US684883A - Power-transmitting device for engines. - Google Patents

Description

No. 684,883. Patented Oct. 22, |90l.

E. THOMSON.

POWER TBAVNSMITTING DEVICE FOR ENGINES.

(Application filed Nov. 16, 1900.)

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NITED STATES PATENT OFFICE.

LIHU THOMSON, OF SWAMPSOOTT, MASSACHUSETTS.

POWER-TRANSMITTING DEVICE FOR ENGINES.

rSIECIIFEIGA'JJIOIBT forming part of Letters Patent No. 684,883, dated October 22, 1901.

Application filed November 16, 1900. Serial No. 36,688. (No model.)

To @ZZ whom t may concern,.-

Be it known that I, ELIHU THOMSON, a citizen of the United States, residing at Swampscott, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Power-Transmittiug Devices for Engines, (Oase No. 1,850,) of which the following is a specification.

In automobiles intended for ordinary road use there are times when it is desirable to coast. This may be owing to a gradient or to a desire on the part of the operator to save energy. In vehicles propelled by steam or com pressed gas as ordinarily constructed the engine is connected to the driving wheel or wheels by suitable mechanical connectionssuch, for example, as worm or spur gearing or sprockets and chain. This construction is satisfactory when the vehicle is being propelled by the engine; but when the power is out oi and the driving wheel or wheels tend to drive the engine there is a considerable friction loss owing to the pistons being dragged back and forth within the cylinders.

The object of the present invention is to overcome the objection above pointed out and to provide means for automatically disconnecting the pistons from the driving mechanism or otherwise render the said mechanism inoperative whenever the vehicle is coasting, or, in other words, whenever the driven element tends to drive the engine, and this without the use of a separate manual controlling device or without thought on the part of the operator.

In the accompanying drawings,which illustrate an embodiment of my invention, Figure l is a longitudinal section of a trunk-engine. Fig. 2 is also a longitudinal section of a trunken gine, showing the crank working independent of the pistons, which occurs when the vehicle-wheels are driving and the engineis not drawing on the source of energy. Fig. 3 represents a four-cylinder engine arranged to impart motion to the driving-wheels. Fig. 4 is a transverse section of the gear-driving mechanism, and Fig. 5 is a partial side View and section of the same.

In the drawings, A represents one cylinder of a trunk-engine, and B the second cylinder.

These cylinders are oppositely disposed, and

` mounted for movement within the cylinders are pistons O and D. The engine is designed to receive hot high-pressure steam or hot compressed gases, which lis admitted through suitable ports. The pistons'are single-acting and are so arranged that at the end of each stroke the exhaust-ports E will be uncovered. If desired, other forms of yvalve mechanism may be employed-for example, that shown in connection with Fig. S-Wherein puppetvalves are used, which are actuated throughmeans driven by the main shaft of the engine, or the same ports may be used for both admission and exhaust. The pistons C and D work through connecting-rods G and H on a common crank F, which is carried'by the main shaft of the engine. These rods are made of two parts which are movable with respect to each other. On account of simplicity `the connecting-rods are shown as being composed of a rod and tube, the former working within the latter. I do not desire to be understood as limiting myself, however, to the telescoping structure shown-that is to say, surrounding one part with another Within which it is capable of moving-since the invention broadly contemplates a twopart loose connection between each piston and the crank-shaft regardless of its precise construction. Considering the specific construction of the connection-rods, the rod-like portion is pivotally secured to the piston, while the tubular portion is connected to the wrist-pin I in the usual manner. Near the inner end ot' each tube is a small opening J, and this, together with the piston and cylinder like structure of the connecting-rods, constitutes a dash-pot for taking up the thrust of the parts and preventing the metallic shocks and hammering which would otherwise occur in placing the parts in operative relation. The opening J also serves to break the vacuum which would exist if the parts of the rod moved vindependent of each other.

' In Fig. l the parts are shown in one of the positions occupied by them when the engine is in operation. In the figure the right-hand piston is in a position to receive steam, while the left-hand piston is shown as uncovering the exhaust-ports E. Steam or other fluid on being admitted to the right-hand cylinder through a throttle-valve and inlet-port forces the piston to the left. Shortly after the start roo the left-hand piston will close the exhaustports, and as the movement continues there will be a compression more or less great of the gas or mixture in the cylinder. The compressed charge in the cylinder will hold the left-hand piston in its proper position with respect to the other. At the end of the stroke the right-hand piston uncovers or otherwise opens the exhaust-port and the ports are in a position to receive steam or gas, but from the opposite end.

Assuming now that the engine-shaft is connected by a suitable mechanical connection with the driving-wheels of a vehicle or to some other device which at times is driven and at other times acts as a driving member and that power is cut off from the engine and the wheels or other mechanism begin to act as driving members, the pistons will be forced to the back ends of the cylinders by the connecting-rods, due to the rotation of the engine-shaft, and will remain until they again begin to drive the main shaft. This is illustrated in Fig. 2. As the crank-shaft turns the tubular portions of the connectingrods will slide back and forth on the rods and the friction loss will be comparatively small,whereas with solid connecting-rods and pistons united thereto, as is the ordinary construction, there is a large relative friction loss due to -the pistons being pulled back and forth in the cylinder, which loss it is the aim of my invention to avoid.

Assuming that the parts are in the position shown in Fig. 2 and that it is desired to start up the engine, the admission-valves being properly set, when one of the connecting-rods is shortened to the limit, or, in other words, the rod and piston are in the position shown in the right-hand end of Fig. I, steam will be admitted through a suitable throttle-Valve to the right-hand cylinder. This will start the engine into operation, and when the crank occupies a position diametrically opposite that of Fig. l the left-hand piston will be in an operative position and the proper valve will open and admit steam. During the interval above referred to the piston and cylinder like structure of the connecting-rods will act as a dash-pot or check and take up the thrust between the left-hand piston and its connecting-rod. After this theoperation is the same as an ordinary two-cylinder engine.

In Fig. 3 my invention is shown in connection with afour-cylindersingle-actin g engine, each piston being provided with a two-part connecting-rod, the parts of which are movable with respect to each other when the vehicle-wheels K tend to propel the engine, but which remain in fixed relation when the engine is receiving` steam or compressed gas and is propelling the vehicle. The admission of steam or other duid to the cylinder is controlled by a series of puppet-valves L, which are actuated by cams M on the engine-shaft, and the exhaust is controlled by the exhaustes4,sss

ing two universal connections R, so that freedom of action is assured. The action of the driving mechanism being the saine as described in connection with Figs. l and 2, the only difference being that four pistons are used instead of two, further description is unnecessary.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. A connecting-rod for an engine, composed of two sections which are free to slide with respect to each other.

2. In a single-acting engine, a cylinder, a piston, a shaft, and a connecting-rod between the piston and the shaft, composed of at least two sections free to slide with respect to cach other.

3. In an engine, the combination of a divided connecting-rod, the parts being free to move with respect to each other, with means for guiding the parts in their movements.

4:. In an engine, the combination of a cylinder, a piston, and a divided connecting-rod, the parts of which are telescoped on each other and are free to move.

5. In an engine, the combination of a cylinder, a piston, a crank, a connecting-rod between the piston and cylinder, composed of portions free to slide with respect to each other, and a device acting to cushion the movements of the parts of the connecting-rod.

6. In an engine, the combination of a cylinder, a piston, a crank, a connecting-rod between the piston and cylinder composed of portions free to slide with respect to each other, and an air-cushion formed between the parts of the connecting-rod for taking up the thrust.

7. In an engine, the combination of a cylinder, a piston, a crank, a connecting-rod between the piston and crank, composed of portions free to slide with respect to each other, a receptacle formed in one of the parts of said connecting-rod, and a piston-like extension formed on another of the parts and arranged to enter the receptacle, the two constituting an air-cushion.

8. In an engine, the combination of a twopart connecting-rod, one part being composed of a tubular structure, the other part being formed of a rod-like structure, and the two arranged to telescope, a receptacle formed at the end of one of the parts, and a piston formed at the end of the other part, and arranged to enter the receptacle, the two forming a dash-pot acting near the end of the independent movement of the parts of the con-fmeeting-rod.

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9. The combination in a vehicle, of singleacting pistons with corresponding connecting-rods made in two sections extensible with respect to each other, a crank and crankshaft driven by the connecting-rods, a Worm driven by the engine-shaft, a worm-gear, and dierential gears connecting the worm-gear to the driving-wheels of the vehicle.

10. The combination of two oppositely-disposed cylinders, pistons therefor acting upon a common crank-shaft, and a connecting-rod between each piston and the crank which is composed of two parts that are free to move with respect to each other when for any reason the crankshaft is driven by extraneous means.

1l. The combination of two oppositely-disposed cylinders, pistons therefor acting upon a common crank-shaft, a connecting-rod between each piston and the crank which is composed of two parts that are free to move with respect to each other when for any reason the crank-shaft is driven by extraneous means, means for causing a slight compression in the end of the cylinder not receiving steam to prevent the idle piston from traveling faster than the active piston, and means for taking up the thrust when the parts of the connecting-rod move independent of each other.

12. In an engine, the combination of oppositely-disposed cylinders, pistons therefor, a common crank, telescoping connecting-rods between the pistons and the cranks, the parts of each rod being capable of moving independent of each other after the manner of a piston and cylinder, and means for breaking the vacuum which would otherwise be formed when one part moved upon the other.

13. In a vehicle, the combination of a single-acting engine, a crank-shaft geared to the wheels of the vehicle through suitable gearing, and an extensible connecting-rod which forms the only connecting medium between the piston and the crank-shaft.

14. In a vehicle, the combination of a single-acting engine having a cylinder and piston, a connecting-rod between the piston and the crank, said connecting-rod being extensible for the purpose described, and a reducinggearing between the engine-shaft and the vehicle-wheels.

15. In a vehicle, the combination of a steam or compressed-air engine having single-acting pistons and cylinders, extensible connecting-4 rods the parts of which are free to move with respect to each other, a worm mounted upon the shaft of the engine, and a worm-gear connected with the vehicle-wheels.

' In witness whereof I have hereunto set my hand this 13th day of November, 1900.

ELIHU THOMSON.

Witnesses:

DUGALD MoKILLoP, HENRY O. WESTENDARP.

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