Closure for a canister

A closure for a plastic canister in the 20-30 liter range has a collar coaxial with a pouring spout on the canister, with side abutments with lower surfaces arranged to cooperate with the claws of the closure. A cap is arranged to swing between an open condition and a closed condition relative to the collar. The claw is approximately U-shaped, with a transverse gripping web and two longitudinal webs ending in a fork having an upper and a lower prong. The upper prongs are arranged to form a swivel hinge with journals on the cap. The lower prongs have inner surfaces arranged to cooperate with lower surfaces of the abutments such that when the gripping web is pressed downward a sealing ring in the cap is pressed onto the end face of the pouring nozzle. The collar is arranged to fit against the cap with minimal spacings and the claw is arranged to fit against the collar and the cap with minimal spacings, when the cap is in the closed condition. The spacings permit relative movement of the claw and the cap during opening and closing of the cap, and are smaller than deformations occurring as a result of impact loads on the closure.

This invention relates to a claw-type closure for a plastic canister in the 
20-30 liter range. 
BACKGROUND OF THE INVENTION 
A closure of this kind was disclosed, for example, in German patent 
specification No. 3,031,945. This closure from the same inventor has the 
following disadvantages: 
(a) The canisters do not stack well because the second canister stacked on 
a particular canister is poorly supported in the region of the closure. 
(b) The closure is made up of a large number of different parts. 
(c) It is difficult to open if an attendant is wearing gloves. 
(d) In practice, a safety catch prestressed by a leaf spring is necessary 
to ensure that the closure does not come open under adverse conditions. It 
is thus necessary, first of all, to undo the catch and then open the claw. 
If, however, in disaster situations, several hundred canisters have to be 
opened quickly, this means an extremely great loss of time and 
furthermore, that an attendant will be able to open perhaps 30 canisters 
but will then be lacking the strength to open further canisters. 
(e) The force required to open and close the claw is great, even 
disregarding the leaf spring catch. 
(f) In a drop test, a full canister is thrown closure-first from a height 
of several meters onto a concrete slab, both when the temperature is 
extremely low and when it is extremely high. In the case of the known 
closure, it is difficult to fulfill these conditions. 
(g) Although the overall design of the closure makes it possible to cast 
the collar in metal, it is not possible in the case of this design to 
produce the claw and the cap by casting as well, whether in plastic or 
optionally metal and/or plastic. 
OBJECT AND STATEMENT OF THE INVENTION 
It is the object of the invention to provide a closure which overall avoids 
the disadvantages indicated above but nevertheless leads to a closure 
which is simple, can accordingly be cheap and which anyone can understand 
how to operate even if seeing it for the first time and which, in terms of 
force, can be frequently and successfully operated by even weak or 
weakened persons. 
This object is achieved by a claw-type closure having the following 
features: 
a collar coaxial with a pouring spout on the canister, having a rearward 
periphery and sides having two abutments, the abutments having lower 
surfaces arranged to cooperate with the claws of the closure, 
a cap with a sealing ring therein and lateral and rearward edge regions, 
the cap being arranged to swing between an open condition and a closed 
condition relative to the collar, 
a first hinge half projecting from the rearward periphery of the collar, 
a second hinge half on the rearward edge region of the cap that cooperates 
with the first hinge half, 
the first and second hinge halves being shaped to prevent the cap from 
swinging to the closed condition when the cap is in the open condition, 
two journals arranged on the lateral edge regions of the cap, and 
a claw that is approximately U-shaped, seen in plan view, with a transverse 
gripping web with end regions, and two longitudinal webs emanating from 
the end regions, 
each of the longitudinal webs ending at a free end in a fork having an 
upper and a lower prong as seen in the closed condition of the cap, 
each of the upper prongs being arranged to form a swivel hinge with the 
journals, 
each of the lower prongs having an inner surface arranged to cooperate with 
the lower surfaces of the abutments such that when the gripping web is 
pressed downward the sealing ring in the cap is pressed onto the end face 
of the pouring nozzle, 
the collar being arranged to fit against the cap with minimal spacings and 
the claw being arranged to fit against the collar and the cap with minimal 
spacings, when the cap is in the closed condition, the spacings permitting 
relative movement of the claw and the cap during opening and closing of 
the cap, the spacings being smaller than deformations occurring as a 
result of impact loads on the closure. 
Advantageously, the invention includes the following additional features: 
The length and breadth of the closure in the closed condition are greater 
than 10 cm. By virtue of these dimensional minimums, it is possible to 
arrive at dimensions which are favorable for absorbing impact forces, are 
favorable for absorbing the forces encountered during stacking, and which 
avoid the problems which arise when dealing with small components. The 
parts can be of such broad dimensions that the material flows 
satisfactorily into the cavities provided for them in the injection molds. 
The breadth is between 10 and 14 cm., and preferably in the region of 13 
cm. This effect can be increased still further by virtue of these 
dimensions, while the size of the closure nevertheless remains within the 
scope of 20 to 30 liter canisters. 
The length is between 12 and 16 cm., and preferably in the range of 14-15 
cm. The same applies in corresponding fashion to these dimensions. 
Plastic is the material of which at least one of the following is composed: 
the collar, the cap and the claw. The plastic is glass fiber-reinforced 
plastic. It is thus possible to achieve a simple and inexpensive mode of 
manufacture, which is nevertheless of high strength and has a long life. 
If highly flammable liquids are transported in the canisters, the 
possibility of spark generation and hence the risk of an explosion is 
reduced. This risk is absent when all the parts are made of plastic. 
The plastic is glass fiber-reinforce polycarbonate type. The plastic is of 
the Zytel type (registered trademark of the DuPont Company). The plastic 
is of the Rynite type (registered trademark of the DuPont Company). Such 
plastics have proven highly suitable in tests. 
The collar comprises a lower, annular, solid body that firmly surrounds the 
pouring nozzle, having a coaxial inner rim with an outside diameter that 
is substantially smaller than the outside diameter of the collar, the 
inner rim projecting upwards from the body, and a coaxial supporting ledge 
forming an end face of the body outside the inner rim, and the cap has an 
inside diameter that is slightly greater than the outside diameter of the 
inner rim of the body. These features enable the body to absorb well the 
radial opposing forces of the pouring nozzle, enable the closure to be of 
low constructional height and enable the collar to fit well against the 
cap. 
The inner rim and the outer rim are at least approximately equal in height. 
By virtue of this feature the height of the closure is furthermore 
minimized and the surface area is increased to an optimum enabling the 
shear forces between the collar and the cap to be absorbed. 
The cap has an upper surface and the outer rim continues as a bead for 
several millimeters above the upper surface. By virtue of this feature the 
cap is reinforced without making an over-large depression, and furthermore 
the probability that forces will act on the bead is then higher, and this 
bead can then divert these forces into the body by the shortest route. 
The canister has handles with upper sides defining a stacking plane of the 
canister, and the bead does not extend above the stacking plane. By virtue 
of these features, the bead is prevented from making the stacking surface 
on the upper side of the cap uneven. 
In the region of the hinge halves, the cap and the collar are approximately 
as broad as the outer diameter of the pouring nozzle. By virtue of this 
feature, a closure which is broad in the rearward region is achieved, this 
having the advantage that the forces acting on the hinge halves are widely 
spaced, so that these forces can be absorbed efficiently. In addition, it 
is then possible to make the stacking surface large. 
The hinge halves comprise two solid gudgeons between which a solid hinge 
block is located. By virtue of this feature, hinge halves are obtained 
which absorb the forces efficiently and this virtually without rattling in 
the lateral direction. 
The hinge block is provided on the collar. By virtue of this feature, the 
hinge block, as part of the body, reinforces the collar at this point. 
The hinge block is traversed by a circular, cylindrical pin, the ends of 
which form a swivel axis for the gudgeons. The pin is a metal pin. By 
virtue of these features, it is possible to injection-mold the hinge block 
in a simple manner. The metal pin extends over a relatively long length 
and is thus able to direct its forces efficiently into the hinge block and 
the metal pin can furthermore absorb large forces in its critical end 
region. 
The collar has a widened region with complimentary recesses for the 
gudgeons. This feature enables the two hinge halves to fit together very 
closely, this entailing the abovementioned advantages. 
In side elevation and in the closed condition, the gudgeons have at least 
substantially the same profile as the hinge block. By virtue of this 
feature, a closure is obtained which, in the closed condition, has similar 
effects to those of a one-piece component. 
The cap has a face on the rearward edge region, the hinge block has a rear 
upper region, each of the gudgeons has an approximately heart-shaped 
recess with a tip that points upwards, a lower heart chamber, and an upper 
heart chamber, a pin is arranged to lie in the lower heart chamber in the 
closed condition and in the upper heart chamber in the open condition, and 
in the open condition the face on the rearward edge region rests against 
the rear upper region of the hinge block. By virtue of these features, the 
cap is prevented in a simple manner from swinging forward during pouring, 
even when, for example, the central handle of the canister is absent or is 
too remote from the hinge region. 
The claw and the cap have rear upper sides, and the canister has a stacking 
plane along the rear upper sides of the claw and the cap. By virtue of 
these features, large stacking surfaces are obtained, making the cap 
almost more suitable for absorbing stacking forces than the canister 
handles. 
In the closed condition the gripping web of the claw rests on at least one 
of the hinge halves. By virtue of these features, an autonomous system is 
obtained, the parts of which fit into one another well and can absorb 
forces efficiently. 
The canister has a central handle and two outer handles, and the gripping 
web extends a long way beyond the sides of the central handle towards the 
outer handles. By virtue of these features, the gripping web can be 
gripped well even with gloves and, furthermore, large bearing surfaces and 
favorable force conditions are obtained. 
The abutments are integral with the collar and comprise prestressed 
downward-arched portions. By virtue of this feature, a closure of low 
constructional height is achieved, and the abutment in the form of a 
U-shaped bow which was hitherto used and presented difficulties in terms 
of production technolody is avoided. 
The collar has a supporting ledge, each abutment has an upper side that 
lies approximately at the level of the supporting ledge and a lower region 
on the downward arched portion that lies approximately halfway up the 
collar body, and the lower prong has a region of engagement with the 
downward arched portion that is approximately equal in height to the lower 
half of the collar body. By virtue of these features, the abutment comes 
to be located relatively far up, which means that the lower prong can be 
relatively high, enabling the abutment and the lower prong in the optimum 
case to absorb forces of approximately the same magnitude. 
Each lower prong has an outer surface, and each abutment has an outside 
with a downward-pointing guide rib for the outer surface of the lower 
prong. By virtue of these features, the lower prong is provided with 
guidance in the closed condition in the event of overloading. 
Each abutment has an arched portion, and each lower prong has an upper side 
with a transverse groove into which the arched portion of the abutment 
locks when the claw is closed. The arched portion locks deeply. By virtue 
of these features, the closure is secured against unintentional opening. 
In addition, the claw in this case moves automatically into the closing 
position at the end of the closing movement, and finally locking is then 
clearly heard, the canister itself acting as a sound-amplifying drum. This 
acoustic check is important, in particular when a large number of 
canisters have to be closed when tired. 
The transverse groove is spaced below and a short distance from the 
journal. The distance is ultra-short. By virtue of these features, the 
region between the upper prong and the lower prong, the region being 
subjected to bending stress and other forces, is reduced to a minimum and 
can thus absorb the forces efficiently. 
In the closed condition the lower prong does not protrude beyond the 
journal. By virtue of this feature, a compact functional block is obtained 
in this region, with the result that, for example, forces acting from 
above cannot force the lower prong in the opening direction. In addition, 
a flat, self-contained unit is in this case obtained at this point, so 
that the parts located at this point absorb forces to an equal extent. 
Each lower prong has a front end, each abutmment has a front edge, and each 
upper prong has a front end, all of which lie approximately in one plane. 
These features reinforce the above effect further. 
Each upper prong has an underside, and each abutment has an upper side that 
are spaced a short distance from one another. By virtue of these features, 
the constructional height is further minimized. 
Injection molding is used for at least one of the following: the collar, 
the cap, and the claw. By virtue of these features, simple, cheap and 
nevertheless dimensionally accurate production is achieved. In addition, 
injection-molded parts are at least in the majority of cases, tougher and 
can be used to produce larger-area shapes than is possible, for example, 
by plate bending.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Without intending to limit the scope of the claims to the embodiment 
described, a canister 12 is blow-molded from plastic and has the usual 
overall dimensions of 20 liter canisters. Its central handle 13 is formed 
during the blowing operation. The outer handles 14, 16 are inserted into 
the blow-molded halves as components according to the state of the art, 
which are injection-molded and are accordingly capable of withstanding 
greater loads. To the left of the left-hand declivity 17 of the handles, 
the upper side of the canister 12 merges into an oblique surface 18 which 
slopes at about 30 degrees, and from which there emanates a pouring nozzle 
19 which, according to FIG. 1 points upwards to the left. On its outside, 
this bears a coarse thread 21 which was produced during the blowing 
operation. An O-ring 22 is provided in the transitional zone between the 
pouring nozzle 19 and the oblique surface 18. 
An insert 23, which has an internal thread 24, has a vent 26 at the top, 
which continues through to the inside in a manner not shown, and on the 
inside has a breather tube 27 seated inside the pouring nozzle 19. A 
closure 28 comprises a collar 29, a cap 31 and a claw 32. All three are 
injection-molded from glass fiber-reinforced plastic. Over large areas, 
the collar 29 is coaxial to the geometric longitudinal axis 33. Its body 
34 has an outside radius of 53 mm in the region lying to the left of the 
geometrical longitudinal axis 33 in FIG. 4. The outer surface 36 is 
coaxial in circular cylindrical manner to the longitudinal axis 33 and, 
shortly before the abutments 37, 38, changes into a flattened portion 39, 
41 which likewise extends over the full height of the body 34. Towards the 
rear the flattened portions 39, 41 are adjoined by tapering surfaces 42, 
43 which extend parallel to the longitudinal axis 33 and in each case 
taper towards the rear at an angle of 10.degree. as shown in FIGS. 6 and 
8. To the inside of the tapering surfaces 42, 43 the wall of the body 34 
accordingly becomes thicker. At the rear end of the tapering surfaces 42, 
43 these recede inwards by in each case 15 mm parallel to a central plane 
44 running through the longitudinal axis 33, giving rise to rear surfaces 
46, 47. Centrally between the latter, a hinge block 48 projects backwards 
for about 25 mm, a part capable of withstanding high loads being the 
result. On each side, the hinge block 48 is delimited by end surfaces 49, 
51 which extend perpendicular to the central plane 44. Its underside 52 
extends perpendicular to the central axis 33 and is flush with the lower 
annular surface 53 of the body 34 both where the latter conforms to the 
circular shape and in the region to the inside of the tapering surfaces 
42, 43. Towards the rear, the underside merges by a radiused portion 54 of 
9 mm into a short rear surface 56 which extends parallel to the central 
plane 44 and rises to a height of 18 mm as seen from the underside 52. 
There then follows a radiused portion 57 of 12 mm and a distinct edge 58 
is thus formed (FIG. 10) against which--as shown below--a region of the 
cap 31 can rest to prevent it from swinging forwards during pouring. An 
upperside 59 extends perpendicular to the central plane 44 at a distance 
of 22 mm from the underside 52. A circular cylindrical through bore 61, 
the center of which is the center of the radius portion 54, runs through 
the hinge block 48 perpendicularly to the plane of projection of FIG. 10. 
The position of the center is evident from FIG. 10. A metal pin 62 (not 
shown in FIG. 10) which is of one piece and the ending of which is 
determined by the alignment of the tapering surfaces 42, 43 is held in 
axially nondisplaceable manner in the through bore. According to FIG. 10, 
the distance between the center of the through bore 61 and the 
longitudinal axis 33 is 60 mm. As drawn in FIG. 10, the annular surface 53 
is narrow and continues inwards with a 2 mm-high coaxial annular surface 
63. A conical surface 64 lying at 45.degree. extends upwards from the 
latter. This conical surface in turn merges into a trapezoidal thread 66 
which is coaxial, of the Tr 88 type and has a pitch of 6.35. The 
trapezoidal thread 66 also continues on the inside in a coaxial inner rim 
67, which has an outer surface 70 which runs rounf in a completely 
circular-cylindrical manner and lies on a diameter of 93 mm. A supporting 
ledge 68 which extends perpendicular to the geometric longitudinal axis 33 
and is about 5 mm wide is thereby produced on the upper side of the body 
34. At the rear, there is a completely flush transition between the 
supporting ledge 68 and the upper side 59. To the inside of the tapering 
surfaces 42, 43, the supporting ledge 68 widens, as shown in FIG. 10a. The 
same applies for the upper side 59, where it is likewise flat, of large 
surface area and always perpendicular to the longitudinal axis 33. At the 
top and on the outside, the coaxial inner rim 67 has a bezel 69. One 
abutment 71, 72, which is symmetrical in shape with respect to the central 
plane 44 in each case projects outwards in the region of the flattened 
portion 39, 41 just below the supporting ledge 68. Each abutment 71, 72 is 
essentially as wide as the associated flattened portion 39, 41 and has a 
flat upper side 73 which runs perpendicular to the longitudinal axis 33. 
Since both abutments are in mirror-image symmetry, only abutment 71 is 
described. It has an upper side 73 which extends perpendicular to the 
central plane 44 and begins just below the supporting ledge 68. It 
projects about 15 mm outwards and is about 19 mm wide. Abutment 71 is 
approximately triangular in shape, the tip of the triangle pointing 
downwards and all angles being rounded. The lower rounded tip 74 is 
situated approximately half way between the supporting ledge 68 and the 
annular surface 53 the rounded tip 74 extends outwards for about 11 mm 
from the flattened portion 41. The triangular shape of the abutment 71 
produces a rear stop surface 76 and a front stop surface 77, both of which 
are symmetrical with respect to the central plane 44. The rounded tip 74 
has a radiused portion of 4 mm. A guide rib 78 which points downwards in 
the manner of a triangle, is a mere 2 mm thick and, according to FIG. 11, 
projects, in accordance with its profile, beyond the stop surface 76, 77 
and the rounded tip 74, is provided at the outside of the abutment 71. At 
the bottom, the guide rib 68 has a relatively large rounded portion 79 of 
about 6 mm. 
A cap 31 has a cap base 81 which, when the cap is closed, is coaxial to the 
longitudinal axis 33. Its dimensions can be taken from the 1:1 
representation in FIG. 9. A thin rim 82, the outside diameter of which is 
substantially smaller than the inside diameter of the insert 23, projects 
coaxially downwards. It bears a sealing ring 83, which fits in sealing 
manner on the outer end face of the pouring nozzle 19. At its outer 
periphery, the sealing ring 83 is gripped by the inner surface of a 
coaxial, downward-projecting step 84. In the closed condition, the step 84 
is at no spacing or only a very small spacing from the end face 86 of the 
coaxial inner rim 67. This means that the underside 87 can act as a 
compression-limiting surface for the sealing ring 83 and can at the same 
time also transmit impact forces to the inner rim 67. Outside of the 
underside, the cap 31 has an outer rim 88, the inner surface 89 of which 
lies on a diameter which is only slightly greater than the diameter of the 
outer surface 70 of the coaxial inner rim 67 at the bottom, the inner 
surface 89 runs into a 45.degree. bezel 91 which, in cooperation with the 
bezel 69, produces precentering upon closing. Outside the bezel 91, there 
is an annular surface 92 which lies perpendicular to the longitudinal axis 
33 and can receive support on the supporting ledge 68 in the event of 
overloads. At the front, the outer surface 93 of the outer rim 88 runs 
coaxial to the axis 33 and is flush with the outer surface 36 of the body 
34 in the closed condition, as is shown by FIGS. 4, 6 and 8. Here too, 
flattened portions 94 and 96, which lie perpendicular to the central plane 
44 and, in the view shown in FIG. 6 for example, are in alignement with 
one another in the closed condition, are provided in a manner 
corresponding to the outline of the body 34. In a similar manner, the 
flattened portions 94, 96 merge into tapering surfaces 97, 98 which, in 
the closed condition, are in alignment with the tapering surfaces 42, 43. 
From the plane of the annular surface 92 there extend downwards two 
gudgeons 99, 101. Since both are exact mirror images of one another in 
shape, only gudgeon 99 is described. Its front surface 102 lies parallel 
to the central plane 44 and, in the closed condition, virtually lies 
against the rear surface 46 of the body 34. In the closed condition, its 
underside 103 lies at the level of the underside 52 of the body 34. Its 
inner surface 104 lies perpendicular to the central plane 44 and is at 
only a short spacing from the end surface 49. Its rear surface 106 runs 
flush with the rear surface 56. There is also a radiused portion 
corresponding to the radiused portion 54. Because of the position of the 
inner surface 104 and the planar tapering surface 97 extending into the 
gudgeon 99, the gudgeon 99 is conically tapered towards the rear, as shown 
with particular clarity in FIG. 8. The gudgeon 99 has an approximately 
heart-shaped recess 107, the tip of which points upwards and backwards 
towards the right according to FIG. 4. In the closed condition, one end of 
the metal Din 62 lies in the rear indentation 108 which lies at a somewhat 
lower level according to FIG. 4. When the cap 31 is open, the free end of 
the metal pin 62 lies in the indentation 109 which, in FIG. 4, is further 
forward and at a somewhat higher level and, in this state, the edge 58 
lies against the annular surface 92 in that region. At the rear, the cap 
31 ends with a rear surface 111 arranged between the inner surfaces 104 
this surface is not quite perpendicular to the plane of projection of FIG. 
6 but slopes forward somewhat. Since it also begins somewhat further 
forward than the rear surface 56 of the body 34 it enables the hinge block 
48 to be seen. The rear surface 111 can come into being because the volume 
of the cap is drawn rearwards in the region 112 in a manner similar to the 
hinge block 48. In this region 112, the underside of the cap 31 is at only 
a very small spacing from the end surface 69, enabling these surfaces too 
to fit together snugly. Above the outer rim 88 and the step 84, a bead 113 
rises above the cap base 81, said bead being 5 mm high, having a radiused 
portion of 4 mm, being rounded towards the top and its outer surface 
conforming to the tapered surfaces 97, 98 so that, looking from above in 
the direction of the longitudinal axis 33, nothing is seen protruding and, 
in the closed condition, the smooth surface which can be seen in 
particular in FIG. 4 but also in FIGS. 5, 6, 8 and 9 is produced. Journals 
114, 116 which are approximately as long as the rounded tips 74, project 
beyond the flattened portions 94, 96, being directly above the rounded tip 
74 and in the central plane 44 in the closed condition. The center of the 
journals 114, 116 is approximately at the level of the underside 87 so 
that in material terms they have towards the top a material bridge to the 
base/bead region and, in the event of downward bending, are partially 
linked to this region, as shown to the outside right in FIG. 9. 
The upper edge of the outer handles 14, 16 and the central handle 13 define 
a stacking surface 117. In this plane, the cap 31 has a flattened portion 
118, as can be seen particularly clearly from FIG. 6, and since, as seen 
from the top, the cap 31 has the approximate outline of a horse shoe and 
the rear surface 111 is set forward, the flattened portion 118 has an 
approximately H-shaped form as viewed in FIG. 6 wich a broad central 
region which, within the sidepieces of the H, has been displaced upwards. 
In the view in FIG. 9, this produces the strange-looking but nevertheless 
correctly represented perspective view. 
The claw 32 comprises a gripping web 119, two lateral webs 121, 122 and in 
each case an upper prong 123 and a lower prong 124. The gripping web 119 
is sufficiently wide to extend on each side far beyond the central handle 
13, half way towards the outer handles 14, 16. A gripping depression 126 
is molded into it from above. In the closed condition, its upper side 127 
lies flush with the stacking surface 117, it thus also lies flush with the 
flattened portion 118 of the cap 31. With a view to walls of uniform 
thickness but also to enable the gripping web 119 to be grasped more 
easily from below and also to be able to exert forces more easily, the 
gripping web 119 has a downward-directed curvature 128 which, towards the 
rear, ends with a blunt rounded portion 129. In the closed condition, a 
longitudinal edge 131 lies on the hinge block 84 approximately in the 
region of the edge 58 and an extension of this longitudinal edge 131 also 
lies on the gudgeons 99, 101 or the longitudinal edge 131 is at a very 
small spacing from the latter. According to FIG. 6, the lateral webs 121, 
122 splay out following the angle of the tapering surfaces 97, 98, the 
angles of which are equal to those of the tapering surfaces 42, 43. Since 
the lateral webs 21, 22 are exact mirror images of each other, only one of 
them is described. The inner surface 132, of the lateral web 121 follows 
closely the tapering surface 98, having a very slight spacing from the 
latter. As seen from above, both it and its prongs 123, 124 are 11 mm wide 
and, as seen from the side, 15 mm high. This cross-section is sufficient 
even when the claw 32 has been injection-molded from plastic. The 
transition between the lateral web 121 and the upper and lower prongs 123, 
124 is formed by a central area 133 which, according to the figures, is 
broad and inflexible. According to FIG. 4, the upper side 134 of the upper 
prong 123 runs approximately 4 mm below the bead 113 at that point in the 
closed condition. To the left, the upper prong 123 ends with a large 10 mm 
radiused portion 136. The underside 137 of the prong 123 extends on a 
level with the annular surface 92 of the cap 31. In the upper prong 123, 
there is a through bore 138 through which the journal 114 passes. The 
underside 139 of the lower prong rests on a large 30 mm radiused portion 
which has its center in the center of the through bore 138. In its upper 
region, the lower pronged 134 and the central area 133 together cover the 
parting line between the body 34 and the cap 131 in the region lying 
therebelow. The upper prong 133 and the lower prong 134 have a minimum 
spacing from the flattened portion 94 and 39 respectively and thus fit 
close to the latter. The front side 141 runs parallel to the central plane 
44 and extends exactly as far forwards as the forward-most point of the 
radiused portion 136 and of the abutment 37. Perpendicular to the front 
side 41 and directed inwards there is short planar upper side 142 whose 
position is such that, during the closure of the claw 32, its forward 
region fits under the rounded portion 74, at first without the exertion of 
force, and rests against it. As the claw 32 is moved further towards the 
closed position, tension is produced which forces the lower prong 124 
downwards. During these swivelling movements of the claw 32, the sealing 
ring 143 is compressed between the front face of the insert 23 and the 
base 81 of the cap 31. 
Inwards of the upper side 142 there is a 2 mm deep locking groove 144, the 
shape of which corresponds to the rounded tip 74. In the closed condition, 
this locks into the locking groove 144, the force being determined by the 
degree to which the sealing ring 83 is compressed. 
There follows on from the locking groove 144 an oblique surface 146 which 
slopes upwards to the right at 45.degree. and, in the closed condition, 
rests against the stop surface 77 and has a shape which is complimentary 
to the latter. The oblique surface 146 and the underside 137 meet at a 
rounded portion 147. 
In so far as radiused portions are of no special importance, they are 
formed by injection molding and have a maximum radius of 3 mm. 
As can be understood from the description, but in particular also from 
FIGS. 4, 5, 6 and 8, a closure 28 has been successfully designed such 
that, in the critical closed condition, each part supports and protects 
the other so that randomly occurring impacts and forces are absorbed by a 
plurality of parts. In addition, care has been taken to ensure that parts 
do not protrude in a detrimental way since this could lead to the opening 
of the closure. If the canister 12 falls on the stacking surface 117, the 
principle forces are absorbed by the handles. The general thinking behind 
the closure enables the sometimes crude forces to be absorbed even when 
all the parts have been injection-molded in a plastic. Despite being very 
convenient to handle, the closure 28 is of flat construction and is 
relatively broad and long, this being very advantageous under the various 
operating conditions. 
The geometry of the cap 31, claw 32 and abutment 71, 72 also produces 
another advantageous improvement in functioning: For certain reasons, it 
may not be possible to open the cap 31, whether it is because, for 
example, it has stuck or frozen to some degree to the cap 31 or is 
difficult to open for some other reason (e.g. the external air pressure is 
too great). In this case, the claw 32 is swivelled by about another 
180.degree. out of its unlocked position in the direction of opening. 
During this operation, the upper side of the upper prong 123 comes to rest 
on the upper side of the abutments 71, 72 and, if the claw 32 is moved 
further, the cap 31 opens a crack, this being quite sufficient for pulling 
it off.