Method of forming a metalic intermediate quasi-half annuli, useful in association with forming a full annulus about insulated pipes and related equipment

The invention provides for an intermediately formed quasi-half metallic annulus useful in constructing a full metallic annulus that can be mounted at the ends of insulated pipes and like equipment for weatherproofing purposes. Each quasi-half annulus includes (a) an arcuate side wall defined by a common radius originating along a longitudinal line of formation parallel to the side wall, (b) an end wall connected at one end of the side wall, (c) the side and end wall including an integrally formed corner for uniting them wherein the side wall has a rectangular opening parallel to the line of formation and an arcuate opening normal to the line of formation at an end opposite to the end wall. The rectangular opening is offset to a side of the line of formation in a direction opposite to the position of the side wall so that the combined area of the side and end walls is slightly greater that a conventional half annulus of similar shape and dimensions. Due to the invention, the side and/or end openings are also flexibly workable to permit entry within or without mating side and/or end openings of an another intermediate quasi-half annulus of similar construction. Result: a full annulus united along a U-shaped overlap region of common transverse and circumferential length W is easily formed, say for covering over an open side of insulation about pipes and associated equipment to protect same. A method of formation and usage is also described.

The present invention relates to intermediate formed, quasi-half annuli and 
formation method therefor useful in constructing a full annulus thereof 
and more particularly to such quasi-half annuli each having an integral 
arcuate curved corner between its end and side wall that results from a 
stamping operation that first cuts and then folds the blank material 
relative to the corner, say during a single active stroke of a punch plate 
relative to a die plate of a stamping machine. After the return stroke of 
the punch plate has opened the fixture, the completed quasi-half annulus 
is cleared from the fixture and the process repeated. That is to say, the 
combination of active and return strokes of the punch plate provides for 
formation of the quasi-half annulus of the invention from a blank of 
metal. After at least a pair of quasi-half annuli have been manufactured, 
easy assembly thereof to form the completed metallic full annulus, can 
easily occur at the work site usually at the end of insulated pipe of a 
piping assembly or the like. That is, each such full annulus is composed 
of a pair of quasi-half annuli united along a longitudinal plane through 
the completed annulus, such plane intersecting the longitudinal axis of 
symmetry as well as bisecting the end and side wall thereof. 
DEFINITION 
In this application, the term "quasi-half annulus" refers to 3-dimensional 
figure that includes an arcuate side wall defined by a common radius 
originating along a common longitudinal line of formation parallel to the 
side wall, an end wall connected to the side wall intersecting the line of 
formation, and an integrally formed corner uniting the end wall and side 
wall wherein the side wall defines a rectangular opening parallel to the 
line of formation and an arcuate opening normal to the line of formation 
at an end opposite to the end wall. The rectangular opening is offset to 
one side of the line of formation in a direction opposite to the side wall 
so that the area of the side wall and end wall is slightly greater that a 
conventional half annulus having a semi-circular, end wall but being open 
at the other end. 
BACKGROUND OF THE INVENTION 
In order to conserve energy, Federal and State commercial and residential 
codes and regulations specify efficiency standards, included in these 
standards for piping, duct and associated equipment are insulation 
efficiency values. Insulation type, dimensions, hardware etc., can be 
specified. In addition, there is a need to protect all end edges of the 
insulation circumferentially projecting around such piping and associated 
equipment, usually by metallic caps. 
As far as I am aware, most metallic caps for use in the aforementioned 
applications, are individually crafted, by conventional cutting, rolling 
and crimping techniques. While there has been some attempt to use factory 
fabrication methods, experience has shown that the side wall and top wall 
of such caps are still individually constructed in sequence and then 
united along full circumferential connection equi-spaced from the 
longitudinal axis of symmetry thereof, viz., to the circumferential 
extending termini of the top and side wall. Because of haphazard 
dimensional restrictions, there is required a doubled wall-overlap 
crimping arrangement ("Pittsburgh Seam") to unit the walls. Thus, such 
caps are expensive and because of dimensional instability, are subject to 
a need to continually retrofit the finished caps until a good fit occurs 
at the work site, all costly and time consuming operations. 
SUMMARY OF THE INVENTION 
The invention provides for an intermediately formed quasi-half metallic 
annulus useful in constructing a full metallic annulus that can be mounted 
at the ends of insulated pipes and like equipment for weatherproofing 
purposes. Each quasi-half annulus includes (a) an arcuate side wall 
defined by a common radius originating along a longitudinal line of 
formation parallel to the side wall, (b) an end wall connected at one end 
of the side wall, (c) the side and end wall including an integrally formed 
corner for uniting them wherein the side wall has a rectangular opening 
parallel to the lien of formation and an arcuate opening normal to the 
line of formation at an end opposite to the end wall. The rectangular 
opening is offset to a side of the line of formation in a direction 
opposite to the position of the side wall so that the combined area of the 
side and end walls is slightly greater that a conventional half annulus of 
similar shape and dimensions. Due to the invention, the side and/or end 
openings are also flexibly workable to permit entry within or without 
mating side and/or end openings of an another intermediate quasi-half 
annulus of similar construction. (This feature of the invention is called 
a "bisexual" attribute since either one of the pair of quasi-half annulus 
can be a "male" member or a "female" member after attachment occurs.) 
Result: a full annulus united along a U-shaped overlap region of common 
transverse and circumferential length W is easily formed at a work site, 
say for covering over an open side of insulation layered about pipes and 
associated equipment to protect same against fluid intrusion. A method of 
formation and usage is also described.

DETAILED DESCRIPTION OF THE INVENTION 
As shown in FIGS. 1-3, a pipe stub 10 is attached to a pipe end 11 of a 
pipe 12. The stub 10 includes a side wall 13 having an inner surface 14, 
and outer surface 15 and a end wall 16 normal to longitudinal axis of 
symmetry 17. Opposite to end wall 16 is a series of threads 18 at the 
inner surface 14 of the stub 10. The threads 18 engage like-threads 19 at 
exterior surface 20 of pipe 12. The pipe 12 includes side wall 22 defining 
an axis of symmetry coincident with the axis of symmetry 17 of the pipe 
stub 10. 
Insulation 25 is rectangular in cross section and has an inner broad 
surface 26 that is rolled about the pipe stub 10 and the pipe 12 and then 
secured to pipe stub 10 and the pipe 12, respectively, via a jacket 27. 
Thus, the insulation 25 takes the shape of pipe stub 10 and the pipe 12, 
i.e. cylindrical. Side surface 28 of the insulation 25 is then trimmed in 
a plane normal through the axis of symmetry 17 of the pipe stub 10 
parallel to the end wall 16 to which is secured a full metallic annulus 30 
formed in accordance with the invention, such attachment being via say a 
series of fasteners one of which is shown at 81. 
Metallic annulus 30 is composed of a pair of quasi-half annuli 31, 32 
matched in shape at formation but united in use, along a flexibly U-shaped 
overlap region 35 (in cross section) bisected by a longitudinal plane P, 
such plane P being coincident with the longitudinal axis of symmetry 17 as 
well as bisecting combined end wall 33 and combined side wall 34 of the 
full annulus 30. The flexible U-shaped overlap region 35 has a parameter 
Po approximately equal to 2 H+2 R where H is the height of the side wall 
33 and R is the outside radius of the side wall 34. 
Note in FIG. 3 that the overlap region 35 includes identically shaped 
raised punch marks or dots 36 coincident with the axis of symmetry 17. 
This allows easy assembly as described in more detail below. 
FIGS. 4-10 show the quasi-half annuli 31, 32 that comprise the full annulus 
30, in more detail. Since the quasi-half annuli 31, 32 are the same, a 
description of one fits the other. Hence, although the description below 
related specifically to annuli 31, note that the same is equally relevant 
and applicable to annuli 32. 
As shown the quasi-half annuli 31 includes an arcuate side wall 34a defined 
by a common radius R originating along longitudinal line of formation 38. 
Note that the line of formation 38 is parallel to the side wall 34a. An 
end wall 33a is connected at the side wall 34a. The end wall 33a is also 
seen to intersect the line of formation 38. The side wall 34a and the end 
wall 33a also include an integrally formed arcuate corner 41 that unites 
them. 
Due to the arcuate shape of the side wall 34a, a rectangular opening 42 
shown in dotted line in FIG. 8, is provided that is parallel to the line 
of formation 38 as well as an arcuate opening 43 shown in dotted line in 
FIG. 6. The arcuate opening 43 is seen to be normal to the line of 
formation 38 and is positioned opposite to the end wall 33a. 
Positionwise, the rectangular opening 42 is offset to one side of the line 
of formation 38 at the termination of the side wall 34a. Result: the 
combined area of the side wall 34a and the end wall 33a is slightly 
greater than that of a conventional half annulus of similar shape and 
dimensions. 
In operations as explained in more detail below, the rectangular opening 42 
and/or arcuate opening 43 of the quasi-half annulus 31 are also flexibly 
workable to permit entry within or without the other intermediate 
quasi-half annulus 32 so as to form the full annulus 30 as shown in FIGS. 
1-4. Note in this regard, that unification of the quasi-half annuli 31, 32 
is along the U-shaped overlap region 35 of common transverse and 
circumferential length W, previously mentioned. 
As shown, the U-shaped overlap region 35 is described as being defined by 
transverse and circumferential width W because such width W is transverse 
to the axis of symmetry 17 relative to the end wall 33 as shown in FIG. 1 
but is also circumferential extending relative to the side wall 34. 
Returning to FIG. 4, assume that Wi is the transverse or circumferential 
distance measured from the line of formation 38 to a termination point 
associated with the following: at end surface 44 of the end wall 33a or at 
end surface 45 of the side wall 34a of the quasi-half annulus 31. Note in 
FIG. 9 that the raised punch mark or dot 36 is coincident with the line of 
formation 38. 
As shown in FIG. 3, the raised punch marks or dots 36 associated with the 
half-quasi annuli 31, 32 become axially aligned relative to each other 
after assembly. That is to say, the dot 36 of the quasi-half annulus 31 is 
axially stacked adjacent to the dot 36 of the quasi-half annulus 32. Thus, 
width W of the overlap region 35 is equal to 
EQU 2 W1 
where W1 is the transverse distance from the raised dot 36 to the end 
surface 44 of the end wall 33a associated with quasi-half annuli 31, 32 or 
to end surface 45 of the side wall 34a associated with the quasi-half 
annuli 31, 32, see FIG. 4. 
Additionally, a maximum chord length L of the end wall 33a is seen to FIGS. 
6 and 8 is also defined at the end wall 33a. It is measured from the 
outside surface 49 of side wall 34a through the line of formation 38 and 
terminates at end surface 44 of the end wall 33a and is equal 
EQU R+Wi 
and R is the outside radius of the side wall 34a and Wi is the transverse 
distance from raised dot 36 to the end surface 44 of the end wall 33a. 
FIGS. 11-14 show a fixture 52 of producing--in sequence--the pair of 
quasi-half annuli 31, 32 of FIG. 4. 
As shown, the fixture 52 comprises a die plate 50 and punch plate 51. A 
coil of feed blank 53 of metal is fed to the fixture 52 for providing a 
succession of quasi-half annuli 31, 32 illustrated in FIG. 4 on a 
systematic basis. In this regard, note that the feed blank 53 has already 
been trimmed in the transverse direction indicated by arrow T to provide a 
chord length that is slightly greater than the chord length L for the 
finished quasi-half annulus 31 or 32. The feed blank 53 is seen to be a 
rather thin gauge metal such as aluminum and to include a thickness t 
which is in a range of 0.01 to 0.024 inches. 
As shown in FIG. 13, the die plate 50 includes a planar support 54 having a 
broad surface 55 on which an annular groove 56 is formed. The annular 
groove 56 includes a rolling edge 57 and a cutting edge 58. A center of 
formation 59 is located relative to the groove 56 and defines a radius Ro 
(where Ro is equal to R+t) extending from the center of formation 59 to 
rolling edge 57. A pick punch 61 is seen to be located at the center of 
formation 59, see FIG. 12. 
As shown in FIG. 11 and 12, a guide assembly 62 attached to the planar 
support 54 and includes two sets of cylindrical guides 63 and 64 that 
protrude therefrom as shown. The set of guides 63, 64 not only position 
the feed bland 53 relative to the die plate 50 and punch plate 51 but to 
also guide the movement of punch plate 51 relative to the die plate 50. 
The punch plate 51 includes a planar support 65 supported above the die 
plate 50 having undersurface 68a that includes an annular ridge 67 
designed to mate with the arcuate groove 56. The shape and dimensions of 
the ridge 67 allow for cutting at cutting corner 68 and folding at folding 
corner 69 as explained in detail below. External broad surface 66b of the 
planar support 65 is seen to include a shaft 70 attached to a driver 
mechanism 71 of say a stamping machine, not shown, that provides 
rectilinear movement of the punch plate 51 in the direction of arrow 72. 
During such movement (usually parallel to the earth's gravitational 
field), guide holes 72 in the punch plate 51 permit penetration by the set 
of guides 63 to direct the punch plate 51 in the correct path into contact 
with the feed bland 53 to form the quasi-half annulus 31 or 32 in the 
following manner. 
First, the feed blank 53 is positioned within the fixture 52 between the 
die plate 50 and punch plate 51 in an open position. Then the punch plate 
51 is activated via the drive mechanism 71 to close the fixture 52 to 
initiate the activation stroke thereof. Result: the angular ridge 67 of 
the punch plate 51 is brought into cutting contact the feed blank 53 along 
an imaginary arcuate cut line indicated at 75 in FIG. 11 on the feed blank 
53 normalized relative to center of formation 59 and thereafter into 
folding contact via an arcuate fold line indicated at 77, both cut line 75 
and fold line 77 being positioned above the arcuate groove 56 of the die 
plate 50, see FIG. 12. Because of the shape of the annular ridge 67 and 
annular groove 56, cutting of the feed blank 53 first occurs at cutting 
edge 58 and cutting corner 68 of the fixture 52 before a resulting trimmed 
blank edge of the feed blank 53 is folded ("crimped") about the rolling 
edge 57 and folding corner 69 of the fixture 52. The direction of such 
folding of such edge region is shown by phantom line 74. Thereafter, the 
drive mechanism 71 causes the fixture 52 to return to its open position 
during a return stroke so that the resulting formed quasi-half annulus 31 
or 32 can be removed. Then the method is repeated to provide the mating 
quasi-half annulus 32 or 31 in similar manner. After deburring edges, the 
quasi-half annuli 31, 32 are provided with openings 80, see FIG. 4, 
through which fasteners 81, see FIG. 1 extend to not only unite the 
quasi-half annuli 31, 32 but attach the resulting full annulus 30 relative 
to the jacket 27 of the insulated pipe 12. 
To recap, the method of the present invention include the steps of: 
(a) placing feed blank 53 of metal in stamping fixture 52 comprising a 
planar die plate 50 and a planar punch plate 51, 
(b) activating the punch plate 51 to initially cut the blank 53 along 
arcuate cut line 75 normalized to center of formation 59 centered at the 
fixture 52 and then folding the cut blank along second arcuate fold line 
77 offset interior of the cut line 75 to form integrally formed arcuate 
corner 41 (see FIG. 10) wherein the intermediate quasi-half metallic 
annulus 31 or 32 is completely formed. 
Thereafter the formed quasi-half metallic annuli 31, 32 are mounted about 
or at the end of an insulated pipe by flexibly working the openings 42, 43 
of say quasi-half annulus 31 to permit its entry within or without the 
other intermediate quasi-half annulus 32 so as to form the full annulus 30 
as shown in FIG. 1 in weather-proofing protection of insulated pipe 12. 
Note in this regard, that unification of the quasi-half annuli 31, 32 is 
along the U-shaped overlap region 35 of common transverse and 
circumferential length W, previously mentioned.