US2115304A - Piston expander - Google Patents

Description

April 26, 1938. J. B. EVANS PISTON EXPANDER Filed March 27, 1957 11 arty/M 4.

Patented Apr. 26, 1938 uNiTEo [STATES h rrs'ron ExPAnDEn 7 James B. Evans; South Williamsport, Pa. Application March 27, 1937', Seriai No. 133,431

7 Claims. (01.. 309-12) My invention relates to animprovement in piston expanders.

After an automobile engine has been used for a period of time, the cylinder walls wear somewhat and also the wrist-pins of the pistons Wear, and as a result a knock which is generally known as a piston slap develops. In order to correct this piston slap, it is necessary either to replace the pistons with new pistons or to expand the skirt of the old piston so that it will follow the cylinder wall more closely. It has been found that by expanding the piston skirt, very satisfactory results may be obtained incorrecting piston slaps by again making the skirt properly fit within the cylinder, so that it may reciprocate therein without knockingv on the side walls at the top of the piston stroke.

An object of my invention is to provide a'piston expander which may be readily adjusted to expand the piston skirt within one-thousandth of aninch or less.

A further object is to provide a piston expander which may be placed within the skirt of a conventional aluminum-alloy or steel-alloy piston or any other piston in position so that after the expander has been adjusted, it may not be shaken loose and drop from the piston.

A further object is to provide a piston expander which will expand a piston skirt equally on both sides of the customary slot through the skirt.

In the accompanying drawing:

Fig. 1 is a front elevation, partly in section showing my piston expander in place within the piston skirt;

Fig. 2 is a side elevation partly in section showing the piston expander;

Fig. 3 is a bottom plan view; and

Fig. 4 is a disassembled view showing the several parts of the piston expander, one part being broken away.

A conventional piston 2 is provided with a slot 4 in the skirt thereof, or which may be cut in the skirt if it is not provided in the piston as a part of the regular equipment. The piston is also provided with customary bearing 6 to hold a wrist-pin passing therethrough and through the upper end of a connecting-rod (not shown).

The bearing 6 is provided with conventional shoulders 8 and H] on the inside of the piston, which shoulders are primarily a part of the casting from which the piston is made, and to provide a suitable base for the bearing 6.

In preparing a piston for the use of my piston expander, I drill two substantially small holes through the piston skirt near the lower end thereof approximately beneath the bearing 6 and diametrically opposite one another. These holes. maybe of any suitable size, but must be approximately of the "-"same -diameter' as the diameter of the 'steel' wire which I bend and utilize to make my piston expander. The steel wire part oi the piston expander is provided with an end II which is sharply bent and is adapted to fit within the holes which have previously been bored in'the lower portion of the piston'skirt. The steel wire from this'point extends approximately straight, and this straight portion H-covers approximately the distanceof an arc of thirty degrees (30) at which point IS the steel wire is bent atan angle from the straight portion 14 and extends approximately straight from the angle [6 to anotherangle l8 of approxi mately the-same'degree as the angle 16, from which angle the wire extends straight for a short distance, and is. provided with suitable screwthreads 20.

Another wire, which is identical in itsv configuration is'utllized to extendfrom the other hole which has been bored in the piston skirt 3. After these two portions of the expander have been placed in the diametrically opposite holes, and

suitable nuts 22 have been threaded on to the screw-threaded ends 20, a collar 24 is placed over the screw-threaded ends 20 in position to be engaged by the nuts 22 when they are turned.

These two steel wires or bent pieces as described above, and as clearly disclosed in Fig. 3; are placed within the piston skirt and forced inwardly toward the head of the piston until the straight portion l4 abuts against the shoulder 8 and the straight portion I'I between the bends l6 and I8 abuts against the shoulder l0 within the piston skirt. This abutting relation between the shoulders 8 and I0 and the straight portions I4 and [l prohibits the. piston expander from being moved to a point further within the piston.

By turning the nuts 22 to bear against the collar 24, the screw-threaded ends 20 and consequently the steel wire portions of the expander are forced outwardly and push against the piston skirt 3 at the points where the bent portions 16 and I8 bear against the skirt 3. In this way, the piston skirt 3 may be forced outwardly, the slot 4 consequently being widened as the other portion of the skirt is expanded to a predetermined amount.

By the position which they assume within the piston skirt, the nuts 22 bear against the inside of the piston skirt so that they will remain locked number of thousandths of an inch, so that it will again fit properly within the cylinders. I

utilizing hexagonal nuts 22, I have found that a' one-sixth turn of either or both of these nuts is satisfactory in expanding a piston the desired amount. Obviously, if a finer adjustment should be desired, octagonal nuts or nuts having even;

more fiat surfaces could be utilized and yet could be properly locked by abutting against the skirt of the piston. r V

, -I claim:"

LA piston expander including two legs connected to apiston skirt at diametrically opposed points, a c'ollar enclosing the ends of said legs remote from their points of connection with the piston skirt and forming therewith an approximate semi-circle, and means tending to'separate the ends of the legs and to push them away from said collar. r Y

2. The combination of a piston having an.ex pansible skirt and an expander including two legs,

one end of each leg being pivotally' secured to the piston skirt at approximately diametrically opposed points, the otherfends of said legs being screw-threaded and adapted to be positioned within a collar, .and'nuts threadedbn said legs and adapted toforce the said legs outwardly against theinside of the piston skirt.-

'3'. Thecombina-tion of a piston having an expansible skirt anda piston-expander, said-ex,- pander including two spring legs, each of which is pivotally attached to said piston at diametrically opposed points, each of'which is screw- Also by.

threaded at the ends thereof remote from said pivotal connections, and each of which is forced apart at the screw-threaded ends thereof by nuts bearing against a collar.

4. The combination o1 a piston having an expansible skirt and a piston expander, said expander including two clips pivotally affixed to the piston skirt at diametrically opposed points and extendingvin a substantially semi-circular position and bearing against the insideof said piston skirt, said clips being forced apart at their free ends by nuts bearing ag'ainst'a collar surrounding said free ends, and screw-threaded to the said clips, said nuts bearing against the inner wall of said piston skirt. 7

5. The combination of a 'pistonhaving an expansibleskirt and a piston skirt expander, said expander including two clips pivoted to the inside of said piston and approximately fitting the internal periphery of saidpiston skirt, means for forcing thefree ends of said clipsapart, the said clips being of such length that they, may not'be.

pivotally swungout of the; piston skirt. p

6. The'combination of a piston havingan expansible skirt and a pistonskirt expander, said expander including spring clips, the combined length of which is greater than the length of onehalf of the inner periphery of the said skirt, said clipsbeing pivoted to the said skirt at diametricall -opposed points and secured together at their free ends by a collar and 'nuts screw-threaded to said clips, said nuts bearing against the inner side of said skirt. I

7; A piston skirt expander including two curved legs, oneend of. each of said legs pivoted to a piston skirt at approximately diametrically op posed points, the other ends of said legs extending Within a collar, and a nut'mounted on each of the second-mentioned leg ends and bearing against the said collar, the said legs and collar when in adjusted position being slightly greater than one-halfof the internal periphery of said piston skirt. 7 p

. JAMES B. EVANS

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