US2167287A

US2167287A - Piston skirt expander

Info

Publication number: US2167287A
Application number: US710658A
Authority: US
Inventors: Leon A Witter
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-02-10
Filing date: 1934-02-10
Publication date: 1939-07-25
Anticipated expiration: 1956-07-25

Description

Jul 25, 1939.

L. A. WITTER PISTONSKIRT EXPANDER Filed Feb. 10, 1934 B /Z r 4%?" attorneys Patented July 25, 1939 UNITED; STATES "PATENT OFFICE PISTON SKIRT EXPANDER Leon A. Witter, Parma, Ohio Application February 10, 1934, Serial No. 710,658

13 Claims.

, This invention relates toexpandirig devices and more particularly to an improved device for expanding the skirt of a split skirt piston of the type commonly used in the internal combustion;

5 engines of automotive vehicles.

Aluminum alloy pistons having split skirts are in very extensive use. In a common form of-this v type of piston the skirt is secured to the head por- 20 uneven wearing of the skirt which results in an uneven bearing against the walls of the cylinder. When this occurs piston slap or' knocking re- Y suits, at least when the engine is cold. In order to overcome this diflicultypistons are now manu- 25 factured, the skirts of which are originally ground inan oval or elliptical form so that when they expand upon being heated to operating temperature they become round and thus properly fit the walls of the cylinder.

Anumber of devices have'been proposed, and

are inextensiVe use, for expanding the skirt of a piston having a slotted skirt to increase the diameter-of the skirt and make it fit the cylinder wallsafter it has been worn to such an extent .35 that knocking occurs. The devices; of this type bodiment of my invention.

with'which I am familiar are "in the nature of expanding rings which fit inside the walls of the piston skirt and may be expanded by suitable means to cause an increase inthe diameter of the 40 skirt.

It is among the objects of my invention to provide means for expanding :the skirt of a slotted skirt piston wherebya worn piston may be made to properly fit within the cylinder; Other objects '45 of rnyinvention-are: the, provision of a piston skir't expanding device which may be quickiyand easily inserted in apistonand which may be set to give any desired degree-of expansion of the piston; the .provisionof apis'ton skirtexpanding 50 device which is of lightweight and small size and which does not 'interfere'with the normal opera-- tion of the piston or its associated parts; the provision of a piston skirt expanding device which isadaptedto expand a worn piston and give the 55 skirt of the piston an ellipticalshape whereby the desired operating characteristics are obtained; the provision of a piston skirt expanding device which is adapted to expand the skirt of a piston without destroying the inherent resiliency of the slotted skirt; the provision of a piston skirt expanding device which is particularly susceptible to economical manufacture, which may be readily installed and which, once installed, will notbecome dislodged while the piston is in use.

The above and-other objects of my invention will. appear from the following description of several embodiments thereof, reference being had to, the accompanying drawing, in which Figure 1 is an enlarged perspective view of my piston skirt expanding device showing the parts; in assembled position.

' Figure 2 is a cross section taken on line 2-2 of Figure 5 and also showing portions of the wall of the piston skirt to which the expanding device is attached- Y Figure 3 is a longitudinal cross sectional view taken on line 3-3 of Figure 1 and illustrating the expanding device of Figure 1 with the parts in the positions they assume when the device is installed in a piston.

Figure 4 is a detached viewer the flexible slotted tapered sleevepurtion of my expander.

Figure 5 is a side elevation of a'slottedskirtpistan with one of my expanding devices installed therein. Figure 6 is a fragmentary view illustrating a portion of the skirt of a piston with my expand- ,ing device installed.

Figure '7 is a cross se tional view: similar to Figure .3 but illustrating aslightly modified-em: '36 a,

Figure 8 is a detached perspective view of the locking washer illustrated in Figurefl.

Figure 9 is a perspective view, approximately fullscale, of a modified form of my piston ex- 40 pander. v Y FigurelO is a :cross sectional view generally 7 similar to Figure 2 but illustrating a different form ofthe sleeve member.

Referring now to Figure 1, my improved ex- I panding device comprises a tapered slotted sleeve i preferably made of spring sheet steel orthe like and having its edges 3 and '4 adjacent. the longitudinal slot vZturned back-to form hook shaped lipsor flanges which are adapted to engage the and length of the plug are preferably such that the large end of the plug projects out beyond the large end of the sleeve I when the inner surface of the sleeve and the outer surface of the plug are in contact. The screw 1 is adapted to have threaded engagement in the hole 6 of the plug 5 and is provided with an enlarged portion,

preferably a slotted head 8, to facilitate adjust-' ment of the expander and form a shoulder which will coact with the sleeve I to draw the plug 5 into the sleeve. posed between the underside of the head 8 of the screw and the small end of the tapered sleeve I and serves to assist in locking the screw in ad-- justed position.

Before installing my expanding device in a piston the edges of the slot in the piston skirt are chamfered as is clearly seen in Figure 2. Any suitable tool may be used for this purpose but, as such tool does not form part of this invention, it need not'be described here. Next the expanding device, with the parts assembled as shown in Figure 1, is slipped upwardly into the position shown in Figure 5 with the large end of the plug 5 toward the head of the piston and with the hook shaped

lips

3 and 4 engaging the edges of the slot in the piston. Preferably the device is positioned with the center'of the tapered sleeve lying substantially on a plane passing through the centers of the piston pin bearings. Next, the screw I is rotated to draw the tapered plug 5 down into the sleeve l. that, as the plug 5 enters the sleeve I it will force the lips 3 and A apart increasing the width of the slot 2 and forcing apart the edges of the slot in the piston. As the portions of the piston skirt adjacent the slot are-anchored to the webs W (Figure 2) this expansion of the slot will cause the portions A and B of the piston (see Figure 5) to swing outwardly about the points C and D (Figure 2) thus increasing the transverse dimension of the piston skirt and forming an oval shaped piston which possesses all of the advantages of a piston having a skirt originally ground to such form.

As is seen in Figure 2 I preferably shape the tapered sleeve I so that the portions of the sleeve immediately adjacent the

lips

3 and 4 and the slot 2 do not contact with the surface of the .plug 5. Thus, when the expanding device is in position and the piston skirt walls have been expanded the function of the slot in the skirt is not. destroyed as the walls of the skirt are. still permitted a certain flexibility of movement due to the fact that the sleeve I does not engage the plug 5 throughout its entire circumference.

5 In Figure 10, which is a cross sectional view similar to Figure 2, but illustrating a slightly different embodiment of my expander, the sleeve member is of an oval cross section and engages the plug 5, which is preferably of circular cross section, at the sides I1 and I8 thereof but is spaced from the plug member on what we may call the front l9 and the back portion 20 thereof. This arrangement providesfor asomewhat more flexible'movement than does the arrangement of Figure 2 but it will be understood that the function of spacing the walls of 'the sleeve to permit the slot in the skirt of the piston to perform its intended function after my expander device has been installed.

. In Figure 7 I have illustrated a modified form of my piston expander in which the underside of A lock washer 9 may be inter- It will be seen.

the sleeve I and prevents relative rotation of the washer and sleeve. vThiswasher and serrated head surface gives a ratchet action upon rotation of the screw to expand the piston skirt and provides an indication of the degree of expansion given to the piston skirt as well as preventing the loosening of the screw. A pin I3 is illustrated in Figure 7, this. pin extending out from the body of the plug 5 into the slot 2 of the sleeve I; This pin does not, however, extend beyond the edges of the

lips

3 and 4 and serves merely to prevent relative rotation of the plug 5 and sleeve I thus insuring that the plug will be drawn into the sleeve upon rotation of the screw I in the proper direction.

3 and 4 at the large end of the sleeve I are preferably rounded off to prevent the hardened spring steel of the sleeve from digging into the relatively soft metal of the piston'and to facilitate the insertion of the device in the slot inthe piston skirt. The ends of the flanges or lips 3 and I at the small end of the sleeve I, however, have sharp edges which are adapted to dig into the soft metal of the edges of the slot in the piston and effectively prevent accidental removal'of the device. I I

In Figure 9 I have illustrated, in approximately full size, a modified form of my expanding device in which the plug member 5 is provided with a transversely extending lug or flange It at its large end. This flange is adapted to engage the inner walls of the piston skirt when the device is installed and prevents the plug 5 from rotating within the sleeve I. When this flange I4 is used it will not be necessary to provide a pin l3 as illustrated in Figure 4.

My complete expanding device weighs less than one-half ounce and I have found that it does not materally change the balance of the piston or in any way affect the operation of the vehicle engine except to improve the fit of the piston in the cylinder. A single size of expanding device may be used with a large range of sizes of pistons and my expanding device can be used to expand the pistons any amount within the usual practical limits. 7

Although I have described in considerable detail the illustrated embodiments of my invention it will be seen by those skilled in the art that variations and modifications may be made in the specific 'form of my piston expander without departing from the spirit of my invention. I do not therefore wish to be limited to thespecific form described and illustrated, but claim as my invention all embodiments thereof coming within the scope of the appended claims.

I claim:

1. A piston skirt expander including a tapered sleeve'member having a slot extending lengthwise thereof, said sleeve having lip portions adjacent saidslot adapted to engage the edges of a slot in the skirt of a piston, a tapered plug fitting within said sleeve and means for drawing said plug into said sleeve to vary the width of said slot in said sleeve.

2, In a piston skirt expander, a tapered, resilient sleeve slotted longitudinally and having piston engaging lips adjacent the slot therein, a

.ai m v.

piston engaging tapered plug member disposed within said sleeve and means for moving said plug longitudinally of said sleeve. I

. 3. In a piston skirt expander, a tapered sleeve slotted longitudinally having piston engaging lips adjacent the slot therein and adjustable means acting longitudinally of the sleeve and engaging the same for varying the distance between said lips.

4. In combination with a pistonhaving a slotted skirt, a skirt expander disposed in theslot and adapted to vary the width thereof, said expander comprising aslotted sleeve member having lips removably engaging the edges of the slot in the piston and means for expanding the slot in said sleeve whereby the width of the slot in the piston will be increased.

5. In a piston skirt expander, a'tapered, resilient sleeve slotted longitudinally and having piston engaging lips adjacent the slot therein, a tapered plug extending into said sleeve, said pl having a threaded aperture extending thereinto, a screw having threaded engagement with siiid' plug in said aperture and .extending out of. the small endof said sleeve, said screw having an enlarged portion on the end which extends out of the sleeve, said enlarged portion being adapted to engage the end of said sleeve whereby rotation of said screw in one direction will draw said plug into said sleeve and expand the slot therein.

6. In a piston skirt expander, a tapered, resilient sleeve slotted longitudinally and having piston engaging lips adjacent the slot therein, a tapered plugextending into said sleeve, said plug having a threaded aperture extending thereinto, a screw having threaded engagement with said a plug in said aperture and extending out of the small end of said sleeve, said screw having an 'enlarged portion on the end which extends out I tion of said screwjn one direction will draw said of the sleeve, said enlarged portion being adapted tocengage the end of said sleeve whereby rotaplug into said sleeve and expand theslot therein, and means-for locking said sleeve and plug against relative rotary movement.

7. In a piston skirt expander, a tapered, re silient sleeve slotted longitudinallyand' having piston engaging lips adjacent the slot therein, a

1 plug' having ,a laterally extending 'lugon its large end [adapted to engage the wall of the piston skirt whereby relative rotary movement of' the plug and sleeve is prevented.

8,111 a piston expander, a tapered. resilient sleeve slotted longitudinally and having A a lips adjacent the slot therein, a

tapered plug extending into said sleeve, said plug having a threaded aperture extending thereinto,

- a screw having threaded engagement with said plug in said aperture and extending out-of thesmall end of saidsleeve, said screw having an enlarged portion on the end which extends out of the sleeve, said enlarged end being adapted to engage the end of said sleeve whereby rotation of said screw in one direction will draw said plug into said sleeve and expand the slot therein, and a pin extending from the surface of said plug into the slot in said sleeve whereby relative rotary movement of said sleeve and plug will be prevented. i

9. Ina piston skirt expa'nder of the'type described, a resilient, slotted, tapered sleeve, a tapered plug disposed in said sleeve, saidplug being formed to engage the inner suface of said sleeve except adjacent the slot in said sleeve and means for moving said'plug into said sleeve. to expand said slot.

10. -In a piston skirt expander of the type described, a resilient, slotted, tapered, sleeve having lips adjacent the slot thereof adapted to en-- gage the edges of the slot in the skirt of a piston, said lips having their ends adjacent the large end of the sleeve rounded off to facilitate insertion of the expander lips into the piston skirt slot and having their opposite ends relatively sharp whereby to dig into the metal of the edges of the piston skirt slot and resist removal'of said sleeve from said slot, and means coacting with said tapered sleeve'for varying the distance between said lips.

.11. In an expanding device, a resilient slotted;

tapered sleeve, a tapered plug disposed in said sleeve, said plug being shaped to engage the inner surface of said sleeve on areas extending lengthwise of the sleeve on the sides thereof and to be spaced from the sleeve adjacent the slot therein and adjacent the portion of the sleeve opposite from said slot, and means for moving' said plug into said sleeve to expand said slot.

12. In an expanding device, a resilient, slotted, tapered sleeve, a plug disposed in said sleeve, said plug engaging the walls of said sleeve .on portions thereof and being spaced from the walls of thesleeve at other portions thereof whereby the ed s of hue slot insaid sleeve may be moved toward each other whensaid plug is in position in the sleeve.

1a...1nan expanding device, r resilient, slotted, tapered sleeve, a plug disposed in said sleeve,

said plug engaging the walls of said sleeve on portions thereof and being spaced from .the walls of the sleeve at other portions thereof whereby the edges ofthe'slot in said sleeve may be moved.

toward each other when said plug is in position in the sleeve, and'ineans for moving said plug 7 into said tapered sleeve to vary the wi'dth of the slot in said sleeve.