US 1681494 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Aug. 21, 1928. 1,681,494
W. NOBLE SINGLE ACTING ENGINE AND PISTON Original Filed Feb. 13." 1922 Q r I Patented Aug. 21, 1928.
UNITED STATES PATENT OFFICE.
WARREN NOBLE, OF'DETROIT, MICHIGAN, ASSIGNOR TO N. L. ENGINEERING GOR- POBATION, 0F PROVIDENCE, RHODE ISLAND, A CORPORATION OF YORK.
SINGLE-AGTING ENGINE AND PISTON.
Application filed February 13, 1922, Serial No. 536,036. Renewed November 15, 1927.
The present invention relates to single acting engines and particularly to the pistons used with such engines.
Its objects are to provide for certain forms of engine a piston which will be lighter in weight, cheaper to manufacture, and possess certain superior characteristics over the types heretofore used, and to reduce the height, weight and expense of manufacture of the engine in comparison with previous types of engine of equal power, or to increase the length of connecting rod, other things being equal, in proportion to those of previous engines, or to combine such decreased height, etc., with such increased length of connecting rod, all as the result of the improved construction of piston before referred to and the combination thereof with the engine cylinder.
Another object of the invention is concerned with the lubrication of internal sleeve valves in internal combustion engines and is accomplished by one of the characteristicsof the piston and its combination with the valve, as shown and described in this specification.
The manner and means in and by which the foregoing objects are accomplished, and the characteristics of the piston and engine in which my invention is particularly embodied are best explained in connection with the following detailed description of one such embodiment and the drawings illustrating the same accompanying this specification. Before proceeding to such detailed description, however, I may remark that the invention finds its principal use in internal combustion engines, such as are used for driving motor cars, but that it is not exclusively intended for such use, and my claims are intended to protect the fundamental invention in all uses for which it-may be adapted. Hence it will be understood that although in the drawings furnished herewith I have illustrated an internal combustion engine and have described the invention so illustrated as such a one, the invention is not to be taken as limited otherwise than by its actual novelty in reference to the prior art.
In the drawings v Figure 1 is a fragmentary central section of the head end of one of the cylinders of an internal combustion engine, with my novel piston in place.
, Figure 2 is an axial section of the piston alone taken on a plane at right angles to the plane of section represented in Figure 1.
Figure 3 is an under plan view of the piston alone showing the wrist pin in place and the connecting rod removed.
Figure 4 is in part a top plan view and in part across section of the piston taken on the plane 4-4 of Figure 2.
Although the piston is applicable to an engine having any sort of admission and exhaust valves, yet since one of the novel features which I claim herein has reference to the lubrication of an internal sleeve valve, I have chosen for illustration an engine equipped with such valve. In Figure 1 then, the numeral 6 represents the cylinder of such an engine having a head 7, and both the cylinder wall and head having communicating water jacket spaces 8 and 9, respectively. 10 represents an internal sleeve valve fitting the inner cylinder-wall and within which the piston moves. Such sleeve valve may be of any approved type, but is preferably of the sort disclosed in my prior patent for sleeve valve engines No. 1,38l,401 dated J uly,12, 1921.
It may be assumed with reference to said patent that this sleeve valve is rotated in proper timing with the events of therengine cycle so as to uncover admission and exhaust ports in the cylinder wall (one of which is shown dotted at 11) by registry with such ports from time to time of a port 12 in the sleeve valve.
A spark plug 13, of conventional design, typifies any operative means for igniting a combustible mixture of fuel and air in the cylinder. It is to be understood as to those parts of the engine not here illustrated that the cylinder is open at its crank end and that its opposite sides, above the zone containm g the packing rings, the piston is provide throughout its whole length with surfaces 19 and 20 which fit and have a bearing on the interior of the sleeve valve or of the cylinder. These surfaces I will call slipper surfaces I as for convenience of description merely. The intermediate sides of the piston above the ring zone and between the slipper surfaces are recessedat 21 and and so also the head of the piston recessed at 22' These recesses ill, 22 and :23, respectively, provide volumes which, by proper design of the piston, may be made in total approximately equal to the clearance space heretofore commonly provided in the cylinders of internal combustion engines for the con'iprcssion of the combustible mixture. in other words the piston may run to the head of the cylinder with mininnun clearance between the ends of the slipper surfaces and the cylinder head, and the chan'iber space necessary to hold the compressed combustible mixture is provided by the recesses in the sides and end of the piston.
The intermediate side and end walls of the piston, between the slipper surfaces, ar: appropriately formed, to provide aluitmcnt surfaces or lands 24 and 25 for the extremities of a wrist-pin or piston pin 26, and a central chamber 27 for the central part of the wrist pin and the lutb of the connecting rod. The wrist pin :26 is cut away on one side at each of its opposite ends to approximately' an axial plane. The flat seats so formed on the pin ends are adapted to bear on the abutment surfaces 24 and or preferably on washers 28 laid against said abutments for a purpose presently described. Holding bolts 29, 30 are passed through registering holes in the pin ends and in the abutment shoulders of the piston and have heads 31 resting on eX- ternal fiat abutment surfaces formed opposite to the inner shoulders 24 and Holding and locking nuts 32 are screwed on the ends of the bolts inside the piston.
The middle part of the wrist pin occupies the chamber 27 and tits within the hub 33 of the connecting rod 14.
The pointed projection 34 on the inncr surface of the cylinder head and the s in the adjacent side of the connectin l hub are provided for lubricating the w t pin, as the oil splash gathering in the piston head is caused to drip from this projection into this slot.
The piston is made as a casting, yu'c'l erahiy of ametal or alloy which is light in weight. such asalun'iinum or an alloy of that metal. The wrist pin is preferably of ste l, and preterably also it is centrally bored from end to end to reduce its weight. It may he made of relatively very large diameter and thereby the pressure exerted on the cormccting rod is distributed. By reason of its tabular form, however, its bearing area on the piston is limited to relatively narrow zones. wherefore the washers 28, which are made of hardened sheet steel, are interposed between the sides of the pin and the abutment shoulders of the piston in order to prevent the narrow hearing 1 lot 05 areas of the pin from cutting and wearing deeply into the soft metal of the piston casting. buch wear as does occur between the pin and the washers can be readily taken up by tightening the nuts on the holding bolts.
This design and construction of piston has a number of conspicuous advantages, both in regard to the piston itself and to the association of the piston with a cylinder and with a sleeve valve in the cylinder. 151;, the piston can be cast in green sand without the use of cores, which is important from the standpoint of manufacttu'ing cost. 2d, the piston may be as embled with the wrist pin and connecting rod most conveniently and iptickly; and in the case of large engines can be disassembled, without necessity of stripping the engine, by removing the holding nuts, which are accessible from the open crank end of the cylinder, and withdrawing the piston body from the crank pin. 3d, the facts that the wrist pin is confined entirely within the piston, that is, is nohcxposed at its ends in the outer walls of the piston, and that the holes in the piston through which the attached bolts pass are closed tightly when the nuts on these bolts are tightened up, prevents leal-zage of the working tluid around thc pin. ith. the location of the packing rings at the lower end of the piston is etl'cctivc to prevent liooding of the combustion chamber by lubri rating oil and. if the lowermost land of the piston made of small diameter, it enables the bottom ring to act eliicicntly as an oil scraper, preventing oil from \vorkiir; in too large quantities past the rings and avoids the nect sity of auxiliary grooves and passages common with prior types of pistons for conducting away surplus oil. 5th, the location of the wrist pin above the piston rings and also above the longitudinal middle of the piston is conducive to smoother running and less \vcar between the piston and cylinder andv enables the piston to be made shorter than has been necessary heretofore. 6th, the last named characteristic, coupled with the elimination of clearance space in the head of the cylinder, enables an engit'ie of given power and length of stroke to be built with less height than heretofore; and the connecting rod may be made of greater length, thus improving the balance of the engine. 7th, the slipper surfaces running almost to the head of the cylinder are able to overrun the end of the sleeve valve, when the cylinder is equipped with a rotating sleeve valve, and in so overrunning these surfaces carry oil past the edge of the valve, which scrapes off some of the oil him on the slipper surfaces, whereby necessary lubrication for the upper end of the sleeve valve is provided. 8th, the seating surfaces 24; and 25 may be located and finished by milling, accurately and readily by well UD(lC1Il0O(l machine shop methods; and the pin is thereby accurately located centrally with respect to the slipper surfaces. 9th,
since the slipper surfaces are above the ring zone, the heat transferred from those parts of the piston'to the cylinder walls does not have to travel past the rings, and from this 'it results that the metal back of the rings can be lighter and that the rings themselves work under more favorable conditions.
All the advantages due to the recessing of the piston sides are obtained without sacrifice of essential bearing area because the slipper surfaces have ample width of bearing to sustain the reaction thrust of the connecting rod Without excessive wear, either of their own surfaces or of the cylinder wall, or of the sleeve valve when such a sleeve valve is used.
Certain of the above described characteristics of the piston may be used in structures from which other of such characteristics are omitted and, therefore, I wish it to be understood that my claim to protection is not limited to the combination of all these characteristics .in one structure, but includes said characteristics severally and in combination with others, less than the whole number, in any association where such individual characteristics and partial combinations may be used within the scope of the appended statements of claim.
In this specification such terms as indicate relative height and position are used descriptively with reference to the drawing and without intent to limit the invention in any wise as to the position in which a piston and engine embodying the invention must be used. All such terms are to be broadly construed with substantially the following significance, namely, that the upper end of the cylinder is the head end and the upper end of the piston is the end nearer the cylinder head, while the terms indicating lower position are to be construed as meaning parts more remote from the cylinder head, whatever may be the position in which a specific embodiment of the invention is arranged.
It is to be noted further that various modifications in the construction of the piston may be made within the scope of the protection hereinafter claimed. Specifically the location of the piston head or transverse Wall with relation to the extremities of the piston may be changed from that here shown and so also may its external contour, as well as the position and contour of the external recesses which provide a clearance or compression space. The precise design of these features in any particular case is determined by the volume necessary for the compression space and the length and bearing area of the wrist pin necessary to carry the piston thrust. iteferrine to the detail. of the washers 28, it may be noted that these washers may be omitted where conditions warrant, but when they are used they are to be construed, for the purposes of this specification, as essentially parts of the shoulders 24. and 25 within the piston against which the ends of the wrist pin abut.
What I claim and desire to secure by Letters Patent is:
1. The combination with a cylinder of a piston having opposite slipper surfaces bearing on the walls of the cylinder and spaces intermediate such slipper surfaces adjacent one end thereof adapted to contain fluid confined between the piston and the head of the cylinder.
A piston having a zone adjacent to one end constructed and adapted to carry packing rings, and having a slipper surface on one side at its opposite end adapted to bear on the wall of the cylinder in which the piston works, the piston also having an external recess beside said slipper surface and above said ring carrying zone.
3. A piston having a zone constructed and arranged to carry packing rings adjacent to that end which is directed toward the crank of the machine in which the piston is used, said piston having a hollow interior open at the same end and a wrist pin secured in such hollow interior relatively remote from said end, the piston having a lateral bearing surface and an adjacent external recess at its opposite end, together with atransverse closing wall.
at. In a piston having a hollow interior open at one end, and a transverse wall remote from said open end, which wall is provided with abutment shoulders, a wrist pin contained wholly within the piston and bearing adjacent to its ends against said abutment shoulders, and means for securing the end portions of the pin to said shoulders; the piston being formed with external slipper surfaces at opposite sides of the wrist pin axis, and with external spaces between said slipper surfaces to contain compressed working fluid.
5. A hollow piston open at one end and having a head formed with a central part oil'- set from said end and with abutment shoulders at opposite sides of said offset part, a wrist pin located wholly within the piston, with its end portions bearing against said abutment. shoulders and its central portion crossing the cavity within said offset part of the head, and fastening means securing the end parts of said pin to said shoulders; the piston being formed with external slipper surfaces at opposite sides of the wrist pin axis, and with external spaces between said slipper surfaces to contain compressed working fluid.
(5. A piston formed with a hollow interior open at one endand a head which is offset in its central part away from said open end, said head. having abutment shoulders at opposite sides of said offset part, said piston raving an external segn'iental slipper surface of which the central element is in an axial plane perpendicular to the median plane of at each side of the slipper surface providing said shoulders, a wrist pin constructed to bear a space 01' sufiicient volume to contain a com- 1 at its ends against said shoulders and having pressed charge of a combustible mixture and bearing surfaces coinpleniental thereto, and having a complete cylindrical zone surround- 5 fastenzng means located in the axial plane of lag said open end.
the piston perpendicular to the median plane In testimony whereof I have allixed my of the slipper surface for securing said wrist signature. pin, the exterior of the piston being recessed \VARR-EN NOBLE.