CA1193824A - Sealing system for eavestroughing - Google Patents
Sealing system for eavestroughingInfo
- Publication number
- CA1193824A CA1193824A CA000438598A CA438598A CA1193824A CA 1193824 A CA1193824 A CA 1193824A CA 000438598 A CA000438598 A CA 000438598A CA 438598 A CA438598 A CA 438598A CA 1193824 A CA1193824 A CA 1193824A
- Authority
- CA
- Canada
- Prior art keywords
- gasket
- connector
- vinyl chloride
- poly
- male mold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000007789 sealing Methods 0.000 title claims abstract description 41
- 239000000463 material Substances 0.000 claims abstract description 63
- 238000000034 method Methods 0.000 claims abstract description 31
- 229920003023 plastic Polymers 0.000 claims abstract description 28
- 239000004033 plastic Substances 0.000 claims abstract description 28
- 238000009826 distribution Methods 0.000 claims abstract description 18
- 238000002347 injection Methods 0.000 claims abstract description 12
- 239000007924 injection Substances 0.000 claims abstract description 12
- 238000001816 cooling Methods 0.000 claims abstract description 11
- 238000010438 heat treatment Methods 0.000 claims abstract description 5
- 229920002457 flexible plastic Polymers 0.000 claims abstract 3
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 31
- 239000004800 polyvinyl chloride Substances 0.000 claims description 31
- 230000007704 transition Effects 0.000 claims description 7
- 239000012809 cooling fluid Substances 0.000 claims description 4
- 238000005452 bending Methods 0.000 claims description 3
- 238000004891 communication Methods 0.000 claims 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims 2
- 239000012768 molten material Substances 0.000 claims 1
- 238000000465 moulding Methods 0.000 abstract description 4
- 238000001746 injection moulding Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 2
- 238000004026 adhesive bonding Methods 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
- E04D13/00—Special arrangements or devices in connection with roof coverings; Protection against birds; Roof drainage ; Sky-lights
- E04D13/04—Roof drainage; Drainage fittings in flat roofs, balconies or the like
- E04D13/064—Gutters
- E04D13/0641—Gutter ends
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
- E04D13/00—Special arrangements or devices in connection with roof coverings; Protection against birds; Roof drainage ; Sky-lights
- E04D13/04—Roof drainage; Drainage fittings in flat roofs, balconies or the like
- E04D13/064—Gutters
- E04D13/068—Means for fastening gutter parts together
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
TITLE: SEALING SYSTEM FOR EAVESTROUGHING
ABSTRACT OF THE DISCLOSURE
The present application discloses a method of molding a gasket on a plastic eavestrough connector comprising the steps of heating a flexible plastic material to a molten state and pressurizing molten plastic material for injection into a mold; locating and supporting a plastic eavestrough connector for receiving the molten plastic material: positioning a male mold component for movement between a clear position and a fill position within a located connector; injecting the molten plastic material under pressure into cavities defined by the male mold in the fill position and such located connector; maintaining the temperature of the injected material above approximately 250 degree fahrenheit until the cavities have been filled cooling the injected molded material and connector to a temperature below the set temperature of the flexible plastic material; moving the male mold to a clear position and ejecting the connector with the formed gasket thereon. The male mold includes a number of channels defining in combination with a connector the shape of the gasket. In particular, an eavestrough connector having a molded gasket thereon is taught which utlizes three sealing ribs which each provide a wiper like seal with a received portion of eavestroughing. The fitting has a body having an interior surface in the shape for receiving the eavestrough, a gasket on the interior surface of the body having a thin base portion and a pair of generally parallel sealing ribs extending therefrom and of reducing cross section and an intermediate distribution rib of reduced thickness relative to the sealing ribs.
ABSTRACT OF THE DISCLOSURE
The present application discloses a method of molding a gasket on a plastic eavestrough connector comprising the steps of heating a flexible plastic material to a molten state and pressurizing molten plastic material for injection into a mold; locating and supporting a plastic eavestrough connector for receiving the molten plastic material: positioning a male mold component for movement between a clear position and a fill position within a located connector; injecting the molten plastic material under pressure into cavities defined by the male mold in the fill position and such located connector; maintaining the temperature of the injected material above approximately 250 degree fahrenheit until the cavities have been filled cooling the injected molded material and connector to a temperature below the set temperature of the flexible plastic material; moving the male mold to a clear position and ejecting the connector with the formed gasket thereon. The male mold includes a number of channels defining in combination with a connector the shape of the gasket. In particular, an eavestrough connector having a molded gasket thereon is taught which utlizes three sealing ribs which each provide a wiper like seal with a received portion of eavestroughing. The fitting has a body having an interior surface in the shape for receiving the eavestrough, a gasket on the interior surface of the body having a thin base portion and a pair of generally parallel sealing ribs extending therefrom and of reducing cross section and an intermediate distribution rib of reduced thickness relative to the sealing ribs.
Description
3~32~L
FIELD OF THE INVENTION
The present invention relates to a method of molding a gasket directly on a plastic eavestrough fitting and an eavestrough ~itting having a gasket molded thereon.
BACKGROUND OF THE INVENTION
In the past, a number of systems have been proposed for interconnecting lengths of plastic or metal eavestrough by receiving the eavestrough in connectors having gasket members. The prior practise included gluing foaM like gaskets directly on the connectors which gaskets were compressed when a length of eavestrough was received in the connector. Other systems included the gluing of connectors and eavestrough, thereby providing a permanent bond between the components. These types of systems are commonly used with plastic eavestrough connectors and plastic eavestroughing all o~ which are prone to changing characteristics with temperatures.
This is particularly troublesome in North America where the extreme high temperatures of summer and the extreme low temperatures of winter cause significant expansion and contraction o~ the components and the seal must assure that the eavestrough maintains its sealing engagement within the connector. Furthermore, eavestroughing is most commonly made by extrusion when the eavestrough is a plastic and made of rolled steel when made of metal, and both techniques requires significant tolerance variations which can cause problems with respect to maintaining the sealing engagement with varying climatic conditions. Furthermore, the eavestroughing, whether made of plastic or metal, tends to have a fairly deformable lower portion which thereby causes a reduced sealing pressure in the center of the eavestroughing. Most of the gasket members that are 3~2~
secured to the eavestrough connector are themselves extruded and therefore it is very difficult to provide a gasket member having varying height across the connector. By molding the gasket member directly on the connector, the cross section of the gasket can be customized to assure an effective seal with the lower surface of the eavestrough. In addition, this effective seal allows the cross section of the eavestroughing to include straight segments interconnected by curved radii which are more pleasing to the eye as compared with traditional semi-circular eavestroughingO It can be appreciated that the transition from one straight segment to a second segment, even if made by use of a radius, does provide some difficulty assuring an effective seal is provided, however, this problem is overcome with the present method and product.
Although the broad concept of injection molding a component on a previously molded component is taught in the prior art as illustrated by:
United States Patent 4,115,506 Canadian Patent 668,709 Canadian Patent 768,052 Canadian Patent 1,032,32û and Canadian Patent 1,070,071 25 it is difficult to mold a gasket member on a plastic connector where one is relying on the physical bonding o~
the gasket to the connector to maintain the gasket in sealing engagement with the connector. It has been found that certain temperature restrictions are required in order to provide a secure physical bonding of the gasket to the connector.
SUMMARY OF THE INVENTION
A method of forming a gasket on a plastic eavestrough connector according to the present invention 3~
comprises heating a flexible resilient plastic gasket material to a molten state and pressurizing the molten plastic material for injection into a mold, locating and supporting a plastic eavestrough connector for receiving the molten plastlc material, positioning a male mold component for movement between a clear position and a fill position within the located connector; the male mold defining in the fill position the shape of the gaskets by cavities in the surface oF the male mold opposite and essentially closed by the interior surface of such located connector, injecting the molten plastic material under pressure into the cavities defined by the male mold in the fill position and such located connector, maintaining the temperature of the injected material above approximately 25G degrees fahrenheit until the cavities have been filled, cooling the injected molded material to a temperature below the set temperature of the flexible material, moving the male mold to the clear position and ejecting the connector with the formed gasket thereon from the located and supported position.
An eavestroughins fitting for receiving and sealingly engaging the end of a length of eavestrough on the lower surface of the eavestrough according to the present invention has a body portion having an interior of a shape for receiving the eavestrough, a gasket on the interior surface of the body having a thin base portion and a pair of generally parallel sealing ribs extending therefrom and a distribution rib of reducing cross section intermediate and of reduced thickness relative to the sealing ribs. The sealing ribs are generally the same height and each rib is bendable about the longitudinal axis of the gasket to form a wiper like seal with a received eavestrough. The fitting includes means for retaining a received eavestrough, which is in ~3~
conbination with the gasket defines an interference fit for receiving such eavestrough causing bending of the ribs to define three wiper like seals on the lower surface of the received eavestrough. The elasticity of the ribs maintains the wiper seals with changing climatic conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown in the drawings wherein:
Figure 1 is a perspective view of an endcap eavestrough connector;
Figure 2 is a side elevation of the eavestrough connector of Figure l;
Figure 3 is a partial schematic view of an eavestrough end connector and a male mold being moved from the clear position to a position within the connector;
Figure 4 shows the eavestrough connector of Figure 3 and the male mold located in the fill position;
Figure 5 is a cross section through the center of the eavestrough connector;
Figure 6 is a partial perspective view of an eavestrough about to be inserted in a eavestrough end connector, and Figure 7 is a section view showing an eavestrough inserted within an eavestrouyh end connector.
DETAILED DESCRIPTION OF THE PREFERRED EMB~DIMENTS
The shape of the plastic endcap 2 shown throughout the drawings is only representative of the different type of eavestrough connectors necessary for a rain ware system. It can be appreciated that the term eavestrough connector would include center drops which would include gasket members at either end thereof each for sealingly engaging a length of eavestroughing, mitre ~5 connectors for going about corners, joiners used to interconnect two lengths of eavestroughing, as well as end drops. The type of eavestrough connector is generally used in the horizontal segment of the rain ware system, although if necessary it could also apply to the downspouts and the connectors therefor.
The end connector 2 has a body portion 4 of an unplasticized poly-vinyl chloride material and is fairly rigid relative to the flexible poly~vinyl chloride gasket material used in forming the gasket generally shown as 6. This gasket member has a pair of sealing ribs 12 extending in the length of the gasket as well as a distribution rib 14 generally centered between the sealing ribs 12. The body of the connector 4 has a generally flat central segment 20 having two radii transitions 18 one either side of the central segment for interconnecting the angled side walls 22. As can be seen, the gasket member 6 extends across the central segment over the radius transitions and upwardly along the angled side walls 22. The endcap also includes an end wall 10 which is integral with the central segment and the side walls. Adjacent the top end of the connector and either side of the center line of the connector are two eavestrough retaining portions 6 which include a downwardly extending lip 8. The eavestrough may be inserted sliding it into the connector as generally shuwn in Figure 6, or may be first inserted within one of the connectors 6 and snapped beneath the other one by applying sufficient pressure.
The central distribution rib 14 projects above the height of the ceiling ribs 12 adjacent each radius transition 18 and assures an effective seal with the eavestroughing at the radius transition point. The distribution rib 14 is generally of reduced thickness ~i~33~32~a relative to the thickness of sealing ribs 12 and easily bends to provide the effective seal without disturbing the seal between the eavestroughing and the individual sealing ribs 1~. In this way, the middle distribution rib provides a further seal with an inserted eavestrough without appreciably effecting the sealing action of the sealing ribs and the eavestrough. In addition, the shape and characteristics of the distribution rib complement the sealing provided by the sealing ribs.
Some care must be exercised in the method of molding the gasket member directly on the unplastici~ed poly~vinyl chloride connector in order to assure an effective bonding of the gasket member to the connector.
Defects in the gasket caused by poor bonding of the gasket member to the connector or incomplete fill of the cavities, resulting in incomplete gaskets, can cause considerable problems with respect to manufacturing rejects and product quality. It has been found that during the injection molding process, the temperature of the gasket material should be maintained above approximately 250 degrees fahrenheit until the cavities have been filled and this will assure both a complete fill of the cavities as well as a positive physical bond of the gasket to the connector. In order to maintain this temperature and in order to reduce the set times, it has been found that the distribution rib 14 which is lnterconnected to the sealing ribs 12 by the thin base portion 11, results in a more balanced fill rate and fill quantity in each of the sealing ribs 12, whereby the cavities are completely filled and the material is at an appropriate temperature to assure good adhesion of the gasket member to the connector. If only two ribs are provided, one can become plugged and the fill rate is effected whereby even if the material eventually does fill the cavity due to interconnecting base portion and the pressure of injection, which in this case is less than approximately lO,OOû psi, the material is no longer at a temperature where strong adhesion is assured.
Furthermore in other cases, it has been found that incomplete fills occur particularly adjacent the upper end of the cavities. These problems are alleviated by forming the distribution rib.
Turning to Figure 3 and 4, it can be seen that a collapsible male mold generally designated as 30 includes an interior wedge member 34 having a cavity on the lower surface thereof generally designated as 3~ for partially defining the gasket. This cavity 36 is continued on the side portions 32 of the male mold. By moving the collapsible mold down generally by a press and inserting it within a preformed eavestrough connector properly supported by member 42 shown in Figure 4, the cavities 36 of the male mold define the upper surface of the gasket member. These cavities are effectively closed by the interior surface of the body of the connector 4. In addition, a number of cooling paths have been schematically as 38 in the male mold and cooling fluid is continuously circulated through the male mold. This is required in order to dissipate the heat of the gasket member and to reduce the set time required. However it can be appreciated, this process is in direct contradiction to the process of maintaining the temperature of the gasket material above approximately 250 degrees fahrenheit until the entire cavity has been formed in order to assure good adhesion of the gasket member to the connector. However, it has been found if the material is injected at a pressure between approximately 5,000 and 10,000 psi, at a temperature of approximately 340 degrees fahrenheit that the cavities ~z~
are completely filled and the gasket material is at a temperature of at least 250 degrees fahrenheit after the filling operation has been completed. The heat of the gasket is then dissipated into the relatively cold male mold thereby reducing the temperature of the gasket material to a set temperature of about 150 degrees. The male mold is schematically illustrated in Figure 3 and in Figure 4 parallel bars 40 have been provided ~hich show the distribution of the pressure exerted by the press which initially expands the male mold within the connector and causes the parallel bars to bottom out on the support 42. The hydraulic press operates at approximately 75 tons and the plastic connector could not withstand this pressure without deforming to a point that it is no longer useful. However, the connector is exposed to the in;tial pressure and causes locali~ed deformation generally identified as 15 either side of the gasket member 6, as shown in Figure 5, and this localized deformation assists in the sealing of the cavities of the male mold thereby assuring the gasket does not leak out of the cavities during the injection molding of the gasket. The parallel bars 40 assure that only a predetermined amount of localized deformation occurs which is not of a magnitude to completely deform the connector.
It is preferred that the base 11 of the gasket member be relatively thin and preferrably at about 15 thousandths of an inch. It has been found that the sealing ribs adjacent the upper surface of the gasket member are preferrably about fifty thousandths of an inch tapering to an upper edge of about 30 thousandths of an inch. It has also been found that the distribution rib 14 is preferrably thinner in cross section than the sealing ribs. The thin base member 11 interconnects the 33~2~
various ribs and the injected material quickly fills the cavities.
In Figure 6 ~he portion of eavestrough 50 is shown about to be slideably inserted within an eaves-trough connector 4 indicated by arrow 52. The insertionof this eavestrough will cause a bending of the individual ribs about the longitudinal axis of the gasket member to form a wiper like seal between the ribs and the lower surface of the eavestrough. This seal is in contradiction to the compression type seals used in other systems. The resiliency of the ribs maintains the individual wiper seals with changing climatic conditions which could cause expansion or contraction oF the eavestrough and connector and resulting in movement of the eavestrough within the connector.
Therefore according to the preferred embodiment of the invention, it has been found that a fle~ible poly-vinyl chloride gasket material can be injection molded on a unplasticized poly-vinyl eavestrough connector in a manner to effectively bond the gasket to the connector by injecting the gasket material at a temperature of about 340 degrees fahrenheit and assuring the gasket material is maintained at a temperature of above approximately 250 degrees fahrenheit during the filling of the cavities. After this has been completed, further cooling of the gasket and connector occurs and the part can be ejected after the gasket has reached a temperature of about 150 degrees.
In addition, it has been found that the injection pressure should be in the range of about 5,000 to 10,000 psi and the use of a third rib located between the two sealing ribs all of which are interconnected by a thin base portion provides an effective way of assuring a complete fill of the cavities and good adhesion of the g 3B;~
gasket to the connector.
Although various preferred embodiments of the present inven-tion have been described herein in detail, it will be understood by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
FIELD OF THE INVENTION
The present invention relates to a method of molding a gasket directly on a plastic eavestrough fitting and an eavestrough ~itting having a gasket molded thereon.
BACKGROUND OF THE INVENTION
In the past, a number of systems have been proposed for interconnecting lengths of plastic or metal eavestrough by receiving the eavestrough in connectors having gasket members. The prior practise included gluing foaM like gaskets directly on the connectors which gaskets were compressed when a length of eavestrough was received in the connector. Other systems included the gluing of connectors and eavestrough, thereby providing a permanent bond between the components. These types of systems are commonly used with plastic eavestrough connectors and plastic eavestroughing all o~ which are prone to changing characteristics with temperatures.
This is particularly troublesome in North America where the extreme high temperatures of summer and the extreme low temperatures of winter cause significant expansion and contraction o~ the components and the seal must assure that the eavestrough maintains its sealing engagement within the connector. Furthermore, eavestroughing is most commonly made by extrusion when the eavestrough is a plastic and made of rolled steel when made of metal, and both techniques requires significant tolerance variations which can cause problems with respect to maintaining the sealing engagement with varying climatic conditions. Furthermore, the eavestroughing, whether made of plastic or metal, tends to have a fairly deformable lower portion which thereby causes a reduced sealing pressure in the center of the eavestroughing. Most of the gasket members that are 3~2~
secured to the eavestrough connector are themselves extruded and therefore it is very difficult to provide a gasket member having varying height across the connector. By molding the gasket member directly on the connector, the cross section of the gasket can be customized to assure an effective seal with the lower surface of the eavestrough. In addition, this effective seal allows the cross section of the eavestroughing to include straight segments interconnected by curved radii which are more pleasing to the eye as compared with traditional semi-circular eavestroughingO It can be appreciated that the transition from one straight segment to a second segment, even if made by use of a radius, does provide some difficulty assuring an effective seal is provided, however, this problem is overcome with the present method and product.
Although the broad concept of injection molding a component on a previously molded component is taught in the prior art as illustrated by:
United States Patent 4,115,506 Canadian Patent 668,709 Canadian Patent 768,052 Canadian Patent 1,032,32û and Canadian Patent 1,070,071 25 it is difficult to mold a gasket member on a plastic connector where one is relying on the physical bonding o~
the gasket to the connector to maintain the gasket in sealing engagement with the connector. It has been found that certain temperature restrictions are required in order to provide a secure physical bonding of the gasket to the connector.
SUMMARY OF THE INVENTION
A method of forming a gasket on a plastic eavestrough connector according to the present invention 3~
comprises heating a flexible resilient plastic gasket material to a molten state and pressurizing the molten plastic material for injection into a mold, locating and supporting a plastic eavestrough connector for receiving the molten plastlc material, positioning a male mold component for movement between a clear position and a fill position within the located connector; the male mold defining in the fill position the shape of the gaskets by cavities in the surface oF the male mold opposite and essentially closed by the interior surface of such located connector, injecting the molten plastic material under pressure into the cavities defined by the male mold in the fill position and such located connector, maintaining the temperature of the injected material above approximately 25G degrees fahrenheit until the cavities have been filled, cooling the injected molded material to a temperature below the set temperature of the flexible material, moving the male mold to the clear position and ejecting the connector with the formed gasket thereon from the located and supported position.
An eavestroughins fitting for receiving and sealingly engaging the end of a length of eavestrough on the lower surface of the eavestrough according to the present invention has a body portion having an interior of a shape for receiving the eavestrough, a gasket on the interior surface of the body having a thin base portion and a pair of generally parallel sealing ribs extending therefrom and a distribution rib of reducing cross section intermediate and of reduced thickness relative to the sealing ribs. The sealing ribs are generally the same height and each rib is bendable about the longitudinal axis of the gasket to form a wiper like seal with a received eavestrough. The fitting includes means for retaining a received eavestrough, which is in ~3~
conbination with the gasket defines an interference fit for receiving such eavestrough causing bending of the ribs to define three wiper like seals on the lower surface of the received eavestrough. The elasticity of the ribs maintains the wiper seals with changing climatic conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown in the drawings wherein:
Figure 1 is a perspective view of an endcap eavestrough connector;
Figure 2 is a side elevation of the eavestrough connector of Figure l;
Figure 3 is a partial schematic view of an eavestrough end connector and a male mold being moved from the clear position to a position within the connector;
Figure 4 shows the eavestrough connector of Figure 3 and the male mold located in the fill position;
Figure 5 is a cross section through the center of the eavestrough connector;
Figure 6 is a partial perspective view of an eavestrough about to be inserted in a eavestrough end connector, and Figure 7 is a section view showing an eavestrough inserted within an eavestrouyh end connector.
DETAILED DESCRIPTION OF THE PREFERRED EMB~DIMENTS
The shape of the plastic endcap 2 shown throughout the drawings is only representative of the different type of eavestrough connectors necessary for a rain ware system. It can be appreciated that the term eavestrough connector would include center drops which would include gasket members at either end thereof each for sealingly engaging a length of eavestroughing, mitre ~5 connectors for going about corners, joiners used to interconnect two lengths of eavestroughing, as well as end drops. The type of eavestrough connector is generally used in the horizontal segment of the rain ware system, although if necessary it could also apply to the downspouts and the connectors therefor.
The end connector 2 has a body portion 4 of an unplasticized poly-vinyl chloride material and is fairly rigid relative to the flexible poly~vinyl chloride gasket material used in forming the gasket generally shown as 6. This gasket member has a pair of sealing ribs 12 extending in the length of the gasket as well as a distribution rib 14 generally centered between the sealing ribs 12. The body of the connector 4 has a generally flat central segment 20 having two radii transitions 18 one either side of the central segment for interconnecting the angled side walls 22. As can be seen, the gasket member 6 extends across the central segment over the radius transitions and upwardly along the angled side walls 22. The endcap also includes an end wall 10 which is integral with the central segment and the side walls. Adjacent the top end of the connector and either side of the center line of the connector are two eavestrough retaining portions 6 which include a downwardly extending lip 8. The eavestrough may be inserted sliding it into the connector as generally shuwn in Figure 6, or may be first inserted within one of the connectors 6 and snapped beneath the other one by applying sufficient pressure.
The central distribution rib 14 projects above the height of the ceiling ribs 12 adjacent each radius transition 18 and assures an effective seal with the eavestroughing at the radius transition point. The distribution rib 14 is generally of reduced thickness ~i~33~32~a relative to the thickness of sealing ribs 12 and easily bends to provide the effective seal without disturbing the seal between the eavestroughing and the individual sealing ribs 1~. In this way, the middle distribution rib provides a further seal with an inserted eavestrough without appreciably effecting the sealing action of the sealing ribs and the eavestrough. In addition, the shape and characteristics of the distribution rib complement the sealing provided by the sealing ribs.
Some care must be exercised in the method of molding the gasket member directly on the unplastici~ed poly~vinyl chloride connector in order to assure an effective bonding of the gasket member to the connector.
Defects in the gasket caused by poor bonding of the gasket member to the connector or incomplete fill of the cavities, resulting in incomplete gaskets, can cause considerable problems with respect to manufacturing rejects and product quality. It has been found that during the injection molding process, the temperature of the gasket material should be maintained above approximately 250 degrees fahrenheit until the cavities have been filled and this will assure both a complete fill of the cavities as well as a positive physical bond of the gasket to the connector. In order to maintain this temperature and in order to reduce the set times, it has been found that the distribution rib 14 which is lnterconnected to the sealing ribs 12 by the thin base portion 11, results in a more balanced fill rate and fill quantity in each of the sealing ribs 12, whereby the cavities are completely filled and the material is at an appropriate temperature to assure good adhesion of the gasket member to the connector. If only two ribs are provided, one can become plugged and the fill rate is effected whereby even if the material eventually does fill the cavity due to interconnecting base portion and the pressure of injection, which in this case is less than approximately lO,OOû psi, the material is no longer at a temperature where strong adhesion is assured.
Furthermore in other cases, it has been found that incomplete fills occur particularly adjacent the upper end of the cavities. These problems are alleviated by forming the distribution rib.
Turning to Figure 3 and 4, it can be seen that a collapsible male mold generally designated as 30 includes an interior wedge member 34 having a cavity on the lower surface thereof generally designated as 3~ for partially defining the gasket. This cavity 36 is continued on the side portions 32 of the male mold. By moving the collapsible mold down generally by a press and inserting it within a preformed eavestrough connector properly supported by member 42 shown in Figure 4, the cavities 36 of the male mold define the upper surface of the gasket member. These cavities are effectively closed by the interior surface of the body of the connector 4. In addition, a number of cooling paths have been schematically as 38 in the male mold and cooling fluid is continuously circulated through the male mold. This is required in order to dissipate the heat of the gasket member and to reduce the set time required. However it can be appreciated, this process is in direct contradiction to the process of maintaining the temperature of the gasket material above approximately 250 degrees fahrenheit until the entire cavity has been formed in order to assure good adhesion of the gasket member to the connector. However, it has been found if the material is injected at a pressure between approximately 5,000 and 10,000 psi, at a temperature of approximately 340 degrees fahrenheit that the cavities ~z~
are completely filled and the gasket material is at a temperature of at least 250 degrees fahrenheit after the filling operation has been completed. The heat of the gasket is then dissipated into the relatively cold male mold thereby reducing the temperature of the gasket material to a set temperature of about 150 degrees. The male mold is schematically illustrated in Figure 3 and in Figure 4 parallel bars 40 have been provided ~hich show the distribution of the pressure exerted by the press which initially expands the male mold within the connector and causes the parallel bars to bottom out on the support 42. The hydraulic press operates at approximately 75 tons and the plastic connector could not withstand this pressure without deforming to a point that it is no longer useful. However, the connector is exposed to the in;tial pressure and causes locali~ed deformation generally identified as 15 either side of the gasket member 6, as shown in Figure 5, and this localized deformation assists in the sealing of the cavities of the male mold thereby assuring the gasket does not leak out of the cavities during the injection molding of the gasket. The parallel bars 40 assure that only a predetermined amount of localized deformation occurs which is not of a magnitude to completely deform the connector.
It is preferred that the base 11 of the gasket member be relatively thin and preferrably at about 15 thousandths of an inch. It has been found that the sealing ribs adjacent the upper surface of the gasket member are preferrably about fifty thousandths of an inch tapering to an upper edge of about 30 thousandths of an inch. It has also been found that the distribution rib 14 is preferrably thinner in cross section than the sealing ribs. The thin base member 11 interconnects the 33~2~
various ribs and the injected material quickly fills the cavities.
In Figure 6 ~he portion of eavestrough 50 is shown about to be slideably inserted within an eaves-trough connector 4 indicated by arrow 52. The insertionof this eavestrough will cause a bending of the individual ribs about the longitudinal axis of the gasket member to form a wiper like seal between the ribs and the lower surface of the eavestrough. This seal is in contradiction to the compression type seals used in other systems. The resiliency of the ribs maintains the individual wiper seals with changing climatic conditions which could cause expansion or contraction oF the eavestrough and connector and resulting in movement of the eavestrough within the connector.
Therefore according to the preferred embodiment of the invention, it has been found that a fle~ible poly-vinyl chloride gasket material can be injection molded on a unplasticized poly-vinyl eavestrough connector in a manner to effectively bond the gasket to the connector by injecting the gasket material at a temperature of about 340 degrees fahrenheit and assuring the gasket material is maintained at a temperature of above approximately 250 degrees fahrenheit during the filling of the cavities. After this has been completed, further cooling of the gasket and connector occurs and the part can be ejected after the gasket has reached a temperature of about 150 degrees.
In addition, it has been found that the injection pressure should be in the range of about 5,000 to 10,000 psi and the use of a third rib located between the two sealing ribs all of which are interconnected by a thin base portion provides an effective way of assuring a complete fill of the cavities and good adhesion of the g 3B;~
gasket to the connector.
Although various preferred embodiments of the present inven-tion have been described herein in detail, it will be understood by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
Claims (34)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of forming a gasket on an unplasticized poly-vinyl chloride eavestrough connector comprising heating a flexible poly-vinyl chloride gasket material to a temperature of about 340 degrees fahrenheit and pressurizing the heated poly-vinyl chloride for injection into a mold, locating and supporting a rigid poly-vinyl chloride connector for receiving the heated poly-vinyl chloride material, positioning a collapsible male mold component for movement between a clear position and a fill position within a located rigid poly-vinyl chloride connector, the male collapsible mold in combination with the interior surface of the located connector defining the shape of the gasket by cavities on the surface of the male mold closed by the interior surface of the connector when said mold is in the fill position, injecting the heated poly-vinyl chloride gasket material under pressure into the cavities defined by the male mold in the fill position and a located poly-vinyl chloride connector, maintaining the temperature of the injected poly-vinyl chloride gasket material above approximately 250 degrees fahrenheit until the cavities have been filled, cooling the injected molded material and rigid poly-vinyl chloride connector to a temperature below the set temperature of the poly-vinyl chloride gasket material, moving said male mold to the clear position and ejecting the rigid poly-vinyl chloride connector with a formed gasket thereon.
2. A method as claimed in claim 1 wherein the injected gasket material is cooled by dissipating heat into the collapsible male mold.
3. A method as claimed in claim 1 or 2 including water cooling the male mold.
4. A method as claimed in claim 1 including continuously providing a flow of cooling fluid to said male mold and providing a sufficient flow rate of injected molded poly-vinyl chloride material to fill the extremities of the cavities prior to the injected material cooling to a temperature below about 250 degrees fahrenheit.
5. A method as claimed in claim 1 including providing cavities which define a gasket having a cross section including a wide thin base for direct securement to the corresponding surface of said poly-vinyl chloride connector, a pair of sealing ribs adjacent the outer edge of said thin base and a central distribution rib between said sealing ribs and in communication with said sealing ribs along essentially the length thereof by said thin base, said distribution rib providing a flow path for the heated poly-vinyl chloride gasket material which provides a complete fill of the cavities defining the gasket.
6. A method as claimed in claim 2, 4 or 5 including providing only one fill port for each gasket generally centrally located in the length of the gasket.
7. A method as claimed in claim 2, 4 or 5 including injecting the heated poly-vinyl chloride gasket material at a fill pressure of less than 10,000 psi.
8. A method as claimed in claim 1, 2 or 5 including providing a fill pressure of the material to be injected in the range of about 5,000 psi to 10,000 psi.
9. A method as claimed in claim 1, 2 or 5 wherein the connector and gasket are cooled sufficiently such that the temperature of the gasket is less than about 150 degrees fahrenheit prior to movement of said male mold to the clear position.
10. A method of forming a gasket on a rigid poly-vinyl chloride connector to receive and sealing engage a piece of plastic eavestrough comprising heating a flexible poly-vinyl chloride gasket material to a temperature of about 340 degrees fahrenheit and pressurizing the material for injection onto the connector for forming of the gasket, supporting and positioning a rigid poly-vinyl chloride component for reception of the heated gasket material, moving a male mold having cavities on the surface thereof into engagement with the supported component to thereby define between the mold and the component the cross section and length of the gasket member to be formed, injecting the heated soft poly-vinyl chloride material under pressure into the cavities, maintaining the temperature of the injected poly-vinyl chloride material above approximately 250 degrees fahrenheit during filling of the cavities, cooling the injected poly-vinyl chloride material and connector to a temperature of the injected poly-vinyl chloride gasket material of less than about 150 degrees fahrenheit, and removing said male mold.
11. A method as claimed in claim 10 including maintaining the temperature of the injected gasket material in the range of about 250 degrees fahrenheit to about 280 degrees fahrenheit until the cavities have been filled.
12. A method as claimed in claim 10 or 11 including maintaining the pressure of the material about to be injected in the cavities below about 10,000 psi.
13. A method as claimed in claim 10 or 11 including circulating a cooling fluid through the male mold to reduce the set time required to cool the injected material to about 150 degrees fahrenheit while assuring the temperature of the injected material remains above approximately 250 degrees fahrenheit until the cavity has been completely filled.
14. A method as claimed in claim 10 or 11 wherein the cavities of the male mold and the connector define an elongate gasket having a thin base portion with a pair of sealing ribs either side thereof and a central thinner distribution rib located between said sealing ribs and generally of the same height thereof to cause a complete fill of the cavities defining the gasket.
15. A method as claimed in claim 1, including providing sufficient pressure on said male mold to provide localized deformation of the poly-vinyl chloride component either side of the location of the gasket to effectively provide a seal between the unplasticized poly-vinyl chloride component and the male mold.
16. A method as claimed in claim 15 including means for limiting the pressure exerted on the rigid poly-vinyl chloride component after a predetermined movement of said male component.
17. A method as claimed in claim 16 wherein said limiting means include parallel bars which distribute the pressure exerted on the male mold to a structure other than the plastic connector.
18. A method as claimed in claim 15, 16 or 17 wherein the pressure exerted on the male mold is created by a press which exerts approximately 75 tons pressure.
19. An eavestrough fitting for receiving end of a length of an eavestrough and sealingly engaging the received lower surface of the eavestrough, said fitting having a body having interior surface of a shape for receiving such eavestrough, a gasket physically bonded on the interior surface of said body, said gasket having a thin base portion and a pair of generally parallel sealing ribs extending therefrom and of reducing cross section, and an intermediate distribution rib of reduced thickness relative to said sealing ribs, said ribs being generally of the same height and each rib being bendable to either side of the longitudinal axis of the gasket to form a wiper like seal with a received eavestrough, said fitting including means for retaining a received eavestrough, said means for retaining and said gasket defining an interference fit for receiving such eavestrough causing bending of said ribs to define three wiper like seals on the lower surface of such received eavestrough, the elasticity of said ribs maintaining the wiper seals with changing climatic conditions.
20. A fitting as claimed in claim 19 including varying the height of said ribs in the length thereof to more closely correspond to the shape of the lower periphery of such eavestroughing.
21. A fitting as claimed in claim 19 or 20 wherein said gasket is injection molded on said fitting.
22. A fitting as claimed in claim 19 wherein said gasket is injection molded on said fitting in a manner to physically deform said fitting on the interior surface thereof, said gasket being made of flexible poly-vinyl chloride material.
23. A fitting as claimed in claim 22 wherein said body is injection molded and made of unplasticized poly-vinyl chloride material.
24. A fitting as claimed in claim 19 wherein said fitting is generally symmetrical in cross section and has an interior surface having a generally flat central segment, radii transitions either side of said central segment interconnecting said central segment and angled side wall portions, said distribution rib being of a height greater than said sealing ribs adjacent said radii transitions.
25. A fitting as claimed in claim 24 wherein said sealing ribs are of varying height across said central segment.
26. A fitting as claimed in claim 19 wherein said gasket is injection molded on said body and the height of said ribs vary in the length of said gasket.
27. A fitting as claimed in claim 19 wherein said base of said gasket is physically bonded to said body and is of a thickness of about 15 thousandths of an inch.
28. A fitting as claimed in claim 27 wherein said sealing ribs taper to a thickness of about 35 thousandths of an inch.
29. A fitting as claimed in claim 28 wherein said sealing ribs are of a thickness adjacent the base of about 50 thousandths of an inch.
30. A method of forming a gasket on a plastic eavestrough connector comprising heating a flexible resilient plastic gasket material to a molten state and pressurizing the molten plastic material for injection into a mold;
locating and supporting a plastic eavestrough connector for receiving the molten plastic material, positioning a male mold component for movement between a clear position and a fill position within such located connector, the male mold defining in the fill position the shape of the gasket by cavities on the surface of the male mold opposite and essentially closed by the interior surface of such located connector, injecting the molten plastic material under pressure into the cavities defined by the male mold in the fill position and such located connector, maintaining the temperature of the injected material above approximately 250 degrees fahrenheit until the cavities have been filled, cooling the injected molded material and connector to a temperature below the set temperature of the flexible plastic material, moving said male mold to the clear position, and ejecting the connector with the formed gasket thereon.
locating and supporting a plastic eavestrough connector for receiving the molten plastic material, positioning a male mold component for movement between a clear position and a fill position within such located connector, the male mold defining in the fill position the shape of the gasket by cavities on the surface of the male mold opposite and essentially closed by the interior surface of such located connector, injecting the molten plastic material under pressure into the cavities defined by the male mold in the fill position and such located connector, maintaining the temperature of the injected material above approximately 250 degrees fahrenheit until the cavities have been filled, cooling the injected molded material and connector to a temperature below the set temperature of the flexible plastic material, moving said male mold to the clear position, and ejecting the connector with the formed gasket thereon.
31. A method as claimed in claim 1 wherein said connector and said gasket are cooled by dissipating heat into the collapsible male mold.
32. A method as claimed in claim 1 or 2 including water cooling the male mold.
33. A method as claimed in claim 1 including continuously providing a flow of cooling fluid to said male mold and providing a sufficient flow rate of injected molded poly-vinyl chloride material to fill the extremities of the cavities prior to any of the injected material cooling to a temperature below about 250 degrees fahrenheit.
34. A method as claimed in claim 1 including providing cavities which define a gasket having a cross section including a wide thin base for direct securement to the corresponding surface of the connector, a pair of sealing ribs adjacent the outer edge of said thin base and a central distribution rib between said sealing ribs and in communication with said sealing ribs along essentially the length thereof by said thin base, said distribution rib providing a flow path for the molten plastic material which provides a complete fill of the cavities with the molten material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000438598A CA1193824A (en) | 1983-10-07 | 1983-10-07 | Sealing system for eavestroughing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000438598A CA1193824A (en) | 1983-10-07 | 1983-10-07 | Sealing system for eavestroughing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1193824A true CA1193824A (en) | 1985-09-24 |
Family
ID=4126246
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000438598A Expired CA1193824A (en) | 1983-10-07 | 1983-10-07 | Sealing system for eavestroughing |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1193824A (en) |
-
1983
- 1983-10-07 CA CA000438598A patent/CA1193824A/en not_active Expired
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