PACKING IN THE FORM OF A TRUNCATED CONE FOR MAKING A WATERTIGHT SEAL BETWEEN THREADED CONNECTIONS

Abstract: Packing (10) for making a watertight seal between two threaded parts constituted by a truncated cone-shaped body made of Teflon<R> whose end of a smaller diameter is inserted in the female threaded connection while the end of larger diameter is inserted in the male threaded connection, screwing movement of the two threaded parts then causing the packing to modify its shape and fit into the two sets of threads said modification of its shape creating a secure and stable watertight seal.

Description: PACKING IN THE FORM OF A TRUNCATED CONE FOR MAKING A WATER¬ TIGHT SEAL BETWEEN THREADED CONNECTIONS The invention concerns a truncated cone shaped packing de¬ signed to make a watertight seal between threaded connections In the normal way tow or cotton threads or plastic tape, especially PTFE (poly etrafluoroethylene ) are used to ensure a watertight seal between threaded connections screwed toge¬ ther to form a joint, such as those on pipes carrying fluids, on taps, in apparatuses such as washing machines, in stove burners and other pieces of equipment too numerous to men ¬ t on. As packing materials of these kinds have no particular shape, structure or dimensions they must be adapted in each case to suit the threaded parts to be joined. Untrained people often find it difficult to use such packing and their efforts may lead to disappointing results. In the case of fluids under pressure, even if only water, or gas for domestic purposes, leaks may occur involving ser¬ ious consequences. An expert manages to make secure connections but even so the job is a long and tiresome one. The above invention seeks to remedy these difficulties as will be explained below. Subject of the invention is a packing to make a watertight connection between two threaded parts and consists of a truncated cone of plastic material whose smaller external diameter is less than the smaller internal diameter of the female threaded part and whose maximum internal diameter is greater than the maximum external diameter of the male threaded part . It follows that by placing the invented packing between the two parts to be connected, inserting its end having the smaller diameter inside the female threaded part and insert¬ ing the male threaded part inside the end of the packing with the greater diameter, the act of screwing the two threa¬ ded parts together will adapt the packing to the two connect¬ ing threads producing a safe and efficient seal due to the shape which che compressed plastic material assumes. Starting from its smaller end, the thickness of the sides of the truncated cone gradually increase to facilitate adherence between the two threaded parts, male and female, when they are being screwed together, and to. improve the resulting seal. Where its diameter is greatest the truncated cone has an ex¬ ternal rim both for greater strength and to provide a grip for the fingers when the packing is being mounted. In one type of execution the truncated cone is cut along a geometric plane in line with the axis of the packing. This cut helps the packing to adapt itself to the male and female threads on the two connecting parts. The effect of screwing up these two parts presses the two opposing edges of the cut together so that packing contin¬ uity is restored. One type of execution includes, on one of the two transver¬ sal edges created by the cut, a thin flap of constant thick- ness whose inner surface is continuous with the inner sur¬ face of the truncated cone and whose width is practically equivalent to the length of the above edge. Said flap lies over the cut and therefore over the outer surface of the wall of the truncated cone following on from said cut. Screwing movement brings the edges of the cut closer toge¬ ther and causes the flap to slide over the surface of the truncated cone achieving maximum adaption to the opposing interacting threads and thereby making for a secure water- tight seal. In some cases the cut in the wall of the truncated cone can extend for the whole length of said wall including the rein¬ forcing rim, or else stop short of the rim thereby main¬ taining its continuity. A suitable material for th_is packing is Teflon (PTFE) or a similar type. The advantages of the invention are clear. The packing can be mounted by anyone, however unpractised in the art, ensuring perfect watertightness while applica- tion is a quick and simple process. It can be used in thread ed connections generally, with practically the same results, of watertightness, easy application and reliability, as thos obtained by using the ordinary flat, ring-type packing for connections having transversal circular walls. Characteristics and purposes of the invention will be made still clearer by the following examples of its execution il- lustrated by diagrammatic figures. Fig. l: A partially cut away view of the truncated cone packing subject of the invention. Fig.2: Plan view of the above. Fig.3: Side view of the truncated cone packing, subject of the invention, opened on an axial geometric plane with covering flap. Fig. : Plan view of .the above. Fig.5: Side view of the invention opened on an axial geo¬ metric plane except for the base strengthening rim. Fig.6: Plan view of the above. Figs.7 and 8: Side and plan view of the packing shown in Figs. 5 and 6 with the flap lying over the outer surface of the truncated cone. The teflon packing 10 has a monolithic body shaped like a truncated cone. The thickness 14 of the walls 13 decreases steadily from the base 11 of a larger diameter to the base 12 of a smal¬ ler one . The larger base is finished with an external rim 15 pro¬ jecting outward. The external diameter of the base 12 is less than the lesser diameter of the thread in the female part to be screwed on to the male part. The internal diameter of the base 11 is greater than the greater diameter of the thread on the male part. It is therefore possible to interpose the packing between the female part and the male part to be connected to it so that the latter penetrates inside the larger hole in the packing, while the end of said packing where the hole is smaller penetrates inside the threaded hole in the female part . When the two parts are screwed together the plastic pack¬ ing adapts its shape to fit between the two interacting threads. . Adherence to each thread is facilitated and strengthened by increasing thickness of the walls from the smaller Base to the larger base, said thickening creating a wedge-like effect that ensures the perfect seal. The outward projecting rim 15 helps the fingers to keep hold of the packing and, when screwing is completed, can also act as a limit point of reference to the female part assisting it to draw the packing round the male thread. The packing 19, with projecting rim 20 on the larger base, as seen in Figs. 3 and 4, is substan ially the same as the one in Figs. 1 and 2 except that the wall 21 of the truncated cone is seen to be cut on an axial geometrical plane that creates the transversal edges 22 and 23. A thin flap 24, of constant thickness, originates from one of the edges 23, said flap lying flush with the internal surface of the truncated cone, its width being practically the same as the length of the edge from which it originate Figs. 5 - 8 show a packing 30 similar to that in Figs. 3 and 4 except that the cut along the wall of the truncated cone 33 leaves intact the projecting rim 34 round the base of larger diameter. The cut creates the transversal edge 31 while the wall of the truncated cone continues in the thin flap 36,of con¬ stant thickness, flush with the internal surface of the truncated cone and of a width practically equivalent to the length of the wall of said truncated cone. The triangular cross section of wall 33 gradually joins up with the rectangular cross section of the flap 36. Radial sections, shown on axes a, b in Fig. 6, make cleare the shape of the truncated cone wall close to the flap 36 (section along axis b) and at the transversal edge 32 (se tion along axis a). By applying to the connection the packings as described with a cut along one generatrix of the truncated cone, wh the threaded parts are screwed together the inner surface of the flap, connected to one transversal edge made by th cut, slides over the outer surface of the packing beyond the cut, covering it and restoring surface continuity to the trun ¬ cated cone.

Claims: CLAIMS 1. Packing (10) (19) (30) for making a watertight seal at the connection between two threaded parts characterized in that it consists of a truncated cone of plastic material whose smaller external diameter is less than the smaller internal diameter of the threaded female part and whose lar¬ ger internal diameter is greater than the larger external diameter of the male threaded part so that, by placing the packing between the two part to be joined in such a way that the end of the packing with a smaller diameter penetrates the threaded female part, and the threaded male part pene¬ trates the end of the packing of larger diameter, screwing the two threaded parts together will cause the packing to adapt and fit closely round the two threads creating a se- cure and efficient seal due to plastic adaption of the ma¬ terial. 2. Packing for making a watertight seal at the connection between two threaded parts, as in claim 1, characterized in that, starting from its smaller diameter, there is a gradual increase in t-he thickness (14) of the walls ( 13) (33) of the truncated cone, the purpose of this being to facilitate ad¬ herence and matching between the two male and female threads of the parts to be connected by being screwed together, and to improve the security of the. seal. 3. Packing for making a watertight seal at the connection between two threaded parts, as in claim 1, characterized , in that, at the truncated cone's larger base (11), there is an external outward projecting rim (15) (20) (34) for extra strength and to assist the fingers to grip the packing while it is being mounted. 4. Packing for making a watertight seal at the connection between two threaded parts, as in claim 1, characterized in that there is a cut made in the body of the truncated cone on a geometric plane passing along its axis, to assist adaption of said packing to the male and female threads, the two edges (22) (23) on each side of the cut being brought together by the screwing movement of the two threaded parts so as to restore continuity of the wall ( 14) (21) of the truncated cone. 5. Packing for making a watertight seal at the connection between two threaded parts, as in claim 4, characterized in that on one of the two edges (22) (23) made by the cut, a thin flap (24) (36), of constant thickness, is made, the inner surface of said flap being continuous with the inner surface of the truncated cone, its width being practically the same as the length of the wall (21) (33) of the trunca¬ ted cone, said flap matching with the outer surface of said wall (21) (33) so that, due to screwing motion, the edges (22) (23) (31) (32) of the cut are brought together and the flap (24) (36) slides over the outer surface of the wall of the truncated cone beyond the cut thus restoring continuity of said wall (21) (33), obtaining maximum adaption to the opposing interacting threads, and a perfect watertight seal between the two threaded parts. 6. Packing for making a watertight seal at the connection between two threaded parts as in claims 3, 4 ,characterized in that the cut is made along the whole length of the wall (33) of the truncated cone except for the circular reinforc ing rim (34) which remains intact. 7. Packing for making a watertight seal at the connection between two threaded parts as in claims 1-6 ,characterized in that said packing is made of polytetrafluoroethylene .

Inventors: BRUNO SALVATORE, BRUNO, SALVATORE
Applicants: SALVATORE BRUNO, BRUNO, SALVATORE
Application year: 1989
Main classification: F16L15
IPC codes: F16L15