CA1110022A - Method of blow molding an all plastic drum and compression molding a projection theron - Google Patents
Method of blow molding an all plastic drum and compression molding a projection theronInfo
- Publication number
- CA1110022A CA1110022A CA307,776A CA307776A CA1110022A CA 1110022 A CA1110022 A CA 1110022A CA 307776 A CA307776 A CA 307776A CA 1110022 A CA1110022 A CA 1110022A
- Authority
- CA
- Canada
- Prior art keywords
- drum
- parison
- compression
- projections
- blow
- 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
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D25/00—Details of other kinds or types of rigid or semi-rigid containers
- B65D25/20—External fittings
- B65D25/22—External fittings for facilitating lifting or suspending of containers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D1/00—Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material
- B65D1/12—Cans, casks, barrels, or drums
- B65D1/14—Cans, casks, barrels, or drums characterised by shape
- B65D1/16—Cans, casks, barrels, or drums characterised by shape of curved cross-section, e.g. cylindrical
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Ceramic Engineering (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
Abstract
METHOD OF BLOW MOLDING AN ALL PLASTIC DRUM
AND COMPRESSION MOLDING A PROJECTION THEREON
ABSTRACT OF THE DISCLOSURE
An all plastic tubular drum is blow molded into the selected configuration from an extruded parison. The parison is provided with at least two spaced circumferentially ex-tending thickened sections. These thickened sections are captured in a compression mold cavity during the blow molding cycle. Thereafter the captured thickened sections are com-pression molded into outwardly extending projections, under-cuts, reinforcing gussets, or the like.
AND COMPRESSION MOLDING A PROJECTION THEREON
ABSTRACT OF THE DISCLOSURE
An all plastic tubular drum is blow molded into the selected configuration from an extruded parison. The parison is provided with at least two spaced circumferentially ex-tending thickened sections. These thickened sections are captured in a compression mold cavity during the blow molding cycle. Thereafter the captured thickened sections are com-pression molded into outwardly extending projections, under-cuts, reinforcing gussets, or the like.
Description
1~1002Z
The present invention relates to the moulding of plastic drums.
The present invention is particularly directed to the production of a plastic drum disclosed in copending application No. 307,777 filed on even date herewith and entitled All Plastic Blow Molded Drum.
In the above referenced copending application, an all plastic blow molded drum is disciosed and includes a tubular out-wardly bilged body having an integral upper and bottom closed end each provided with outwardly extending ribs arranged and dimen-sioned to permit stacking of one drum on top of another similar drum. The upper rib is interrupted with a sealable drain opening disposed in one of the interruptions and a vent opening disposed in the other of such interruptions. A radial circumferentially extending rib on the drum body is located near the upper end and bottom end with each rib provided with a laterally extending flange extending in the direction of the neighboring end, thereby defining a recess for accommodating surfaces of a drum moving device such as a hook or parrot beak lifting device. The radial ribs with lateral flange serve as rolling hoops and extend out-wardly in a radial direction an amount substantially the same as that of the bilge of the tubular body side wall whereby the cen-tral portions of neighboring drums can touch one another in transport without the upper and lower flanges hooking over or on each other.
~?~
The present invention provides a method of molding the foregoing all plastic drum.
The present invention also provides a method of blow molding an all plastic drum and at the same time form an outwardly extending projection thereon by a compression molding technique.
According to the present invention therefore there is provided a method of moulding a plastic drum having at least one outwardly extending projection comprising the steps of: extruding a tubular parison of resin material having a predetermined wall thickness with at least one section thereof having an additional amount of resin of increased thickness for formation of each pro-jection and at the same time assure a predetermined wall thick-ness of the drum adjacent each projection no less than that at the remaining portions of the drum to avoid having a zone of weak-ness at each such location with the extrusion being programmed to locate each section of additional thickness to facilitate the ~ formation of each of the projections; utilizing a longitudinally split blow molding for cooperating and forming the selected drum configuration and blow molding the parison into the selected drum configuration when the parison is disposed interiorly of the closed split blow mold, the parison being thus blown into the selected drum configuration during the blow molding cycle and such blowing being continued for a predetermined period of time to assure the formation of the selected drum configuration and the predetermined wall thickness adjacent the projections;
utilizing compressionmolds formingpart ofthe blowmold withsurfaces of thecompression moldforming thecompression moldcavity beinglongi-tudinally reciprocalin essentiallythe samedirection asthe longitu-dinal axisof theblow mold,capturing apredetermined amounto~ the additional resinin eachof theopen compressionmold cavitiesupon blow-ing ofthe parison;and compressionmolding thepredetermined additional amount ofresin intoeach ofthe projections UpOII longitudinallyrecip-rocating thecompres-. - -- 3 ll~OQ2Z
sion mold into its closed posi~ion, and at the same time assuring the predetermined wall thickness adjacent each projection, the compression molding of the projection taking place during the blow molding cycle and after the initiation of the blow molding cycle.
Desirably the tubular parison has at least two sections thereof with an additional amount of resin of increased thick-ness for the formation of at least two outwardly extending pro-jections on said drum.
In a particular aspect thereof the present invention provides a method of molding a plastic drum having at least two outwardly extending projections comprising the steps of: extruding a tubular parison of resin material having a predetermined wall thickness with at least two sections thereof having an additional amount of resin of increased thickness for formation of the pro-jections and at the same time assure a predetermined wall thick-ness of the drum adjacen~ the projections no less than that at the remaining portions of the drum to avoid having a zone of weakness at such locations with the extrusion being programmed to locate each section of additional thickness to facilitate the formation of each of the projections; utilizing a longitudinally split blow molding for cooperating and forming the selected drum configuration and blow molding the parison into the selected drum configuration when the parison is disposed interiorly of the closed split blow mold, the parison being thus blown into the selected drum configuration during the blow molding cycle and such blowing being continued for a predetermined period of time to assure the formation of the selected drum configuration and the predetermined wall thickness adjacent the projections;
utilizing at least one compression mold with surfaces of the compression mold forming the compression mold cavity being longi-tudinally reciprocal in essentially the same direction as the - 3a -longitudinal axis of the blow mold, capturing a predetermined amount of the additional resin in each of the open compression mold cavities upon blowing of the parison; and compression mold-ing the predetermined additional amount of resin into each of the projections upon longitudinally reciprocating the compression mold into its closed position, and at the same time assuring the predetermined wall thickness adjacent the projection, the compres-sion molding of the projection taking place after the initiation of the blow molding cycle.
The present invention will be further illustrated by way of the accompanying drawings in which:
Figure 1 is a side elevational view of an all plastic blow molded drum produced in accordance with the present invention;
Figure 2 is a top plan view thereof;
Figure 3 is a side elevational view of an open blow mold and compression mold shown in section with certain parts broken away and removed and with a lowered parison between the open molds;
Figure 4 shows the blow mold closed about the parison with the blow pin cooperating in introducing fluid under pressure to expand the parison into the configuration of the blow mold cavity while the compression mold is open;
Figure 5 is a similar view showing the compression mold closed after the blow molding cycle is initiated and while it continues;
`~ - 3b -l 11100;~2 Figures 3A, 4A and 5A are enlarged fragmentary sectional views of a part of the compression mold showing (i) the parison with extruded thickened sections spaced from but adjacent the open compression mold prior to blow molding (Figure 3A), (ii) the parison blown into the configuration of the closed blow mold with the thickened section forced into the cavity of the open compression mold (Figure 4A) and (iii) the compression mold closed to form the outwardly extending projection on the exterior of the blown drum during the blowing cycle (Figure 5A);
LO and Figure 6 is a longitudinal sectional view of the drum with outwardly extending projections formed in accordance with the present invention.
111~)022 DETAILED DESCRIPTION
A drum 10 molded according to the present invention in-cludes a body 12 of tubular configuration provided with an integrally formed bottom closed end 14 and an upper closed end 16. In order to facilitate the manipulation and handling of the drum, radially extending ribs 18a and 18b are formed integrally with the tubular body 12. Each rib 18a and 18b extends circumferentially around the periphery of the tubular body 14 and includes laterally extending flanges 20a and 20b, respectively. In addition, each rib defines a recess 22a and 22b, respectively, which advantageously receive and accommodates surfaces of either a chain hoo~, parrot beak hook or lifting device conventionally employed for moving drums. In addition to the undercut or reinforcing qusset, the pres~nt invention lS contemplates the formation of other forms of laterally extend-ing projections requiring compression molding as a supplement to blow molding as part of a single operation without the need of any secondary operation, especially in the field of manufacturing all plastic drums, containers or the like.
In manufacturing the drum 10, a parison 24 is initially extruded, dropped or otherwise formed. Incident to the forma-tion of the parison, predetermined sections 26 and 28 are pro-vided with additional resin forming a heavy or thickened zone in section. The programming of a parison with a heavy section is a technique well known in the blow molding industry. The parison 24 will be disposed between the open blow mold 30 then opened compression molds 36 and 38. The compression molds form part of the blow mold and extend from the cavity surfaces de-fining the tubular body 12 and bottom closed end 14 and upper closed end 16 ~see Fi~ure 3).
lllOO;~Z
The longitudinally split blow mold 30 is closed about the lowered parison 24 again in a manner well kno~n to those skilled in the art. In this connection, reference is made to commonly assigned U.S. Patent Nos. 3,212,129 and 3,266,390 for details of blow molding of plastic drums. Upon the closing of the blow mold 30, the internal blowing cycle commences to force the parison of predetermined thickness outwardly against the surfaces of the blow mold to assume the desired configuration of drum (see Figure 4).
The thickened sections 26 and 28 are blown into the expanded compression mold cavity 32 and 34, respectively, formed by the respective retracted sections of the compression molds 36 and 38. The movable compression mold section are reciprocal in a longitudinal direction in any one of many ways including the illustrated hydraulic piston-cylinder assembly 40 and 42, respectively. Immediately following the initiation of the blowing cycle, the compression molds 36 and 38 are closed about the respective thickened sections 26 and 28. The actuation of the compression molds follows a suitable time delay in order 20 to permit the expansion of the parison against the surfaces of the blow mold. In a practical application of the present in-vention, the compression molds are closed approximately five seconds after the start of the blowing cycle. The length of blowing cycle will vary depending upon the wall thickness of the drum. In connection with the practical embodiment, the blowing cycle extended over a period of approximately three minutes for a drum of approximately 55 gallons having a wall thickness of approximatel~ a minimum of 1/8" with the thic~ness increasing to about 3/8" adjacent the ribs 18a and 18b. The 30 closed compression molds 36 and 38 will advantageously form the ribs 18a and 18b, respectively.
Upon the completion of the molding cycle, the compres-lllOOX2 sion molds 36 and 38 retract to their original position.
`Thereafter, the press opens to open the split blow mold to permit the finished drum 10 to be removed.
The shape and location of the ribs 18a and 18b are determined by the configuration of the compression mold cavity and the positioning of the compression mold within the side walls of the blow mold.
As previously explained the ribs 18a and 18b may also be in the form of rolling hoops or reinforcing gussets re-quiring the use of the supplemental compression molding technique.These projections can extend completely around the circum-ferential periphery ofthe side wall of the drum or can be stratigically placed in a given area to provide a handle or hand grip. By the same token, the radial projection need not be at about 90 to the side wall of the drum, but may extend anywhere between 30 and 90 to the side wall.
It should be understood that in addition to the manu-factu~e of drums and containers the present invention is equally applicable to the formation of any other tYpe o~ hollow article.
.
111~ 2Z
Thus the several aforenoted objects and advantages are most effectively attained. Although a single somewhat pre-ferred embodiment of the invention has been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that o$ the appended claims.
_7_
The present invention relates to the moulding of plastic drums.
The present invention is particularly directed to the production of a plastic drum disclosed in copending application No. 307,777 filed on even date herewith and entitled All Plastic Blow Molded Drum.
In the above referenced copending application, an all plastic blow molded drum is disciosed and includes a tubular out-wardly bilged body having an integral upper and bottom closed end each provided with outwardly extending ribs arranged and dimen-sioned to permit stacking of one drum on top of another similar drum. The upper rib is interrupted with a sealable drain opening disposed in one of the interruptions and a vent opening disposed in the other of such interruptions. A radial circumferentially extending rib on the drum body is located near the upper end and bottom end with each rib provided with a laterally extending flange extending in the direction of the neighboring end, thereby defining a recess for accommodating surfaces of a drum moving device such as a hook or parrot beak lifting device. The radial ribs with lateral flange serve as rolling hoops and extend out-wardly in a radial direction an amount substantially the same as that of the bilge of the tubular body side wall whereby the cen-tral portions of neighboring drums can touch one another in transport without the upper and lower flanges hooking over or on each other.
~?~
The present invention provides a method of molding the foregoing all plastic drum.
The present invention also provides a method of blow molding an all plastic drum and at the same time form an outwardly extending projection thereon by a compression molding technique.
According to the present invention therefore there is provided a method of moulding a plastic drum having at least one outwardly extending projection comprising the steps of: extruding a tubular parison of resin material having a predetermined wall thickness with at least one section thereof having an additional amount of resin of increased thickness for formation of each pro-jection and at the same time assure a predetermined wall thick-ness of the drum adjacent each projection no less than that at the remaining portions of the drum to avoid having a zone of weak-ness at each such location with the extrusion being programmed to locate each section of additional thickness to facilitate the ~ formation of each of the projections; utilizing a longitudinally split blow molding for cooperating and forming the selected drum configuration and blow molding the parison into the selected drum configuration when the parison is disposed interiorly of the closed split blow mold, the parison being thus blown into the selected drum configuration during the blow molding cycle and such blowing being continued for a predetermined period of time to assure the formation of the selected drum configuration and the predetermined wall thickness adjacent the projections;
utilizing compressionmolds formingpart ofthe blowmold withsurfaces of thecompression moldforming thecompression moldcavity beinglongi-tudinally reciprocalin essentiallythe samedirection asthe longitu-dinal axisof theblow mold,capturing apredetermined amounto~ the additional resinin eachof theopen compressionmold cavitiesupon blow-ing ofthe parison;and compressionmolding thepredetermined additional amount ofresin intoeach ofthe projections UpOII longitudinallyrecip-rocating thecompres-. - -- 3 ll~OQ2Z
sion mold into its closed posi~ion, and at the same time assuring the predetermined wall thickness adjacent each projection, the compression molding of the projection taking place during the blow molding cycle and after the initiation of the blow molding cycle.
Desirably the tubular parison has at least two sections thereof with an additional amount of resin of increased thick-ness for the formation of at least two outwardly extending pro-jections on said drum.
In a particular aspect thereof the present invention provides a method of molding a plastic drum having at least two outwardly extending projections comprising the steps of: extruding a tubular parison of resin material having a predetermined wall thickness with at least two sections thereof having an additional amount of resin of increased thickness for formation of the pro-jections and at the same time assure a predetermined wall thick-ness of the drum adjacen~ the projections no less than that at the remaining portions of the drum to avoid having a zone of weakness at such locations with the extrusion being programmed to locate each section of additional thickness to facilitate the formation of each of the projections; utilizing a longitudinally split blow molding for cooperating and forming the selected drum configuration and blow molding the parison into the selected drum configuration when the parison is disposed interiorly of the closed split blow mold, the parison being thus blown into the selected drum configuration during the blow molding cycle and such blowing being continued for a predetermined period of time to assure the formation of the selected drum configuration and the predetermined wall thickness adjacent the projections;
utilizing at least one compression mold with surfaces of the compression mold forming the compression mold cavity being longi-tudinally reciprocal in essentially the same direction as the - 3a -longitudinal axis of the blow mold, capturing a predetermined amount of the additional resin in each of the open compression mold cavities upon blowing of the parison; and compression mold-ing the predetermined additional amount of resin into each of the projections upon longitudinally reciprocating the compression mold into its closed position, and at the same time assuring the predetermined wall thickness adjacent the projection, the compres-sion molding of the projection taking place after the initiation of the blow molding cycle.
The present invention will be further illustrated by way of the accompanying drawings in which:
Figure 1 is a side elevational view of an all plastic blow molded drum produced in accordance with the present invention;
Figure 2 is a top plan view thereof;
Figure 3 is a side elevational view of an open blow mold and compression mold shown in section with certain parts broken away and removed and with a lowered parison between the open molds;
Figure 4 shows the blow mold closed about the parison with the blow pin cooperating in introducing fluid under pressure to expand the parison into the configuration of the blow mold cavity while the compression mold is open;
Figure 5 is a similar view showing the compression mold closed after the blow molding cycle is initiated and while it continues;
`~ - 3b -l 11100;~2 Figures 3A, 4A and 5A are enlarged fragmentary sectional views of a part of the compression mold showing (i) the parison with extruded thickened sections spaced from but adjacent the open compression mold prior to blow molding (Figure 3A), (ii) the parison blown into the configuration of the closed blow mold with the thickened section forced into the cavity of the open compression mold (Figure 4A) and (iii) the compression mold closed to form the outwardly extending projection on the exterior of the blown drum during the blowing cycle (Figure 5A);
LO and Figure 6 is a longitudinal sectional view of the drum with outwardly extending projections formed in accordance with the present invention.
111~)022 DETAILED DESCRIPTION
A drum 10 molded according to the present invention in-cludes a body 12 of tubular configuration provided with an integrally formed bottom closed end 14 and an upper closed end 16. In order to facilitate the manipulation and handling of the drum, radially extending ribs 18a and 18b are formed integrally with the tubular body 12. Each rib 18a and 18b extends circumferentially around the periphery of the tubular body 14 and includes laterally extending flanges 20a and 20b, respectively. In addition, each rib defines a recess 22a and 22b, respectively, which advantageously receive and accommodates surfaces of either a chain hoo~, parrot beak hook or lifting device conventionally employed for moving drums. In addition to the undercut or reinforcing qusset, the pres~nt invention lS contemplates the formation of other forms of laterally extend-ing projections requiring compression molding as a supplement to blow molding as part of a single operation without the need of any secondary operation, especially in the field of manufacturing all plastic drums, containers or the like.
In manufacturing the drum 10, a parison 24 is initially extruded, dropped or otherwise formed. Incident to the forma-tion of the parison, predetermined sections 26 and 28 are pro-vided with additional resin forming a heavy or thickened zone in section. The programming of a parison with a heavy section is a technique well known in the blow molding industry. The parison 24 will be disposed between the open blow mold 30 then opened compression molds 36 and 38. The compression molds form part of the blow mold and extend from the cavity surfaces de-fining the tubular body 12 and bottom closed end 14 and upper closed end 16 ~see Fi~ure 3).
lllOO;~Z
The longitudinally split blow mold 30 is closed about the lowered parison 24 again in a manner well kno~n to those skilled in the art. In this connection, reference is made to commonly assigned U.S. Patent Nos. 3,212,129 and 3,266,390 for details of blow molding of plastic drums. Upon the closing of the blow mold 30, the internal blowing cycle commences to force the parison of predetermined thickness outwardly against the surfaces of the blow mold to assume the desired configuration of drum (see Figure 4).
The thickened sections 26 and 28 are blown into the expanded compression mold cavity 32 and 34, respectively, formed by the respective retracted sections of the compression molds 36 and 38. The movable compression mold section are reciprocal in a longitudinal direction in any one of many ways including the illustrated hydraulic piston-cylinder assembly 40 and 42, respectively. Immediately following the initiation of the blowing cycle, the compression molds 36 and 38 are closed about the respective thickened sections 26 and 28. The actuation of the compression molds follows a suitable time delay in order 20 to permit the expansion of the parison against the surfaces of the blow mold. In a practical application of the present in-vention, the compression molds are closed approximately five seconds after the start of the blowing cycle. The length of blowing cycle will vary depending upon the wall thickness of the drum. In connection with the practical embodiment, the blowing cycle extended over a period of approximately three minutes for a drum of approximately 55 gallons having a wall thickness of approximatel~ a minimum of 1/8" with the thic~ness increasing to about 3/8" adjacent the ribs 18a and 18b. The 30 closed compression molds 36 and 38 will advantageously form the ribs 18a and 18b, respectively.
Upon the completion of the molding cycle, the compres-lllOOX2 sion molds 36 and 38 retract to their original position.
`Thereafter, the press opens to open the split blow mold to permit the finished drum 10 to be removed.
The shape and location of the ribs 18a and 18b are determined by the configuration of the compression mold cavity and the positioning of the compression mold within the side walls of the blow mold.
As previously explained the ribs 18a and 18b may also be in the form of rolling hoops or reinforcing gussets re-quiring the use of the supplemental compression molding technique.These projections can extend completely around the circum-ferential periphery ofthe side wall of the drum or can be stratigically placed in a given area to provide a handle or hand grip. By the same token, the radial projection need not be at about 90 to the side wall of the drum, but may extend anywhere between 30 and 90 to the side wall.
It should be understood that in addition to the manu-factu~e of drums and containers the present invention is equally applicable to the formation of any other tYpe o~ hollow article.
.
111~ 2Z
Thus the several aforenoted objects and advantages are most effectively attained. Although a single somewhat pre-ferred embodiment of the invention has been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that o$ the appended claims.
_7_
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of moulding a plastic drum having at least one outwardly extending projection comprising the steps of:
extruding a tubular parison of resin material having a predeter-mined wall thickness with at least one section thereof having an additional amount of resin of increased thickness for formation of each projection and at the same time assure a predetermined wall thickness of the drum adjacent each projection no less than that at the remaining portions of the drum to avoid having a zone of weakness at each such location with the extrusion being pro-grammed to locate each section of additional thickness to facili-tate the formation of each of the projections; utilizing a longi-tudinally split blow molding for cooperating and forming the selected drum configuration and blow molding the parison into the selected drum configuration when the parison is disposed interiorly of the closed split blow mold, the parison being thus blown into the selected drum configuration during the blow molding cycle and such blowing being continued for a predetermined period of time to assure the formation of the selected drum configuration and the predetermined wall thickness adjacent the projections; utiliz-ing compression molds forming part of the blow mold with surfaces of the compression mold forming the compression mold cavity being longitudinally reciprocal in essentially the same direction as the longitudinal axis of the blow mold, capturing a predetermined amount of the additional resin in each of the open compression mold cavities upon blowing of the parison; and compression molding the predetermined additional amount of resin into each of the pro-jections upon longitudinally reciprocating the compression mold into its closed position, and at the same time assuring the pre-determined wall thickness adjacent each projection, the compres-sion molding of the projection taking place during the blow mold-ing cycle and after the initiation of the blow molding cycle.
extruding a tubular parison of resin material having a predeter-mined wall thickness with at least one section thereof having an additional amount of resin of increased thickness for formation of each projection and at the same time assure a predetermined wall thickness of the drum adjacent each projection no less than that at the remaining portions of the drum to avoid having a zone of weakness at each such location with the extrusion being pro-grammed to locate each section of additional thickness to facili-tate the formation of each of the projections; utilizing a longi-tudinally split blow molding for cooperating and forming the selected drum configuration and blow molding the parison into the selected drum configuration when the parison is disposed interiorly of the closed split blow mold, the parison being thus blown into the selected drum configuration during the blow molding cycle and such blowing being continued for a predetermined period of time to assure the formation of the selected drum configuration and the predetermined wall thickness adjacent the projections; utiliz-ing compression molds forming part of the blow mold with surfaces of the compression mold forming the compression mold cavity being longitudinally reciprocal in essentially the same direction as the longitudinal axis of the blow mold, capturing a predetermined amount of the additional resin in each of the open compression mold cavities upon blowing of the parison; and compression molding the predetermined additional amount of resin into each of the pro-jections upon longitudinally reciprocating the compression mold into its closed position, and at the same time assuring the pre-determined wall thickness adjacent each projection, the compres-sion molding of the projection taking place during the blow mold-ing cycle and after the initiation of the blow molding cycle.
2. A method in accordance with claim 1, wherein the additional amount of resin is in the form of a circumferentially extending thickened section.
3. A method in accordance with claim 2, wherein the circumferentially extending thickened section is formed into an undercut outwardly projecting rib having a recess which receives and accommodates surfaces of a lifting device for facilitating moving of the drum.
4. A method as claimed in claim 1, 2 or 3 in which the extruded tubular parison has at least two sections thereof with an additional amount of resin of increased thickness for the for-mation of at least two outwardly extending projections on said drum.
5. A method in accordance with claim 1, 2 or 3 wherein at least two of such ribs are compression molded on the exterior of the drum with one rib being near the top of the drum and the other rib being near the bottom of the drum and each rib recess being open in the direction of the adjacent end of the drum.
6. A method of molding a plastic drum having at least two outwardly extending projections comprising the steps of:
extruding a tubular parison of resin material having a predeter-mined wall thickness with at least two sections thereof having an additional amount of resin of increased thickness for formation of the projections and at the same time assure a predetermined wall thickness of the drum adjacent the projections no less than that at the remaining portions of the drum to avoid having a zone of weakness at such locations with the extrusion being programmed to locate each section of additional thickness to facilitate the formation of each of the projections; utilizing a longitudinally split blow molding for cooperating and forming the selected drum configuration and blow molding the parison into the selected drum con-figuration when the parison is disposed interiorly of the closed split blow mold, the parison being thus blown into the selected drum configuration during the blow molding cycle and such blowing being continued for a predetermined period of time to assure the formation of the selected drum configuration and the predetermined wall thickness adjacent the projections;
utilizing at least one compression mold with surfaces of the compression mold forming the compression mold cavity being longi-tudinally reciprocal in essentially the same direction as the longitudinal axis of the blow mold, capturing a predetermined amount of the additional resin in each of the open compression mold cavities upon blowing of the parison; and compression mold-ing the predetermined additional amount of resin into each of the projections upon longitudinally reciprocating the compression mold into its closed position, and at the same time assuring the predetermined wall thickness adjacent the projection, the compres-sion molding of the projection taking place after the initiation of the blow molding cycle.
extruding a tubular parison of resin material having a predeter-mined wall thickness with at least two sections thereof having an additional amount of resin of increased thickness for formation of the projections and at the same time assure a predetermined wall thickness of the drum adjacent the projections no less than that at the remaining portions of the drum to avoid having a zone of weakness at such locations with the extrusion being programmed to locate each section of additional thickness to facilitate the formation of each of the projections; utilizing a longitudinally split blow molding for cooperating and forming the selected drum configuration and blow molding the parison into the selected drum con-figuration when the parison is disposed interiorly of the closed split blow mold, the parison being thus blown into the selected drum configuration during the blow molding cycle and such blowing being continued for a predetermined period of time to assure the formation of the selected drum configuration and the predetermined wall thickness adjacent the projections;
utilizing at least one compression mold with surfaces of the compression mold forming the compression mold cavity being longi-tudinally reciprocal in essentially the same direction as the longitudinal axis of the blow mold, capturing a predetermined amount of the additional resin in each of the open compression mold cavities upon blowing of the parison; and compression mold-ing the predetermined additional amount of resin into each of the projections upon longitudinally reciprocating the compression mold into its closed position, and at the same time assuring the predetermined wall thickness adjacent the projection, the compres-sion molding of the projection taking place after the initiation of the blow molding cycle.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US920,061 | 1978-06-28 | ||
| US05/920,061 US4170623A (en) | 1978-03-20 | 1978-06-28 | Method of blow molding an all plastic drum and compression molding a projection thereon |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1110022A true CA1110022A (en) | 1981-10-06 |
Family
ID=25443089
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA307,776A Expired CA1110022A (en) | 1978-06-28 | 1978-07-20 | Method of blow molding an all plastic drum and compression molding a projection theron |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS555887A (en) |
| CA (1) | CA1110022A (en) |
| DE (1) | DE2843542A1 (en) |
| FR (1) | FR2429659A1 (en) |
| GB (1) | GB2026373B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3226872A1 (en) * | 1982-07-17 | 1984-01-19 | Mauser-Werke GmbH, 5040 Brühl | METHOD FOR PRODUCING A HOLLOW BODY |
| JPH0642618B2 (en) * | 1984-02-28 | 1994-06-01 | 日本無線株式会社 | Surface acoustic wave filter |
| FR2771961B1 (en) * | 1997-12-10 | 2000-01-14 | Moulage Tech Soufflage Mts | MOLD FOR USE IN MOLDING PARTS BY A BLOWING TECHNIQUE |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| LU37148A1 (en) * | 1958-07-26 | |||
| US3159697A (en) * | 1962-07-17 | 1964-12-01 | Tucker Mfg Corp | Blow and compression molding eccentrically thick parison |
| NL300474A (en) * | 1962-11-13 | 1900-01-01 | ||
| DE1454915A1 (en) * | 1963-09-20 | 1969-05-14 | Agk Ag Fuer Kunststoffprodukte | Method and tool for the production of plastic knives |
| DE2426736C3 (en) * | 1974-06-01 | 1981-05-07 | Ossberger-Turbinenfabrik, 8832 Weissenburg | Device for producing a preform for blow molding a hollow body |
| DE2522094C3 (en) * | 1975-05-17 | 1981-08-06 | Maschinen- Und Werkzeugbau Gmbh, 3563 Dautphetal | Plastic containers and blow molded for its manufacture |
| DE2544491C2 (en) * | 1975-10-04 | 1983-12-22 | Mauser KG, 5040 Brühl | Lidded barrel |
| DE2600829A1 (en) * | 1976-01-12 | 1977-08-04 | Mauser Kg | Blown thermoplastic barrel with hoops - with recesses in mould dividing planes for receiving hoop material |
-
1978
- 1978-07-20 CA CA307,776A patent/CA1110022A/en not_active Expired
- 1978-08-07 GB GB7832423A patent/GB2026373B/en not_active Expired
- 1978-08-17 JP JP10044778A patent/JPS555887A/en active Granted
- 1978-10-05 DE DE19782843542 patent/DE2843542A1/en not_active Ceased
- 1978-10-11 FR FR7829055A patent/FR2429659A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB2026373A (en) | 1980-02-06 |
| GB2026373B (en) | 1982-11-03 |
| FR2429659B1 (en) | 1984-03-16 |
| JPS555887A (en) | 1980-01-17 |
| FR2429659A1 (en) | 1980-01-25 |
| JPS5761583B2 (en) | 1982-12-24 |
| DE2843542A1 (en) | 1980-01-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |