4,025,749
1 2
that roll section is fixed with respect to sleeve 18. The
APPARATUS FOR MAKING BUTT-WELDED upper section 32 is secured to sleeve 18 by a key 38.
TUBES Keyway 40 in roll section 32 is longer than key 38 so
This invention relates to apparatus for making butt- that roll section 32 can move axially while rotating with
welded tubes utilizing welding rolls and more particu- 5 shaft 6. A pressure nut 42 is threaded on upper
larly to making such tubes with a substantially smooth threaded portion 44 of sleeve 18 with its bottom abut
inner seam. It is common practice to make butt-welded ting the top of roll section 32. In one roll the threads
tubes from rolled strip or skelp particularly steel and wm be right hand and in the other, left hand. A pair of
stainless steel strip. The strip is bent in a horizontal mill tapped holes 43 are provided through the wall of nut 42
into tubular shape and then with its longitudinal edges 10 for receiving set screws 43S. A tube 46 is received in a
close together the strip is passed through grooved weld- groove in nut 42 and is provided with scale markings 48
ing rolls mounted on vertical axes. Mills of this general to indicate the vertical position of the nut. The scale
type are shown in the patent to Morris U.S. Pat. No. markings 48 are preferably graduated in thousands of
3,691,337 dated Sept. 12, 1972, but the invention may an inch and a scribe line 49 is made on ron section 32.
be used with any tube welding rolls. 15 Holes 50 are provided in nut 46 for ease of rotation by
One problem involved in this type of mill is to have means of a tooL when assembled the scribe line 49
proper alignment of the strip edges during welding. The indicates the zero position when the wall thickness is
problem is magnified by the fact that rolled strip is uniform. A seal 52 is provided at the top of nut 46. A
seldom of the same thickness across its entire width. substantially semi-circular peripheral groove 54 is pro
Thus it is common for one edge of the strip to be 20 vided in the outer surface of the assembled roll sections
thicker than the other edge. with substantially equal portions in each section. Roll
Prior to our invention it was common practice to sections 30 and 32 haye d eri heral rooves 56
remove the one-piece weld rolls from the weld roll and 58 res ectivei in their inner surface for receiving
block and add shims as required so that when the weld compression springs 60. Upper and lower shoulders are
rolls were installed the tube edges aligned properly. 25 provided by the grooves against which the springs bear.
This procedure is time consuming and requires a cer- ff ... >m *er rf £ fee ^ in6
tain amount of guess work to determine the exact „. , . . . r ,A .J ■ ., °. ,
. ,. 6 . , , ,,,, ,. . . 58 in lower retaining ring 64 having upwardly extend
amount of shimming needed. When dimensional e u u A A ■
, , , lL. ,6 ,, „ , ^ ing pins 66, one for each spring may be provided in
changes m skelp thickness occur the weld rolls have to «• 1 1 A- ■
... > . r,. ., , . , e. ...» 1 „„ groove 56. In one particular embodiment 24 springs are
be shimmed to align the skelp edges. Since the internal 30 6 ... u n^i ■• 1 . *o r
. °cc . |. j J i- j provided in each roll. Tool receiving slots 68 are pref
seam edges were offset, the aligned edges were aligned Ki ^ • 1 1«
by gaging the OD of the tubing to be flush and allowing ,y ma . m s'eeve 18'
the edge dimension variance to be internal. As a result .In operation, the pressure nut 42 is rotated to posi
the internal scarfing tool tended to be unstable and not tlon " m des'red locatlon- Th,s ls donf bv ,ns0ertlng
operate properly so that many tubes were rejected. In 35 atoo1 mt0oneofthes'ots68*'Preventsleeve 18from
many cases, the formed tube shape leaving the last fin turmnS and turning Ac nut 42 by a spanner wrench
pass was not the shape of the weld rolls. inserted intoJ °.ne °[ f hoIes Set scre,ws 43S are
It is therefore an object of our invention to provide *en s,crewed into holes 43 and a8a,nst sleeve 18 to
welding rolls which will confine the bent strip in such a hold nut 42 ln des,red position. The upper roll
manner that either the internal seam or external seam 40 sectlon 32 18 b,ased uPwardly by springs 60 against the
edges are not offset. nut 42 w'th back lash being negligent. Gap G between
Another object is to provide such apparatus in which the roll sections in one particular embodiment may
the rolls may be adjusted without removal. varv between 0 and 0.030 inches. With the strip edge
These and other objects and features ofthe invention thickness being equal each roll is adjusted to the same
will become apparent from the following detailed de- 45 zero position. If edge El is thicker than edge E2 as
scription taken in connection with the accompanying shown in FIG- l> the pressure nut of roll 4 is adjusted
drawings in which: downwardly until the bottom of the edges are in align
FIG. 1 is an elevation, partly in section, of the rolls of ment It will be seen that if edge E2 is thicker than edge
our invention; and El the upper section of roll 2 will be lowered.
FIG. 2 is a top plan view of one roll. 50 lt wi" be seen that the rolls may be adjusted in the
Referring more particularly to the drawings refer- opposite direction if it is desired to align the top of the
ence numerals 2 and 4 indicate a pair of weld rolls for edges rather than the bottom.
receiving a bent strip or skelp S. Since the rolls are Instead of both rolls being split, only one may be split substantially the same only roll 2 will be described in and adjustable, but this limits the amount of control, detail. The roll 2 includes a vertical stationary shaft or 55 While one embodiment has been shown and despindle 6 mounted in base 8. Surrounding the shaft 6 scribed, it will be readily apparent to those skilled in are antifriction bearings 10, each having an inner race the art that various adaptations and modifications may 12 and outer race 14 with rollers 16 therebetween. A be made within the scope of the invention, sleeve 18 surrounding the bearings 10 has an inner We claim:
flange 20 extending into the space between bearings 10 60 1. Apparatus for confining an elongated strip bent
and a lower flange 22 extending outwardly. A ring 24 into tubular shape with its longitudinal edge separated
surrounding the shaft 6 at its upper end holds the bear- to form a slot therebetween comprising a pair or rolls
ings 10 in place. Oil seals 26 above and below bearings each having a peripheral groove therein for receiving
10 provide a sealed oil chamber 28 for the bearings. substantially half of said bent strip with its slot adjacent
The roll proper is divided into lower section 30 and 65 the outer pheriphery of said groove; at least one of said
upper section 32. The lower section 30 is fastened to rolls including a shaft, a pair of roll sections each in
sleeve 18 by means of cap screws 34 passing through eluding a portion of said peripheral groove mounted on
flange 22 into threaed holes 36 in role section 30 so said shaft, resilient means biasing said roll sections
