Apparatus for removing and installing plumbing flanges

Information

  • Patent Grant
  • 6343411
  • Patent Number
    6,343,411
  • Date Filed
    Monday, February 28, 2000
    24 years ago
  • Date Issued
    Tuesday, February 5, 2002
    23 years ago
  • Inventors
  • Examiners
    • Watson; Robert C.
    Agents
    • Nissle, P.C.; Tod R.
Abstract
An extractor tool for removing and replacing a plumbing fixture, such as a leaking, rusted tub shoe flange with or without cross hairs, includes a shaft having left-handed threads over most of its length and a frusto-conical wedge near one end terminating in a plurality of axial lugs forming a castle around an axial recess, the other end of the shaft being flatted to receive a wrench. A plurality of separate, arcuate shaped, shoes are slidably positioned around the threaded portion of the shaft and are maintained there by a flexible o-ring forming an expandable body having a central bore portion and at least the inner end adjacent the frusto-conical wedge of the shaft formed with a tapered circular recess. A washer and nut are assembled on the shaft from the threaded end. Both inner ends of the shoes may be formed with the tapered circular recess to make them reversible. The outside surfaces of the shoes and lugs may be knurled for added gripping. The lugs may be tapered and long to aid in engaging deep cross hairs for removal and installation and to accommodate tall toe stop stems. To remove the fixture the castle end is inserted into the flange drain hole, the nut is turned counterclockwise by hand to expand the shoes into a holding grip with the inside adjacent wall structure of the fixture, further counterclockwise turning of the nut with a wrench both tightening the grip and unscrewing the flange. To replace the new flange, insert the castle end into the flange drain hole atop the cross hairs with the lugs in the openings therebetween and turn the shaft clockwise to screw in the flange and tighten with a wrench.
Description




BACKGROUND OF THE INVENTION




1. Fields of the Invention




The present invention relates generally to apparatuses and methods of removing and installing plumbing flanges, and, more particularly, to removing and installing tub shoe flanges with or without cross hairs, pop up assemblies, lavatory drain flanges, and stub outs of various types with a tool that inserts into the flange drain hole, expands against the inside walls of the drain hole, and by continued counterclockwise turning, unscrews the flange.




2. Discussion of Background and Prior Art




a. The Problem Of Removing A Tub Shoe Flange Without Damaging The Tub




One of the significant problems repeatedly faced by plumbers is the removal of a tub shoe flange without damaging the tub.




Shown in

FIG. 1

is a typical tub shoe installation


10


which includes polyvinyl chloride pipe


12


connecting at one end to the house drain line


14


and having a tub shoe


16


at the other end with brass thread fitting


18


therein to go against tub


20


drain hole


22


from below the tub and receiving tub shoe flange


24


into tub shoe fitting


18


from above the tub to form a sealed tub drain (sealing washers or plumber's putty not shown). Tub shoe flange


24


has external threads


26


and cross hairs


28


integral therewith. To open and close the drain opening, cup


30


has washer


32


on its lower side and receives through its bore


33


spindle


34


having threads


36


which screw into the threaded opening


29


in the cross hairs. Cap


38


screws


40


into cup


30


to enable the user to pull up on cap


38


to open the drain or push down on cap


38


to close the drain.




When the tub shoe flange


24


has been in place for a long time and needs to be replaced, plumbers find that the tub shoe flange


24


has often become rusted to the tub shoe


16


brass fitting


18


and that there is nothing to grab onto to use to unscrew the rusted flange


24


from the fitting


18


except the cross hairs


28


. A typical prior art tool known in the trade as an “easy out” (

FIG. 3

) with left-handed threads


52


and a square head


54


adapted to receive a wrench for counterclockwise turning to remove studs and the like will not work in this application since it is too tall, too thin to grab the walls


25


of the flange


24


and too big to fit in the threaded opening


29


in the cross hairs.




If the cross hairs


28


are still in the tub shoe


16


, a better choice is the tool known in the trade as a “dumbbell tool”


60


(

FIG. 4

) having different size castles


62


and


64


at opposite ends. If the outside diameter of one end is small enough to fit into the tub shoe flange central opening


27


, the lugs protruding from the castle, if they are long enough, fit into the respective openings


31


between the cross hairs


28


, and then a wrench can be applied to the dumbbell central portion


66


to turn it counterclockwise to unscrew the tub shoe flange


24


from the tub shoe fitting


18


. The problem usually encountered at this point is the cross hairs


28


, weakened by rusting or corrosion, break off.




Confronted now with a “frozen” leaking tub shoe flange


24


and no cross hairs


28


, the plumber again finds that he has “nothing to grab onto” and is relegated to using a saw or hammer and chisel to carefully try to remove the tub shoe flange


24


without damaging the tub


20


, the tub shoe


16


, or the tub shoe fitting threads


18


. Often the plumber cannot avoid damaging the tub and may on occasion have to replace the whole tub at a great personal loss to either the customer and/or plumber.




A similar problem is presented when a plumber has to replace a lavatory sink drain flange


72


in a typical pop-up drain lavatory sink installation


70


(FIG.


2


.). Pop-up body


72


, nut


74


, and mack washer


76


are held against sink


75


from below while sink flange


78


is screwed into body


72


from above sink


75


and nut


74


is tightened. Stopper assembly


80


is inserted into body


72


from above the sink


75


and ball rod assembly is inserted into body


72


from below the sink


75


, while pop-up rod assembly


84


is inserted up and through the faucet housing (not shown) as is well known in the trade. When sink flange


78


is leaking, rusted, and/or corroded and needs to be replaced, it presents the same problem as the leaking, rusted and/or corroded tub shoe flange


24


discussed above, only in this case there are no cross hairs, the inside diameter of the sink flange


75


is too small to receive the typical castle of the dumbbell tool which cannot work in this application anyway since its side walls are smooth and slippery and not knurled. Thus, even if the plumber tries hammering the dumbbell or any similar tapered tool into the sink flange


78


opening


79


, the tool slips when turned and fails to unscrew the sink flange


78


from the body


72


. Again, the plumber is left to a hammer and chisel or hacksaw and the hope that he can remove the sink flange


75


without damaging the sink


75


.




Accordingly, there is a need for, and it is an object of the present invention to provide a plumber's tool that inserts into the flange drain hole, has moveable parts which can expand against and bite into the inside walls


25


of the flange drain hole, and then, by continued counterclockwise turning, easily and rapidly unscrew the flange from its fitting even in those occasions when the flange is rusted in place and there are no cross hairs.




b. Prior Tools With Expandable Shoes For Extracting Or Spreading




In one prior expandable extractor tool


90


(

FIG. 5

) having a body


92


with a rectangular shaped main portion


94


and a handle bar


98


through a top portion


96


also configured to receive a wrench, and a pair of moveable shoes


100


,


102


having internal rectangular inboard recesses


101


and multiple cylindrical shaped, knurled


104


, outside surface portions of varying diameter


106


,


108


,


110


,


112


,


114


resiliently held on the rectangular shaped spreader portion


94


by spring


116


with end


118


in hole


103


. The shoes may be removed and reversed to position diameter portions


106


,


108


at the lower end instead of diameter portions


110


,


112


by removing spring


116


, reversing the shoes


100


,


102


and replacing the spring


116


. In operation, the lower end of tool


90


inserted into, for example, the tub shoe flange drain hole


27


, and then while holding the outside knurled surfaces


106


,


108


,


110


,


112


,


114


with one hand so that they do not turn, the body portion


92


is rotated with the other hand thereby spinning the rectangular spreader portion


94


relative to the rectangular recesses


101


and spreading the shoes


100


,


102


against the bias of spring


116


until they engage the inside walls


25


of the tub shoe flange


24


, and then, by continued counterclockwise turning, unscrew the tube shoe flange


24


from its fitting


18


. There are many problems with this tool that prevent it from working in most cases.




1. It is very difficult to get the spreader portion


94


to spin inside of the shoes


100


,


102


against the compression of spring


116


.




2. It is extremely difficult to get a selected one the knurled


104


surfaces


106


,


108


,


110


,


112


,


114


to bite into the metal of the tub shoe flange


24


walls


25


except when there is a very good match of outside diameter of the shoes with the inside diameter of the flange walls such that the spreader


94


can get into a nearly orthogonal position relative to the shoes


100


,


102


in order to be in a position to get a good bite into the walls


25


of the opening without slipping. This is definitely a two handed operation.




3. A third hand is the needed to turn the tool using the bar


98


or a wrench.




4. Normally the plumber is not strong enough to get a bite into walls


25


with the bar


98


, and the tool slips in the opening


27


, espelally if the plumber is alone.




A second prior spreading tool (

FIG. 6

) is used to spread tail pipe end openings of automobiles. This tool has a large, heavy, round, steel body


122


having a top end shoulder


123


, a central bore


124


and a dome shaped interior cavity


126


and a notched bottom end


128


through which is disposed bolt assembly


130


having head


132


, shank


134


and threaded end


136


, carrying upper sleeve type spreader


138


with tapered walls


140


, middle positioning sleeve


142


, and owe spreader


144


with tapered walls


148


and interior threads


146


. Disposed around the bolt assembly are eight identical movable shoes


150


of which only two are shown in

FIG. 6

for simplicity. Each shoe


150


has a tapered upper interior notch


152


in a larger outside diameter portion


153


and a tapered lower interior end wall


154


in an outside reduced diameter portion


155


. Upper recessed notches


152


receive upper tapered spreader


138


and lower tapered end walls


154


receive lower tapered spreader


144


. Shoes


150


each have a pair of exterior annular recesses


156


,


158


into which are received retainer Wrings


160


,


162


which hold all 8 shoes resiliently in position when the tool is finally assembled.




In operation, reduced outside diameter portion


155


is inserted into an automobile tailpipe (not shown) and held in place with one hand while bolt head


134


is turned clockwise with a wrench with the other hand. As lower spreader


144


is drawn toward head


134


, the upper spreader


138


, positioning sleeve


142


and lower spreader


144


move as an assembly and spread the shoes


150


uniformly and evenly both at the top and at the bottom against the bias of retainer o-rings


160


,


162


. The tailpipe opening is spread and now tailpipes and muffler can be easily assembled s is known in the trade.




There are many problems with this tool as follows:




1. It is too large and too heavy for plumbing work.




2. It will not fit into the largest tub shoe flange openings.




3. The shoes cannot be spread by hand because too much force is required to turn the bolt.




4. The outside surfaces are not knurled and do not bite into the walls of the tailpipe.




Accordingly, there is a need for, and it is an object of the present invention to provide a small, sturdy, lightweight , plumber's tool that inserts into the flange drain hole, has moveable parts which can be easily expanded against the inside walls


25


of the flange drain hole with the hands and will remain in place by itself or can be held in place with one hand while the other hand is used to easily and rapidly spread the moveable parts to a hands tight position against walls


25


by initial turning of a nut, can then be easily made to bite sharply into the walls of a flange with a wrench by further turning of the nut, and can then easily unscrew the flange from its fitting by continued turning, even in those occasions when the flange is rusted in place and there are no cross hairs.




A third spreader tool


170


of the prior art (

FIGS. 7

,


8


) by Guillermo in U.S. Pat. No. 5,669,404 is used to lift the upper half of a diverter valve assembly from within a faucet. The tool


170


includes shaft


172


having threads


174


at one end and a frusto-conical wedge portion


176


at the other end, a split tab sleeve


178


having a bore diameter smaller than the frusto- conical wedge, projections


180


and a plurality of knurled


185


tabs


182


. Slide member is inserted over threaded end


174


of the shaft and abuts against projections


180


of sleeve


178


at the end opposite the tabs


182


and also overlaps the threaded end


174


of the shaft


172


. A nut


188


is threaded on to shaft


172


to meet washer


186


.




In operation, the split sleeve


178


end of the assembled tool


170


is inserted into the top half


192


of the diverter valve


190


, the nut


188


is turned clockwise


196


on threaded


174


shaft


172


driving slide member


184


down against projections


180


of sleeve


178


which is driven down against frusto-conical taper wedge


176


expanding tabs


182


against the inside walls of the upper half


192


of the diverter valve


190


. With the split sleeve


178


firmly in place, the entire tool


170


is then lifted with some force causing the upper half


192


of the diverter valve


190


to separate from the lower half


194


and allowing the upper half to be removed, cleaned and replaced without unscrewing the lower half of the diverter valve


194


from the threaded tube


198


secured therein from below by using a separate tool not relevant here.




There are many problems with this tool as follows:




1. The tool is merely used for lifting the upper half of a diverter valve which is snap fit together with its lower half and is easily separated therefrom.




2. The tool is not sturdy enough for use in an application to unscrew tub shoe flanges that are frozen or rusted together after years of use.




3. The knurled tabs weaken after continuous flexure and break off.




4. The nut is turned clockwise to expand the tabs. This is the wrong direction if the tool is to be used to unscrew a flange and only causes the flange to be tightened in its fitting which is counter productive.




5. The tool will loosen if the tightened nut is turned counterclockwise with a wrench to unscrew a flange since the unscrewing action requires a countercklckwise turn which is the same direction the bolt is turned to loosen the bolt.




Accordingly, as amply demonstrated above, there is a long felt and unfilled need for, and it is an object of the present invention to provide, a small, light, rugged plumber's tool that inserts into the flange drain hole, has expandable, resiliently biased shoes with knurled surfaces which can be easily expanded to a hands tight position against interior walls


25


of a flange drain hole by initial counterclockwise turning of a nut, can then be easily made to bite sharply into the walls of a flange with a wrench by further counterclockwise turning of the nut, and can then easily unscrew the flange from its fitting by continued counterclockwise turning, even in those occasions when the flange is rusted in place and there are no cross hairs.




BRIEF SUMMARY OF THE INVENTION




Set forth below is a brief summary of the invention which achieves the foregoing and other objects and provides the foregoing and hereafter stated benefits and advantages in accordance with the structure, function and results of the present invention as embodied and broadly described herein. Applicant's invention includes independently both the apparatus and the methods described herein which achieve the objects and benefits of the present invention. Both formats of the invention are described below, and it is applicant's intention to claim both formats even though from time to time below for purposes of clarity and brevity applicant will use either one or the other format to describe various aspects and features of the invention.




A first aspect of the invention is an extractor, or spreader, tool which includes a shaft having a frusto-conical wedge, or enlarged tapered portion, and left-handed threads, a plurality of segments, or shoes, resiliently retained around the threaded portion of the shaft, and a nut threaded on the threaded portion of the shaft for raising the frusto-conical wedge, or enlarged tapered portion, to expand the segments, or shoes.




A second aspect of the invention includes a method of making an extractor, or spreader, tool which includes the steps of providing a shaft having a frusto-conical wedge, or enlarged tapered portion, and left-handed threads, resiliently retaining a plurality of segments, or shoes, around the threaded portion of the shaft, and threading a nut on the threaded portion of the shaft for raising the frusto-conical wedge, or enlarged tapered portion, to expand the segments or shoes.




A third aspect of the invention is a method of removing a plumbing fixture flange which includes the steps of inserting an extraction tool having a plurality of separate radially expandable members resiliently maintained around a tool body into a drain opening of the flange, expanding the members into tight contact with an adjacent wall structure of the flange, and while holding the segments in the tight fitting expanded position, turning the tool counterclockwise to remove the flange.




Further features of all of the above aspects of the invention include the segments are arcuate shaped movable shoes, there are three segments which form substantially an expandable collar around the shaft the inside diameter of which is smaller than the diameter of the frusto-conical wedge, each segment having a central bore portion of uniform diameter for fitting cent the threaded portion of the shaft and a changing diameter portion smaller Fan the diametr of the frusto-conical portion of the shaft for fitting adjacent the frusto conical portion of the shaft, each segment being positioned around the shaft with its changing diameter portion nearest the frusto-conical portion of the shaft, each segment having a central bore portion of uniform diameter for fitting adjacent the threaded portion of the shaft between a changing diameter portion smaller than the diameter of the frusto-conical portion of the shaft at each end of the segment for alternatively fitting adjacent the frusto conical portion of the shafts, the outboard surfaces of each segment being knurled, a castle at the end of the shaft ad t the frusto-conical wedge, the shaft terminating at one end in a plurality of axially extending and radially aligned lugs., there being four lugs each 90 degrees apart, the outboard surfaces of the lugs tapered in a direction opposite the taper of the frusto-conical wedge, the outboard surfaces of the lugs being knurled, a central recess extending axially between the lugs, the central recess extending sufficiently to a to accommodate a long toe stop stem, the resilient retainer being an o-ring, and a washer between the nut and the segments.




Further features of this aspect of the invention are wherein the step of expanding the members into tight contact further comprises the stop of biting into the adjacent wall structure with a knurled outboard surface of the members,




Further features of the second through fifth aspects of the invention are the same as those set forth above for the first aspect of the invention which are hereby incorporated herein by reference.




The advantages of the invention are as follows:




1. The tool is small and lightweight, but also sturdy and rugged.




2. Enables extraction of a wide variety of frozen drain flanges in and out of the plumbing fields, including toe stop flanges with extra high centers.




3. Eliminates risk of damaging the tub, sink, or shower during extraction.




4. Works with or without cross hairs in the fixture to be removed.




5. Knurled surfaces allow extra torque for really stubborn, rusty flanges.




6. Removes frozen flanges rapidly.




7. Is easy to operate with two hands and tightens easily by hand-turning the nut.




8. Once tightened, just keep turning in the same direction with a wrench to remove the flange.




9. Inexpensive enough that every plumber can afford one.




10. Reversible shoes extend the life of the tool




11. Extra torque from knurled surfaces on castle lugs for use during extraction or installation of a new fixture




12. Tapered, longer castle lugs further increase utility for other applications where the cross hairs are deep.




13. Installs new tub shoe flanges easily by interlocking with the cross hairs.











BRIEF DESCRIPTION OF THE SEVERAL VIEWS DRAWINGS





FIG. 1

is an exploded perspective view in partial section of a typical tub shoe flange installation to which the present invention is applicable.





FIG. 2

is an exploded perspective view of a typical pop-up lavatory flange installation to which the present invention is applicable.





FIG. 3

is a perspective view of a first prior art “easy out” tool.





FIG. 4

is a perspective view of a second prior art “dumbbell” tool.





FIG. 5

is an exploded perspective view of a third prior art expandable extractor tool.





FIG. 6

is a partial perspective view of a fourth prior art automotive tailpipe spreader tool showing only two of eight expandable shoes for simplicity in presentation and understanding.





FIG. 7

is an exploded perspective view of a fifth prior art expandable diverter valve extractor tool.





FIG. 8

is a front elevation in partial section of the tool of

FIG. 7

being used to lift out the upper half of a diverter valve in a faucet.





FIG. 9

is an exploded perspective view of a first embodiment of the plumber's extractor tool of the present invention.





FIG. 10

is an exploded perspective view of a second embodiment of the plumber's extractor tool of the present invention.











DETAILED DESCRIPTION OF THE INVENTION




As seen in

FIG. 9

the extractor tool of the present invention includes a shaft


210


having left-handed thread


218


throughout most of its length terminating at one end in a flatted configuration


220


adapted to receive a wrench and having an outwardly extending frusto-conical or enlarged tapered shape


212


at the other end terminating in a plurality of axially extending lugs


214


, called the “castle” in the trade, surrounding a central recess


216


. Mounted on the shaft over the threaded area is a shoe assembly


230


having a central bore


238


and which includes, in the preferred embodiment, a plurality of three shoes or arcuate segments


232


,


234


,


236


retained together by resilient o-ring


244


received in annular groove


242


. Each shoe has a tapered recess


240


at its end nearest the frusto-conical end


212


of the shaft


210


but having an inside diameter less than the outside diameter of the frusto-conical section


212


. The tool


200


also includes a washer


246


and a nut


248


.




As seen in

FIG. 10

, a second embodiment of the present invention has features identical to the first embodiment which are identified by identical numbers. Additionally, this version of the invention includes knurling


252


on all of the shoe surfaces and shoes


232


,


234


,


236


are made reversible in that they bear a tapered recess


240


at each of their ends. This feature provides the added benefit of being able to reverse the shoes if the knurling


252


on one of the shoe surfaces gets damaged or wears out. The knurling


256


is also extended to the surfaces of the lugs


254


to give better gripping action during removal, if the cross hairs are present, and during installation when the lugs are placed between the cross hairs. The lugs


254


are made longer and the recess


258


is made considerably deeper to accommodate deeper cross hairs or longer toe stop stems, respectively.




Additional optional features include a second set of shoes to accommodate additional sizes of flange drain hole openings, stub outs, urinal/toilet spuds, copper pipe, and the like. The urinal and water closet (toilet) spud can be removed without an attachment. An additional plumbing attachment is contemplated for use in the removing cets from within faucet valves and provides stability while applying torque. An additional automotive attachment is contemplated for use in removing steering wheels and sizing tailpipes and mufflers.




The shaft is preferably made from hardened steel and coated with black oxide so that it will not rust. The shoes are preferably made from aluminum.




In operation, to remove a stubborn tub shoe flange


24


, for example, the castle end of the extractor tool


200


,


250


of the present invention is inserted into the drain hole


27


of the tub shoe flange


24


so that the castle lugs


216


enter the openings


31


between the cross hairs


28


and rest upon and engage the cross hairs


28


, if the cross hairs are present. If no cross hairs


28


are present, then the tool


200


,


250


is held in one hand in a position with the shoe assembly


230


, adjacent to the inside walls


25


of the tub shoe flange drain hole opening


27


. The nut


248


is then turned counterclockwise with the other hand to raise the frusto-conical wedge


212


into the shoe assembly


230


expanding the shoes


232


,


234


,


236


radially outward against the inner walls


25


of the tub shoe flange


24


drain hole


27


until a snug fit it obtained by hand. Then a wrench (not shown) is applied to the nut


248


and the counterclockwise turning is continued to both further tighten the grip and to unscrew the tub shoe flange


24


. If the cross hairs


28


are present, the tool can rest on the cross hairs with the lugs


214


,


254


, in the openings


31


, and the lugs


214


,


254


and knurled surfaces


256


thereon allow added torque to be applied to remove frozen or rusted flanges.




For installation, the tool


200


,


250


is inserted into the tub shoe flange


24


drain hole


27


resting on the cross hairs


28


with the lugs


214


,


254


in the openings


31


, the shaft is then turned clockwise with a wrench applied to the flatted top end


220


.




The foregoing description of a preferred embodiment and best mode of the invention known to applicant at the time of filing the application has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variation are possible in the light of the above teaching. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.



Claims
  • 1. An extractor tool comprising:a shaft having a frusto-conical wedge and left-handed threads, a plurality of segments resiliently retained around the threaded portion of the shaft, a nut threaded on the threaded portion of the shaft for raising the frusto-conical wedge to expand the segments, and a castle at the end of the shaft adjacent the frusto-conical wedge.
  • 2. An extractor tool comprising:a shaft having a frusto-conical wedge and left-handed threads, a plurality of segments resiliently retained around the threaded portion of the shaft, a nut threaded on the threaded portion of the shaft for raising the frusto-conical wedge to expand the segments, and a plurality of axially extending and radially aligned lugs at one end of the shaft.
  • 3. An extractor tool comprising:a shaft having a frusto-conical wedge and left-handed threads, a plurality of segments resiliently retained around the threaded portion of the shaft, a nut threaded on the threaded portion of the shaft for expanding the segments with the frusto-conical wedge, and turning the segments, and a castle at the end of the shaft adjacent the frusto-conical wedge.
  • 4. An extractor tool comprising:a shaft having a frusto-conical wedge and left-handed threads, a plurality of segments resiliently retained around the threaded portion of the shaft, and a nut threaded on the threaded portion of the shaft for expanding the segments with the frusto-conical wedge, and turning the segments, the shaft terminating at one end in a plurality of axially extending and radially aligned lugs.
  • 5. The tool of claim 4 further comprising four legs each ninety degrees apart.
  • 6. The tool of claim 4 wherein the lugs include outboard surfaces tapered in a direction opposite the taper of the frusto-conical wedge.
  • 7. The tool of claim 6 wherein the outboard surfaces of the lugs are knurled.
  • 8. The tool of claim 4 further comprising a central recess extending axially between the lugs.
  • 9. The tool of claim 8 wherein the central recess extends sufficiently to accommodate a long toe stop stem.
US Referenced Citations (13)
Number Name Date Kind
2380068 Patton Jul 1945 A
3579793 Williams et al. May 1971 A
3895652 Zach Jul 1975 A
3945276 Sorensen Mar 1976 A
4128930 Tomlinson Dec 1978 A
4460019 Condon Jul 1984 A
4529007 Goforth Jul 1985 A
5054179 Rini Oct 1991 A
5255435 Shultz Oct 1993 A
5363881 Larkin Nov 1994 A
5408732 Anfuso Apr 1995 A
5669404 Guillermo Sep 1997 A
5697459 Sher Dec 1997 A
Non-Patent Literature Citations (1)
Entry
Pasco Specialty & Mfg., Inc., The “Smart” Dumbell, www.pascospecialty.com web page, Copyright 1999, pp. 1-2.