DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0027] Referring initially to FIGS. 1 to 5 of the drawings, there is shown a first cooking appliance 10 embodying the invention, which comprises a rectangular box-like housing 100 , a generally semi-cylindrical stainless steel food receptacle 200 pivotable about a horizontal central axis X 1 , and a drive mechanism 300 for pivoting the receptacle 200 . The housing 100 has a main body 110 housing the food receptacle 200 and driving mechanism 300 , and includes a top lid 120 hinged at one end for closing the body 110 .

[0028] Also housed within the body 110 is a generally deep semi-cylindrical fixed aluminum pot 130 that has a rectangular top opening. The food receptacle 200 lies horizontally inside the pot 130 , together sharing a common horizontal central axis that coincides with the pivot axis X 1 . The drive mechanism 300 is located outside the pot 130 , at one end thereof.

[0029] The food receptacle 200 is a screen basket having a pair of generally semi-circular solid vertical end walls 210 and a generally shallow semi-cylindrical meshed or perforated base wall 220 . The base wall 220 extends horizontally at right angles across the end walls 210 and equidistantly round or about the pivot axis X 1 .

[0030] A rectangular rigid wire frame 230 connects across the tops of the end walls 210 for reinforcement or support, through which food articles, such as potato chips, can be loaded into the basket 200 . The basket 200 has a generally semi-circular cross-section that is flatter than that of the pot 130 , and a marginally smaller diameter for being held in the pot 130 as a rotational sliding fit about the pivot axis X 1 .

[0031] Both basket end walls 210 include respective upstanding apertured lugs 212 aligned with each other along the pivot axis X 1 . A pair of aligned hinges 214 and 216 support the basket 200 by its respective lugs 212 for pivotal movement about the axis X 1 in opposite directions, such that the basket 200 can rotate back-and-forth through an angle of about 70° on either side of the axis X 1 .

[0032] The drive mechanism 300 incorporates a bottom electric motor 310 driving a horizontal output worm gear 320 that is in mesh with an upward train of four double gearwheels 321 to 324 for speed reduction. The upper gearwheel 324 is fixed on a horizontal shaft 325 that includes an eccentric crank pin 326 . The second hinge 216 is a horizontal shaft fitted with a small gearwheel 218 . The drive mechanism 300 includes a third horizontal, middle shaft 330 immediately below the hinge shaft 216 , which is fitted with another small gearwheel 332 . The two gearwheels 218 and 332 are in mesh such that the hinge shaft 216 is rotatable by the middle shaft 330 . The middle shaft 330 includes an eccentric crank pin 334 .

[0033] A connecting rod 340 connects across the two crank pins 326 and 334 . While the first crank pin 326 is driven to turn in one direction by the motor 310 via the gear train 321 to 324 , etc., the rod 340 converts such a rotating action into angular reciprocation for the middle shaft 330 and in turn the hinge shaft 216 . Thus, the hinge shaft 216 turns in opposite directions to swing the food basket 200 back-and-forth inside the pot 130 , through an angle of about 70° on either side of the pivot axis X 1 .

[0034] The pot 130 serves to contain a relatively small amount (say 375 ml) of cooking liquid, such as edible oil, that submerges the lowermost space (as shown by dotted lines in FIG. 1 ) of the food basket 200 at any angular position thereof. An electrical heater 140 is installed right at the bottom of the pot 130 to heat up the oil (say to 200° C.) for cooking the potato chips.

[0035] The basket 200 includes, on the inner surface of its base wall 220 , a plurality of food traps formed by ridges 222 each having a triangular cross-section. The ridges 222 extend at right angles across the end walls 210 and are spaced apart angularly about the pivot axis X 1 . As part of the base wall 220 , the ridges 222 are likewise meshed or perforated. The ridges 222 are relatively short (in terms of height) and are separated to form co-parallel shallow recesses or channels 224 between them for temporarily trapping or retaining the potato chips.

[0036] During swinging of the food basket 200 , the potato chips are conveyed upwards on the rising side of the basket wall 220 . The chips at the top of the heap will gradually roll or slide (or fall) back down, while those at the bottom remain trapped in the channels 224 as retained by the ridges 222 . When the basket 200 swings to the uppermost position ( FIG. 1 or 4 ), most of those bottom chips previously entrapped will have brought up and then allowed to roll back down thereby becoming situated at the top of the heap. Thus, the chips at the bottom (being fried in the oil) are turned upwards to the top (out of the oil), and the same action takes place when the basket 200 swings in the opposite direction. The action repeats in cycle until all the potato chips are cooked.

[0037] The ridges 222 are made not too tall to ensure that all the potato chips that have been lifted can go back down. All the ridges 222 , especially those upper ones on either side that are more clearly so, have a generally triangular cross-section having opposite sides. The sides of upper ridges 222 ′ are inclined at a relatively larger angle to the basket base wall 220 than those of lower ridges 222 ″. The difference in gradient causes the potato chips to move down from different heights and/or at different times, thereby ensuring thorough agitation of the chips. In particular, the chips trapped by the upper ridges 222 ′ will be swung up to a higher level that is sufficient to allow them to turn over before falling down.

[0038] The traps, i.e. ridges 222 and channels 224 , are produced by bending the basket base wall 220 in a wavy manner. In a different construction, the traps may be provided by any other forms of protrusions, such as knobs, bosses or posts, fixed on the basket base wall 220 , which are spaced apart to create cavities therebetween for trapping or catching food articles.

[0039] It is envisaged that the bottom inner surface of the food basket 200 may be left empty (as a wider channel 224 ) or made flat so that the bottom food articles can move about freely without being jammed in place.

[0040] FIGS. 6 to 8 show a second cooking appliance 10 A embodying the invention, which has a construction similar to that of the first cooking appliance 10 , with equivalent parts designated by the same reference numerals suffixed by a letter “A”. The major differences lie in that the food basket 200 A has a generally cylindrical shape and that the drive mechanism 300 A is adapted to rotate the basket 200 A continuously in one direction.

[0041] The food basket 200 A is likewise a screen basket, having a pair of generally circular solid vertical end walls 210 A and a generally cylindrical meshed or perforated peripheral wall 220 A extending horizontally at right angles across the end walls 210 A. The cylindrical basket 200 A is supported centrally for rotation about the pivot axis X 1 for tumbling food articles, such as potato chips, contained therein.

[0042] The peripheral wall 220 A includes a hinged segment 230 A that is openable like a lid to allow food articles to be loaded into the basket 200 A. The wall 220 A is stamped into a wavy shape to form the ridges 222 A and channels 224 A before it is bent into a cylinder and then connected to the end walls 210 A to form the food basket 200 A.

[0043] The aluminum pot 130 A remains generally semi-cylindrical, having a diameter that is marginally larger than that of the basket 200 A for holding the basket 200 A partially (about half) therein as a rotational sliding fit about the pivot axis X 1 . The drive mechanism 300 A likewise incorporates an electric motor and a speed-reduction gearbox, for rotating the food basket 200 A slowly in either one direction.

[0044] In the case of both cooking appliances 10 and 10 A, as the food articles are to be turned and mixed by themselves without the use of any agitator, they can be kept intact without being broken into smaller pieces or squashed. Given that the food articles will be turned continuously, a relatively small amount of cooking liquid can be used, which by reason of its small quantity can be heated up to the required cooking temperature (200° c.) in a relatively short time (5 minutes).

[0045] The invention has been given by way of example only, and various other modifications and/or variations to the described embodiments may be made by persons skilled in the art without departing from the scope of the invention as specified in the accompanying claims.