US2223787A

US2223787A - Piston expander

Info

Publication number: US2223787A
Application number: US312764A
Authority: US
Inventors: Walter C Knoebel
Original assignee: SKF Automotive Products Inc
Current assignee: SKF Automotive Products Inc
Priority date: 1940-01-06
Filing date: 1940-01-06
Publication date: 1940-12-03
Anticipated expiration: 1957-12-03

Description

Dec. 3, l1940. W C KNOEBEL 2,223,787

PI STON EXPANDER Filed Jan. 6, 1940 FIG l 3 Q W I 7/ NLS I N vE/vroR WALTER C. KNOEBEL PatentedV Dec. 3, 1940 PISTON EXPANDER Walter C. Knoebel, Kirkwood, Mo., assignor to McQuay-Norris Manufacturing Company, St. Louis, Mo., a. corporation of Delaware Application January 6, 1940, Serial No. 312,764

8 Claims.

My invention relates to piston expanders and more particularly to piston expanders for use in split pistons of internal combustion engines or vother devices wherein it is desirable to have the 5 expander adjustable so that the expansive force created thereby to open up the skirt and increase the effective diameter of the piston may be controlled definitely.

Heretofore, such expanders have been made in l various shapes and sizes and different expedients have been used to provide adjustability. The objects of my invention are to provide an expander of the type described above which will expand effectively the skirt of a worn piston and ll assure efficient operation of an engine in which the piston is used; to provide an expander arranged whereby the expansive force exerted thereby can be regulated and controlled; and to provide an expander which is simple in design,

20 heap in manufacture and eflicacious in operaion.

In the accompanying drawing wherein similar characters arer used to.l designate similar parts, I have shown one embodiment of my invention.

85 In the drawing, Fig. 1 is a longitudinal section through a piston including my device; Fig. 2 is `a bottom View of the assembled piston and expander; Fig. 3 is a section along the line 3 3 in Fig. 1; Fig. 4 is Va transverse section along 80 the line 4 4 in Fig. 1; Fig. 5 shows the expander removed from the piston; and Fig. 6 is a section along andis indicated by the line 6-6 in Fig. 5.

Referring to the gures, the piston shown as including my invention has a head A including a 35 ring belt B provided with a plurality of ring receiving'grooves C and a skirt D separated from the head throughout themajor portion of its periphery bycircumferentially extending slots E. In order to give resiliency to the skirt B,

0 preferably, it is split longitudinally as at the slot F. 'I'he piston also includes the usual bosses G to receive a wrist pin H upon which is mounted the'upperend of the connecting rod J.

The expandershown and described herein as embodying my invention includes a plurality oi spring members K formed of spring Wire in this embodiment. These spring members are arranged inA pairs with the members in each pair crossing-one anotherv and extending across the BQ hollow interior of the piston, as shown in Fig. 1. The upper ends of the spring members K are anchored to the piston, preferably in the head thereof, and the lower or free ends of the members K are adapted to engage and exert an exi# pansive force outwardly against the piston skirt when adjusted, as explained below. In this embodiment, parts L arranged to engage and bear against the inner surface of the piston skirt at substantially diametrically opposed points are fixed to the lower or free ends of the members K in adjacent pairs.

Extending through each skirt engaging part L is a rod M which is threaded at its lower end to receive an adjusting nut N and which has a yoke P formed on its upper end. The yoke P may be integral with the rod M or may be secured thereto by any suitable expedient. In this embodiment each yoke P is provided with holes Q to receive the anchored or iixed ends of the spring members K, for the purposes to be outlined below, and, preferably, the spring members K have iiattened portions R or are otherwise arranged whereby the passage of the ends of the spring members through the yokes will be limited and these ends prevented from extending more than a short distance beyond the outer side of a yoke. Preferably, the yokes P are formed arcuate in shape to t the rounded inner side of the piston wall when the expander is mounted in place as will be hereinafter fully explained.

The ends of the spring members K may be secured to the skirt engaging parts L in any way but in this embodiment and as shown in Fig. 6 the free ends of the members K are reduced asv at S to form a shoulder removed from the end thereof and the parts L are drilled to receive the reduced ends beyond the shoulder. After the expander is assembled as shown in Fig. the outer ends of these reduced portions are expanded as by hammering and each part L will be carried by the free ends of adjacent spring members K.

'Ihe manner of installation and operation of thisl form of expander embodying my invention is as follows: The expander is assembled into the form shown in Fig. 5 and the nuts N are turned into a position at the end of the rods M. The upper ends of the spring members K are inserted in and through the holes Q in the yoke P and the expander is then slid upwardly into the hollow interior of the piston from the bottom thereof. Of course, the connecting rod and piston pin must be removed before the expander is inserted in place in the piston and preferably the expander is placed in the piston so that the parts L engage the skirt at points removed approximately ninety (90) degrees from the pin bosses. As explained above, preferably, the expander has the upper ends of the spring members anchored in the piston head and to accomplish thi-s two pairs of holes T are drilled in the bottom of a piston ring groove C with the holes in one pair being opposed to the holes in the other pair, as shown in Fig. 4. The holes in each pair are positioned to register with the ends of the spring members K projecting outwardly from the yokes P and as the expander is slid upwardly in the piston these ends of the spring members will enter the holes T and each yoke P will bear against the inner side of the wall of the piston head A. After the expander is in place in the piston the nuts N are turned by a wrench or other tool to move the skirt engaging parts and the free ends of the spring members K upwardly and closer to the anchored ends of the spring members. Obviously, as such upward movement is continued the free ends of the spring members K will create an increasingly greater expansive force outwardly and the expansive force so created will be exerted on the piston skirt through the parts L.

I have found that to obtain best results the piston and its expander in free or unadjusted condition should be placed in its cylinder before adjustment of the expander is made. When this is done, the nuts N can be turned and manipulated to expand the skirt to the proper degree and effect a good and proper iit between the piston and the cylinder wall with minimum effort.

If the spring members andother parts of the expander are formed as in this embodiment the members K in each pair will cross ata point above the pin bosses and above the'wrist pin H and if for any reason the expander becomes dislodged accidentally it will be prevented from dropping into'the crank case of the engine.

As stated above I have shown herein one embodiment only of my invention but it should be understood that the arrangement, position, size, and shape of the various parts of the expander may be changed within wide limits in adapting my invention to expanders of various'types. For instance, spring metal may be substituted for the spring wire used to form the membersK in the present embodiment. This and other changes may be made without deviating from the spirit of my invention as included in the appended claims.

What I `claim as new and desire to secure by Letters Patent is: c

1. A piston expander comprising a pair of spring members extending across the hollow interior of the piston and crossing eachv other,` one end of each of said members having a part arranged to engage the inner surface of said skirt and means joining adjacent ends of said members for movingl the adjacent ends of said members relative to each other whereby the expansive force created by said spring members and exerted by said engaging parts lagainst said skirt can be adjusted.

2. A piston expander comprising a pair of spring members extendin-g across the hollow interior of the piston and crossing each other, Ione end of veach `of said members having a part arranged to engage the inner surface of said skirt and means joining adjacent ends of said members for moving the adjacent ends of said members away from or toward each other whereby the expansive force created by said spring members and exerted by said engaging parts against said skirt can be adjusted and said means being arranged to maintain said members in adjusted position.

3. A piston expander comprising a pair of spring members extending across the hollow interior of the piston and crossing each other, each of said members having one end thereof anchored in the piston wall and the free end thereof carrying a part arranged to engage the inner surface of the piston skirt, and means joining adjacent ends of said members for moving the free end of one member relative to the anchored end of the other member whereby the expansive force created by said spring members and exerted by said parts against said skirt may be adjusted.

-4. A piston expander comprising a pair of spring members extending across the hollow interior of the piston and crossing each other, each of said members having one end thereof anchored in the piston wall and the free end thereof carrying a part arranged to engage the inner surface of the piston skirt, means joining adjacent ends of said members for moving the free end of one member away from or toward the anchored end of the other member whereby therelative force created by said spring members and exerted by said parts against said'skirt can be adjusted, and said means being arranged to maintain the ends of said members in adjusted position.

5. A piston expander comprising a pair of spring members anchored at opposed points in the wall of Va piston head and extending across thel hollow interior of said piston, one end of each of said members being free and carrying a part arranged to engage'the inner surface of the piston skirt, means joining adjacent ends of said members for moving the part carried by the free end of one member away from or toward the anchored end of the other member whereby the expansive force created by said spring members and exerted by said parts against said skirt can be adjusted.

6. A piston expander comp-rising a pair of spring membersA with an end of each member projecting into a suitable aperture formed in the piston vwall whereby said ends will be xed, said members 'extending across the hollow interior of .said piston and crossing each other, the free end of each of said members being arranged to engage the inner surface of the piston skirt, means joining adjacent ends of said members for moving the free end of one member toward the fixed end of the other member whereby the expansive force created by said spring members and exerted by said parts against said skirt may be adjusted.

.'7.A piston expander comprising a pair of? spring members with an end of each member projecting intoa suitable aperture formed in the piston wall whereby said ends will be fixed, said members extending across the hollow interior of said piston and crossing each other, the free end of each of said members carrying a part arranged toengage the inner surface of the piston skirt, a rod secured to the fixed end of each of said spring g members and extending through said part carried by said free end and means for moving said part along said rod wherebyIsaid free end of one of said spring members can be moved away from or toward the xed end of the other member and the expansive force created by said spring members and exerted by said partsagainst said skirt can be adjusted.

8. A piston expander comprising a pair of spring members with an end of each member projecting into a suitable aperture formed in the piston wall whereby said ends will be xed, said members extending in opposite directions across the hollow interior of said piston and crossing each other, the free end of each of said members carrying a part arranged to engage the inner surface of the piston skirt, a rod secured to the fixed end of each of said spring members and extending through said part carried by said free end and means for moving said part along said rod whereby said free end of one of said spring members can be moved away from or toward the fixed end of the other member and the expansive foree created by said spring members and exerted by said parts against said skirt can be adjusted, and means arranged to maintain said parts in adjusted position on said rods.

WALTER C. KNOEBEL.