US2475026A - Pressure fitting for tube joints - Google Patents

Description

July 5, 1949.

n. P. HYNES EI'AL PRESSURE FITTING FOR TUBE JOINTS 2 Sheets-Shoot 2 Filed Oct. 12, 1s4s 4 jfizxenzors ,flz'brelifffyzzes ZgOflJZOSS layer-neg:

Patented July 5, 1949 I 2,475,026 PRESSURE FITTING FOR TUBE JOINTS Dibrell P. Hynes assignors to Chicago F ing Company, Chicago, 111.,

Delaware and Hugo H. Moss. Chicago, 111.,

orging and Manufactura corporation of Application October 12, 1946, Serial No. 703,028 Claims. (Cl. 285-122) The invention relates to an improvement in tube connections and has for one purpose to provide improved connecting means for tubing or pipes.

Another purpose is to provide connecting means for tubing or pipes having relatively thin walls.

Another purpose is to provide a fluid tight connection for tubing, which includes an elastic member and provides a limited universal movement of the tubing, cushioning the tubing against vibration and metal fatigue.

Another purpose is to provide an improved anchorage ring adaptable for use with joints of the above described type. 1

Another purpose is to provide an improved anchorage ring adapted to be secured to the tubing in response to the compression to which a resilient or elastic member surrounding the anchorage ring is subjected.

Another purpose is to provide such an anchorage ring which is slidable along the tubing before the joint is tightened, but which is firmly positioned on the tubing in response to the tightening of the joint, and resists retrograde movement.

Other purposes will appear from time to time in the course of the specification and claims.

The invention is illustrated more or less diagrammatically in the accompanying drawings wherein:

Figure 1 is an axial section;

Figure 2 is a side elevation of the parts of the joint, in separated or skeletonized position, with parts broken away and parts in axial section;

Figure 3 is a longitudinal section on an enlarged scale through the anchorage ring employed;

Figure 4 is an end elevation of the anchorage rlng;

Figure 5 is a partial axial section illustrating a variant form of anchorage ring;

Figure 6 is an end view on an enlarged scale illustrating the anchorage ring of Figure 5 Figure 7 is a section on the line l! of Figure 6;

Figure 8 is an axial section illustrating the anchorage ring partly applied to the end of the tube;

Figure 9 is a similar section illustrating the anchorage ring as entirely overlyin the tube; and

Figure 10 illustrates a variant form of anchorage ring.

Like parts are indicated by like symbols throughout the specification and drawings.

Referring to the drawings, I generally indicates any suitable member to which the tube connection may be secured. The connection proper ineludes the fitting generally indicated as 2, outwardly screw threaded as at 3, and provided with a hexagonal or multi-faced portion 4, of increased diameter. 5 indicates the cylindrical inner wall of-the bore through the fitting. The bore is outwardly expanded or increased in diameter at the outer end of the fitting as at 6. The portion of the fitting surrounding the larger diameter of the bore is outwardly screw threaded as at I. The end of the fitting is shown as conically concave, as at 8. 9 indicates the end of a tube or pipe, shown as extending within the bore 6. The pipe end is surrounded by the nut Ill with its internal threading It in mesh with the external thread 1 of the fitting 2. The nut has an inwardly cylindrical bore l2 and terminates in an end wall l3 apertured as at l4 to permit the passage of the tube 9. The diameter of the aperture l4 slight- 1y exceeds the external diameter of the tube 9. l5 illustrates a mass or washer of fiexible, resilient, compressible material. portioned to conform to the walls of a pressure chamber which is defined by the exterior of the tube 9, a conic end wall 8 of the fitting 2, the cylindrical bore I2 of the nut l0 and the tapered or conical inner face It of the end wall I3 of the nut. It will be understood that when the mass I5 is subjected to pressure by running up the nut I0 on the fitting 2, the mass 15 substantially entirely or entirely fills the pressure chamber thus formed. It also serves to prevent any metal-tometal contact between the tube 9 and the surrounding parts of the joint. However, it is vitally important positively to anchor the mass or washer [5 on the tube. We find it advantageous to employ an abutment or anchorage which is actually locked against movement along the tube in response to the compression to which the mass I5 is subjected when the nut i0 is tightened on the fitting tube. It is also important that the abutment be initially slidable along the tube, so that it may readily be positioned at any desired position on the tube. It is further important that no special tool or equipment be necessary for applying the abutment.

We obtained the desired result by employing a split ring generally indicated as 20, and shown in detail, in its expanded position, in Figures 3 and 4. The ring may include generally cylindrical portions 2| and 22 connected by an outward fold or bend 23. Preferably the exterior diameter of the folds 23 exceeds the inner diameter of the aperture M of the nut H). The ring is split, as shown at 24 in Figures 2 and 4. The outer edge of at least one of the portions 2| and 22 is preferably It may be initially proformed to provide a gripping connection with the exterior of the tube 9. We illustrate, for example, inwardly bent portions 25 which constitute, in effect, a series of teeth, having sharp, outer, lower corners or edges, as will be clear from Figures 3 and 4. Whereas we illustrate these teeth only along the portion 22 of the ring, it will be understood that they may be employed along the opposite portion 2| as well. However, we find it advantageous to leave the portion 2i without such teeth, since this permits the ready application of the abutment to the end of the tube. When it is applied, the teeth 25 slide along the tube and in fact sink in or enter the surface. However, even when the mass I5 is not subjected to pressure, a retrograde movement of the abutment ring 20 toward the end of the tube is to some extent resisted by the teeth 25. When the ring is applied, as shown in Figure 2, and when the nut ID has been tightened up, as shown in Figure 1, then the pressure to which the mass I5 is subjected is effective to clamp the abutment ring 20 firmly into the surface of the tube. The compression, in practice, holds the abutment ring so tightly against v the outer surface of the tube 9 that the teeth 25 dig into the surface of the tube and strongly resist any tendency of the ring 20 to be pulled along the tube toward the end of the tube. The parts are preferably so proportioned that the gap 24 is never entirely closed, the opposed edges of the ring 20, which bound the gap 24, never coming into abutting or contact relationship.

Referring to the form of Figures 5 and following, we illustrate an anchorage ring which is shown as substantially cylindrical. It may include the generally cylindrical end portions 30 and 3|, which are shown as connected by the outwardly extending bend or ridge-32. The ridge 32 serves as a ferrule, corresponding to the ferrule or ridge 23 of Figures 1 to 4, and extends into the sealing ring I 5. In order to provide edge portions or points to penetrate and lock against and into the outer surface of the tube 9. we illustrate a plurality of teeth 35. These teeth may be formed by inwardly sheared or offset portions of the circumferential anchorage ridge 32. It will be observed, as in Figure 7 that each tooth 35 has a fairly sharp edge or point 36 which is formed and adapted to override the tube end and tube surface when the ring of Figures 5 and following is manually slipped on over the end of the tube 9. However, like the teeth 25 of Fi ures 3 and 4, it resists retrograde movement toward the tube end. When the pressure chamber formed by the fitting 2 and the nut I 0 is reduced in space, in order to compress the flexible ring IS, the result is to force the teeth firmly into the surface of the tube. The split ring then serves as a very efficient anchorage for anchoring the ring I5, and the pressure chamber, against movement in relation to the tube 9. Or to put it the other way, the tube 9 is firmly anchored against withdrawal from the fitting to which it is secured.

In both forms we find it highly advantageous to employ a split ring which is in a broad sense compressible, in that it tends to reduce its diameter in response to the inward thrust of the sealing ring I5, when the sealing ring is subjected to pressure in the above described pressure chamber. The split 24 is never completely closed. We find it advantageous initially to form the rin so that it snugly hugs the surface of the tube 9. However, the fit is preferably not so close, or the spring action so great, as to prevent rea- 4 sonably easy manual application of the anchorage ring to the tube.

It will be realized that whereas a practical and operative device is herein described and illustrated, nevertheless many changes in size, shape, number and disposition of parts may be made without departing from the spirit and content of the invention. It is therefore wished that the description and showing herein be taken as in a broad sense illustrative or diagrammatic, rather than as a limitation to the precise showing herein.

The use and operation of the invention are as follows:

We provide a Joint which will stand high pressures. The mass l5, when the nut I0 is run up on the fitting tube, is subjected to sufficient pressure to lock the abutment ring 20 firmly in place. When 'so locked, it serves as an anchorage which efficiently resists any tendency of the tube 9 to slip out of the connection or any tendency of the connection to be removed unintentionally from the end of the tube 9. The pressure which is necessary to tighten up the joint is itself employed also to lock the abutment or anchorage in place. No special tool is needed, and no additional operation.

It will be understood that the structure herein shown can be widely varied. For example, the number and shape of the teeth employed may be widely varied, or the entire edge or lip of one or both of the portions 2| and 22 0f the ring may be inturned or tapered, in such fashion as to provide a gripping connection between the abutment or anchorage ring and the tube 9 when the mass [5 is subjected to compression. It will be understood that the ring is preferably so shaped that one or both of the portions 2| and 22 respond freely to the inward compression to which they are subjected by the compressed mass l5. The split or division 24 is important. While the members 2! and 22 need not be strictly cylindrical, their general flatness, in axial section, is advantageous, as preventing any bridging or resistance to the pressure exerted through the mass l5. Whereas we have shown the mass i5 as a single piece, it will be understood that it may be assembled of a plurality of separate pieces. The form of Figures 5 and following differs in detail from the form of Figures 1 to 4, but both forms have in common a substantially cylindrical tube provided with teeth, either along an edge of the anchorage ring, or intermediate the edges of the anchor ring. These teeth are advantageously formed to prevent or resist unintended retrograde movement of the anchorage ring from the tube, even before external pressure has been applied to the seal ring l5 and therethrough to the anchor ring.

It is advantageous that the ferrule or anchorage ring be made of thin spring-like stock, so that it can be sprung on the tubing and, when sprung on the tubing, will grip it with a spring action. It is preferably of material composed or tempered to be harder than the tube with which it is used. For example, the anchorage ring may be of steel, stainless steel, beryllium-copper, or other suitable metal or alloy. As will be clear from Figure 8, it is advantageous to have the ring so sprung or biased that when it is applied to the end of the tube 9, the initial entry of the ring about the tube will cause the teeth to engage the tube end. Figure 8 illustrates the anchorage ring as partly applied with the teeth contacting the end of the tube. Figure 9 illustrates the effeet of further movement of the anchorage ring upon the tube. The teeth are actually biting into the outer surface of the tube, and are actually driven into the surface of the tube when pressure is applied through the sealing mass [5. Figure illustrates a variant form of ferrule or anchorage ring in which teeth a, of more or less squared or castellated form, are employed, in the place of the triangular teeth shown in Figures Sand 4.

While all the forms herein shown are efficient and advantageous, the form of Figures 8, 9 and 10 is possibly the most practical. The ferrule or projection 23 advantageously receives the sealing mass or ring l5. The thrust of the square-ended teeth 25a inwardly against the surface of the tube 9 results in a yielding action which permits the ring or ferrule to be slipped readily, even manually, upon the tube end. Movement in the opposite direction, toward the tube end, is strongly resisted. When compression is applied to the yielding mass, the sharp-edged teeth 25a are readily and positively forced into the outer surface of the tube.

An advantageous use of my invention consists in supplying any one of the ferrules or split rings shown, surrounded by a sealing ring, such as I5, the combined ferrule and ring being supplied as a unit, and being ready to apply to the tube.

Whereas I have described my ferrule as slidable on the tube, it should be understood that it is slidable only in one direction. In normal practice it is necessary initially to force the ferrule on the tube by springing it on or opening it up. Once it has been applied to the tube, with the teeth adjacent the end of the tube, it can be advanced along the tube, but it cannot readily be withdrawn from the tube, as the teeth 25 or 25a will tend to bite into the tube.

It will be understood that the ferrule may advantageously be made of harder material than the tube in order to permit it readily to bite into adapted to exert an initial grip on the tubing, and r being adapted, on tightening of the fitting, to bite into the surface of the tubing, thus anchoring the fitting to the tubing, said ferrule having an outwardly extending circumferential projection surrounded by said elastic sealing means.

2. For use with tubing, an anchorage ferrule of relatively thin metal spring stock, said ferrule be- 7 ing split and having circumferentially spaced thereabout a plurality of inwardly extending teeth of a hardness adequate to penetrate the material of the tubing with which the ferrule is used, said teeth being located along one edge only ,of said ferrule.

3. For use'with tubing, an anchorage ferrule of relatively thin metal spring stock, said ferrule being split and having circumferentially spaced about one edge thereof a plurality of inwardly extending teeth of a hardness adequate to penetrate the material of the tubing with which the ferrule is used, the opposite edge of said ferrule being unbroken.

4. For use with tubing fittings comprising a .compression chamber and an elastic sealing means, a split ferrule having edge portions of smaller inside diameter than the outside diameter of the tubing, at least one of said edge portions being provided with circumferentially spacedteeth of a hardness adequate to penetrate the material of the tubing with which the ferrule is used, the ferrule being formed and adapted to exert an initial grip on the tubing, and being adapted, on tightening of the fitting, to bite into the surface of the tubing, thus anchoring the fitting to the tubing, said ferrule having an outwardly extending circumferential projection surrounded by said elastic sealing means.

5. For use with tube fittings comprising a compression chamber and an elastic sealing means, a split ferrule having an edge portion of smaller insidediameter than the outside diameter of the tubing, the ferrule being formed and adapted to exert an initial grip on the tubing, and being adapted, on tightening of the fitting, to bite into the surface of the tubing, thus anchoring the fitting to the tubing, said ferrule having an out- .wardly extending circumferential projection sur- REFERENCES CITED The following referenices are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,822,056 Noble Sept. 8, 1931 2,344,698 Howe Mar. 31, 1944 2,394,351 Wurzburger Feb. 5, 1946

Images