Ratchet-type safety closure

Abstract

The invention contemplates a safety closure cap and necked bottle having coacting features of threaded and ratchet-locking engagement. In a preferred form, the ratchet-locking element of the bottle includes two diametrically opposed radially outwardly cantilevered wing members each having an upwardly directed ratchet tooth and integrally formed with the bottle neck. Each ratchet tooth has ratchet engagement with ratchet-tooth formations within the skirt of the closure cap, and each wing member is axially downwardly deflected in the course of securing the cap to the bottle, so as to resiliently load the wing member into arcuately extensive stabilizing contact with the skirt for a fully engaged relation of the ratchet-engaged parts. By having the ratchet teeth on the wing members at other than an integer multiple of the basic periodicity of tooth formations on the cap, it is possible to offer more ratchet-lockable angular positions, per revolution of the cap, than there are tooth formations in the cap.

Description

This invention relates to bottles or the like containers adapted to contain hazardous substances, and more particularly relates to safety closures for such containers which render them child-resistant, i.e., resistant to tampering by children.

It is an object of the invention to provide a new and improved neck construction for such a container, particularly to receive and ratchet-lock a safety cap of the variety having rotary engagement to the neck, as by threads.

Another object of the invention is to provide a new and improved bottle construction integrally incorporating a safety lock feature without detriment to manufacturing economy and readily lending itself to automatic production-line facilities for filling and capping a bottle.

A further object of the invention is to provide a new and improved safety cap and bottle combination in which the cap is readily locked onto the bottle but may be unlocked therefrom by a very simple manipulation of a part of the bottle itself.

A still further object is to meet the above objects with a construction of inherent low cost, involving minimum alteration of present constructions.

It is a specific object to provide the above-noted features in application to injection-blow-molding of plastic containers, and involving minimal change in container molds.

Another specific object is to meet the above objects with structure requiring no additional parts but rather involving simple modification of existing bottle and cap parts.

Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the following specification in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, a preferred form of the invention:

FIG. 1 is a perspective view of assembled and safety-locked cap and bottle parts of the invention;

FIG. 2 is a view in side elevation of neck formations of the bottle of FIG. 1;

FIG. 3 is a plan view of neck formations of FIG. 2;

FIG. 4 is a vertical sectional view of the cap of FIG. 1;

FIG. 5 is a side-elevational view of the bottle-neck region, the aspect being normal to the parting line identified in FIG. 3;

FIGS. 6 and 7 are similar enlarged fragmentary sectional views to illustrate successive relations of cap positioning on the neck, for the parts of FIG. 1; and

FIG. 8 is a greatly enlarged fragmentary view, partly broken away and in section, along line 8--8 of FIG. 7, to illustrate a ratchet-tooth engagement.

Referring to the drawings, the invention is shown in application to a container or bottle 10 having an integral threaded neck 11 and selectively opened and closed by a cap having a threaded bore 13. The bottle may be of any plastic material suitable for injection-blow-molded manufacture, and high-density polyethylene is indicated as such a material. In such manufacture, the entire neck region 11 is defined by an injection-type two-part mold such that each half of the mold defines a generally semi-cylindrical half of the bottle, with symmetry about a parting line which includes the neck axis, as suggested by legend in FIG. 3. Cap 12 may be of any suitable construction, being typically an injection-molded part, for the case of a plastic bottle 10.

In the preferred embodiment of the invention, the neck region of the bottle, at the base end of the threads, is integrally formed with two ratchet-wing members or tabs 14-15, at diametrically opposite locations and in axially offset relation to the bulbous enlargement of the adjacent upper body part of the bottle. A single ratchet tooth 16 on each of these members faces upwardly for ratchet engagement with downwardly facing ratchet-tooth formations 17 distributed circumferentially about the lower end of the bore of the cap; stated in other words, the formations 17 characterize a counterbore within the skirt 18 by which the open end of the cap is smoothly and continuously defined. The outer end 19 of each wing member projects externally of the applied cap and is preferably upwardly flanged in axially overlapping and radial-clearance relation with the adjacent skirt surface 18.

More specifically, each wing member or tab 14 (15) is generally flat, having a transverse section characterized by substantially greater width W than thickness T and oriented so that the upper surface can have smooth and relatively extensive stabilizing contact with the lower edge of skirt 18, such contact being of course applicable for a fully-engaged ratchet condition. Also, the upward projecting extent or height H of the ratchet tooth 16 is preferably slightly less than the depth D of each of the tooth formations 17 of the cap, so that in the engaged condition (see FIG. 8), a clearance 20 exists while the flat upper surface 21 of member 14 is in full contact with skirt 18. Typically, the sectional proportions are such that W is in the order of 5 times T, thus favoring essentially only axially compliant deflection of the cantilevered end of each tab, and the tab width W is several times the effective width W' of ratchet tooth 14, for example in the order of 4 times the tooth width. Additionally, in the unstressed state, i.e., prior to cap contact with either of the tabs (FIG. 6), the tabs 14-15 are upwardly inclined to an extent .alpha. above a radial plane through the neck region, and the juncture to the neck is selected to provide substantial take-up (reduction) of the angle .alpha. in the course of achieving a cap-closed condition of the container (FIG. 7). Still further, the locking face 22 of tooth 16 is centrally positioned with respect to the width dimension W and is also coincident with the parting line (see FIG. 3) so as to provide clean definition of the surface which must bear the brunt of any attempted unthreading of the cap, for a ratchet-engaged condition.

In the operation of the device, cap placement and its threaded advance on neck 11 drives the lower end into escaping ratchet engagement with teeth 16, the inclination angle .alpha. being reduced as compliant reaction develops in approach to the fully closed condition (FIG. 7). The cap is locked and cannot be unthreaded, in the absence of deliberate downward deflection of both finger flanges 19. Unauthorized attempted unthreading (i.e., while ratchet-engaged) is met with firmly stabilized resistance by the locking-face engagement at 22, it being noted that the effective center of such resistance is close to (i.e., is offset very little from) the tab surface 21 and that the adjacent lateral supporting extent (designated W/2 in FIG. 8) of surface 21 is several times the offset of said effective center.

If the number of ratchet-tooth formations 17 is even, and the teeth 16 are in true diametrically opposed relation, then teeth 16 of both wing members 14-15 will operate in unison, to provide as many ratchet-lockable positions per cap revolution as there are tooth formations 17. If on the other hand, the number of formations 17 is odd, then teeth 16 of wing members 14-15 will operate in interlaced alternation, providing twice as many ratchet-lockable positions per cap revolution as there are tooth formations 17. Stated in other words, such a staggered interlace of ratchet actions enables a finer angular precision with which a given closed condition of the container can be held. The criterion for such interlace action is that the teeth 16 shall be angularly spaced by an odd-integer multiple of one half the effective angular spacing of adjacent formations 17, while for teeth 16 ratcheting in unison such angular spacing is at an integer multiple of the spacing between adjacent formations 17.

In further illustration of the invention, I shall set forth pertinent illustrative dimensions for the case of a container having a neck with two turns of helical threads, radially raised from a cylindrical neck surface of 0.990-inch diameter, the threaded extent being 0.450 inch along the outer end of the neck. The wing members 14-15 extend to a maximum unstressed span of 1.850 inch, measured across flanges 19. Teeth 16 are 0.060-inch wide by 0.060-inch high and are supported by a tab section 0.250-inch wide and 0.040-inch thick, being defined between inner radii of 0.670 and 0.730 inch. Cooperating with such is a cap 12 of 1.550-inch diameter at skirt 19, and with 23 or 24 tooth formations 17, depending upon whether interlaced or unison ratcheting is desired.

The described structure will be seen to have achieved all stated objects. It represents the essence of parts simplicity and of number of parts, and yet a fine degree of ratchet positioning is available without reducing the size of teeth 16 or formations 17. The ratchet-tab formations 14-15 are produced as relatively simple modification (for example, by EDM-milling at the parting-line region) of existing injection-blow-molding mold halves.

While the invention has been described in detail for the preferred form shown, it will be understood that modifications may be made without departure from the claimed scope of the invention.

Claims

What is claimed is:

1. In combination, a bottle or the like having a body with an externally threaded neck, and a safety cap with a body having a threaded bore to removably engage said neck, the open end of said cap body having a counterbore comprising a circumferential succession of downwardly exposed axially undulating ratchet-tooth formations within a circumferentially continuous skirt, and said neck being integrally formed with two axially compliant radially outward ratchet wing members at diametrically opposed locations beneath and adjacent the open end of said cap body when the neck is closed by said cap, each wing member extending radially outward of said skirt for manual access and comprising a substantially flat element having a transverse section that is substantially greater in width than in thickness, each wing member being continuously formed with said neck in such orientation that the width dimension of the wing member extends over an arc about the neck axis, whereby axially compliant flexure of the cantilevered outer end of each wing member is the favored mode of wing-member deflection, an upwardly projecting ratchet tooth integrally formed with the upper surface of each wing member at the location of radial registry with ratchet-tooth formations of said cap, the axial extent of upward projection of said ratchet teeth being less than the axial depth of said ratchet-tooth formations, whereby for each ratcheted engagement the associated wing member is stabilized by relatively extensive continuous arcuate contact with said skirt, thus preventing bottoming contact of the ratchet tooth in any of the ratchet-tooth formations of said cap.

2. The combination of claim 1, in which each said ratchet tooth has an effective width that is a relatively small fraction of the effective width of its associated wing member.

3. The combination of claim 1, in which each said ratchet tooth is centrally located with respect to the width dimension of its associated wing member.

4. The combination of claim 1, in which each said ratchet tooth has a sloping ramp face and an axially extending locking face, said ramp face being centrally located with respect to the width dimension of the associated wing member.

5. The combination of claim 1, in which each wing member in its unstressed state is cantilevered in an axially upward inclined orientation and is so positioned that it is downwardly deflected in approach to substantially a horizontal radial plane upon fully ratcheted cap closure of said neck.

6. The combination of claim 1, in which that part of each said wing member which extends beyond said skirt includes an axially upward flange in axially overlapping and radially clearing relation with said skirt.

7. The combination of claim 2, in which said fraction is substantially one fourth.

8. The combination of claim 1, in which the proportion by which the wing-member width exceeds its thickness is in the order of 5:1.

9. The combination of claim 5, in which said unstressed inclination is in the order of 10.degree. above a radial plane of said neck.

10. As an article of manufacture, a unitary integrally formed injection-blow-molded plastic bottle having an injection molded externally threaded bottle-neck portion and a blow-molded bottle-body portion, said injection-molded bottle-neck portion integrally including a ratchet wing member projecting radially outwardly from a location axially below the threaded region, said wing member being substantially flat and having a transverse section that is substantially greater in width than in thickness, the width dimension of said wing member being so oriented as to extend over an arc about the neck axis, whereby axially compliant flexure of the cantilevered outer end is the favored mode of wing-member deflection, and an upwardly projecting ratchet tooth integrally formed with the upper surface of the wing member at a location radially offset from said neck portion.