CHILD RESISTANT CLOSURES

Abstract: A child resistant closure comprises a threaded closure member (12) and an outer cap member (14) fitted around the closure member. A circumferentially configured radially facing ratchet (28) is provided on the closure member (12) and flexible pawl fingers are provided on the cap member, to allow turning of the closure member in the closing sense only. A socket (38) on the cap member (14) is axially engageable against a bias with a square drive (36) on the closure member to allow turning in either sense. The configuration of the ratchet allows extended linear contact area between the pawl fingers (34) and the working surface (32) of the ratchet even in closures of narrow diameter.

Description: CHILD RESISTANT CLOSURES This invention relates to child resistant closures and in particular, but not exclusively, to child resistant caps for a tube or other container with a narrow threaded opening . It is known to provide child resistant threaded closures for containers, the closure being designed so that it may be tightened by rotating the closure in the tightening sense but that the closure may be undone only by pushing or deforming the cap whilst undoing it. Small children generally do not have the manual dexterity required for the latter compound actions. This type of closure is often used for tablet containers or containers containing harmful liquids such as bleaches, solvent, poisons, etc. For these containers, the neck of the opening is generally relatively wide, typically at least 2cm or so. One example of child resistant closure comprises a single distortable cap element having stops which (when the cap is undistorted) interfere with an associated formation on the neck of the container to prevent the cap being undone. To undo the cap, the cap is distorted to move the stops on the closure and the neck out of registration to allow the closure to be unscrewed. This type of closure has the disadvantages that it requires modification of the neck of the container, and also it requires a squeezing or pincer movement which renders it difficult or impossible for use by those suffering from arthritis or those who are generally f rail . European Published Application No 0725012A1 discloses another type of child resistant cap which comprises an inner internally threaded closure member located within an outer manually grippable ring member. The outer surface of the closure member and the inner surface of the ring member are provided with respective splines, and the ring member and the closure member are relatively moveable axially between a non-drive position and a drive position. The ring member and the closure member are urged towards the non-drive position by a plurality of sprung pawls on the closure member which engage an axially directed ratchet surface on the ring member. The pawls move into and out of engagement m an axial direction to define a ratchet mechanism which allows transmission of torque from the ring member to the closure member m the closing sense only. The pawls therefore serve both to provide an axial bias to urge the closure member and the ring member apart and also as a conventional ratchet mechanism. Although such closures may perform adequately for wide necked bottles or containers, we find that they cannot be suitably adapted for narrow-necked containers because it is not possible to reduce the sizes of the components to match the smaller diameter of a tube whilst still retaining adequate closure characteristics. In attempting to reduce the relevant dimensions we have not found it possible to reduce the diameter of the ratchet mechanism to that suitable for a tube closure whilst still providing sufficiently resilient pawls to transmit the torque required, especially given that the neck of a small tube or other closure may get gummed up in use with stray contents of the tube, thus increasing the torque required. British Patent 1,550,372 discloses a security cap arrangement in which an internally threaded closure element is received in an outer cap element and is capable of limited axial movement. The cap element has an aperture corresponding to a formation on the closure element and the two may be clicked into driving engagement prior to unscrewing the cap. There is no spring bias or ratchet mechanism. British Published Application No. 2 182 648 discloses a child resistant cap comprising two closure element parts biassed to a non-drive position and incorporating a tamper- evident seal . On removal of the seal the outer cap may be depressed to bring respective drive elements into engagement to allow torque to be transmitted from the outer cap to the inner closure element. European Published Application No. 0 519 627 Bl discloses a cap arrangement in which the cap is adapted to co-operate with an annular spanner. Published International Patent Application No. WO97/03914 discloses a closure system including a tool for engaging a child resistant closure. It is an object of this invention to provide a child resistant closure arrangement of the general type in which the closure may be closed by a simple rotation applied to the closure and which is suitable for narrow necked containers such as tubes or the like where the outer diameter of the threaded neck of the container may be of the order of 1.5cm or less. It is however emphasised that the invention also extends to such closures for wide-necked containers of outer diameter of greater than 1.5cm. In one aspect, this invention provides a child resistant closure for a container having an opening, said closure comprising: - a closure member for engagement with said opening; a manually grippable outer member rotatably mounted thereon for rotation about an elongate axis; drive means for transferring rotation between said outer member and said closure member; said drive transfer means comprising a generally cylindrical, radially facing ratchet means associated with one of said outer member and said closure member, said ratchet means comprising at least one working face and at least one camming surface, said drive transfer means further including at least one moveable pawl means associated with the other of said outer member and said closure member, said moveable pawl means being moveable in a generally transverse direction relative to said elongate axis for engaging said ratchet means, whereby rotation of said outer member in a given sense causes at least one pawl means to engage a working face of said ratchet means . In this arrangement, the radially facing generally cylindrical configuration of the ratchet provides ma j or advantages. The linear contact area between the pawl means and the associated working face of the ratchet means is not limited by the diameter of the closure. The contact area may be increased by extending the axial length of the pawl and the working face to suit the flexibility and torque transmission requirements. Thus, the axial extent of the ratchet means may vary from a relatively low proportion of the effective diameter, so that the ratchet means is similar m proportions to a typical toothed gear wheel, to a high proportion where the axial extent may be equal or greater than the effective diameter, to give extended line contact between the pawl means and the working face of the ratchet means to give much greater purchase, without increasing the diameter of the closure. In addition, since the pawl action is transverse to the elongate axis, rather than parallel as m the arrangement of EP 075012 Al, the action of the pawl means is not compromised by any need to accommodate or actively provide axial bias movement. Although either arrangement is possible, it is preferred for the ratchet means to be provided on said closure member, facing radially outwardly, with the or each pawl means being provided on said outer member. Preferably said ratchet means preferably comprises a plurality of working faces disposed generally uniformly about said elongate axis. The ratchet means preferably comprises a respective generally arcuate camming surface between each two working faces. The or each working face is preferably disposed in a generally radial plane with respect to said elongate axis. Preferably, the working face of the or each pawl means is biassed in use to move into and out of engagement with the working face of the ratchet means in a generally radial direction with respect to said elongate axis, and the or each pawl means conveniently comprises a strip of flexible material having sufficient structural flexibility to bias said pawl means into engagement with said ratchet means. Co-operation of the pawl means and the ratchet means will usually provide movement in the closing sense only, with the residual frictional characteristics in the opening sense being insufficient to allow the cap to be undone from a fully closed position. To allow opening, the closure preferably further comprises respective complementary drive means on said closure member and said outer member engageable in use to transmit drive in at least the opening sense, said outer member and said closure member being axially moveable between a drive position in which in use said drive means are brought into engagement and a non-drive position in which said drive means are out of engagement. The arrangement preferably further includes axial bias means. It will be noted in this arrangement that the bias urging the closure member and the outer member apart acts axially, whereas the pawl means are biassed transversely and so may operate substantially independently, allowing each to be optimised for its particular purpose. Preferably the axial bias means comprises elastic distortion means associated with at least one of said outer member and said closure member, elastically distorting at least one of said members on relative axial movement, thereby to provide said bias. The elastic distortion means may conveniently comprise a ramped surface means on one of said members and a co-operating ramp follower means on the other of said members. In a particularly preferred arrangement, said elastic distortion means includes two diametrically opposed rib means on said outer member adapted in use to co-operate with a generally frusto-conical ramp surface provided on said closure member. The respective complementary drive means may conveniently comprise a non-circular male drive portion disposed on one of said members and a correspondingly shaped female drive socket on the other of said members. Thus, the respective complementary drive means may comprise a polygonal drive portion disposed on said closure member and a correspondingly shaped socket on said outer member. To facilitate alignment of the respective complementary drive means when the closure is to be opened, the closure is preferably arranged such that, when a pawl means is in engagement with a working face of said ratchet means, the complementary drive means on said outer member and said closure member are substantially in angular registration. Preferably, said closure element includes an externally accessible drive portion for being engaged in use by a tool or the like to facilitate opening or closure, and the drive portion conveniently pro ects through said outer member. The drive portion preferably comprises an elongate element disposed substantially concentrically with said elongate axis, and the outer member advantageously includes means defining a recess surrounding the exposed region of said drive portion. Preferably a major extent of said drive portion is of generally constant polygonal cross-section, and the free end of said drive portion is sharpened or spiked, thereby m use to facilitate penetration and rupture of a foil or membrane associated with the opening of the container. The invention also extends to a child resistant closure as defined above in combination with a tool having complementary engagement means for dπveably engaging m use the drive portion of said closure member. The tool conveniently includes attachment means to allow it to be attached to a structure. In another aspect, this invention provides a child resistant closure for a container having an opening, said closure comprising a closure member for engagement with said opening, a manually grippable outer member rotatably mounted thereon, and drive transfer means disposed therebetween, such that the closure may be closed by a simple rotation applied to the outer member, but that opening of the cap requires axial movement of the outer member relative to said closure member, as well as rotation, wherein said drive transfer means includes respective engagement means arranged radially intermediate said closure member and said outer member, one of said engagement means comprising a generally cylindrical, radially facing ratchet means associated with one of said closure member and said outer member, and the other engagement means comprising a movable pawl means associated with the other of said closure member and said outer member and moveable in use towards said ratchet means. In a further aspect, the invention provides a child resistant closure for engagement with an opening, said closure comprising a closure element and a manually grippable outer member mounted on said closure element, said closure element and said outer member having first respective complementary drive elements engageable to transmit rotation to said closure element in the closing sense only, and second respective complementary drive elements engageable to transmit drive in at least the opening sense, wherein axial movement of the outer member relative to said closure element is required to engage said second complementary drive elements, the closure further including bias means urging said second complementary drive elements out of engagement. The bias may be provided by elastic deformation of at least one of said closure element and said outer member. In a preferred arrangement, one or more abutments on one of the closure element and the outer member are operable to engage a tapered surface on the other of said member and said element, whereby relative axial movement in one direction is accompanied by elastic distortion. In a particularly preferred embodiment, the closure element has an outer tapered surface engageable by a plurality of abutment means on said outer member. The first complementary drive elements preferably comprise ratchet surface means provided on one of the closure element and the outer member, and resiliently deformable pawl finger means on the other of said member and said element to provide a ratchet effect, the pawl finger means being disposed generally transversely. By this arrangement, the ratchet effect is provided radially intermediate the closure element and the outer member rather than axially with respect thereto as on the known child resistant closures described above. This gives the opportunity to provide a reasonable moment arm and also extended line contact between the ratchet fingers and the cam surface means to allow transmission of significant tightening forces. Said second complementary drive elements preferably comprise complementary male and female parts axially engageable with each other to transmit drive therebetween. The closure element preferably includes a post or spike projecting through said outer member, optionally in a recess, the post or spike being available to rupture a foil or membrane associated with the container opening. In a further aspect, this invention provides a child resistant closure for engagement with an opening, said closure comprising a closure member and a manually grippable outer member mounted on the closure member and drive transmission means between the closure member and the outer member for transmitting the drive from the outer member to the closure member for opening and closing the said closure member, said closure member further having an externally accessible drive spigot for engagement by a tool or the like, said spigot being sharpened or spiked, thereby in use to facilitate penetration and rupture of a foil or membrane associated with the opening. In yet a further aspect, this invention provides a child resistant closure for engagement with an opening, said closure comprising a closure member and a manually grippable outer member mounted on the closure member and drive transmission means between the closure member and the outer member, said drive transmission means comprising ratchet means provided on a radially outwardly facing surface of the closure member and pawl means provided on a radially inwardly facing surface of said outer member. The pawl means preferably comprise one or more resilient tongues extending inwardly from the inner wall of the outer member. Whilst the invention has been described above, it extends to any inventive combination of features set out above or in the following description. The invention may be performed in various ways, and two embodiments thereof will now be described by way of example only, reference being made to the accompanying drawings in which : - Figure 1 is an exploded view of a first embodiment of a child resistant cap for a tube, with the outer cap shown in cross-section; Figure 2 is a top plan view of the closure element of the closure of Figure 1; Figure 3 is an under plan view of the outer cap of the closure of Figure 1; Figure 4 is a side cross-section of the closure element and outer cap, when assembled; Figure 5 is a sketch of a general perspective view of the closure element; Figure 6 is a schematic view of a spanner for use with the enclosure of Figures 1 to 5; Figure 7 is an exploded view of a second embodiment of child resistant cap for a tube, with the outer cap shown in cross-section; Figure 8 is a top plan view of the closure element of the closure of Figure 7; Figure 9 is a side view of the outer cap of the closure of Figure 7 ; Figure 10 is an under plan view of the outer cap of the closure of Figure 7; Figure 11 is a section view taken in lines XI -XI of Figure 10; Figure 12 is a side cross-section view of the closure element and outer cap and seen when assembled, to show the fit and angular registration of the parts. Referring initially to the first embodiment, in Figure 1 the closure 10 comprises a closure element 12 and an outer cap 14 snap fitted together, both being moulded from plastics material. The closure element 12 comprises a base 16 defining an internally threaded bore 18 for threadedly engaging the opening 20 of a tube 22. The lower portion of the base 16 is provided with a tapered skirt 24 which cooperates with pips 26 on the inside of the outer cap 14, to be described below. Above the skirt 24 is a circumferentially configured, radially facing ratchet 28 whose shape is apparent from Figure 2, comprising convex camming portions 30 and working faces 32. The ratchet 28 co-operates with pawl fingers 34 (see Figure 3) integrally formed with the outer cap 14 to allow torque to be transmitted from the outer cap to the closure element 12 in the clockwise (closing) sense only. From Figures 1 and 3 it will be seen that the pawl fingers 38 are generally rectangular strips, with the upper and radially outer edges thereof merging with the inner upper and cylindrical walls of the cap. Thus as seen, the pawl fingers 24 extend down from the top wall of the cap, thus facilitating moulding of the cap. Above the ratchet 28 is a square drive portion 36 onto which a square socket 38 in the central portion of the outer cap may be slid axially to allow drive to be transmitted to the closure element in either sense. A post 40 of square cross-section slightly less than that of the drive portion 36 extends upwardly and terminates with a spike 42. The outer cap 14 has an internal lip 44 which forms an interference fit with the widest portion of the skirt 24 to retain the closure element within the outer cap in a snap fit. Referring now to Figure 4, in the equilibrium position of the closure, the pips 26 co-operate with the skirt 24 to hold the socket 38 just clear of the drive portion 36 so that these elements (herein referred to as "second complementary drive elements") are not engaged. However the pawl fingers 34 are in contact with the ratchet 28 and so these elements (herein referred to as "first complementary drive elements") are engaged, but owing to the ratchet configuration, significant torque can be transmitted from the outer cap 14 to the closure element 16 only in the clockwise (closing) sense. To undo the closure, the outer cap 14 is pressed downwardly relative to the closure element so that the pips 26 ride over the skirt 24 to distort the cap and provide an axial spring bias, and the socket 38 moves over the drive portion 26 (assuming they are correctly angularly aligned) . Torque may then be transmitted from the outer cap 14 to the closure element 16 in the opening sense. To assist proper alignment of the socket 38 in the drive portion 36, the ratchet 28 and the panel fingers 34 are preferably angularly disposed such that when the pawl fingers 34 are in contact with the working face 32 of the ratchet 32, the drive portion 36 and socket 38 are in angular registration. The outer cap 14 has a central recess 46 into which the spike 42 projects. The recess 46 is dimensioned to fit with clearance around the threaded opening 20 of the tube and the spike 42 located to pierce any safety or security membrane or foil over the opening 20. Referring now to Figure 6, there is shown a spanner 48 having a socket 50 externally of dimension to fit into the recess of the outer cap and having an internal bore 52 shaped complementarily to match the upper portion of the post 40 and spike 42. Since the post and spike are an integral part of the closure element 16, the closure may be undone by fitting the spanner of Figure 6 over the spike and rotating the spanner in the appropriate direction. The spanner has two holes 54 in it to allow it to be secured to a work surface or other structure so that a user with a poor grip can engage the spanner with the recess and spike and turn the tube in the appropriate sense. Referring now to Figures 7 to 13, the second embodiment is a close variant of the first embodiment with the components closely similar and operating on the same or similar principles. The closure 110 comprises a closure element 112 and an outer cap 114 snap fitted together, both moulded from plastics material. The closure element 112 comprises a base 116 defining an internally threaded bore 118 for threadedly engaging the opening 120 of a tube 122. The lower portion of the base 116 is provided with a tapered skirt 124 which co-operates with two diametrically opposed ribs 126 on the inside of the outer cap 114 (see Figures 10-12) , to be described below. Above the skirt 124 is a circumferentially configured, radially facing ratchet 128 whose shape is apparent from Figure 8, comprising convex camming portions 130 and working faces 132. The ratchet 128 co-operates with pawl fingers 134 (see Figure 10) integrally formed with the outer cap 114 to allow torque to be transmitted from the outer cap 114 to the closure element 112 in the clockwise (closing) sense only. Inspection of Figures 10 and 11 shows that, as in the previous embodiment, the upper and radially outer edges of the pawl fingers 134 merge with the associated inner surfaces of the walls of the cap 114. Above the ratchet 128 is a square drive portion 136 onto which a square socket 138 in the central portion of the outer cap 114 may be slid axially to allow drive to be transmitted to the closure element 112 in either sense. A post 140 of square cross-section slightly less than that of the drive portion 136 extends upwardly and terminates with a spike 142. The outer cap 114 has an internal lip 144 which forms a snap fit with the widest portion of the skirt 124 to retain the closure element within the outer cap. Referring now to Figures 12 and 13, in the equilibrium position of the closure, the ribs 126 co-operate with the skirt 124 to hold the socket 38 just clear of the drive portion 136 so that these elements are not engaged. However, as seen in Figure 13, the pawl fingers 134 are in contact with the ratchet 128 and so these elements are engaged, but owing to the ratchet configuration, significant torque can be transmitted from the outer cap 114 to the closure element 116 only in the clockwise (closing) sense. To undo the closure, the outer cap 114 is pressed downwardly relative to the closure element so that the ribs 126 ride over the skirt 124 to distort the cap 114 and provide an axial spring bias, and the socket 138 moves over the drive portion 136 (assuming they are correctly angularly aligned) . Torque may then be transmitted from the outer cap 14 to the closure element 116 in the opening sense. To assist proper alignment of the socket 138 in the drive portion 136, the ratchet 128 and the panel fingers 134 are preferably angularly disposed such that when the pawl fingers 134 are in contact with the working face 132 of the ratchet 128, the drive portion 136 and socket 138 are in angular registration. The outer cap 114 has a central recess 146 into which the spike 142 projects. The recess 146 is dimensioned to fit with clearance around the threaded opening 120 of the tube and the spike 142 located to pierce any safety or security membrane or foil over the opening 120. Both embodiments are intended to be produced by moulding a plastics material although the invention is not so limited. It should be noted that various modifications are possible to the embodiments described herein without departing from the invention. For example whilst in the illustrated embodiments the ratchet means is provided on the closure element and the pawl fingers are provided on the cap, this arrangement could be reversed. Also, the closure may be used for non-threaded closures.

Claims: CLAIMS 1. A child resistant closure for a container having an opening, said closure comprising: - a closure member for engagement with said opening; a manually grippable outer member rotatably mounted thereon for rotation about an elongate axis; drive means for transferring rotation between said outer member and said closure member, said drive transfer means comprising a generally cylindrical, radially facing ratchet means associated with one of said outer member and said closure member, said ratchet means comprising at least one working face and at least one camming surface, said drive means further including at least one moveable pawl means associated with the other of said outer member and said closure member, said moveable pawl means being moveable in a generally transverse direction relative to said elongate axis for engaging said ratchet means, whereby rotation of said outer member in a given sense causes at least one pawl means to engage a working face of said ratchet means. 2. A child resistant closure according to Claim 1, wherein said ratchet means is provided on said closure member, facing radially outwardly, and the or each pawl means is provided on said outer member. 3. A child resistant closure according to Claim 1 or Claim 2, wherein said ratchet means comprises a plurality of working faces disposed generally uniformly about said elongate axis. 4. A child resistant closure according to Claim 3, wherein said ratchet means comprises a respective generally arcuate camming surface between each two working faces. 5. A child resistant closure according to any of the preceding Claims, wherein the or each working face is disposed in a generally radial plane with respect to said elongate axis. 6. A child resistant closure according to any preceding Claim, wherein the working face of the or each pawl means is biassed in use to move into and out of engagement with the working face of the ratchet means in a generally radial direction with respect to said elongate axis. 7. A child resistant closure according to Claim 6, wherein the or each pawl means comprises a strip of flexible material having sufficient structural flexibility to bias said pawl means into engagement with said ratchet means. 8. A child resistant closure according to any preceding Claim, wherein said drive transfer means further comprises respective complementary drive means on said closure member and said outer member engageable in use to transmit drive in at least the opening sense, and wherein said outer member and said closure member are axially moveable in use between a drive position in which said drive means are brought into engagement and a non-drive position in which said drive means are out of engagement . 9. A child resistant closure according to Claim 8, including bias means for urging said outer member and said closure member toward said non-drive position. 10. A child resistant closure according to Claim 9, wherein said bias means comprises elastic distortion means associated with at least one of said outer member and said closure member, elastically distorting at least one of said members on relative axial movement in use, thereby to provide said bias. 11. A child resistant closure according to Claim 10, wherein said elastic distortion means comprises a ramped surface means on one of said members and a co-operating ramp follower means on the other of said members. 12. A child resistant closure according to Claim 11, wherein said elastic distortion means includes two diametrically opposed rib means on said outer member adapted in use to co-operate with a generally frusto-conical ramp surface provided on said closure member. 13. A child resistant closure according to any of Claims 8 to 12, wherein said respective complementary drive means comprises a non-circular male drive portion disposed on one of said members and a correspondingly shaped female drive socket on the other of said members. 14. A child resistant closure according to Claim 13, wherein said respective complementary drive means comprises a polygonal drive portion disposed on said closure member and a correspondingly shaped socket on said outer member. 15. A child resistant closure according to any of Claims 8 to 14 adapted such that in use, when a pawl means is in engagement with a working face of said ratchet means, the complementary drive means on said outer member and said closure member are substantially in angular registration. 16. A child resistant closure according to any of the preceding Claims, wherein said closure element includes an externally accessible drive portion for being engaged in use by a tool or the like to facilitate opening or closure. 17. A child resistant closure according to Claim 16, wherein said drive portion projects through said outer member. 18. A child resistant closure according to Claim 16, wherein said drive portion comprises an elongate element disposed substantially concentrically with said elongate axis . 19. A child resistant closure according to Claim 17 or 18, wherein said outer member includes means defining a recess surrounding the exposed region of said drive portion. 20. A child resistant closure according to any of Claims 16 to 19, wherein a major extent of said drive portion is of generally constant polygonal cross-section. 21. A child resistant closure according to any of Claims 16 to 20, wherein the free end of said drive portion is sharpened or spiked, thereby in use to facilitate penetration and rupture of a foil or membrane associated with the opening of the container. 22. A child resistant closure system comprising a child resistant closure in accordance with any one of Claims 16 to 21, in combination with a tool having complementary engagement means for driveably engaging in use the drive portion of said closure member. 23. A child resistant closure system according to Claim 23, wherein said tool includes attachment means to allow it to be attached to a structure. 24. A child resistant closure for engagement with an opening, said closure comprising a closure member and a manually grippable outer member mounted on the closure member and drive transmission means between the closure member and the outer member for transmitting the drive from the outer member to the closure member for opening and closing the said closure member, said closure member further having an externally accessible drive spigot for engagement by a tool or the like, said spigot being sharpened or spiked, thereby in use to facilitate penetration and rupture of a foil or membrane associated with the opening. 25. A child resistant closure for engagement with an opening, said closure comprising a closure member and a manually grippable outer member mounted on the closure member and drive transmission means between the closure member and the outer member, said drive transmission means comprising ratchet means provided on a radially outwardly facing surface of the closure member and pawl means provided on a radially inwardly facing surface of said outer member. 26. A child resistant closure according to claim 25, wherein said pawl means comprises one or more resilient tongues extending inwardly from the inner wall of the outer member . 27. A container with a child resistant closure in accordance with any one of claims 1 to 21 and 24 to 26.

Inventors: DODGE LEYTON STUART, DODGE, LEYTON, STUART
Applicants: DODGE LEYTON STUART, HSD CAPITALL MOULDING LIMITED, DODGE, LEYTON, STUART
Application year: 1998
Main classification: B65D50
IPC codes: B65D50