Field of the Invention

This invention relates to a handle for an oral care implement comprising a coupling mechanism for interlocking detachable attachment with a head of the implement. The brush head may be replaced periodically, especially when it has worn out.

Background of the Invention

EP3501334 B1 (Gillette) discloses an oral care implement comprising a head repeatedly attachable to and detachable from a handle. The head is made from a material whose density is 0.5 to 1.2 g/cm ³ whereas the handle is made of a material whose density is 2.1 to 3.1 g/cm ³ . The material of the head is non-magnetic and/or non-ferromagnetic, preferably polypropylene and that of the handle comprises at least one of a magnetic or a ferromagnetic material. The technology provides more comfort and improved quality perception as well as better maneuverability of the oral care implement in the oral care cavity during brushing. The relatively high weight of the handle material provides a user with high-quality perception and comfortable feeling during use of the oral care implement.

US2018235356 A1 (Colgate) discloses a toothbrush having a base structure with a transparent shell component that surrounds a core component. The core is formed of a rigid material and has decorative elements embedded within its body which are visible through the shell.

US2015164211 A1 (Hohlbein Douglas) discloses an oral care implement having a handle that includes a core comprising recycled material and a sheath. The head is connectable to the handle. Due to the use of recycled material, there is comparatively lesser impact the environment. In addition, the user gets a firm surface to hold during use the product is safe to use. The recycled material may comprise a polymer, such as a thermoplastic polymer like ABS.

While ergonomics, aesthetics and grip of the handle are features important from a user’s perspective; consumer safety, impact resistance and ease of assembly/disassembly are also important. For example, toothbrushes, and in this case, more particularly the handles, often tend to slip from a user’s hands and fall on the ground which is usually composed of tiles or hard flooring. In such case, it is necessary that the handle has a certain minimum impact resistance. On the other hand, the extent of force that is required for locking and unlocking via the inter-engaging locking means is also an important feature, especially where the locking means involves an interference- or snap- fit such as the one disclosed in CN212938595U (Shanghai Shift). While certain extent of force is necessary to lock and unlock every type of fitment, if too much force is required for unlocking, some users such as the aged and children, may not be able to use the brush with ease. On the other hand, if the fitment unlocks under too little force, then there is technical problem of consumer safety, because the disengaged head may enter the mouth of the user leading to choking hazard.

Summary of the Invention

It has been determined that at least some of the aforesaid problems can be solved by the present invention.

In accordance with a first aspect disclosed is a handle for an oral care implement, said handle comprising a coupling mechanism for an interlocking detachable attachment of said handle with a head of said oral care implement, where said handle comprises a non-movable core component having weight (wi) inside a sheath component having weight (W2), wherein, ratio of wi:w2 is from 1 :0.5 to 1 :0.05 and cross-sectional area of said core component accounts for 50 to 90% of cross-sectional area of said handle, wherein said coupling mechanism comprises a base part embedded inside said handle and an operative part that projects outwardly for said detachable attachment.

In accordance with a second aspect disclosed is an oral care kit comprising a handle of the fist aspect and a head comprising a counterpart mechanism for said detachable attachment.

Detailed Description of the Invention

The invention relates to a handle for an oral care implement, said handle comprising a coupling mechanism for interlocking detachable attachment of said handle with a head of said oral care implement, where said handle comprises a non-movable core component having weight (wi) inside a sheath component having weight (W2), wherein, ratio of wi:w2 is from 1 :0.5 to 1 :0.05 and cross-sectional area of said core component accounts for 50 to 90% of cross-sectional area of said handle. area of said core component accounts for 50 to 90% of cross-sectional area of said handle, wherein said coupling mechanism comprises a base part embedded inside said handle and an operative part that projects outwardly for said detachable attachment. Oral care implement means and includes all implements for oral care. It is preferred that the implement is a manual toothbrush, tongue cleaner or an interdental brush. Depending on the purpose and application of the oral care implement the head part is preferably a brush head. Alternatively, it is a tongue cleaning head. Preferably when the implement is a manual toothbrush, the head is formed of lightweight plastic and comprises an array of bristles. When the implement is a manual toothbrush the head part is preferably formed of a recycled or recyclable plastic material. Alternatively, it comprises a tongue cleaner. Further alternatively it comprises a brush head comprising bristles and a tongue cleaner.

In embodiments of the invention the head and the first part of the handle are preferably formed of a plastic material.

In such embodiments of the invention, the head, which is to be replaced regularly, may be produced relatively efficiently and with a relatively low weight to reduce manufacture and transport costs. Further, the plastic material may be a recyclable plastic material, hence further reducing unsustainable waste with the product in comparison to known toothbrushes.

In such embodiments of the invention, the bristles may be used to clean the teeth and mouth. Different embodiments of the invention may include different types of bristle designs to achieve different types of cleaning, e.g., standard, sensitive, whitening. The user may interchange heads with different bristle designs to achieve different types of cleaning while using the same handle. Therefore, the invention allows a user to have greater flexibility in their teeth-cleaning habits without having to own multiple different toothbrushes.

Function of the interlocking detachable attachment is to enable a user to inter-engage a replaceable head with the handle so that the implement becomes usable. After single use the implement may be kept aside, without dismantling, until the need arises next time. A head may need to be changed in case it is worn out or when the user may want to change for a related application, like tongue cleaning after brushing, with the same handle but changing the head.

The coupling mechanism comprises a base part embedded inside the handle and an operative part that projects outwardly for the detachable attachment. The operative part may have any kind of means for interlocking with the head. Preferably the operative part comprises press-fitting means, screw threads, bayonet or magnetic means for detachable attachment with correspondingly configured head. It is particularly preferred that the coupling mechanism in the handle comprises a shaft provided with a card slot and the corresponding head has an elastic clip provided on the cavity wall of the connection cavity where the elastic clip can be engaged with the card slot.

Alternatively, the coupling mechanism comprises a bayonet element and a socket; the bayonet being comprised in the operative part of the handle and the socket being formed within the head.

The socket preferably comprises an axis, an opening and first and second channels which channels are positioned transversely opposite one another, wherein each channel comprises: a first channel portion extending axially from the opening and having a first transverse dimension, and a second channel portion extending axially from the first channel portion having a second transverse dimension larger than the first transverse dimension; and the bayonet element comprises an axis and first and second protrusions, which protrusions are positioned diametrically opposite one another, wherein each protrusion extends outwardly from the bayonet element, is axially receivable by a respective first channel portion and is transversely receivable by a respective second channel portion.

The bayonet element may be inserted into the socket by first aligning each of the first and second protrusions with the respective first channel portion and then moving the bayonet element axially into the socket. Once the bayonet element is moved axially into the socket such that each protrusion moves through the respective first channel portion and into the respective second channel portion, the bayonet element may be rotated about its axis relative to the socket such that each protrusion moves transversely across the respective second channel portion.

In one aspect, preferably the core component is integral with the coupling mechanism.

Alternatively, the core component is separate from said coupling mechanism with a space or spacer therebetween.

It is further preferred that the coupling mechanism is so configured that the force necessary to disengage a handle from a head is from 8 to 45 Newtons.

It is preferred that length of the core component is 55 to 90 % of the length of the handle. The length of said handle needs to be proportionate and should be sufficiently long to allow a user to grip it comfortably. It is preferred that length of the handle is from 8 cm to 16 cm. It is further preferred that length of the handle is 10 to 14 cm.

The handle is elongated, and it may be of any shape such that the cross-section of the handle is preferably a regular polygon such as triangular or square. Alternatively the cross section of the handle is preferably circular or oval. That us because such shapes are comparatively easier to mould and manufacture. Further preferably when said cross-section is circular, the diameter reduces progressively from the rear end which is the widest part towards the front end which is the narrowest part of said handle. The ratio of the cross-sectional area at said rear end to that at the front end is from 1 :0.5 to 1 :0.8. It is further preferred that diameter of the handle at the rear end is 1 to 3 cm and at the front end is from 0.5 to 2.5 cm. Further, it is preferred that weight of the sheath component of the handle is from 8 to 16 grams, more preferably 8 to 16 grams, more preferably 10 to 14 grams. Weight of the sheath component of the handle is less than weight of the core component. In one embodiment, the sheath component is composed of plastic, preferably ABS.

It is preferred that the core component comprises an end section at the rear end opposed to said coupling mechanism at the front end. In such cases, the handle comprises a resilient gasket between said core component and said end section. Preferably the handle comprises an end cap after said end-section. The end cap is preferably made of plastic, or an elastic material or even a hard material such as a metal. It is preferred the length of the end cap is 0.5 to 1.5 cm, more preferably 0.6 to 1.2 cm.

It is preferred that the core component is elongated and is composed of a metal, alloy, metalloid, high-density plastic, wood, bamboo, ceramic or glass. More preferably the core component is made of steel. It is preferred that length of the core component is from 12 cm to 8 cm. The shape or cross-section of the core component is not a limiting feature however it is preferred that the cross-section of the core component is circular. In such a case, it is preferred that diameter of the core component is 0.3 to 0.6 cm. Weight of the core component is preferably from 10 to 20 grams, more preferably 12 to 18 grams, more preferably 14 to 16 grams.

Preferably the total weight of the handle is 20 to 35 grams, more preferably 25 to 32 grams.

It is preferred that the sheath is secured to the core by interference fit. This could be achieved by variety of means. It is preferred that the core comprises knurlings for the interference fit. Preferably the sheath is laid over the core by moulding, layering or lamination. Preferably the sheath is laid over by injection moulding.

Further preferably the handle comprises a thumb-rest. It is meant for a user to rest his/her thumb for proper grip. The thumb rest is preferably made of an elastomer having Shore A hardness from 30 to 60. Preferably the thumb grip is 1.2 to 2.6 cm. Preferably the thumb-rest comprises a gripenhancing feature.

Further preferred features of the handle

It is preferred that the sheath component is transparent such that said core component is visible therethrough. Preferably the core component comprises decoration. The decoration could be in the form of artwork, designs, inscription, emblem, logo, hallmark that can be so seen through the sheath.

The head may be replaced on a regular basis by the user (once every 3 to 4 months for example), may be formed from substantially less material than known toothbrushes, thereby reducing the waste associated with regularly replacing the head.

Further, as the packaging material required per head is much less than the packaging material required per toothbrush for known toothbrushes. Hence the waste associated with packaging of the invention is reduced compared with that of known toothbrushes.

Brief Description

Fig.1 is exploded view of an embodiment of a handle in accordance with the invention.

Fig.2 is sectional view of an embodiment of a handle in accordance with the invention.

Detailed Description

Referring to Fig.1 which shows an exploded view of an embodiment of a handle (1) in accordance with the invention, seen here is the handle (1) with the coupling mechanism (2) for interlocking detachable attachment of the handle (1) with a head of the oral care implement. Thbe head is not shown/included in this figure. The handle (1) has circular cross-section throughout. The non-movable core component (3) is inside the sheath component (4). In this embodiment, the core component (3) is not integral with the coupling mechanism (2) because the two are separated by a space created by a spacer (5) therebetween.

Diameter of the handle (1) reduces progressively from the rear end (B), which is the widest part, towards the front end (A) which is the narrowest part of said handle (1).

Length of the core component (3) is about 75% % of the length of the handle (1).

The core component (3) has an end section (6) at the rear end opposed to said coupling mechanism (2) at the front end. Handle (1) has an end cap (7) after the end-section (6). The handle has thumb-rest (8).

The coupling mechanism (2) comprises a base part (2A) embedded inside the handle (1) and an operative part (2B) that projects outwardly for the detachable attachment.

Fig.2 is sectional view of an embodiment of a handle in accordance with the invention in assembled form. To explain the features seen in this view, use will be made of numerals 21 to 29, where 21 would correspond with feature 1 of the Fig.1 and so on.

Seen here is the handle (21) with the coupling mechanism (22) for interlocking detachable attachment with a head of the oral care implement. The handle (21) has circular cross-section throughout. The head is not shown in the figure.

The non-movable core component (23) is inside the sheath component (24). In this embodiment, the core component (23) is integral with the coupling mechanism (22).

Diameter of the handle (21) reduces progressively from the rear end (B) which is the widest part, towards the front end (A) which is the narrowest part of the handle (21).

Length of the core component (23) is about 75% % of the length of the handle (21).

The core component (23) has an end section (26) at the rear end (B) opposed to the coupling mechanism (22) at the front end (A). Handle (1) has an end cap (27) after the end-section (26). The handle has thumb-rest (28). In this embodiment, the coupling mechanism (22) comprises a base part (22A) embedded inside the handle (21) and an operative part (22B) that projects outwardly for the detachable attachment. The invention will now be explained with the help of non-limiting examples.

Examples

Example 1 : Impact test

This experiment was done to evaluate resistance of the materials with which the toothbrush is made, and as aforesaid, were conducted at 23±5°C and relative humidity 50±10 %. Size and dimensions pertaining to the handle were as follow:

Handle length: 12.5 cm

Handle cross-section: circular, tapering towards the front end (as in Figures 1 and 2) Diameter at front end - 0.9 cm, at rear end 1.5 cm.

Weight of the handle 28 grams

Weight of core component - 12 grams; weight of core component (steel) = 16 grams Coupling mechanism - as described in CN212938595U

Briefly, the procedure was as follows:

A handle was held with a clamping torque of 0.7 ± 0.03 Nm. The tuft-hole plane was perpendicular to the bottom plane of the clamping unit. The clamping unit was set on the impact tester so that the striker edge could hit the handle at the centre of the tuft-hole area from the opposite side of the tuft-hole surface.

Length between the top plane of the clamping unit and the centre of the tuf thole area was adjusted to 55 mm.

The impact velocity of the striker was dependent on its height at the beginning of the test, or the vertical distance of fall of the pendulum striking edge.

The Initial energy was kept at 2.75 ± 0.1 Joules. After the test, all samples were labelled and separated into two sets as fractured (F) or not fractured (NF). In the case of fractured toothbrushes, the angle of the pendulum and the absorbed energy were determined.

It was expected that a handle should absorb at least 0.8 J without showing any signs of fracture. The data is summarised in Table 1. Table 1 sted samples absorbed more than the minimum energy of 0.8 J with