US 2743521 A
Description (OCR text may contain errors)
May 1 1956 w. F. OBERHUBER ETAL 2743521 RADIALLY CUTTING TUBE CUTTER HAVING ADJUSTABLE TOOL filed July 29, 1955 2 sheets-sheet 1 5.5i? i7 25 3 3/ ,ya e.;
May 1, 1956 w. F. OBERHUBER ET AL. 2,743,521
RADIALLY CUTTING TUBE CUTTER HAVING ADJUSTABLE TOOL 2,743,521 zR'lIiIJIIY CUTTING TUBE 'CUTTER HAV ING -DJUSTABLE TOOL i `William F. "berhliber fand .Erne'st Wollim Philadelphia, 'and lfredfl. Goetz'e, *Huntingdon Valley, Pa. fApplcationJuly 29, 1953, Serial No. 370,972 2'ClaimS. (Cl. 30-8-106) "The Apresent invention 'relates AIto `cutters `for condenser, "co'o'ler and heatexchangertubes. Apurpose o'fthe invention is Vto obtain more 'positive action and particularly to obtain v'rnorepositive release 'of the cutter y"from the "tube after cutting.
A f'fu'rt'he'r purpose is to make a lighter, smaller 'and simpler tbercu'tter.
`Affurtherpurposeis to speed up the cutting action and iappear, selecting -t'helforms shown from 'the standpints-of :convenience iniillustrati'on, satisfactory operation andclear I*demonstrationrof'the .principles involved.
Figure '.liis aflongitudinaltsectionfofithe preferred cutter ."of the :invention 1in fretraete'd position.
Figure 2 is a view corresponding to Figure l showing 'the cutter'adv'anced to'cutting position.
fFigure 'B isa :longitudinal Vsection Ion the line 3 3 'of iEigLlIefl.
- Fi'guref'4sis :a freary endelevaton' of thedevice ofFigu'res Figure .5 is a staggered rsection 4on 'the 4line "5v-'5 vvof .Figure 1.
Y fFigurefis section onsthelinedotzFigure 1.
:Figures 7 to .14 showavariationfinthe invention.
:Figure .7 -.is a tlongitudinal :section showing .fthe :cutter .'installed, :readyfto `cut a-tube,:but\sti1l retracted.
Figure 8 .is :a view corresponding to Figure .7 showing .thecutter/advancedandthe'tubecut.
Figure 9 lisa Vsectionon the line --9=9 of Figure 7, omit- .tingfthetubeandtubesheet.
4Figure .l-O vis yan enlarged front -view1of-1th`e `cutter'fof `Figures v7 'to 9.
HFigure 1-1 .is1an enlargedsection on '.theli'ne 11-1=1 of -F-igt 7., omitting lthe tube. f f
Figure 12 is an enlarged-section on the :line 12-12iof Figure 7. y
Figure 13 is anenlarged section on the line 13-13 of "Figure 7.
Figure 14 is a fragmentary section on the line 1'4--14 of Figure 1l. p
Describing in yillustrationbut n'tin liinitation'and referring to the drawings:
Tubes in condensers, coolers and other heatexchangers 'are usuallyrolled'into -engagement with-a tubesheet, and
"they'canbeveryquickly installed. It is, however, occasionallynecessary to remove-and replace such'tubes and` this isla diiicultl operation. In 'commonpractice in removin'g the tube, itfiscut vbyfa-tube cutter which cutsotf `the tube .inside fthe -tube .sheet and thus pe'rmits "the fs'evered ,United States patent@ patent `have several disadvantages.
Pa-tented .May l, .1.956
2 is-an improvement over `tube cuttersof the type disclosed in William F. Oberhuber U. S. :Patent No. 1,922,630, ,grantedAugust .15, 1.933,.'for Cutter'for Condenser Tubes.
Cutters -of Athe-character of thatf shown in the Oberhuber Once `the tube is cut thecutter is often `slow inrestoringthe Yparts-to1starting positiomso that Atherefis delay or -diieultyin Lextracting the cutting edges. By-thetpresent inventionamore rapid .positive .carn action is lapplied to return the cutter to its startingposition to avoid ythis difficulty. n
In the .prior artl cutters, Athe operation has often .been slow, because `the feed of ithe cutter -has not lbeensuillciently rapid. The ,present .invention is designed :to `rgive more rapid -feed andpreferably :to employa cutter .separate from the cutter bar which .is 'extending .radially -and can be positioned at `the most advantageous :angle .for maximum xfeed. 5 The device of the invention also is ymarkedly llighter -and 'smaller than prior art cutters.
One of the :features Whichfhas lbeen inherent in prior art cutters is 'that a great deal of strength-and energy has been required'in operation. `Part ofthishas'been due to -thefri`eti`o`nal drag ofthe collar against-the end of the tube. 'In 'thedevi'ce 'of vthe invention this has been cutdownby .introducing an a'ntifriction thrust bearing at this point.
"In '.'some cases obstructions on the inside of '.the'tibe 'mfake "it necessary 'to 'ream as 'a .separate operation. lIn "one 4ofthelfon'ns of"th'eimfention:a reame'r is mounted 'on "the forward endof 'the 'cutter so thatfany--sur'faces requirvving rea'mi'ngwill be Jreame'd as the'cutter is introduced 'irito the tube.
"Considering, now 'the form 'of Figures "l Lto f6 inclusive, aplug 20 "which formsthe main body df "the device Jhas a -forwajrd=portion 21 which extendsinto the nibet'ojbe cutan'dis suitably of the'large'st diameter of the plug, has a'ntintermediate 'portion '2'2"whic`h .is suitably of circular outside contour and'is o'fsrlig'htlyLrleduced diameter, ,jo'ining Ythe -forward portion "21 :in a stop shoulder 23, and has a rearward shank 24 which is adaptedtobe chucked 40 ina'rotary drill 'or'oth'er rotary tool operates .the
From'a"position1just"forw'ardof the shank 24, a longitudinal slot Jz'sextenusthe full distanceforwardto the front y'olf the 'cutterand is "ad'aptedito contain `the cutter `bar.
Surrounding'theplug andnor'mally engaging the shoul- `der '24 is a washer-like forward thrust bearing race .26 which is movable along "the .plug as shown. Rearwardly ofthe lforward thrust "bearing race 26 and providing .a rearward thrust bearing "race we place a collar 27 which "moves longitudinally of the plug in operation. To complete the thrust bearing, balls 28 are placed Abetween the 'forwardrace and the collar. The balls lZ8 are heldin place `by aconventional vball retainer "ring '.(not illustrated).
Thecollar is desirably provided with an annular ex- 'ten'sion i3'() directed rearwardly and this vengages the `for- 'ward'end of laspiral compression vspring 31, the rearward en'd df which isengaged by a vspring abutment 32 which surrounds the plug and is adjustable along f'it .by a set k'scre'w 33. Thusthe'spring tension can be regulated.
`In 5ltheslot y25 'and extending 'forwardly of the collar v'the'reii'sa tool bar 34 which at"it`s"for'w'a'rd end hasa transverse-'opening 35 which receives a vtransverse radially exvtending'cutter 36, :held in "place by set screw-37 which .in
fthe lform of Figures l'to 6 extends longitudinally. As
vshown in Figures 3`t`o 6, the slot^25 is desirably positioned to one side of the center so that the leading edge of the fcutter`36-is radial.
'The cutter'har nearits rearward end has a pivot ear 38 which extendsinto a 'slot 40 df the collar. A pin 41 extends acrossthecollar 'through an 'opening therein to pivot 4the lcutter-iban In the retracted position, one face 42 of the cutter bar extends longitudinally along the base of the slot, but near the forward end behind the cutter a cam portion 43 of the cutter bar deviates from the longitudinal line of the face 42 in a direction away from the cutter point, forming a cam surface which on rearward movement of the collar engages a cam surface 44 on the forward end of the slot in the plug to urge the cutter radially outwardly as shown in Figure 2. Rearwardly of the pivot 41 the cutter bar has a cam extension 45 which on the surface 46 extends convergingly toward the bottom of the slot as it moves rearwardly. Pin 47 extends across the plug near the base of the slot and when the cutter retracts the cam surface 46 on the cam extension 45, engages the pin and forces the cutter radially inwardly. This therefore gives very effective retraction of the cutter. The collar 27 is slotted at 47 to permit insertion of the pin 47.
In operation of the form of Figures 1 to 6, with the parts in retracted position and the shank mounted in the chuck of a drill, the forward portion 21 of the plug and the cutter and the forward part of the cutter bar are inserted in the tube to be cut. When pressure is applied with rotation after starting the electric drill or other tool, the thrust bearing race 26 engages the end of the tube and the thrust bearing permits rotation of the cutter without serious frictional drag since the friction is reduced by the bearing balls 28. As the collar moves rearwardly in Figure 2 the engagement between the cam surfaces 43 on the cutter bar and 44 on the plug urge the cutter radially outwardly, and the tube is cut. When the cutting operation is complete the operator releases the pressure and allows the spring 31 to force the collar forward. At this time pin 47 encounters cam surface 46 and positively forces the cutter bar to the retracted position.
In the above operation, very rapid feeding is accomplished and this can be done without damage to the cutter since the cutter is directed radially outwardly and is not merely inclined. Comparatively little strength is required because the drag previously experienced between the collar and the end of the tube is largely avoided.
The forward race 26 of the thrust bearing need not turn and ordinarily will not.
In the form of Figures 7 to 14 a reamer is provided toc ream any burrs in the same operation, and the reamer is used as one of the cam surfaces to retract the cutter bar. As seen in Figure 7, a tube 48 to be cut extends through a tube sheet 50 and has been rolled at 51 to eugage the tube sheet and anged at 52 at the outer end.
In this form the plug has a forward portion which is of reduced diameter at 53, and receives a tubular reamer 54 which makes a forced t and has outer tinted portion 55. At a position still inside the tube during cutting, the forward portion of the plug is enlarged at 56 to form the stop shoulder 23. The thrust bearing including the collar, the spring abutment and the spring are suitably the same as in the other form. The slot extending longitudinally through the plug in this form involves a straight slot portion 57 which extends to a position near thc tool, then a tool feeding cam 58 and then a recess 60 toward the forward end which allows the tool to move inward.
The tool bar in this form is straight for a considerable distance forward of the ear 38, but forward of the tool receiving opening which mounts the radially extending tool 36 there is on the outside a retraction cam 61 which during the retraction engages the inner edge 62 of the reamer. The set screw 37 which holds the tool in this case extends in from the side of the tool bar instead of outside near the forward end of the tool bar engages the inside of the reamer at 62 to retract the tool. The reamer functions during the early stages of cutting to remove any burrs and allow the cutter to achieve the required position in the tube.
In view of our invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of our invention without copying the structure shown, and we therefore, claim all such insofar as they fall within the reasonable spirit and scope of our claims.
Having thus described our invention what we claim as new and desire to secure by Letters Patent is:
l. In a cutter for tubes, a plug having a longitudinal slot, adapted to extend into a tube to be cut, having near its forward end an external shoulder directed rearwardly and having a shank at the rear adapted to be received into the chuck of a rotary tool, a forward thrust bearing race surrounding the plug and normally engaging the shoulder, a collar surrounding the plug rearwardly of the forward thrust bearing race and forming a rearward thrust bearing race, thrust bearing elements between the forward thrust bearing race and the collar, the collar, forward thrust bearing race and thrust bearing elements being movable along the plug, a spring abutment adjustably secured to the plug rearwardly of the collar, a spiral compression spring surrounding the plug and acting be tween the spring abutment and the collar, a tool bar extending longitudinally through the slot and having a tool mounting at its forward end, a tool secured in the tool mounting and extending radially, a pivot on the collar pivotally mounting the tool bar, cam means at the forward end of the plug acting between the plug and the tool bar to urge the tool bar outwardly when the collar moves rearwardly, a cam extension on the tool bar rearwardly of the pivot, and a pin extending across the slot secured to the plug and acting against the cam extension to urge the tool radially inwardly when the collar moves forward.
2. In a cutter for tubes, a plug having a longitudinal slot, adapted to extend into a tube to be cut, having near its forward end an external shoulder directed rearwardly and having a shank at the rear adapted to be received into the chuck of a rotary tool, a forward thrust bearing race surrounding the plug and normally engaging the shoulder, a collar surrounding the plug rearwardly of the forward thrust bearing race and forming a rearward thrust bearing race, thrust bearing elements between the forward thrust bearing race and the collar, the collar, forward thrust bearing race and thrust bearing elements being movable along the plug, a spring abutment on the plug rearwardly of the collar, a spiral compression spring surrounding the plug and acting between the spring abutment and the collar, a tool bar extending longitudinally through the slot and having a tool mounting at its forward end, a tool secured to the tool mounting and extending radially, a pivot on the collar pivotally mounting the tool bar, and cam means acting between the plug and toolbar to move the tool radially outward in one direction of relative movement of the plug and tool bar, and to move the tool radially inward on the opposite direction of relative motion.
References Cited inthe le of this patent UNITED STATES PATENTS 646,907 Henrikson Apr. 3, 1900 794,337 Blevins July l1, 1905 872,290 Lusk Nov. 26, 1907 1,922,630 Oberhuber Aug. l5, 1933 2,262,041 Pennella e Nov. 11, 1941 2,356,402 Haynes Aug. 22, 1944 2,446,734 Armstrong Aug. 10, 1948