This invention relates to Rotary engines and aims to provide a positive - displacement variable - volume device which will operate in the manner of a four cycle Rotary engine, and proposes a means of constructing a power unit which may be considered as a practical alternative to the well known conventional piston engine, which even with improvements to date and current auto trends towards high turbulance, and lean/clean burning engines, is still regarded as a thermo- dynamically inefficient means of converting fuel into energy, since any theoretical analysis of this engine type, in both diesel and petrol form, shows that at least 20 percent of the engine heat leaves with the exhaust gases, and a further 35 percent is lost to the cooling system. Of the remaining 45 percent, further energy losses are also incurred by the surging action of the gases as they are sucked into the engine, compressed, expanded and exhausted in quick jerky movements by the inefficient dynamic actions of the pistons, pins and connecting rods. These relatively heavy engine components are all subjected to violent reversals of direction at a frequency of four times per engine cycle, or 100 times per second per cylinder even at moderate engine speeds of 3000 revs per minute. Thus the achievements of modern Auto-Engines with regard to fuel efficiency (M.P.G.. ) and exhaust emissions may be considered the more remarkable when it is also taken into

account that this rapid processing of gases within the engine is accomplished by means of poppet-valves and mechanical operating gear, which all tend to command a disproportionately high degree of engineering design content, not to mention maintenance and repairs to chains, drive belts, etc., and whilst the conventional engine has undergone a long process of incremental refinement since its conception a century ago, its limitations are probably best highlighted by the widely held view of auto-engineers and theoretical researchers alike that the continued predominance in the automotive field of this relatively complicated and inefficient power unit can only be justified by the absence, hitherto, of a less costly and clean- burning Rotary alternative, though there certainly appears to have been no shortage of contenders - even as early as the turn of the century.

The Wankel Rotary Engine since its conception and early development at N.S.U. in the 1950's attempted to overcome some of the shortcomings of the conventional engine, and may have achieved more success, but for the increasingly stringent limits imposed world wide relating to Auto-Exhaust emissions for new vehicles. Whilst the emission levels on TOYO/KOGYO'S version of the AUDl/NSU/WANKEL have been reduced somewhat with the aid of a catalytic convertor, and are now claimed to compare favourably with conventional engined vehicles as also early problems with seal durability and low speed engine misfire - have both been largely elli inated - it is still generally considered that the high surface/volume ratio and crevice volumes which are formed in the acute wedge portions of the crescent shaped combustion chamber and also the inadequate

separation of the inlet and exhaust engine phases, are a combination which will probably form the limiting factor to further optimise the efficiency and exhaust emission levels within this type of Rotary engine. It is an aim of the present invention to provide a Rotating variable/volume device which may be constructed in the manner of a four cycle Rotary engine; in which gases may be admitted to, compressed, expanded and expelled from the engine in a continuous flowing motion, wherein clean burn potential is provided by the considerably low surface/volume aspect of the combustion spaces and in which four clearly defined engine phases are accomplished by the pumping actions of two rotating piston pairs as they are passed over inlet ports, ignition apperture, and exhaust ports incorporated within the circular or toroidal shaped housing. A Rotary engine of the present invention may be constructed for use with a variety of fuels, e.g. liquid gas, petroleum, diesel etc., and may be considered- particularly suitable for diesel operation since the concentric rotating action of the two piston pairs imposes no constraints on the theoretical upper compression ratio limits, and can easily accommodate the 16 or 20/1 requirement for diesel engine operation. The proposed invention also aims to provide a more compact and simplified prime mover than the conventional engine, whereby the construction and operation of which may be considerably less complicated by the total absence of valves, valving gear, multi-cylinder fuel management systems or distributor, and also wherein ignition means may be provided, or assisted by a glow plug or permanently heated element, this well known method for igniting gases may be considered

advantageous, since it is an inherant feature of the proposed invention that the inducted gas charge is not caused to be in contact with the igniting media, i.e. spark plug, fuel injector, glow plug, etc. until or near the point of maximum compression of T.D.C. Accordingly, the present invention provides a four cycle rotary piston engine in which a total of four piston members are mounted for concentric rotation within a circular or toroidal shaped stationary housing, the four pistons are each secured to or may be formed integral with two rotatable piston hubs, and each piston pair are arranged on and secured to diametrically opposite sides of each hub at angular intervals of 180 degrees, forming thus a rotor assembly.

The described rotor assembly consisting of four pistons which are arranged in pairs and secured to two piston hubs are all caused during rotation of the engine to move in a circular direction, but each hub with attached pair of pistons are caused to be rotated at constantly varying speeds, and are alternately speeded up and slowed down every 90 degrees of engine rotation, in a manner whereby as one pair of pistons are caused to be moved slowly through the vertical axis of the engine, the adjacent hub and piston pair are simultaneously caused to move rapidly through the horizontal axis of the engine. The combined action of these two piston pairs rotating at constantly varying relative speeds, having an effect whereby each pair of pistons are caused to catch up with the preceding pair at both the upper and lower halves of the vertical axis of the engine simultaneously every 90 degrees of engine rotation, in a manner whereby gas is compressed to its minimum volume at T.D.C. or zero degrees within the chamber which is formed

between the pistons crowns at the top or upper half of the vertical axis, whilst the chamber which is formed between the pistons at the lower half of the vertical axis at 180 degrees therefrom, is simultaneously emptied of gases and ready to move into the induction phase of the engine cycle. At this same moment the induction and expansion chambers which are formed on the horizontal axis are both fully expanded and are also ready to progress into the next sequential engine phase, i.e. induction - compression and expansion - exhaust. Thus it will be seen that all four engine cycles of induction compression, expansion and exhaust, will change over, occur and progress on all four chambers simultaneously at regular 90 degree intervals of engine rotation. The previously described action of piston pairs which are constantly and alternately accelerating and decelerating in a rotating scissor action type of movement is accomplished by the provision of piston phasing components, and comprise of an engine mainshaft which is located at and ex'tended throughout the axis of the engine and onto which is firmly secured two crankshaft carrier hubs, one at each axial side of the engine housing. A plurality of crankshafts are mounted for rotation within each of the carrier hubs, and each of the crankshafts are provided with an epicyclic or orbital gear, which are each secured to, or may be formed integral, with the crankshafts. Each of the two crankshaft carrier hubs are in close proximity to a stationary gear, which are both firmly secured to the engine casing, and are provided with gear teeth which are twice in number, and for engagement with the gear teeth of the orbital gears, whereby in operation of the engine, as the mainshaft and carrier hubs are caused to be rotated

through ->ό0 degrees, the orbital gears and crankshafts will be rotated twice - or 720 degrees within each of the two carrier hubs. Each of the crankshafts within the carrier hubs are also provided with an eccentric journal portion and to which each of the two piston hubs is connected. The piston hubs may be connected to the crankshaft journals by various means, e.g. slotted thrust plates, etc., but a preferred embodiment would have connecting rods in a similar manner to the conrods within a conventional engine, and the conrods which may be of unit or modular construction would be connected from the plurality of crankshaft journals to each of the two thrust plates which are each firmly secured to the extending outer axial portions of the two pistons hubs. This described assemblage of piston phasing componants having a combined effect whereby in operation of the engine, the engine mainshaft, crankshafts and carrier hubs will all be caused to rotate about the engine axis at a uniform cyclic velocity; whilst in contrast, the rotational velocity of pistons, piston hubs and thrust plates will be caused by the action of the eccentric crankshaft journals and conrods to accelerate and decelerate simultaneously in a scissor action type of movement every '90 degrees of engine rotation, and thus power which is created by gases expanding progressively within the four chambers which are -each defined by two piston faces - two piston hubs - and stationary housing is transferred in a split-path to each end-or outer axial portion of the engine mainshaft, this tortional energy is transmitted at regular 90 degree intervals passing from the piston pairs via the two piston hubs, thrust plates, connecting rods and crankshafts, and is reflected into the crankshaft

carrier ._αbs by the orbital gears reacting upon the two stationary gears. Gases are admitted to and expelled from the engine via induction ports which are provided in the engine housing at a point adjacent to and extending either side from the lower half of the vertical axis, or at a point approximately 180 degrees from the engine ignition apperture at zero degrees. Sealing means are also provided between sliding surfaces as and where required, for the containment and separation of gases and liquids and in this respect it is an advantageous feature of the proposed concept that the primary sealing faces of all sealing elements are maintained in a constant and unvarying angular attitude with all corresponding sliding surfaces. The engine will now be described with reference to the accompanying drawings in which:- Fig 1: is a diagramatic sectional view of a preferred embodiment of the engine having pistons of a circular profile, mounted for rotation within a toroidal shaped cylinder or housing and is viewed parallel to the axis.

Fig 2; is a diagramatic axial view of Fig 1, viewed at right angles and sectioned through the centre of the engine.

Fig 3; is a simplified diagramatic view in which the basic phasing principle is demonstrated by the substitution of connecting rods and wherein the piston hubs are connected to the crankshafts by means of slotted thrust plates. Fig 4; is a diagramatic perspective view demonstrating the construction of a rotor assembly having rectangular shaped pistons. Pistons having a similar profile are also shown in Figs. 30 and 31. Figs 5 - 10; are a diagramatic series, in which the engine

mainshaft is rotated through a total of 112.5 degrees from the engine firing position at zero degrees and demonstrates the various engine phases as they progress and occur within each of the four chambers at 22.5 degree intervals, in which the piston hub (HB) is not shown or denoted and symbols are used to explain the engine phases, which are explained in Fig 37. Figs 11 — 16: are a scematic series, in which the mainshaft is rotated through 112.5 degrees at intervals of 22.5 degrees and in which both the phasing principle, and the actions of the pistons relative to the crankshafts and mainshaft is demonstrated more advantageously by viewing both crankshaft carriers as one theoretical single hub and in which the piston movements are regulated by an alternative means than connecting rods, wherein the pistons are controlled by thrust plates which are provided with slots which are- engaged onto the eccentric ^* crankshaft journals.

Figs 17 — 22; are a diagramatic series, in which the mainshaft is rotated through 112.5 degrees at intervals of 22.5 degrees and in which phasing componants are hypothetically arranged to demonstrate more advantageously the relative angular positions of pistons, crankshafts, conrods, hubs and mainshaft, and also in which the scissor-type action of the thrust plates (TP) with pistons attached, is demonstrated in contrast to the uniform cyclic rotation of the engine mainshaft, which is denoted by a dark triangle.

Figs 23 — 26; are a simplified diagramatic series demonstrating the progressive construction of a rotor assembly into an engine housing, with pistons having a circular -profile and in which are shown 4 pistons, 2 piston hubs and a two-piece engine

housiny and is similar in construction to the preferred embodiment in Figs 1 and 2.

Fig 27; is a diagramatic view of Fig 26, viewed at right angles and sectioned through the engine centre line and is also similar to the series of Figs 5 - 10.

Fig 28; is a diagramatic view of an alternative piston shape which may be employed in the construction of an engine of the present invention and shows four rectangular pistons which are arranged for diagonal mounting in pairs onto two piston hubs. Fig 29: is a diagramatic view of components from Fig 28 assembled into a two-piece engine housing.

Fig 30; is a similar configuration to Fig 4 and is a diagramatic view of a further alternative piston shape which may be employed in the construction of an engine and shows four pistons which are arranged for mounting onto two piston hubs.

Fig 31; is a diagramatic view of components from Fig. 30 assembled into a three-piece engine housing.

Fig 32: is a diagramatic view of two crankshaft carrier hubs which are mounted onto an engine mainshaft, and demonstrates a method by which the two crankshaft carrier hubs may be firmly secured to an engine mainshaft of the present invention and in which is shown a split or slotted tapered sleeve which may be compressed onto the mainshaft and is secured to the carrier hub by bolts or screws. The hubs are also positively located and further secured to the mainshaft by means of keys, though other well known means may be employed, e.g. splines, machined facets, etc.

Fig 33: is a diagramatic view of two crankshaft carrier hubs, which are mounted onto an engine mainshaft and demonstrates an

alternative means by which the two crankshaft carrier hubs may be firmly secured to an engine mainshaft, and in which one hub is welded to the mainshaft and the other is secured and located by means of spring pins or dowels and screws. Fig 34 — 36; are a diagramatic series in which both crankshaft carrier hubs are shown to rotate simultaneously through 90 degrees from the firing poistion of T.D.C. at intervals of 45 degrees, and in which can be seen the actions and related positions of the piston phasing components during rotation of the engine.

Fig 37; is a schematic 360 degree diagram and demonstrates the approximate duration of the four engine phases and the relative angular movements of the leading (L) and trailing (T) edges of the piston crowns throughout each of the engine phases and wherein is also shown both the angular and radial geometry which may be employed in the construction of a preferred embodiment of the proposed engine, and in which the selected or chosen angular deflection of each hub and piston pair in this example is 34 degrees per each 90 rotation of the engine mainshaft; thus providing a piston stroke of 68 degrees. It will be appreciated, however, than an engine of the proposed concept may be designed for construction having a piston stroke or deflection which may be greater, or lesser, than 45° x 2 and 34° x 2 examples given within the enclosed drawings, e.g. 30° x 2 , 36° x 2, etc., and would importantly require provision for, and correct geometrical location of the engine phasing componants, and accordingly in Fig 37 is provided an example wherein is shown two piston pairs (A and C), (B and D) in an engine which is at T.D.C. or minimum volume within chambers

(A-B) ana (C-D) and the piston centre lines A-C, B-D are at an angular displacement of 56° or 28° either side - from the vertical axis (UVA) and (LVA) . The piston pairs (A-C) are connected at a radial distance of RI via connecting rods (CR) to the eccentric journals (E) of the two crankshafts (CS) which are both positioned on and coincide with the horizontal axis (HAX) and at a radial distance of R2 from the engine axis. Pistons B and D are similarly connected to the crankshafts which are positioned on the vertical axis (UVA-LVA) and the angular values, radial dimensions and connecting rods centres are given thus:- Angles X and Y = 73° = 90° - (34° divided by 2) Angle Z = 62° = (45° + 17°) Radius of Link pin centre (RI) = R2 divided by 1.4142 divided by cosine of 17°

Radius of crankshaft centres (R2) = distance between connecting rod centres (CR) x 1.4142.

Radius of crankshaft journal eccentric (R3) = RI x sine of 17°. Distance between connecting rod centres (CR) = RI x cosine of 17°.

Whilst the described angular and radial locations of the crankshaft centres (R2) and the piston centre lines (A-C) (B and D) in Fig 37 during rotation of the engine wi l effect an average angular relationship of 45° between each piston pair and their respective crankshafts - which are housed at axialy opposite sides of the engine centre line, it will be appreciated that alternative embodiments of the engine may be constructed having conrods which are longer or shorter than the example given in Fig 37, and accordingly the crankshaft centres may be

reϊocat in a 45° direction - relative to the horizontal axis (HAX) and the radial distance of the crankshaft centres R2 from the engine axis will be equal to the square root of:-(RI x cosine of 17° squared) plus (distance between conrod centres (CR) squared) , and the radius pitch of the orbital and stationary gears will be respectively R2 divided by 3 and R2 divided by 1.5, plus or minus tolerances for engine operation. Whilst only two crankshafts.per piston pair are demonstrated in Fig 37, it will be appreciated that the optimum ratio of crankshafts per piston pair can be optional, and this ratio will be determined more by the aspect ratio of engine durability - production costs and frictional factors, etc. as also will be the gear type, e.g. spur gears, hellical, double hellical, or bevel type gearing. Fig 38: is a diagramatic view of an alternative method by which the pistons could be connected to the crankshafts. Fig 39: .is a diagramatic view of a further alternative method by which the pistons may be connected to the crankshafts . Referring now to the drawings Figs 1,2 and 3 and in particular to Figs 1 and 2 wherein is shown a preferred embodiment of the present invention and in which a rotor assembly consisting of four pistons (A), (B), (C) and (D) are each secured by means of tapered studs (S) to two piston hubs (HA) and (HB) . Pistons (A) and (C) are secured to hub (HA) and pistons (B) and (D) are secured to hub (HB) . The described rotor assembly is mounted for rotation within a two-piece engine housing (H) which is provided with an induction port (IP) and an exhaust port (EP) which are both adjacent to and extending either side from the lower portion of the vertical axis of the engine, or

approx__.dtely 180 degrees from the upper portion of the vertical axis wherein is provided an ignition aperture (SP). Gases and fluids are controlled or contained within the engine by the provision of sealing elements or rings (SR) in a similar manner to the well known methods used in a conventional engine. Four discrete variable volume gas chambers are formed between each of the pistons (A), (B), (C) and (D), the housing (H) and the piston hubs (HA) and (HB), and during rotation of the engine, all four chambers are caused to be continuously and simultaneously expanded and contracted by the rotating actions of the two piston pairs (A) and (C), (B) and (D), which are both caused to rotate within the housing at constantly varying relative speeds, in a manner whereby, as any two diametrically opposite chambers are passed simultaneously through the upper and lower vertical axis of the engine, they will be at their minimum volume, whilst at the same moment of time, any two chambers which are passing _^ through the horizontal axis will be at their maximum volume.

The described action of pistons (A),(B),(C) and (D) rotating in pairs on hubs (HA) and (HB) at constantly differing relative velocities, is accomplished by the combined action of the piston phasing components, which comprise an engine mainshaft (MS) situated at and extending throughout the engine axis, and onto which are firmly secured two crankshaft carrier hubs (CA) and (CB) one at each axial side of the engine housing (H) and into which are mounted a plurality of rotatable crankshaft (CS) which are each provided with and firmly secured to a planetry or orbital gear (OG) and each of the two stationary gears are provided with gear teeth which are twice in number to the gear

teeth or each orbital gear (OG) , whereby in rotation of the engine, the plurality of crankshafts (CS) will be caused to rotate twice about their own axis or 720 degrees within each of the carrier hubs (CA) and (CB) per each 360 degree rotation of the engine mainshaft (MS).

Whilst the crankshafts (CS) are caused by the action of the orbital (OG) and two stationary gears (SG) to rotate within the carrier hubs (CA) and (CB), the journal portions (E) of the crankshaft (CS) are each connected by means of connecting rods or conrods (CR) to two piston thrust plates (TP) by means of gudgeon pins (P) . The two piston thrust plates (TP) are each firmly secured to projecting outer axial portions of the two piston hubs (HA) and (HB) by means of retaining nuts (N) . By way of the herein described connection between the piston pairs (A and C) (B and D) via the plurality of geared crankshafts (CS) all mounted for rotation within each of the two carrier hubs (CA) and (CB) which are both firmly connected via the mainshaft (MS), it will be seen that as the engine mainshaft (MS) is rotated at a uniform cyclic velocity, the piston pairs (A and C) (B and D) and attached piston hubs (HA) and (HB) will be caused alternately and simultaneously to be speeded up and slowed down relative to both the engine mainshaft (MS) and each other (A and C) (B and D) in a scissor action type of movement and wherein the piston stroke may be regarded as being equal to the sum of the total angular deflection of each piston pair - relative to the mainshaft - per 90 degrees of engine rotation. The operation of the engine will now be described with reference to the drawings and in particular to Figs 5-10 which are a simplified progressive series in an embodiment of the engine

having a piston stroke or deflection of 45 degrees x 2 or 90 degrees and in which is shown a rotor assembly comprising four pistons (A),(B),(C), and (D) secured in pairs to hubs (HA) and (HB), and are mounted for rotation within an engine housing (H) which is provided with an induction port (IP) and an exhaust port (EP) which are adjacent to and extend either .side from the lower portion of the vertical axis, and approximately 180 degrees from the point of engine ignition, which in Figs 5 and 9 is denoted by a Z shaped symbol. Symbols are also used to denote the four engine cycles and are explained in Fig 37. The engine mainshaft (MS) is also shown at the axis of the engine, and it's angular displacement from the engine firing position at zero degrees throughout the various engine cycles is indicated by a dark- triangle, as are also Figs 11-16 and Figs 17-22.

_* Referring now to Fig 5 in which is shown four pistons (A), (B), (C) and (D) which are arranged in diametrically opposite pairs (A and C) (B and D) and are secured to two piston hubs (HA) and (HB) - (although hub (HB) is now shown in Figs 5-10), four discrete variable volume chambers are formed and defined by the pistons (A,B,C and D), the engine housing (H) and the piston hubs (HA) and (HB), and from which it will be seen by the symbols - with reference to Fig 37 that chamber A - B is at it's maximum point of compression and is passing'- hrough the upper vertical axis and in which the gases are igniting at the commencement of the power cycle. Chamber B - C on the horizontal axis meanwhile is seen to be fully expanded, and is at the end of it's exhaust cycle. Chamber D - A on the horizontal axis is fully expanded, having completed it's induction cycle. Moving on to Fig 6 in which the engine mainshaft (MS) has

rotated chrough 22.5 degrees it will be seen that chamber A - B is partially expanded, and is imparting power to the pistons (A) and (B) . Chamber B - C is partially contracted and is expelling exhaust gases into the exhaust port (EP) . Chamber C - D has partially expanded, and is drawing in gases from the induction port (IP) and chamber D - A is partially contracted and is compressing the gases contained within. Moving on to Fig 7 in which the engine mainshaft (MS) has rotated a further 22.5 degrees, and has now completed a total angular displacement of 45 degrees from the engine firing position at zero degrees, and wherein it can be seen that all four chambers A-B, B-C, C-D and D-A have each progressed in their individual phases respectively expansion, exhaust, induction and compression from the previously described actions of Fig 6. This sequence continues on through Fig 8 until Fig 9 when the engine mainshaft has rotated through a total of 90 degrees displacement from the firing position of zero degrees, when chamber D - A is fully compressed at the upper vertical axis, and the engine now commences firing on chamber D - A. thus it will be seen in Fig 9 that all the previously described phases which were occurring within chambers A-B, B-C, C-D and D- A, throughout Figs 5, 6, 7, and 8 are all changing over simultaneously in Fig 9 to the next engine cycle,- i.e. expansion to exhaust, exhaust to induction etc. These phases will prevail within each of these individual chambers until the mainshaft (MS) has completed a further 90 degree rotation from Fig 9 when ignition will now commence in chamber C-D and the engine cycles within the other three chambers will change over as previously described. Thus, it will be seen that ignition

will occur on the engine every 90 degrees of mainshaft rotation, and that all chambers A-B, B-C, C-D and D-A will be caused to move into the next engine cycle simultaneously every time two pairs of adjacent pistons are passed through the vertical axis. Referring now to Fig 1, wherein is shown two crankshaft carrier hubs (CA) and(CB) which are each firmly secured to and located on the mainshaft (MS) aided by means of a Woodruff Key (K) . This simple arrangement in actual practice may be considered inadequate both in respect of the constantly alternating torsional loads which would be imposed on these components

(CA), (CB) and (MS) during engine operation, and also from a constructional viewpoint since it may be advantageous for at least one carrier hub (CA) or (CB) to be removable in respect of engine maintenance. Accordingly, therefore, a preferred embodiment may incorporate at least one or more removable carrier hubs (CA) or(CB) and one such example is shown in Fig 32, wherein is shown two carrier hubs (CA) and (CB) which are each firmly secured to the engine mainshaft (MS) by means of a tapered sleeve (TS) of unit or modular construction which may be drawn into the inner tapered portion of the hub during assembly by means of screws (S) or other means, single nut etc. Fixture and angular location of the hubs (CA) and (CB) may be further assisted by means of one or more keys (K), splines, circlips, etc. An alternative method of securing the crankshaft carrier hubs (CA) and (CB) to the engine mainshaft (MS) is shown in Fig 33 wherein the construction of an engine may be considerably simplified by securing at least one hub (CA) onto the mainshaft (MS) by welding means (W) , whilst the opposite hub (CB) may be

secure .jin in an axial and angular direction by a combination of dowels or spring pins (DP) and screws (S) which may be inserted between the outer and inner diameters of the mainshaft (MS) and hub (CB) . Whilst the pistons (A),(B),(C) and (D) on all embodiments of the engine are formed for rotation within a circular shaped housing (H), the profile of the pistons (A,B,C and D) and housing (H) when viewed at 90 degrees to the engine axis as in Fig 1, may be constructed having alternative profile forms, but a preferred embodiment of the engine as per the examples in Fig 1 and Figs 23-26, would be constructed having circular or toroidal shaped pistons (A,B,C and D), and the gas sealing rings (SR) on these pistons would be similar to the piston rings in a conventional engine, and the primary sealing contact area of the rings (SR) would be maintained constantly parallel to the engine chamber surface at all times. Alternative embodiments of the engine may incorporate pistons of a more rectangular profile, and an example is given in Fig 28 wherein is shown four pistons (A),(B),(C) and (D) which are arranged in pairs for diagonal mounting onto two piston hubs (HA) and (HB) and which in Fig 29 are assembled into a two piece engine housing (H) . A further alternative piston profile is illustrated in Fig 4, wherein is shown a perspective view of the construction of a rotor assembly comprising four pistons (A),(B),(C) and (D), which are.secured in pairs to or formed integral with two piston hubs (HA) and (HB) and are ready for mounting into a housing (H) .

With reference now to Figs 1 and 2, wherein the pistons (A,B,C and D) are shown to be secured to the hubs (HA and HB) by means

of stuu (S), and the orbital gears are each firmly secured to the crankshafts by means of keys, etc., it will be appreciated that a plurality of these components may more easily or conveniently be welded to, or formed as an integral part of another component, for example. The pistons (A),(B),(C) and

(D) may be formed integral with their respective hubs (HA) and (HB) , as may be the hubs (HA) and (HB) with the thrust plates, and also the crankshafts (CS) may be formed integral with, or welded to the orbital gears (OG) etc. Alternative methods may be employed for linking the crankshafts (CS) to the thrust plates, as in Fig 38 for example, wherein is shown a thrust plate (TP) which is connected to three conrods (CR) for oscillating movement by gudgeon pins (P) . The opposite or outer ends of the three conrods(CR) are each connected to an intermediate link (IL) by a link pin (LP) and the three intermediate links (IL) are each mounted for rotation on to at least two eccentric crankshaft journals (E) and in which the crankshafts (CS) are synchronised for rotation accordingly. This described arrangement is envisaged as a convenient means by which the crankshaft journal loading may be more evenly distributed. A further alternative example by means of which the thrust plates (TP) may be connected to the crankshafts, is given in Fig 39 wherein the thrust plate (TP) is 'provided with two thrust blocks (TB) which are each secured to the thrust plate (TP) by pins (P). Two slotted plates (SP) are mounted for rotation onto at least two each synchronised escentric journals (E) and in operation of the engine the thrust blocks (TB) will be caused to slide within the slots (S) of the slotted plates (SP) .

A rotary engine of the proposed design may more easily be assimilated with or equated to the well established conventional engine by regarding the proposed concept as a means by which the conventional crankshaft, conrods and pistons may be condensed into a fraction of the space and in which the valves, valve operating components and distributor, or in the case of a diesel, expensive multi cyl. fuel pump, are totally unnecessary. The resulting swept volume - engine mass ratio potential - can be further obviated by simply calculating that if an engine of the proposed design were constructed to the approximate scale dimensions of the example given in Fig 1 and in which all the dimensions are multiplied by a factor of 2.9, it would measure:-

Outside Dia. 31 cm. 12'.25 ins. Length 43 cm. 17 ins.

Piston Dia. 9.394 cm. 3.7 ins. Torus Dia. 16.104 cm. 6.34 ins. and with a piston stroke of = 45° x 2. This would provide an engine with a displacement of approximately 3500 cubic centimetres, or the equivalent power potential of the well known Rover Buick V8 engine and by way of comparison, whilst both engines would generate a power cycle every 90 degrees of engine rotation, the power rating of the conventional four stroke engine is calculated per two engine revolutions or 720 degrees, whilst a rotary engine of the proposed design will complete all four cycles on all four chambers in only 360 degrees. Even temperature distribution of the engine may be ^' controlled by passing fluids through galarys (G) formed within the engine housing (H) and with regard to adequate separation

or coo_...c r u s rom com us on pro ucts, may oe cons ere advantageous for the fluid galarys (G) of the two piece engine housing (H) in Fig 1 to be conduitly connected at a point which is adequately distanced from the high pressure area of the engine. Such an example is given in Fig 2 where galarys

(G)emerge from the housing (H) at a point adjacent to the inlet port (IP) and the exhaust port (EP) . Cooling of the engine oil may also be effected or assisted by means of its convenient proximity to galarys (G) at the outer axial portions of the housing (H) . Oil may be stored within the engine and passed via the pick up point (PU) to the oil pump (OP) wherefrom oil may be pressure fed to all or any parts of the engine and distributed by way of the oil galary (GA) formed within the engine mainshaft. * The herein described invention may also be adapted for the pumping, metering, or control of fluids of gases by providing at least two inlet ports and two exhaust ports within the engine housing.