Patent EA-003506-B1 (EA)
Title: Toothbrush
Inventor: KRAMER HANS
IPC: A46B5/00
Filed: 2000-11-14
Abstract: 1. A toothbrush comprising a combination of a grip handle (11) and a replaceable head (12) which carries a dental cleaning tool, the handle (11) and head (12) being disposed along a longitudinal head-handle direction in which; the grip handle (11) is elongated and at an end thereof has a socket (15) therein which has an opening (16) facing in the direction of the head (12), and socket side walls (17) extending away from the opening in a depth direction, the head (12) has a pin (14) oriented in the direction of the handle (11) and which is insertable into the socket (15) in the depth direction of the socket (15), the pin being releasably engageable with the socket (15), characterized in that at least part of the socket side walls (17) comprises a resiliently deformable elastomer material (18) different to the material pin (14) and resiliently deformable when the pin (14) is inserted into the socket (15), so as to retain the head (12) in engagement with the handle (11) under the stresses experienced by the toothbrush during use in toothbrushing. 2. A toothbrush according to claim 1 characterized by a sufficient coefficient of friction between the elastomer and the part of the pin (14) or socket (15) which is in contact with the elastomer to help to retain the pin (14) in the socket (15) by friction. 3. A toothbrush according to any one of claims 1, or 2 characterized in that the head (12) is extended longitudinally from its base to form an integral neck region between the base of the head (12) and the handle (11), and the pin (14) is located at the end of the neck nearest to the handle (11). 4. A toothbrush according to any one of the preceding claims, characterized in that the elastomer material (18) is situated in places on the pin (14) and/or the socket side wall so as to be resiliently compressed between the pin (14) and the socket side wall when the pin (14) is inserted into the socket (15) and thereby provides resilient and/or frictional grip between the pin and the socket side wall (17). 5. A toothbrush according to any one of claims 1 to 4 characterized in that there is at least one cam surface (56) on a side surface of the pin (14), the cam surface has a retaining shoulder (57) at a surface thereof nearest the head (12), and the socket side wall (17) has a resiliently deformable part (510) having a corresponding retaining shoulder (511) which is biased outwardly from its rest position by the action of the cam surface (56) when the pin (14) is inserted into the socket and the pin (14) is moved in the depth direction into the socket, then springs back toward its rest position behind the retaining shoulder (57) of the pin (14) when the retaining shoulder (57) of the pin (14) has passed the retaining shoulder (57) of the socket, and the resiliently deformable part (510) of the socket side wall (17) is made partly of plastic and partly of the elastomer material (18). 6. A toothbrush according to claim 5 characterized in that the cam surface (56) comprises a projection from a side surface of the pin (14) and the resiliently deformable part (510) of the socket side wall (15) comprises a pair of jaw parts on opposite sides of the socket (15) which are urged apart by contact with the cam surface (56) and pressure from the cam surface (56) as the pin (14) is inserted into the socket (15), and then close behind the cam surface(s) (56). 7. A toothbrush according to any one of claims 5 or 6 characterized in that within the socket (15) deeper than the retaining shoulder of the socket there is one or more cavity (59) in the side wall, which receive(s) the cam part(s) of the pin (14) when this/these pass the retaining shoulder(s) (511) of the socket side walls (17) on insertion of the pin (14) into the socket (15). 8. A toothbrush according to claim 7 characterized in that such cavity(ies) (59) contain an elastomer material (512) which is resiliently deformed when a cam part of the pin (14) is received therein. 9. A toothbrush according to any one of claims 5 to 8 characterized in that the retaining shoulder (511) is located in the longitudinal half of the socket which is nearest to the opening of the socket (15). 10. A toothbrush according to any one of claims 1 to 4 characterized in that part of the socket side wall comprises the resilient deformable elastomer material (18), and the pin (14) has at least one sideways displaced part such that when the pin (14) is inserted into the socket (15) the at least one displaced part engages with the elastomer material (18) by deforming the elastomer material when the pin (14) is inserted into the socket (15). 11. A toothbrush according to claim 10 characterized in that the elastomer is deformed against its natural resilience, and the resilience of the elastomer in the socket (15) consequently causes the elastomer to grip against the projection and thereby help to retain the pin (14) in the socket (15). 12. A toothbrush according to claim 10 or 11 characterized in that the elastomer material (18) is disposed in one or more cavities in the side wall. 13. A toothbrush according to any one of claims 1 to 4 characterized in that at least part of the socket side wall comprises a resiliently deformable elastomer material which is in shape a convex bulge (28) into the socket (15), so as to narrow the cross section of the socket relative to a deeper part of the socket, and a side surface of the pin (14) has at least one concavity (29) distanced from the end of the pin (14) furthest from the head (12), which, when the pin (14) is inserted into the socket (15) engages with the bulge (28) of the elastomer material (18) in the socket (15). 14. A toothbrush according to claim 13 characterized in that the end of the pin (14) on the side of the concavity remotest from the head (12) hooks behind the bulge (28) of the elastomer. 15. A toothbrush according to any one of the preceding claims characterized in that the socket (15) tapers over at least part of its depth from a wider cross section nearer the opening (16) to a narrower cross section deeper within the socket (15), and the pin (14) tapers correspondingly. 16. A toothbrush according to any one of the preceding claims characterized in that the socket (15) and the pin (14) are of generally corresponding non-circular cross section. 17. A toothbrush according to any one of the preceding claims characterized in that at the longitudinal end of the handle (11) nearest the head (12) is a region of elastomer material (111, 112) which when the head (12) is in place with the pin (14) inserted into the socket (15) abuts against the head (12). 18. A toothbrush according to any one of the preceding claims characterized in that the head (12) and handle (11) are made principally of hard plastic materials, the handle (11) being made of a harder plastic material than the head (12). 19. A toothbrush according to any one of the preceding claims, characterized in that the socket (15) and its side walls (17) comprise a tubular structure (52) extending in the head-handle (12-11) direction of the toothbrush, with the socket (15) comprising the interior of the tube. 20. A toothbrush according to claim 19 characterized in that the end of the handle (11) nearest to the head (12) is in the form of two arms (38) extending toward the head (12), the two arms being on either side of a plane which includes the longitudinal direction and the direction of the bristles, and the tubular structure is supported resiliently between these two arms. 21. A toothbrush according to claim 20 characterized in that the flexible link (39, 53) comprises an integral link between each arm and the tubular structure, which is able to deform torsionally when pressure is applied to the head (12). 22. A replaceable toothbrush head (12) suitable for a toothbrush as claimed in any one of the preceding claims.