US1276381A - Rotary engine. - Google Patents

Description

T. J. LOFTUS. ROTARY ENGINE. APPLICATION FILED OCT. 1 6. 1917.

Patented Aug. 20, 1918.

2 SHEETS-SHEETI WITNESS:

A TTORNE YS.

T. 1. LOFTUS.

ROTARY ENGlNE.

APPLICATION FILED OCT. l6. 19]?- 1,276,381 Patented Aug. 20, 1918. I

I 2 SHEETSSHEET 2.

any VENTOR,

T/I/DWS IL $u ,iNES.

WITNESS:

E STATES PATEN THOMAS J. LOFTUS, OF CASTELLA, CALIFORNIA, ASSIGNOR OF ONE-HALF TO HARD/[ON BELL, OF OAKLAND, CALIFORNIA.

ROTARY ENGINE.

Specification of Letters latent. Patented Aug. 20, 1918.

Application filed October 16, 1917. Serial No. 196,819.

To all whom it may concern:

Be it known that I, THOMAS J. Lor'rus, a citizen of the United States, residing at Castella, in the county of Shasta and State of California, have invented new and useful Improvements in Rotary Engines, of which the following is a specification.

This invention relates to a rotary engine of the internal combustion, multi cylinder t pe, and particularly to improvements over t e structure shown in my co-pending application entitled rotary engine, filed August 15th, 1917, Serial Number 186,306.

One of the objects of the present inven-.

tion is to provide a rotary cylinder, internal combustion engine operating on the fourcycle principle, in which the crank case and cylinder are mounted eccentrically with relation to the crank shaft and in which both the cylinders and crank shaft revolve. An-- other object of the invention is to provide a crank shaft to which two revolutions are imparted while the cylinders make one revolution; and also to provide a novel cam arrangement whereby two reciprocations are imparted to the pistons during one revolution of the cylinders to permit a perfect charging and scavenging of the cylinders. Further objects will hereinafter appear.

The invention consists of the parts and the construction and combination of parts as hereinafter more fully describedv and claimed, having reference to the accompanying drawings, in Which Figure 1 is a central. vertical, longitudinal section through the engine.

Fig. 2 is a central, vertical, cross section.

Fig. 3 is a'front view of the cam head, showing the position of the inlet valve cam.

Fig. 4 is a front view of the cam head which carries the exhaust valve cam.

Fig. 5 is another view of one of the cam heads. showing a modification in the construction of same.

Referring to the drawings in detail, A and B indicate a pair of bearing members, in

which are journaled, respectively, a crank shaft 2 and a cylinder shaft 3. Suitably secured or formed integral with the cylinder shaft is a crank casing 4, and radially positioned with relation to the cylinder shaft exlliaust valve 7 and aninlet valve 8, the va ves employed being of the puppet type.

Each valve is provided with a stem 9 surrounded by a spring 10 which engages a collar 11, thereby providin a means for normally retaining each Va ve on its seat.

bearing B. The cylinder" shaft is journaled both in the bearing B and on the stationary shaft 16. The cylinder shaft may, therefore, be termed a sleeve shaft having both an interior and an exterior support. One side of the crank case supporting the cylinders is provided with a number of cored passages 17, one for each cylinder and inlet valve 8.

The inner ends of these cored passages communicate with perforations 'formedin the sleeve shaft and also in the hollow stationary shaft 16, while the outer ends are connected through pipes 18 with the intake ports formed in the cylinders. .The hollow stationary shaft may, therefore, be directly connected with a carbureter of any suitable construction and the gas admitted will thus' travel through the stationary, hollow shaft and the perforations formed therein, thence through the cored passages and pipes 18 directly to each inlet valve, the admission of gas being controlled by opening and closing the inlet valves by means of a cam 19 formed on the outer head l-l; that is, the inner ends ofthe stems carrying the valves 8 are so positioned that they wlll engage the cam 19 once during each revolution of the cylinders, thus providing a means for lifting each inlet valve once during each revolution of the cylinders. The exhaust valves are also opened once during each revolution of the cylinders by means of a cam 20 formed on the outer periphery of the stationary cam head 13.

I'journal section 23. These journal sections periphery of the stationary cam are separated, as shown at 2 1, to permit the connecting arms to straddle the crank arms 25 carried by the crank shaft and also to permit a perfect engagement, as will hereinafter be described, with a doublecrank pin 26 carried by each crank. One side of each journal member 23 is provided with a pin extension 27 which supports a roller 28, said rollers being so positioned that they will always .run in engagement with a pair of circular cam grooves 29 and 30 formed in each ca'm head 13 and 1 1.

The crank shaft, as previously stated, is

eccentrically positioned with relation to the.

crank case and the cylinders. The crank arms and pins 26 carried thereby are, furthermore, so short that a positive connection between the rigid piston connecting rods and the pins cannot be obtained. It may, furthermore, be stated that such engagement 'is neither desired nor intended, as one of the objects of the present inventionis to permit two reciprocations of each piston and two complete revolutions of the crank shaft to each revolution of the cylinders, the two reciprocations of the pistons during one'revolution of the cylinders permitting a four-cycle operation and simultaneously reduces the cylinder speed to onehalf of that which-is required in ordinary standard four-cycle revolving cylinder engines. The centrifugal strains to which such cylinders are subjected are entirely overcome by the present structure, as the comparatively slow speed of the cylinders with relation to the crank shaft permits a high propeller speed and a low cylinder speed. Lighter material and a more compact construction and assembly are also permitted in the present instance; and the emciency is rather higher, due to the longer opening period of both the intake and exhaust valves.

The operation of the engine will be as follows: Referring to Figs. 2, 3 and 4, the sweep of the crank pins 26 conforms to or travels in exact alinement with the lower half 30 of the cam grooves formed in the heads 13 and 14. The movement of the pistons is not only positively timed and'regulated by the grooves 29 and 30 but also by the revolution of the crank shaft. To illustrate the movement of the pistons during one revolution, we might commence with the suction stroke of a single piston. In that instance, commencing with the piston shown in cylinder 5*, which is in alinement with the intake cam 19, it might be stated that the inlet valve remains open during the travel of the cylinder from the point indicated at 31 to the point 32. The piston travels inwardly during this movement of the cylinder, due to the engagement of the rollers 28 with the upper half of the cam groove 29, a complete inward movement of navaser the piston being obtained when the cylinder reaches the point 32. The piston will similarly travel outward until the point 33 is reached, thus fully compressing the charge admitted. This outward movement is due not only to the shape of the lower half ofthe cam grooves 30, but also to the fact that the connecting rod bearings 23 are engaged by the crank pins'26, thereby forcing the piston outwardly during the revolution of the cylinders from the point 32- to the point 33.

Ignition takes place in a position preferably ahead of the point 33- and burning of the gases will, therefore, force the piston inwardly against the crank pins, thereby imparting the power stroke; a complete expansion or burning of the gases having taken place when the cylinder reaches the point 34. The exhaust cam, carried by the head 13, is engaged at this point and the valve remains open while the cylinder travels from the position shown at 31 to the point 31 and outward movement of the piston being insured by the shape of the upper half of the cam grooves 29.

One reciprocation of each piston takes place while the pistons travel in engagement with their crank shaft pins and the second reciprocation of each piston takes place during the other half of the revolution of the cylinders or when the pistons travel free of the crank pins but in engagement with the upper halves 29 of the cam groovesl Engagement of a piston with a crank shaft pin takes place during one whole revolution of the crank shaft and during one half of a revolution of the cylinders, that is, a crank pin engages a piston connecting rod at the point 32, shown in Figs. 2 and 3, and does not leave the connecting rod until thepoint 3'4 is reached. Two revolutions are transmitted to the crank shaft during one revolution of the cylinders and two reciprocations are also transmitted to each piston during one revolution of the cylinders, thereby permitting a four-cycle operation and a complete charging and scavenging of each cylinder due to the long'opening period permitted by the position of the cams 19 and 20.

While any suitable form of ignition system may be employed, an adjustable wlpe contact member 36 carried by the bearing I a pipe 40, the running fit preventing any unnecessary leakage around the stationary cam heads and the revolving cylinders. I also wish it understood that the materials and finish employed in general may be such as the experience and judgment of the manufacturer may dictate.

The construction of the crank shaft and pistons here provided is identical to that shown in my co-pending application, but the feature which forms the important part of the present application is the provision of double cam grooves 29 and 30 and mechanically operated valves for the admission and scavenging of the charges, the specific construction and manner of introducing the charges being immaterial as it is obvious that any suitable arrangement may be provided.

By referring to Fig. 5, it will be seen that the upper cam section 29 is larger than those illustrated in Figs. 3 and 4. This is of great importance particularly Where an engine of the type described is employed for aviation purposes. That is, the large cam 29 provided increases the stroke of the piston during the scavenging and suction charge. Increased stroke causes the piston to enter What is normally termed the compression space, thereby serving as a means for completely scavenging the gases on the exhaust stroke and also serving as a means for increasing the volumetric charge of the cylinder during the suction stroke. The importance of this can readily be appreciated when it is taken into consideration that aviation engines often travel at such heights that the atmospheric pressure is so reduced that comparatively low compression is obtained during the compression strokes of the pistons. Any increase in volumetric capacity under such conditions is therefore a vital factor in the successful operation of an engine of this type.

Another. feature obtained is an increase in length of both the exhaust and inlet cams which further facilitates a more complete' scav nging and charging of the cylinders.

Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. A four-cycle rotary internal combustion engine comprising a plurality of revolving cylinders, a revolving crank shaft eccentrically positioned with relation to the cylinders, a piston in each cylinder, means for transmitting piston movement to revolve the crank shaft and means for transmitting two reciprocations to each piston during one revolution of the cylinders. said means also adapted to increase the length of the piston stroke during one-half revolution of the cylinders and decrease the length during the ther half of the revolution of the cylinders.

A four-cycle rotary internal combustion engine comprising a plurality of revolving cylmders, a piston in each cylinder,

a rigid connecting rod in each piston, a.

ton during one revolution of the cylinders.

3. A four-cycle rotary internal combustion engine comprising a plurality of revolving cylinders, a piston in each cylinder, a rigid connecting rod in each piston, a bearing member on the lower end of each connecting rod,.a revolving crank shaft eccentrically positioned with relation to the cylinders, crank pins on said shaft, means causing the rigid connecting rod bearings to engage the crank pins during one-half revolution of the cylinders and to transmit two revolutions to the crank shaft during one revolution of the cylinders and a pair of,

stationary cam members controlling the re oiprocal movement of each piston, said cam members adapted to lengthen the piston stroke during the exhaust and charging cycle and to decrease the stroke during the compressing and firing cycle.

4:. A four-cycle rotary internal conibustion engine comprising a plurality of revolving cylinders, a piston in each cylinder, a rigid connecting rod in each piston, a bearing member on the lower end of each connecting rod, a revolving crank shaft eccentrically positioned with relation to the cylinders, crank pins on said shaft, means causing the rigid connecting rod bearings to engage the crank pins during one-half revolution of the cylinders and to transmit two revolutions to the crank shaft during one revolution of the cylinders, a pair of stationary cam members controlling the reciprocal movement of each piston,said cam members adapted to lengthen the pistonstroke during the exhaust and charging cycle and to decrease the stroke during the compressing and firing cycle, an inlet valve and an exhaust valve in each cylinder, and an inlet and an exhaust cam formed 'onthe first named cam members adapted to alternately open and close the inlet and exhaust valves in each cylinder.

5. A rotary cylinder engine comprising a crank case, a plurality ofradially disposed cylinders secured to the crank case, a cylinder shaft journaled to rotate carrying the crank case and cylinders, a crank shaft journaled to rotate independently of the c linder shaft and positioned eccentrically tfiereto, a piston in each cylinder, a rigid 1 engaged by vthe connecting rod bearings v, during a. portion of the revolution of the crank case and cylinders,

connecting rod on each piston, a stationary cam head at each end of the crank case, each head having two connected circular superposed grooves formed on their inner sides, a bearing member on the inner end of each connecting rod, a projecting pin on each end of each bearing memberadapted to be received by the circular grooves formed in the cam heads, a plurality ofradially disposed arms onthe crank shaft between the cam heads, and a pin on each arm adapted to be engaged by the connectin rod bearing members during onehalf 0 a revolution of the cylinders.

6. A rotary cylinder engine comprising a crank case, a plurality of radially disposed cylinders securedto the crank case, a cylinder shaft journaled to rotate carrying the a crank shaft journaled to rotate independently of the cylinder shaft and positioned eccentrically thereto, a piston in each cylinder, a rigid connecting rod on each piston, a stationary cam head at each end of the crank case, each head having two connected circular superposed grooves formed on their inner sides, one of said circular grooves being larger in diameter than the other, a projection on each side of each connecting rod adapted tobe receivedby the grooves, a bearing member on the lower end of eachconnecting rod, crank pins on the crank shaft adapted to be cylinders, an exhaust, and an inlet ,valve in each cylinder, and a cam member in each cam head adapted to alternately open said valves once during each cylinders.

7. A rotary cylinder engine comprising a crank case, a plurality of radially disposed cylinders secured to the crank case, a cylinder shaft journaled to rotate carrying the crank case and cylinders, a crank shaft journaled to rotate independently of the cylinder shaft and positioned eccentrically thereto, a piston in each cylinder, a rigid connecting rod on each piston, a stationary cam head at each end of the crank case, each head having -two connected circular superposed grooves formed on their inner sides, a bearing member on the inner end of each connecting rod, a projecting pin on each end of each bearing member adapted to be received by the circular grooves formed in the cam heads, a plurality of radially disposed arms on the crank shaft between the cam heads, a pin on the outer end of each arm adapted to be engaged by the connecting rod bearing members during one-half of a revolution of the cylinder, an exhaust and an inlet valve the outer end of.

.of revolutlon of the cylinders,

revolution of theof the pistons in each cylinder, and a cam member in each cam head adapted to alternately open said valves once during each revolution of the cylinders.

8. A four-cycle rotary internal combustion engine comprising a plurality of revolving cylinders, a revolving crank shaft, means for transmitting power to turn the crank shaft two revolutions during one revolution of the cylinders, a piston in each cylinder, means for transmitting two reciprocations to each piston during one revolution of the cylinders, and means for increasing the length 0 the piston stroke during one-half of a revolution of the cylinders and decreasing the length during the other half of revolution of the cylinders.

'9. A four-cycle rotary internal combustion engine comprising a plurality of revolving cylinders, a revolving crank shaft, means for transmitting power to turn the crank shaft two revolutions during one revolution of thecylinders, a piston in each cylinder, means for transmitting two reciprocations to each piston during one revolution of the cylinders, means for increasing the length of thepiston stroke during onehalf of a revolution of thecylinders and during the other half said means comprising a circular cam groove regulating the stroke of the piston during the compression and firing cycles and a connected larger circular cam groove which controls the stroke of the piston during the exhaust and charging cycle.

10. A four-cycle rotary internal combustion engine comprising a plurality of revolving cylinders, a revolving crank shaft, means for transmitting power to turn the decreasing the length crank shaft, a piston in each cylinder, means for transmitting two reciprocations to each piston durin one revolution of the cylinders, means or increasing the length of the piston stroke during one-half of a revolution of the cylinders and decreasing the length during the other half of the revolution of the cylinders, said means comprising a circular cam groove regulating the stroke of the pistons during the compression and firing cycles and a connected larger circular cam groove which controls the stroke during the exhaust and charging cycles.

lln testimony whereof l have hereunto set my hand in the presence of two sub scribing witnesses.

RICHARD B. GHATDLER, J. A. BELL. I

Images