US 1802902 A
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Description (OCR text may contain errors)
April 28,' 1931. M. BRAU INTERNAL COMBUSTION ENGINE Patented Apr. 28, 1931 PATENT OFFICE MARCEL BEAU, OF RIVESALTES, .PYRENEES-ORIENTALES, FRANCE INTERNAL-COMBUSTION ENGINE Application filed May 2, 1929, Serial No. 359,932, and in France May 12, 1928.
This invention relates to internal combustion engines of the class in which cylinders are arranged parallel to the axis of the engine and the pistons coact with the shaft through connecting rods and a cam drum on the shaft so arranged that there are two complete reciprocations per revolution. The principal object of the invention is to construct an engine in which fixed cylinders are used which can easily be mounted or removed for repairs or to enable the power of the engine to be altered within Wide limits without affecting the balance 1n any way.
One preferred embodiment of the invention is illustrated in the accompanying drawings, but it will be understood that considerable variation may be made without departing from my invention which is particularly defined in the appended claims.
In the drawings,
Figure l is a longitudinal section taken on the line II of Figure 2, one cylinder group being omitted. I
Figure 2 is a plan, partly in section of-the engine, and
Figure 3is a developed View of the cam drum carrying the driving cam and the distributing came.
In Figure 2 it will be seen that the central casing of the engine is of polygonal form, eachside being adapted to receive a group comprising a pair of cylinders. 1 As shown only two groups of cylinders are mounted, the upper group being shown with the cylinder head in position and the lower group partly in section so as to show the interior of the casing.
In the engine shown by way of example in the drawings the polygonal casing has six sides so that the engine can have any even number of cylinders up to twelve.
The central casing 1 is a regular hexagonal right prism, each face 2 being adapted to receive a group of opposed cylinders 4 and 5 which are secured to the casing 1 by studs and nuts 6. The-cylinder group is cut away substantially diametrically where it is secured to the casing 1 as can be seen in Figure 2, the ends of the casing being recessed at 8 to clear the piston skirts. When any side of the casing is not used to support a cylinder, the casing is closed on that side by a plate 7 having exten sions which cover the ends of the corresponding recess 3. Each end face is provided with six bores 8 arranged circumferentially which form or receive guides for the tappets 9 for actuating the valve rockers 10. The casing ends are also provided with suitable bearings 25 to take radial and end loads, for the main shaft 16, a screw device 26 for adjusting end playand a gland 27 and packing 28 for retaining oil.
The drive drum 11 is a cylinder in the face of which is formed as by milling a sinusoidal guideway of such pitch as to cause four piston strokes per revolution, that is one stroke for each 90 of rotation of the shaft.
On each end of the drum 11 is circular cam having a profile comprising a projectlng part 13, a flat part 14 and a hollow part 15. These cams control the distributing valves 29, 36 through the tappe'ts 9, push rods 30 and rockers'lO, and are set in relation to the guideway 12 much as shown in the development in Figure 3, to give the correct valve timing. Contact between the tappet and the cam is-maintained by a return spring as at 38 which must be stronger than the spring of the valve 36.
The main shaft 16 transverses the drum 11 axially and the two are rigidly connected together for example by a conical seating 31 and nut 32 which may be looked, a key 33 being provided if desired for extra security.
The opposed cylinders such as 4 and 5 in each group may have their barrels in a single piece, being made from a bored tubular body closed at each end by a head secured by studs and nuts 6a. Each group of two cylinders is provided with a connecting rod 18 attached at each end to a piston 19. At the centre of the connecting rod is a boss 20 which receives a spindle 21 which may be cast or screwed in, and which carries at one end aroller bearing 22 and at the other a rectangular section die 23 which runs in a longitudinal guideway 24 mounted in the side of the cylinder body thus preventing any rotational movement of the connecting rod about its axis. Each cylinder head 17 is provided with two passages 34, 35 one for admission, the other for exhaust, closed by the valves 29, 36 actuated by the rocker 10 as above mentioned. An additional opening 37 (Fig. 2) is provided to receive a sparking plug.
The complete engine can be assembled as follows. The main shaft 16 is secured in the drum 11, placed in the casing 1, the bearings fitted in position, the two parts of the case firmly fastened together, the end play adjusted and the oil packing devices fitted.
Each cylinder group is assembled by bolting in the guide 24, inserting the connecting rod and pistons in the cylinder body so that the die 23 enters the guideway, and finally securing the cylinder heads.
The required number of cylinder groups are then secured to the casing, the roller devices 22 being entered into the guideway in sodoing. The clearance in the valve gear is set andfinally those recesses 3 in which cylinders are not mounted .are closed by the covers 7.
Once assembled the valve timing is automatically set and remains so permanently. Ignition current may be supplied by any suitable separate means and by mounting the distributor in a definite position on the shaft 16 say by keying or on the drum 11 the ignition timing will also be automatically set.
Naturally suitable exhaust and inlet manifolds and fuel supply means of any suitable construction are provided.
If now the shaft 16 be rotated, the drum 11 also rotates and the pistons will be reciprocated in the cylinders through the guideway 12, rollers 22 and connecting rods 18. The piston stroke obviously depends on the axial length of the guideway 11. Considering any one piston starting from the inner end of the stroke, the corresponding tappet 9 will be held down in the hollow 15 by the return spring 38, inlet valve 36 will be open and the suction stroke takes place. After a rotation of the shaft through 90 the piston will be at the outer end of the stroke, the tappet 9 will have reached the level cam part 14 and the inlet valve will be closed. During the next 90 the piston returns compressing the charge. Towards the end of this stroke the charge is ignited, and the piston is then driven downwards, driving the shaft 16 in so doing through the roller 22 and guideway 12. To-' wards the end of this stroke the tappet 9 is raised by the projecting part 13 of the cam and the exhaust valve 29 is opened. The piston then returns, driving out the burnt gases into the atmosphere.
From the end of this stroke the cycle recommences. It will be observed that the distribution proceeds regularly round the circle and that the firing order for the upper cylinders is 123-456. The lower cylinders fire in the same order but with a phase difference of 90 with respect to the upper cylinders.
As above stated the example illustrated can operate with 2, 4:, 6, 8, 10 or 12 cylinders all removable and interchangeable, without the engine needing to be dismantled. To preserve balance it is advisable as far as p0ssible to remove and replace cylinder groups mounted on diametrically opposite or other symmetrically disposed faces of the casing.
Further, the distributing cams being fixed with respect to the driving drum, the timing is fixed once and for all and cannot be upset.
This has the considerable practical advantage that assembly of the engine can be effected by anyone and the services of a specialist are notrequired.
What I claim is 1. In an internal combustion engine of the class described, the combination of a casing of right polygonal prismatic form having a seating in each side, a main shaft borne axially in said casing, a cylindrical drum on said shaft having a cam formed in. the cylindrical surface thereof, a cylinder secured in one or more of said seatings with-its axis parallel with said shaft, a piston within each said cylinder and means coupling said piston to said cam.
2. In an internal combustion engine of the class described, a casing, a main shaft borne .in said casing, a cylindrical drum on said shaft having a cam formed in the cylindrical surface thereof, a one piece cylinder group comprising a pair of cylinders in line secured to said casing with its axis parallel with said shaft, a piston in each of said cylinders, a connecting rod joining said pistons and means coupling said connectin rod with said cam.
3. In an internal com ustion engine of the class described the combination of a casing, a one piece body comprising a pair of cylinders in line having a fiat seating midway of its length between the cylinders whereby it is secured to said casing, an externally detachable guide secured to said body in its mid part, a plston in each said cylinder, a connecting rod joining said pistons, a cross spindle screwed into said connecting rod, a die block on said cross spindle working-in said guide, a cam upon the engine shaft and a rollor on said cross member coacting with said cam.
4; In an internal combustion engine of the class described the combination of a casing having closable seatings thereon parallel with the engine shaft, a plurality of cylinder bodies each comprising inone piece a pair'of cylinders in 1ine secured in symmetrical arrangementon said casing seatings, a piston in each said cylinder, a connecting rod joining the pair of pistons in each cylinder body, and a cam on the engine shaft coacting with said connecting rods.
In testimony whereof I have signed my name to this specification.
v MARCEL BRAU.