Brushing – scrubbing – and general cleaning – Machines – Brushing
Reexamination Certificate
2000-08-28
2002-08-20
Till, Terrence R. (Department: 1744)
Brushing, scrubbing, and general cleaning
Machines
Brushing
C015S028000, C015S029000
Reexamination Certificate
active
06434773
ABSTRACT:
BACKGROUND OF THE INVENTION
It has been recognized through clinical tests that an electrical toothbrush is more effective in removing plaque and preventing gum disease than a conventional manual toothbrush. It is also well known that toothbrush bristles should be replaced on a regular basis since bristle harbor germs after a period of use. While the entire toothbrush can be replaced, it is more economical to replace only the brush elements. In order for an electrical toothbrush to have wide acceptability, the time required to accomplish the brushing operation and the cost required to replace the brush head must be less than that of a manual toothbrush. To obtain the equivalent brushing area of a conventional toothbrush, it is desirable to utilize an electrical toothbrush which has two oscillating brush elements. It is also desirable to replace only the bristle elements and retain the neck portion of the electrical toothbrush for permanent use to minimize replacement costs. And for ease of replacement, it is desirable to have a snap-on feature for self-locating the replaceable bristle elements on the brush head. For the convenience of portability, it is desirable to have a self contained, dentifrice dispensing electrical toothbrush for brushing anywhere at anytime. For the ease of operation of persons with disabilities such as one-handed persons and arthritis sufferers, it is desirable to have a single push-type button to dispense dentifrice material in a controlled quantity and to simultaneously activate a motor which oscillates the brush heads for a pre-determined period of time for brushing. The objects of The objects of this invention are to achieve all of the above desirable features in one electrical toothbrush.
(1) Field of the Invention
The present invention relates to electrical toothbrushes with replaceable brush elements.
(2) Prior Art
It is recognized in the prior art that electrical toothbrushes which have oscillatory brush elements are more effective than toothbrushes with rotating brush heads. The reciprocating movement and wiping action of the bristles provides an effective means for plaque removal. U.S. Pat. No. 4,326,314 by Moret and Jousson describes a means for oscillating a brush head through an oscillating shaft which is connected to a cam riding on a biased wheel mounted on the shaft of a motor. Since the source of vibration is at the cam and the motor which are usually located in the handle, a strong vibration may cause discomfort during brushing.
To minimize the vibration at the handle, U.S. Pat. No. 5,625,916 by McDougall provides a means for converting rotary motion to oscillatory motion near the brush head area which is remote to the motor. It uses a bent remote-most end of a shaft having rotary motion to engage with a slot formed on the side of a bristle holder to force it to oscillate back and forth as the bent remote-most end is driven in a circular annular path. While it achieves relocation of the vibration source to the brush head, the central axis of the bent remote-most end is required to intersect with the central axis of the brush head. This requirement precludes its application for simultaneously driving two brush heads since the same central axis of the remote-most end of a shaft cannot intersect two separate central axes in its circling positions. Also, its use of a closed ended slot on the side of the brush head for engagement also prevents the remote-most end from reaching more than one brush head. Owing to its complex assembly, the entire neck including the brush head, the mounting base and the drive shaft assembly are replaced when the brush head is changed.
U.S. Pat. No. 5,784743 by Shek uses an off-set finger mounted at the end of a rotating shaft for engaging the fork of a pivotally supported wobble plate which is meshed with a gear for oscillating a brush head. The use of the closed end fork and the blocking of the extension of the finger by the pivoting and gear-meshing mechanism prohibit its application to oscillate two brush heads. Similarly, the replacement of the whole neck including the drive shaft is required when the brush head is replaced.
The prior art has also recognized that the brushing area is broadened and the brushing time reduced when two brush heads are used instead of one. For oscillating two brush heads, U.S. Pat. No. 5,353,460 by Bauman uses an oscillating shaft to drive one brush head and utilizes a linkage between the two brush heads to drive the other brush head. The linkage requires a pivoting post on each brush head which adds an increased friction load to the drive mechanism for oscillation of the brush heads. U.S. Pat. No. 5,099,536 by Hirabayashi uses two shafts aligned at different angles. The gearing mechanism allows for driving more than one brush head but its drive mechanism does not cause oscillatory motion. In order to change the brush head, each of the above two patents also requires replacing the neck connected to the brush head which includes part of a drive shaft assembly.
A description of an electrical toothbrush which dispenses liquid is provided in U.S. Pat. No. 5,321,866 by Klupt. The patent discloses a delivery means for a cleaning liquid through oscillating brush heads. A motor is connected to a series of gear mechanisms for causing a drive shaft to oscillate and a piston to pump the liquid through a flow conduit to openings in the brush head. Because it is connected to the same motor, the motorized piston pumps the liquid continuously while the brush heads are oscillating. This common drive mechanism is not desirable for dispensing material that only needs to be dispensed prior to the brushing action.
SUMMARY OF THE INVENTION
This invention provides an electrical toothbrush that satisfies the need for high cleaning efficiency and snap-on replacement parts for easily replacing brushing elements. It also provides a dentifrice dispensing electrical toothbrush that meets a need for simplicity of operation with a single push-button action for both dispensing dentifrice material and energizing a motor for oscillating the brushing elements. The electrical toothbrush of the invention uses a drive mechanism that causes oscillation of two independent brush elements for accomplishing effective cleaning in less time. Rotary motion from a motor is converted to oscillatory motion with either a cam assembly or an off center shaft extension for engaging the drive notches on the brush elements. The brush elements, each of which has plurality of bristles attached to a platform, are mounted on stationary posts on a brush head in a manner that allows them to freely oscillate. They are easily detached and replaced without replacing other components in the drive mechanism. The brush elements are positioned in a retention cradle which facilitates their installation and removal. The retention cradle is detachably positioned on the brush head using a snap-on feature. This feature includes a pair of opposing resilient tabs built on the retention cradle for deflecting a corresponding pair of fastening arms. The fastening arms are lockable on the brush head base and are released by applying an opposing force on the tabs. The resilient tabs are positioned below the bristle surface and are optionally layered with rubber material for protecting gums from excessive brushing pressure.
In dentifrice dispensing toothbrushes, the dual brush elements and the driving mechanism of this invention enable the dispensing of dentifrice material to one of the brush elements which distributes the dentifrice material to all brushing areas during brushing action. The delivery of the dentifrice material is achieved by using a toothbrush neck having two separated channels. One channel houses the drive shaft and the other channel functions as part of the flow path for the dentifrice material as it is pumped from the handle to the brush head. The pumping mechanism includes a refillable cartridge, a one-way valve, a pumping chamber and a resilient compressible button for applying pressure to force dentifrice material from the chamber to
Denson Fred L.
Till Terrence R.
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