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Sept» 10, 1946-
. .
Filed May _22, 1945
BY www
Patented Sept.v l0, 1946
Gerald J. Henjum, Hollywood, Calif., assîgnor of
one-third to Albert H. Farness, North Holly
wood, and one-third to Chester H. Sherer, Los
Angeles, Calif.
Application May 22, 1945, Serial No. 595,109
4 Claims. (Cl. 33-.-104)
This invention relates to a new and improved
The practical embodiment chosen for illustra
drafting instrument for developing flat patterns
tion comprises a draftsman’s triangle lil of con
of the‘intersection of surfaces of revolution such
as pipes used for ñuids, and standards or mount
ings wherein it is desired to develop a Wrap
arcund‘template or pattern to facilitate the cut
ting of the end of a pipe, as when it is desired
vto attach a branch pipe'v to another pipe at any
ventional outline, having the usual central open
ing Il whereby the inner edges of the side por
tions l2, I3 and i4 are parallel to the external
angle thereto.
, edges.
In addition, I have sho-Wn a protractor
arc l5 having suitable indicia, this feature being
useful in setting out the desired anglesat which
thepipes `are to be joined.
The coordinated series of scales as shown and
By well known mechanical drafting processes,
hereinbefore referred to, are grouped in vari
familiar to engineering draftsmen, it is possible
ous standard pipe sizes, which as is well known,
to develop such intersections and patterns or
are rated as the nominal inside diameters, vary
templates on the drawing board, with the use
ing in this case from one and one-quarter inches
of Yconventional drafting instruments. Such
processes are responsible for considerable delayV 15 to eight inches. In each standard size, I show
a scale Yiii marked ID (inside diameter) which
in'ñeld and shop work, where the Welder or sheet
metal worker desires to do the job on the spot.
It is, therefore, an object of this invention to
provide a layout instrument capable of use by
represents the successive projections on a diam
eter of arcs of twenty-two and. one-half degrees,
i. e., a semi-circle is divided into eight equal
a mechanic for developing such intersections as 20 parts, and the projections of these points on
the diameter form the scale. For convenience
needed, at a great saving of time as compared
I show only four points plus the center line l'!
to conventional mechanical drawing procedures.
for a ninety degree arc, as the other four points
The use of my herein described instrument elim
can be obtained by reversing the triangle and
inates the need of computations and the use of
conventional drafting instruments, as I provide 25 scale. A second scale I8, marked OD (outside
diameter) covers four points running the other
a »series of scales for each standard pipe size
to enable the workman to complete the develop
ment or layout of a wrap-around pattern or tem
way‘from the center line Il, and corresponds to
the actual outside diameter of standard pipe of
thenominal inside diameter specified. In order
plate, Which can be applied directly to the end
of ’the pipeto be cut'or beveled to lit against 30 to develop a flat pattern of the circumference of
a »pipe of given nominal size, I provide a third »
another pipe at the angle and/or offset contem
scale I9, marked X, which gives the actual de
plated. It is also sometimes convenient to de
veloped length of the arcuate segments divided
velop a wrap-around template to transfer the
as in producing the OD scale I8.
outline of the hole to be cut in the pipe to which
In order to be able to strike arcs correspond-'
the branch is to be applied, and this can read 35
ing to the actual outside diameters of the sev
ily be done with the instrument of my invention. `
eral nominal pipe sizes, I provide a series of per
With these and other objects in view, as will
more fully appear as the description proceeds,
forations 20, one oi’ which is marked as the center
drawing wherein:
O, and the others positioned at the correspond
my invention consists in the construction, novel
features and combination of scales hereinafterk 40 ing radii and marked for the nominal pipe sizes.
Inthe use of my layout instrument, the usual
more fully described, pointed out in the claims
mechanical drafting procedure is materially
appended, and illustrated in the accompanying
In the simplest case of a right an
gled joint between equal sized pipes, it is only
Figure 1 is a View of one side of a triangle
embodying the features of this invention; and, 45 necessary to draw two lines at forty-five degrees
and to carry the projections of the OD and ID
Figure 2 isa view of the other side thereof.
scales normal to one line to their intersection
While I have chosen to illustrate my inven
with the other lines, and measure their length
tion as incorporated in a triangle similar in out
on the forty-five degree line, transferring these
line to a conventional draftsman’s triangle, it is
to be understood that the exact proportions 50 lengths to ordinates erected at intervals deter
mined by the X scale to develop the layout or
and/or shape of the instrument is immaterial to
wrap-around template for cutting the ends of the
the principles of my invention, since my coordi
nated series of scales can be applied to other con
In a more complicated case of unequal pipe
figuratif-ns without affecting the usefulness
55 sizes, when the branch may be both offset and at
a specified angle to the main run of pipe, the
flexible sheet metal either for transfer direct to
procedure is a trifle more complicated, but still
the pipe, or as a template for contouring a collar
basically straightforward and readily apparent
to serve as a guide for cutting the ends of a numn
to those skilled in the art.
ber of pipes to the same pattern.
In order to determine
the ordinates to be applied to the layout or Wrap CTI
Obviously, my invention is susceptible of em
around template lines determined by the X scale
bodiment in forms other than that chosen for
for the branch pipe line, it is necessary to draw
illustration herein, and applicable to other and
a base line and strike an arc of the OD of the
analogous uses than pipe welding and/or assem
main run tangent thereto. The amount of off
bling, and I therefore do not desire to be limited
set is marked from the point of tangency and the 10 other than by the permissible scope of the claims
appended hereto.
ID and OD scales centered on the offset, the
scale markings being carried down to the arc pre
I claim:
viously marked, and then carried` out parallel to
the base line. The branch pipe center line is
drawn at the desired angle and the ID and OD
scales marked normal thereto,` being carried
down parallel to the center line ofthe branch
pipe to intersect the corresponding lines parallel
to the base line ñrst drawn. The lengths of thelines parallel to the center line of the branch pipe 20
form the ordinates of the developed or wraparound template.
I find it desirable to use the ID scales for the
“open” sides of the branch pipe, and the OD
scales for the “closed” sides of the pipes, since
by so doing the necessity of beveling the cut
ends of the pipe isy avoided, and in addition, a V is
left for the welding material, in the case of
standard pipe which has appreciable Wall thick
If working with thin-walled tubing or _
sheet metal, such as stove pipe, the outside di
ameter is also practically the nominal pipe size,
and both ninety degree arcs can be laid out from
the ID scales by reversing the triangle about the
center line of the scale. However, the illustrated
embodiment of the developed length scale I9
allows for appreciable pipe thickness, so that for
thin metal the spacings of the flat pattern should
be reduced in proportion to the difference be
tween the circumference of standard pipe and
the desired circumference of the tubing, by set
ting the scale at an angle to the base line suffi
cient to reduce the spacings the required amount.
In the use of the instrument of my invention,
the development or wrap-around template may
be drawn on any convenient material.
If only a
single joint is to be made, it may be drawn on
paper, which is subsequently wrapped around the
pipe and the outline transferred thereto as by
prick punching. If a number of duplicate joints
are to be made, the template may be drawn on
_1. A layout instrument embodying a polygonal
sheetmaterial having a plurality of scales dis
posed along the edges thereof, comprising base
line projections of equally divided circular arcs
corresponding to the inside and outside diame
ters of a plurality of standard pipe sizes, to
gether with scaies of the developed circumference
of similar pipe sizes divided into units corre
sponding to the spacings of said circular arcs.
2. An instrument adapted to develop the in
tersections of surfaces of revolution, embodying
a member having at least one straight edge, a
series of coextensive indicia for at least one circle
of a desired diameter marked on said straight
edge, comprising a scale of Vbase line projections
of _uniform divisions of an arc of said circle, and
a second scale of the developed lengths of said
arcuate divisions.
3. A drafting instrument comprising a plane
figure having a plurality of straight edges, and
coordinated series of scales marked thereon for
a plurality of standard pipe sizes, each set of
scales for a >particular pipe size including scales
of projections of equal arcuate divisions of cir
cles corresponding to the inside and outside di
ameters of the particular pipe size, and a scale
of the developed length of the arcuate divisions
of the outside diameter of said pipe size.
4. A layout instrument comprising a triangle
having self-contained means for developing the
intersection of surfaces of revolution, said means
comprising a plurality of scales of base line pro
jections _of a plurality of arcuate curves of vari
ous radii divided into equal segments, and cor
responding scales of the developed length of such
arcuate segments for each radius of said ñrst
mentioned scales.
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