Abstract:
An instrument for temporarily preventing fluid flow along a pipe utilizing a manually actuatable handle, a seal assembly and a flexible cable releasably connected between the handle and the seal assembly. The handle includes a handgrip and a depressible lever pivotally connected to the handgrip to articulate a handle and wire within a sleeve respectively connected to a first and second compression element to expand by compression an elastomeric seal captured therebetween.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the field of tools used in the installation and maintenance of plumbing conduits and pipe, and in particular concerns an improved hand operated tool for temporarily plugging pipe to exclude liquid during a pipe soldering operation or while other work is done on or near the open pipe end. 
     2. Description of the Prior Art 
     Many tools are known and used in the plumbing trade for the aforementioned purpose. In general, such tools have a seal element which is introduced into an open end of a pipe to be soldered and is expanded in diameter to make a water tight seal inside the pipe. 
     The existing tools are cumbersome, costly and require frequent replacement of parts. A continuing need exists for such tooling which is long lasting and safe to operate at low cost. 
     SUMMARY OF THE INVENTION 
     The present invention addresses the aforementioned need by providing an instrument for temporarily sealing a pipe against fluid flow which has a manually actuatable handle and a sealant unit engaged to the handle. The sealant unit has a seal assembly and a flexible cable operatively connecting the handle and the seal assembly. The seal assembly has a thermoplastic elastomeric seal contained between first and second compression elements along an axial direction of the cable. The thermoplastic elastomeric seal is far longer lasting than other elastomers such as rubber. When rubber seals are exposed to heat, as required in soldering for example, “dry rotting” occurs, which drastically reduces the seal life. The seal of the present invention, therefore, reduces replacement costs. 
     The cable is operative for urging the compression elements together thereby to achieve expansion of the thermoplastic elastomeric seal in a radial direction responsive to manual actuation of the handle from a normal to a depressed condition. Preferably the actuating handle includes locking elements for retaining the handle in a depressed condition when actuated, so that sealing engagement of the seal with the interior surface of a pipe can be maintained without further effort on the part of the user while repair or maintenance work is performed on the pipe. 
     The actuating handle may have first and second handle members, such as a handgrip and a lever, movable relative to one another from a normal to a depressed condition. The cable may have a sleeve connected at one end thereof to a first handle member and at an opposite end thereof to one of the compression elements, and a wire axially slidable in the sleeve, the wire being connected at one end thereof to a second member of the handle and at an opposite end thereof to another of the compression elements, such that the wire is retracted into the sleeve responsive to relative movement of the handle members. The wire may pass through the first compression element and through the thermoplastic elastomeric seal. 
     The sleeve is preferably a flexible compressed steel spring to allow maximum flexibility of the cable. Whereas other flexible steel tubing is susceptible to fatigue and fracture upon repeated bending, as through elbows in piping, the compressed steel spring resists such fatigue, thereby increasing the life of the cable. 
     The cable may alternatively have a sleeve connected at one end thereof to a first handle member and at an opposite end thereof to a connector. This connector is adapted to allow mating engagement of the cable to a modified sealant unit. The modified sealant unit includes a seal assembly and a cable portion. The cable portion is attached to the seal assembly and is further adapted to allow mating engagement between the modified sealant unit and the connector of the cable thereby allowing the user to simply detach the sealant unit from the cable when such becomes desirable. Therefore, the sealant unit may be replaced separately from the cable so that when one or the other becomes worn the entire piece consisting of the cable and sealant unit will not need to be replaced. Due to uneven wear between these two components, this function is highly desirable. 
     The thermoplastic elastomeric seal element is expanded radially by axial compression of the seal element between the compression elements. In such case the seal element may be axially mounted to the cable. In one embodiment of the invention, the thermoplastic elastomeric seal is expanded by stretching to an increased radius, as by being displaced axially on a tapering surface such as a conical surface. In the latter case, one compression element has the tapering surface and the other compression element urges the seal element along the tapering surface in a direction of increasing width to stretch the seal element. The tapering surface may be a frusto-conical surface coaxial to the cable. 
     The first element of the handle may be a handgrip and the second element of the handle may be a depressible lever pivoted to the handgrip. The locking elements of the actuating handle may be detent elements on each of the handgrip and the lever engageable with each other upon depression of the lever. The detent elements may operate in the manner of a ratchet, such as a series of teeth on said depressible lever sequentially engageable with a tooth detent on the handgrip during progressive depression of the lever. Desirably, the locking elements will retain the lever against return to a normal condition through a range of depressed conditions until the locking elements are disengaged from each other by the user of the tool. 
     Safety features are included to protect the user from discomfort resulting from depression of the lever. One such feature is the finger barrier. Upon depression of the lever, a user&#39;s small finger may be pinched between the lower ends of the handgrip and the lever. Moreover, the impact of the lower end of the lever against the small finger of the user upon depression may likewise cause substantial discomfort. Therefore, a finger barrier is provided to protect the small finger of the user from either of these occurrences. 
     Another safety feature provided is the hand barrier. The hand barrier is provided on the lever to prevent pinching of the portion of the users hand between the index finger and the thumb when utilizing the device. 
     In one form of the invention the sealant unit is removably engaged to the handle such that different sealant units, each having thermoplastic elastomeric seals of different radial dimension, may be interchangeably engaged to the handle so as to fit a pipe of given standard diameter. Therefore the cable may be disengageable from the handle such that different sealant units each having its own cable and seal assembly may be interchangeably engaged to the handle, so that a tool kit including multiple sealant units each with a seal assembly of different diameter may be provided. 
     In another form of the invention a modified sealant unit is releasably attached to a cable adapted at both ends to be releasably attachable to the modified sealant unit at one end and the handle at the other end. Therefore, the modified sealant unit can be removed from the handle either alone or in conjunction with the cable. 
     In yet another form of the invention, the actuating handle may have a third member which is adopted to releasably attach to the cable. The handle may have a channel with a wire section therein connected to a first handle member at one end and the third handle member at the opposite end. Within this channel, an axially disposed spring member may be included to bias the wire toward the third handle member. Therefore, the cable may be releasably attached to the handle quickly and easily. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a side view partly in section showing the hand grip in normal position; 
     FIG. 1B is a side view of the seal assembly inserted into a pipe in the normal condition corresponding to the handle position of FIG. 1A; 
     FIG. 2A is a view as in FIG. 1A showing the hand grip in depressed condition for actuating the seal assembly; 
     FIG. 2B is a view of the seal assembly actuated to an expanded diameter for making sealing engagement with the interior wall surface of the pipe; 
     FIG. 3 is a sectional view in an axial direction of an alternate seal assembly suitable for larger diameter pipe, the seal being shown in its normal condition within El pipe; 
     FIG. 4 show the seal of FIG. 3 in actuated condition to make sealing engagement with the interior wall surface of the pipe. 
     FIG. 5 is a side view partly in section showing the modified hand grip in normal position; 
     FIG. 6 is a side view partly in section showing the modified hand grip in depressed condition for actuating the seal assembly. 
     FIG. 7 is a view of the seal assembly with the end connection which allows replacement of the seal assembly without disconnecting the sleeve. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. 
     With reference to the accompanying drawings, the hand tool shown in part in each of FIGS. 1A and 1B. generally designated by the numeral  10 , has an actuating handle  12  to which is an interchangeable sealant unit  14 . The sealant unit  14  includes a flexible cable  16  and a seal assembly  18 . 
     The handle  12  has a handgrip  20 , and a lever  22  pivoted by a spindle at  24  to the handgrip. The handgrip, lever and spindle may all be made of a suitable heat resistant plastic molded in two pieces and screwed together or may be made of metal with a plastic or rubber covering. Depression of the lever to the depressed position shown in FIG. 2A, as by squeezing the handle in the hand of an operator, causes the upper ends of the lever and the handgrip to move apart from each other. 
     The cable  14  has an outer sleeve  26  and a wire  28  axially slidable in the sleeve. The wire  28  may be {fraction (1/16)}th inch flexible steel wire (braided type), while the sleeve may be a flexible compressed steel spring, approximately 20 inches long and {fraction (5/32)} inch in diameter. One end of the sleeve  29  is fitted to the upper end of the handgrip at  30  and the corresponding end of the wire lies within a channel, slot or groove  32  extending along the upper ends of both the handgrip and the lever and is engaged to the upper end of the lever by an enlarged bell-shaped plastic anchor  34 . The bell shape of the anchor  34  is such that the operator may readily grasp the anchor to engage the seal unit to the handle. Therefore, an exposed portion of the wire  28  extends from the end  29  of the cable sleeve along the slot  32 , so that the wire end is removably secured by the anchor  34  at one end of the slot and the sleeve end  29  is removably secured to the handle at the opposite end of the slot  32 . The length of the exposed wire portion in the slot is such as to maintain sufficient tension against the handle at the opposite ends of the slot to retain engagement of the cable to the handle. 
     FIG. 5 shows another form of the invention in which the handle actuator is; a self-contained unit and is separate from the cable, but is attachable thereto by means of a connector  21 . In this form of the invention, the handle  12  has a handgrip  20 , a lever  22  and a connector  21 . A wire  31  is permanently located within channel  32  and attached at one end to the upper end of the lever  22  and attached at the other end to the connector  21 . This connector is spring loaded by a compressed spring  21  a to bias the wire  31  in the direction of the connector shown by arrow  1 . Therefore, when in the normal position (FIG. 5) a portion of the wire  31  protrudes from the connector  21 . The end of the wire protruding outward is adapted to matingly engage the wire  28  of the sealant unit  14 . 
     The opposite end of the sleeve  26  carries a stationary compression plate  36 . The wire passes through the center of the stationary compression plate  36  and through a disk shaped thermoplastic elastomeric seal  40 , and supports at its opposite end a movable compression plate  38 . The seal  40  is disk shaped with a lens shaped central area of increased cross-sectional thickness, as seen in FIG.  1 B. The compression plate  36  is circular and dished to generally conform to the convex curvature of the lens shaped center of the seal  40 . The compression plate  38  is disk-shaped also with a lens shaped central area of increased cross-sectional thickness. The increased cross-sectional area on the compression plate  38  reduces the possibility of the plate shearing due to forces thereon by the compression of the lever. The diameter of the compression plates  36 ,  38  is slightly undersized to the diameter of the pipe P, as is the normal, uncompressed diameter of the seal  40 . 
     Actuation of the handle  12  causes the upper end of the lever to pull on the wire  28  by means of the bell-shaped anchor  34 , retracting the wire  28  into the sleeve  26  and urging the movable compression plate  38  against the stationary compression plate  36 . The thermoplastic elastomeric, seal  40  is compressed between the plates  36 ,  38  in an axial direction of the wire  28  and expands in a radial direction of the wire  28 . In an initial uncompressed condition of the seal  40 , shown in FIG. 1, the seal has a diameter smaller than the inside diameter of the pipe P which is to be temporarily plugged. Upon actuation of the handle  12  the diameter of the seal  40  expands into  9  sealing engagement with the interior of the pipe P, as illustrated in FIG. 2B, to contain water flow W. 
     The self contained handle functions similar to the handle described above wherein the bell anchor  34  of the sealant unit is attached to the upper end of the levier  22 . In this alternative form of the handle, (FIGS. 5 &amp; 6) a wire  31  is disposed in a channel, slot or groove  32  along the upper ends of the handgrip and the lever. This wire  31  is engaged to the upper end of the lever by the bell shaped plastic anchor  34  at one end and the connector  21  at the other end. The wire  31  is biased forward toward the front of the handle by a spring located at the connector  21  and attached to the wire  31 . A portion of the wire  31  protrudes from the front of the handgrip  20  through the connector  21 . 
     Actuation of the handle  12  causes the upper end of the lever to pull on the wire  31 , thereby retracting the wire portion protruding from the front of the handgrip  20  into the channel of the handgrip  32 . When the wire  31  is matingly attached to the wire  28  of the sealant unit  14  such retraction of the wire  31  causes the moveable compression plate  38  to move against the stationary compression plate  36  forcing the radial expansion of the thermoplastic seal  40 . 
     The handle  12  has locking elements operative for retaining the lever  22  in depressed condition, so as to maintain sealing engagement of the seal element  40  with the pipe P without further manual force applied to the handle  12 . The locking elements, shown in disengaged condition in FIG. 1A, are a series of four teeth  42  on an upward facing surface of the bottom of the lever  22 . The teeth  42  sequentially engage with a  10  detent tooth  44  dependent from the bottom of the handgrip  20  as the lever is depressed towards the handgrip  20 , in the manner of a ratchet. Sealing engagement with the pipe P is maintained until the interlocking teeth  42 ,  44  are disengaged from each other arid the lever  22  is returned to its initial position of FIG. 1A, allowing the wire  28  to extend from the sleeve and slide to its normal position in the same Figure thereby separating the two compression plates  36 ,  38  which in turn permits the elastomeric seal  40  to expand axially and retract radially to its normal diameter. The seal assembly  18  may then be withdrawn from the pipe P by pulling away the handle  12 . 
     To prevent the operator&#39;s hand from being pinched in actuating the handle, safety barriers may be added. A hand barrier  35  is formed from the upper portion of the lever so that the flesh between the operator&#39;s thumb and index finger is not caught under the plastic anchor  34  while actuating the handle. Likewise, a finger barrier  45  is added to prevent the skin of the operator&#39;s small finger from being caught between the lower ends of the lever and handgrip while actuating the handle. 
     The sealant unit  14  is interchangeable on the handle  12  with other similar sealant units which differ in the diameter of the elastomeric seal  40 , and in the size of the compression plates  36 ,  38  needed for compressing each particular size of elastomeric element. The operation of each interchangeable sealant unit  14  by means of the actuating handle  12  remains the same, however, the methods of attachment may vary. 
     In one form of this invention, the channel  32  of the handle is exposed to view from atop the handle. This opening allows the user to connect the end of the sealant unit  14  having the wire  28  exposed and the anchor  34  attached, thereto, to the handle.  11 . 
     The user attaches the sealant unit to the handle by first positioning the end portion sleeve  30  into a slot  29  at the front of the handgrip  20 . The user then places the exposed portion of the wire into the channel  32  of the handle and connects the anchor  34  to the top rear portion of the lever  22 . 
     In another form of this invention the channel  32  of the handle is not exposed to view from atop the handle. In the self contained handle, the wire  31  is permanently disposed within the channel  32  and connected to the lever  22  at the top end thereof by the anchor  34  and to the handgrip at the connector  21 . The sealant unit is therefore connected to the handle by means of connector  21 . Connection of the wire  31  of the handle  12  and the wire  28  of the sealant unit may be accomplished by a number of different means. Shown in FIG. 5, the end of wire  31  is threaded so as to engage a similarly threaded female adapted connector  27 . A sleeve portion (not shown) may be snapped on this portion to protect the exposed wire  31 ,  28  connection. Further, a similar connector may be added to the end of the cable  16  proximate the seal assembly  18  to allow replacement of the seal assembly  18  and cable  16  separately. 
     FIGS. 3 and 4 depict an alternative form  18 ′ of the seal assembly for use with the actuating handle  12  according to this invention. The alternate seal  18 ′ also has two compression elements  46  and  48  which have an annular surface  50  on one compression element axially facing a frusto-conical surface  52  coaxial with wire  28  on the other compression element. An elastomeric element in the form of annular rubber gasket  54  is seated on the frustoconical surface  52  near the smaller diameter, inner end of the surface  52 . A cylindrical projection  56  of the compression element  46  slides axially in a cylindrical recess  58  defined in the compression element  48 , to restrict the two compression elements to axial movement relative to each other in response to actuation of the handle  12 . Actuation of the seal assembly  18 ′ is similar to that described in connection with the seal assembly  18  of FIGS. 1A through 2B. Depression of the lever  22  relative to the handgrip  20  causes retraction of the wire  28  into the sleeve  26 . The end of the wire is anchored at  60  to the center of compression element  48  and draws that compression element against compression element  46 . The annular surface  50  advances axially against the frusto-conical surface  52  and urges the annular gasket  54  towards the larger diameter end of the frusto-conical surface  52 , thereby stretching the gasket  54  from its normal, initial diameter of FIG. 2 to an expanded outer diameter which, as shown in FIG. 4, slightly exceeds the outer diameter of both compression elements  46  and  48 . The radial dimensions of the compression elements, the taper of the frustoconical surface  52  and the expanded outer diameter of the rubber gasket  54  are selected and configured such that the periphery of gasket  54  makes radial sealing engagement with the cylindrical interior wall of a pipe P of given diameter. 
     Pipes typically encountered in the plumbing trade, primarily copper pipe, are in a relatively small number of standardized pipe diameters, and the present invention contemplates a tool kit which includes an actuating handle  12  and a number of sealant units  14 , each sealant unit having a seal assembly  18 ,  18 ′ sized to make sealing engagement with a different pipe diameter, so as to cover a range of pipe diameters, preferably a range of pipe diameters most likely to be encountered by the plumbing personnel for whom the tool kit is intended. 
     It has been found that the seal assembly configuration of FIGS. 1B,  2 B while relatively simple to make, is best suited for smaller diameter pipes, for example, from about one-half inch diameter to about one inch in diameter due to the greater compression force needed to achieve sufficient radial expansion in larger sizes of the thermoplastic elastomeric seal  40 . The more complex seal assembly of FIGS. 3 and 4 is easier to actuate for larger diameters of the elastomeric gasket  54  than the disk seal  40  of FIGS. 1B,  2 B. 
     The water supply valve (not shown in the drawings) to the pipe P should be closed during repair or maintenance procedures using the tool  10  of this invention because the seal assemblies  18  and  18 ′ are not intended to seal against a high pressure water supply, but rather to exclude residual water W in the pipe system from the portion of the pipe P being worked on.