WO2005008133A1

WO2005008133A1 - Child resistant actuation mechanism for gas lighters and other devices

Info

Publication number: WO2005008133A1
Application number: PCT/IB2004/002477
Authority: WO
Inventors: Carel Sewalt
Original assignee: Swedish Match Lighters B.V.
Priority date: 2003-07-16
Filing date: 2004-07-16
Publication date: 2005-01-27
Also published as: GB2404723B; GB0316661D0; WO2005008134A1; GB2404723A; GB0416652D0; US20080050686A1

Abstract

A child resistant actuation mechanism comprises a flexible actuation surface (20, 31, 91, 220) which is depressible by the user to couple an actuating force via a body of volumetrically displaceable material, such as a gel (36), to an operable internal component. The operable component may be an ignition (82) or fuel release (10, 42, 45) mechanism in a gas lighter, or an enabling (100, 102, 105, 240, 250) or disabling (50, 61, 70, 113, 117, 230) device which interacts with another operable mechanism. The operation of the actuation means may also be enabled or disabled by another operable mechanism or by a trigger or safety button (7, 8). The user may be required to apply a minimum force over a minimum surface area so as to achieve a minimum volumetric displacement of the gel in order to operate the operable component. The invention may be applied to any user operable device such as safety gates and buckles as well as to gas lighters.

Description

Child resistant actuation mechanism for gas lighters and other devices

This invention relates to child resistant actuation mechanisms for gas lighters and other devices.

It is often desirable to make it difficult for small children to actuate devices, by which is meant any article which includes at least one working component which is operable by a user. Examples include staplers and other small household objects, latches and the like, such as for child safety gates or cupboard doors, buckles for pushchairs, and numerous other mechanical devices.

Electromechanical devices include DIY tools such as drills, remote control switch units, such as for stairlifts or garage doors, and any other object having a mechanically operated switch with which a child may come into contact.

Gas lighters are a particularly good example and will be used to illustrate the present invention, although it is by no means limited thereto. These well known devices consist essentially of a small pressurized fuel gas container or reservoir, a valve which is operable (conveniently by means of a lever) to allow fuel to escape, and means, such as a piezoelectric device or a sparkwheel cooperating with a flint, for generating a spark to ignite the gas. Common types of gas lighters include small cigarette lighters for carrying in the pocket, and larger utility lighters which are equipped with an elongate nozzle and are typically used for igniting burners on gas cookers, lighting barbecues and camp fires and the like.

It is well known that children are liable to play with objects such as lighters, and serious accidents can occur as a result. Lighters must therefore be designed to minimize the chance of a child being able to light them. In other words, they should be child-resistant, though perfect child-proofing is of course impossible. Ideally, an adult should be able to use the lighter easily and a child should find it impossibly difficult to use. But in practice this obviously cannot be achieved, and a lighter is regarded as child-resistant if it provides a balance between these two conflicting requirements which is as good as is reasonably feasible and which fulfils minimum child resistance criteria.

A minimum standard for child resistance in lighters has been specified in the USA by means of a functional test by the Consumer Product Safety Commission: 16 CFR Parts 1145 and 1210, Risks of Injury Associated with Lighters That Can Be Operated by Children; Safety Standard for Cigarette Lighters; Rules: Federal Register, Monday July 12 1993. The degree to which a lighter is child resistant may be objectively determined by applying the test described in these Rules and Regulations.

Piezoelectric gas lighters, which is to say, gas lighters which are equipped with piezoelectric spark generators, typically include an operating button in the form of a pushbutton or trigger which is depressed by the user to generate a spark and/or to open the valve. A cooperating safety button may be provided, so that both the operating button and the safety button must be operated together or in sequence in order to produce a flame. Gas lighters with flint ignition may similarly be provided with an operating button or a sliding cap which must be depressed or pivoted in order to draw a serrated friction element across the flint and so produce a sheaf of sparks. Alternatively, so called "roll-and-press" lighters are provided with a wheel assembly which the user's thumb rotates to produce sparks before falling onto a pushbutton forming part of the valve lever, so releasing fuel which is ignited by the sparks.

In early child resistant lighters, a catch mechanism was arranged to block the movement of the operating button or the valve lever unless the user first moved the catch to the enabled position. In later variants, such as US 6,102,689 to Man for a roll-and-press lighter, the catch was arranged to return automatically to the disabled position after operation of the lighter. However, where a safety catch can be left in the unblocking condition by an adult user, a child could subsequently operate the lighter. It is preferred therefore to provide a safety catch or safety button which remains in the blocking condition at all times unless operated by the user, so that the safety catch or safety button must be operated substantially at the same time as the operating button.

By providing an operating button and a safety button, two or more consecutive movements may be required substantially simultaneously to operate the lighter. For example, our earlier published PCT patent application, WO 01/51855 discloses a utility lighter wherein the safety button is located away from the trigger on the top of the lighter body so as to be inoperable by a child using one hand. The safety button must be depressed forwardly and downwardly in order to unblock the trigger, and returns automatically to the blocking position when released, adding a further level of difficulty for children.

Although devices operating generally on this "blocking" principle may be effective in preventing children from operating a lighter, the application of excessive force to the child resistant blocking mechanism could damage it and leave the lighter vulnerable to unintended use. In order to overcome this problem, an alternative "enabling" approach has recently emerged, in which an operable mechanism of the lighter is arranged to be selectively disabled from operating the lighter without its movement being blocked. The adult user must then enable the mechanism in addition to operating it in order to operate the lighter.

US 6,287,109 to Hirota & Co. Ltd. discloses a piezoelectric cigarette lighter which exemplifies the latter "enablement" approach. In the disabled condition, a slider piece mounted in a button on the top of the lighter may be depressed by the user without either producing a spark or releasing fuel. In order to ignite the lighter, the user must first slide the slider piece forwards towards the burner. This aligns a downwardly extending abutment on the slider piece with a corresponding abutment on a latch element which in turn operates the spark generator and the fuel release lever. The slider piece and button may then be depressed to operate the fuel lever and the spark generator and so produce a flame.

US 6,336,807 to Hsu discloses a utility lighter having a pair of sprung rods slidably mounted in a pivotable frame. The frame is pivoted by means of a separate safety lever on the side of the lighter casing to move the rods into alignment respectively with the fuel lever and the spark generator, so that when the trigger is depressed it presses against both of the rods to actuate the fuel lever and the spark generator and so produce a flame. In the disabled condition, the rods are misaligned so that the trigger may be depressed without producing a spark.

While both the "blocking" and "enablement" approaches may prevent ignition by children, it remains possible especially with simpler lighters of this type that children may eventually achieve ignition by playing with the operating and safety buttons for an extended period. Some lighters therefore adopt an alternative approach by adjusting the amount of force required to operate the lighter so as to be readily achievable by adults but not by children.

An example of this approach is JP 2002048341 A to Tokai Corp., in which a roll- and-press lighter is provided with a strong spring underneath the lever. The user must press down hard enough to depress the lever against the enhanced spring force.

In a similar approach, the child may be distinguished from the adult user by the amount of pulp on the ball of the user's thumb. For example, US 6,095,796 to Sung discloses a piezoelectric lighter wherein an operating button is inset into a safety button. The operating button must be depressed below the top of the safety button in order to ignite the lighter, which is achievable by an adult but not by a child due to the greater amount of pulp on the adult's digit. While the latter two lighters will distinguish between the child and the adult user, the possibility remains that a child may be able to ignite them by unforeseen means. For example, the child may attempt to ignite the Tokai lighter by rolling it against furniture or along the floor. Similarly, the child may attempt to insert the tip of its finger or even a small object into the aperture in the safety button of the Sung lighter, so as to depress the operating button.

The need therefore remains for a reliable mechanism for preventing the operation by children of lighters as well as other devices such as electric tools, remote controls, locks, and numerous other mechanical and electromechanical devices which could cause damage or injury to the child or others if inadvertently actuated.

It is the object of the present invention to provide an actuation means for lighters and other devices which is readily operable by an adult user yet reliably prevents operation by children under five years of age.

According to the present invention there is provided a child resistant actuation means for a device, the device having at least one operable component;

characterised in that the actuation means comprises a volumetrically displaceable material together with an actuation surface accessible by a user of the device, wherein the operable component is operatively coupled to the actuation surface by the material such that the operable component is operable by the application by the user of an actuating force to the actuation surface.

Preferably the displaceable material is a gel and the actuation surface comprises a flexible membrane forming part of the outer surface of the device which is gripped by the user during operation. The component may be operable by the application of a predetermined minimum actuating force and/or by the displacement of a predetermined minimum volume of the gel. Preferably the user must apply the actuating force over at least a minimum surface area of the membrane, which conveniently is arranged to correspond to the surface area which may be engaged in normal use of the device by one hand of an adult user.

When a small child applies a force to a surface, the characteristics of its interaction with the surface may be distinguished from those of an adult in several key respects. The overall size of its hand and the length of its fingers, and hence the surface area that it can cover, will typically be much smaller than those of an average adult. The amount of pulp on its digits and palm will be less than that of an adult, as will the strength of its grip and the force that it can apply with its fingers. Many other specific characteristics are similarly distinctive.

There is of course considerable variation within both the adult and the child population; for example, many adults suffer from arthritis and other conditions which may reduce the amount of force that they are able to apply with their hands. By operatively coupling the actuation surface to the component by means of a gel or similar material, the invention makes it possible to select the operating characteristics of the device so as to distinguish more reliably between the child and the adult user by means of all of these distinguishing characteristics, separately or in combination, while still ensuring that the device is readily operable by adults.

The operable component may be operatively coupled to the actuation surface indirectly, for example via an intermediate mechanism or enabling device interposed between the gel and the operable component. The user may then be required to operate a separate safety button or a trigger to enable the intermediate mechanism so that the actuation force is transmitted from the actuation surface to the operable component. Similarly, a disabling or blocking device may be interposed for disabling the operation of the operable component unless the disabling device is first placed in an enabling condition by operation of a separate safety button. Alternatively, the operable component may itself comprise an enabling or disabling device for respectively decoupling or disabling the action of a separate trigger or safety button which in turn is operable by the user to actuate an operable mechanism of the device.

Means may also be employed to determine the parameters within which the user may interact with the actuation surface. For example, a lighter may include one or more operating buttons or safety buttons located away from the actuation surface, so that a child cannot grip the surface with both hands and at the same time operate the buttons. The actuation surface may be arranged within a protective frame, so that it cannot be operated by pressing against a hard surface, but only by pressure by a deformable surface such as the pulp of the user's palm and digits. The actuation surface may also be arranged to conform to a three dimensional profile, so that it cannot be actuated by pressure against a flat object or even an internal corner of an object, but only by gripping the device substantially all the way around its body.

In this specification:

"Operable mechanism" means any component or components of the device which can be operated, directly or indirectly, by the user. In gas lighters, operable mechanisms include fuel release valves, parts thereof and associated components, ignition means, parts thereof and associated components, blocking devices, enabling devices, disabling devices and operating elements.

"Operable component" means an operable mechanism which can be operated by the application by the user of an actuating force to the actuation surface. "Disabling device" or "disabling mechanism" means an operable mechanism which is effective, directly or indirectly to prevent the operation of another operable mechanism.

"Blocking device" or "blocking mechanism" means a disabling device which is effective to mechanically impede the operation of another operable mechanism.

"Enabling device" or "enabling mechanism" means an operable mechanism which is effective, directly or indirectly to operatively couple or decouple one operable mechanism to or from another operable mechanism. The operable mechanisms may include in particular operating elements or operable components.

"Operating element" means an operable mechanism which is accessible for direct actuation by the user. In this specification the terms "trigger" and "button" are synonymous with "operating element".

Further advantages and features of the invention will become apparent from the following description and the accompanying drawings, in which various embodiments are described solely by way of illustration and without any limitation to the scope of the invention. Referring to the drawings:

Fig. 1A is a side view of a first lighter with a gel capsule in a protective frame forming an actuation surface;

Fig. IB shows the first lighter in use;

Fig. IC shows the first lighter with the protective frame and gel capsule removed;

Fig. ID is a plan view of the first lighter corresponding to Fig. IC;

Fig. 2 shows the protective frame of the first lighter; Fig. 3 A is a side view of the gel capsule of the first lighter;

Fig. 3B is a cross section through line X - X of Fig. 3 A;

Fig. 3 C is an end view of the gel capsule of Fig. 3 A;

Fig. 4 A shows a first alternative operable component of the first lighter in the rest position;

Fig. 4B shows the operable component of Fig. 4A in the operated position;

Figs. 5A and 5B show a second alternative operable component in respectively the rest and operated positions;

Figs. 6 and 7 show respectively third and fourth alternative operable components in the rest position;

Fig. 8 A is a side view of a second lighter with a flexible handgrip forming an actuation surface;

Fig. 8B shows the second lighter with the flexible handgrip removed;

Fig. 8C is an end view of the inner handle of the second lighter with the handgrip removed;

Fig. 8D is a longitudinal section through the inner handle of the second lighter showing a first alternative embodiment;

Fig. 8E is a view corresponding to Fig. 8D in a second alternative embodiment; Fig. 9 is a longitudinal section through the flexible handgrip of the second lighter;

Fig. 10 shows a partial internal view of a third lighter, with the trigger shown in longitudinal section;

Fig. 11 shows a similar view of a fourth lighter;

Fig. 12 shows a development of the third lighter;

Fig. 13 is a side view of the first lighter, partially cut away to show a development of the operable component of Figs. 4A and 4B;

Fig. 14 shows a disabling mechanism cooperating with the actuation means;

Fig. 15 shows a fifth lighter with a gel capsule retained in a protective frame to form an actuation surface;

Fig. 16 shows the fifth lighter with the lighter casing and gel capsule cut away to show a first alternative operable component;

Fig. 17 shows the gel capsule of the fifth lighter;

Fig. 18 shows the fifth lighter with the lighter casing and gel capsule cut away to show a second alternative operable component; and

Fig. 19 shows the fifth lighter with the lighter casing cut away to show a third alternative operable component.

Corresponding reference numerals are used for corresponding parts throughout. Referring to Figs. 1 A - ID, a first utility lighter comprises a lighter body 1 supporting a nozzle 2 at one end and a handle section 3 at the other. A fuel reservoir is arranged within the body together with various operable mechanisms, including a piezoelectric ignition unit and a fuel release valve operated by a lever. A trigger 7 is arranged on the lower surface of the lighter body and a safety button 8 on the upper surface. The handle comprises a generally cylindrical inner handle 4 with a collar 5 at one end and a series of small locating holes 6 at the other. An upper section of the inner handle is cut away to accommodate a lever 10.

Referring also to Figs. 2 and 3 A - 3C, the handle section is provided with an actuation surface formed by a gel capsule 30 and a protective frame 20. The capsule comprises a double walled tube of deformable elastomeric material with three textured grip pads 31 moulded on the outer surface of its outer wall 32, which thus forms a flexible membrane. The outer wall 32 and inner wall 33 are joined at both ends 34 to define a through bore 35 and an annular space between the two walls which is filled with a gel 36. Alternatively any other suitable volumetrically displaceable fluid might be used.

The protective frame 20 is formed from plastics material and comprises a generally tubular structure with an end wall 21, an opposite open end 22 and three cutouts 23. Internal ribs 24 are formed adjacent the end wall and have locking projections 25 on their inner faces. A circular wall 26 is formed around the inner surface of the frame. Preferably the side wall 27 of the frame is resiliently depressible.

The capsule is filled with gel before it is sealed and then slid over the inner handle 4 so that the inner handle passes through the bore 35 and is gripped snugly by the inner wall 33. The capsule is positioned so that the three grip pads 31 lie respectively on the bottom and sides of the handle as shown in Fig. 1 A, and the protective frame is then slid over the capsule and inner handle until the grip pads are aligned with the cutouts. The open end 22 of the frame is secured to the collar 5 and the locking projections 25 engage in the locating holes 6 in the inner handle, locking the frame securely in place on the handle. In this position the frame is spaced apart from the handle and supported at its rear end by the internal ribs 24, and the capsule 30 is trapped axially between the lighter body next to the collar 5 at one end and the wall 26 at the other, so that it is held securely in position with the grip pads protruding slighly through the cutouts as shown.

When the user grasps the lighter, his thumb falls naturally onto the safety button 8 with his index finger on the trigger 7, and the palm and the remaining three fingers embrace the actuation surface which comprises the grip pads 31 together with the depressible side wall of the frame 20. It will be seen from Fig. IB that in this position all or most of the surface area of the bottom and right side grip pads 31 is covered by the user's hand while about 60 percent of the surface area of the left side grip pad, which is visible in the drawing, is covered. When the user applies an actuating force by squeezing the handle, the grip pads 31 as well as the resilient frame are compressed. Since the gel is confined between the inner handle and the surrounding frame, it is displaced by the pressure and tends to bulge out in the areas of the pads which are not covered by the user's hand. It also presses inwardly against the inner wall 33 of the capsule so as to operatively couple the actuation surface to the lever 10 by transmitting the actuating force to depress the lever into the inner handle. The lever in turn may be arranged to transmit the actuating force to another operable component of the lighter as further explained below. The degree of depression of the lever which results from the user gripping the handle can be carefully controlled by adjusting various parameters, including inter alia the stiffness of the frame, the size and shape of the cutouts, the quantity and viscosity of the gel, the overall shape and surface area of the actuation surface, the thickness and flexibility of the capsule walls, the shape and surface area of the lever 10 and the magnitude of any restoring force acting on the operable component. Separate biasing means may also be provided for biasing the lever or other operable component to the rest position so as to resist the actuating force, and these too will be adjustable to control the degree of depression of the lever.

By accurately controlling the degree of depression of the lever which results respectively from an adult or a child grasping and squeezing the lighter handle, the operating characteristics of the lighter can be selected so as to ensure that operation of the lighter is easily achievable by adults while being as difficult as possible for children.

For example, the lighter may be configured so that it is operable only when the user applies an actuating force to at least a minimum surface area of the membrane. A child's characteristically smaller hands will be unable to cover as much of the surface area of the grip pads and the resilient frame as those of an adult, so that when it squeezes the handle the gel will bulge out in the uncovered areas, relieving the pressure and avoiding depression of the lever.

The lever or other operable component may also be arranged so that in order to operate it the user must apply at least a minimum actuating force to the actuation surface. Where separate biasing means are provided for restoring the operable component to the rest position, the minimum actuating force may also be adjusted by adjusting the biasing means.

The lighter may also be arranged so that in order to operate the operable component the user must apply an actuating force to the actuation surface so as to displace at least a minimum volume of gel. Thus for instance when a child compresses the handle, its hand will apply insufficient force to displace the minimum volume necessary to depress the lever through the required distance, and the smaller size of its hand will be insufficient to confine the gel, allowing the applied actuating force to be dissipated by displacement of the gel by bulging of the free area of the membrane outwardly through the cutouts and between and around the child's fingers. In practice all of these parameters may be controlled and adjusted together by means of empirical tests to produce an optimum combination of child resistancy and ease of use. The requirement for the simultaneous application of at least a minimum actuating force and at least a minimum volumetric displacement is particularly difficult for a small child to understand, so that even by observing the repeated operation of the lighter by an adult, a small child will find it difficult or impossible to understand the key requirements for successful operation. The lighter thus provides a significant intellectual barrier to operation by children as well as a physical impediment.

Desirably, the actuating surface is arranged as shown so that it covers the curved surface of the lighter handle around most or all of its circumference. This makes it virtually impossible for a child to apply an actuating force by pressing the handle against a floor or furniture.

The lighter illustrated includes a trigger 7 and a safety button 8. Neither of these components is essential, and in its simplest form the lighter may be operated merely by compression of the actuation surface, which is arranged to directly operate the fuel release lever and ignition mechanism. Desirably however, by constraining the user to operate one or both of these operating elements at the same time as compressing the handle, it is made much more difficult for a child to apply the required actuating force by for example squeezing the handle with both hands. More than two operating elements may be provided.

The buttons may be arranged so that they are operable by different fingers of the same adult hand, but too far apart for a child to operate with one hand. They may also be arranged so that more than one movement is required - for example, the safety button 8 may be arranged so that it has to be slid forwards towards the nozzle and then depressed in order to release or enable the trigger or the gel actuation means. This makes it even more difficult for a child to operate one or both of the buttons by unconventional means while applying an adequate actuating force to the actuation surface.

It will be understood from the foregoing that the actuation means may be arranged so as to directly operate either or both of the ignition means and the fuel release valve, or alternatively to operate any other operable mechanism of the lighter. This might be for example a disabling or blocking mechanism for preventing the operation by the trigger or safety button of another operable mechanism. Alternatively it could be an enabling mechanism for selectively operatively coupling and decoupling the trigger or safety button from another operable mechanism, so that the actuating force must be applied as the trigger or safety button is depressed in order to operate the operable mechanism.

The trigger and safety button can similarly be arranged to block or enable another operating element or to operate any other operable mechanism of the lighter.

Furthermore, the operation of the actuation means may similarly be prevented by a disabling or blocking mechanism which is operable by the trigger or the safety button. The actuation force may also be selectively transmitted to the operable component by enabling means operable by the trigger or safety button, so that the user must depress the trigger or safety button at the same time as applying the actuating force to the handle in order for the actuating force to operate the operable component.

It will be understood that numerous variations on these and other interactions are possible within the scope of the appended claims. Some examples of the possible interactions between the actuation surface and the various operable mechanisms of gas lighters will however now be described by way of further illustration.

Referring to Figs. 4A and 4B, the lever 10 of the first lighter is arranged above the fuel reservoir 41 and pivoted about an axle 40 on the lighter body. A fuel release valve 42 is arranged to selectively release fuel from the reservoir via a flexible pipe 43 wliich passes it along the nozzle 2 to a burner where it is ignited to form a flame.

The valve is opened by means of one end 44 of a lever 45 which is arranged to one side of the reservoir and is pivoted about an axle 46 on the lighter body. The valve locates in a slot in the lever end 44. The distal end of the lever 10 is arranged to press downwardly against the other end 47 of the lever 45 so that the lever 45 is pivoted to open the valve and release fuel as the lever 10 is pressed downwardly from the rest position (Fig. 4A) to the operated position (Fig. 4B) by the actuation force A. In this embodiment the fuel release valve 42 and associated mechanism 10, 45 thus forms the operable component, and the lever 10 is biased to the rest position by an internal spring in the fuel valve.

Referring to Figs. 5 A and 5B, in an alternative embodiment the lever 10 is arranged to move a blocking component 50 against the restoring force of a coil spring (not shown) from a blocking position (Fig. 5A) in which it engages an abutment surface 51 of an operating element or other operable mechanism 52 of the lighter, to an unblocking position (Fig. 5B) in which it is disengaged from the abutment surface 51 and free to move in a slot 53. The operating element or operable mechanism 52 may then be moved slidingly in guides 54 in the lighter body in its operating direction B.

The element 52 may form part of the lighter trigger 7, in which case an extension 55 on its rear end may operate the piezoelectric ignition unit or the valve lever. Alternatively it may form part of the piezoelectric ignition unit or valve lever assembly, in which case it may be displaceable in the operating direction B by depression of the trigger or safety button. Alternatively it could form an extension of the safety button, which in turn blocks operation of the trigger, so that an actuating force must be applied to the actuation surface in order to unblock the safety button, which may then be depressed by the user in the operating direction B to unblock the trigger, which in turn may then be depressed to actuate the valve lever and the ignition means.

Referring to Fig. 6, in a further alternative embodiment the fuel pipe 43 is arranged to run through corresponding holes in three plates 60, 61, 62, plates 60 and 62 forming part of the lighter body. The plate 61 is arranged to depend from the distal end of the lever 10 so that the three plates together form a clamp which in the rest position shown forms a disabling device which prevents fuel from passing along the pipe. The lever 10 is biased to the rest position by a leaf spring 63 so that an actuating force must be applied to the actuation surface to release the clamp and allow fuel to pass from the valve to the burner.

Referring to Fig. 7, in a still further embodiment the first lighter is equipped with electronic ignition means instead of piezoelectric ignition means, operated by a battery by means of a switch controlled by the safety button 8. Fuel is released by depression of the trigger 7.

A circuit breaker 70 is arranged so that it normally open circuits the supply from the battery to the switch, and is operable by depression of the lever 10 to close the circuit and enable the switch to work. Thus depression of the trigger 7 will release fuel for combustion, but it will not be ignited unless the safety button 8 is depressed at the same time as the user applies an actuating force to the actuation surface sufficient to depress the lever 10 to close the contacts of the circuit breaker 70. In this embodiment the operable component is thus the circuit breaker 70 which forms a disabling mechanism which normally prevents operation of the ignition means.

Referring to Figs. 8A - 8C, a second utility lighter similar to the first comprises a lighter body 1, a nozzle 2 and a cylindrical inner handle 4 with a collar 5 at one end. A trigger 7 and safety button 8 may similarly be provided for operating various operable mechanisms within the lighter. Unlike the first lighter however, the inner handle has a bore 80 which opens out at the rear end 81 of the inner handle.

Referring also to Fig. 9, a flexible elastomeric handgrip 90 is fixed over the inner handle 4 and sealed by welding or adhesive to the collar 5. The handgrip has a flexible tubular side wall 91 and an end wall 92, which is furnished on its inner face with small projections 93. Axial ribs 94 are provided on the inner surface of the handgrip adjacent its rear end wall 92. The ribs 94 and collar 5 hold the handgrip in spaced relationship from the inner handle, while the flexible side wall 91 forms an actuation surface which is depressed inwardly when the user grips it. The space between the inner handle 4 and the handgrip 90 is filled with gel. When the user applies an actuating force to the handgrip, the gel is squeezed out of the handgrip and through the space between the rear end 81 of the handle and the rear end wall 92 of the handgrip, which are spaced apart by the projections 93, and into the bore 80.

Referring to Fig. 8D, the actuation surface may be operatively coupled to the piezoelectric spark generator 82 by arranging for its plexor to be depressible by a piston 83 slidingly arranged in the bore 80. Separate sealing means (not shown) may be provided for ensuring a pressure-tight seal between the piston 83 and the wall of the bore 80. When the user applies an actuating force to the actuation surface 91, the piston is forced along the bore and the piezoelectric device 82 is actuated.

Referring to Fig. 8E, in alternative embodiments the actuation surface may be operatively coupled instead to other operable mechanisms of the lighter, by arranging a pipe 84 to communicate with the bore 80 so as to transfer the actuating force via the gel within the pipe to the operable component elsewhere within the lighter body. Referring to Fig. 10, a third lighter includes a lighter body 1 which supports an actuation surface similar to that of the second lighter, and a trigger 7. No safety button is provided. A pipe 84 containing gel is arranged to transmit the actuating force from the actuation surface to an expansible bellows 100. The bellows is arranged between an abutment 101 on the lighter body and a lever 102, which in turn is pivoted about an axle 103 mounted on the lighter body.

The trigger 7 is arranged to operate a piezoelectric spark generating device 104 by means of a flexible extension 105 which is mounted on the trigger at one end and has an abutment surface 106 at the other. In the operative position, the abutment surface 106 engages a corresponding abutment surface 107 on the plexor of the piezoelectric device, so that as the trigger is depressed in the operating direction C the piezoelectric device is compressed to produce a spark at the burner. The valve lever 108 is operated by an extension on the trigger, which cannot be seen in this view.

The distal end of the flexible extension 105 is moveable in a direction transverse to the operating direction C of the trigger, and is inherently resilient so that it is normally biased to the rest position as shown. In this position the abutment surfaces 106, 107 are misaligned so that depression of the trigger in the direction C will cause the extension 105 to ride up the sloping top surface 109 of the piezoelectric plexor without compressing it, and hence will not produce a spark.

In order to enable operation of the trigger to ignite the released fuel, the user must apply an actuating force to the actuation surface sufficient to displace a minimum volume of gel, which is carried by the pipe 84 to the bellows 100, causing the bellows to expand. This in turn depresses the lever 102 in the downward direction D, which in turn presses with a sliding abutment surface 110 against the flexible extension 105, causing the abutment surfaces 106, 107 to move into alignment. The trigger may then be depressed in the direction C to transfer the trigger pressure to the piezoelectric device and so produce a spark. The operable component thus comprises an enabling device which enables actuation of the trigger.

Referring to Fig. 11, a fourth lighter similarly comprises an actuation surface, a trigger 7, a piezoelectric device 104, and a valve lever 108, together with a flexible extension 105 mounted on the trigger, and these parts work in the same way as in the third lighter. The trigger is enabled by depressing the extension 105 by means of a lever 111 similar to that of the third lighter, which pivots about an axle 112 in the lighter body 1. In this embodiment however the lever is actuated by depression of an integral safety button 8 which protrudes from the top of the lighter casing 1.

A blocking device is provided for preventing the depression of the safety button, and comprises a slider 113 which is slidingly received within the lever 111 and moves together with it in the downward or enabling direction D when the safety button 8 is depressed. The slider is biased to the rest position as shown by a coil spring 114, and in this position an abutment surface 115 on the bottom of the slider abuts against a corresponding abutment surface formed by the upper surface of a projection 116 from the lighter body.

In order to unblock the safety button so that it can be depressed to enable the trigger, the slider must be displaced in the unblocking direction E so that the surfaces 115, 116 are no longer in abutment. This is achieved by applying an actuating force to the actuation surface, which displaces a sufficient quantity of gel via the pipe 84 into an expansible bellows 117. The bellows expands against an abutment 118 to force a plunger 119 and pushrod 120 in the unblocking direction E against the restoring force of a coil spring 121. The pushrod bears slidingly on the end face 122 of the slider 113 so as to urge it to the unblocking position. In this embodiment the actuation means is thus arranged to operate a blocking mechanism which in turn releases the safety button for depression, which in turn enables actuation of the ignition means by depression of the trigger. In the disabled or rest condition, the trigger may be depressed freely without producing a spark.

Referring to Fig. 12, in a development, the third lighter is formed as shown in Fig. 10 but with an additional blocking device which normally prevents depression of the lever 102 in the enabling direction D by the actuating force. The blocking device comprises a projection 130 formed integrally with the lever 102 and having an abutment surface 133. A sliding safety button 8 is provided on the top of the lighter casing 1, and has an integral downward projection 132 with a corresponding abutment surface 131 which in the rest position as shown engages the abutment surface 133 to obstruct depression of the lever 102.

When the user applies an actuating force to the actuation surface, the lever 102 will not move downwards and the trigger will not be enabled unless the user also slides the safety button forwards in the unblocking direction F against the restoring force of a spring (not shown). The safety button thus forms a blocking device which selectively operatively decouples the actuation surface from the operable component, which in this embodiment is the enabling means 100, 102, 105 and associated components. The piezoelectric device and fuel lever may then be operated by depressing the trigger to ignite the lighter.

Referring to Fig. 13, the first lighter is shown with the protective frame and gel capsule removed and the casing partially cut away to show a development of the fuel release mechanism of Figs. 4A and 4B. In this embodiment the axle 46 of the fuel release lever 45 is mounted at the distal end 140 of an enabling lever 141 rather than on the lighter body. The enabling lever 141 is mounted in turn on an axle 142 on the lighter body so that its proximal end 143 is depressible by depression of the safety button 8 in the enabling direction G. The safety button 8 and the proximal end 143 of the enabling lever are biased upwardly to the rest position by spring means, which cannot be seen in this view.

In the rest position, the axle 46 of the fuel lever is moved downwards by the enabling lever so that when the user applies an actuating force A to the actuation surface so as to depress the lever 10, the end 47 of the fuel lever is not depressed by the distal end of the lever 10 and fuel is not released. In order to operate the lighter, the user must first depress the safety button 8 to the enabled position as shown, so that the axle 46 is raised to its operating position. In this position the actuating force may be applied to depress the lever 10, which will bear against the raised end 47 of the fuel release lever so as to open the valve. In this embodiment the safety button thus forms an enabling device which selectively couples and decouples the actuating force from the operable component, which in the example illustrated is the fuel release mechanism.

Referring to Fig. 14, a disabling device is illustrated whereby the actuation means may be selectively disabled from operating the operable component. The gel is communicated to the operable component via a pipe 84 which is arranged to pass through a clamp similar to that shown in Fig. 6. In this embodiment the central plate 150 of the clamp is moveable from the disabling position shown, in which the pipe 84 is sealed, to the enabling position, in which gel is allowed to pass along the pipe, by a safety button 8 which protrudes from the lighter body 1 and is depressible by the user against the restoring force of a leaf spring 151. When the user applies an actuating force to the actuation surface, the gel is prevented from coupling the actuating force via the pipe to the operable component unless the user first releases the clamp by depressing the safety button in the direction H. A one way valve is provided in parallel with the clamp for permitting gel to flow from the operable component towards the actuation surface. In this embodiment the safety button 8 thus forms a disabling means for operatively decoupling the actuation surface from the operable component until the safety button is depressed. In an alternative embodiment, an enabling device may comprise a valve or clamp which is arranged to selectively connect the body of displaceable material with an internal reservoir or with another body of displaceable material. Operation of the valve will then selectively dissipate the actuating force applied by the user by displacement of the material into the other reservoir or body of material so that the operable component is not operated. Two bodies of material with separate actuation surfaces may for example be arranged to communicate in this way via a valve controlled by a safety button. A pressure relief valve may also be provided. The lighter may thus be arranged to ensure that excessive pressure applied to the actuating surface is safely dissipated by displacement of the material.

Referring to Fig. 15, 16 and 17, a fifth lighter comprises a lighter body 200 containing a fuel reservoir and supporting a valve operable to release fuel from the reservoir to a burner 201, and a metal shield 202 surrounding the burner. The lighter illustrated is of the roll-and-press type and includes an ignition system comprising a flint which is pressed resiliently against a serrated sparkwheel. The sparkwheel is mounted between two thumbwheels 203 to form a wheel assembly which is rotatable by the user to produce a sheaf of sparks. The sparkwheel cannot be seen in this view since it is covered by a protective strip 204. The valve is operable by a fuel release lever 190 whose proximal end 205 forms a pad which in use is pressed downwards in the direction I by the user so as to lift the distal end of the lever 190, which in turn lifts the valve assembly to release fuel to the burner.

The lower part of the lighter body comprises a rigid inner body 206 with smooth and generally continuous sides and base, which is covered by a protective frame 207. The protective frame is formed similarly to that shown in Fig. 2 with a generally tubular wall 208, which in this case has a cross sectional shape which is roughly rectangular but with rounded sides, a closed bottom end 209 and an open top end 210. A recess or collar, which cannot be seen in these views, is formed at the upper end of the inner body to receive the upper end 210 of the frame so that the remainder of the frame, including the closed bottom end 209, is spaced apart from the inner body. At each corner 211 of the frame a pair of internal ribs extend inwardly from the frame to support the frame rigidly against the inner body. Four cutouts 212 are formed, one respectively in each of the two narrow sides 213 and two broad sides 214 of the frame. Of course, only one cutout might alternatively be provided.

A gel capsule 215, shown in Fig. 17 disassembled from the lighter body, is formed generally as a cross with four arms 216 corresponding to the four sides of the body and joined by a central portion 217. The capsule comprises a double walled flexible membrane, having an inner wall which is to the back in the view shown in Fig. 17 and an outer wall 218. The inner and outer walls are joined by edge walls 219 to form an envelope defining a continuous space between the outer and inner walls so that each of the four arms 216 communicates with the other arms via the central portion 217. The capsule is filled with a gel.

During assembly, the capsule is arranged around the inner body 206 so that the inner wall of each arm 216 lies against one side of the inner body and the inner wall of the central portion 217 lies against the base of the inner body. The protective frame is then slid upwards over the assembled inner body and capsule with the inner ribs in between the arms until its open top end 210 snaps into a retaining groove in the collar. The capsule 215 is then retained snugly in position between the base, sides and collar of the inner body and the base and sides of the protective frame.

Four textured grip pads 220 are formed on the outer wall 218 of the capsule, one on each of the arms 216, so that in the assembled position they are accessible respectively through the cutouts 212. The grip pads form part of the flexible membrane and thus form together an actuation surface, which extends substantially all the way around the lighter body and which in use may be gripped by the user to apply an actuating force via the gel and the inner wall of the membrane to an operable component of the lighter.

Since the protective frame 207 is substantially rigid and is rigidly spaced apart from the inner body 206 by its internal ribs, the user must depress the actuation surface 220 by pressing the pulp of his fingers and palm into the cutouts 112. In alternative embodiments, the cutouts may be formed as relatively narrow apertures or slots which are too small to allow a child to insert its finger through the frame; this makes it still more difficult for a child to operate the lighter.

Although the cigarette lighter illustrated is a flint ignition lighter of the roll-and- press type, it will be appreciated that the arrangement of the fifth lighter will be equally applicable to piezoelectric and other types of cigarette lighter. The actuation surface may be operatively coupled to many different operable mechanisms of the lighter, whether the lighter is of the flint ignition, piezoelectric or other types, and many of the embodiments already described with reference to the first, second, third and fourth lighters may equally be applied, mutatis mutandis, to cigarette lighters as well as to utility lighters. Nevertheless, some examples of ways in which the actuating force may be operatively coupled to an operable component of a cigarette lighter are discussed below by way of further illustration.

Referring particularly to Fig. 16, the operable component may comprise a lever 230 which is hinged at its lower end 231 in the inner body 206 so that its upper end 232 is depressible inwardly into the inner body in the actuating direction J. In the example shown, an abutment surface 233 is formed on the upper end of the lever 230 so that in the rest position shown it abuts against a downwardly projecting wall 234 which is formed on the thumb pad 205. The lever is biased to the rest position by a leaf spring, which cannot be seen in this view, and thus forms a blocking mechanism which prevents fuel release by preventing depression of the fuel release lever. To operate the lighter, the user must apply a sufficient actuating force over a sufficiently large area of the actuation surface 220 so as to displace the gel enough to pivot the lever 230 inwardly in the direction J until its abutment surface 233 is clear of the wall 234. The thumb pad 205 may then be depressed in the downward direction I to operate the valve.

In alternative configurations, the lever 230 may be arranged to directly operate a valve lever or piezoelectric ignition mechanism, or another operable mechanism of the lighter.

Referring to Fig. 18, in an alternative embodiment the fifth lighter is provided with a pushrod 240 in place of the usual flint biasing spring. The pushrod is guided in a bore which runs axially through the centre of the lighter body from its upper end, which bears against the flint 244, to its lower end which terminates in a flat plate 241. The plate is biased downwardly by a coil spring 242 which abuts against the base 243 of the inner body 206. In use, the user applies an actuating force to the actuation surface 220 so that gel is displaced into the central portion 217 of the capsule. The plate 241 is then pressed upwardly by the inner wall of the central portion 217 of the gel capsule, which is trapped between the plate 241 and the inner surface of the closed bottom end 209 of the protective frame. This urges the pushrod 240 upwards against the flint 244, which in turn is pressed upwards against the sparkwheel so as to produce a sheaf of sparks when the user rotates the wheel assembly. In the rest position, the coil spring 242 relieves the pressure against the flint, which does not then produce sparks when the wheel assembly is rotated. In this embodiment, the operable component thus comprises an enabling device for enabling the normal operation of the ignition means.

Referring to Fig. 19, in a final alternative embodiment the lighter includes a flat plate 250 which slides up and down in guides formed in the upper end of the inner body 206. One edge wall 219 of the gel capsule 215 bears upwardly against a lower edge of the plate 250 so that when the user applies an actuating force to the actuation surface 220 the plate is urged upwardly in the actuating direction K. The fuel release lever 190 is pivoted on an axle 191 which in normal lighters would be housed in the lighter body. In this embodiment however the lever axle 191 is housed in a hole 251 in the plate 250, so that the axle 191 moves up and down with the plate 250. In the downward position of the plate and axle, the fuel release lever is inoperable to open the valve.

In order to operate the lighter, the user must squeeze the actuation surface 220 so as to apply an actuating force to the plate 250, which then moves upwards in the direction K together with the lever axle 191. This places the lever axle 191 in the operable position, so that when the user presses down on the thumb pad 205 which forms the proximal end of the fuel release lever 190, the lever pivots about its axle 191 to raise its distal end and hence open the valve. A second plate corresponding to the plate 250 may be provided on the other side of the lighter for similarly housing the other end of the fuel lever axle.

In this embodiment the operable component thus comprises disabling means for preventing the normal operation of the fuel release mechanism. In alternative configurations, rather than housing the fuel release lever axle, the plate 250 could be arranged for example to release a braking device arranged to normally impede the rotation of the wheel assembly, or to raise a protective plate arranged between the sparkwheel and the burner for normally preventing the passage of sparks, or to directly actuate the valve.

In all of the above embodiments the volumetrically displaceable material is preferably a noncompressible fluid such as a gel or a liquid. Alternatively however it may be a gas, and the minimum volumetric displacement and actuation force which the user is required to apply to the actuation surface may then be determined in part by the resulting compression of the gas. In alternative embodiments, the volumetrically displaceable material may be a plastically deformable material, such as a modified elastomer, perhaps moulded around the lighter body so as to form the handle so that the surface of the volumetrically displaceable material itself forms an actuation surface and no separate membrane or containing bladder is required. The actuation surface may itself comprise a resilient membrane which tends to return the operable component to the rest position by negative pressure of the displaceable material following release of the actuation surface by the user.

The minimum actuation force which the user is required to apply may also be dependent on the ratio of the area over which the actuation force is applied by the user to the volumetrically displaceable material, to the area over which the volumetrically displaceable material couples the actuation force to the operable component, forming a type of hydraulic system which divides or multiplies the effort of the user, and the biasing forces involved are selected accordingly.

In alternative embodiments the actuation surface need not necessarily comprise a flexible membrane. Thus for example the gel or fluid might be contained within a vessel provided with a plunger or piston which is displaced by the user by means of pressure against a flap or handle, or even by pulling on a tension element such as a lever, ring or the like.

In still further alternative embodiments, two or more distinct actuation surfaces may be provided, which may each communicate with the same body of volumetrically displaceable material, or alternatively with separate bodies of volumetrically displaceable material. Both surfaces must then be gripped by the user so as to apply the required actuation force to each body of material, either sequentially or simultaneously, in order to achieve ignition. The actuation surfaces may be spaced apart on the outer casing of the lighter so as to make it difficult for a child's small hand to reach both surfaces together. For instance, one actuation surface may be arranged to actuate the lever and the other, the ignition mechanism of a gas lighter, so that both must be gripped simultaneously with sufficient force and over a sufficient surface area in order to achieve ignition.

Alternatively one actuation surface may be arranged to operate an operable component which enables or disables the operation of the other actuation surface, which in turn operates another operable mechanism of the lighter.

In summary, embodiments provide a child resistant actuation mechanism comprising a flexible actuation surface which is depressible by the user to couple an actuating force via a body of volumetrically displaceable material, such as a gel, to an operable internal component. The operable component may be an ignition or fuel release mechanism in a gas lighter, or an enabling or disabling device which interacts with another operable mechanism. The operation of the actuation means may also be enabled or disabled by another operable mechanism or by an operating element. The user may be required to apply a minimum force over a minimum surface area so as to achieve a minimum volumetric displacement of the gel in order to operate the operable component.

The invention may be applied to any user operable device as well as to gas lighters. For example, retractable craft knives and the like comprise a sharp blade which is retracted into a handle for safety and can be extended by means of a button or the like. It is therefore desirable to prevent small children from deploying the blade and injuring themselves. Thus a craft knife with a retractable blade may be provided with a safety interlock which prevents deployment of the blade until the interlock is actuated; a volumetrically displaceable material is arranged to form part of the outer casing of the knife, so that sufficient compression of the material actuates the interlock and releases the blade or the button which extends the blade. Electrical remote control units, such as for example wireless controls for stairlifts and bathlifts, and power tools such as drills and the like may similarly cause accidents or injury if operated by small children. These and other devices may similarly be provided with a volumetrically displaceable material arranged to form part of the outer surface of the device which when displaced bears pressingly on a moving internal operable component, such as a spring biased electrical contact, which actuates or enables actuation of the device. Child safety gates and safety buckles may similarly be operated by arranging an external actuation surface with a body of gel which is operatively coupled to an internal latch mechanism. It is to be understood therefore that the embodiments illustrated are not exhaustive, and numerous adaptations and developments may be made thereto without departing from the scope of the claims.

Claims

1. A child resistant actuation means for a device, the device having at least one operable component;

characterised in that the actuation means comprises a volumetrically displaceable material

together with an actuation surface accessible by a user of the device,

wherein the operable component is operatively coupled to the actuation surface by the material

such that the operable component is operable by the application by the user of an actuating force to the actuation surface.

2. A child resistant actuation means according to claim 1, characterised in that the device has an outer surface

and the actuation surface comprises a flexible membrane forming part of the outer surface.

3. A child resistant actuation means according to claim 2, characterised in that the operable component is operable by the application by the user of an actuating force to at least a minimum surface area of the membrane

but inoperable by the application by the user of an actuating force to less than the minimum surface area of the membrane.

4. A child resistant actuation means according to claim 1, characterised in that the operable component is operable by the application by the user to the actuation surface of at least a minimum actuating force

but inoperable by the application by the user to the actuation surface of a force less than the minimum actuating force.

5. A child resistant actuation means according to claim 4, characterised in that biasing means are provided for applying a biasing force to resist the actuating force,

such that the minimum actuating force is related to the biasing force.

6. A child resistant actuation means according to claim 1, characterised in that the operable component is operable by the application by the user of an actuating force to the actuation surface so as to displace at least a minimum volume of the material,

but inoperable by the application by the user of an actuating force to the actuation surface so as to displace less than the minimum volume of the material.

7. A child resistant actuation means according to claim 1, characterised in that the displaceable material comprises a gel.

8. A child resistant actuation means according to any preceding claim, characterised in that the device is a gas lighter,

the gas lighter including a body, a reservoir containing fuel, and at least two operable mechanisms, the operable mechanisms including valve means for releasing fuel from the reservoir

and ignition means for igniting the fuel.

9. A child resistant actuation means according to claim 8, characterised in that the at least one operable component is the valve means.

10. A child resistant actuation means according to claim 8, characterised in that the at least one operable component is the ignition means.

11. A child resistant actuation means according to claim 8, characterised in that the lighter includes a disabling mechanism,

wherein the disabling mechanism is normally effective to prevent operation of at least one operable mechanism;

and the lighter further includes an operating element,

the operating element being operable by the user to place the disabling mechanism in an enabling condition in which it does not prevent operation of the said at least one operable mechanism.

12. A child resistant actuation means according to claim 8, characterised in that the at least one operable component comprises a disabling mechanism,

wherein the disabling mechanism is normally effective to prevent operation of at least one operable mechanism and is operable by the application by the user of an actuating force to the actuation surface to place it in an enabling condition in which it does not prevent operation of the said at least one operable mechanism.

13. A child resistant actuation means according to claim 8, characterised in that the lighter includes enabling means for selectively transmitting the actuation force to the operable component,

together with an operating element operable by the user to change the enabling means from a normal, disabled condition,

wherein the application by the user of an actuating force to the actuation surface does not operate the operable component,

to an enabled condition wherein the application by the user of an actuating force to the actuation surface does operate the operable component.

14. A child resistant actuation means according to claim 8, characterised in that the lighter includes at least one operating element operable by the user,

wherein the operating element is normally operatively decoupled from at least one operable mechanism

such that operation by the user of the operating element does not operate the said at least one operable mechanism;

and the operable component comprises enabling means,

wherein the enabling means is operable by the application by the user of an actuating force to the actuation surface to operatively couple the operating element to the at least one operable mechanism,

such that the at least one operable mechanism is operable by the user by operation of the operating element.