US1780183A - Piston - Google Patents

Description

P. M. FREER PISTON Nov. 4, 1930.

Filed June 1'7 1929 PPM/k5 ATTORN EYS Patented Nov. 4, 1930 PATENT OFFICE PHELPS M. FREEZE, OF DETROIT, MICHIGAN rIsroN Application filed June 17, 1929. Serial NO. 371,577.

The invention relates to pistons and refers more particularly to pistons having separately formed heads and skirts. One of the objects of the invention is to provide an improved construction of piston in which the head and skirt are automatically centered relative to each other. Another object is to provide an improved device for securing the head and skirt together. Further objects of the invention reside in the novel features of construction and combinations and arrangements of parts as will be more fully hereinafter set forth.

In the drawings: Figure 1 is an elevation, partly in section, of a piston embodying my invention, Figures 2 and'3 are cross sections respectively on lines 22 and 33 of Figure 1;

Figure t is an elevation of a portion of the securingdevice before assembly in the piston;

Figure 5 is a section through a piston having a modified device for securing the head and skirt together; Figure 6 is an elevation the modified securing device.

of a portion of In general, the piston comprises thehead 1 I and the skirt 2; The head is preferably formed of aluminum or an aluminum alloy and the skirt is preferably'formed of iron, the latter being adapted for engagement with the wall of the cylinder in which the piston operates and the former being preferably out of engagement with the wall of the cylinder. The head has the annular grooves 3 for receiving the piston rings and the pair oi diametrically opposite hubs i for receiving the wrist-pin which connects the connecting rod to the piston. The head has the annular skirt engaging shoulderno and the annular outwardly extending flange 6 providing the annular shoulder 7 opposed to the annular shoulder 5. The skirt surrounds the lower portion of the head including the hubs and the outwardlyextending annular jflange and is spaced laterally therefrom and one end of thisskirt is adapted to engage the annular shoulder 5.

. For the purpose of automatically center- 59 Y ing the-head and skirtrelat-ive to'each other 1 the annular shoulder 5 and the abutting end of the skirt are correspondingly bevelled.

For securing the head and skirt together I have provided as shown in Figures 1 to 4 inclusive, the resilient wire 8 which abuts the annular shoulder 7 and the inwardly extending flange 9 upon the end of the skirt abutting the annular shoulder 5. This resilient wire is loopedand curved to present an annulus and the loops are inclined so that the annulus is frusto-conical. The loops, in general, extend longitudinally of the piston but are inclined outwardly from their bases. Each loop has the legs 10 and 11 which are inclined peripherally relative to the base of the loops, the cam 12 connecting into the leg 10 and the extension 13 connecting into the cam 12 and the leg 11. The

, angle of inclination of each leg 11 is preferably less than the angle of inclination of each leg 10. The inwardly extending flange 9 is interrupted to provide recesses 14. for engaging the extensions 13 and intermediate solid portions 15 forming shoulders at one end for engaging the annular shoulder 5 and at the other end for engaging the cams 12.

The wire may be formed either continuous as by welding its ends or may be formed as shown with transverse terminals 15' extending within. transverse bores 16 in the head. securing the terminals in the bores, there is thescrew 17 threaded into the lower portion of the head 1 and having its head overlapping the base of thewire adjacent the terminals.

This screw also functions to hold the wire against the annular shoulder 7. In addition to this screw, therepreferably are one or more similar screws spaced angularly around the head and overlapping the base of the wire for holding the wire against the annular shoul der 7. r

To assemble the parts the wire is first placed around the lower portion of'the head l' andits terminals 15 are inserted in the bores 16 of the head placing the wire under tension after which the screws 17 are secured in place. The skirt 2 is then telescoped over the lower portion of the'head with the solid portions of the annular flange 9 upon this skirt in line with the extensions 13 of thewire and -forcing the same inwardly. After the skirt has been completely telescoped over the lower portion of the head so that it abuts the annular shoulder 5 upon the head, the skirt is then rotated to engage the shoulders formed by the solid portions of the annular flange 9 with the lowermost portions of the cams 12. Upon continued rotation of the skirt, these shoulders ride up on the c ms and the skirt is firmly engaged with the annular shoulder 5 of the head, at which time the shoulders i'ornr'edby the recesses i l of the annular flange 9 embrace the extensions 13 and hold the skirt from rotation in either direction. These shoulders are preferably bevelled to converge radially outward to take care of the variations in dimensions of the extensions and recesees and at the same time insure locking against rotation. I

When the loops of the wireare ini'iorn'ial position before assembly of the wire in the piston, as shown in Figure t, the lengths of the legs 10 and 11 of the wire, are so great that after assembly of the parts of the piston and when the skirt is being rotated and consequently cammed into place, the legs are periphally inclined to agreater extent and the wire is as a result placed under increased compression. V

IVith this construction, it will be seen that I have provided a construction of piston which has its head and skirt automatically centered, both by reason of the bevelled interengaging faces upon the head and skirt and the frusto-conical wire under compression both radially and axially oi the piston. It will also be seen that the wire may be mounted on the head under tension and that this wire is under compressionboth radially and axial- 1y when it locks the head and skirt together. Furthermore, the wire is of cheap construction,-and can be uniformly spring tempered owing to uniform cross section and no cross or short grain. It will additionally be seen that the wirepermits variation in expansion of the head-and skirt.

In the modification shown in Figs. 5 and (5 the skirt 18 has the inwardly extending annular flange 18 at its end abutting the annular shoulder 19 upon the head 20. This inwardly extending flange is bevelled at 21 to engage the upper ends of the loops of the resilient looped wire 22 which, as shown, is con tinuous and is preferably secured to the head by one or morescrews similar to those for securing the wire 8 to the head 1.

IVhat I claim as my invention is:

1. In a piston, the combination with head and skirt members, of means for securing said =j head. and skirt members together, including awire, said means-associated with said wire and one of said head and sk rt members for establishing a cam engagement therebetween upon relative rotation of said last mentionedf member. and said Vii-6..

2. In a piston, the combination with head and skirt members, of means for securing said head and skirt members together, including a wire secured to one of said head and skirt members and means associated with said wire and the other of said head and skirt members for establishing a cam engagement therebetweei'i upon relative rotation of said last mentioned member and wire.

3. In a piston, the combination with head and skirt members-of a wire member secured to one of said head and skirt members and means associated with said wire member and the other of said head and skirt members for establishing a we'dgin action therebetween to secure said head and skirt members together.

4. In a piston, the combination with head and skirt members, of means for securing said head and skirt members together including a wire member having. a cam portion -en gaging one of said head and skirt members upon relative rotation of said last mentioned member and wire member, and means for holding said wire member in cam engagement with said last mentioned member.

5. In a piston, the combination with head and skirt members, of a wire ring secured to one of said members and having a cam portion engaging with the other upon relative rotation of said last mentioned member" and wire ring and means for holding said wire ring in cam engagement with said last mentioned member. 7

6. In a piston, the combination with head and skirt members, of means for securing said head and skirt members together including a wire member having a cam portion engaging with one of said head and skirt member's upon relative rotation of said lastmentioned member and wire member, said last mentioned member and wire member-having cooperating interlocking portions for holding said wire member in cam engagement with said last mentioned member.

7 In a piston, the combination with head and skirt members, of means for securing said head and skirt members together, including a resilient looped wire members engaging one of said head and skirt members and means associated with said wire member and the other of said head and skirt members for establishing a wedging action therebetween.

8. In a piston, the combination with a head member having a shoulder and a skirt member abutting said shoulder and having an inwardly extending'flange, of means for securing said head member and skirt member to each other including a resilient looped wire member abutting said head member, and the inwardly extending flange of said skirt: m m her, said inwardly extending flangeand-a loop of said wire Inemberhaving cooperatifig interlocking shoulders for holding said skirt member from rotation relative to said Wire member. 7

9. In a piston, the combmatlon with a head member having a shoulder and an out- Wardly extending flange, and a skirt member having an inwardly extending flange abutting said shoulder, of means for securing said head member and skirt member to each other including a resilient looped wire member engaging said outwardly extending flange and having its loops provided with cam portions for engaging said inwardly extending flange and with extensions beyond said cam portions, said inwardly extending flange being interrupted to provide recesses for receiving said extensions.

In testimony whereof I aflix my signature.

' PHELPS M. FREER.

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