US1720625A - Engine casing - Google Patents

Description

y 1929. A. E. L. CHORLTON 20.62

ENGINE CASING Filed July 1; 1925 3 Sheets-Sheet l July 9, 1929. A. E. L. CHORLLTON ENGINE CASING 3 Sheets-Sheet Filed July 1925 Y JVV/ awe/170 July 9, 1929. A. E. L. CHORLTON ENGINE CASING Filed July 1, 1925 I5 Sheets-Sheet KL T Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

ALAN ERNEST LEO FBIC CHORLTON, OF LONDON, ENGLAND, ASSIGNOB OI ONE-HALF TO WILLIAM BEARDMOBE, OF LONDON, ENGLAND. I

ENGINE casme.

Application filed July 1, 1925, Serial No. 40,927, and in Great Britain July 9, 1924.

K This invention relates to the bed or casing of a high speedlight weight prime mover, such for example as an internal combustion engine used for the propulsion of air-craft. Such casings are usually formed relatively thin and are constructed of a material having a low specific gravity with the result that the casings are liable to crack when subjected to the stresses set up by the operation of the engine more particularly in the neighborhood of the crank shaft.

One object of the present invention is to provide means whereby the casing of such an engine may be strengthened so as to enable it to withstand the heavy internal loads set up by the rotating parts.

A further object is to provide improved supporting means for the crank shaft.

A further objectis to provide improved means for withstanding the tensile stresses in the casing.

Further objects will be apparent from the following description and claims.

The invention may be carried out in various ,ways but a convenient construction according thereto is illustrated by way of example in the accompanying drawings as applied to the casing of an internal combustion engine havingfour cylinders in linewith one another. It will be understood, however, that the invention is applicable to engines having other arrangements of cylinders. In these drawings, a

Figure 1 is a vertical longitudinal section through the axis of the engine crank shaft.

Figure 2 is a section onthe line 22 of Figure 1,

Figure 3 Figure 1,

Figure i is a perspective View of part of one of the vertical stays, and

Figure 5 is an enlarged perspective view of a part of the upper portion of one of the crank shaft bearings.

In the construction illustrated in the drawings the whole engine casing consists of a single casting comprising two longitudinal side walls A, A two transverse end walls B, B and three transverse webs or walls C, C, C which serve to separate the cylinders and the crank chambers from one another.

The casing is conveniently formed of a material of low specific gravity, for example, aluminum or aluminum alloy. This material is given by way of example only, and it is is a section on the line 33 of to be understood that any other suitable material may be used.

Each of the side walls A terminates at its lower edge with a portion D of box section, the box girder thus formed having such design in plan, as may be seen from Fig. 3, that the outer margins are convexed outwardly or diverged from both ends toward the middle. By way of illustration, the girder D is shown closed on all four sides (apart from the holes necessary for casting purposes). An opening E, nomally closed by a cover plate, is provided in the side wall of each crank chamber, this opening being large enough to permit the inspection or removal of the piston and connecting rod.

Each of the transverse webs or walls C is also provided at its lower edge with a portion F of box section. The transverse box girders F thus formed extend through the side walls A and join at their ends with the longitudinal box girders D. Each girder F is recessed at G on its lower side to form the upper portion of a crank shaft bearing and is also provided with projecting ribs H, H clearly shown in Figure 5 which form keys for the reception of the lower bearing cap J. The lower bearing cap J is held to the upper portion of the bearing formed in the box girder F by means of bolts passing through bosses K and the ribs H, H serve to key the bearing cap in two directions to the girder F, thus further strengthening the arrangement.

The two transverse end walls B are similarly provided at their lower edges with portions L of box section, the whole walls with their box girders being shaped to suit the auxiliary apparatus to be fitted to the engine casing at its ends. These box girders L are provided (like the girders F on the transverse diaphragms) with recesses M and key ribs N, O to accommodate the lower portions of bearings for the crank shaft, and they are also connected at their ends to the longitudinal box girders D.

As has been mentioned, the whole engine casing is formed as a single casting and thus constitutes an integral cellular unit of great strength. The longitudinal box girders are provided with bolt holes P which receive the bolts by which the oil sump is held to the bottom of the casing. These bolt holes P are disposed adjacent to'the ends of the transverse box girders F.

, walls and diaphragm plates above the plates- The walls A and B and the webs C also serve to carry the cylinders and are provided for this purpose with horizontal diaphragm plates Q, R having circular holes therem.

The'spaces between the cylinders and the provided adjacent to each transverse girder F while two stays are disposed adjacent'to each of the two end crank shaft bearlngs as clearly shown in the drawings. The ends of the stay bolts conveniently pass through sockets in the girders D. These stay bolts are formed of a material having a high tensile strength as compared with that of the material of which the casing is formed, for example of high tensile steel, or other suitable material.

Vertical stays are also provided connecting the crank shaft hearings in the girders F to the heads U of the cylinders. Each of these vertical stays comprises four vertical short bolts V the lower ends of which pass through the bosses K in the sides of the crank shaft bearings and are provided with thrust nuts V by means of which the lower half J of the bearing is held in position while their upper ends pass respectively through the ends of two longitudinal connecting pieces V which are disposed in bores in the girders F as 7 shown in Figure 4. Each of the longitudinal connecting pieces V is connected substantially at its centre to a long staybolt V which passes through a vertical bolt hole formed in the web C and is connected at its upper end to a cross bar W through which the tension in the stay bolts V is transmitted to the cylinder heads U.

From the foregoing, it will be apparent that I have devised an engine frame construction, which, for the weight of material employed, possesses a high degree of strength. The frame resists deflection in all directions, this result being assisted by the form of base construction consisting of box girder members integral with the lower edges of the sides, ends, and the intermediate webs, all

of the box girder members being integrallyjoined together. Owing to the fact that the longitudinal girder members diverge .ontwardly from the ends of the engine construc tion toward the middle thereof regarded in a plane normal to the plane of the cylinder axes, a construction is provided which resists deflection laterally, or in a plane normal to the plane of the cylinder axes; and it will be obvious that the form of construction of the frame is stiff in all other planes. The outward convexity of the side girders results in the latter increasing in width from the ends toward the centers thereof, that is, the section modulus, of each side girder increases from the ends toward the center. Also, the base construction; consisting of side girders and the transverse connecting elements, may be regarded as a structural member whose section modulus increases from the ends toward the center. These features of construction make it possible'to dispose the metal in' a most advantageous way to resist whipping or unbalanced centru'ugal forces normally tending to displace the crank shaft bearings and deflect the frame.

It will be understood that the arrangement more particularly described and illustrated has been given by Way of example only and that modifications may be made without departing from the scopeof the invention.

What I claim as my invention and desire to secure by Letters Patent is 1. In an engine, the combination of a casing adapted to carry the cylinders and including longitudinal and transverse Walls forming chambers for enclosing the cylinders, and girders of box section formedintegrally with the lower edges of the longitudinal walls and having their outer margins divergent from the ends toward the middle. i

2. In an engine, the combination of a casing adapted to carry the cylinders and including longitudinal and transverse walls forming chambers for enclosing the cylinders, girders of box section formed integrally with the lower edges of the longitudinal walls and having their outer margins divergent from theend toward the middle, and a transverse girder of box section joined to the longitudinal girders.

3. In an engine, the combination of cylinder heads, a casing adaptedto carry and to enclose the cylinders and including longitudinal side walls, transverse girders of box section formed integrally with and connecting the lower edges of the side walls, crank shaft bearings carried by the girders, and stays .formed independently of said casing for resisting working forces applied to the crank shaft bearings and to the cylinder heads. 4. In an engine, the combination of cylinder heads, a casing adapted to carry the cylinders and including longitudinal and transverse walls forming chambers .for enclosing the cylinders, girders of box section formed on the lower edges of the longitudinal walls, crank shaft bearings carried by the transverse walls, and stays cooperating with the cylinder heads and with the-crank shaft bearings to resist engine working forces applied thereto. I

5. In an engine, the combination of'cylindcr heads. a casing adapted to carry the cylinders and including longitudinal and transverse walls forming chambers for enclosing the cylinders, girders of box section formed on the lower edges of the longitudinal walls,

transverse girders of box section formed on the lower edges of the transverse walls, the longitudinal and transverse girders being joined together, crank shaft bearings carried by the transverse girders, and stays cooperating with the cylinder heads and the crank shaft hearings to resist engine working forces applied thereto.

6. A casing for a multi-cylinder internal combustion engine formed of a material hav ing a low specific gravity and comprising integral longitudinal and transverse walls. transverse girders of box section connecting the lower edges of the longitudinal walls at intermediate points in their lengths and transverse stays connecting the lower edges of the longitudinal walls ad acent to thetransverse girders and formed of a material having relatively high tensile strength.

7. A multi-cylinder internal combustion engine including in combination, a casing formed of a material of low specific gravity and comprising integral longitudinal and transverse walls, crank shaft bearings carried by the transverse walls, cylinder heads, vertical stays connecting the crank shaft hearings to the cylinder heads of the engine, and transverse stays connecting the longitudinal walls at intermediate points in their lengths, the vertical and transverse stays being formed of a material of relatively high tensilelstr-ength. 7

8. A casing for an internal combustion engine comprising longitudinal and transverse walls, girders of box section formed on the lower edges of the longitudinal walls such girders having their outer margins divergent from the ends toward the middle, at least one transverse girder also or" box section connecting the longitudinal girders and transverse stays connecting the longitudinal girders adjacent to each transverse girder and formed of a material having relatively high tensile strength.

9. A multi-cylinder internal combustion engine including in combination, a casing formed of a material of low specific gravity and con'iprising integral longitudinal and transverse walls, girders of box section "formed on the lower edges or" the longitudinal walls, cylinder heads, crank shaft bearings'carried by the transverse walls, vertical stays connecting the crank shaft hearings to the cylinder heads of the engine, and transverse stays connecting the longitudinal walls adjacent to the transverse Walls, the vertical and transverse stays being formed of a material having relatively high tensile strength.

10. A multi-cylinder internal combustion engine including in combination, a casing formed of a material of low specific gravity and comprising integral longitudinal and transverse walls, girders of box section formed on the lower edges ofthe longitudinal and I transverse walls, cylinder heads, crank shaft bearings carried by the transverse girders, vertical stays connecting the crank shaft bearings to the cylinder heads of the engine, and transverse stays connecting the longitudinal girders adjacent to the transverse gird ers, the vertical and transverse stays being formed of a material having a relatively high tensile strength.

11. A multi cylinder internal combustion engine including in combination a casing formed of a material of low specific gravity and comprising integral longitudinal and transverse walls, crank shaft bearings carried by the transverse walls, cylinder heads, and verticalstays connecting the crank shaft bearings to the cylinder heads of the engine and formed ofa material having relatively .high tensile strength, the vertical stays comprising four vertical bolts connected to each bearing member, two connecting pieces with the ends of which the bolts respectively engage and a rod extending substantially from the centre of each connecting piece and connected at its upper end to the cylinder head as set forth. V

12. A multicylinder internal combustion engine including in combination a casing formed of a material of low specific gravity and comprising integral longitudinal and transverse walls, girders of box section formed on the lower edges of the longitudinal walls, cylinder heads, crank shaft bearings carried by the transverse walls and vertical stays connecting the crank shaft bearings to the cylinder heads of the engine and formed of a material having relatively high tensile strength, the vertical stays comprising four vertical bolts connected to each bearing member, two connecting pieces with the ends of which the bolts respectively engage and a rod extending substantially from the centre of each connecting piece and connected at its upper end to the cylinder head as set forth.

13. A multi-cylinder internal combustion engine including in combination a casing formed of a material of low specific gravity and comprising integral longitudinal and transverse walls, girders of box section formed on the lower edges of the longitudinal and transverse walls, cylinder heads, crank shaft bearings carried by the transverse girders and vertical stays connecting the crank shaft hearings to the cylinder heads of the engine and formed of a material having relatively high tensile strength, the vertical stays comprising four vertical bolts connected to each bearing member, two connecting pieces with the ends of which the bolts respectively engage and a rod extending substantially from the centre of each connecting piece and connected at its upper end to the cylinder head as set forth.

14. A casing for a multi-cylinder internal combustion engine formed of a material having a: low specific gravity and comprising integral longitudinal and transverse walls,

transverse girders ofbox section connecting the lower edges of the longitudinal walls at intermediate points in their lengths and having relatively high tensile strength, the.

transverse stays comprising four bolts adjacent to each transverse girder two of which ass above and two below the crank shaft earing. I

15. A multi-cylinder internal combustion engine including in combination, a casing formed of a material of low specific gravity and. comprising integral longitudinal and transverse walls, girders of box section formed on the lower edges of the longitudinal and transverse walls, crank shaft bearings carried by the transverse girders, cylinder heads, vertical stays connecting the crank shaft bearings to the cylinder heads of the engine and comprising four vertical bolts connected to each bearing member, two connecting pieces with the ends of which the four bolts respectively engage and a bolt extending 1 from substantially the centre of each connecting piece and connected atv their upper ends to the cylinderheads, and four transverse stay bolts connecting the longitudinal girders at points adjacent to the transverse girders two of these bolts passing above and two below the crank shaft bearing, the vertical and transversestays being formed of a material havin a relatively high tensile strength.

16. In an engine, the combination of a casing including a top wall having apertures through which the cylinders are adapted to depend and including joined longitudinal and transverse walls joined at their upper edges to the top wall and forming chambers for enclosing the cylinders, and box girders formed integrally with the lower edges of the transverse walls.

17. In an engine, the combination of a casing including a top wall having apertures through which the cylinders are adapted to depend and including joined longitudinal and transverse walls joined at their upper edges to the top Wall and forming chambers for enclosing the cylinders, and girders of box section formed mtegrally with the lower edges of the longitudinal and of the transverse walls, said girders being integral with one another.

18. In an engine, the combination of a casing formed of material of low specific gravity and comprising a top wall having apertures through which the cylinders are adapted to depend and including integral longitudinal and transverse walls integral with the top wall, said longitudinal and transverse walls forming chambers for enclosing the cylin-,

ders, cylinder heads, longitudinal girders of box section formed integrally with the lower edges of the longitudinal walls, girders of box section formed integrally with the lower edges'of the transverse walls and integrally connected to the longitudinal girders, crank shaft bearings carried by the transverse girders, stays cooperating with the cylinder heads and with the crank shaft bearings to resist engine working forces, and transverse stays connecting the longitudinal girders and -.ing adapted to carry and to enclose the cylinders and including longitudinal walls; lon-' gitudinal girders of box section having their inner upper corners formed integrally with the lower edges of the longitudinal walls; and transverse girders of box section formed integrally with the longitudinal walls, extending through and beyond the latter, and having their outer ends formed integrally with the top portions of the longitudinal girders.

21. In an engine, the combination of cylinder heads, a casing adapted to carry and to enclose the cylinders and including longitudinal walls; girders of the box section formed integrally with the lower edges of the longitudinal walls; transverse girders of box section formed integrally with the longitl dinal walls, extending through and beyond the latter, and having their outer ends formed integrally with the top portions of the longitudinal girders; crank shaft bearings carried by the transverse girders; tension rods cooperating with the cylinder heads and with the crank shaft bearings to resist engine working forces applied thereto; and tension rods arranged above and below the axis of the crank shaft bearings and adjacent to the transverse girders and having their ends extending through the longitudinal girders and means arranged beyond the longitudinal girders and cooperating with the latter and with the outer ends of said lastnamed tension rodszfor placing the latter under tension.

22. In an engine, the combination of a casing adapted to carry the cylinders and including longitudinal and transverse walls forming chambers for the cylinders, longitudinal girders of box section integrally formed with the lower edges of the longitudinal walls, transverse girders of box section integrally formed with the longitudinal walls portions of the said longitudinal and girders, the outer margins of said longitudinal walls and girders, the outer margins of said longitudinal girders diverging from the ends toward the center whereby said longitudinal and transverse girders form a structural member whose section modulus increases from the'ends toward the center, and crank shaft bearings carried by said transverse girders.

23. In an engine, the combination of cylinder heads, a casing adapted to enclose the cyl inders and including longitudinal and trans:

verse walls forming chambers for the cylinders, longitudinal girders of box section formed integrally with the lower edges of the longitudinal walls, girders of box section formed integrally with the lower edges of the transverse walls, and with the longitudinal girders, crank shaft bearings carried'by the transverse girders, tension rods cooperating with the crank shaft bearings and with the cylinder heads to resist engine working forces, and transverse tension rods connecting the longitudinal girders and arranged adjacent to said transverse girders.

In testimony whereof I have signed my name to this specification.

ALAN ERNEST LEOFRIC CHORLTON.

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