US2974932A - Conduit threader - Google Patents

Description

March 14, 1961 c. P. XENIS CONDUIT THREADER 4 Sheets-Sheet 1 Filed June 26, 1958 22 mlll I N V EN TOR. Co/vsrmv r/NEPXEN/S.

March 14, 1961 c.' P. XENIS 2,974,932

CONDUIT THREADER Filed June 26, 1958 4 Sheets-Sheet 2 mmhwyzkw ATTORNEY-i March 14, 1961 c. P. XENIS CONDUIT THREADER 4 Sheets-Sheet 3 Filed June 26, 1958 March 14, 1961 c. p. XENlS 2,

' CONDUIT THREADER Filed June 26, 1958 4 Sheets-Sheet 4 R! Q Q Q INVENTOR.

CONJTANTINEPX ENIJ:

Mia/MM? United I States Patent O CONDUIT THREADER Constantine P. Xenis, Douglaston, N.Y., assignor to Consolidated Edison Company of New York, Inc., New York, N .Y., a corporation of New York Filed June 26, 1958, Ser. No. 744,860

9 Claims. (Cl. 254-1345) This invention relates to apparatus for traveling through pipes, conduits and the like, and more particularly to apparatus for threading such pipes or conduits.

This invention comprises an improvement over the apparatus shown in my copending US. Patent application Serial No. 581,630, now Patent Number 2,917,762.

In such copending patent application the invention, in one form thereof, is constituted by an apparatus for traveling through pipes and the like which includes in combination a pair of coaxial brush devices each having bristles extending outwardly in circumferential array from a core, oppositely extending of such bristles being adapted to engage concurrently opposite inner surfaces of the pipe while they are tilted in a common direction with respect to the longitudinal axis of the brush device. Such pair of brush devices support therebetween suitable vibratory power means which can vibrate the cores of the brush devices in directions substantially at right angles to the longitudinal axis of the apparatus. Such vibratory power means can comprise, for example, means for moving the cores of the brush devices so that they generate a generally conical surface of revolution thereby to cause the apparatus to advance through the pipe. Alternatively, the vibratory power means can vibrate merely laterally of the longitudinal axis of the apparatus. 'Where a vibratory power device is employed which causes the longitudinal axes of the brushes to move in a path conforming to a conical surface of revolution, this form of motion results in advancing linearly the extremity of each bristle in the conduit by causing its outer extremity to scrape forwardly on the inner wall surface of the pipe in response to such vibratory force which angularly shifts the brush core in such a way that the bristle is so caused to move, an oppositely extending bristle maintaining a foothold on the opposite inner wall surface of the pipe thereby facilitating such advancement. Generally opposed pairs of bristles thus are manipulated successively around the angular extent of a cylindrical brush thereby to cause the apparatus to advance itself through the pipe.

The cores from which the bristles extended in the aforementioned copending patent application have been rigid metal devices in which the bristles are rigidly held.

The improvement embraced by the present invention comprises, in one form thereof, an apparatus such as that above described but wherein each brush core is constituted by a relatively thick sleeve of resilient rubber-like material supported by a central supporting member, such as a metal rod, the bristles being embedded in the sleeve. Because of such resilient sleeve mounting for the bristles, the latter can be and are relatively more stiflf and straight as compared to the bristles of such copending application thereby achieving the advantages set forth below.

The invention in still another form thereof comprises a device as defined above with the exception that the two brush-like devices, instead of having the bristles thereof tilted in a common direction with respect to the longitudinal axis thereof, that is, all of the bristles of both brushes tilted backward with respect to the direction of movement, is constructed wherein the bristle tilt of one of the brushes is in one direction and that of the other brush is in the opposite direction. Means are employed for selectively covering up or housing one or the other of such brushes thereby providing an apparatus which is able to move either forward or backward within a pipe depending upon which of the brushes is covered. The device for covering a brush is, in the form shown, a cylindrical sleeve preferably of hard metal which surrounds the apparatus and is axially movable relative thereto from one end thereof to the other for the purpose of covering the outer extremities of either one of the two brushes. Suitable remote control means are provided for axially shifting such cylindrical sleeve so that it covers either one or the other of the brushes.

One of the objects of the present invention is to provide an apparatus of the above character having a brush construction which will permit the use of the stiffest possible bristles in the brushes, bearing in mind that the brush construction must not fit too tightly in a pipe. Relatively stiff bristles enable the most economical use or best use of the power of the vibratory motor permitting maximum speed at maximum thrust in the pipe, this being attributable to a minimizing or reducing of any bowing of the brush bristles. Excessive bowing of the brush bristles reduces the traction of the device in a pipe and causes a loss of power otherwise devoted to the production of forward thrust.

Thus, another object is to provide a construction of the above character which permits the use of bristles which can tilt or change the attitude thereof as a result merely of being thrust in a pipe and without any appreciable bowing of the bristle, such bristles also not being subject to any appreciable bowing as a result of the actuation of the vibratory power means which is connected thereto and which causes the advance thereof through the conduit.

A further object is to provide a device of the character described having such brushes and bristles wherein there is prevented an excessive bending or bowing of the bristles when the device is pulled backwards through a pipe after being allowed to crawl into the pipe, such bending or bowing tending to cause a permanent set in the metal of the bristles and thus preventing an eflicient crawling action of the device.

A further object is to provide an apparatus of this character having improved traction characteristics.

Another object is to provide an apparatus of this character having improved efficiency in the use of its motor power.

A further object is to provide an apparatus of this character having improved forward thrust and improved speed.

Another object is to provide an apparatus of this character which can be reversed when in a pipe without dam age to the apparatus. A

Various further and more specific objects, features and advantages of the invention will more clearly appear from the detailed description given below taken in connection with the accompanying drawings which form a part of the specification and illustrate, by way of example,

preferred forms of the invention which consists in such novel combinations of features as are shown and described herein.

In the drawings:

Fig. 1 is a side elevation, partly in section and with parts broken away, showing one form of apparatus embodying the invention;

Fig. 2 is a view, partly in section and with parts broken away, of the forward extremity of an apparatus embodying the present invention showing the details of a front brush device and the construction of its core;

Patented Mar. 14, 1961 Fig. 3 is a sectional view, with parts broken away, taken substantially along line 3-3 of Fig. 2;

Fig. 4 is a side elevation of a dished plate-like or disclike spacer element of resilient rubber-like material which is employed as a part of a core of a brush device as shown in Fig. 2;

- Fig. 5 is an end view of the element shown in Fig. 4;

Fig. 6 is a side elevation of a pair of brush bristles or tines which are joined in hairpin or U-shaped form and which are employed in the form of the invention shown in Figs. 1 and 2;

7 Fig. 7 is a side elevation, partly in section and with parts broken away, of a brush device embodying another form of the present invention;

Fig. 8 is a fragmentary view of a portion of Fig. 7 but on an enlarged scale showing a modified form of brush bristle;

Fig. 9 is a fragmentary view of a further modification of a brush bristle;

Fig. 10 is a side elevation, partly in section and with parts broken away, of still another form of brush device employed in the present invention;

Fig. 11 is a sectional view taken substantially on line 11-11 of Fig. 10;

Fig. 12 is a perspective view of a sleeve-like core of resilient rubber or rubber-like material which is employed in the form of the brush device of Fig. 10;

Fig. 13 is a perspective view of a portion of a brush core which is employed in the brush device of Fig. 10;

Fig. 14 is a side elevation, partly in section and with parts broken away, of still another form of the invention comprising a reversible apparatus for threading conduits or traveling through pipes, and showing such apparatus located within a pipe and adapted for traveling in one direction, namely, to the left, as viewed in this figure;

Fig. 15 is a sectional view taken substantially on line 1515 of Fig. 14;

Fig. 16 is a fragmentary view on a somewhat enlarged scale of a modification of a brush device which may be employed in the embodiment of Fig. 14; and

Fig. 17 is a fragmentary view of a portion of the brush device of Fig. 16 but in a different operating position.

Referring to the drawings in greater detail, with particular reference to Fig. l, the apparatus shown therein is generally designated 20 and is constituted by a motor 21, to the front and rear extremities of which respectively are connected or secured coaxial brushes 22 and 23, such brushes being, in the form shown, of cylindrical configura'tion having respectively cores 24 and 25 from which protrude outwardly in circumferential array a plurality of bristles, namely, bristles 26 for the forward brush 22, and bristles 27 for the rear brush 23. The cores 24 and 25 of such front and rear brushes each include a rubber or rubber-like layer or sleeve in which are embedded the bristles or tines of the brushes. Such layer or sleeve is designated 28 for the brush 22, and 29 for the brush 23. The sleeves 28 and 29 are supported by centrally extending rigid metal rods 30 and 31, respectively.

The motor 21 is provided with an armature 32 having a shaft 33 which extends longitudinally of the apparatus and coaxially with the brushes 22 and 23. That is, the longitudinal axes of said brushes 22 and 23 and of the motor 21 are in coincidence.

The apparatus of Fig. 1 is caused to advance in a conduit 34, in which. it is inserted, by suitable vibratory means which causes the apparatus to shake or quiver laterally of the longitudinal axis of the apparatus in the manner described in said copending patent application. As shown in Fig. 1 herein, the armature shaft 33 is pro- I vided at opposite extremities thereof with eccentric weights 35 and 36 respectively positioned upon the front and rear extremities thereof which are situated 180 out of phase and which in response to rotation of the armature cause the longitudinal axis of the apparatus to genconduit.

erate a cone, that is, to move in a path conforming to a conical surface of revolution.

In order to permit the use of times or bristles (26, 27) which are as stiff as possible without disadvantageous frictional effects, the aforementioned rubber sleeves 28, 29 are employed. The details of the construction of core 24 are shown in Fig. 2. The employment of the rubber mounting for the bases of the bristles, as in the core 24, permits a change in the angle of each bristle when it is thrust into a pipe thereby to accommodate the smaller inner diameter of the pipe and this Without any appreciable bowing of each bristle by virtue of its relatively stiff nature. Such appreciable or relatively greater bristle bowing militates against the efiicient operation of the apparatus, as aforementioned, by absorbing disadvantageously some of the vibratory power of the apparatus, and causing such vibratory power (e.g. vibratory in generating a conical surface of revolution) to be wasted in increasing the extent of the initial bowing of the bristles rather than in pushing the apparatus through a pipe.

in the form shown in Fig. 2, the brush 24 comprises a plurality of dished plate-like or disc-like spacer elements 37, there being eight in such figure, which elements are consecutively and coaxially mounted, and clamped by suitable end plates 38 and 39 with the aid of the aforementioned rigid central rod 30 which urges such end plates together. Each ofthe dished plate-like elements 37 is of resilient rubber-like material and, with the exception of the one at the right-hand extremity designated 37', is provided with a plurality of U-shaped grooves 40 well illustrated in Fig. 5, which grooves are designed for receiving the inner U-shaped portions of a pair of joined bristles or tines 41 (Figs. 3 and 6).

A plurality of such bristle pairs '41 are thus placed in the grooves 4s prior to pressing the dished plate-like elements 37 together coaxially and such bristles are held in position by clamping such elements 37 together, as shown in Fig. 2. Preferably a suitable adhesive is applied to the adjacent faces of the elements 37 in order to ensure a firm and secure bond between such elements which will prevent the dislodging of the bristles 41 in their grooves 40.

As shown in Fig. 2, forward brush 24 is secured to the front end of motor 21 by means of a plurality of angularly spaced parallel bolts 42, the position of the uppermost one of which is well illustrated in Fig. 3, it passing between the vertical arms of a bristle pair 41. The bolts 42 threadedly engage the motor 21 in the manner shown in Fig. 2 and preferably extend parallel to the longitudinal axis of the apparatus 20.

Reverting to Figs. 3 and 6, it will-be seen that inner extremity 41a of bristle pair 41, when positioned in a groove 49, is spaced from the central rod 30. However, if desired, the grooves 40 for receiving the bristles 41 may be so disposed in each of the spacer elements 37 that such inner bristle extremity 41a is in contact with the rod 30.

Referring to Fig. 1, the motor 21 is energized by electrical power received via an electrical power line 43 which is connected to a suitable source of electrical power (not shown). The power line 43, as is shown in Fig. 1, may be directed to the motor 21 via a passage in a central rod 31 which protrudes rearwardly from the apparatus 20 as shown in such figure. At the aftermost extremity of the rod 31 a suitable eye 44 may be formed which preferably is connected to a cable or cord 45 designed for the purpose of pulling the device 29 backwards out of a pipe or conduit when this becomes necessary.

Referring now to the degree of tilt of the bristles, I have found it advantageous to construct and arrange such bristles whereby the angle of tilt is about 12 to 15 prior to the insertion of the apparatus into a conduit, such tilt increasing to about 25 to 40 when inserted in the Such angle of tilt is, of course, measured at Thus the angle of tilt of the bristles shown in such- Fig. 2 prior to insertion of the brush into a conduit is of the order of 15 and, as shown in Fig. 1, such angle of tilt is of the order of 25".

I have found that this provides suitable traction for the apparatus and by selecting the stifiness of the bristles and the hardness or resilience of the sleeves 28 and 29, a minimum amount of friction is created which will tend to retard the advance of the apparatus and at the same time the degree of bowing of the bristles is also minimized in order to achieve the advantages above set forth with respect to most efi'icient use of the propelling power of the motor 21.

A second embodiment of the invention comprises one identical to that shown in Fig. 1 with the exception that a modified form of brush construction is employed which is illustrated in Figs. 7, 8 and 9.

Such modified form of brush construction is illustrated with respect to a front or forward brush 46 (Fig. 7) which is constituted by a solid sleeve 47 of rubber or rubberlike material of selected resilient qualities, for example, of a rubber hardness of 60-70 Durometer-Shore-A. A similar rubber hardness may be employed with respect to all of the resilient or rubber-like mountings for the bristles described herein.

The resilient sleeve 47 is supported by a rigid central rod 48 which, at its righthand extremity, is secured to the forward end of the motor 21.

The central rod 48 thus provides a rigid support for the sleeve 47 and for the forward brush member, there being embedded in the sleeve 47 a plurality of bristles 49, the inner extremity of one of which is illustrated in Fig. 8. Such bristles 49 (Fig. 8) may be of suitable gauge spring steel such as piano wire having formed at the inner end thereof a barbed hook 50 which resembles somewhat the end of a fishhook. The bristle 49 is installed in the sleeve 47 by thrusting same, at a desired angle, into the sleeve until the pointed extremity engages the rod 48. If desired, a suitable pilot recess or passageway can be preformed in the sleeve 47 to receive each of the bristles 49.

In lieu of the bristle 49 of Fig. 8, bristle 51 can be employed having a plurality of barbs, such as 51a (Fig. 9), formed along the inner part thereof adapted to be buried in the resilient sleeve 47.

As is shown in Fig. 7, the brush construction 46 also embraces end plates 52 and 53 respectively on the forward and rear extremities, such end plates, if desired, exerting a suitable squeezing pressure upon the resilient sleeve 47. Furthermore, if desired, the brush construction .46 may be, as is shown in Fig. 7, attached to the forward end of the motor 21 as by bolts 53a which extend parallel to the longitudinal axis of the rod 48.

Another embodiment of the invention may be employed which also is identical to that of Fig. l with the exception of a modification of the brush construction as shown in Figs. l0l3, inclusive. In Fig. the modified form of brush construction is generally designated 54 and comprises a sleeve 55 also of resilient rubber-like material, which sleeve extends substantially the full length of the brush construction as in the embodiment of Fig. 7 and in which are embedded a plurality of tines or bristles 56. The bristles 56 distinguish from the bristles 49 of the embodiment of Fig. 7 by virtue of a difierent construction of their inner extremities which, in lieu of a'sharp barb 50, employ a curved hook conformation as at 57 which has a rounded end, for example, formed on 3. ,6 inch radius.

The resilient sleeve 55 preferably is provided with a plurality of pilot holes or passageways in which may be inserted the hooked or inner extremity of each brush bristle, the bristle being inserted with the hook first and thrust inwardly (the metal core of the rubber sleeve being removed) until the hook is fully through the rubber or rubber-like wall of sleeve 55 and then the hook is retracted to the position as shown in Fig. 10.

By way of example, overall dimensions of one size of the brush construction of Fig. 10 are as follows:

Inches Outer diameter 4%; Overall length, that is, from the extremity of one end plate to the other 3%;

in Fig. 13, this constituting, for example, the forward one, a similar one being employed in the rear extremity. Such forward element is designated 58 and the rear one 59. The forward element 58 includes a forward end plate 60 with which is integrally formed a stud or post 61 which, in the form shown, in length is one-half the length of the brush construction 54. The element 59 is of analogous construction having an end plate 62 and a central stud or post 63, the inner extremity of which abuts at 64 with the inner extremity of the stud or post 61. The lengths of the studs or posts 61 and 63 are selected for the purpose of giving a desired compressing effect upon the rubber or rubber-like sleeve 55 in which are embedded the bristles 56.

The brush construction 54 is held in an assembled condition preferably by longitudinally extending bolts 65 (Fig. 10) which are, in the form shown, four in number and are spaced angularly by and located near the periphery of the brush construction and which extend into threaded engagement with the front extremity of the body of the motor 21, as is well shown in Fig. 10. Suitable grooves 66 are formed at 90 intervals about the periphery of the sleeve 55 for the purpose of accommodating the longitudinally extending threaded bolts 65.

Referring now to the form of the invention shown in Figs. 14-17, inclusive, there will now be described an embodiment which can be identical to any of the previous embodiments of the invention with the exception that there are in addition provided a relative disposition of the forward and rear brushes and suitable means so that the device is reversible. That is, the angle of tilt of the bristles of the forward brush is opposite to that of the rear brush, and means are provided for covering up selectively one or the other of such brushes as by an axially shiftable cylinder which will permit the uncovered brush to thrust the apparatus in a desired direction, it being understood that the direction of thrust can be reversed by axially shifting the covering device into an opposite position.

Such a reversible form of the duct rodding device, that is, reversible by its own action, is designated generally at 67 (Fig. 14) and is constituted by a motor 68 which preferably is identical with the motor 21 of Fig. l, and to which motor are secured at the opposite extremities thereof a pair of coaxial brushes 69 and 70, the bristles 71 and 72 thereof, respectively, being tilted in opposite directions instead of in a common direction.

For purposes of obtaining a reversal of motion of the apparatus of Fig. 14, there is connected thereto in a manner to be more fully set forth below an axially shiftable cylinder or housing 73 which is of a selected length and which is mounted upon the motor 68 in such a way that it can be shifted axially to a lefthand extreme as shown in solid lines in Fig. 14 wherein it covers the extremities of the bristles 71 thereby immobilizing same insofar as their driving force is concerned, and permitting the righthand brush construction 70 to become the only operable or propulsive brush construction and which, under the influence of the motor 68, will advance the brush to the left, as viewed in Fig. 14.

For the purpose of facilitating the operation of this device, a pair of spider supports 74 and 75 are provided, the latter being illustrated in Fig. 15. Each spider support is capable of supporting its respective extremity of the apparatus in a centered position within a conduit 76 but not concurrently. That is, one or the other is always immobilized.

The function of the spider supports is to ensure that that extremity of the apparatus where the brush is immobilized is held in a central position in a conduit, the spider at the opposite end being immobilized and relying upon the adjacent brush construction for the purpose of holding such opposite end in a substantially centered position Thus in the form shown, the spider support 75 consists of four radially extending legs 77 spaced apart by 90 and each being spring mounted for radial extension or contraction under the influence of coil springs 73 (Fig. 14). Thus each leg 77 is constituted by two portions, namely, a portion 78 upon which is rotatably mounted a wheel 80, the portion 79 being rod-like in conformation and telescopically engaging a tubular portion 81 in the central passage of which is located the aforementioned spring 78 which urges outwardly the portion 79.

The cover or cylindrical housing 73 is provided with suitably conformed openings, such as 73a and 73b, which are of adequate longitudinal extent and suitably positioned peripherally of the housing to ensure that the spider support (e.g. 74) adjacent the housed or covered brush is operative and that the legs thereof extend through their respective openings 73a to permit the respective rollers or wheels St} to engage the inner surface of the conduit 76. And conversely that the other spider support (eg. 75), adjacent the brush which is operative to propel the apparatus, is rendered temporarily inoperative by virtue of its outer Wheels riding upon the interior surface of the housing as is well shown in Fig. 14.

The manner of operatively interconnecting the cylindrical housing 73 to the motor 68 to permit the aforementioned axial relative motion is also shown in Fig. 14 and comprises a series of axially extending rods, such as 82, which are spaced about the periphery of the motor 68 and which are secured thereto as by arms 83 and 84. Such rods in turn pass through passages 850 formed each in an arm 85, the latter being rigidly secured to the inner surface of the cylindrical housing 73 and extending radially inwardly thereof.

The coaction of the rods 82 and the radially inwardly extending arms 85 thus permits axial movement of the cylindrical housing 73 between the limits shown in Fig. 14, that is, between the position of the housing shown at its leftlland extremity in solid lines and the position thereof as shown at its righhand extremity in broken lines.

Any suitable power means can be employed for so axially shifting the cylindrical housing 73 between its extremes of motion in order selectively to activate one of the brushes and deactivate the other. Such means, in the form shown in Fig. 14, comprise a relatively small motor 86 mounted upon the lefthand upper extremity of the larger motor 68 (Fig. 14) to which its drivably connected a threaded rod 87 which engages a threaded recess 88 of an arm 89, the latter being secured to the inner extremity of the cylindrical housing 73. Thus the latter housing 73 can be axially shifted by rotating the rod 87 by the motor 86.

Suitable control means for the motor 86 may be provided. Electrical energy for the motor 86 is directed thereto by an electrical cord 90 which, in the form shown, extends through the brush 70, together with another electrical lead or cord 91, the latter being for conducting electrical energy to the motor 68. Both of the cords and 91 emerge from the righthand extremity of the brush 70 and are bound together to form a joint electrical cord 92 which is connected to suitable sources of electrical energy and control means.

Limit switches 93 and 94 mounted on motor 68 are provided for stopping the motor 86 in response to the cylindrical housing reaching its lefthand or righthand extremity, as viewed in Fig. 14. That is, the switch 93 is positioned for coacting with the radially inwardly extending arm 89 in the manner shown, and when the latter is in its lefthand extremity such switch is actuated to stop the motor 86. Conversely, the switch 94 is positioned for stopping the motor 86 when the housing 73 has moved to its righthand extremity and the arm 89 is in the position shown in broken lines in Fig. 14.

Inner surface 730 of the housing 73, which surface is positioned for engaging the outer extremities of the bristles 71, is preferably formed with a hard and polished surface, for example, a chromium plated surface which is of a degree of hardness to prevent the extremities of the bristle 71 from gaining a foothold thereupon and thereby retarding or hindering the disengagement of such inner surface 73c when it is desired to shift axially the housing 73 to its righthand extremity from that shown in Fig. 14. Analogously the inner surface 73d of the housing 73 is formed with a hard highly polished surface and for a similar purpose.

In order to facilitate the engagement and disengagement of the inner surface of the housing 73 with the ends of the brush bristles of both right and left brushes, the outer end portions of the bristles may be formed as shown in Figs. 16 and 17. That is, bristles 71a (e.g. of the left brush) may be employed which are identical to the bristles 71 with the exception that the outer portions 71b thereof are bowed or bent in a common direction in the manner shown in Fig. 16. The extent of the bowing or bending is not enough to reduce appreciably the traction of the device. However, the extent of such bowing is enough to facilitate the movement of the bristle extremities over the surface 730 and out of the cylindrical housing 73. That is, once the bristles 71a are housed by the cylindrical housing 73, as shown in Fig. 17, the latter being of considerably less inner diameter than the inner diameter of the conduit 76, there is a tendency for the bristles to gain a foothold or dig into the inner surface 73c and this tendency is minimized by the bowing of the outer portions of the bristles aforementioned, namely, at 71b.

Analogous bowing in the opposite direction of the outer extremities of the bristles of the opposite brush, of course, can be employed if desired.

Reverting to Figs. 1 and 2, there is no bowing of the bristles 26 in the form shown in the brush construction in Fig. 2 because the brush is not inserted within a conduit. However, in Fig. 1, which represents the apparatus inserted in a conduit, there is an enhancement of the tilt of the bristles as compared to Fig. 2 and a slight but almost imperceptible bowing, the extent of the bowing being reduced to a minimum by virtue of the rubber or rubber-like mounting for the bristles.

In the construction of a brush device in accordance with the present invention, it is desirable, in order that it works at optimum efficiency, to employ relatively stiff bristles, as aforementioned, which should be able to deflect or tilt to accommodate easily the full range of conduit diameters for which designed, the outer dimension of the brush before insertion, of course, being somewhat larger than the inner dimension of the conduit.

When the brush is inserted in a conduit, the bristles deflect, that is, they undergo some bowing and also some angular shifting. It is desirable to be able so to shift the bristles angularly With the least possible bowing, for reasons aforementioned, and this can be accomplished by means of the resilient rubber or rubber-like bristle mounting means described herein which permits the most economical utilization of the power ofthe motor. Thus in the present invention it is possible to achieve a bristle deflection as a result of insertion into the conduit and with a minimum amount of bowing. It is, of course, substantially impossible to employ a bristle of the length and diameter herein needed without some small degree of bowing but such is reduced to a minimum by the construction embodying the invention.

Thus the bristles employed herein tilt by moving angularly relative to the rubber core in which they are embedded and with a relatively low degree of bending or bowing whereby, in response to insertion of the apparatus into a pipe, the bristles are as straight as can be attained under the circumstances thereby preventing wasting of the propulsive power of the vibratory motor in causing further bowing of the bristles. The vibratory power of such motor thus can be devoted to the advancing of the apparatus by causing a pushing by the outer extremities or feet of the bristles and without devoting such power to bending or bowing of the bristles.

Consider, for example, a construction embodying the present invention wherein the outer diameter of the brushes prior to insertion into a conduit is 12 /2 inches. It is to be expected that the range of inner diameters of conduits in which such a device can be employed is about 2 inches, that is, say 12 inches down to inches in inner diameter. It is desirable to attain a bristle tilt in response to insertion into the conduit which is sufiicient to permit one to push the apparatus into any size of duct within the selected range, such as that aforementioned, and yet have the bristles remain relatively stifi and straight. By such construction it is possible to accomplish the objectives of the present invention. That is, by means of the present invention one may make use of very stiti bristles which will permit tilt by virtue of the resilient bristle mounting but with little or no bowing of the bristles, that is, without appreciable bowing.

The outer diameter of a brush constructed in accordance with the present invention may be 4%; inches to be inserted into a conduit having a 4 inch inner diameter. A typical example of the thickness of a bristle embodying the present invention is 32 mils to 39 mils, the material being piano wire.

The bowing of the bristles has been used as the means for reducing the brush diameter so that the brush can fit into a pipe of smaller diameter but this is at a cost of the forward thrust of the apparatus and results in wasting part of the power of the propulsive means. Thus, much of the power can be so wasted in the bowing of the bristles instead of in pushing the device through the conduit. There are two sources of waste, namely, loss of physical push or forward thrust due to bowing and also such loss due to friction between the bristles and the duct, for example, when the brushes are too tight in the conduit. The above disadvantage can be overcome and the best results obtained if the bristles can assume the right angle relative to the inner wall surfaces of the conduit, for example, 25 and still be relatively straight, that is, with no appreciable bowing. This advantage is obtained by the construction of the present invention. However, it is to be noted that even when the stiffest of bristles is employed, there is some degree of bowing because it is not possible to employ a bristle construction which is not subject to at least some small degree of bowing when the device is thrust into a conduit of smaller diameter than the normal outer diameter of the brush.

Thus, by means of the present invention, there is provided a duct crawler or duct threading device which permits the use of the stifiest possible bristles, the characteristics of which can be selected such that the device does not fit too tightly in a conduit and the device, by virtue of the brush construction, will nevertheless make the most economical use of the power of the motor by gaining a maximum forward thrust at a maximum speed of advance in the pipe due to the minimizing of such bowing.

Referring to the embodiment of Fig. 2, it is desirable to clamp tightly together the conical plate-like discs with the bristles located therebetween because it is possible to obtain the benefit of tilt due to compressibility of the resilient rubber-like discs and with minimum degree of bowing. Furthermore, the cushion effect of the rubberlike material prevents excessive localized cold working of the bristles at any point along the length thereof which will tend to cause fracture.

One of the important advantages obtained by the construction of the device herein described is the elimination of the tendency of the device to rotate when it strikes an obstruction in a pipe. Furthermore, by means of the embodiment of Fig. 14, it is possible to reverse the direction of movement of the apparatus without any damage to its brushes.

By means of the construction shown and described herein it is possible to employ more stifi' Wire or bristle substance of larger diameter as compared to that shown in the above-identified copending patent application.

What is claimed is:

1. Apparatus for traveling through pipes and the like comprising: a brush device constituted by an elongated core and a plurality of bristles extending outwardly therefrom in circumferential array and being tilted relatively to the longitudinal axis of such core when inserted into a pipe, said core including a layer of resilient rubber-like material supported by a rigid central support, said bristles being embedded in said layer; and means for causing said device to quiver laterally of its longitudinal axis to advance the apparatus in the pipe, said bristles being of metal and being of dimensions and of metal characteristics selected to make same stifi to such an extent that together with the selected resilience of said rubber-like material there is substantially imperceptible bowing of the bristles when so inserted in a pipe the inner diameter of which bears relation of the outer diameter of said brush device as defined hereinafter, the outer diameter of said brush device being of the order of about 4% to 25% larger than the inner diameter of such pipe in which it is to operate, and the bristle tilt relative to a plane normal to the longitudinal axis of the apparatus being not greater than about 25 to 40 when inserted in such a pipe.

2. In apparatus for traveling through pipes, a pair of brushes, each having a plurality of stiff bristles extending outwardly from a central elongated core in circumferential array adequate in number to support said core spaced from the inner walls of a pipe and being tilted relatively to the longitudinal axis of such core when inserted into the pipe, a motor, said brushes being coaxially mounted on opposite portions of such motor, means drivably connected to said motor for shaking said brushes in a direction transverse to the common axis thereof, said core being of a resilient rubber-like material and said bristles being embedded therein, said bristles being of metal, the resilience of the rubber-like material, the metal characteristics and the dimensions of the bristles all being selected to cause the rubberlike material to be sufiiciently yielding and to make the bristles sufiiciently stiff whereby there is substantially imperceptible bowing of the bristles in response to the insertion of the apparatus into a pipe, the aforementioned tilted attitude of the bristles being not greater than of the order of 25 to 40.

3. In apparatus for traveling through pipes and the like, an elongated brush constituted by a core having a plurality of relatively stifi bristles extending angularly outwardly from the core in circumferential array adequate in number to support the core spaced from the inner surfaces of a pipe, such core comprising a rigid central rod surrounded by a sleeve of resilient rubberlike material in which are embedded the inner extremities of said bristles, and means connected to such brush for shaking same laterally of the longitudinal axis thereof to cause the apparatus to advance in a pipe,- said bristles being normally straight and having an angle of pretilt prior to the insertion thereof into a pipe of the order of 12 to 15, the outer diameter of said brush device being of the order of about 4% to 25% larger than the inner diameter of the pipe in which it is to operate, and the bristle tilt relative to a plane normal to the axis of the apparatus not greater than about 25 to 40 when inserted insuch a pipe, said bristles being of dimensions and metal characteristics selected to make same of a stiffness whereby, together with the selected resilience of said rubber-like material, there is substantially imperceptible bristle bowing when inserted in such pipe.

4. Apparatus for traveling through a tube having a passage therein of substantially uniform cross-sectional dimensions and comprising in combination a pair of coaxial brush-like devices, each having a core member and a plurality of relatively stiff bristles extending outwardly therefrom in a plurality of directions for supporting such core member spaced from opposite sides of such passage, said bristles being adapted to assume 7 tilted attitudes in a generally common direction relative to the longitudinal axes of such core membersin response to insertion of said brush-like devices into such passage, and a motor connected to said core members and supportable in between the same when in a passage, and means drivably connected to said motor for rapidly moving portions of such core members from one side to another of a norm axis extending in the same direction as the axis of such passage thereby to advance the apparatus in the passage, and characterized in that each of such core members includes a layer of resilient rubher-like material in which are embedded said bristles, the outer diameter of said brush-like devices being of the order of about 4% to 25% larger than the diameter of'such passage, and the resilience of said rubher being selected and said bristles being of dimensions and metal characteristics selected to make said bristles of a stiffness such that there is no bowing or substantially imperceptible bowing thereof when inserted in such pipe.

5. Apparatus for traveling through a tube having a passage therein of substantially uniform cross-sectional dimensions and comprising in combination a pair of coaxial brush devices, eacn having a core member and a plurality of relatively stiff bristles extending outwardly therefrom in a plurality of directions for supporting such core member spaced from opposite sides of such passage, the bristles of one of such brush devices being tilted in an opposite direction relatively to the bristles of the other brush device, a motor connected to said core members and supportable in between same when in such a passage, means drivably connected to said motor for rapidly moving portions of such core members from one side to another of a norm axis extending in the same direction as the axis of such passage thereby to advance the apparatus in the passage, said apparatus being characterized in that each of such core members includes a layer of resilient rubber-like material in which are embedded said bristles, and a sleeve-like device embracing a portion of such apparatus and mounted for axial movement relative thereto for selectively immobilizing one or the other of such brush devices by surrounding same.

6. Apparatus for traveling through pipes and the like having a passage therein of substantially uniform crosssectional dimensions and including in combination, a brush device having a core to which are secured a plurality of relatively stiff bristles which are tiltable in a common direction in response to insertion of the apparatus into such pipe, said bristles extending outwardly from and disposed for supporting said core insuch pipe spaced from and thus between opposite inner surfaces of the pipe, the transverse dimension of said brush device being selected to effect engagement of such opposite inner surfaces of the pipe simultaneously by such bristles, a; motor connected with and supported by said brush device, and means drivably connected to said motor for vibrating said brush device laterally of the longitudinal axis thereof thereby to advance the appa'rat'us through the pipe, said brush device being characterized in that the core thereof includes resilient rubber-like means in which the bases of said bristles are embedded, the resilience of such rubber-like means, and the stiffness of such bristles being selected whereby said bristles undergo no bowing or substantially imperceptible bowing in response to insertion of the apparatus into a pipe, such bristles being of metal and being of metal characteristics of spring steel, such transverse dimension of such brush device being of the order of about 4% to larger than the inner transverse dimension of the pipe in which it is to operate. 1

7. Apparatus for traveling through pipes and the like having a passage therein of substantially uniform crosssectional dimensions and including in combination, a pair of coaxial brush devices each having a core to which are secured a plurality of relatively stiff bristles, the bristles of one core being tilted in a direction opposite to those of the other core, said bristles extending outwardly from and disposed for supporting said cores in such pipe spaced from and thus between opposite inner surfaces of thepipe, the transverse dimension of said brush devices being selected to efiect engagement of such opposite inner surfaces of the pipe simultaneously by such bristles, a motor connected with and supported by said brush devices, and means drivably connected to said motor for vibrating said brush devices laterally of the longitudinal axis thereof thereby to advance the apparatus through the pipe, and a sleeve-liketdevice embracing a portion of such apparatus, and means for mounting such sleeve-like device for axial movement relative to such coaxial brush devices for selectively immobilizing one or the other of such brush devices by I surrounding the outer extremities of the bristles thereof.

8. In apparatus for traveling through pipes and the like, the combination of: a pair of bru'shlike devices each having a core member and relatively stiff fingers secured to the core member, such fingers being adapted to assume in contact with the inner surface of such pipes a tilted attitude in a generally common direction relative to the longitudinal axis of such core members, such longitudinal axis extending'substantially in the proposed direction of motion of such apparatus, such fingers be ing secured to such core member and extending outwardly therefrom in circumferential array for supporting the core member in a pipe spaced from the inner wall surfaces of the pipe; and means operatively connected to said core member for vibrating such core member to generate a substantially conical surface of revolution thereby to advance the apparatus through a pipe, characterized in that each core member includes resilient rubber-like means for mounting said fingers, said fingers being of metal, the resilience of the rubber-like means and the metal characteristics and dimensions of the tingers all being selected to cause the rubber-like means to be sufiiciently yielding and to make the fingers sufficiently stiff whereby there is substantially imperceptible bowing of the fingers in response to the insertion of the apparatus into a pipe, the aforementioned tilted attitude of the fingers being of the order of 25 to 46.

9. In apparatus for traveling through a tube having a passage therein of substantially uniform cross-sectional dimensions, a' pair of brushes each having a core including resilient sleeve means supported by a rigid center rod and a plurality of relatively stiff bristles embedded in said sleeve means and extending outwardly therefrom in at least two opposite directions for supporting such cores spaced from opposite sides of such passage, said bristles being adapted to assume, substantially free of bowing, tilted attitudes in a generally common direction relative to the longitudinal axis of such cores when said brushes are inserted into such passage; and means in connection with said brushes and supported between and by such brushes for rapidly moving portions of such core members from one side to another of a norm axis thereby to advance the apparatus in the passage, said bristles being of metal, the resilience of said sleeve means and the metal characteristics and dimensions of said bristles all being selected to cause the sleeve means to be sufficiently yielding and to make the bristles sufliciently stiff whereby said bristles as aforementioned are substantially free of bowing when said brushes are so inserted into such passage; the aforementioned tilted attitudes of the bristles being not greater than of the order of 25 to 40 relative to a plane normal to the axis of the brushes, the inner extremities of said bristles being spaced from the aforementioned rigid center rod while so embedded in said sleeve means thereby to enable each bristle to react against the tube and be pushed inwardly against the resilient material of the sleeve means in response to a reverse thrust acting on the apparatus of sufiicient magnitude to reverse its movement and thus produce a reverse tilt of said bristles, thereby ing bowing of the bristles when the apparatus is reversed in motion through the passage.

References Cited in the file of this patent UNITED STATES PATENTS 116,823 Farley July 11, 1871 1,142,513 Churchill Sept. 12, 1939 2,654,433 Piety Oct. 6, 1953 FOREIGN PATENTS 614,592 Great Britain Dec. 17, 1948 775,106 Great Britain May 22, 1957 799,733 Great Britain Aug. 13, 1958 1,142,513 France Apr. 1, 1957

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