Push button safety cap for containers

A two component rotational safety cap for containers of harmful substances is disclosed. The cap is more positive and more reliable in its operation. It has several false depressed push button positions during unscrewing rotation to confuse children and a single unscrewing depressed location of the push button corresponding with alignment of two visual indicator elements on the cap components to facilitate cap unscrewing by adult users without difficulty or discomfort. The safety cap has only a single positive tightening element on each cap component, one of which elements is a spring ramp element on the inner cap component whose elevation relative to the outer cap component is controlled by fixed ramps on the outer cap component.

BACKGROUND OF THE INVENTION 
This invention in general has the same objectives and advantages described 
in U.S. Pat. No. 4,223,794 and in the above-referenced copending 
application. 
Additionally, the present invention seeks to provide a safety or 
child-proof closure cap which is even more confusing to children seeking 
to open it and which has a more positive, reliable and less confusing mode 
of operation when used by adults. 
In accomplishing these aims, a two component rotational safety cap for 
containers of harmful substances is provided which during the opening or 
unscrewing mode has several false depressed push button positions which 
cannot produce release of the closure cap, thus further confusing 
children, and a single true depressed push button position which produces 
cap release in an easy and comfortable manner by an adult. 
Additionally, the present invention provides a safety cap which possesses 
only a single positive and reliable engaging tightening element on each 
rotational cap component, one of which elements is a spring ramp element 
on the inner cap component which has interlocking relationship in a secure 
manner with a fixed abutment element on the outer cap component to enable 
secure tightening of the safety cap. The spring ramp serves the dual 
purpose of engaging a lug or tooth on the bottom of the push button to 
elevate the push button to indicate that the closure cap is in a safe or 
child-resistant condition. Positive camming means is provided on the outer 
cap component to contact and depress the spring ramp element to an 
elevation whereby the spring ramp element will not interfere with 
desirable rotation of the outer cap component in either direction. 
Other benefits and advantages of the invention will appear to those skilled 
in the art during the course of the following detailed description.

DETAILED DESCRIPTION 
Referring to the drawings in detail wherein like numerals designate like 
parts, a container 20 such as a typical glass or plastics medicine 
container includes a threaded neck 21 which is engaged by the internal 
screw-threads 22 of an interior generally cylindrical safety cap component 
23 including a top wall 24. A suitable seal 25 is interposed between the 
wall 24 and the end face of container neck 21, as shown. 
An outer safety cap component 26 of cylindrical form engages telescopically 
over the inner cap component 23, as best shown in FIG. 4, and a rotational 
connection between the two cap components is maintained through the 
interfitting of an internal annular bead 27 on the component 26 with a 
mating annular groove 28 of the component 23. This detent arrangement 
maintains the two cap components permanently assembled through snap action 
while allowing free relative rotation between them, except as constrained 
by elements of the invention, to be described. The outer component 26 
contains no screw-threads. It is preferably knurled or ribbed on the 
exterior of its side wall. 
To provide maximum lateral stability between the two components to prevent 
binding and promote ease of operation, a ring extension 29 on the top wall 
24 of inner cap component 23 receives, in close fitting relationship, a 
smaller depending ring extension 30 of the outer component 26. 
Additionally, the latter may also have a smaller concentric ring 31 
engaging over a center axial post 32 rising from the interior cap 
component. 
The outer component 26 has a top wall well 33 for a push button tab 34 
having an integral lower side depending radial lug or tooth 35 which 
extends from the periphery of the tab 34 inwardly to a point near the 
center of the push button tab. The tab 34 is preferably connected to the 
cap component 26 through a radial thin strip 36 which is hinged at 37, 
FIG. 4, to the side wall of the outer cap component. The component 26 has 
a top wall groove 38 to receive the attaching strip 36, as best shown in 
FIG. 4. The strip 36 and groove 38 could be omitted, if desired. 
Each cap component 23 and 26 has a radially projecting visual indicator 
element 39 at the bottom of its side wall to enable an adult user of the 
container to know at a glance that the safety closure cap is in a 
releasable condition, as will be further explained. The two indicator 
elements 39 are in superposed alignment at this time. A blind user of the 
container can detect by feel when the elements 39 are in alignment to 
permit unscrewing of the closure cap. 
The heart of the invention, now to be described, comprises on the inner cap 
component 23 a vertical unscrewing abutment surface 40 on one side of a 
fixed lug 41 attached to top wall 24 and having on its other side an 
inclined ramp surface 42 adapted to be cammingly engaged by the depending 
lug 35 of push button tab 34. Another fixed lug 43 rises from the top wall 
24 to the same height as the lug 41 and has opposite side ramp faces 44 
and 45 which can engage and elevate the push button lug 35 at certain 
times. An additional stationary upstanding lug 46 on the top wall 24 
having the same height as the lugs 41 and 43 includes one inclined ramp 
surface 47 spaced approximately 180 degrees from the ramp surface 45. 
Between the circumferentially spaced lugs 41 and 46, an arcuate 
cantilevered spring ramp element 48 rises from the top wall 24. The bottom 
of the spring ramp element is adjacent to the fixed lug 41 while its top 
is near the lug 46 and slightly above this lug, FIG. 10, when the element 
48 is in a relaxed state. The free end of spring ramp element 48 has a 
right angular locking notch 49 formed therein, for a purpose to be fully 
described. 
It is to be noted that the several fixed lugs 41, 43 and 46 of cap 
component 23 lie on a common circumference of one radius. The spring ramp 
element 48, while lying on the same circumference as the three fixed lugs, 
is radially wider than the lugs and therefore projects radially beyond the 
lugs, as best shown in FIG. 5, for a reason to be explained. 
Also, as a part of the essence of the invention, the outer component 26 of 
the safety cap has a gradually inclined narrow ramp 50 descending from its 
top wall 51 and having its lowest portion adjacent to the bottom face of 
the well 33, FIGS. 6 and 9. A short extension 52 of this ramp or cam 50 
descends from the bottom face of the well 33 to an elevation slightly 
below the tops of the three fixed lugs 41, 43 and 46 in the assembled 
relationship of the two cap components, FIGS. 11C and 12. The lowermost 
end of short ramp 52 terminates at one side of a slot 53 in the bottom 
wall of well 33, which slot receives the depending lug or tooth 35 of push 
button tab 34. It should be noted that the ramp extension 52 is closely 
addacent to the interior of the cylindrical side wall 54 of outer cap 
component 26 so as to lie in the path of that portion of the leading end 
of spring ramp 48 which is radially outside of the three stationary lugs 
41, 43 and 46, as above-described. 
The operation of the push button safety cap can best be described with 
reference to FIGS. 10, 11A through 11C and 12. FIG. 10 in full lines 
depicts the relationship of inner and outer cap components 23 and 26 in 
the unscrewing or opening of the safety cap. Assuming the cap to be 
secured on the container 20 in a firm manner and an adult user wishes to 
open the container, such user can rotate the outer component 26 
counterclockwise, FIG. 2, or in the direction of the arrow 55, FIG. 10, 
until the indicator elements 39 are in alignment one above the other. The 
user will then know that push button tab 34 can be depressed in the well 
33 to the position shown in FIG. 10 where the depending lug 35 is well 
below the top of fixed lug 41 and in opposed relationship to the 
unscrewing abutment surface 40. Further turning of outer component 26 in 
the direction of arrow 55 will bring lug 35 into engagement with abutment 
surface 40 while the push button tab remains depressed and will cause the 
unscrewing and release of the inner cap component 23 from the container 20 
along with the outer cap component. 
It should be noted that, as in the referenced pending application, the push 
button tab 34 is constrained in its depressed active position, FIG. 4, by 
lower detent ribs 56 of the well 33 and is constrained in the raised 
inactive position, FIGS. 11B and 11C, by being between the ribs 56 and 
coacting upper detent ribs 57. This renders the action of the push button 
tab 34 more positive and more controllable by the adult user. When 
depressed, as in FIG. 4, the lug 35 is well below the tops of fixed lugs 
41, 43 and 46. When elevated by the camming action of ramp surfaces 42, 
45, 47 and 48, the bottom of lug 35 is above and can clear the tops of the 
fixed lugs on inner component 23, as shown for example in FIG. 11B. 
Still referring primarily to FIG. 10, a child attempting to unscrew the 
safety cap will normally turn the outer component 26 counterclockwise 
without depressing push button tab 34 and the outer component will spin 
freely and no release of the cap will be accomplished. If the child 
happens to depress the push button tab 34, the latter will assume four 
false depressed positions during rotation of the outer component 26 
allowed by the spaces between fixed lugs 41, 43 and 46 and the space 
between spring ramp 48 and lug 41. The false depressed positions of the 
push button lug 35 are shown in broken lines in FIG. 10. True active 
depressed position of lug 35 opposite abutment surface 40 is shown in full 
lines in FIG. 10. A child will be unlikely to find the active or true 
depressed position of the push button shown in FIG. 10 because he will not 
understand the indicating relationship of the elements 39. Thus, the 
invention in the unscrewing mode of operation offers further confusion for 
a child seeking to open the safety cap compared to the prior art. 
The operation of down screwing and securing the safety cap is depicted in 
FIGS. 11A through 11C. In FIG. 11A, the user begins turning the outer cap 
component 26 clockwise, FIG. 2, and in the direction of the arrow 58. 
Initially, the lug 35 of the push button depressed by the prior unscrewing 
of the cap will engage ramp surface 44 lightly and the inner component 23 
of the cap will start to rotate with the outer component 26 in the same 
direction as the latter shown by the arrow 58'. Following increased 
resistance caused by the screw-threads 22 of cap component 23, the 
depressed lug 35 will ride up on the ramp surface 44 to the elevated 
position shown in FIG. 11B, and the outer component 26 will continue 
rotating in the direction of the arrow 59 while the inner component 23 
will resist rotation. This is the second stage of the screw-down operation 
shown in FIG. 11B. 
The third and final stage of tightening of the safety cap is shown in FIG. 
11C. The outer component 26 has advanced in relation to the inner 
component 23 in the screwing down process until a square notch 60 formed 
in one side of the floor defined by groove 38 engages and interlocks with 
the square locking notch 49 in the leading end of the spring ramp 48. This 
positive engagement from which the spring ramp element 48 cannot escape 
causes both cap components 26 and 23 to rotate as a unit, as shown by the 
arrows 61 until final tightening of the safety cap is accomplished, at 
which time the outer cap component 26 is free-turning in the unscrewing 
direction for the safety of children seeking to release the cap. 
FIG. 12 depicts the operation of the described camming means 50 and 52 on 
the outer cap component 26 to assure that the upper extremity of spring 
ramp element 48 will not impede free rotation of the outer component in 
either direction indicated by the arrows 62, at times other than during 
the final cap tightening process shown in FIG. 11C. During such relative 
rotation in either direction of the outer component 26, the gradual cam 50 
depending from the top wall 51 will first act on the spring ramp element 
48 to bend and depress it, followed by a similar action of the cam 52 
which, in effect, is an extension of the cam 50 to depress the element 48 
below the tops of fixed lugs 41, 43 and 46. This assures that the 
depending drive lug 35 of push button tab 34 will not catch and hang up on 
the spring ramp element 48, as shown in FIG. 12. In the operation of the 
safety cap, the only tightening engagement between the two components 26 
and 23 in the final tightening stage, FIG. 11C, is the engagement of the 
two notches 49 and 60 in a secure interlocking manner. This single 
position positive tightening engagement of the two cap components is a 
feature of the invention. The camming means 50 and 52 is necessary to 
preclude any other faulty or undesirable driving engagement through the 
spring ramp element 48. 
It should be noted that the engagement of cams 50 and 52 with element 48 
occurs near the periphery of the cap and outside of the circumferential 
path on which the fixed lugs 41, 43 and 46 are located. This is why the 
spring ramp element 48 is radially wider and extends radially outside of 
the lugs 41, 43 and 46 to be engageable by cams 50 and 52, which latter 
cam is also radially outwardly of the fixed lugs of component 23. 
It may now be seen that an efficient and reliable safety cap is provided by 
the invention which is more confusing to children due to the several false 
depressed positions of the push button, and less confusing and easier to 
operate by adults mainly due to a single position positive tightening 
engagement between the two components shown in FIG. 11C. The device is 
entirely practical from the standpoint of modern plastics molding 
techniques. 
The terms and expressions which have been employed herein are used as terms 
of description and not of limitation, and there is no intention, in the 
use of such terms and expressions, of excluding any equivalents of the 
features shown and described or portions thereof but it is recognized that 
various modifications are possible within the scope of the invention 
claimed.