US1993997A - Piston spreader - Google Patents

Description

March 12, 1935. Q JQHNSQN 1,993,997

PI S'ION SPREADER Filed July 21, 1934 hven'tov Chafles 'Edoh son 44 M ATrorne. g

Patented Mar. 12, 1935 UNITED STATES.

PATENT OFFICE 5 Claims.

This invention relates to piston expanders or Spreaders.

Lightweight pistons, made from aluminum alloys, are used in very considerable quantities in internal combustion engines in motor vehicles. Such pistons are subject to wear and the coefilcient of expansion of the metal used differs from the metal of the cast iron cylinder block so that irrespective of how perfect the piston may work in an engine when the engine and pistons are new, it very frequently occurs that after a period of use the piston becomes loose in the cylinder to a greater extent than is desirable, resulting in piston slap from looseness of the lower end of the piston with respect to the cylinder. Also in 'many cases there is oil pumped and loss and waste of lubricating oil at the upper portion of the piston, particularly after the piston rings,

- which are around the upper end of the piston,

have become considerably worn.

The correction of the trouble at the upper end of the piston by the installation of new piston rings is well known. Such correction as to oil pumped and waste of lubricating oil does not aid in overcoming the troubles due to wear at the lower end or skirt of the piston. In many cases it has been common to rebore the cylinders and replace the pistons with oversize pistons to fit said larger rebored cylinders, and supply new rings for such larger pistons. Or instead of reboring the cylinders in some cases the cylinder block has been entirely replaced. Either is very expensive.

With my invention, by means of a very simple and practical expander applicable at the inner sides and near the lower end of the piston skirt, the piston can be properly expanded or enlarged so as to compensate for wear in the piston and cylinder walls. Then when an internal combustion engine is to be reconditioned, the replacement of the piston rings and the addition of the piston expander of my invention places the engine, insofar as cylinders and pistons are concerned, again in substantial perfect condition and at a relatively very low cost. r The invention and a preferred structure embodying the same will be understood from reference to the following description, taken in connection with the accompanying drawing, in which, 7

Fig. 1 is a vertical'section through a piston equipped with theexpander or spreader of my invention.

Fig. 2 is a horizontal section through the piston showing the expander of my invention in plan,

one part thereof being longitudinally sectioned for clearness of disclosure.

Fig. 3 is a fragmentary enlarged transverse section on the line 33 of Fig. 2, and

Fig. 4 is a fragmentary vertical section on the line 44 of Fig. 2. ,1

Like reference characters refer to like'pa'rts in the differentfigures of the-drawingfl The piston 1, usually of an aluminum alloy, for the application of the expander of my inven- 1 tion is slotted at one side as indicated at 2. Many pistons of the light weight, aluminum alloy character have this slot when manufactured. Others have a slot extending nearly to the lower edges of the piston in which case it is necessary merely to continue the slot to the lower edges of the piston. In preparing the piston for the installation of my invention a continuous shallow groove 3 is. made at the inner side and near the lower end of the piston as shown, that is, the groove is at the inside of the depending skirt of the piston.

The expander or spreader of my invention includes four parts. Two of them are duplicates consisting each of a body 4 made of a length of rod preferably hexagonal in cross section. At one end the rod is interiorly drilled and threaded as indicated at 5. At the other end it is drilled inwardly for a short distance, there being left an integral cross web 6 between the inner ends of the two holes which are drilled inwardly from the ends of the body member'4. This is fully shown in Fig. 2.

Another member of the structure is made up into substantially U-shape from a length of stiff 35 wire rod and consists of a cross portion '7 having a curvature such that it substantially fits the curvature of the groove 3 in the piston, and from each end of which legs 8 project. These legs 8 are threaded so as to enter the threaded openings 5 in the body members 4 previously described. The two members 4 may be readily threaded onto the ends of the legs 8 in the assembly of the construction.

The remaining member of the structure is formed of spring wire rod having a curved intercircumferentially moreor less as desired. Secmore than three.

ond, they provide resiliency whereby expansion and contraction of the piston may occur.

In practice preferably the piston, diametrically opposite the slot 2, and in the plane of the groove 3 will have a small opening 13 drilled therethrough. The part 7 at its outer side is formed with a projecting lug 14 to enter such opening, thereby locating the expander in the piston and holding it against movement.

It will be noted with reference to Fig. 3 that the connecting portions between the spring members and 11 bear against flat sides of the hexagonal body members 4. This provides a substantial lock to hold such members 4 against any tendency to move and either thread inwardly or outwardly on the legs 8. But by applying a proper wrench to the members 4 the spring material from which the member is made yields sufficiently that the expander may be adjusted at both sides to properly and snugly engage the groove 3 made in the piston.

With this construction the expander may be located within the piston freely, that is, with the members 4 threaded onto the legs 8 a sum-- cient distance so as to bring the two opposing sides 7 and 9 of the expander toward each other sufiiciently that the expander may be very readily and easily placed within the piston. Then by applying the wrench to the members 4 and turning the same so as to screw the same outwardly on the legs 8 the opposed bearing portions 7 and 9 are moved away from each other and press against the bottom of the groove 3, fit the same snugly and expand the piston to the desired degree.

When the piston is equipped with the expander and the expander properly adjusted the lower end or skirt portion of the piston thereupon is properly enlarged to compensate for any wear which has taken place in either the walls of the cylinder or on the outer sides of the piston skirt. The member consisting of the parts 9, 10, 11 and 12 being-of yielding spring material, if a portion of the length of the cylinder is worn greater than another portion this yielding spring member will yield or expand as may be necessary to take care of such difierences in diameter of the cylinder.

The piston expander or spreader of my invention is economical to make, very quickly and easily installed and is particularly effective in service. An internal combustion engine, so far as pistons and cylinders are concerned, is very quickly and economically reconditioned through the replacement of the worn piston rings with new rings and the addition of the expander of my invention to the lower end or skirt of the piston as described. Or if the rings are not worn so as to need replacement when piston slap develops, the expander alone may be installed.

One very good feature of the present invention is that any particular size of piston expander made in accordance with my invention is applicable to quite a number of pistons having different diameters, so that for substantially the sizes of pistons used in automotive engines it will not be required to make more than a very few standard sizes of piston expanders, probably not The spring character-of the bearing portion 9 will permit it to conio'rmto grooves in pistons 'of different diameters within a limited range, while the adjustment. permitted by the threaded connection of the body members 4 on the legs 8 allows for adaptation of the expander to several sizes of pistons within a range between the largest and smallest in diameter of one-half inch or more, without affecting the beneficial results obtained.

The invention is defined in the appended claims and is to be considered comprehensive of all forms of structure coming within their scope.

I claim:

1. A piston expander comprising, two spaced apart body members longitudinally drilled and threaded at one end and having longitudinal openings drilled therein at the other end, providing stops between the inner ends of said openings, a member of spring material having a curved intermediate section and formed at each end into reversely bent spring loops and terminating in end portions received within said second mentioned longitudinal openings and engaging against said stop, and a member having a curved intermediate portion and threaded end portions adjustably received within said threaded openings of the body members.

2. A construction containing the elements in combination defined in claim 1, said body members each having a plurality of flat sides against which said spring loops bear to yieldingly hold I the body members against turning movement.

3. A piston expander comprising, a member of spring wire having a curved intermediate portion with reversely bent spring loops at the ends of said intermediate portion, said loops having terminal end portions parallel to each other, two members each having longitudinal openings therein into which said terminal portions of the first member are inserted to bear against the bottoms of said openings, and an additional member upon which both of said second mentioned members are adjustably mounted, whereby said additional member and spring member may be adjusted inwardly or. outwardly with respect to each other.

4. A piston expander comprising, two elongated body members of predeterminedcross section and' surface, each longitudinally drilled and threaded inwardly at one end for a distance, and longitudinally drilled or cored at the other end, the longitudinal openings in each body member terminating short of each other, a member having threaded terminal end portions onto which the body members are threaded, an additional member of spring material having an intermediate curved portion and parallel end portions, said end portions being received in the second of said longitudinalopenings and seated at their ends against the bottoms of said openings, and means on said last mentioned spr'ng member adapted to yieldingly engage the sur ace of each of the body members to yieldingly hold the same against turning movement.

'5. A piston expander of the class described comprising, two spaced apart body members each having a threaded opening and a second opening, a substantially U-shaped member having a curved intermediate section and threaded legs on which said body members are adjustably second openings in the said body members, as and for the purposes described.

L CHARLES E. JOHNSON.

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