US3264907A

US3264907A - Perforator with slug retaining features

Info

Publication number: US3264907A
Application number: US405427A
Authority: US
Inventors: Frank H Mueller; Jr Wilbur R Leopold; Carl E Floren; Lynn D Edwards
Original assignee: Mueller Co
Current assignee: Mueller Co
Priority date: 1964-10-21
Filing date: 1964-10-21
Publication date: 1966-08-09
Anticipated expiration: 1983-08-09

Description

Aug. 9, 1966 F. H. MUELLER ETAL 3,264,907

PERFORATOR WITH SLUG RETAINING FEATURES Filed Oct. 21, 1964 2 Sheets-Sheet 1 VII/I ATTORNEYS United States Patent O 3,264,907 PERFRATR Wl'ilrl SLUG RETAINING FEATURES Frank H. Mueller, Wilbur R. Leopold, Jr., Carl E. Floren, and Lynn D. Edwards, Decatur, lll., assignors to Mueller Co., Decatur, lll., a corporation of Illinois Filed Oct. 21, 1964, Ser. No. 405,427 8 Claims. (Cl. 77-38) The present invention relates to an improvement in a tool for perforating the wall o-f a pipe such as a main or the like and, more particularly, to an improvement in a tool for cutting a slug or coupon from the wall of a main `and retaining the coupon therein so that the ycoupon does not drop down into the main.

It it oftentimes desirable in gas distribution or other systems to tap into a service main of a ductile metal or plastic in order that service pipes or lines may be operatively connected to the main. Drilling machine and closure valve assemblies have been used for this'` purpose, mounted on Ts attached to the main providing for the drilling of a hole in the main through the valve and then using the valve as a permanent closure after the drill is wllthdtrawn. Cheaper' and more simple arrangements were later provided, wherein the valve is omitted and the cutting member or perfo-rator is left in place in the T and serves as a valve to close the opening which has been cut, as shown in Patent No. 2,839,075, issued to Frank H. Mueller, June 17, 1958.

An object of the present invention is to provide an improved pertforating tool for cutting a main, the tool requiring less torque to operate during the cutting of the coupon from the wall of the main, and being of the type which positively retains the coupon during the cutting operation so that when the tool is removed from the tapped hole in the main, the coupon is also removed completely out of the main.

Another obje-ct of the present invention is to provide an improved cutting tool hav-ing a forwardly facing cutting surface and a minimum of frontal end area, with a reduced side contacting surface so that there is less drag on the tool when rotary motion is applied to the tool during cutting.

These and other objects of the present invention will appear more fully in the following speciiication, claims, and drawings, in which:

FIGURE 1 is a vertical sectional View through a main and a service T and also illustrating partially in vertical section and partially in elevation the improved cutting tool of the present invention in a position after a hole has been tapped in a main;

FIGURE 2 is an enlarged fragmentary side elevational view of the cutting tool of the present invention;

FIGURE 3 is a view similar to FIGURE 2 but with the tool of FIGURE 2 rotated 90 on its axis in a counterclockwise direction looking from the top of FIGURE 2;

FIGURE 4 is a view similar to FIGURES 2 and 3, the cutting tool being rotated 180 with respect to FIGURE 2 and 90 with respect to FIGURE 3;

FIGURE 5 is a bottom plan view of the cutting end portion of the tool of the present invention taken substantially on the line 5-5 of FIGURE 4, the view being enlarged over the view of FIGURE 4;

FIGURE 6 is a view ot the cutting tool similar to FIG- URE 3 but having a portion of the tool broken away adjacent the cutting end of the saune to thereby illustrate the coupon retaining threads in the closed bottom bore of the cutting end;

FIGURE 7 is a layout of the cutting end portion of the tool and illustrating the various surfaces of the forward facing cutting edge; and

FIGURE 8 is a fragmentary sectional view of the main dld'i Patented August 9, 1966 ,and conventional serv-ice T, the view illustrating the cutting tool in elevation and having cut a coupon from the main, the coupon being retained in the tool.

Reterring now to FIGURE 1 there is disclosed a main .10 for a duid pressure distribution system such as a gas system or the like, `a m-ain hole 12 having been tapped in the wall of the main by the removal of a slug or coupon 14. Main 10 may be made of the usual materials such as steel, plastic, or any suitable metal. A T 116 is illustrated secured to the main l0, this particular T being made of rnet-al and welded to the main 10 when the main is made of metal. The T titting 16 is of the type disclosed in United States Patent No. 2,839,075, issued June 17, 1958, to Frank H. Mueller. It has a body portion 17 with an interiorly threaded through bore 18 and a lateral outlet opening 20 communicating with a bore 22 in a branch 24. The upper end of the main body portion 17 is exteriorly threaded as indicated at 26 in order that it can receive an interiorly threaded service cap 28.

The cutting tool of the present invention is generally designated at 30 and is provided with a plug-like body member 32 having a irst body portion 34 which is eX- teriorly threaded at 36 with threads that may be received in the interiorly threaded bore E18. The first body por-,tion 34 has an end provided with a non-circular socket or recess 38 therein for receiving an Allen wrench or the like. It will now be appreciated that rotation of an Allen wrench in the socket 38 will cause the tool 30 to advance or retract in the threaded bore 18, depending on the direction of rotation. The body member 32 has a second body portion 40 at the opposite end thereof, the second body portion 40 having a diameter on any plane therethrough normal to the axis of the body member 30 which is less than the diameter of the first body portion 34. A more detailed description of the second body portion 40 will follow later in the specication.

Intermediate the first body portion 3l and the second body portion 40 is a cylindrical intermediate body portion 42, the intermediate body portion 42 having a diameter less than the diameter of the lirst body portion 34 and greater than any of the diameters of the body portion 40. The intermediate body portion 42 is connected to the second body portion 40 by a conical shoulder 4t, the purpose of which will be described later in the speciiication.

The end of the second body portion 40 is provided with ta bore t6 for a purpose well known in the art, this bore having interior threads t8 (FIGURE 6) to retain the cut coupon. The interior threads t8 have a relatively flat or plane root 50 between adjacent threads thereby providing for easier reception of the coupon, the threads 48 receiving Iand retaining the coupon 14 as the same is being cut by the cutting tool 30.

The second body portion 40 comprises Ia shank portion 52 and a cutting end portion S4 separated from the shank portion by a short cylindrical portion 56. The shank portion 52 has a back taper which is shown exaggerated in the drawings at T, the taper T being in the order of three-fourths of van inch per foot. The cutting end portion 54 has a forward taper T. The cylindrical portion 56 between the back tapered shank portion 40 and the forward tapered cutting end portion 54 is in the order of three sixty-fourths of an inch so that there is a minimum of side area contact between the second body portion 40 land the wall of the hole 12 being cut.

As best shown in FIGURES 2 through 7, inclusive, the cutting end portion 54 of the cutting tool 30 is provided with a forwardly facing ilat cutting surface 60, defined by a pair of spirally milled flat slopes 62 `and 64 intersecting in a cutting point 66. The

slopes

62 and 64 terminate at their low side in an arcuate flat portion 68 lying in a plane normal to the axis of the body member 30. The slope 62, which is `the forward slope whenthe tool is being threaded downwardly in the through bore 18 to cut the coupon 14, is of a greater angle A with respect to a plane normal to the axis of the cutting tool than is the angle B of the trailing slope 64 and, thus, as shown in FIGURE 7, the length of the trailing slope is greater than the length of the forward slope 62. By having the forward slope 62 at a greater angle than the trailing slope 64 and by having only a single cutting point 66 coupled with the taper T on the cutting end portion, the frontal area of the cutting tool 30 which is performing the cutting action for cutting the coupon 14 from the main 10 is minimized. This reduces `the frictional contact and permits the coupon t be cut more cleanly and without -any significant amount of head being formed thereon which would interfere with the removal of the coupon. The torque required t-o rotate the cutting tool 30 and cause the cutting action is further reduced as mentioned above by providing the relatively minimum amount of surface contact between the wall of the hole 14 being cut and the second body portion of the tool member 32 because of the back taper T provided on the shank portion 40. The surfaces 62 and 63 each occupy about 90 of the circular end area of the cutter, while the surface 64 -occupies about 180 of this end area.

To further enhance the operation of the cutting tool 30, an alkyd resin paint having molybdenum disulfide (MOSZ) is coated on at least the second body portion 40 and the threads 48 of the bore 46 to act as a lubricant during the cutting operation. If desired, the threads 36 of the first body portion 32 may also be coated. It has been found desirable to dilute the alkyd resin paint and molybdenum disulfide 60% with a thinner when coating the threads but it has also been found that the cutting portion of the second body member should be coated at full strength or thinned only up to 20%. The molybdenum disulfide (MOS2) used was a commercial product manufactured by Acheson Colloid Co., Port Huron, Michigan, and known as DAG 232. While a binder of alkyd resin paint is preferably used as it will quickly cure at room temperature, other binders for the molybdenum disulfide may be used such fas an epoxy binder.

It will be appreciated by those skilled in the art that the cutting tool 30 must be made of a material which is harder than the material of the main being cut. For example, if the main is steel, the tool 30 is made of a hardened steel which is sand blasted after the hardening operation.

The operation of the cutting tool 30 is substantially similar to the operation described in the aforementioned United States Patent No. 2,839,075. After the T 16 has been suitably secured to the main 10, the perforator tool 1s lubricated and then inserted in the T, and with the cap 2S removed, a wrench is applied to the socket 38 of the tool 30 for rotating the same. tool is then advanced by a threading action until its cutting edge engages the wall of the pipe. Further adnot only cuts the coupon 14 from the main but the coupon is also threaded into the interiorly threaded closed bottom bore 46. Once the coupon 14 has been completely severed from the main 10 and the hole 12 formed therein, the tool is rotated in an opposite direction `to the position shown in FIGURE 1 and the cap is re-applied to further seal the joint. It will, of course, be appreciated that the branch 24 will have been previously connected to a service line which is desired to be tapped into the main. If it is ever de- (which has been left in the T) can then be re-threaded down until it reaches a position where the conic-al surface 44 abuts against the edge of the hole 12 to thus seal off the hole 12.

It will thus be seen that the objects and advantages of this invention have been fully and effectively accomplished. Various changes may be made to the specific having a first body portion adjacent the end with the drive socket, said `first body pozrtion having exterior threads thereon, said body member having a second body portion adjacent the end with the closed body circular ond body portion being of reduced diameter cylindrical.

4. A cutting tool as claimed in claim 1 in which said interior threads of said closed bottom circular bore have a root portion which is fiat.

5. A cutting tool as claimed in claim 1 in which said pair of slopes of different degrees has a forward slope at a greater angle to the body member than the 6. A cutting tool for cutting a coupon from the wall of the main and for .retaining the coupon after the same is cut, said cutting tool comprising: an elongated plug-like body member means at one end thereof and a closed portion, said forward facing cutting edge of said cutting end portion being defined by a pair of spirally arranged at slopes, one being a forward slope and the other being a trailing slope, said pair of slopes joining in a single cutting point and merging into a at arcuateV portion lying in a .plane normal to the axis of the body member, said forward slope having a greater angle with respect to the plane normal to the axis of the body member than said trailing slope, said closed bottom circular bore having interior threads with a flat root portion for receiving the coupon as the same is cut from the wall of the main to thereby retain the same in the cutting tool, and at least the exterior surface of said second body portion and the interior threads of said closed bottom borre being coated with a binder having molybdenum disulfide therein. 7. A cutting tool as claimed in claim 6 in which said binder is an alkyd resin paint.

8. A cutting tool as claimed in claim 6 in which said binder is an epoxy binder.

No references cited.

G. A. DOST, Assistant Examiner.

Claims

1. A CUTTING TOOL FOR TAPPING A HOLE IN A MAIN BY CUTTING A COUPON FROM THE WALL OF THE MAIN AND RETAINING THE COUPON AFTER THE SAME IS CUT, SAID CUTTING TOOL COMPRISING: AN ELONGATED PLUG-LIKE BODY MEMBER HAVING A DRIVING SOCKET AT ONE END THEREOF AND A CLOSED BOTTOM CIRCULAR BORE AT THE OTHER END THEREOF, SAID BODY MEMBER HAVING A FIRST BODY PORTION ADJACENT THE END WITH THE DRIVE SOCKET, SAID FIRST BODY PORTION HAVING EXTERIOR THREADS THEREON, SAID BODY MEMBER HAVING A SECOND BODY PORTION ADJACENT THE END WITH THE CLOSED BODY CIRCULAR BORE, SAID SECOND BODY PORTION BEING OF REDUCED DIAMETER WITH RESPECT TO SAID FIRST BODY PORTION THROUGH ANY PLANE THEREOF NORMAL TO THE AXIS OF THE BODY MEMBER AND HAVING A FORWARD TAPERED CUTTING END PORTION AND A BACK TAPERED SHANK PORTION WHEREBY SAID SECOND BODY PORTION HAS A MAXIMUM DIAMETER IN A PLANE NORMAL TO THE AXIS OF THE BODY MEMBER IN AN AREA BETWEEN THE SHANK PORTION AND THE CUTTING END PORTION THEREOF; SAID CUTTING END PORTION HAVING A FLAT FORWARD FACING CUTTING EDGE DE-