GB2042462A

GB2042462A - A barrel

Info

Publication number: GB2042462A
Application number: GB7941035A
Authority: GB
Original assignee: Mauser KG
Current assignee: Mauser KG
Priority date: 1978-12-07
Filing date: 1979-11-28
Publication date: 1980-09-24
Also published as: DE2852922A1; IT7927972A0; DK212379A; BE876816A; ATA438879A; SE7904815L; NL7904030A; JPS55116548A; BR7905344A; CA1120413A; IT1126549B; AT366638B; SU934904A3; NO791840L; FR2443388A1; GB2042462B; JPS5733215B2

Abstract

A blow-moulded barrel of thermoplastic synthetic resin has diametrically- opposed longitudinal mould dividing seams in the barrel side wall, and comprises a barrel body (3) and integral L-section handling chimes (1, 2) adjacent the top and bottom thereof so as to define upwardly and downwardly directed annular channels (9) respectively. The height of the chimes (1, 2) and the wall thickness of the radial flanges (13) are constant over the whole circumference of the barrel. However, in order to ensure complete formation of the chimes during blow moulding, the wall thickness of each axial flange (10) decreases continuously from the region of one seam through 90 DEG in both circumferential directions to opposed intermediate regions, where the wall thickness of each axial flange is substantially equal to the wall thickness of the barrel body, and then increases therefrom to the region of the other seam. <IMAGE>

Description

SPECIFICATION A barrel The present invention relates to a blowmoulded barrel of a thermo-plastic synthetic resin.

In our patent application No. 30293/77, such a barrel was disclosed comprising a barrel body having upper and lower chimes formed integrally therewith. Each chime has a substantially "L"-shaped cross-section and comprises a radial flange and a peripheral axial flange, the axial flange at the top and bottom of the barrel'extending away from the respective radial flange towards the top and bottom of the barrel respectively so as to define upwardly and downwardly directed annular channels respectively, whereby the barrel may be gripped and carried by a gripping and carrying tool.

This configuration of the chimes has a special significance. Lower and upper tong arms of a gripping tool engage under the radial flange, and behind the axial flange, respectively. The total load of the barrel is transferred to the lower tong arm, whereas the upper tong arm engaging behind the axial flange prevents the barrel from sliding off. For this reason the axial flange of the upper chime must be directed upwards, and the axial flange of the lower chime must be directed downwards.

The known mould for producing such a barrel comprises two mould halves with a longitudinally extending dividing plane. The two mould halves are divided once more horizontally in their upper and lower region, so that sliders are produced.

Before a tube of extruded material is lowered from a tube head of an extrusion machine, the two mould halves are displaced apart to the left and to the right, so that the tube can enter into the open mould. The top and bottom sliders are open. After the tube has been lowered longitudinally through the mould, the two mould halves are closed and blow moulding begins. The air flowing in through blowing mandrels expands the tube against the internal wall of the closed mould so that the tube takes the predetermined shape of the barrel. The upper siiders and the lower sliders are open, so that the tube material can enter into open upper and lower annular mould pockets, so as to form peripheral annular recesses open to the inside of the barrel.

The sliders are then closed by axial movement towards each other. In the mould dividing surfaces profiles are provided which correspond to the shape of the chimes and into which the material displaced from the barrel wall enters. The upper and lower chimes moulded in this manner each have a substantially L-shaped cross-section and comprise a radial (horizontal) flange, and a peripheral axial (vertical) flange directed upwards and downwards, respectively.

Difficulties arise in the moulding of such chimes owing to the different distribution of material in the barrel wall. When the twomould halves are first closed, the tube wall at the top and bottom of the extruded tube is squeezed together to form upper and lower flattened seams of double wall thickness extending across the mould between the diametrically-opposed longitudinal mould dividing seams. During blow moulding the tube is dilated, and the thickness of the tube is reduced the greater the radial distance from the flattened seam.

Thus different amounts of material are available around the periphery of the mould for the formation of the chimes and consequently the sliders cannot close fully in the region of the seam because of the greater quantity of material there. As a result, the thickness of the chimes remote from these seams is reduced, because the sliders are not completely closed. In order to be able to use gripping tools reliably, the chimes must be completely formed.

According to our UK Patent Application No.

20838/78 a mould is used to provide a radial flange in which the wall thickness decreases continuously from the region of one seam through 90 in both circumferential directions to opposed intermediate regions, where the wall thickness of the radial flange is substantially equal to the wall thickness of the barrel body, and then increases therefrom to the region of the other seam. The thickness of the axial flanges and the height of the annular channels remains constant around the whole periphery of the barrel, since the sliders can now close fully.

An object of the invention is to provide an alternative barrel having chimes of L-shaped cross-section moulded integrally with the barrel wall and having a uniform engagement channel while taking into account the irregular distribution of material during moulding.

The invention provides a blow-moulded barrel of thermoplastic synthetic resin having diametrically-opposed longitudinal mould dividing seams in the barrel side wall, and comprising a barrel body and chimes adjacent the top and bottom thereof, the chimes being formed integrally with the barrel body, each chime having a substantially L-shaped crosssection and comprising a radial flange and a peripheral axial flange, the axial flange at the top and bottom of the barrel extending away from the respective radial flange towards the top and bottom of the barrel respectively so as to define upwardly and downwardly directed annular channels respectively, whereby the barrel may be gripped and carried by a gripping and carrying tool, wherein the height of the chimes and the wall thickness of the radial flanges are constant over the whole circumference of the barrel, whereas the wall thickness of each axial flange decreases continuously from the region of one seam through 90 in both circumferential directions to opposed intermediate regions, where the wall thickness of each axial flange is substantially equal to the wall thickness of the barrel body, and then increases therefrom to the region of the other seam.

The invention further provides a mould for blow moulding such a barrel.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, wherein: Figure 1 is a side, part-sectional view of a barrel with upper and lower chimes, and Figure 2 is a plan view of the barrel of Fig.

1.

In Fig. 1 a barrel comprises a barrel body 3 having a top 4 and a bottom 5, the top 4 having bung holes 6 and 7. Upper and lower chimes 1 and 2 are moulded integrally with the barrel body 3 after blow moulding by axially moving mould parts (sliders-not shown) together. The chimes 1 and 2 each comprise a radial (horiyontally-extending) annular flange 1 3 and a peripheral, axial (vertically-extending) annular flange 10 directed towards the barrel top 4 and the barrel bottom 5, respectively.

The barrel top 4 and the barrel bottom 5 project beyond the chimes 1 and 2, so that the chimes are protected when a plurality of barrels are stacked one on top of the other, but that sufficient place remains that handling of the barrel is not hindered. The bung holes 6 and 7 are accommodated in depressions 8 of the barrel head 4.

The barrel side wall has diametrically-opposed longitudinal mould dividing seams (not shown) and these lie in the vertical plane through the centres of the bung holes 6 and 7. During moulding of the chimes, the largest accumulation of material occurs in the region of these seams. The mould is so shaped so that when fully closed the wall thickness of the axial flanges 10, starting from the region of one mould dividing seam, decreases steadily through 90 in both circumferential directions to opposed intermediate regions, where the wall thickness of each axial flange 10 is substantially equal to the wall thickness of the barrel body 3. The wall thickness of the axial flanges 10 then increases from there steadily to the region of the other mould dividing seam. The depth of channels 9 formed between the chimes and the barrel body is constant over the whole circumference of the barrel.

As may be seen further from Fig. 2, the radial flange 1 3 has an enlarged width 11 in the region of the largest accumulation of material adjacent the bung holes 6 and 7 (i.e.

adjacent the mould dividing seams) by radially-inwards deformation of the barrel body adjacent the bung holes 6 and 7.

Claims

1. A blow-moulded barrel of thermoplastic synthetic resin having diametrically-opposed longitudinal mould dividing seams in the barrel side wall, and comprising a barrel body and chimes adjacent the top and bottom thereof, the chimes being formed integrally with the barrel body, each chime having a substantially L-shaped cross-section and comprising a radial flange and a peripheral axial flange, the axial flange at the top and bottom of the barrel extending away from the respective radial flange towards the top and bottom of the barrel respectively so as to define upwardly and downwardly directed annular channels respectively, whereby the barrel may be gripped and carried by a gripping and carrying tool, wherein the height of the chimes and the wall thickness of the radial flanges are constant over the whole circumference of the barrel, whereas the wall thickness of each axial flange decreases continuously from the region of one seam through 90 in both circumferential directions to opposed intermediate regions, where the wall thickness of each axial flange is substantially equal to the wall thickness of the barrel body, and then increases therefrom to the region of the other seam.

2. A blow-moulded barrel as claimed in claim 1, wherein the width of the radial flange of the chime adjacent the barrel top is formed greater adjacent the seams by inward deformation of the barrel body adjacent the seams.

3. A blow-moulded barrel substantially as herein described with reference to the accompanying drawings.

4. A mould for blow-moulding a barrel of thermoplastic synthetic material as claimed in any one of the preceding claims comprising two mould halves for forming the barrel body and having a longitudinally-extending dividing plane forming diametrically-opposed longitudinal mould dividing seams in the barrel side wall, upper and lower axially-movable slider members shaped to form the barrel top and bottom and to define with the mould halves annular peripheral recesses for forming an upper and lower chime integrally with the barrel body, so that each chime has a substantially L-shaped cross-section and comprises a radial flange and a peripheral axial flange, the axial flange at the top and bottom of the barrel extending away from the respective radial flange towards the top and bottom of the barrel respectively so as to define upwardly and downwardly directed annular channels respectively, whereby the barrel may be gripped and carried by a gripping and carrying tool, wherein in the fully closed position of the mould the annular recesses are shaped to form chimes having a constant height and with radial flanges of constant thickness around the periphery of the barrel, and to form each axial flange with a wall thickness decreasing continuously from the region of one seam through 90 in both circumferential directions to opposed intermediate regions, where the wall thickness of each axial flange is substantially equal to the wall thickness of the barrel body, and then increasing therefrom to the region of the other seam.