US733665A - Packing-ring for pistons. - Google Patents

Description

No. 733,665. 'PATENTED JULY 14, 1903.

H. LEMP.

PACKING RING FOR PISTONS.

APPLICATION IILED NOV. 21, 1901.

witnesses: Irv oenbo Hermann Lem la mgg, p

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Urvrrsn STATES Patented July 14, 19031 PATENT OFFICE.-

HERMANN LEMP, OF LYNN, MASSACHUSETTS, ASSIGNOR TO ELIHU THOMSON, OF. SWAMPSCOTT, MASSACHUSETTS.

PACKING-RING FOR PISTONS.

SPECIFICATION forming part of Letters Patent No. 733,665, dated July 14, 1903.

Application filed November 21, 1901. Serial No. 83,183. (No model.)

To (0M whom it may concern:

Be it known that I, HERMANN LEMP, a citizen of the United States, residing at Lynn, in the county of Essex, State of Massachusetts, have invented certain newand useful Improvements in Packing-Rings for Pistons, of which the following is a specification.

To fit piston-rings as ordinarily constructed requires a skilled workman, and the results obtained are not always satisfactory unless the man has had particular training in this branch of work. The difficulty is to make the ring in such manner that it will make a close fit with the piston-body and at the same time have a'perfectly-true periphery for engagement with the inner wall or surface of the cylinder. The rings are springy, and thereforea joint has to be provided, and particular difficulty is experienced in making this joint so that no leak will take place at that point when the piston is operatively mounted in a cylinder. A number of rings are usually employed, and great difficulty is experienced in making the several joints and assembling the rings in such manner that no leak will take place when the piston is in operation. Good practice dictates that the rings shall be prevented from rotating by the use of akey, thus increasing the cost of manufacture. When the pistons are large, the difficulty of fitting the rings is less than where they are small, for obvious reasons.

I have discovered that by using laminated punchings the carefully and accurately fitted joints may be dispensed with, and, furthermore, that the machine-work on the ringssuch as turning, for example-can be obviated.

In the accompanying drawings, which illustrate an embodiment of my invention, Figure 1 is a sectional view of an engine-cylinder, showing the piston in elevation. Fig. 2 is a vertical section of the. piston. Fig. 3 is a perspective view of one of the followerrings. Fig. 4 is a perspective view of one of the packing-rings. Fig. 5 is a detail view, in horizontal section, of the piston and rings. Fig. 6 is a similar view of a slight modification. Fig. 7 is a detail View of an ordinary piston-ring in the process of construction,

and Fig. 8 is a detail view showing the lastmentioned ring as it appears when in use.

Various kinds of joints for piston-rings have been devised. The one shown in Figs. 7 and 8 is a common one and is used to illustrate the character of work necessary in properly fitting a ring.

1 represents an ordinary cast-iron ring having a finished periphery and bore, also finished sides. The diameter of the ring as originally formed is somewhat larger than that of the cylinder-bore. The sides of the ring are slotted radially at 2 and 3, the lefthand side of the slot 2 coinciding with the right-hand side of the slot 3. Completing the slots also splits the ring, and the surfaces 4. and 5 will engage with each other when the ring is compressed and ready for use, as in Fig. 8. Steam or gas, as the case may be, can enter the slots 2 and 3, so that the real restriction to the passage thereof is found in the joint formed between the surfaces 4 and 5. This joint is shunted by a second jointi. e., the one between the ring and the piston-bodyso that if the ring does not make a very tight fit the steam or gas will pass from the slot 2 through the said space or joint to the slot 3.

My improved packing is made of laminated I punchings, and I have found low-grade machine-steel one thirty-second of an inch thick to be satisfactory for the follower,while for the piston-ring untempered tool-steel is used, although my invention is not to be construed as being limited to this precise kind and thickness of stock. Two kinds of rings 6 and7 are employed, the former being termed a follower and the latter a packing ring. The inside diameter of the follower-ring is such that the ring will make a tight fit with the body 8 of the piston, so that no opportunity is afforded for the steam or gas to leak at this point. I have shown a trunk-piston; but the invention can be used in connection with pistons of any suitable construction. The outside diameter of the follower-ring is slightly less than the internal diameter of the cylinder. The ring is made with an ordinary punch and die, and no finishing of any character is required. Each packing-ring is punched a trifle larger than the bore of the cylinder, in the particular case illustrated one sixtyfourth of an inch larger. The opening in the center of the ring is somewhat greater than the diameter of the piston-body. In the present instance a clearance of one thirty-second of an inch is provided. The ring is slotted at 9, the sides of the slot being perpendicular to the plane of the ring. No attempt is made to finish the ring after punching, either by turning the periphery or bore or in any way cutting the slot 9. Thus it will be seen that by using a good punch and die both of the rings may be applied to the piston without extra machine-work.

The piston-body Sis provided with a shoulder at its lower end, and surrounding the body and resting on the shoulder are the rings 6 and 7. In assembling I prefer to alternate the rings, so that a split or packing ring is located between two follower-rings. The slots 9 in the packing-rings should be arranged to break joint. In Fig. l the joints are shown as staggered on the front of the piston-body, this being done for the purpose of illustration; but in practice the joints are preferably located at various points around the piston. The rings are held in place against the shoulder by the end plate 10, the latter being secured by the bolt 11. The end plate is shouldered on the under side, which shoulder fits into a corresponding depression in the pistonbody. The piston is connected to the crank by the rod 12 in the ordinary manner.

Referring to Fig. 5, the rings are shown on an enlarged scale and the space between the packing-rings '7 and the piston-body 8 is shown on an exaggerated scale for the purpose of illustration.

In Fig. 6 the follower-ring 6 is split, as well as the packing-ring 7. This enables me to put the rings on a piston where the body has not been accurately turned.

The pistons illustrated are of small size, and being of the trunk variety, where no guides are used for the piston or connecting rod, the rings cover the entire length; but for larger pistons or pistons having rods and guides the rings may cover only a portion of the body.

The opportunity for steam or gas to leak from one end of the piston. to the other is reduced to a minimum by reason of the close association of the packing and follower rings when clamped in place. The only passages open to the steam or gas are the very small spaces 9, further communication being prevented by the follower-rings, which bear on the flat sides of the packing-rings. Again,

the friction contact or fit between the follower-rings and the piston-body will prevent steam or gas from passing at that point. When split follower-rings are used, the spaces formed therein should of course be staggered with respect to those of the adjacent packingrings. In actual. service it has been found that the rings wear to a good bearing-surface and that the interior of the cylinder becomes smooth and polished. It has also been found that the leaking around the piston has been materially reduced.

In an engine provided with three pistons the cost of nine turned rings, three for each piston, was one dollar and sixty cents, whereas with my improved rings the cost for three pistons was only eight cents.

The advantage of my improved structure is twofold-first, reduced first cost and consequent cheapness in replacing, and, second, greater efficiency on account of the reduction in steam or gas leakage.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. In a piston-packing, the combination of a cylindrical body having a seat, a plurality of split non-overlapping laminated springmetal packing-rings which surround the body and are separated therefrom by a space which permits the rings to expand and contract slightly, a plurality of laminated-metal follower-rings which also surround the body and are in frictional engagement therewith, and a head for securing the rings in place.

2. In combination, a piston-body, a plurality of split packing-rings punched out of laminae and making a loose fit with the pistonbody, the joints in said rings being staggered, follower-rings also punched out of lamina; and arranged to separate the adjacent packin g-rin gs, the said follower-rings being closely fitted to the piston-body, and a means common to the packing and follower rings for securing them in place.

3. In combination, a piston-body, a plurality of split packing-rings made of laminze and arranged to loosely surround the piston-body, a plurality of split follower-rings also made of laminae and arranged to make a tight fit with the piston-body, the joints in the packing and follower rings being staggered, and means for firmly clamping the sides of one ring against the sides of adjacent rings to prevent leakage.

In witness whereof I have hereunto set my hand this 18th day of November, 1901.

HERMANN LEMP.

WVitnesses:

DUGALD MoK. MCKILLOP, JOHN A. McMANUs.

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