Description of portable milling tool for milling tube or pipe ends to desired shape and thicknes

Spier, R. A.

English

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REPLY TO 
ATTN OF: GP 
TO : 
SUBJECT: 
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
WASHINGTON, D.C. 20546 
USI/Scientific & Technical Information Division 
Attentions Miss 
GP/Qffice of Assistant General 
Counsel for Patent Matters 
Announcement of NASA-Owned 
U-S, Patents in STAR 
In accordance with the procedures contained in the Code GP 
to Code US1 memorandum on this subject, dated June 8, 1970, 
the attached NASA-owned U , S ,  patent is being forwarded for 
abstracting and announcement in NASA STAR, 
The following information is provided; 
U , S ,  Patent No. 
Corporate Source 
Supplementary 
Corporate Source 
NASA Patent Case No,: -0 
Gayle Parker 
Enclosure:: 
copy of Patent 
NASA-HQ 
https://ntrs.nasa.gov/search.jsp?R=19710013323 2020-03-17T02:51:22+00:00Z
R. A. SPIER 
PORTABLE MILLING TOOL 
Tiled April 5, 1966 
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I G .  I 
INUEN TOR 
RAYMOND A. SPIER 
8 
Piled April 5,  1966 
R. A. SPIER 
PORTABLE MILLING TOOL 
FIG. 2 
RAYMOND A. SPIER I G .  4 
ATTORNEYS 
ite c 
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3,386,337 
P ~ ~ A ~ ~ E  MILLING TOOL 
Raymond A. Spier, Huntmilie, Ala., msigaor to the 
United States ef Ameka as cepresented by the 
Administrator of &e National Aeronautics and 
Space Administration 
Filed Apr. 5, 1966, Ser. No. 5411,414 
1 Claim. (C1. 90-12) 
CT OF THE DISCLOSURE 
A portable milling tool having an expandable mandrel 
which fits within the end of a tube and presses against 
the inside surface to round the end. The tool has a router 
revolving about the center of the mandrel to mill the end 
edge of the tube. 
The invention described herein was made by an em- 
ployee of the "United States Governmerit and may be 
manufactured and used by or for the Government for 
governmental purposes without the payment of any royal- 
ties thereon or therefor. 
This invention relates to a portable milling tool for 
milling tube or pipe ends to a desired shape and thickness. 
It is often necessary in butt welding t u b s  or pipes to 
reduce the thickness of the tube's edges so they may be 
welded together with best results. While portable machines 
have been developed to accomplish this purpose, they are 
unduly complex and often difficult to operate under field 
conditions. 
Some of the prior machines for example run on tracks 
secured to the exterior of the pipe and operate on the 
assumption that the pipe is perfectly round. 'If the pipe 
were out-of-round the depth of the edge cut would vary 
according to the distance the section af pipe being cut is 
from the fixed center about which the machine operates. 
Another type of m e is characterized by a support 
for rhe cutter which bears upon a small arc of a tube be- 
ing cut. The support ,of this type has rollers engaging the 
inner and outer walls of the tube for guiding the machine 
progressively about the tube. While this last type will have 
better results on out-of-round tubes than the type ranning 
on tracks secured to the exterior of the tube, the resultant 
tolerances and finish still often require further hand grind- 
ing operations. 
Accordingly, it is an object of the present invention to 
provide a tool of easily consaructed parts for milling tube 
ends and obtaining superior results than obtain herebefore. 
Another object is to provide a portable machine for 
accurately milling mt-of-round tube ends while still ob- 
taining close tolerances and a uniform finish. 
Other objects, features, and advantages of the present 
invention will become apparent as the description 
proceeds. 
The present invention Is capable of producing the de- 
sired profile on a tube end by utilization of a milling head 
support arm which is pivotally mounted on an expandable 
mandrel inserted in the tube end so as to rotate about the 
true center of the tube. The mandrel has a plurality of 
elements which are forced against the inner surface of the 
tube with sufficient force to  round the typical out-of-round 
tube. The milling head powers a cutter which cuts the tube 
end perpendicular to the tube's transverse axis, and the 
support arm guides the milling head and cutter concen- 
trically to the internal longitudinal center axis of the tube 
so as to maintain a uniform cut around the tube. The 
desired profile and end cut may be produced by one ro- 
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tation about the tube end or may be done in a series of 
cuts. 
This will be more readily understood by the following 
detailed description when taken together with the ac- 
companying drawings in which 
FIGURE 1 is a perspective view of a milling tool of 
the present invention 
F1GUR.E 2 is an ebvational cross-sectional view taken 
along h e  2-2 of FKXJXE 1, with portions shown whole 
for clarity; 
FIGURE 3 is a partial perspective view of the expand- 
able mandrel portion af the milling tool of FIGURE 1; 
and 
FIGURE 4 is transverse plan sectional view of the ex- 
pandable mandrel portion wiikhin a tube with parts re- 
moved for clarity. 
Referring now to the drawings and in particular to 
FIGURES 1 and 2 which shows the milling tool 11 af the 
present invention mounted on a tube or pipe end 13. 
The milling tool 11 is held partially within the end 
opening of the tube 13 by an expandable mandrel 15 as 
as shown best in FIGURE 2. The mandrel 15 as shown 
in FIGURES 2, 3, and 4 is composed of circular upper 
and lower plates 17 and 19 separated by six partitions 21 
which extend radially from the center axis of the plates 
17 and 19 to form six triangular compartments. A circular 
hole 23 is in the center of the upper plate 17 and a 
threaded circular hole 25 is in the center of the lower 
plate 19. The partitions 21 end a short distance outwardly 
from the center holes 23 and 25 so a passageway will in 
effect extend through the center of the mandrel 15. 
A plurality of substantially triangular or pie-shaped 
blocks 27 are inserted within the oompartments formed 
by the plates 17 and 19 and partitions 21. Each block 27 
has an apex surface 29 whiczl is complementary to the 
conical surface 31 of a cam eelement 33 which extends 
thFoagh the pawageway. The edge surface 35 of the blocks 
27 opposite the apex 29 is curved and the curvatnre is 
selected soits radius is equal to the internal radius of the 
tube to be milled. The curved eage surface 35 of the 
blocks 27 has a groove 37 therein whereby coiled springs 
39 may be wed to encircle the outer edge of the blocks 
27 within the groove 37 to prevent the blocks 27 from fall- 
ing out of their compartments as well as tending to urge 
them inwardly so their apex surface 35 will contact the 
conical surface 31 of the cam element 33, as illustrated in 
FIGURE 2. 
The cam element 33 is characterized by an upper cyl- 
indrical portion 41 and a lower conical portion 31 which 
slopes inwardly from the cylindrical portion 41. Extending 
axially from the cylindrical portion 41  is a bolt like shaft 
43 which has a screw thread along i ts lower circular part 
45 and Aat faces 47 along its upper part. A circular 
threaded shaft 49 'also extends axially downward from the 
conical portion 31. 
As shown in FIGURES 1 and 2, an elongated arm 51 
extends across the top surface of the upper mandrel plate 
15 and has one end cantilevered outwardly from that 
plate. The arm is characterized by having a hole 53 suib- 
stantially between its ends which has a diameter equal to 
the diameter of the center hole 23 of the upper plate 17. 
The cantilevered end of the arm 51 is enlarged and has a 
rather large hole 55 therein so as to have the .appearance 
of a ring. 
The cylindrical portion 41 of the cam element 33 is 
slidably received within the center hole 23 of the upper 
plate 17 as well as in the central hole 53 of the elongated 
arm 51. A nut 57 is screwed down on ,the threaded por- 
tion 45 of the upper shaft 43 lightly against the upper 
surface of the arm 51 so the arm 51 may rotate freely 
ed on a tube end; 
3,386,337 
about the cylindrical portio 41 of the cam element 33. 9 is positioned to a desired 
other nut 59 is screwed down on the threaded portion depth-the profile of the cut is determined by the shape 
of the shaft 43 so as to be tight against the first nut of the cutter 99-the plunger rod 79 is released. Also, 
57 to prevent it from moving. since the router shaft 97 will be rotating in a clockwise 
The lower threaded shaft 49 extending from the conical 5 direction and this reaction of the cutter 99 will tend to 
portion 31 of the cam element 33 is screwed into the rotate the elongated arm 51 in a clockwise direction, it 
center hole 25 of the lower plate 19. I t  should now be will also be necessary to press the raised end 6§ of the 
obvious that as the cam element 33 is screwed down into . stoD surina 63 into its recess 61 to allow the arm 58 to 
When the cutter eleme 
the lower plate 19, the conical portion 31 of the can1 
element 33 rotates against the complementary curved 
apex surfaces 29 of the block elements 27 so as to force 
them outwardly from their compartments. Also as the 
cam element 33 is screwed upwardly from the lower plate 
19, the coil springs 39 will force the blocks 27 inwardly 
against the retreating conical surface 3%. 
The top surface of the upper plate 17 as shown best 
in FIGURES 1 and 3 has a T-shaped groove 61 therein 
between the center hole 53 and outer edge. Within the 
main stem of the groove 61 a flat spring 63 is fastened 
which is raised upwardly sft a slight angle at one end 65 
so as to engage the edge of the elongated arm 51. The 
arm 51 may be released for movement in a clockwise 
direction by pressing the raised edge 65 into the groove 61. 
Another stop mechanism for the elongated arm is a 
plunger device 67 shown best in FIGURE 2. The plunger 
device 67 has two vertical legs 69, joined to the top sur- 
face of the elongated arm 51 which supports a cross 
member 71 having a vertical hole 73. The elongated arm 
51 also has a vertical hole 75 which is aligned with the 
hole 73 in the cross member 71, and the top surface of 
the upper plate 17 of the mandrel 15 has a circular recess 
77 which is also aligned with the other holes. A rod 79, 
with a handle 81 thereon at its top, extends through the 
cross member hole 73 and into the aligned hole 75 
within the elongated arm 51. The lower portion of the 
rod is smaller than the upper portion so a spring 83 may 
encircle the smaller rod portion and react between the 
large portion of the rod and the top surface of the elon- 
gated arm 17. The handle of the rod 81 may be pushed 
down so that the rod 79 will extend through the hole 7§ 
in the elongated arm 51 and into the recess 77 within 
the upper circular plates 17. If the handle is released, the 
spring 83 will automatically force the rod 79 upward 
from the recess 75 and into the arm 51 so the arm 51 
will be free to rotate. The recess hole 77 within the upper 
plate 17 and the spring 63 are located so both may func- 
tion at the normal start position of the elongated arm 51 
when the milling head 91 is started. 
As shown best in FIGURE 2, the milling head 91 is a 
typical power router 93 which is secured to the ring sur- 
face 95 of the enlarged and cantilevered arm end. The 
router’s shaft 97 extends parallel to the center of rotation 
of the arm 51 and places its cutter 99 into engagement 
with the tube edge. 
Operation 
In operation, the expandable mandrel 15 of the tool 
11 is positioned within the end opening of a tube or pipe 
13 to be milled. The operator using a wrench (not shown) 
upon the flat faces 47 of cam element 33 rotates the cam 
element 33 so it will be screwed downwardly into the 
center hole 25 of the lower plate 19. The conical portion 
31 of the cam element 33 thus engages the apex surfaces 
29 of the blocks 27 and forces the curved surfaces 35 
of the blocks 27 into engagement with the internal sur- 
face of the tube 13. The cam element 33 should be rotated 
so that sufficient force is exerted by the blocks 27 to 
round an out-of-round tube and tightly jam the mandrel 
15 within the tube. 
The power router 93 of the milling head 91 is started 
and its shaft 97 is adjusted by the conventional mecha- 
nism 98 on the router to place its cutter 99 in engagement 
with the tube rim in the desired manner. At the same 
time, the operator pushes the plunger rod 79 downwardly 
to lock within the recess 77 in the upper plate 17 so as to 
prevent any movement of the elongated arm 5 
rotke-in the desired manner. An operator needs to keep 
a firm hold on the handles of the router 93 to prevent it 
from running rapidly around the tube following the 
pressing of the raised end 65 of the stop spring 63 into 
its groove 61. 
After one revolution of the arm 51, the arm 51 is 
15 prevented from further movement by the stopping action 
of the raised edge 65 of the spring 63. If additional cuts 
of the tube edge is desired, the operation may be repeated. 
Obviously, many modifications and variations of the 
present invention are possible in light of the above teach- 
20 ings. It is, therefore, to be understood that within the 
scope of the appended claim the invention may be prac- 
ticed other than as specifically described. 
What is claimed is: 
1. A portable milling tool for milling tube ends, com- 
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rising: 
an expandable mandrel for gripping the internal sur- 
face of a tube to be milled adjacent the end opening 
thereof; 
a support arm pivotally mounted on said mandrel so 
as to rotate about the center axis of the tube to be 
milled and in a plane perpendicular thereto; 
a milling head having a power shaft with a cutter 
thereon supported on said arm adjacent one end 
thereof so its power shaft is parallel to the center 
axis of the tube to be milled and said cutter is adapted 
to mill the tube wall to a desired shape as said arm 
rotates; 
said mandrel having upper and lower circular plates 
with partitions therebetween extending radially from 
the center axis thereof so as to form a plurality of 
triangular shaped compartments; 
a hole within the center of the upper plate and a 
threaded hole within the center of the lower plate; 
said partitions ending outwardly of said holes whereby 
a passageway is formed through said plates; 
a plurality of substantially triangular shaped blocks, 
each block slidably fitted apex first within one of said 
compartments; 
the outer dege of said blocks opposite said apex being 
curved, 
a cam element extending through said passageway and 
adapted to force said blocks outwardly from said 
compartments and into contact with the inner surface 
of the tube to be milled; 
said cam element having an upper cylindrical portion 
and a lower conical portion which slopes inwardly 
from the cylindrical portion; 
a first threaded shaft extending axially upward from 
the cylindrical portion of the cam element; 
a second threaded shaft extending axially downward 
from the conical portion of the cam element; 
said support arm extending across the top surface 
of said upper plate and with one end cantilevered 
outwardly from the upper plate; 
said support arm having a first circular hole between 
its ends of a diameter equal to the center hole in 
upper plate and having its end which cantilevers out- 
wardly enlarged and with a second larger hole so as 
to form a ring surface which supports said milling 
head; 
said cylindrical portion of said cam element being slid- 
ably received within the center hole in the upper 
plate as well as in the similar first hole of said arm; 
said second threaded shaft of said cam element being 
screwed into the threaded hole of said lower plate; 
nut means on said first threaded shaft lightly contacting 
3,386,337 
eferences Cited 
5 
said arm so said arm i s  free to rotate about said 
to force the blocks outw&dly %om- their compart- 
ments in a uniform manner. LEONIDAS VLACHOS, Primary 


Portable milling tool Patent

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