Child resistant closures
United States Patent 1 Curry et al.  
  111 3,8,78,9 ,5 Apr. 22, 1975 CHILD RESISTANT CLOSURES [75] Inventors: John Joseph Curry, Westchester; Carl William Lange, Des Plaines, both of 111.  
 [73] Assignee: Illinois Tool Works Inc., Chicago.  
 [22] Filed: Dec. 28, 1973 [21] Appl. No.: 429,463  
 [52] 0.8. CI. 215/219 [51] Int. Cl..... B65d /02; Bd /56; A6lj 1/00 [58] Field of Search 215/9, 219, 220  
 [56] References Cited UNITED STATES PATENTS 3,679,085 7/1972 Ciach 215/220 3.830.390 8/1974 Gach 215/9 Primary Examiner-George T. Hall Attorney, Agent, or Firm-Robert W. Beart; Edward L. Benno 5 7 ABSTRACT A threaded safety closure assembly for sealing threaded bottles or other containers with contents which might be harmful to children. the closure&#39;assembly including an inner cap and an overcap rotatable relative to the inner cap in unscrewing direction, as counterclockwise, except with selected pressure applied by an adult to effect interengagement between the two caps for opening movement thereof in unison permitting intentional access to the container contents; and the closure assembly having improved top drive interengagement between the caps in the closing direction, as clockwise, for use in capping machines applying a relatively high torque for effectively sealing the containers in hermetic fashion without tendency for the interengaged drive to frictionally weld or set under the applied torque and permit. as a result thereof, opening rotation of the closure assembly and rendering of the safety features inoperative for the intended purpose.  
 9 Claims, 8 Drawing Figures l l 22 2s I4 38 l2 6,. IO I I!&#34; V CHILD RESISTANT CLOSURES The present invention is concerned with a safety closure assembly formed &#39;of suitable plastic material. preferably aresilient material, and including an internally threaded inner cap and an overcap with engageable driving abutments between the tops of the caps brought into operation byautomatic capping machines applying relatively high torque to threadedly engage the closure assembly with a bottle or other container for hermetically sealing the same with provision made for guarding against jamming or fixation between the driving abutments under the applied torque so as to insure proper functioning of adult manipulation of the overcap to effect engagement thereof with the inner cap for turning the two caps as a unit assembly in a counterclockwise direction for unscrewing the same for the container.  
  In the prior art, there are many forms of safety closures designed to prevent or render it difficult for children to remove the same from bottles and the like containing medicines or other contents which might be harmful without supervision. There are those requiring implements for removing the closures and those requiring some undisclosed, and not readily apparent manipulation of the closure before it can be removed or unscrewed from the associated container, and various other types. Among those requiring some manipulation of the closure, there is the type including an inner cap for threaded engagement with a container and an overcap which will rotate relative to the inner cap in counterclockwise unscrewing direction but which may be manipulated by an adult to effect interengagement between the two caps for opening rotation of the closure assembly. This interengagement between two caps is often accomplished by some axial movement of the overcap relative to the inner cap or by a squeezing pressure application of force to selected portions of the overcap. In the latter type, there is often no provision made for the application of high torque closing of the container in automatic capping machines in a manner which will insure proper functioning of the safety opening arrangement for gaining intentional access to the contents of the container.  
  An object of the invention is to provide a threaded safety closure assembly of the double cap type which may be initially applied to a container under relatively high torque for hermetic sealing by automatic capping machines without affecting the later functioning of safety opening by manipulation of the overcap to effect opening rotation of the closure assembly.  
  Another object of the invention is to provide a safety closure assembly of the above type with interengageable driving abutment means between the top of the two caps and through which the caps are rotated in unison in the closing direction by the capping machines but with the abutment means relieved along their trailing surfaces to present only substantially line contact with the adjacent surfaces of the inner cap and overcap, respectively, thus reducing to a minimum frictional surface engagement which might tend to set under storage conditions or under high top loading and handling conditions.  
  A further object of the invention is to provide a safety closure of the above type wherein the cap skirts are provided with interengaging means upon pressure application to &#34;the overcap skirt for opening rotation of the closure assembly and with permissive trapped axial movement of the overcap relative to the inner cap upon opening direction rotation of the overcap relative to the inner with the driving abutments ratcheting by one another.  
  The above and other objects of the invention will in part be obvious and will be hereinafter more fully pointed out in the following detailed description of the drawings in which FIG. 1 is a perspective view, partly in section, showing one form of closure assembly in sealed position on a bottle;  
 FIG. 2 is a top plan view of the inner cap;  
  FIG. 3 is a side elevation, partly in section on the line 3-3 of FIG. 2, of the inner cap;  
 FIG. 4 is a top plan view, partly in section, of the overcap; 7  
  FIG. 5 is a fragmentary sectional view showing the axially elevated position of the overcap as the driving abutments ratchet by one another upon opening direction rotation of the overcap relative to the inner cap;  
  FIG. 6 is a top plan view of a modified form of overcap;  
  FIG. 7 is a perspective view, partly in section, showing the overcap of FIG. 6 in the closure assembly in sealed position on a bottle, and  
  FIG. 8 is a fragmentary sectional view, similar to FIG. 5, showing the axially elevated position of the closure assembly of FIG. 7.  
  With reference to the drawings, and particularly FIGS. 1 to 4 at this time, the closure assembly is shown applied to a bottle 10 (FIG. ll) having a neck portion 12 with external threads 14. The safety closure assembly includes an inner cap 16 nested within an outer or overcap 18 formed of suitable materials such as metals or plastics. In one preferred embodiment a plastic such as polypropylene was used for the inner cap and a resilient material such as polyethylene was used for the outer cap. The inner cap includesa top closing wall 20 with the inner surface recessed to receivea suitable sealing disc or liner 22 of pulp and vinylite adhered therein and adapted to hermetically seal the bottleby engagement with the lip: of the bottle neck 12. The inner cap has a depending skirt or flange 24 terminating in an outward shoulder 26 which need not be peripherally continuous and the inner surface of the skirt is provided with thread formations 28 cooperating with the threads 14 on the bottle neck. The outer surface of the skirt 24 is provided with circumferentially spaced vertically extending ribs 25 serving as teeth for engagement with cooperating means on the outer cap as will be explained. The outer surface of the closing wall 20 is provided with a peripheral upstanding rib&#39;30 serving as the primary support for the outer cap, and upstanding spaced lugs or teeth 32 which serve as driving abutment means for tightening the: inner cap in the closing direction of rotation thereof as will be described hereinafter. These driving lugs or teeth may vary in number and circumferential spacing and each is provided with a substantially vertical abutment surface 32a and a curved downwardly or otherwise relieved leading surface 32b as shown in FIG. 3.  
  The outer or overcap 18 has atop closing wall 34 and a depending peripheral skirt or flange 36 with a lower wall portion 38 of lesser thickness and more resiliency which terminates in an inwardly projecting shoulder 40 which need not be peripherally continuous and which normally underlies the shoulder 26 on the skirt of the inner cap. In turn, the inner surface of the top closing wall 34 of the overcap is provided with dependent spaced driving lugs or teeth 42 cooperating with the lugs 32 on the inner cap and each lug 42 is shaped similarly to-the lugs 32 but in opposite direction, that is, with a vertical abutment surface 420 and relieved trailing surface 42b. Sections at the periphery of the top closing wall 34 of the overcap are weakened as by reducing the cross section thereof for upward bowing or by cutting away narrow arcuate sections to provide slots 44 (FIG. 4) and similarly located sections of the skirt 36 arereduced in thickness, as at 46. This reduced thickness wall section 46 is provided with internal vertically extending ribs or teeth 48 to cooperate with the teeth 25 on the inner cap as will be explained. The reduced wall section 46 is provided with outer vertical finger grip ribs 50.  
 : In the form of the invention shown in FIGS. 6, 7 and 8, the inner cap is the same as that shown in FIGS. 1 to 5 and need not be further described. The outer or overcap 18a is similar to the overcap 18 in its inclusion of a top closing wall 34a with driving lugs 42, a depending skirt36a and weakened wall section 38a terminating in an inward shoulder 40a. The skirt 36a differs in that the cut out slots are omitted and the inner wall surface is provided with a circumferentially continuous array of spaced vertical teeth 54 for cooperation with the teeth 25 on the inner cap and the skirt may thus be squeezed. at any diametrically opposed surface areas and the external surface of the skirt 36a may be knurled or provided with vertical finger grip ribs 56 facilitating:manipulation.  
  The closure of either form is assembled by snapping together the innerwcap and the overcap during which action thei&#39;inward; shoulders 40 of the overcap 18 and 40a of the overcapl8a will spread and then snap back beneath .the shoulders 38, 38a respectively, on the inner caps. This will position the teeth 25 on the inner cap.16 inwardly of the teeth 48 on the outer cap 18 per -mitting relative rotation in a counterclockwise direction of the overcap (FIG. 1). Likewise, the teeth 25 of the inner cap will be spaced inwardly of the teeth 54 of the overcap 18a (FIG. 7). In both forms, with the driving lugs 42 out of vertical lapping, the overcaps will rest essentially in line-contact with the ribs 30 of the inner :caps&#39;althoughthere may be light line contact, with botltleszresting-one upon another in shelf storage or stacked in cases in warehouse storage, between the lower edges of the vertical faces 42a of the driving lugs 42 and the .topof the inner cap, and the upper edges of the vertical faces 32a of the driving lugs 32 with the undersurface of the&#39;overcap, such line contact being provided by the relieved surfaces 32b and 42b of the lugs 32, 42, respectively-Thus, there is little tendency for any frictional setting at these line contacts due to storage or other conditions and substantially all planar surface contact is eliminated.  
  With reference to FIG. 1, an attempt to open the container by rotating the overcap 18 in a counterclockwise direction will result in this cap part rotating relative to the inner cap since the teeth 48 are out of engagement with the teeth 25. This rotation of the overcap will cause the relieved portions 32b and 42b, respectively, to ramp or ratchet over each other. In doing so, the overcap will reciprocate between the positions of FIGS. 1 and 5. Thus the vertical free space between the shoulders 26 and 40 on the&#39;inner and outer caps, respectively, is selected to permit the vertical lapping of the teeth 32, 42 as in FIG. 5 with theshoulder 40 flexed outwardly, as shown, and as the driving teeth or lugs bypass one another, the inherent resiliency of the flexible wall section &#39;38 will cause the shoulder 40 to snap back beneath the shoulder 26 as shown in FIG. 1. Such permissive rotation of the overcap is intended to discourage children from further efforts to open the container. However, an adult will know that radial inward squeezing pressure on the skirt secctions 50 will force the teeth 48 inwardly to engage the teeth 25 and thus permit counterclockwise opening rotation of the inner cap in unison with the overcap for opening the con tainer. Reclosing of the container is accomplished by clockwise rotation of the overcap bringing the vertical surfaces 32a, 42a of the teeth 32, 42, respectively, into driving contact for threading the closure to the container and clamping the sealing disc 22 against the lip of the container. Instead of the cut out sections 44 on the overcap, the top closing wall thereof may be formed of sufficient flexibility to bulge and permit engagement between the teeth 25 and 48 for opening movement of the closure. Operation of the form of closure shown in FIGS. 6, 7 and 8 is essentially the same as described above, except that the skirt 36a of the overcap may be gripped at any diametrical areas for causing engagement between the teeth 54 on the overcap and the teeth 25 on the inner cap. Also, in either form, the top closing wall of the overcap may be given such flexibility as to contribute to the permissive vertical up and down movement of the overcap relative to the inner cap and the thickness of the skirt sections 46 of the overcap 18 may be varied to require greater or less inward pressure to effect interengagement between the teeth 48 and 25 and the flexibility of the skirt 36a of the overcap 18a may be varied for the same purposes.  
  After initial filling, the containers are closed and sealed in automatic capping machines which apply relatively high torque to the overcap resulting in the vertical driving faces 42a of the teeth 42 on the overcap abutting the vertical faces 32a of the teeth 32 on the inner cap and rotating the caps to thread the closure assembly to the container with tight compression of the disc 22 against the lip of the container for hermetically sealing the same. The driving lugs 32 and 42 are constructed to resist any tendency toward stripping thereof under the applied high torque. Thus, the substantially vertical abutment surfaces 32a and 42a tend to prevent any overriding and bypassing of the lugs during the capping machine closing and the relieved surfaces 32b and 42b serve to back up the abutting surfaces and resist any tendency toward stripping. At the same time, the relieved surfaces enter into the permissive counterclockwise rotation of the outer cap as described above. Regardless of the amount of outside loading during automatic capping or warehousing conditions, the cap will function properly on the application thereof to a container and the removal thereof. During capping, the higher the applied force the greater the tendency toward stripping or ratcheting of the driving lugs. However, as the cap assembly gets tighter on the container, the top of the inner cap tends to distort upwardly which the capping machine head tends to keep the top of the overcap down, thus the top portionsare maintained together and the abutting faces of the driving lugs are held in place with little or no tendency to ratchet or pop out of driving position.  
 We claim:  
  1. A safety closure assembly for a container having thread-like formations below the container lip; and comprising an inner cap with a top closing wall to be sealed against the container lip and a depending skirt with external vertical rib means providing teeth and with internal thread-like formations cooperable with the thread-like formations on the container for closing and sealing the container upon rotation in one direction and for opening the container upon rotation in the opposite direction; and an outer cap with a top wall overlying the top wall of the inner cap and a depending skirt encircling the depending skirt of the inner cap and having internal rib means providing teeth normally spaced outwardly from the teeth on the skirt of the inner cap to permit rotation of the outer cap relative to the inner cap in the opening direction of rotation; means trapping the outer cap on the inner cap with permissive relative vertical movement between the top walls of the inner and outer caps; the adjacent enclosed wall surfaces of the inner and outer caps having the major portions thereof spaced apart a certain distance, circumferentially spaced projecting lugs integrally formed on the opposed adjacent enclosed wall surfaces of said inner and outer caps with initially engageable abutment driving surfaces for rotating the caps in unison in the closing direction of rotation initially in automatic capping machines and subsequently by hand after initial opening of the container, and each of said lugs on said inner and outer caps being of substantially the same vertical height as said certain spaced-apart distance of said adjacent enclosed wall surfaces and being relieved from the free edge of the abutment driving surface leaving an edge surface of minimum extent at the adjacent surface of a cap top wall; and the skirt of the outer cap being sufficiently flexible at least at generally diametral areas for finger pressure thereon to shift the teeth of the outer cap inwardly into engagement with the teeth of the inner cap for rotation of both caps in unison in the opening direction and the outer cap being rotatable in the opening direction independently of the inner cap in the absence of sufficient fmger pressure thereon and with the relieved surfaces of the lugs ratcheting over the lugs on the inner cap with the permissive relative vertical shifting of the cap top walls.  
  2. An assembly as claimed in claim 1, wherein opposed peripheral arcuate sections of the top wall of the outer cap are slotted to enhance the flexibility of the subjacent sections of the skirt for finger pressure application and wherein the teeth are carried by said subjacent sections.  
  3. An assembly as claimed in claim 1, wherein opposed peripheral sections of the skirt of the outer cap carry the inwardly projecting teeth and are of reduced cross section to afford flexibility for finger pressure application thereto.  
  4. An assembly as claimed. in claim 1, wheren the trapping means between the inner and outer caps comprises cooperating shoulder means at the free edges of the cap skirts spaced axially apart a distance to assist in the vertical movement of the outer cap and top wall during ratcheting of the lugs as the outer cap is rotated in the opening direction independently of the inner cap.  
  5. An assembly as claimed in claim 4, wherein the cooperating shoulder means includes inwardly projecting shoulders at the free edge of the skirt of the outer cap resiliently maintained in position below shoulder means at the free edge of the skirt on the inner cap.  
  6. An assembly as claimed in claim 5, wherein the skirt of the outer cap is reduced in cross section adjacent the shoulder means for the resilient maintenance thereof in position and permitting outward flexing thereof against the adjacent shoulder means during ratcheting of the lugs.  
  7. An assembly as claimed in claim 1, wherein the teeth on the skirts of the inner and outer caps are disposed substantially completely therearound and wherein the skirt of the outer cap is of substantially uniform flexibility enabling finger pressure application thereto at any diametral areas therearound.  
  8. An assembly as claimed in claim 7, wherein cooperating shoulder means at the free edges of the cap skirts traps together the caps with axial spacing between the shoulder means permitting vertical move ment of the outer cap during ratcheting of the lugs as the outer cap is rotated in the opening direction independently of the inner cap.  
  9. An assembly as claimed in claim 8, wherein the wall of the skirt of the outer cap adjacent the shoulder means thereon is of reduced thickness permitting the shoulder means to be urged outwardly during upward movement of the outer cap on ratcheting of the lugs and to resiliently return to normal position upon downward movement of the outer cap.  
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