US 2157983 A
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Description (OCR text may contain errors)
I May 9, 1939. B. s GLOUGIE S EAL Filed Feb. 5, 1956 BY BERT STANLEY GLOUGIE 1N VEN TOR A TTORNEYS Patented May 9, i939 SEAL Bert Stanley Glougie, Pontiac, Mich assignor to Baldwin Rubber Company, Pontiac, Mich., a corporation of Michigan Application February 3, 1936, Serial No. 62,219
. This invention relates generally to seals and refers mlore particularly to an improved seal for molding apparatus of the type employing fluid under pressure to urge the stock into intimate 5 contacting relation with a contoured f0rm..
Although it will be understood as this description proceeds that my improved seal is capable of numerous and diversified uses, nevertheless, it finds particular utility when employed to provide a seal between relatively movable sections of a fluid pressure chamber or mold. In accordance with the illustrative embodiment of the invention a strip of flexible material such as rubber is fixed to one of the relatively movable parts of the mold for engagement with the other cooperating part in the relative position the same assume when forming the fluid pressure chamber, and it is one of the principal objects of the present invention to provide a seal of the character wherein the pressure of the fluid confined in the chamber acts upon the seal to intimately engage the same with both of the aforesaid parts of the mold. This arrangement is of particular utility in cases where the parts of the mold are mounted for relative sliding movement adjacent the sealing strip, since it renders it possible to so adjust the parts that during relative sliding movement of the same very little or no pressure is exerted on one of the parts by the seal mounted on the other of the parts. In other words, the seal functions only in the relative position of the parts required to form the fluid pressure chamher, and, accordingly, during relative movement of the parts to any of the other positions thereof the seal may be relieved from frictional. en-
gagement. This appreciably reduces the wear of the seal and also provides for minimizing the power required to effect the desired relative movement of the parts of the mold.
The foregoing, as well as other objects, will be made more apparent as this description proceeds especially when considered in connection with the accompanying drawing, wherein:
Figure 1 is'a side elevational view of a mold equipped with a ,se al constructed in accordance with this inventioii;
Figure 2 is a sectional view taken substantially on the plane indicated by the line 22 of Figure 1;
Figure 3 is a cross sectional the line 3-3 of Figure 2. b
Although the seal forming the subject matter of this invention may be advantageously employed in all cases where it is desired to conflne' fluid under pressure in a chamber, nevertheless,
view taken. on
for the purpose of illustration, I have shown my improved seal in connection with apparatus for forming yieldable stock to a predeterminedcontour by placing the stock on a suitable contoured form and subjecting the same to the action of fluid pressure preferably heated to the temperature required to vulcanize or cure the stock to the contour of the form.
Referring now more in detail to the drawing, it will be noted that I have illustrated in the several views a molding device l0, comprising a platen H, and a header 12. In the present instance the platen l I is-mounted for sliding movement relative to the header I2 and cooperates with the latter in one position to form a fluid pressure chamber l3 communicating with a source of fluid supply (not shown) through a suitable passage in the header.
In the illustrative embodiment of the invention a contoured form I! is secured upon'the inner surface of the bottom wall iii of the platen in any suitable manner, and this forniis adapted to support a sheet of uncured stock designated herein by the reference character A. The stock A is positioned upon the form I4 when the platen II is moved relative to the header I! to a position wherein the interior of the platen is suifiv ciently exposed to permit the stock to beinserted therein through the top of the same. After the stock. has been properly positioned upon the contoured form the platen is mpvedto its closed position with respect to the header l2, wherein the same cooperates with the latter to form the chamber l3, and fluid under sufficient pressure is introduced into the chamber I3 through the header to force the stock into intimate engagement with the contoured surface of the form l4. As stated above, this fluid is prefably of sufficient temperature to actually cure or vulcanize the.stock to the contour of the form.
It will be apparent from the foregoing that the success of the forming operation briefly outlined above depends to a great extent upon the ability of the chamber l3 to confine the fluid pressure during the molding operation, and this is effectively accomplished in the present instance by my improved type of seal designated in the several views of the drawing by the reference, character IS. AS shown particularly in Figure 3- of the drawing, the seal I6 is in the form of a continuous strip of material I! secured to the platen ll adjacent the header I! for engagement with theunder side of the header. The strip I1 is preferably formed of rubber, or of a material containing rubber. and is secured within a continuous recess l8 formed in the upper edges of the side walls I! of the platen.
.throughoutthe length thereof with the interior of the chamber 13 by means of passages 2 l. The arrangement is-such that fluid under pressure introduced into the chamber l3 through the header If not only acts upon the stock A to mold the same to the contour of the form I4, but also flows through the passages 2| into the chamber beneath the strip l1 and acts upon the concaved bottom surface of the strip I! to flex the strip in an upward direction the extent required to intimately engage a portion of the arcuate top surface of the strip with the header I2. It may be pointed out in this connection that the area of the concaved bottom surface of the strip H, exposed to the chamber I3, is substantially greater than the area of the sealing surface inorder to effect the pressure differential required to provide an efficient seal.
When the fluid under pressure in the chamber I3 is exhausted after the molding operation the pressure on the concave bottom surface of the sealing strip i1 is relieved, permitting the strip to return to its original position, and the construction is preferably such that when the strip returnsto its normal position the top or sealing surface of the strip is substantially free from frictional contact with the header. As previously stated, this is desirable not only because it appreciably increases the life of the seal, notwithstanding the periodic sliding movement of the platen, but also because it reduces the power required to actually effect sliding movement of the platen.
While in describing the present invention particular stress has been'placed upon the association of my improved seal with a sliding platen, nevertheless, it is to be understood that the seal is by no means-limited to this specific application, and reservation is'made to make such changes in the construction as may come within the purview of the accompanying claims.
What I claim as my invention is:
1. A seal for fluid chambers having relatively movable sections cooperating in one relative position thereof to form a fluid pressure chamber, said seal carried by one of the sections and comprising a deformable strip having a sealing surface convex in cross section for engagement withthe cooperating section in the aforesaid relative position of the sections and having an opposed surface exposed to the action of the fluid under pressure in the chamber to force said convex surface into engagement with said cooperating section, the area of the surface exposed to the fluid pressure being larger than the area of contact between the convex sealing surface and the cooperating section to create a unit pressure be-- tween said convex surface and said cooperating section which is greater than the unit pressure of the fluid in the chamber.
2. A seal for fluid chambers having relatively movable sections cooperating in one relative position thereof to form a fluid pressure chamber, said seal carried by oneof the sections and comprising a deformable strip having a sealing surface convex ln cross section for engagement with the cooperating section in the aforesaid relative position of the sections and having'an opposed concave surface exposed to the action of the fluid under pressure in the chamber to force said convexsurface into engagement with said cooperating section, the area of said concave surface being greater than the area of contact between the convex sealing surface and the cooperating section tocreate'a unit pressure between said convex surface and said cooperating section which is greater than the unit pressure of the fluid in the chamber.
3. A seal for fluid chambers having relatively movable sections cooperating in one relative position thereof to form a fluid pressure chamber, one of said sections having a groove therein adapted to receive the seal, said seal having a sealing surface engageable with another of the sections in the aforesaid relative position of the sections and having an opposed surface exposed to the action of fluid under pressure in the chamber, the-area of that portion of the sealing surface of the seal which engages the second-mentioned section being smaller than either the area of the groove at the surface of the first-mentioned section or. the area of the seal exposed to the action of fluid pressure in the chamber to provide a unit pressure at the sealing surface greater than the unit pressure of the fluid in the chamber.
4. A seal for fluid chambers having a pair of relatively movable sections one of which is provided with a-groove having parallel side walls, said seal being positioned in said groove'and having a sealing surface engageable with the other of said sections and having an exposed surface exposed to the action of fluid under pressure in the chamber, the area of the surface exposed to fluid pressure being greater than the area of contact between the sealing surface and the second-mentioned section to create a unit pressure at said area of contact greater than the unit pressure of the fluid in the chamber.
BERT STANLEY GLOUGIE.