US2631113A - Method of and apparatus employing an elongated flexible member for cleaning out obstructions from conduits - Google Patents

Description

March 10, 1953 M J v, O'BRIEN 2,631,113

METHOD OF AND APPARATUS EMPLOYING AN ELONGATED FLEXIBLE MEMBER FOR CLEANING OUT DESTRUCTION-S FROM CONDUITS Filed Jan. 13, 1948 Patented Mar. 10', 1953 METHOD OF AND APPARATUS EMPLOYING AN ELONGATED FLEXIBLE MEMBER FOR. CLEANING OUT OBSTRUOTIONS FROM CONDUITS John v. O'Brien, Park Ridge, 111.

Application January 13, 1948, Serial N 0. 2,038

This invention relates to improvements in methods of and apparatus for cleaning out Ohstructions from conduits, of which sewers, drains, pipes and the like are examples, and it consists of the matters hereinafter described and more particularly pointed out in the appended claims. Reference is hereby made to my co-pending application S. N. 2,037, filed on even date herewith, for a method and apparatus of a somewhat similar character.

Cross-reference is also hereby made to my copending application Ser. No. 314,716, filed October 14, 1952, entitled Methods of Cleaning out Obstructions from Conduits, which relates to somewhat similar subject matter.

Heretofore, certain apparatus for this purpose comprised simply a closely wound helical coil having a working or tool carrying end for engagement with the obstruction in the conduit to be cleaned. It has been customary to associate therewith some means for turning the coil axially as it is fed through the conduit in the use of the apparatus. In such use, when the work end of the coil engages the obstruction and is held against rotation thereby, continued turning of the remainder of the coil builds up torque, the magnitude of which is dependent upon the poweremployed to turn the coil and the resistance to turning which the obstruction supplies. When the torque developed is excessive with respect to the particular coil, the elastic limit of the wire in the coils is exceeded and result either in kinking, breaking, or otherwise damaging the coil.

When torque is applied to the coil in a conduit and it is torsioned because of the engagement of the working end with the obstruction, it is the practice momentarily to retract the coil to loosen the tool or work end in or free it from the obstruction so that the torque causes the working end to rotate rapidly wit great force against the obstruction. The tool then cuts through the obstruction or hooks onto the obstruction so that the material causing the obstruction may be withdrawn with the withdrawal of the coil from the conduit, if its character so permits.

To obtain adequate stiffness in such coils the prior practice has been to close-wind the coil under tension to such small diameter as to leave a passageway therethrough no larger than the diameter of the wire of which the coil is composed. In another prior art construction the coil is wound to a larger diameter and provided with a core upon which the convolutions of the coil are impacted, to afford a firm and permanent grip thereon.

8 Claims. (01. 134--8) Neither of these practices is entirely satisfactory for reasons which will be stated later.

Coils for cleaning purposes of this kind are preferably made of a relatively hard steel wire, termed music wire, having a .85 to .95 degree carbon content. They are produced either by winding the wire upon an arbor in a lathe or winding the wire in a coiling machine in which thie' wire is fed with a pushing action against a set of coilin points or dies, to form the wire into a coil which leaves the machine in a direction at substantially a right angle to the line of the feed of the wire.

The wire mentioned, which comes in long lengths, is not always uniform in hardness throughout its length, so that certain portions thereof may be softer than others. Therefore, different portions of the Wire act differently in coiling operations.

I from that before coiling. Such crowding of the metal on the inside of the convolutions produces fissures and cracks in the coil which reduces the capacity of the coil to withstand the torque imposed upon it in use. Therefore, such coils kink -or break more easily than would otherwise be the case. Thus, while coil of smaller diameter afford considerable longitudinal stifi'ness and have lateral flexibility, they tend to kink and break prematurely in use and therefore are not wholly satisfactory.

In order to overcome the disadvantages of the smaller diameter coils, attempts have been made to increase the diameter to the extent necessary to avoid such crowding of the metal. However, when increasing the diameter of the coil,

formed of a given size wire, the capacity of the coil to transmit the torque necessary to do the work required is reduced. Thus, such coils, when subjected to the torque necessary to remove certain obstructions, will collapse, particularly in those convolutions in which the softer metal is present, thus rendering the coil useless for further work.

Attempts have been made to cure or prevent coils of larger diameter from collapsing by employing a central wire or core-around whichthe wire of the coil is so tightly wound that relative longitudinal movement cannot occur between the coil and the embraced core. In use, such coils must be able readily to follow around elbows and other bends in a conduit and in such manner that no permanent bend or kink will be formed in the coil. However, when a coil, having a core so fixed therein that relative longitudinal movement cannot take place between the coil and its core, passes around a bend in a conduit the action results in stretching that part of the core which is on the outside of the bend. As this stretched.

part of the core cannot return to its normalcondition, a permanent kink or bow. is developed in the coil, which cannot be straightened out or re-- .quite flexible, have little longitudinal stifiness .and do not have adequate resistance to torque action. Hence, they tend to collapse prematurely under torque action and when withdrawn from .a conduit, they open up between convolutions and cannot be restored to their original condition. To prevent such coils from opening up when withdrawing the same from a conduit, they have in some instances been provided with a central flexible, but inextensible member of small diameter. The function of this member is merely to. take the pull from the coil. when withdrawing. thecoil, from. a conduit to prevent opening of the convolutions thereof, and it is so small in diameter relative to the. diameter of the coil that. it does not, atv any time, afford internal support for the coil.

One of the objects of the present. invention is to provide apparatus of this kind which includes as a part thereof an elongated coil having the characteristics of a flexible shaft that may be projected work-end first through the bends, elbows and the like of a conduit up to the obstruction therein. Another part of the apparatus is an elongated flexible core that may be inserted into and longitudinally of the coil from its other end toward the work end. The coil and the core are of such diametric cross sectional relation that the core will internally support the coil', to better withstand the torsion developed when turning the coil, with one end engaged with the obstruction, without kinking,

breaking or taking on a permanent set.

Also, it is an object of the invention to provide apparatus of the kind above mentioned wherein the core is: in no manner attached to the coil but may be withdrawn from the coil for cleaning when necessary and may be reinserted thereinto .and is then capable of a longitudinal slipping action within the coil when the latter is not in torsion and which is gripped by the coil for the internal support thereof when in torsion of a magnitude less than that exceeding the elastic limit of the wire of the coil.

The above mentioned objects of the invention,

together with others, along with the advantages thereof, will more fully appear as the specification proceeds.

In the drawing: Fig. l'is a longitudinal sectional view through the work end of a length. of a coil torming a 4 part of the invention, substantially on a full size scale.

Fig. 2 is a view in side elevation showing the preferred form of flexible core employed with and on a scale greater than that of the coil in Fig. 1.

Fig; 3 is a longitudinal sectional view through the other end of the coil (opposite the end appearing in Fig. l) and illustrates the manner in which one end of the core is inserted into the passageway of the coil for a threading therethrough up to'the work end of the coil appearing in. Fig. 1.

Fig. 4 is a transverse sectional view on the line 4-4 of Fig. 3 but on an enlarged scale, through a part of the coil with the core therein and more clearly shows the annular space between the external surface of the core and the internal surface; of the coil when the latter is free of torque.

Fig. 5 is a longitudinal sectional view through a part of an obstructed conduit such as a drain and shows the coil of the apparatus disposed in the conduit with its work end engaged with the obstruction therein and with the core ready for insertion into the other end of thecoil, outside of said conduit and upon which other end is shown a tool, for turning the coil and core jointly about their axes in the further part of the operation of removing said obstruction.

In general, the improved apparatus includes a. closely wound helical coil of desired length and a. flexible core that is insertable into and is withdrawable from the longitudinal bore or passageway of the coil when the coil is in an untorsioned condition. The diameter of the core with reference to that of the bore is such that when said core is disposed within the passageway, a slight clearance onthe order of DOS/.007 is present therebetween. The coil is provided with a work end which is the end first entered into and worked along aconduit until it reaches the obstruction therein. The core, which is in no manner attached to the coil, is disposed entirely outside the coil. until the latter has. been worked into the conduit and after which the core is then inserted into that end of the coil opposite its work end. and which is then disposed outside of the conduit.

After the coil, with the core disposed in its bore, is located in a conduit with its work end engaged with the obstruction therein, the coil is turned axially either by means of a hand tool or a power tool in the proper direction. Assuming the coil. to be wound. with left hand helix, as indicated inthe drawings, the coil will beturned clockwise, as viewed in Fig. 4, and as indicated by the arrow. With the work end engaged with an. obstruction, theaxial turningof the coil in the direction mentioned, builds up torque in the coil, causing a reduction in diameter to the limit aiiorded by the slight clearance space between the core and bore of the coil. The coil is thus caused to engage the core throughout its length and be internally supported and reinforced thereby against-premature opening up, breaking or kinking. However, at

the time the coil was being inserted into the conduit, the core was not disposed therein, and

hence it acted as a relatively free spring readily able to accommodate itself to the tortuous path usually found in conduits from which obstructions, are to. be removed. While the diameter of the coil is being reduced, its length is also being increased, but the space between the core and coil permits the necessary slippage between to 0.95. is known to the trade as a bright music wire, and well serves the purpose.

coil and core. Hence, neither the coil nor the core is stretched or strained, so that both return to normal condition after removal from the conduit, provided of course the apparatus be used within the limits for which it is designed.

Referring now in detail to that embodiment Of the invention illustrated in Figs. 1, 2 and 3 of the drawing, the improved apparatus includes an outer member or envelope in the form of a long coil having an internal bore or passage designed to receive a flexible core II.

The coil 10 is preferably made of a so-called music steel wire having a carbon content of 0.85 Such wire is obtainable in the market,

The wire has such a cross sectional shape that the sides of ad- 'jacent convolutions thereof may roll relatively in the bending of the coil. Preferably, therefore,

and as shown, the wire has a circular cross section.

The coil 10, which is preferably produced by die coiling machines employing adjustable dies or coiling points which determine the outside diameter of the coil, includes a relatively long body 22 having a relatively short tool carrying portion '13 at one end. The diameter of the body portion 12 of the coil is dependent upon the type of work for which the apparatus is to be used. In coils is well adapted for use in the sewer cleaning art,

especially for the smaller size conduits. The outside diameter of the body l2 of the coil is dependent upon the diameter of the Wire to be used therefor, the outside diameter of the core H to be used therewith. and the amount of clearance between the coil and core. For a core having an outside diameter of .217 /.219 and using a wire of .138" for the coil, such wire is tension wound to such an outside diameter as to afford an overall clearance of .005/.007" between the core and the body of the coil. Such a. coil body will have an outside diameter approximating one-half of an inch. Assuming the core to be centrally disposed within the coil, there would then be an annular space of 0025/0035" between the outside surface of the core and the inside surface or bore of the coil.

As shown, the portion !3 0f the coil has an inside diameter of about 0.60 inch for one-half its length and gradually decreases in diameter for the other half of its length, to meet the associated end of the body 12 of the coil. In said portion 53 of the coil, the convolutions are closely coiled or wound, but preferably are not in tension, being heated t a straw color to accomplish this result. Thus, this portion, which is the leading end of the coil, has more flexibility for bending laterally of the axes of the coil and is thus better adapted for passage through a conduit having short bends, curves, joints. etc.

The free open end of said portion 13, as shown, has threaded thereinto a plug M, which serves to support an obstruction removing tool and which, in this instance, includes a pair of curved cutting arms. Other forms of tools and work ends may be provided, the form illustrated in the drawing being merely one well adapted for the use intended.

The core H is preferably in the form of a flexible member,*such as used for the core part in the drives for speed-ometer and dental engines.

-A core which has been found satisfactory comprises a central wire Ha and a plurality of multiple spring wire strand layers lib with the strands in each layer wound in opposite directions. Material of this kind, which is best illustrated in Fig. 2 and known as speedometer core may be obtained in the open market in various diameters and no claim is herein made to such material, per se. Preferably the ends of the core are ground to afford a tip or point lic (see Fig. 3) at each end and the same may be spot brazed to prevent fraying. Such a tip or point acts as a lead to make easier the threading or working of the core into the coil.

It will be understood, of course, that the number of layers and the numbers of strands in each layer and the sizes of wire will vary for different or specific sizes. However, it is believed that a general description of certain sizes of cores will be helpful. Hence, the wire requirements for three examples or sizes, known as 220 speedometer core, 187 speedometer core and speedometer core will be given.

La ea yer No. Angle, Wne Dla.

Degrees l .013 Steel Shaft Wire. 4 39 .013 Steel Shaft Wire. 4. 19 .013 Steel Shaft Wire. 4 14 .015 Steel Shaft Wire. 4 11 .017 Steel Shaft Wire.

.l25/.1'27 lbs. per/M Feet 32 .13

g Internal Friction Deflection Factor:

Windup Unwind 104 187 speedometer core Helix Layer No Egg Wire Dia.

Degrees Center l .017 Steel Shaft Wire. 1; 4 37 .015 Steel Shaft Wire. 4 18 .015 Steel Shaft Wire. 4 13 .017 Steel Shaft Wire. 4 10 .017 Steel Shaft Wire. 4 10 .022 Steel Shaft Wire.

Actual 0. D. 186/ 188 Weight "lbs. er lltFlTe t Internal Friction -21-! Deflection Factor:

Windup 15 Unwind 31 Wire requirements, 220 speedometer core Helix Layer No 12 5 Wire Die.

Degrees l .017 Steel Shaft Wire. 4 37 .015 Steel Shaft Wire. 4 18 .015 Steel Shaft Wire. 4 14 .017 Steel Shaft Wire. 4 13 .024 Steel Shaft Wire. 4 13 .033 Steel Shaft Wire.

Actual O. D. .21 Weight 7/ 2] 9 Internal Friction Deflection Factor:

Win-dun Unwind the core H and using a .138 diameter wire for the coil body, the coil body wire is wound to provide an overall clearance of .oos"/.0o7" between the outside of the core and the bore of the coil. Assuming the core to be disposed centrally in the bore, there will be a clearance space of between .0025/.0035" between each side of the core and the associated side of the bore. This clearance space is best shown and indica ed in Fig. 4 by the numeral 55. The body 12 of such a coil will have an outside diameter of approxlmately .5".

Examples of other more commonly used cores and coils will be given for illustrative purposes. Using 187 speedometer core (Example 2) having an outside diameter of .l8d"/.188" for the core I! and using .120 diameter wire for the coil body, the coil body wire is wound to provide an overall clearance of .005" /.00'7 between the outside of the core and the bore of the coil. Assuming the core is isposed centrally in the bore there will be a clearance space of between .0025"/.G035" between each side of the core and the associated side of the bore. Such a body (2 will have an outside diameter of about .433".

Using 130 speedometer core (Euample 3) having an outside diameter of .l25"/.127 for the core H and using .80 diameter wire for the coil body, the coil body wire is wound to provide an overall clearance of .005"/.(l9'7" between the outside of the core and the bore of the coil. Assuming the core to be disposed centrally in the bore, there will be a clearance space of between .G025/.0035" between each, side of the core and the associated side of the bore. Such abody i2 will have an outside diameter of about .292.

Thus, it is assured that the core, though not permanently carried by the coil, may be readily worked through the coil when disposed in a tortuous path as is sometimes presented by a conduit. Therefore, the core and the coil are each in their most freely flexible condition readily to follow the necessary path when workin the coil into a conduit and when working the core into the coil without producing a kink or permanent change of form or either one thereof.

When the coil with the core so disposed therein is positioned in a conduit, as soon as suilicient torque is imposed upon the coil, it constricts itself to engage the core so the core afiords an internal support for the coil against the action of torque tending to fracture the coil or produce kinks or breaks therein.

In the use of the apparatus, when the core is disposed in the coil, a tool, either hand-operated or motor-operated, is used for turning the coil axially and this in the direction of the arrow in Fig. 4. These tools are or may be conventional and are well known in the art. I have illustrated a motor operated tool it having a chuck 58 to grip and turn the coil. After the work or tool end of the coil has engaged an obstruction, for example it in Fig. 5, in a conduit 28 and the turning action is continued in the proper direction, torque is built up in the coil and this causes the coil to constrict itself in diameter and engage the core as before explained.

From the above it will be obvious that in using the apparatus disclosed herein, the coil functions substantially as a free flexible spring shaft which will readily slide around bends and elbows and past joints in a conduit thereby greatly facilitating insertion of the coil into the conduit. After the. core is disposed in the coil, when the work end engages the obstruction, and turning movement is imparted to the coil in the manner indicated, from a point outside the conduit, this will cause a reduction in the size of. the coil. so as to thereby engage the core, the core acting to provide internal support for the coil. Tests show greatly improved power transmitting capacity without injury to the coil- It will also be understood that the core extends substantially throughout the entire length of the coils when disposed therein. Hence, relative longitudinal movement between thecoil and core can readily take place as the coil is reduced in diameter and increased in length in the preliminary stages of removing an obstruction from a conduit.

Several examples of coil sizes, cores, space be tween core and coil and wire requirements, etc. have been given. While these have been found satisfactory in actual use, it should be understood they have been given as by way of illustration and not necessarily by way of limitation, except where the functioning requires such limitation. For example, the annular space between the core and bore of the coil has been given as of the order of .005"/.007" but this may vary, depending upon the size and characteristics of the wire of which the coil is formed. The purpose of the space between the coil and core is to permit the coil initially to function as a substantially free coil with relative slippage between coil and core and then when the coil is subjected to torque, which elongates it and reduces its diameter, to be supported internally by the core whereby to increase the power transmission capacity of a given coil whilst maintaining it in good condition. Hence, while the space between core and coil. may be more or less than that given, it should never for any particular core-coil combination be so small that the freedom of the coil in the initial part of an obstruction removing operation is impaired to the extent that will cause damage to the coil or core when the device is used. for its intended purpose and within. the power range for which the device is designed.

Again, the space between the core and. coil should not be too great-otherwise damage to the. coil will be caused before it engages the core and is given internal support thereby. Therefore, the maximum space between the core and coil should be such that it can be taken up by the reduction, under torque action, of the coil diameter before the elastic limit of the particular coll wire is exceeded. Hence, the smallest amount of space between the core and coil, which will afiord free slippage between coil and core. in the initial part of the operation, is generally preferred.

Specification of cores which have been satisfactorily used, have been given, but these too are by way of illustration. For example, wire other than steel may be used where corrosion is an important consideration. The wire of the core should, however, have spring characteristics so that when flexed it will return to normal and not take a permanent kink or set.

Hence, While in describing the invention I have referred in detail to the form, arrangement and construction of and diameters of the parts involved, the same is to be considered only in the illustrative sense and therefore I do not wish to be limited thereto except as may be specifically set forth in the appended claims.

I claim as my invention:

1. The method of removing obstructions from conduits which consists in positioning a helically wound flexible wire coil having a longitudinal passageway therein within a conduit with the work-end of the coil adjacent the obstruction to be-removed therefrom, providing a core member of less cross sectional diameter than that of said passageway, and disposing the same in said passageway from that end of the coil opposite said work end after said coil has been positioned in said conduit, and causing the work end of the coil to engage said obstruction while turning the coil axially from a point spaced from said work end and in a direction to build up torque in the coil sufficient .to reduce its diameter and cause it to engage and be internally supported by said core.

2. The method of removing obstructions from conduits" which consists in positioning a helically wound flexible wire coil having a longitudinal passageway therein within a'conduit with the work end of the coil adjacent the obstruction to be removed therefrom, providing a core member of less cross sectional diameter than that of said passageway, inserting one end of said core into that end of said passageway opposite the work end of said coil and feeding the core longitudinally along the passageway ;until said end of said core is disposed in operative position relative to said work end of the coil, causing the work end of the coil to engage said obstruction while turning the coil axially from a point spaced from said work end and in a direction to build up a torque in the coil sufiicient to reduce its diameter and cause it to engage and be internally supported by said core, before the elastic limit of the wire of the coil is reached so that said coil and core coact in the further operation of removing the obstruction from the conduit.

3. A device for removing obstructions from conduits and embodying therein, in combination with a helically wound flexible wire coil having a work end and a longitudinal passageway therein, adapted to be inserted work end first into a conduit so that said work end is disposed adjacent the said obstruction in said conduit, a flexible core member having a cross sectional diameter of such lesser size than that of said passageway as to provide a limited clearance space between coil and core, insertable at any time while the coil is torsionally unstressed end first into said passageway from that end of the coil opposite the work end thereof and workable through said passageway of the coil while the latter is disposed in position in said conduit, until said end of the core is in operative relation to said work end of the coil, the dimensional characteristics of said coil and core being such that when the core is disposed in position in said coil and said coil is held at its work end by said obstruction and is turned axially from a point spaced from the work end and in a direction to build up torque therein, said coil will reduce in diameter to such an extent that it will engage and be internally supported by the core before the elastic limit of the wire of the coil is exceeded.

4. A device for removing obstructions from conduits and embodying therein, in combination with a helically wound flexible wire coil having a work end and a longitudinal passageway therein, adapted to be inserted work'end first into a conduit so that said work end is disposed adjacent the said obstruction in said conduit, a flexible core member comprising a center wire and a plurality of layers of multiple wire strands wound therein and which core has a cross sectional diameter of such lesser size than that of said passageway as to provide a limited clearance space between coil and core and insertableat any time while the coil is torsionally unstressed end first into said passageway from that end of the coil opposite the work end thereof and workable through said passageway while the latter is disposed in position in said conduit, until said end of the core is in operative position relative to the work end of the coil, the dimensional characteristics of said coil and core being such that when the core is disposed in position in said coil and said coil is held at its work end by said obstruction and is turned axially from a point spaced from the work end and in a direction to build up torque therein, said coil will reduce in diameter to such an extent that it will engage and be internally supported by the core before the elastic limit of the wire of the coil is exceeded.

5. A device for removing obstructions from conduits and embodying therein, in combination with a helically wound flexible wire coil having a work end and a longitudinal passageway therein, adapted to be inserted work end first into a conduit so that said work end is disposed adjacent the said obstruction in said conduit, a flexible core member comprising a center wire and a plurality of layers ofmultiple wire strands wound therein and which core has a cross sectional diameter less than that oftsaid passageway, providing a clearance of DOE/.007 between the coil and core, said core being insertable at any time while the coil is torsionally unstressed end first into said passageway from that end of the coil opposite the work end thereof and workable through said passageway while the latter is disposed in position in the conduit until said end of the core is in operative position relative to the work end of the coil, the dimensional characteristics of said clearance being such that when the core is disposed in position in said coil and said coil is held at its work end by said obstruction and is turned axially from a point spaced from said work end and in a direction to build up torque therein, said coil will reduce in diameter to that extent that it will engage and be internally supported by the core before the elastic limit of the wire of the coil is exceeded.

6. Apparatus for removing obstructions from conduits comprising an elongated helical flexible spring wire coil having a longitudinal passageway therein and a dimensionally related core member for conjoint use therewith in an obstruction removing operation, said core member being movable as an entity and embodying a plurality of layers of helically wound strands, the cross sectional dimension of the core being of such lesser size than at least the major part of the passageway in the coil when torsionally unstressed as to provide a limited clearance space between the core and coil when the core is positioned within the coil and entirely throughout the length of the core within coil, aid limited clearance space permitting movement of the core longitudinally in both directions while the coil is torsionally unstressed, said clearance space being such that when the coil is held at one end and turned axially from a point spaced from said end the limited clearance space is taken up by a reduction of coil diameter until the coil engages and is internally supported by the core before the elastic limit of the coil wire is exoeeded.

'7. Apparatus for removing obstructions from conduits comprising an elongated helical flexible spring coil having a longitudinal passageway therein and a dimensionally related core member for conjoint use therewith in an obstruction removing operation, said core member being movable as an entity and embodying a plurality of 'layers of helically wound strands, the cross sectional dimension of the core being of such lesser size than at least the major part of the passageway in the coil when torsionally unstressed as to provide a limited clearance space between the-core'and coil when the core is positioned within the coil and entirely throughout the length of the core within coil, said limited clearance space permitting movement of the core longitudinally in both directions while the coil is torsionally unstressed, the cross sectional size of :the coil wire being at least several times .the cross sectional size of the individual strands of which the-core is :composed, said clearance space being such that when the coil is held .at one end and turned axially from a point spaced from said end the limited clearance space is taken up by areduction of coil diameter until the coil engages and is internally supported by the core before the elastic limit of the coil wire is exceeded.

8. A device for, removing obstructions from conduits comprising a helically wound flexible spring wire coil vhaving a longitudinal passageway therein, said .coil having ends at least one of which is a'work endpa flexible spring wire core disposed within said passageway and of such lesser diameter than that of the passageway as to provide a clearance space between coil and core throughout at least amajor portion thereof when the coil "is torsionally unstressed, which clearance space is of such limited size that it can be taken up by torsional reduction of cell diameter before exceeding the elastic "limit of the coil wire, and means at least at one end of the coil detached from :but preventing longitudinal movement of'the core as a-whole beyond said one end of the coil, thereby providing vfor the free slidable :relative movement between soil and core when the .coil is 'ltorsionally unstressed whereby when the coil .is held against turning movement at the work end and :is turned :axially .from :a point spaced from said end, and in a direction to :build up :sufiicientitorsional stress, the diameter of the coil will he reduced, thereby taking :up the limited clearance between coil and core and causing the coil to be :internally supported by the core in such reduced portion of the coil.

JOHN V. OBRIEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name :Date

887,160 Webb May 12, 1908 1,154,369 Browning Sept. 21, 1915 1,600,373 Stremel Sept. .21, 1926 2,006,333 Angeli :et a1. July 2, 1935 2,244,735 Silverma-n June 10, 1941 2,336,334 Zublin .Dec. 1'1, 1943

Claims (2)

1. THE METHOD OF REMOVING OBSTRUCTIONS FROM CONDUITS WHICH CONSISTS IN POSITIONING A HELICALLY PASSAGEWAY THEREIN WITHIN A CONDUIT WITH THE WORK END OF THE COIL ADJACENT THE OBSTRUCTION TO BE REMOVED THEREFROM, PROVIDING A CORE MEMBER OF LESS CROSS SECTIONAL DIAMETER THAN THAT OF SAID PASSAGEWAY, AND DISPOSING THE SAME IN SAID PASSAGEWAY FROM THAT END OF THE COIL OPPOSITE SAID WORK END AFTER SAID COIL HAS BEEN POSITIONED IN SAID CONDUIT, AND CAUSING THE WORK END OF THE COIL TO ENGAGE SAID OBSTRUCTION WHILE TURNING THE COIL AXIALLY FROM A POINT SPACED FROM SAID WORK END AND IN A DIRECTION TO BUILD UP TORQUE IN THE COIL SUFFICIENT TO REDUCE ITS DIAMETER AND CAUSE IT TO ENGAGE AND BE INTERNALLY SUPPORTED BY SAID CORE.

3. A DEVICE FOR REMOVING OBSTRUCTION FROM CONDUITS AND EMBODYING THEREIN, IN COMBINATION WITH A HELICALLY WOUND FLEXIBLE WIRE COIL HAVING A WORK END AND A LONGITUDINAL PASSAGEWAY THEREIN, ADAPTED TO BE INSERTED WORK END FIRST INTO A CONDUIT SO THAT SAID WORK END IS DISPOSED ADJACENT THE SAID OBSTRUCTIOIN IN SAID CONDUIT, A FLEXIBLE CORE MEMBER HAVING A CROSS SECTIONAL DIAMETER OF SUCH LESSER SIZE THAN THAT OF SAID PASSAGEWAY AS TO PROVIDE A LIMITED CLEARANCE SPACE BETWEEN COIL AND CORE, INSERTABLE AT ANY TIME WHILE THE COIL IS TORSIONALLY UNSTRESSED END FIRST INTO SAID PASSAGEWAY FROM THAT END OF THE COIL OPPOSITE THE WORK END THEREOF AND WORKABLE THROUGHT SAID PASSAGEWAY OF THE COIL WHILE THE LATTER IS DISPOSE IN POSITION IN SAID CONDUIT, UNTIL SAID END OF THE CORE IS IN OPERATIVE RELATION TO SAID WORK END OF THE COIL, THE DIMENSIONAL CHARACTERISTICS OF SAID COIL AND CORE BEING SUCH THAT WHEN THE CORE IS DISPOSED IN POSITION IN SAID COIL AND SAID COIL IS HELD AT ITS WORK END BY SAID OBSTRUCTION AND IS TURNED AXIALLY FORM A POINT SPACED FROM THE WORK END AND IN A DIRECTION TO BUILD UP TORQUE THEREIN, SAID COIL WILL REDUCE IN DIAMETER TO SUCH AN EXTENT THAT IT WILL ENGAGE AND BE INTERNALLY SUPPORTED BY THE CORE BEFORE THE ELASTIC LIMIT OF THE WIRE OF THE COIL IS EXCEEDED.

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