JPH0764362B2 - End cap for pipe protection - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw protection device, and more particularly to a protective end cap for protecting an external thread of a pipe at an end of a pipe, a tube, a casing or the like. is there.

PRIOR ART AND PROBLEMS TO BE SOLVED BY THE INVENTION US Pat. No. 4,097,756 discloses a protective end cap made of resin. The end cap includes a radially inwardly curved end that covers the surface of the threaded end of the pipe. The curved end made of resin provides some protection to the threaded end of the pipe from light axially directed impact forces, which may damage the threaded end. When damage occurs, it may be necessary to tap the damaged screw again, or cut the damaged pipe and rethread the pipe.

It is also known to have a metal end cap having an inner peripheral thread that threadably engages the outer thread of the pipe. Axial impact forces on such metal end caps damage the threads, resulting in staggered outer threads of the pipe that interfere with removal of the end cap. For damage to such threads, it is necessary to either re-tap the damaged thread or cut and remove the end cap and rethread the pipe end.

Means for Solving the Problems The main object of the present invention is to provide an end cap for protecting a pipe for protecting an external thread at an end of a pipe or the like.

This object is achieved by providing the following pipe protection end cap for protecting the external threads formed on the end of the pipe.

A sleeve, a resin tubular core provided on the inner peripheral surface of the sleeve, which is insertable into the sleeve and is capable of screwing with an external thread of a pipe end,
A fixing means for connecting and fixing the sleeve and the core to each other to form an end cap for protecting the pipe, and a state in which the end cap is mounted on the pipe and is positioned outside the pipe end face in the axial direction of the pipe. And an annular metal plate that covers the end surface of the pipe, the end of the sleeve and the end of the core each have an extension portion that covers the end surface of the pipe from the outside in the axial direction of the pipe, and the end cap is attached to the pipe. In this state, the sleeve end extension is located further outside the annular metal plate in the axial direction of the pipe, and is sandwiched between the annular metal plate and the sleeve end extension to extend the core end. There is a full-thickness portion of the portion or a portion corresponding to a part of the full-thickness, and when an impact force acts on the pipe end portion, the impact force is absorbed by the deformation of the sandwiched thickness portion. In addition, sandwiched thickness Pipe protective end cap thickness dimension of the portion is set.

According to one aspect of the invention, the sleeve and core have end extensions that are interlocked with each other and are curved radially inward. When assembled by threading the end cap to the pipe end, the curved core end extension sealingly engages the pipe end surface to provide a structure to cover and protect the pipe end surface.

According to another aspect of the present invention, there is a portion corresponding to a total thickness portion of the core end extension portion or a portion corresponding to a part of the total thickness, sandwiched between the annular metal plate and the sleeve end extension portion. . That is, it suffices if there is a core end extension part having a thickness capable of absorbing impact force applied to the pipe end part between the annular metal plate and the sleeve end extension part. There are two types of arrangements. First, the annular metal plate is in contact with both the core end extension and the pipe end surface (that is, the core end extension is in contact with both the annular inner surface located on the pipe end face side and the pipe end face). hand),
It is a form arranged between the both. In this case, the entire thickness of the core end extension exists between the annular metal plate and the sleeve end extension. The second is that the annular metal plate is embedded in the core end extension without contacting the pipe end face, and between the annular metal plate and the sleeve end extension and between the annular metal plate and the pipe end face. , A part of the total thickness of the core end extension portion (a part of the total thickness in the pipe axis direction) is present, in this case, between the annular metal plate and the sleeve end extension portion. Existing core end extension (a part corresponding to a part of the total thickness)
Need only be set to a thickness that is large enough to absorb the impact force applied to the pipe end, and the remaining thickness of the core end extension that exists between the annular metal plate and the pipe end face (total The portion corresponding to the remaining part of the thickness) can be made smaller than the previous thickness portion (the thickness portion existing between the annular metal plate and the sleeve end extension portion). This is because the latter thickness portion is provided mainly to form the recess (or groove) for holding the annular metal plate in the core end extension portion. Also, the thickness of the core end extension that should be present between the annular metal plate and the sleeve end extension can be made sufficiently large, but it is not a waste of material to make it too large. Occurs at the end of the pipe depending on the thickness of the pipe, the material of the core (type of resin), the transport (transport) means of the pipe, the packaging form of the pipe, the transport (transport) distance, etc. It is set by predicting the magnitude of the impact force applied. The thickness cannot be uniquely determined, for example, by considering only the wall thickness of the pipe, and must be set while considering the above-mentioned various conditions. The point is that the impact energy expected to act on the pipe should be absorbed by the deformation of the entire thickness portion of the core end extension portion or a portion corresponding to a part of the total thickness, and in this sense. The thickness dimension of the core end extension cannot be defined in advance.

According to still another aspect of the present invention, the sleeve and the core are connected and fixed to each other by the fixing means. Various fixing means are conceivable, for example, a structure in which a protrusion formed on the peripheral wall of the core is received in an opening formed in the peripheral wall of the sleeve, an end surface portion of the sleeve end extension portion (that is, curved from the sleeve body). Then, a plurality of notches are formed in the end surface portion of the sleeve end extension portion that is oriented in the direction perpendicular to the axis of the pipe, and a hook-shaped protrusion is provided in the core end extension portion to form the notch. A structure in which a plurality of spline projections are provided on the outer periphery of the core, and a plurality of grooves corresponding to the spline projections are provided on the inner circumference of the sleeve to fit the spline projections and the grooves. There may be fixed joining of the sleeve and the core with an adhesive, an interference fit (pressure fit), and the like.

According to one embodiment of the invention, the core end extension comprises an integral closure (closure membrane) for closing the core. The closure is further provided to provide a doorway through which it can pass.
Equipped with one or more tear flaps (lid or valve disc).

One of the advantages of the present invention is to provide an end cap that protects the external threads at the end of a pipe or the like, which is of simple shape and construction yet is simple to manufacture. This advantage can be obtained by using a common sleeve for one type of structure and inserting and fixing various cores having different internal thread shapes into the sleeve. The inner thread shape is
Aligned with pipe ends with various shapes of external threads on the market.

Another advantage of the present invention is to provide an end cap composed of a core and a sleeve, the core and sleeve having an end cap when attached to the pipe end face.
There is a new combined end extension that covers and engages the pipe end face. The end extension of the end cap is suitably reinforced by an annular metal plate (washer) to prevent the externally threaded pipe end from being damaged by the force applied to the front end of the end cap. Protect. If the end of the pipe is damaged, consider that it may require costly repair work, such as tapping the outer thread again or cutting the end cap to remove and rethreading the end of the pipe. Therefore, the advantage of protecting the pipe end is great.

The invention and the advantages of the invention are further clarified by the following examples. Although the embodiment of the present invention described in the claims is shown in FIG. 6, except for the end cap tip end structure incorporating the annular metal plate, FIG.
It is the same as that shown in FIG. 5, and in this sense, the entire diagram will be described as an example.

EXAMPLE Reference is made to FIGS. 1 and 2. Shown is a pipe protecting end cap 10 that protects a Buttress-shaped external thread 12 at either end of the pipe, conduit, casing, etc., shown at 14. The end cap 10 includes an outer sleeve 16 and an inner core (tubular core) that are assembled together.
It consists of two parts with 18.

The outer sleeve 16 may be formed of a stiff material such as steel, preferably cylindrical over most of its length. Further, the sleeve 16 has an outer end extension 20 (sleeve end extension) 20 which is radially inwardly curved and extended to cover the end face 22 of the pipe 14 when the end cap 10 is attached to the pipe end.

The inner core 18 is preferably formed of a suitable resin material having excellent impact resistance, and when the end cap 10 is screwed into the end of the pipe, the tapered outer peripheral surface of the pipe 14 ( That is, the core is provided with a tapered inner peripheral surface formed with an inner screw 24 that is screw-engaged (screw-engaged) with an outer screw 12 formed on an outer peripheral surface that is gradually narrowed toward the tip of the pipe. . The end caps are hermetically held to the pipe by externally engaging external threads 12 and internal threads 24. Therefore, the pipe threads are not exposed to moisture. further,
The core 18 has an outer peripheral surface 26 and a curved outer end 28.
The outer end 28 conforms to the inner peripheral surface 30 of the sleeve 16. The outer end portion 28 also has a portion (core end portion extension portion) 27 that projects and extends inward in the radial direction. The core end extension 27 is generally
It is sandwiched between the end face 22 of a 0.10 cm (0.04 inch) thick pipe 14. Further, the core 18 has an inner end edge (left end edge in the figure) 29 having a diameter larger than that of the end 33 of the sleeve 16 so that the end of the sleeve 16 is not damaged by an external force, that is, an impact force. For protection and handling, the end of the sleeve 16 does not damage the exposed threads of other pipes 14. The inner edge 29 has a tapered edge 31 that diverts the impact force applied thereto.

The sleeve 16 and core 18 are immovable relative to each other by suitable fastening means such as gluing, interference fit, or one or more openings 32 in the sleeve as shown in the drawings (which together with the projections 34 make up the fastening means). Fixed. The opening 32 receives a projection 34 of the core which is in a complementary relationship with the opening 32 and which is pressed by the sleeve when the core is fit-engaged with the sleeve. The inner diameter of the sleeve 16, the outer diameter of the core 18, and the tapered inner peripheral surface 24 of the core 18 with the inner thread 24 are used to seal the end cap to the pipe with a suitable tool such as a pipe wrench, not shown. When screwing in, ensure that the end cap 10 is sealed tightly to the pipe 14 with sufficient force so that the outer screw 12 and the inner screw 24
Is arranged along the sleeve 16 having high rigidity. Although the opening 32 and the protrusion 34 as fixing means for connecting and fixing the sleeve 16 and the core 18 to each other are shown as being circular, they may be formed in other suitable shapes such as a square and a rectangle. it can.

Please refer to FIG. 3 and FIG. Parts similar to those shown in Figures 1 and 2 are labeled with the same number (eg 16 ', 16 ") with a dash and a double dash respectively. Invention end cap 10 ', 1
0 ″ is a pipe with different types of external threads 1
It is shown mounted on 4 ', 14 ". The outer sleeves 16', 16" are substantially identical to the sleeve 16 of FIG. The inner cores 18 ', 18 "have the same outer shape, but have inner peripheral surfaces formed with inner threads 24', 24" having different shapes respectively corresponding to the outer threads 12 ', 12 "of the pipe. One type of common sleeve 16, 16 ', for manufacturing pipe protection end caps with various types of external threads
16 ″ and cores 18, 18 ′, 18 ″ having different shapes may be prepared. The inner core has a common outer surface 26,26 ', 26 "
And the internal threads 24, 24 ', 24 "of different shapes shown in the drawings to match the different externally threaded pipes 14, 14', 14" or other commercially available pipes, respectively. And a peripheral surface.

In the end cap 10 ″ of FIG. 4, the left end of the end cap is protected at the inner end (left end in the figure) position of the end cap to ensure that the end cap seals tightly. A further modification has been made for this, which is carried out by a metal ring 23. The metal ring 23 is fixed to the end cap by any suitable means such as spot welding. It is on the inside end of the 18 ″ and protects it, helping to keep the end cap sealed at the inside (ie, left) end.

Referring to FIG. A core end extension portion having a sufficiently large wall thickness that is extended from the core outer end portion 28 in a radial direction with respect to the outer end portions 28, 28 ', 28 "of the curved core shown in Figs. It has been modified to form 27. In this example, the core end extension 27 is approximately the pipe thread pitch diameter.
1.5 times the width (thickness) or approximately 0.46 cm (0.18 inch)
Has a width of. With the core end extension portion 27 having this thickness, the impact force applied to the sleeve end extension portion 20 moves the end cap 10 over a considerable axial distance relative to the pipe, Most of the screws 24 shear. This consumes most of the impact energy and protects the pipe threads well.

Reference is made to FIG. 6 (an example of the present invention described in the claims). An annular metal plate 36 such as a washer is embedded and attached in the core end extension portion 27. The annular metal plate 36 is positioned in an annular groove formed along the inner circumferential direction of the core end extension portion 27, and a pair of opposed annular surfaces that form the inner surface of the annular groove together with the bottom of the annular groove. Is in contact with. This annular groove is for holding the annular metal plate 36 against the core end extension portion 27. Further, the annular surface of the core end extension portion 27 and the annular metal plate 36 are connected to the pipe 14
Along a plane that is substantially perpendicular to the axis of. According to the arrangement relationship of the annular metal plate 36 as described above, the portion sandwiched between the annular metal plate 36 and the sleeve end extension portion 20, that is, the core end extension portion (first portion) 27 is The extension
27 thickness and the remaining thickness of the core end extension (second
(Portion) 54 is a portion corresponding to a part of the total thickness including the thickness of 54. The annular metal plate 36 may be integrally embedded in the core end extension portion 27 when the resin core is manufactured by molding. Alternatively, a circlip-type split annular metal plate (washer) 36 that can be reduced and inserted into the groove may be fitted into the annular groove of the core end extension portion 27. In this case, upon mounting, the split annular metal plate is once contracted and applied to the annular groove, and then released, the split annular metal plate expands to fill the annular groove. The end extension portion 20 of the sleeve 16 and the end extension portion 27 of the core 18 cover the end surface of the pipe 14, and the annular metal plate 36 is aligned with the pipe end surface 22 and covers the pipe end surface 22 from the pipe axial outside. Pipe 14
Protects. Therefore, for example, the external force applied to the end extension portion 20 of the sleeve 16 by dropping the pipe 14 to the attached pipe end portion of the end cap 10 causes the sleeve end extension portion 20 and the core end extension portion 27. And the annular metal plate 36 is pressed toward the pipe end face 22 side, and is absorbed by the sleeve end extension 20, core end extension 27 and annular metal plate 36. The absorption of this force prevents damage to the outer screw 12 and the inner screw 24. If such damage is not prevented, it will be necessary to tap the outer screw 12 again, or to cut the end of the damaged pipe and perform thread cutting on the end of the pipe again. The remaining thickness portion (second portion) 54 of the core end extension portion is omitted and the annular metal plate 36 is omitted.
It is also possible to adopt a configuration in which the pipe directly contacts the pipe end face 22.

The core 18 of the illustrated end cap further has a closure 46 that is integral with and extends from the core end extension 27, and if the end cap is attached to the pipe 14, into the pipe 14 such as dust. Can be prevented from entering. Closure body 46 is a thin film material having one or more tear flaps 48 defined by score lines 50. Each flap 48 further includes a plurality of openings 52 through which the openings or cavities in the pipe are suitably vented through the flaps.
Have. In addition, insert your finger into the opening 52 and
The flap 48 can also be torn along. flap
Once the 48 is removed, a suitable end cap removal tool (not shown) is inserted into the pipe to strike the core end extension 54 located between the annular metal plate 36 and the pipe end face 22 and onto the pipe. The end cap 10, which cannot be removed by rotation, can be removed.
In FIGS. 1 to 3, the closing body 46 has the same thickness as the core end extension portion 27 and is an extension body integral with the core end extension portion 27. In FIG. 5, the closure 46 extends further from the inner edge of the core end extension 27. In contrast, in FIG. 6, the closure further extends from the core end extension 27 between the annular metal plate 36 and the sleeve extension 20. The inner surface of the closure 46 is preferably aligned with the outer surface of the annular metal plate 36 and provides guidance when inserting the annular metal plate 36 into the receiving groove of the core end extension 27.

Please refer to FIG. 7 and FIG. Other fastening means are shown for connecting and fastening the sleeve 16 and the core 18 together. This fixing means is provided along the end surface portion of the sleeve end extension portion 20 (that is, the end surface portion of the sleeve end extension portion 20 which is curved from the body of the sleeve 16 and is oriented in a direction perpendicular to the axis of the pipe 14). This is a structure in which a plurality of notches 40 are formed, and a plurality of hook-shaped protrusions (finger-shaped protrusions) 42 are provided in the core end extension portion 27 so as to be engaged in the notches 40. The hook-shaped projecting piece 42 has a rib 44 having an inclined surface (taper) formed at its tip. A protrusion having a rib 44
42 engages in notch 40 to allow sleeve end extension
Ribs 44 engage the notches 40 on the outer surface of 20 to engage the notches 40, thereby causing sleeve 16 to engage.
And the core 18 are connected and fixed to each other.

FIG. 9 shows an example of other fixing means for connecting and fixing the sleeve 16 and the core 18. Multiple keyways 41 on sleeve 16
And a plurality of spline ridges 43 are formed on the core 18, and this structure enables the core to be guided and inserted into the sleeve of the end cap, and the ridges 43 are inserted by the insertion. The keyway 41 can be aligned and entered.

Although the present invention has been described in detail based on particularly preferred embodiments, it will be understood that variations and modifications can be made within the spirit and scope of the invention as described. For example, instead of the cylindrical sleeve 16, the sleeve may be tapered or the sleeve may be frustoconical. Upon its deformation, the outer peripheral surface 26 of the core 18 can be tapered or frustoconical to match the inner peripheral surface 30 of the sleeve. Further, the core 18 can be configured without providing the closing body 46 or without providing the tear flap 48.

EFFECTS OF THE INVENTION The advantages of the present invention are as follows.

Each extension of the sleeve end and the resin core end,
An annular metal plate is inserted between the end surface of the pipe and the wall thickness of the core end extension portion existing between the annular metal plate and the sleeve end extension portion. The impact force applied to the end of the pipe can be effectively absorbed by setting the appropriate size in consideration of the magnitude of the impact force. That is, according to this structure, even if an impact force acts on the end of the pipe in the axial direction of the pipe, the resin core end extension is compressed between the sleeve end extension and the annular metal plate to be deformed. However, the impact force is absorbed thereby, and it is difficult to transmit a large impact energy to the end portion of the pipe.

In the annular metal plate, the entire thickness portion of the end extension portion of the resin core located between the annular metal plate and the sleeve end extension portion or a portion corresponding to a part of the total thickness is the end portion of the pipe. Avoid being cut off by.

If a part of the resin core end extension is present between the annular metal plate and the pipe end face, the annular metal plate is effectively held by the resin core. It is clear that the annular metal plate can be held even if there is no thick portion.

The annular metal plate can be configured so that a large volume portion of the resin core can be subjected to compressive deformation due to impact force by appropriately setting the radial dimension of the annular metal plate according to the purpose of use. It is possible to efficiently disperse the impact force, and it is possible to absorb a large impact energy in the resin core as a buffer.

By using the pipe protecting end cap of the present invention, it is possible to effectively prevent damage to the pipe end where the thread is formed, and to reduce the complexity of performing the work of restoring the damaged pipe end screw. It can be avoided.

According to the pipe protecting end cap of the present invention, a single type of common sleeve is used for various inner cores having different inner thread shapes, and it corresponds to commercially available pipes having various outer thread shapes. It is possible to use a combination of an inner core having a conforming inner screw shape and a common sleeve, and it is possible to reduce the cost by using common parts.

[Brief description of drawings]

FIG. 1 is a partial perspective view showing an example of a pipe protecting end cap attached to an external thread on a pipe end,
Except for the structure of the outer end of the end cap (right end in the figure), it is presented as an embodiment of the present invention. FIG. 2 is a partially enlarged cross-sectional view taken along the line 2-2 of FIG. FIG. 3 is a partial cross-sectional view of another example of a pipe protecting end cap similar to FIG. 2, the end cap being attachable to other types of external threads. FIG. 4 is a partial cross-sectional view similar to FIGS. 1 and 2 of a slightly modified pipe protecting end cap attached to yet another form of external thread. FIG. 5 is a partial cross-sectional view of another example of the pipe protecting end cap. FIG. 6 is a partial sectional view similar to FIG. 5, of a protective end cap for a pipe as an example of the present invention. FIG. 7 is a partial cross-sectional view of a pipe protecting end cap showing another method of externally securing an inner core to a sleeve. 8 is a partial end view of the end cap of FIG. FIG. 9 is a partial cross-sectional view of the end cap showing the spline connection structure between the inner core and the outer sleeve. 10 …… End cap, 12 …… Outer screw, 14 …… Pipe, 16
...... Sleeve, 18 ...... Core, 20 ...... Sleeve end extension, 22 ...... Pipe end surface, 23 ...... Metal ring, 24 ...... Internal thread, 26 ...... Outer peripheral surface, 27 ...... Core end extension Part (first part), 28 ... Outer end of core, 29 ... Inner end edge, 30 ...
… Inner peripheral surface, 31 …… tapered edge, 32 …… opening, 33 …… sleeve end, 34 …… projection, 36 …… annular metal plate, 40 …… notch, 41 …… key groove, 42… … Protrusions, 43 …… Spline ridges, 44 …… Ribs, 46 …… Closing bodies, 48 …… Tear flaps, 50 …… Notching lines, 52 …… Openings, 54 …… Core end extension (second) part).

Claims (8)

[Claims] 1. A pipe protecting end cap (10) for protecting an external thread formed at an end of a pipe (14), the cap (10) being insertable into the sleeve (16). A resin tubular core (18) provided with a screw means (24) capable of being screwed into an external thread (12) at the end of the pipe on its inner peripheral surface; Fixing means (32, 34; 40, 42) for connecting and fixing each other to form an end cap for protecting the pipe, and an outer side in the axial direction of the pipe with respect to the end face of the pipe with the end cap attached to the pipe. And an annular metal plate (36) that covers the end face of the pipe, and the end of the sleeve and the end of the core respectively have extension portions (20, 28) that cover the end face of the pipe from outside in the axial direction of the pipe. With the end cap attached to the pipe, the pipe shaft The sleeve end extension portion (20) is located further outside the annular metal plate in the direction, and the core end portion is sandwiched between the annular metal plate and the sleeve end extension portion. There is a portion (27) corresponding to the full thickness portion or a part of the total thickness of the extension portion, and when an impact force is applied to the end of the pipe, the impact is caused by the deformation of the sandwiched thickness portion 27). A pipe protection end cap in which the thickness dimension of the sandwiched thickness portion (27) is set to a size that absorbs force. 2. The sleeve has an opening (32) in its peripheral wall, and the core has a protrusion (34) in its peripheral wall, and the protrusion is positioned in the opening, so that the fixing means is provided. A pipe protecting end cap as claimed in claim 1. 3. The pipe protecting end cap according to claim 1, wherein the sleeve (16) is made of metal. 4. A portion (27) sandwiched between the annular metal plate (36) and the sleeve end extension portion corresponds to a portion of the total thickness of the core end extension portion, that is, The first portion, and the remaining thickness portion (5
4) That is, the second portion is present between the pipe end surface and the annular metal plate, and the thickness of the second portion is smaller than the thickness of the first portion. An end cap for protecting a pipe as described in the paragraph. 5. The method according to claim 1 or 2, wherein the annular metal plate is disposed in contact with both the core end extension and the pipe end face, and disposed between the two. End cap for pipe protection. 6. The method according to claim 1, wherein the annular metal plate (36) is positioned in the core end extension portion sandwiched between the pipe end surface and the sleeve end extension portion. The pipe protecting end cap described in item 2. 7. The annular metal plate (36) is positioned in the core end extension portion in a posture along a plane substantially perpendicular to the axis of the pipe. Alternatively, the pipe protection end cap described in item 2. 8. The core end extension has an integral closure (46) for closing the core, and the generally closure has a tear flap (48) for providing a port through which it can pass. An end cap for protecting a pipe according to claim 1 or 2.