AU5187200A - Coupling arrangement for reciprocating piston engine - Google Patents

Description

I. AU6. 2000 18:40 FREEHILLS MELB 5. 613 392881567 FREEHILLS MELB 5 -1I- NO. 1323 P. 89 P100/00 I1 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Namne of Applicant: Actual Inventor: Address for service in Australia: Invention Title: Claude Neil BRESLAND As Above FreehiL Caner Smith Beadle 101 Collins Street Melbourne Victoria 3000 Australia COUPLING ARRANGEMENT FOR RECIPROCATING PISTON ENGINE Details of Associated Provisional Application,- PQ2056 filed 5 August 1999 The following statement is a full description of this invention, including the best method of perform~ing it known to us RECEIVED TIME 7. AUG. 18 19 REEIEDTIE .AG. 1819PRINT TIME 8. AUG. 7 :5 8 AUG. 2000 18:40 FREEHILLS MELB 5. 613 392881567 NO. 13 23 P. FREEHILLS MELB 2 The invention relates to reciprocating piston engines, and in particular to coupling arrangements for interconnecting a gudgeon pin and a crankshaft journal of such an engine. The invention is notably applicable to reciprocating two-stroke and four-stroke piston combustion engines and compression engines and it will be convenient to hereinafter describe the invention in relation to tha t exemplary application, although it should be appreciated that the invention is not limited to the application.

Conventional reciprocating piston engines are generally manufactured in two and four stroke designs. A single piston is housed within each cylinder, the piston being connected from a central piston gudgeon pin to a single bearing crankshaft journal by a single solid centre mounted connecting rod. After combustion has .taken place in the combustion chamber of the piston, the energy derived from the expansion of the combustible material forces the piston to travel along the length of the cylinder away from the combustion chamber. This translational movement is *.15 transferred via the connecting rod to the crankshaft journal and is transformed into a rotational movement as the crankshaft is driven around its longitudinal axis. As the *.crankshaft completes each revolution, the connecting rod interconnecting the crankshaft journal and the gudgeon pin forces the piston back along the length of the cylinder towards the combustion chamber, where either combustion once again takes place (two-stroke engines) or an intake stroke occurs (four-stroke engines).

Conventional engines of this type are arranged so that the intake and exhaust strokes (two-stroke engines) or the induction, compression, expansion and exhaust strokes (four-stroke engines) are of constant stroke length. This property represents a kinematic limitation in conventional reciprocating piston engines and results in the loss of a considerable amount of thermodynamic energy per cycle. By way of explanation, in a conventional four-stroke reciprocating piston engine, the expansion stroke is equal to the compression stroke. This results in the exhaust valve opening while the pressure inside the cylinder is still well above the barometric value. The pressure differences represents work that is lost by the engine.

RNM;DL 40451942 CAP 4 AugUwc 2000 RECEIVED TIME TAUG. 18:19 RECIVE TIE 7 AU. 1:19PRINT TIME 8* AUG. 7:58 7, AUG. 2000 18:40 FREEHILLS MELB 5. 613 392881567 NO. 1323 P. 91 FREEHILLS MELB 3 It would be desirable to provide a reciprocating piston engine which is able to minimise the thermodynamic energy losses of known reciprocating piston engines.

It would also be desirable to provide a reciprocating piston engine which overcomes or ameliorates one or more of the disadvantages of known reciprocating piston engines.

With this in mind, the present invention provides a coupling arrangement for use with a reciprocating piston engine including a crankcase, a piston and a corresponding cylinder, and an output shaft, wherein the coupling arrangement acts to interconnect the gudgeon pin to the output shaft, the coupling arrangement comprising: a connecting member having a first end pivotally connectable to the gudgeon pin; a crankcase gear mounted within the crankcase; 15 a cam disc gear mounted for meshing with and rotation around the crankcase gear; mounting means for pivotally attaching a second end of the connecting member to the cam disc gear at a radially displaced position from the centre of the cam disc gear; and 20 transfer means interconnecting the output shaft portion and a journal portion laterally projecting from the cam disc gear, the transfer means acting to transform the rotational movement of the cam disc gear about the crankcase gear into a rotational movement of the output shaft portion.

In one embodiment of the invention, the transfer means comprises a crankshaft interconnecting the crankcase gear to the crankcase cover, a crankshaft gear for rotatably mounted around the crankshaft, a crankshaft arm fixedly interconnecting the crankshaft gear and the cam disc gear, and an output shaft gear fixably mounted about the output shaft and meshing with the crankshaft gear.

In another embodiment of the invention, the output shaft acts as a crankshaft, the output shaft passing through the crankcase gear. In this case, the transfer means RNMDL 40451942 CAP 4 August 2000 RECEIVED TIME 7. AUG. 18:19PRN TIE 8AU. PRINT TIME 8.AUG- 7:58 IAUU. 2UU 18 :4 1 FNLLHILLS MEL 5. 61 A.3 92881561 NO. 1323 P. 92 FREEHILLQV MELB 4 may comprise a crankshaft arm radially projecting from the output shaft and being rotatably attached at a first end to the crankshaft journal portion.

The mounting means may comprise a cam disc arm radially projecting from the cam disc gear, the cam disc airm having a proximate end fixedly attached to the cam disc gear and a distal end to which the second end of the connecting member is pivotally attached.

Another aspect of the present invention provides a coupling arrangement for use with a reciprocating piston engine including a crankcase, a piston and a corresponding cylinder, and at least two output shaft portions, wherein the coupling arrangement acts to interconnect the gudgeon pin to the two output shaft portions, the coupling arrangement comprising: connecting member having a first end pivotally connectable to the gudgeon pin; a first crankcase gear mounted within the crankcase at a first side; a first cam disc gear mounted for meshing with and rotation around the first crankcase gear; *a first mounting means for pivotally attaching a second end of the connecting member to the first camn disc gear at a radially displaced position from the centre of the first cam disc gear; a first transfer means interconnecting the first output shaft portion and a first journal portion laterally projecting from the first cam disc gear, the first transfer means acting to transform the rotational movement of the first cam disc gear about the first crankcase gear into a rotational movement of one of said output shaft portions; a second crankcase gear mounted within the crankcase at a second side; a second cam disc gear mounted for meshing with and rotation around the second crankcase gear; second mounting means for pivotally attaching the second end of the connecting member to the second cam disc gear at a radially displaced position from the centre of the second cam disc; and RNM;DL 40451942 CAP 4 August 2000 RECEIVED TIME 7. AUG. 18:19 R TTIE 8AU. 7 7 PRINT TIME 8. AUG. 7:57 7. AUG. 2000 18:41 FREEHILLS MELB 5. 61 13 92881567 NO. 1323 P. 93 FREEH ILLS MELB second transfer means interconnecting the second output shaft portion and a second journal portion laterally projecting from the second cam disc gear, the second transfer means acting to transform the rotational movement of the second cam disc gear about the second crankcase gear into a rotational movement of the other of said output shaft portions.

A further aspect of the present invention provides a coupling arrangement for use with reciprocating piston engine including a crankcase, a plurality of pistons and corresponding cylinders, and an output shaft, wherein the coupling arrangement acts to interconnect the gudgeon pins of the plurality of pistons to the output shaft, the coupling arrangement comprisinga plurality of connecting members each having a first and pivotally connectable to a separate one of said gudgeon pins; at least one crankcase gear mounted within the crankcase; at least one cam disc gear mounted for meshing with and rotation around the 15 crankcase gear; at least one mounting means pivotally attaching a second end of a first of said connecting members to the cam disc at a radially displaced position from the centre of the cam disc; and at least one transfer means interconnecting the output shaft and a journal 20 portion laterally projecting from the cam disc gear, the transfer means acting to transform the rotational movement of the camn disc gear about the crankcase gear into a rotational movement of the output shaft, the remaining connecting members each being connected to a separate journal portion laterally displaced from the other journal portions, adjacent journal portions being interconnected by journal arm members.

The various advantages and features of the invention will be better appreciated from the following description which refers in more detail to the various features of the coupling arrangement of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying drawings where the coupling arrangement is illustrated in preferred RNM:DL 40451942 CAP 4 AuSUMI2000 RECEIVED TIME 7. AUG. 18:19 RECIVE TIE 7 AU. 1:19PRINT TIME 8. AUG. 7:57 I. ?UU. 2000 18:41 FREEHILLS MELB 5. 61 £3 92881567 NO. 1323 P. 94 FREEHILLS MELB 6 embodiments. It is to be understood, however, that the coupling arrangement of the present invention is not limited to the embodiments illustrated in the drawings.

In the drawings: Figure 1 s a schematic front view of a reciprocating piston engine including a fist embodiment of a coupling arrangement according to the present invention; Figure 2 is a side view of the reciprocating piston engine of Figure 1; Figure 3 is a front view of a reciprocating piston engine including a second embodiment of the coupling arrangement according to the present invention; Figure 4 is a side view of the reciprocating piston engine of Figure 3.

Figure 5 is a side view of reciprocating piston engine including a second embodiment of a coupling arrangement according to the present invention; *.:Figure 6 is a front view of the reciprocating piston engine of Figure Figure 7 is a side view of a reciprocating piston engine including a third embodiment of a coupling arrangement according to the present invention, and, Figure 8 is a graphical representation of the piston position of a reciprocating piston engine including the coupling arrangement of Figures 1 and 2.

Referring now to Figure 1, there is shown generally a single piston within a 9 reciprocating piston engine. The piston 1 is located within a cylinder 2. The engine also includes a crankcase 3 which, in this case, is integral with the cylinder 2. The engine includes a first and a second output shaft portion, respectively referenced 4 and 5. The piston 1 incorporates a piston gudgeon pin 6.

A coupling arrangement is provided for interconnecting the piston gudgeon pin 6 and the output shaft portions 4 and 5. This coupling arrangement comprises a connecting member 7 having a first end 8 pivotally connectable to the gudgeon pin 6. The coupling arrangement also includes a crankcase gear 9 which, in this example, is fixably mounted within the crankcase 3. In this case, the crankcase gear 9 is connected to the crankcase 3 by means of a crankshaft portion 10. The crankshaft portion 10 may be integral with the crankcase 3. The crankcase gear 9 is fixably mounted to the end of the crankshaft portion 10 so that rotation of the gear with respect to the crankshaft portion 10 is not possible.

RNM'DL 40451942 CAP 4 August 200 RECEIVED TIME 7,AUG. 18:19 RECIVD TME 7.LG. 1819PRINT TIME 8. AUG. 7:57 I. AUU. 2000 18:41 FREEHILL%) MELB 5. 61,13392881567 NO. 1323 P. FREEHILLS MELB 7 The coupling arrangement also includes a cam disc gear I11 mounted within the crankcase 3 for meshing with and rotation around the crankcase gear 9.

Mounting means are provided for pivotally attaching a second end 12 of the connecting member 7 to the cam disc 11 at a radially displaced position from the centre of the cam disc 11. In the embodiment illustrated in Figures 1 and 2, the mounting means are provided by a cam disc gudgeon pin 13 laterally projecting from one face of the cam disc gear 11I and projecting through a corresponding aperture in the second end 12 of the connecting member 7.

The coupling arrangement further comprises transfer means interconnecting the output shaft portion 4 and a crankshaft journal portion 14 laterally projecting from the cam disc gear. In this example, the transfer means comprises a crankshaft gear 15 rotatably mounted around the crankshaft 10. In the illustrated example, the crankshaft gear 15 is mounted on a sleeve 16 over the exterior surface of the crankshaft portion 10. A crankshaft arm 17 fixedly interconnects the crankshaft gear 15 and the cam disc gear 11. The crankshaft arm 17 is provided with an aperture through which the crankshaft journal portion 14 passes so as to complete the interconnection. In addition, an output shaft gear 18 is fixedly mounted about the output shaft portion 4 so as to mesh with the crankshaft gear 20 As can be best appreciated from Figure 2, it is possible with such an arrangement to dispose the various elements of the coupling arrangement in such a way that, the crankshaft arm 17 is not at a top centre position when the piston 1 is at top dead Centre position, but rather is at an angle thereto. Downward force applied by the piston, once compression occurs, is transferred to the cam disc gear 11I by means of the connecting members 7. Since the crankcase gear 9 is fixed with respect to the crankcase 3, rotation of the cam disc gear 11 about the crankcase gear 9 is caused. This rotational movement is transformed into a corresponding rotational movement of the crankshaft gear 15 about the crankshaft portion 10 by means of the crankshaft arn 17. The intermeshing of the teeth of the output shaft gear 18 and the crankshaft gear 15 ensures that torque is applied to the output shaft portion 4.

RNM:DL 40451942 CAP 4 August 2000 RECEIVED TIME 7. AUG, 18:19PRN TIE 8AU. PRINT TIME 8. AUG. 7:57 I. PUU, 2UU 18:42 FREEHILLSV MLLB 5. 61 A3 92881567 NO. 1323 P. 96 FREEHILLS MELB 8 In order to evenly distribute the internal forces applied to the various elements of the reciprocating piston engine during operation, the coupling arrangement may include a second crankcase gear 19, and cooperating second cam disc gear 20 as well as a second mounting means for interconnecting the connecting member 7 to the cam disc gear 20, and a second transfer means for interconnecting the second output shaft portion 5 and the cam disc gear 20. Such an arrangement is illustrated in Figure 1. As seen in this figure, the first crankcase gear 9, first cam disc gear 11 and corresponding mounting and transfer means are located on the opposite side of the connecting member 7 to the second crankcase gear 19, second cam disc gear 20 and corresponding mounting and transfer means.

As was the case with the first crankcase gear 9, the second crankcase gear 19 is connected to the crankcase 3 by means a crankshaft portion 21. The shaft 21 may be integral with the crankcase. The crankcase gear 19 is mounted so as to not be rotatably movable about the longitudinal axis of the shaft 21. The second cam disc gear 20 is mounted for meshing with in rotation around the second crankcase gear 19. The second mounting means are provided in the form of a cam disc arm 22 radially projecting from the cam disc gear 20 to enable the pivotal attachment of the second end 12 of the connecting member 7 to the second cam disc 20 as a radially displaced position from the centre of the second cam disc The output shaft portion 5 is connected to a second crankshaft journal portion 23 laterally projecting from the second cam disc gear 20 so as to transform C...the rotational movement of the cam disc gear 20 about the crankcase gear 19 into a rotational movement of the output shaft portion 5, by a crankshaft gear 24 rotatably mounted around the crankshaft 21 on a sleeve 25, an output shaft gear 26 fixedly attached to the output shaft portion 5 and intermeshing with the cam shaft gear 24 and a cam shaft arm 27 radially projecting from the sleeve 25 and engaging the crankshaft journal portion 23 by means of a corresponding aperture.

Figure 3 shows an alternative embodiment of the coupling arrangement illustrated in Figure In this arrangement, a crankcase gear 30 is fixedly mounted within the crankcase 3 and a cam disc gear 31 is mounted within the crankcase 3 for meshing with and rotation around the crankcase gear 30. However, in this case, the RNM:DL 40451942 CAP 4 August 2000 RECEIVED TIME 7. AUG. 18:19PRN TIE 8AU. 7 7 PRINT TIME 8. AUG. 7:57 7. AUG. 2000 18:42 FREEHILLS MELB 5. 61 £3 92881567 NO. 13 23 P 97 FREEHILLS MELB 9 crankshaft 32 acts as the reciprocating piston engines output shaft, passing through the centre of the crankcase gear 30. A crankshaft journal portion 34 projects laterally from the cam disc gear 3 1. In this example, transfer means interconnecting the crankshaft/output shaft 32 and the crankshaft journal portion 34 are provided by way of a crankshaft arm radially projecting from the crankshaft/output shaft 32 and being rotatably attached at a first end to the crankshaft journal portion 34, by means of an aperture provided in that end. A cam disc arm 35 is also provided which radially projects from the cam disc gear in order to provide the mounting means pivotally attaching the second end of the connecting member 7 to the cam disc 3 1.

The cam disc arm 35 has a proximate end fixedly attached to the cam disc gear (in this case attached directly to the crankshaft journal portion 34) and a distal end to 4 4* which the second end 36 of the connecting member 7 is pivotally attached.

Once again, in order to more evenly distribute the internal forces within the reciprocating piston engine, a second cam disc gear, crankshaft gear and corresponding mounting and transfer means may be provided on the opposite side of the connecting member 7 to the first crankcase gear 30, cam disc gear 31 and corresponding mounting and transfer means.

The principle of operation of either of the embodiments of the coupling arrangement according to the present invention illustrated in Figures I to 3 may be 20 adapted for use in a reciprocating piston engine including a plurality of pistons.

Figure 4 represents one example of a coupling arrangement suitable for use in a multi-piston engine. In this figure, the combination of elements viewed along the line A-A correspond to the features just described in Figure 3. In addition, however, additional connecting members 40, 41 and 42 are provided for connection to the gudgeon pins of corresponding additional pistons, at the locations respectively referenced 43, 44 and 45. The connecting members 7, 40, 41 and 42 are each connected at a second end to a separate crankshaft journal portion 50, 5 1, 52 and 53. Each of the crankshaft journal portions 50 to 53 are laterally displaced from the other crankshaft journal portions. Adjacent crankshaft journal portions are interconnected by crankshaft journal arm members 54, 55 and 56. The accommodation of each of the crankshaft journal portions 50 to 53 and the RNM:DL 40451942 CAP 4 Auguat 2000 RECEIVED TIME 7. AUG. 18:19PRN TIE 8AU. PRINT TIME 8,AUG, 7:57 7. AUG. 2000 18:43 FREEHILLS MELB 5. 61 £3 92881567 NO. 1323 P. 98 FREEHILLS MELB crankshaft journal arm members 54 to 56 results in a segmented crankshaft to which each of the connecting members 7, 40, 41 and 42 are connected. According to such an arrangement, each of the four cylinders and associated connecting arms may be used to drive the cam disc gear 31 around the exterior of the crankcase gear As in previous embodiments, a second crankcase gear 60, cam disc gear 61 and associated mounting means and transfer means may also be provided in the coupling arrangement illustrated in Figure 4.

Figure 5 shows a further embodiment of the coupling arrangement illustrated in Figure 1. In this arrangement, a crankcase gear 70 is no longer fixedly mounted within the crankcase 3, but is mounted within the crankcase 3 so as to be freely rotatably about a crankshaft/output shaft 71. The crankshaft/output shaft 71 has a **:longitudinal axis radially displaced from the centre of the crankcase gear 70. In the sees example shown in Figure 5, the crankshaft 71 and the centre of the crankcase gear 70 are interconnected by means of a crankshaft arm 72. In other embodiments, the *West: .0 15 crankshaft 71 may be directly attached to the crankcase gear 70 at a position which is radially displaced from the centre of the crankcase gear The cam disc gear 31 is mounted within the crankcase 3 so as to mesh with sees and rotate around the crankcase gear 70. A crankcase gear shaft 73 projects laterally from the centre of the centre of the crankcase gear 70, whilst a cam disc gear shaft 74 similarly projects from the Centre of the cam disc gear 31. As can be best seen in Figure 6, the cam disc arm 35, in this example, interconnects the cam disc gear shaft 74, at a point distal the cam disc gear 31, and the cam disc gudgeon 00**0 pin 13 at the second end 36 of connecting member 7. A cam disc connecting member 75 interconnects the cam disc gear shaft 74 and the crankcase gear shaft According to such an arrangement, the cam disc arm 35 and the crankshaft 71 are able to move independently of each other, resulting in a substantially reduced mechanical loss during operation of the reciprocating piston engine.

The internal forces may once again be more evenly distributed during operation of the reciprocating piston engine by the provision of a second cam disc gear 76, crankcase gear 77 and corresponding mounting and transfer means on the RNM:DL 4045 1942 CAP 4 August 2000 RECEIVED TIME 7. AUG. 18:19PRN TIE 8AU. :5 PR I NT T I ME 8. AUG. 7 5 7 AUU. 2000 18:43 FREEHILLS MELB 5. 61 £3 92881567 NO. 1323 P. 99 FREEHILLS MELB opposite side of the connecting member 7 to that of the first crankcase gear 70, cam disc gear 31 and corresponding mounting and transfer means.

Figure 7 shows a further embodiment of the coupling arrangement of the present invention in which the reciprocating piston engine includes more than one piston. In this example, the reciprocating piston engine includes four radially mounted pistons 80, 81, 82 and 83, each adapted for reciprocating movement towards and away from a common intersection point The coupling arrangement includes a crankshaft gear 86 and cam disc gear 87, both functionally identical to the crankshaft gears and cam disc gears previously described. However, each piston 80 to 83 is provided with a corresponding connecting member, respectively 88 to 91, connected at a first and to the gudgeon pin of that piston. The connecting members 88 to 91 are interconnected at a common location 92 radially displaced from the centre of the cam disc gear 87.

In this arrangement, each of the pistons 80 to 83 act to provide a down stroke 15 which drives the cam disc gear 87 around the crankshaft gear 86, and hence cause rotation of the output shaft of the reciprocating piston engine, during a different part of the cycle of operation of the engine.

Figure 8 provides a graphical representation of the varying stroke lengths which can be achieved according to the present invention., This figure is illustrative of the position of the piston 1 of Figure 2 within the cylinder 2 against an angle formed between the crankshaft arm and the longitudinal axis of the cylinder 2 shown in Figure 2. It can be seen from Figure 8 that a coupling arrangement having the characteristics described in the previous paragraph provides an expansion/exhaust stroke which is significantly longer than the induction/compression stroke. Accordingly, the pressure difference between the pressure inside the cylinder 2 and the ambient pressure which occurs in conventional reciprocating piston engines at the end of an expansion stroke is no longer wasted. The coupling arrangement according to the present invention is able to utilise this pressure difference due to the fact that the piston 1 can move further in expansion than in compression, and is therefore more thermodynamically efficient than conventional reciprocating piston engines.

RNM:DL 40451942 CAP 4 Auguat 2000 RECEIVED TIME 7. AUG. 18:19 RECIVD TME 7. UG 1819PRINT TIME 8. AUG. 7:57 AUU 2000 18:43 FREEHILLS MELB 5. 61 3 92881567 FREEHILLS MELB NO. 1323 P. 100 It will be appreciated from the foregoing that this principle can be applied to can be applied to situations in which alternating piston stroke lengths may be advantageous. By selecting at least the relative initial angular positions of the crankshaft arm and connection member, and the relative dimensions of the crankshaft arm, connection member and connecting rod, a coupling arrangement is provided which causes the stroke length of the piston within the cylinder to alternate between a first and a second value. Moreover, the stroke lengths may also be affected by the selection of the gear ratio of the two or more gears from which the rotation synchronisation means is formed.

Those skilled in the art will appreciate that there may be variations and modifications of the connection arrangement described herein which are within the scope of the present invention.

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RNM:DL 40451942 CAP 4 August 2000 RECEIVED TIME TAUG. 18:19 PRINT TIME 8. AUG. 7:57

Claims (8)

1. 2. A coupling arrangement according to claim 1, wherein the transfer means comprises a crankshaft interconnecting the crankcase gear to the crankcase cover, a 0-0.0 20 crankshaft gear for rotatably mounted around the crankshaft, a crankshaft arm fixedly interconnecting the crankshaft gear and the cam disc gear, and an output shaft gear fixably mounted about the output shaft and meshing with the crankshaft gear.
2. 3. A coupling arrangement according to claim 1, the output shaft acts as a crankshaft, the output shaft passing through the crankcase gear.
3. 4. A coupling arr angement according to claim 3, wherein the transfer means comprises a crankshaft arm radially projecting from the output shaft and being rotatably attached at a first end to the crankshaft j ournal portion. A coupling arrangement according to any one of the preceding claims, wherein the mounting means comprises a cam disc arm radially projecting from the cam disc gear, the cam disc arm having a proximate end fixedly attached to the cam RNM:DL 40451942 CAP 4 August 2000 RECEIVED TIME 7. AUG. 18:19PRN TIE 8AU. 7 7 PR I NT T I ME 8. AUG. 7 5 7
4. 7. AUG. 2000 18:44 FREEHILLS MELB 5. 61 £3 92881567 NO. 1323 P. 102 FREEHILLSV MELB 14 disc gear and a distal end to which the second end of the connecting member is pivotally attached. 6. A coupling arrangement for use with a reciprocating piston engine including a crankcase, a piston and a corresponding cylinder, and at least two output shaft portions, wherein the coupling arrangement acts to interconnect the gudgeon pin to the two output shaft portions, the coupling arrangement comprising: a connecting member having a first end pivotally connectable to the gudgeon pin; a first crankcase gear mounted within the crankcase at a first side; a first cam disc gear mounted for meshing with and rotation around the first crankcase gear; a first mounting means for pivotally attaching a second end of the connecting ::*member to the first cam disc gear at a radially displaced position from the centre of the first cam disc gear; 15 7. A coupling arrangement according to claim 6, wherein the first and second transfer means comprise respectively first and second crankshafts interconnecting the first and second crankcase gears to the crankcase cover, first and second crankshaft gears rotatably mounted around the first and second crankshafts, first and second crankshaft arms fixedly interconnecting the first and second crankshaft gears and the first and second cam disc gear, and first and second output shaft gears fixably mounted about the first and second output shaft portions and meshing with first and second crankshaft gears.
5. 8. A coupling arrangement according to claim 1, wherein the first and second output shaft portions act as crankshafts, the first and second output shaft portions passing through the first and second crankcase gears.
6. 9. A coupling arrangement according to claim 3, wherein the transfer means comprises first and second crankshaft arms radially projecting from the first and second output shaft portions and being rotatably attached at a first end to the crankshaft journal portion.
7. 10. A coupling arrangement according to any one of claims 6 to 9 the preceding claims, wherein the mounting means comprises first and second cam disc arms RNM:DL 40451942 CAP 4 August 2000 RECEIVED TIME 7,AUG. 18:19PRN TIE 8AU. 76 P R I N T T I ME 8. AUG. 7:56 I. AUG. 2000 18:44 FREEHILLS MELB 5. 61 A3 92881561 NO. 1323 P. 103 FREEHILLS MELB radially projecting from the cam disc gear, the first and second cam disc arms each having a proximate end fixedly attached to the cam disc gear and a distal. end to which the second end of the connecting member is pivotally attached.
8. 11. A coupling arrangement for use with reciprocating piston engine including a crankcase, a plurality of pistons and corresponding cylinders, and an output shaft, wherein the coupling arrangement acts to interconnect the gudgeon pins of the plurality of pistons to the output shaft, the coupling arrangement comprising: a plurality of connecting members each having a first and pivotally connectable to a separate one of said gudgeon pins; at least one crankcase ger mounted within the crankcase; at least one cam disc gear mounted for meshing with and rotation around the crankcase gear; least one mounting means pivotally attaching a second end of a first of .::said connecting members to the cam disc at a radially displaced position from the 15 centre of the cam disc; and at least one transfer means interconnecting the output shaft and a journal portion laterally projecting from the can disc gear, the transfer means acting to transform the rotational movement of the cam disc gear about the crankcase gear :*into a rotational movement of the output shaft, the remaining connecting members 20 each being connected to a separate journal portion laterally displaced from the other journal portions, adjacent journal portions being interconnected by journal arm members. RNM:DL 40451942 CAP 4 Augunt 2000 RECEIVED TIME 7-AUG. 18:19 RECIVD TME 7. UG 1819PRINT TIME 8. AUG. 7:56