PRODUCTION OF PIPE BEND SHEATHS
United States Patent 3825412
A corrugated plastic or metal foil sheet, for use as an intermediate product in the production of pipe bend sheaths, is longitudinally and transversely arcuately corrugated so that it can be cut longitudinally and transversely into pieces each of which constitutes a sheath in opened shape which can be turned into closed pipe bend shape.
US Patent References:
/1566768.html
Otis - December 1925 - 1566768
Pipe elbow
Hickey - June 1935 - 2003538
Sheet metal stock for paneling and other purposes
Wikson - March 1939 - 2152297
Construction elements
Rubissow - October 1961 - 3003599
/1566768.html
Otis - December 1925 - 1566768
Pipe elbow
Hickey - June 1935 - 2003538
Sheet metal stock for paneling and other purposes
Wikson - March 1939 - 2152297
Construction elements
Rubissow - October 1961 - 3003599
Application Number:
05/224736
Publication Date:
07/23/1974
Filing Date:
02/09/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
428/577, 428/571, 428/174, 29/415, 428/181, 428/182, 29/890.053
International Classes:
F16L59/11; F16L59/10; B32B15/00
Field of Search:
29/412,415,417,157A,18SS,193.5,190 113/116UT,116BB 285/183,424 161/125,133,132
Primary Examiner:
Herbst, Richard J.
Attorney, Agent or Firm:
O'brien, Anthony A.
Claims:
I claim
1. A corrugated sheet useful as an intermediary product in the production of sheaths for objects having a generally pipe bend shaped external surface defined by curved inner and outer bend sections comprising:
2. A corrugated sheet according to claim 1 wherein at least some of said pluralities of elongated segments have cusps therein increasing the dimension of the material on either side thereof thereby enabling the corrugated sheet to be divided into pieces forming sheaths having ends which will overlap when closed in pipe bend shape.
3. A corrugated sheet according to claim 2 wherein the cusps extend continuously along the elongated segments in a direction parallel to said longitudinal axes.
4. A corrugated sheet according to claim 2 wherein the cusps are disposed parallel to said longitudinal axes and are in alignment along a line transverse to said longitudinal axes.
1. A corrugated sheet useful as an intermediary product in the production of sheaths for objects having a generally pipe bend shaped external surface defined by curved inner and outer bend sections comprising:
2. A corrugated sheet according to claim 1 wherein at least some of said pluralities of elongated segments have cusps therein increasing the dimension of the material on either side thereof thereby enabling the corrugated sheet to be divided into pieces forming sheaths having ends which will overlap when closed in pipe bend shape.
3. A corrugated sheet according to claim 2 wherein the cusps extend continuously along the elongated segments in a direction parallel to said longitudinal axes.
4. A corrugated sheet according to claim 2 wherein the cusps are disposed parallel to said longitudinal axes and are in alignment along a line transverse to said longitudinal axes.
Description:
This invention relates to the production of sheaths for objects having a generally pipe bend shaped outer surface defined by curved inner and outer bend sections, and more particularly to the production of pipe bend sheaths which are used for covering thermal insulation, such as foam material, laid on pipes or tubes to be insulated, especially in central heating systems.
A particular form of such sheaths, and their production, is the subject of my co-pending application whereas the present application Ser. No. 224,889 is concerned with the production of a variety of sheaths, not limited to that particular form, and is based on an intermediate product, comprising a specially shaped sheet of flexible resiliently deformable material, such as a plastic or metal foil or film, from which sheaths can economically be divided.
According to the invention, a corrugated sheet, for use as an intermediate product in the production of pipe bend sheaths, consists of flexible resiliently deformable material of longitudinally and transversely arcuately corrugated form, the corrugations extending in parallel rows which mutually intersect in the longitudinal and transverse directions, each row of corrugations in the longitudinal direction having a regularly sinuous profile of substantially semicircular alternating hills and valleys, as seen from either face of the sheet, and each row of corrugations in the transverse direction having a form which, as seen from one face of the sheet, appears as substantially quadrantal hills alternating with V-shaped valleys and, as seen from the other face of the sheet, appears as substantially quadrantal valleys alternating with inverted or saddleback pass shaped hills.
The method in accordance with the invention of producing sheaths comprises cutting a corrugated sheet, as defined above, longitudinally and transversely into pieces each of which comprises in longitudinal extent substantially the equivalent of a semicircular hill plus a semicircular valley so that each piece can be resiliently deformed into an annulus of pipe bend shape.
Alternative ways in which the sheet may be cut and other features of the invention are included in the following description with reference, by way of example, to the accompanying drawings, in which:
FIGS. 1a to c show in plan, longitudinal section and transverse section respectively a corrugated sheet in accordance with the invention,
FIGS. 2a and b show in plan and side elevation respectively a longitudinal row of corrugations cut from the sheet of FIGS. 1a to c, and
FIGS. 3, 4, 5 and 6 are longitudinal sections of part of a row of corrugations, corresponding to part of FIG. 1b or FIG. 2b, illustrating modifications.
FIG. 1a shows in plan an embossed corrugated sheet formed, by a pressing or other moulding process, from a plane sheet of foil. This forming is carried out in such a way that there are produced transverse undulating corrugations 30, 32 and longitudinal undulating corrugations 31, 33 which succeed one another periodically and symmetrically in parallel rows which mutually intersect in the transverse and longitudinal directions. The result is that, as seen from either face of the sheet, longitudinal rows of convex corrugation hills, 34 or 37, and concave corrugation valleys, 35 or 36, are produced, are all substantially semicircular as seen in longitudinal section and adjoin one another in continuous transition. The semicircles correspond in diameter to the pipe diameter of the closed annulus form of the pipe bend sheaths to be produced. This diameter is substantially that of the pipe, including its insulation, to be covered.
In transverse section, the rows of corrugation hills 34, 37 and corrugation valleys 35, 36 have the profile of quarter-circles interconnected by straight parts 42, 43 which correspond to the ends of the pipe bend shape, to connect with adjacent straight lengths of pipe sheathing. The corrugation valleys 35, 36 correspond, when eventually inverted, to the throats or inner sides of the bends of eventual sheaths and the corrugation hills 34, 37 eventually form the outer sides of the bends of eventual sheaths.
in FIG. 1b, which is a section along the line I--I in FIG. 1a, there can be seen one side of one longitudinal row of corrugations. In FIG. 1c, which is a section on the line II--II in FIG. 1a, there can be seen one side of a transverse row of corrugations.
Longitudinally, as shown by FIG. 1b, alternately convex and concave semicircles adjoin one another to form regular rows of hills and valleys as seen from either side of the sheet. In FIG. 1c, successively large and small quarter-circles are interconnected by straight parts 42, 43 so that each transverse row of corrugations appears, from one face of the sheet, as alternating quadrantal hills and V-shaped valleys and, from the other face, as alternating quadrantal valleys and inverted V or saddleback pass shaped hills.
If the corrugated sheet is now cut into longitudinal strips, along the chain lines in FIGS. 1a and c, then rows of corrugations are produced, as represented in plan view in FIG. 2a, corresponding to the plan view in FIG. 1a, and in side elevation in FIG. 2b, similarly to the section of FIG. 1b. In the case of the section of FIG. 1b, a section surface is obtained which lies in the plane of the drawing, while with the row of corrugations of FIG. 2b the front edge 44, which intersects perpendicularly the straight parts 42, lies in a plane oblique to the plane of the drawing. Each longitudinal strip of corrugations, having been cut, through 42 and 43, in mutually perpendicular planes intersecting along the axis of the strip, consists of a quadrantal sector of a hollow body of sinuous profile.
The individual sheaths are now separated from these rows of corrugations by cutting the strips across.
By suitable choice of the position of the dividing cuts various forms of sheaths can be obtained, each in an opened shape which can be turned, by resilient deformation of the material, into a closed shape of pipe bend form.
If the dividing cuts are made straight across at or near the peaks of longitudinal hills, such as at 70 and 71, then each intervening piece 72 constitutes a pipe bend sheath in an opened shape having the form of a quadrantal sector of a hollow body of open-ended hour-glass form as can be seen in FIG. 2a.
To close the piece of material 72 into pipe bend shape, the convex ends, defined by the cuts 70 and 71, are drawn towards one another so as to invert the corrugation valley, or waist portion of the hour-glass shape, the ends closing together to form the outer side of the pipe bend and the corrugation valley or waist portion the throat thereof. Due to the embossing of the original sheet, the sheath material is stressed so that it is resiliently stable in both the opened, hour-glass, shape and in the closed, pipe-bend, shape into which it will snap automatically when the valley or waist portion is inverted. This form of sheath is described in more detail in my above-mentioned co-pending application and need not be more fully described in this application which is concerned with the production of sheaths including, but not limited to, that form of sheath.
If dividing cuts are made through the valley portions, such as at 73 and 74, then each intervening piece 75 has the shape somewhat of a helmet or Dutch bonnet. If the ends 80 and 81 of a piece 75 are then drawn together they will invert and meet or overlap to form the throat of a pipe bend sheath whilst the hill portion between them forms the outer side of the bend.
Thus, a longitudinal strip as shown by FIGS. 2a and b can be cut across its hills or valleys into pieces each of which comprises in longitudinal extent substantially the equivalent of a semicircular hill plus a semicircular valley so that each piece can be resiliently deformed into an annulus of pipe-bend shape.
Preferably the dividing cuts are so positioned that the ends of each piece produced will overlap in the closed shape, either at the outside of the bend for a piece such as 72 or at the throat of the bend for a piece such as 75. For example, the convex end portion of the piece 72 cut off at 71 is somewhat longer than the other end. Only a small difference is required and the positions of the cuts can change progressively along a row so that only occasionally a small longitudinal piece, of less than sheath length, need be discarded.
The corrugated strips may be cut obliquely, such as at 76 and 77, to produce sheath pieces, such as 78, of which the ends inversely vary in length transversely. The oblique ends can, when the sheath is turned to closed shape, meet with an oblique butt joint or, by a slight helical conformation of the closed sheath, the oblique ends can be caused to overlap.
For economy, each corrugated strip will be divided into similar pieces by similarly located straight or oblique transverse cuts, with any slight variation to obtain overlap, so as to avoid waste by pieces of incomplete sheath size being left between adjacent cuts. It may however be possible to change from a series of cuts of one kind, such as 70, 71, to another kind, such as 73, 74, by progressive shift in longitudinal position of the cuts.
In order to provide for overlap of sheath ends without changing the position of transverse dividing cuts, the embossed shape of the production sheet can be modified so as locally to increase the longitudinal dimensions of the eventual ends of sheaths and thus provide for overlap. The necessary local dimensional increase can be provided by cusps in the curvature of the longitudinal hills or valleys at transverse dividing lines defined by transverse indentations or ridges respectively.
In one example, illustrated by FIG. 3, the crests or peaks of longitudinal hills, such as 34 in FIG. 1b, are bulged slightly on either side of a transverse cusp 90 which crosses adjacent valleys, such as 35, which appear as hills from the other side of the sheet. In the moulding, the cusp 90 may change from one face of the sheet to the other so as to appear as an indentation or as a ridge at the eventual dividing cut for the respective strip of corrugations.
The moulding may however be such that transverse ridges are formed across longitudinal valleys as shown by the cusp 91 in FIG. 4. If dividing cuts are made at ridges, such as at 91, the intervening pieces are of helmet or Dutch bonnet shape and, when closed, overlap at the throats of their pipe sheath bends.
If it is desired to produce, from one and the same embossed production sheet, sheaths which are all of the same shape, i.e., all of the hour-glass shape such as 72 or all of the helmet shape such as 75, then only short transverse cusps need be formed transversely within each longitudinal row, i.e., eventual strip, of corrugations.
The cusps required for helmet-type pieces are shown at 92 and 93 in FIG. 5, and by corresponding thick chain lines in FIG. 1a, extending transversely within valleys 35' and 36' of adjacent longitudinal strip rows of corrugations from which will be cut sheaths which overlap their ends at the throats of bends.
As shown in FIG. 6, for hour-glass type sheaths, somewhat longer transverse cusps 94 and 95 are made across the crests or peaks of hills 34' and 37' of adjacent longitudinal strip rows of corrugations from which will be cut sheaths which overlap their ends at the outer side of bends.
Sheets which are corrugated for division into pipe bend sheaths as described above may be moulded from any suitable flexible resiliently deformable material such as plastics foil or film or metal sheet or foil.
It will be apparent that sheaths may be produced in a factory by successive sheet-forming and dividing operations or corrugated sheets may be produced as intermediate products manufactured as articles for sale to factors or other users who can divide the sheets into sheaths.
A particular form of such sheaths, and their production, is the subject of my co-pending application whereas the present application Ser. No. 224,889 is concerned with the production of a variety of sheaths, not limited to that particular form, and is based on an intermediate product, comprising a specially shaped sheet of flexible resiliently deformable material, such as a plastic or metal foil or film, from which sheaths can economically be divided.
According to the invention, a corrugated sheet, for use as an intermediate product in the production of pipe bend sheaths, consists of flexible resiliently deformable material of longitudinally and transversely arcuately corrugated form, the corrugations extending in parallel rows which mutually intersect in the longitudinal and transverse directions, each row of corrugations in the longitudinal direction having a regularly sinuous profile of substantially semicircular alternating hills and valleys, as seen from either face of the sheet, and each row of corrugations in the transverse direction having a form which, as seen from one face of the sheet, appears as substantially quadrantal hills alternating with V-shaped valleys and, as seen from the other face of the sheet, appears as substantially quadrantal valleys alternating with inverted or saddleback pass shaped hills.
The method in accordance with the invention of producing sheaths comprises cutting a corrugated sheet, as defined above, longitudinally and transversely into pieces each of which comprises in longitudinal extent substantially the equivalent of a semicircular hill plus a semicircular valley so that each piece can be resiliently deformed into an annulus of pipe bend shape.
Alternative ways in which the sheet may be cut and other features of the invention are included in the following description with reference, by way of example, to the accompanying drawings, in which:
FIGS. 1a to c show in plan, longitudinal section and transverse section respectively a corrugated sheet in accordance with the invention,
FIGS. 2a and b show in plan and side elevation respectively a longitudinal row of corrugations cut from the sheet of FIGS. 1a to c, and
FIGS. 3, 4, 5 and 6 are longitudinal sections of part of a row of corrugations, corresponding to part of FIG. 1b or FIG. 2b, illustrating modifications.
FIG. 1a shows in plan an embossed corrugated sheet formed, by a pressing or other moulding process, from a plane sheet of foil. This forming is carried out in such a way that there are produced transverse undulating corrugations 30, 32 and longitudinal undulating corrugations 31, 33 which succeed one another periodically and symmetrically in parallel rows which mutually intersect in the transverse and longitudinal directions. The result is that, as seen from either face of the sheet, longitudinal rows of convex corrugation hills, 34 or 37, and concave corrugation valleys, 35 or 36, are produced, are all substantially semicircular as seen in longitudinal section and adjoin one another in continuous transition. The semicircles correspond in diameter to the pipe diameter of the closed annulus form of the pipe bend sheaths to be produced. This diameter is substantially that of the pipe, including its insulation, to be covered.
In transverse section, the rows of corrugation hills 34, 37 and corrugation valleys 35, 36 have the profile of quarter-circles interconnected by straight parts 42, 43 which correspond to the ends of the pipe bend shape, to connect with adjacent straight lengths of pipe sheathing. The corrugation valleys 35, 36 correspond, when eventually inverted, to the throats or inner sides of the bends of eventual sheaths and the corrugation hills 34, 37 eventually form the outer sides of the bends of eventual sheaths.
in FIG. 1b, which is a section along the line I--I in FIG. 1a, there can be seen one side of one longitudinal row of corrugations. In FIG. 1c, which is a section on the line II--II in FIG. 1a, there can be seen one side of a transverse row of corrugations.
Longitudinally, as shown by FIG. 1b, alternately convex and concave semicircles adjoin one another to form regular rows of hills and valleys as seen from either side of the sheet. In FIG. 1c, successively large and small quarter-circles are interconnected by straight parts 42, 43 so that each transverse row of corrugations appears, from one face of the sheet, as alternating quadrantal hills and V-shaped valleys and, from the other face, as alternating quadrantal valleys and inverted V or saddleback pass shaped hills.
If the corrugated sheet is now cut into longitudinal strips, along the chain lines in FIGS. 1a and c, then rows of corrugations are produced, as represented in plan view in FIG. 2a, corresponding to the plan view in FIG. 1a, and in side elevation in FIG. 2b, similarly to the section of FIG. 1b. In the case of the section of FIG. 1b, a section surface is obtained which lies in the plane of the drawing, while with the row of corrugations of FIG. 2b the front edge 44, which intersects perpendicularly the straight parts 42, lies in a plane oblique to the plane of the drawing. Each longitudinal strip of corrugations, having been cut, through 42 and 43, in mutually perpendicular planes intersecting along the axis of the strip, consists of a quadrantal sector of a hollow body of sinuous profile.
The individual sheaths are now separated from these rows of corrugations by cutting the strips across.
By suitable choice of the position of the dividing cuts various forms of sheaths can be obtained, each in an opened shape which can be turned, by resilient deformation of the material, into a closed shape of pipe bend form.
If the dividing cuts are made straight across at or near the peaks of longitudinal hills, such as at 70 and 71, then each intervening piece 72 constitutes a pipe bend sheath in an opened shape having the form of a quadrantal sector of a hollow body of open-ended hour-glass form as can be seen in FIG. 2a.
To close the piece of material 72 into pipe bend shape, the convex ends, defined by the cuts 70 and 71, are drawn towards one another so as to invert the corrugation valley, or waist portion of the hour-glass shape, the ends closing together to form the outer side of the pipe bend and the corrugation valley or waist portion the throat thereof. Due to the embossing of the original sheet, the sheath material is stressed so that it is resiliently stable in both the opened, hour-glass, shape and in the closed, pipe-bend, shape into which it will snap automatically when the valley or waist portion is inverted. This form of sheath is described in more detail in my above-mentioned co-pending application and need not be more fully described in this application which is concerned with the production of sheaths including, but not limited to, that form of sheath.
If dividing cuts are made through the valley portions, such as at 73 and 74, then each intervening piece 75 has the shape somewhat of a helmet or Dutch bonnet. If the ends 80 and 81 of a piece 75 are then drawn together they will invert and meet or overlap to form the throat of a pipe bend sheath whilst the hill portion between them forms the outer side of the bend.
Thus, a longitudinal strip as shown by FIGS. 2a and b can be cut across its hills or valleys into pieces each of which comprises in longitudinal extent substantially the equivalent of a semicircular hill plus a semicircular valley so that each piece can be resiliently deformed into an annulus of pipe-bend shape.
Preferably the dividing cuts are so positioned that the ends of each piece produced will overlap in the closed shape, either at the outside of the bend for a piece such as 72 or at the throat of the bend for a piece such as 75. For example, the convex end portion of the piece 72 cut off at 71 is somewhat longer than the other end. Only a small difference is required and the positions of the cuts can change progressively along a row so that only occasionally a small longitudinal piece, of less than sheath length, need be discarded.
The corrugated strips may be cut obliquely, such as at 76 and 77, to produce sheath pieces, such as 78, of which the ends inversely vary in length transversely. The oblique ends can, when the sheath is turned to closed shape, meet with an oblique butt joint or, by a slight helical conformation of the closed sheath, the oblique ends can be caused to overlap.
For economy, each corrugated strip will be divided into similar pieces by similarly located straight or oblique transverse cuts, with any slight variation to obtain overlap, so as to avoid waste by pieces of incomplete sheath size being left between adjacent cuts. It may however be possible to change from a series of cuts of one kind, such as 70, 71, to another kind, such as 73, 74, by progressive shift in longitudinal position of the cuts.
In order to provide for overlap of sheath ends without changing the position of transverse dividing cuts, the embossed shape of the production sheet can be modified so as locally to increase the longitudinal dimensions of the eventual ends of sheaths and thus provide for overlap. The necessary local dimensional increase can be provided by cusps in the curvature of the longitudinal hills or valleys at transverse dividing lines defined by transverse indentations or ridges respectively.
In one example, illustrated by FIG. 3, the crests or peaks of longitudinal hills, such as 34 in FIG. 1b, are bulged slightly on either side of a transverse cusp 90 which crosses adjacent valleys, such as 35, which appear as hills from the other side of the sheet. In the moulding, the cusp 90 may change from one face of the sheet to the other so as to appear as an indentation or as a ridge at the eventual dividing cut for the respective strip of corrugations.
The moulding may however be such that transverse ridges are formed across longitudinal valleys as shown by the cusp 91 in FIG. 4. If dividing cuts are made at ridges, such as at 91, the intervening pieces are of helmet or Dutch bonnet shape and, when closed, overlap at the throats of their pipe sheath bends.
If it is desired to produce, from one and the same embossed production sheet, sheaths which are all of the same shape, i.e., all of the hour-glass shape such as 72 or all of the helmet shape such as 75, then only short transverse cusps need be formed transversely within each longitudinal row, i.e., eventual strip, of corrugations.
The cusps required for helmet-type pieces are shown at 92 and 93 in FIG. 5, and by corresponding thick chain lines in FIG. 1a, extending transversely within valleys 35' and 36' of adjacent longitudinal strip rows of corrugations from which will be cut sheaths which overlap their ends at the throats of bends.
As shown in FIG. 6, for hour-glass type sheaths, somewhat longer transverse cusps 94 and 95 are made across the crests or peaks of hills 34' and 37' of adjacent longitudinal strip rows of corrugations from which will be cut sheaths which overlap their ends at the outer side of bends.
Sheets which are corrugated for division into pipe bend sheaths as described above may be moulded from any suitable flexible resiliently deformable material such as plastics foil or film or metal sheet or foil.
It will be apparent that sheaths may be produced in a factory by successive sheet-forming and dividing operations or corrugated sheets may be produced as intermediate products manufactured as articles for sale to factors or other users who can divide the sheets into sheaths.