US2730136A - Thread protectors - Google Patents

Description

Jan. 10, 1956 s. L. PHILLIPS THREAD PROTECTORS Original Filed May 6, 1950 fiG.3

INVENTOR. Same-y Z PHILLIPS Ari-0e 5' United States Patent THREAD PROTECTORS Stanley L. Phillips, Parkview Village, Ohio, assignor to Wedge Protectors, Inc., Cleveland, Ohio, a corporation of Ohio Original application May 6, 1950, Serial No. 160,435, new

Patent No. 2,627,877, dated February 10, 1955. Divided and this application November 1, 1952, Serial No. 318,262

1 Claim. (Cl. 138-96) This invention relates to thread protectors of the kind made from sheet metal and adapted to be applied to the ends of pipes, conduits, fittings and machine parts to protect the screw threads of such members against damage from blows or contamination by foreign matter during handling, shipping and storage.

This application is a division of original application Serial No. 160,495, filed May 6, 1950, now Patent No. 2,627,877, granted February 10, 1955.

Thread protectors of this kind are usually discarded as scrap material after a single use and this makes it necessary that the protectors be manufactured as economically as possible. There are, however, certain requisites which must be met in such thread protectors and which have heretofore prevented the manufacturing cost from being reduced below a certain minimum.

One of these requisites is a certain rigidity and strength needed to protect the thread against blows and which has heretofore been obtained by selecting the weight or gauge of sheet metal stock which will provide the required rigidity and strength in the protectors made from such sheet metal stock. Another such requisite is that the protector have a relatively smooth and finished shape which is devoid of burrs and sharp edges, such that the protectors and the pipes or machine parts to which they are applied, can be handled safely and without danger of causing personal injury or torn clothing. To provide the protectors with such a smooth and finished shape has heretofore required additional forming and trimming operations which have materially increased the cost of manufacture.

The present invention deals successfully with these problems and provides a novel construction for a sheet metal thread protector which will permit the protector to be manufactured more economically and yet without sacrifice in its strength and rigidity or in the smoothness and regularity of its shape.

Another object of this invention is to provide a novel construction for a thread protector of the sheet metal type, in which a hollow annular rim integrally formed on the outer end of the sheet metal sleeve of the protector provides an annular seat for engagement with the end of the threaded member and also reinforces and stiifens the protector so efiectively that it can be manufactured from a lighter gauge of sheet metal without any material sacrifice in rigidity or strength.

A further object is to provide an improved thread protector of the character mentioned in which the hollow annular rim is of a radial width such that the periphery thereof extends beyond the periphery of the threaded member and which rim periphery has knurling extending therearound to facilitate obtaining a secure grip on the protector for applying the same to the threaded member but more particularly for removing the protector from such threaded member.

Still another object is to provide an improved thread protector of this character in which a packing is connected with the protector by having a holding portion re 2,538,135 Patented Jan. 10, 1956 tained in the hollow annular rim and such packing is adapted for sealing engagement with the end of the threaded member to which the protector is applied.

Yet another object is to provide an improved thread protector of the kind above referred to and intended for application to an internally threaded hollow member having an internal chamfer, in which the sheet metal of the sleeve portion of the protector defines an axially inwardly converging annular taper adjacent the hollow annular rim for seating engagement with the internal chamfer of the threaded member.

Other objects and advantages will be apparent in the following detailed description and in the accompanying sheet of drawings in which:

Fig. 1 is an elevation, with portions in longitudinal section, showing one form of the improved thread protector of the present invention applied to an internally threaded pipe fitting;

Fig. 2 is an outer end view of the thread protector of Fig. 1 showing the same in detached relation; and

Fig. 3 is an elevation, with portions in longitudinal section, showing a thread protector similar to that of Fig. 1, but which includes a packing element.

In the embodiment of the invention illustrated in Figs. 1 and 2 a hollow member or pipe fitting 31 is shown, such as a coupling having an internal thread 32 therein with a thread protector 33, of the inside type and embodying the present invention, applied to such coupling in protective relation to the thread thereof. The coupling 31 is also provided with an inwardly converging annular axial chamfer 34 adjacent its outer end and with which the thread protector 33 cooperates, as will be presently explained.

The thread protector 33 is a substantially cup-shaped hollow sheet metal member having a sleeve portion 35 carrying an external helical thread 36 adapted for screwed engagement with the thread 32 of the coupling 31. The protector 33 includes a transverse end wall 37 at the inner end thereof and, at its outer end, is provided with a hollow annular bead or rim 38. Between the hollow rim 38 and the thread 36, the protector 33 is provided with an inwardly converging annular axial chamfer 39.

In accordance with one important feature of the pres ent invention, the hollow annular bead or rim 38 is integrally connected with, and formed by the sheet metal of, the outer end of the sleeve portion 35 and is substantially radially outwardly offset from the sleeve portion so as to occupy a position in an outwardly overhanging relation such that it will engage the annular end face 40 of the fitting 31 when the protector is screwed onto the thread 36. The hollow annular rim 38 is formed by the sheet metal of the outer end of the sleeve portion 35 being deflected so as to extend in an outwardly offset and reversely curled relation as shown in Fig. 1 of the drawing. Such deflection of the sheet metal of the outer end of the sleeve portion 35 into this reversely curled relation to define the hollow annular rim 38 can be accomplished by any suitable drawing, forming or spinning dies by which sheet metal operations of this kind are accomplished.

The hollow annnular rim 38 is defined by integral Wall portions of the sheet metal sleeve 35 of the protector and which include a substantially radially outwardly extending annular wall portion 38, an axially extending annular wall portion 38 and a substantially radially inwardly extending annular wall portion 38. These annular wall portions 38 38 and 38 are integrally connected continuous portions of the sheet metal located at the outer end of the sleeve 35 and constitute the above-mentioned outwardly deflected and reversely curled sleeve portions which define the hollow annular rim 38. As shown in Fig. 1, the inwardly extending annular portion 38 approaches, but preferably does u not engage, the wall defining the main portion of the sleeve 35.

When the thread protector 33 is applied to the fitting 31, the outwardly offset hollow annular rim 38 engages the end face 40 of the fitting and, in cooperation with the thread 36, produces a wedged or locked engagement on the fitting for retaining the protector thereon. The hollow annular rim 38, and particularly the inwardly deflected annular portion 38 thereof, will be capable of some springing or yielding when the protector is applied to the fitting for producing this locked C'l'iCCt and also as the result of blows delivered against the outer end portion of the protector during handling or shipping of the fitting. Since the annular rim 33 is hollow and has this limited yielding or springing characterist'ic, it will readily absorb such blows or jars and prevent the same from damaging the threaded end of the fitting.

As another feature of this invention, the improved thread protector 33 is constructed so that the hollow annular rim 38 will have a radial width such as to locate the outer periphery of the rim at a point outwardly of the outer surface or periphery of the fitting 31 and this outer periphery of the rim is provided with knurling 41. When the hollow annular rim 38 has such an increased radial widthand carries the knurling 41 on its outer periphery, an appropriate tool or a secure handgrip can be applied to the protector for more easily unscrewing the same from the threaded fitting 31' when the protector is to be removed.

. One important advantage resulting from the above described construction for the thread protector 33 is that the hollow annular rim 38 reinforces and stiffens the sheet metal sleeve 35 to such an extent that the protector can be made from a much lighter gauge of sheet metal stock than has heretofore been practical. For example, it is pointed out that when the thread protector 33 is of a size to be applied to a pipe of approximately 2% inch nominal size, it was necessary heretofore to make the protector out of sheet metal stock of 13 gauge. With the improved construction here shown for the protector 33, the increased rigidity I afforded by the hollow annular rim 38 makes it possible to construct the protector out of sheet metal stock of 16 gauge, or even a lighter gauge, without materially sacrificing any strength or rigidity in the protector. The lighter gauge of sheet metal stock now used can be more easily formed than the heavier gauge heretofore used and therefore results in an advantage in die expense, both as to initial die cost and die maintenance.

Another important advantage resulting from the hollow annular rim 38 is a manufacturing advantage in that a protector of a smooth and regular shape and devoid of dangerous burrs and sharp corners can be made with fewer manufacturing operations. This is possible because during the manufacture of the thread protector 33 the sheet metal at the outer end of the sleeve 35 can usually be formed to its outwardly deflected and reversely curled condition during a single forming operation and, since the extreme annular end of the sleeve 35 is disposed in the finished protector in a position where it will not be engaged by the hands or clothing of the workmen handling the protector or the pipe carrying the same, it will not require any trimming. or smoothing operation as has heretofore been necessary to remove or eliminate such dangerous burrs and sharp edges.

The above-mentioned inwardly converging axial taper 39, provided on the thread protector 33 between the rim 38 and the helical thread 36 thereof, constitutes another important feature of this protector because it cooperates with the internal chamfer 34 to produce new results including the centering of the outer end of the protector onthe fitting .31. The axially tapered portion 39 is constructed so that its outer end will provide an annular shoulder or edge 39 of a diameter to wedgingly engage in the internal chamfer 34 when the protector 33 is screwed into the fitting 31 for the distance necessary to cause the hollow annular rim 38 to engage the end face of the fitting. This wedging engagement of the annular shoulder or edge 39 not only centers the outer end of the protector in the outer end of the fitting 31 but forms an annutar seal by the metal-tometal engagement between the protector and the fitting at this point. Such a seal is desirable because it enables the protector to exclude foreign matter from the thread 32 which might otherwise corrode or contaminate such thread.

In Fig. 5 of the drawing a thread protector 43 is shown which is of a construction similar to the thread protector 33 described above and in which the corresponding parts are designated by the same reference characters. The thread protector 43 is used in the same manner and affords the same advantages as the above-described protector 33. In addition, the thread protector 43 carries a packing 44 at its outer end and which, is held in connected relation with the protector by having a holding portion 44 retained or locked in the annular recess of the hollow annular rim 38. The packing 44 also includes a ring portion 44 which projects from the rim Y38 and is engageable with the end face 40 of the coupling 31 when the protector is fully applied thereto.

The packing 44 may be a ring formed or" any material suitable for sealing purpose between the protector 43 and the fitting 31 such as paper, asbestos or other fibrous material, rubber or rubber-like material, or a soft metal such as brass, copper, or aluminum. This packing ring can be assembled into connected relation with the protector 44 without requiring any additional manufacturing operation, by simply placing the packing ring in a position to have the holding portion 44 thereof engaged and confined in the recess 45 of the hollow rim 38 when the sheet metal of the outer end of the sleeve 35 is deflected into the above-described reversely curled relation. Such deflection of this portion of the sleeve 35 causes the annular portion 38 of the hollow rim 33 to engage the packing ring 44 and press the same against the main wall of the sleeve 35 with the relatively enlarged retaining portion 44 confined-or locked in the recess 45.

When the protector 43 has been applied to the fitting 31, the packing 44 will assist in causing the protector to be securely held on the fitting and will also assist in centering the outer end of the protector in the open end of the fitting. This packing will also serve the purpose of absorbing some of the blows and shocks which are delivered against the outer end of the fitting during handling and shipping and will form a seal at the outer end of the fitting which will assist in excluding foreign matter which might otherwise corrode or contaminate the thread 32.

From the accompanying drawing and the foregoing detailed description it will now be understood that this invention provides an improved construction for a thread protector to be used on a threaded fitting, pipe end, machine part or other member and which protector can be more economically produced because the integral hollow annular rim formed on the outer end of the protector stiffens and reinforces the same so' that a lighter gauge of sheet metal can be used. It will also be seen that this hollow annular rim has a springing and yielding action for absorbing blows which might otherwise damage the threaded end of the member and this rim of itself, or assisted by a packing member or an annular chamfer, also forms a seal with the outer end of the member to which the protector is applied and accomplishes a centering and locking cooperation with such outer end by which the protector is held against lateral shifting or accidental unscrewing. Additionally, it will be seen that in the improved protector the hollow annular rim is'. of a radial width. and carries. knurling such that the peripheral edge thereof will extend beyond the periphery of. the member to which the protector is applied and will facilitate the application or removal of the protector by the use of a suitable tool or a handgrip. it will be seen, furthermore, that the use of the hollow annular rim at the outer end of the protector not only produces a stronger and more rigid protector from a lighter gauge of sheet metal, but the radially deflected and reversely curled relation of the sheet metal of the outer end of the sleeve which forms this hollow annular rim eliminates the need for trimming the sheet metal, or performing other machine operations thereon at this point which have heretofore been necessary to remove dangerous burrs and sharp edges.

Although the improved thread protector of the present invention has been illustrated and described herein to a somewhat detailed extent, it will be understood, of course, that the invention is not to be regarded as being limited correspondingly in scope, but includes all changes and modifications coming within the spirit of the invention and the language of the claim hereof.

Having thus described my invention, I claim:

A thread protector for application to a hollow member having a helical thread on the inside thereof and also having an internal annular chamfer at its outer end comprising, a one-piece sheet metal sleeve having a group of thread elements thereon and engageable with said helical thread for retaining the protector in connected relation with said member, the sheet metal of the extreme outer end of said sleeve being deflected so as to define a radially ofiset hollow annular rim formed by continuously connected annular wall portions consisting of axially spaced first and second substantially radially extending flange portions and an axially extending portion connecting said second flange portion with said first flange portion, said hollow annular rim forming a stilfening means and an external annular end seat on the outer end of said sleeve and being of a radial width such that the outer periphery of said rim projects beyond the outer periphery of said member, said first flange portion forming an end wall on said protector at the outer end thereof and said second flange portion forming said external annular end seat on said protector for seating engagement with the end face or" said member, said second flange portion being an inturned annular flange portion terminating in a free annular edge presented toward and lying adjacent to the main wall of said sleeve at a point between said first flange portion and said thread elements such that said free annular edge is relatively shielded from injurious personal contact therewith, the sheet metal of said sleeve also defining an axially inwardly converging external annular taper on said protector adjacent said annular rim and adapted for seating engagement against the internal annular chamfer of said member, said free annular edge being spaced from said main wall of said sleeve by an intervening annular slot, and a packing retained in said hollow annular rim and having an annular portion projecting from said hollow rim through said annular slot for continuous annular sealing engagement with the end of said member adjacent the outer end of said chamfer.

References Cited in the file of this patent UNITED STATES PATENTS 2,001,248 Greene May 14, 1935 2,022,189 Engstrom Nov. 26, 1935 2,055,646 Bosley Sept. 29, 1936 2,074,231 Meacham Mar. 16, 1937 2,098,087 Engstrom Nov. 2, 1937 2,121,436 Lytle June 21, 1938 2,385,408 Engstrom Sept. 25, 1945 2,471,716 Bell May 31, 1949

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