US2819917A - Hydraulic packings - Google Patents

Description

Jan. 14, 1958 T. F. WATSON ETAL 2,819,917

' HYDRAULIC PACKINGS Filed Nov. 14, 1955 2 Sheets-Sheet 1 I ATTORNEY Jan. 14, 1958 T. F. WATSON ET AL. 2,819,917

HYDRAULIC PACKINGS 2 Sheets-Sheet 2 Filed Nov. 14, 1955 A TTORNE) United States Fatent HYDRAULIC .PACKINGS Thomas Frank Watson, William Thomas- Tank,-and'Ccil Henry Bonsey, Waking, England assignors to James Walker and Company Limited, Surrey, England, a corporation ofGreatBritain Application November 14, 1955, Serial No. 546,614

Claims priority, application Great Britain October 25, 1955 4 Claims. (Cl. 286-26) This invention-relates to hydraulic packings for use in' making fluid tight joints in hydraulic machinery, for example; around the ram or piston of a hydraulic press,

of the kind which consists in a header ring adapted to maintain the lips of a U-shape or other suitable sealing member incontact with the surfaces to be sealed, said header ring being adapted so that in use it is spring loaded by means of a number of coil springs which are maintained permanently in position on the header ring bymeans of headed pins having shanks which are slidable in holes in the header ringand which form mountings for the springs which at one end bear against the undersides of the heads of the pins and at the opposite ends against the bottoms of recesses or drillings in the header ring.

Packings of the above kind as previously proposed.

comprised pins having elongated shanks that extended beyond the underside of theheader ring and into the gap between the lips of the sealing member when the springs are compressed said pins being prevented from becoming sufiiciently wide and deep as to be able to receive the,

peened over ends of the shanks of the'spring retaining pins when fully loaded. A further disadvantage resides in the fact that the peeningover of the shanks of the pins had to be effected with the pins in position in the header ring and with each spring compressed to cause the shanks to project to their full extent beyond the underside of the header ring. Unless exceptional care was taken the hammering necessary to effect peening caused the unsupported part of the shank of each pin protruding beyond the header ring to bend and require either its replacement'or correction.

The object of the present invention is to avoid the above disadvantages and this is effected by a construction which enables each pin and its spring to be assembled as a unit and for each said unit to be fitted into a recess in the header ring and preferably so that when thus fitted the units are incapable of falling out whilst the header ring is being handled.

Broadly the present invention consists of a spring unit to form with a header ring a spring loaded packing said unit comprising a headed pin, a coil spring mounted on the shank of the pin and an annular spring pad on the outer end of the shank of the pin, the central hole in said spring pad permitting said shank to slide through it and said spring pad forming a seating for the spring said spring pad and the spring being maintained in position on the shank of the pin to form a unitary structure by an enlargement on the outer end of the said shank which is formed after the spring and its pad have been assembled on the shank of the pin.

In a spring unit as above according to a preferred embodiment of the present invention the spring is held under slight compression between the head of the pin-at one end and the spring pad at the opposite end and-said spring pad-is in-the form of a dished annular washer-having a peripheral diameter slightly greater than the internal diametcr of the recesses in the header ring-whereby on fitting the spring units into the header ring-eachsaid unit requires to be pressed firmly down to the bottomofeach By this means the tendency of each spring pad to expand will prevent the units from falling out when-therecess.

packing is being handled.

In this preferred embodiment the enlargement on the inner end of the pins shank will just enter the concentrichole which is drilled through the headerring from'the bottom of each recess and will be free to'slide downand' up in the hole as the pin is depressed and released. The

shanks of the pins may thus be of such a length thateven when fully depressed their outer ends need never-protrudebeyond the depth of the header ring.

The enlargement at the outer end of each pin shank is made after the spring pad is pushed-into position over'the' freeend of the shank and this may be effectedeither-by peening or by pinching in the sides of the shank on opposite sides to cause the metal to displace laterally.

Where the material composing the header ring issufii ciently hard there is no need to line the recessesto'take the spring units but if the material is comparatively-soft it is advisable to fit a metal or'other hard liner into each recess;

These may be provided by making the spring pads in theform of deep cups or ferrules or-theymay be constructed as separate liners adapted to receive spring units having theaforesaid shallow dish form of spring pad.

With means according to the present invention the resistance to load afforded by the spring units is dependent upon the depth of the recesses as it is preferredtomass produce the spring units wherebythe dimensions of the units for each header will be substantially identical; and

by forming theenlargement at the inner end of each pin shank by pinching in its sides therewill be no'risk-of the shanks bending during the operation.

In order that the invention maybe clearly'understood and carried into efiect a practical embodimentof "the spring units according to the'em-bodirnent in which" the spring-pad is-in the form of a-dishedannular washer;

Fig. 4 is a view similar to Fig. 3 showing a spring unit in which the spring pad is in the form of a split ferrule adapted to be pressed into a recess in the header ring until its upper edge is flush with the upper face of the header ring.

Fig. 5 is a view similar to Fig. 4 showing a modified form of spring unit in which the spring pad is in the form of a shouldered ferrule adapted to be pressed into a recess in the header ring until the shoulder of the upper end of the ferrule is hard against the upper face of the header ring.

The hydraulic packing shown in Figs. 1 and 2 of the drawings consists of a header ring and a sealing member 2, both of which are constructed in the conventional form of packings of this type. The sealing member 2 is moulded in rubber or other suitable sealing material with peripheral sealing lips 3 which are maintained in sealing contact with the surfaces of the stufiing box 4 and 3 shaft 5 by the sloping sides of the underface 6 of the header ring.

To permit the free passage of pressure liquid to the cavity between the sealing lips 3 the header ring is provided with a continuous groove 7 in the upper face of the ring, transverse slots 8 to permit the oil to enter groove 7 and holes 9 serving to convey the oil from the groove 7 to the aforesaid cavity between the sealing lips 3.

For the purposes of the present invention the header ring is provided with a further series of holes 10 which are counterbored at their upper or outer ends to provide recesses 11 for the reception of the spring units of the present invention.

Each spring unit of the present invention in its simplest form as shown in Fig. 3 consists in a pin 12 having a fiat head 13 at its outer end a coil spring 14 mounted on the shank of the pin and held in partial compression between the underside of the head 13 and an annular spring pad 15.

The central hole in the spring pad permits the shank of the pin 12 to slide through it and the spring pad is prevented from falling Off the end of the pin by the formation of an enlargement 16 on said end of the pin, said enlargement being formed by peening or pinching in the sides of the shank of the pin after the spring 14 and its pad 15 have been positioned. There is thus provided a unitary structure the components of which will always remain in assembled relationship.

The spring pad 15 in this embodiment is in the form of a shallow dished washer the peripheral diameter of which is greater than the internal diameter of the recess 11 into which the unit is to fit so that in fitting the spring units in the header ring each unit requires to be pressed firmly into its recess. By this means the tendency of each spring pad to expand will prevent the units from falling out of the recesses when the packing is being handled.

The diameter or greatest width of the enlargements 16 and the diameter of the holes 10 is such that each pin is free to slide relative to and through its spring pad as the pin is depressed and released resulting from the application of pressure on the head 13 at its upper or outer end.

Where the material composing the header ring is sufficiently hard there is no need to line the recesses 11 but where a lining is required this may be provided as separate liners in the form of deep cups or ferrules. Alternatively the spring pads may be in the form of deep cups or ferrules so as themselves to act as liners. Examples of these are shown in Figs. 4 and 5. In Fig. 4 the spring pad is in the form of a split ferrule 17 having straight sides integral with a base which has a hole in it that permits the shank of the pin to slide in it but prevents the enlargement 16 from being drawn through. In assembling such a unit in a header ring the same is pressed home until the base of the ferrule 17 is forced against the bottom of its recess.

For the fiat heads 13 in a complete assembly of spring units to be substantially level it is therefore necessary that care is exercised in boring or drilling the recesses 11 to an even depth. To avoid the necessity for this accuracy the spring unit shown in Fig. 5 is used. This differs from the unit shown in Fig. 4 by the formation of a shoulder 18 around the upper edge of its ferrule 17. This shoulder, when the unit is pressed home in its recess in the header ring seats against the upper face of the header ring and thus limits the depth to which the ferrule can be pressed into a recess. Provided, therefore that the recesses are deep enough their depth may vary without affecting the level of the heads 13 of the pins in a complete assembly of units as these must all be substantially at the same level.

We claim:

1. Mechanism for spring'loading a sealing packing comprising a header ring having a plurality of bored and counterbored openings with a shoulder therebetweeu, and an annular sealing member engaged by said header ring and adapted to contact the surfaces to be sealed; said mechanism comprising, a plurality of pin elements each provided with a head portion dimensioned to slide in the counterbored opening and with a shank portion, a plurality of resilient annular pads each received above the shoulder and urged against the surface of the counterbored opening, each of said shank portions extending through the hole of one of said annular pads, and a plurality of springs each abutting one of said head portions and one of said annular pads to spring-load said header ring and said pin elements, each of said springs projecting above one of said annular pads, and an enlarged extension provided at the free end of each of said shank portions and larger than the hole of the corresponding of said annular pads, said enlarged extensions sliding in said bored openings, whereby each of said annular pads is secured to said header element and each of said pin elements is secured to one of said annular pads.

2. Mechanism constructed according to claim 1, wherever the resilient annular pads are dished annular washers.

3. Mechanism constructed according to claim 1, wherein each of said shank portions is provided with a length at most equal to the length of each of said bored and counterbored openings, whereby under maximum load said shank portions remain within said bored openings.

4. Mechanism constructed according to claim 3, wherein the resilient annular pads are dished annular washers.

References Cited in the file of this patent UNITED STATES PATENTS 1,802,552 Corcoran Apr. 28, 1931 2,524,462 Miller et al. Oct. 3, 1950 FOREIGN PATENTS 618,970 Great Britain Mar. 12, 1949

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