Toothbrush employing resiliently buckling arch to indicate excessive brushing pressure

• US 5,146,645 A
• Filed: 03/01/1991
• Issued: 09/15/1992
• Est. Priority Date: 03/01/1991
• Status: Expired due to Fees

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Dirksing, Robert S.
• Primary Examiner(s): Coe, Philip R.
• Assistant Examiner(s): Till, Terrence R.
• Application Number:
  US07/663,214
• Time in Patent Office: 564 Days
• Field of Search: 15/167.1, 15/167.2, 15/143 R, 15/172
• US Class Current: 15/167.1
• CPC Class Codes: A46B 2200/1066 Toothbrush for cleaning the teeth or dentures A61C17/16 takes precedence; bristles arrangements for toothbrushes A46B9/04
• CPC Class Codes: A46B 5/0062 being flexible or resilient during use
• CPC Class Codes: A46B 5/0066 Flexible resilience by elastic deformation of the material

Abstract

A toothbrush employing a force indicator which visually and tactually signals the user that a predetermined brushing force has been exceeded. The force indicator is comprised of a resilient twin beam structure located between the toothbrush handle and the toothbrush head which includes a scrubbing or polishing medium, typically bristles. The twin beam structure is itself comprised of a back side beam and a face side beam. During normal use, the back side beam is subjected to compressive stress whereas the face side beam is subjected to tensile stress. The at rest configuration of the back side beam permits it to behave as an upwardly convex arch upon initial application of compressive force resulting from a user gripping the handle and bringing the bristles or other cleansing or scrubbing medium in contact with the teeth and gums. When a predetermined force is exceeded, the back side beam resiliently buckles and inverts to a downwardly convex arch configuration. In a preferred embodiment, the back side and face side beams are nonparallel with a convergent taper from the brush handle in the direction of the brush head. The disclosed twin beam structures resist deflection up to a predetermined force which is determined primarily by their material properties and their precise geometric configuration. Attempting to exceed the predetermined force which the toothbrush is capable of transmitting by applying additional manual force to the brush handle results in resilient buckling of the back side beam in the twin beam structure, followed by substantial deflection of the brush head relative to the brush handle without a corresponding increase in the force applied to the teeth and gum tissue via the bristles on the brush head.

Claims

1. A toothbrush comprising a handle having a face side and a back side opposite said face side and a brush head having a face side which carries a cleansing medium for cleaning the user'"'"'s teeth and gums and a back side opposite said face side, said toothbrush further including a force indicator which simultaneously visually and tactually signals the user when a predetermined brushing force is exceeded, said force indicator comprising a resilient twin beam structure having a first end connected to said brush handle and a second end connected to said brush head, said resilient twin beam structure comprising a face side beam extending between said face side of said handle and said face side of said brush head and a back side beam extending between and substantially rigidly connected to said back side of said handle and said back side of said brush head, said back side beam exhibiting an arched at rest configuration including a point of formed weakness intermediate said first end and said second end of said resilient twin beam structure which will permit said back side beam to behave as an upwardly convex arch when said back side beam is initially subjected to compressive stress and said face side beam is initially subjected to tensile stress resulting from the user gripping said handle and bringing the cleansing medium on said brush head in contact with their teeth and gums, the predetermined force which may be exerted on the user'"'"'s teeth and gums being limited by the maximum compressive force which said back side beam can resist before it ceases to function as an upwardly convex arch and undergoes temporary and resilient buckling and deformation sufficient to cause it to invert to a downwardly convex configuration, thereby providing a simultaneous visual and tactile signal to the brush user that a predetermined brushing force has been exceeded.

6. The toothbrush of claim 1 or claim 2, wherein said face side beam exhibits a substantially uniform cross-section substantially throughout its length.

7. The toothbrush of claim 1 or claim 2, wherein said face side beam contains a point of formed weakness intermediate said first end and said second end of said resilient twin beam structure.

8. The toothbrush of claim 7, wherein said point of formed weakness in said face side beam comprises a hinge.

2. A toothbrush comprising a handle having a face side and a back side opposite said face side and a brush head having a face side which carries bristles for cleaning the user'"'"'s teeth and gums and a back side opposite said face side, said toothbrush further including a force indicator which simultaneously visually and tactually signals the user when a predetermined brushing force is exceeded, said force indicator comprising a resilient twin beam structure having a first end connected to said brush handle and a second end connected to said brush head, said resilient twin beam structure comprising a face side beam extending between said face side of said handle and said face side of said brush head and a back side beam extending between and substantially rigidly connected to said back side of said handle and said back side of said brush head, said back side beam including in its at rest configuration a point of formed weakness intermediate said first end and said second end of said resilient twin beam structure which will permit said back side beam to behave as an upwardly convex arch when said back side beam is initially subjected to compressive stress and said face side beam is initially subjected to tensile stress resulting from the user gripping said handle and bringing the bristles on said brush head in contact with their teeth and gums, the predetermined force may be exerted on the user'"'"'s teeth and gums being limited by the maximum compressive force which said back side beam can resist before it ceases to function as an upwardly convex arch and undergoes temporary and resilient buckling and deformation sufficient to cause it to invert to a downwardly convex configuration, thereby providing a simultaneous visual and tactile signal to the brush user that a predetermined brushing force has been exceeded.

3. The toothbrush of claim 2, wherein said back side beam tapers in cross=section from said first end to said point of formed weakness.

4. The toothbrush of claim 2, wherein said point of formed weakness in said back side beam comprises an incremental step to a smaller cross-section.

5. The toothbrush of claim 2, wherein said point of formed weakness in said back side beam comprises a hinge.

9. A toothbrush comprising a handle having a face side and a back side opposite said face side and a brush head having a face side which carries a cleansing medium for cleaning the user'"'"'s teeth and gums and a back side opposite said face side, said toothbrush further including a force indicator which simultaneously visually and tactually signals the user when a predetermined brushing force is exceeded, said force indicator comprising a resilient twin beam structure having a first end connected to said brush handle and a second end connected to said brush head, said resilient twin beam structure comprising a face side beam extending between said face side of said handle and said face side of said brush head and a back side beam extending between and substantially rigidly connected to said back side of said handle and said back side of said brush head, wherein said back side beam convergently tapers from said first end in the direction of said second end relative to said face side beam to form an acute angle therebetween, said back side beam exhibiting an arched at rest configuration including a point of formed weakness intermediate said first end and said second end of said resilient twin beam structure which will permit said back side beam to behave as an upwardly convex arch when said back side beam is initially subjected to compressive forces and said face side beam is initially subjected to tensile forces resulting from the user gripping said handle and bringing the cleansing medium on said brush head in contact with their teeth and gums, the predetermined force which may be exerted on the user'"'"'s teeth and gums being limited by the maximum compressive force which said back side beam can resist before it ceases to function as an upwardly convex arch and undergoes temporary and resilient buckling and deformation sufficient to cause it to invert to a downwardly convex configuration, thereby providing a simultaneous visual and tactile signal to the brush user that a predetermined brushing force has been exceeded.

10. A toothbrush comprising a handle having a face side and a back side opposite said face side an brush head having a face side which carries bristles for cleaning the user'"'"'s teeth and gums and a back side opposite said face side, said toothbrush further including a force indicator which simultaneously visually and tactually signals the user when a predetermined brushing force is exceeded, said force indicator comprising a resilient twin beam structure having a first end connected to said brush handle and a second end connected to said brush head, said resilient twin beam structure comprising a face side beam extending between said face side of said handle and said face side of said brush head and a back side beam extending between and substantially rigidly connected to said back side of said handle and said back side of said brush head, wherein said back side beam convergently tapers from aid first end in the direction of said second end relative to said face side beam to form an acute angle therebetween, said back side beam including in its at rest configuration a point of formed weakness intermediate said first end and said second end of said resilient twin beam structure which will permit said back side beam to behave as an upwardly convex arch when said back side beam is initially subjected to compressive forces and said face side beam is initially subjected to tensile forces resulting from the user gripping said handle and bringing the bristles on said brush head in contact with their teeth and gums, the predetermined force which may be exerted on the user'"'"'s teeth and gums being limited by the maximum compressive force which said back side beam can resist before it ceases to function as an upwardly convex arch and undergoes temporary and resilient buckling and deformation sufficient to cause it to invert to a downwardly convex configuration, thereby providing a simultaneous visual and tactile signal to the brush user that a predetermined brushing force has been exceeded.

11. The toothbrush of claim 10, wherein said back side beam tapers in cross-section from said first end to said point of formed weakness.

12. The toothbrush of claim 10, wherein said point of formed weakness in said back side beam comprises an incremental step to a smaller cross-section.

13. The toothbrush of claim 10, wherein said point of formed weakness in said back side beam comprises a hinge.

14. The toothbrush of claim 9 or claim 10, wherein said face side beam contains a point of formed weakness intermediate said first end and said second end of said resilient twin beam structure.

15. The toothbrush of claim 14, wherein said point of formed weakness in said face side beam comprises a hinge.