightly populated rural dwellings, do not have approachable roofs or courtyards where the solar cooker may be placed for receiving enough of the sun's rays for proper cooking or boiling water. Apartments in high rise buildings are commonly envisaged with balconies one above the other, and sun's rays that may be adequate for cooking do not fall into the balcony space.
It is desirable that the position of the cooker be conveniently changed so as to point towards the sun as the sun moves in the sky.
Positioning of the solar cooker and /or heater of the present invention is easily manageable manually so as to point towards the sun and thereby maximize the receipt of solar energy for domestic cooking and heating.
OBJECT AND ADVANTAGES
Object of the present invention is to provide a convenient means to adjust the position of domestic solar cooker so as to receive maximum energy from the sun.
Disadvantages in the solar cookers hitherto have been that:
The cooker points in a fixed direction, and receives solar energy fully only when sun is directly over the cooker.
It is not convenient to move the cooker into positions facing the sun as the sun moves across the sky.
Balcony spaces commonly available in apartments in high rise residential buildings do not receive solar rays adequately for satisfactory cooking.
Advantage of the device of present invention is that it makes it convenient to move and point the cooker towards the sun in the domestic setting, so as to efficiently capture the vast and free solar energy in a practical manner.
DRAWING FIGURES
In the accompanying drawing figures device of the invention has been illustrated by way of a non-limiting example.
Figure 1 shows schematically in sectional view a preferred embodiment of device according to the present invention.
Figure 2 shows external front elevation view of device of Figure 1.
Figure 3 shows external rear view of the device of Figure 1.
Figure 4 shows external end view of an extendible mounting structure for the device of Figure 1.
Figure 5 shows external end view of a sliding rod mounting for the device of Figure 1.
Figure 6 shows sectional view of rod and pedestal of Figure 5.
Figure 7 shows in sectional view details of ball and socket of the device of Figure 1.
Figure 8 shows schematically in sectional view a mounting according to the present invention of flat mirror type cooker.
REFERENCE NUMERALS IN DRAWINGS
Hotplate
Stem
Concave Mirror base
Concave Mirror
15 Leg
16 Ball
17 Food or drink container
18 Base
19 Floor
21 Head
22 1st Folding member
2nd Folding member
3rd Folding member
4th Folding member
5th Folding member
27 6th Folding member
28 Bottom binge
29 Rear frame
31 Screw
32 Upper Screw
Wall
Lower cup
Upper cup
Nut
37 Bolt
Upper Bore
Bore

Receptacle
Black
Chamber
Glass
Box
Flat mirror
Mirror hinge
Glass hinge
Flat mirror base

Pedestal
Groove
Rod
Lever
Handle
DESCRIPTION
In cited example 20 cm. wide x 20 cm. long x 10 cm. high food box 17 made
of 1 mm thick AISI304 grade stainless steel sheet is placed on 5 mm thick cast stainless steel hot plate 11 riveted underneath to stainless steel stem 12 riveted to edge of concave mirror base 13. Inner concave face of 13 is concave mirror 14 of diameter 80 cm. and focal length 60 cm.. Centre point of base of hot plate 11 is located at focal point of mirror 14. Handle 55 is affixed on rear of 13.
Base 13 is screwed on upper end of leg 15 and the lower end of leg 15 is welded to ride spherical ball 16 made of ball bearing grade polished steel 40 mm in diameter. Ball 16 rolls smoothly in fitting and enclosing hemispherical cup shaped receptacle 41. Receptacle 41 is formed between upper cup 35 and lower cup 34. Cups 34 and 35 are held together by means of bolt 37 passing through upper bore 38 in upper cup 35 and bore 39 in lower cup 34 said bolt 37 tightened by means of nut 36 so as to clamp, retain and tightly hold in place ball 16 within receptacle 41. Lower cup is welded underneath to base 18 firmly affixed in the device of Figure 1 to floor 19 on roof of the building or in courtyard of the building in which cooking is required to be carried out so as to get full exposure to sun over the whole year, but, as variation, on to head 21 of Figure 4 or to pedestal 51 in Figures 5 and 6. Receptacle 41 is greased and tight on ball 16.
In case of a building that does not afford a roof nor courtyard but only
has a balcony exposure to sun's rays the assembly of mirror 13 and food box 17 depicted in Figures 1,2 and 3 is fixed on base 18 to head 21 of a telescoping structure of Figure 4, the structure leveraging on members 22,23,24,25,26, and 27 tightly held on bottom hinge 28 on rear frame 29 which is firmly affixed to exposed outer face of wall 33 near a balcony of the residential apartment by means of screws 31,32 , said structure being manually stretched out by pushing handle 55 sufficiently so as to catch as much of the sun's rays as possible. A variation of the mounting arrangement depicted in Figure 4 for the device of Figures 1,2 and 3 is presented in Figure 5, comprising stainless steel rod 53 of diameter 20 mm jutting out horizontally from and grouted in exposed outer face of wall 33 at balcony of the building, crosssection,with groves 52, of rod 53 being as depicted in Figure 6. Pedestal 51 slides back and forth snugly on rod 53 and its position can be fixed on the latter at any desired point by means of tightening screw lever 54. Base 18 of device of figure 1 is here screwed on top of pedestal 51. Details of the ball 16 rolling in smooth spherical receptacle 41 formed within the enclosing cups 34 and 35 are depicted in Figure 7. A lower cost solar cooker is presented in Figure 8, comprising a simple flat mirror 46 mounted on flat base 49 hinging at 47 to rectangular box 45. Inside surfaces of box 45 are coated with heat withstanding black paint 42 and upper face of box 45 is shut by a 2mm thick glass cover 44 hinged at 48 to outer upper edge of box 45, thereby forming a chamber 43. On bottom of chamber 43 is placed the food box 17. Box 45 rides on leg 15 swivelling on ball 16 as in Figure 1. Mountings of the entire cooker assembly of Figure 8 on its base 18 are as in case of the device presented in Figurel, i.e., similar to Figures 4, 5, 6 and 7, so as to get maximum solar energy on all days on reflection from the flat mirror 46 of size 30cm x 30 cm. on box 17, manipulated through handle 55 in the present example for the directions of incident and reflected solar rays as shown in Figure 8.
OPERATION
After the sun has risen in the sky food is placed in cleaned box 17 and box 17 placed on hot plate 11 of Figure 1 or in chamber 43 of Figure 8. In case of mounting arrangements of Figure 4 or 5, the cooker is pushedrotitwards from balcony of the apartment towards the sun's rays. As sun moves across the sky, the mirror in respective case is pushed manually so as to roll on ball 16 and face
towards the sun's rays as far as is practically possible, to derive maximum benefit of free solar power, manipulated by means of the handle 55.
As food box 17 and parts of the cooker are hot, padded heat gloves are put on hands of the operator for placing, examining and removing box 17. After the food is cooked box 17 is removed and mirror 13 or 46 can be rotated out of position, to restrain undue heating, and for cleaning and wiping the device.
CONCLUSIONS, SCOPE AND RAMIFICATIONS
The reader will see that the device of this invention puts the free and vast solar energy within easy reach of domestic kitchens. This advantage is even more significant due to the constanly rising cost and limited availability of low pressure gas. Moreover, it is accepted that the nutrients in food are well retained in case of solar cooking in enclosed box 17 or in a pressure cooker that could be used here in lieu of the lidded box 17. The cooking by solar means is gentle in comparison with the intense heat of fuel flame of low pressure gas burner or electric heater or induction type heater or microwave oven. The taste of food cooked in gentle solar heat of the thick hot plate 11 has a special tang.
The hot plate 11 is good for making chapattis or dosa as well, specially on the concave mirror type cooker of Figure 1, but it requires a longish clamp and skill for manipulating on the hot surface. Steam vessel for idlis can be placed on hot plate 11 too, so too containers for baking of dishes or for heating or for boiling water for tea or coffee. Intensity and quantity of solar heat on plate 11 can be attenuated at any time during cooking by manipulating the angle of the cooker relative to direction of rays of the sun through pushing or pulling on the handle 55 as may be desired by a chef or connoisseur.
The equipment of this invention is simple and can be manufactured at low cost indigenously. The running and maintenance costs are negligible which mean a very appreciable relief for households. Danger of fires is absent or low. However it has to be aesthetically acceptable to mount the devices of Figures 4 and 5 on or near balconies of modern high rise apartments. The manipulating of the device of this invention all the time to face the sun requires attention of the cook every 15 to 30 minutes, i.e., twice for every dish if its cooking time extends to about one hour. Manipulating the device and placing and removing the cooking vessel on plate 11 also requires a new skill, though it should not be difficult to learn. Over heating of the dish has to be guarded against too.

CLAIMS I claim:
A device for cooking by means of solar heat comprising a food or drink container (17) facing a mirror (14,46) wherein said mirror (14,46) rides on a spherical ball (16) said ball (16) tightly rolling in a spherical receptacle (41).
Device of Claim 1 wherein said mirror (14) is concave shaped.
Device of Claim 1 wherein said mirror (46) is fiat shaped.
Device of Claim 1 wherein said mirror (14) is parabolic in shape.
5. Device of Claim 2 or 4 wherein position of said container (17) is at
focal point of said mirror.
6. Device of Claim 1 wherein position of said mirror (14,46) is manually manipulated by means of rolling on said spherical ball (16).
7. Device of Claim 1 wherein said receptacle 41 is formed within cups (34,
35), said cups clamped together by means of bolt and nut fixture
(37,36).
Device of Claim 1 wherein said container (17) is placed on plate (11).
Device of Claiml wherein said ball (16) and cups (34,35) ride on base (18).
Device of Claim 1 wherein said ball (16) and cups (34,35) ride on base (18) said base (18) rides on telescopic structure (22-28).
11. Device of Claim 1 wherein said ball (16) and cups (34,35) ride on base (18) said base (18) slides on a rod (53), said rod jutting out from a wall (33).