CA1268011A - Electrical toothbrush - Google Patents
Electrical toothbrushInfo
- Publication number
- CA1268011A CA1268011A CA000489165A CA489165A CA1268011A CA 1268011 A CA1268011 A CA 1268011A CA 000489165 A CA000489165 A CA 000489165A CA 489165 A CA489165 A CA 489165A CA 1268011 A CA1268011 A CA 1268011A
- Authority
- CA
- Canada
- Prior art keywords
- cleaning element
- toothbrush according
- element structure
- toothbrush
- cleaning head
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
- A61C17/00—Devices for cleaning, polishing, rinsing or drying teeth, teeth cavities or prostheses; Saliva removers; Dental appliances for receiving spittle
- A61C17/16—Power-driven cleaning or polishing devices
- A61C17/22—Power-driven cleaning or polishing devices with brushes, cushions, cups, or the like
- A61C17/222—Brush body details, e.g. the shape thereof or connection to handle
-
- A—HUMAN NECESSITIES
- A46—BRUSHWARE
- A46B—BRUSHES
- A46B5/00—Brush bodies; Handles integral with brushware
- A46B5/002—Brush bodies; Handles integral with brushware having articulations, joints or flexible portions
- A46B5/0054—Brush bodies; Handles integral with brushware having articulations, joints or flexible portions designed to allow relative positioning of the head to body
- A46B5/0062—Brush bodies; Handles integral with brushware having articulations, joints or flexible portions designed to allow relative positioning of the head to body being flexible or resilient during use
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
- A61C17/00—Devices for cleaning, polishing, rinsing or drying teeth, teeth cavities or prostheses; Saliva removers; Dental appliances for receiving spittle
- A61C17/16—Power-driven cleaning or polishing devices
- A61C17/22—Power-driven cleaning or polishing devices with brushes, cushions, cups, or the like
- A61C17/24—Power-driven cleaning or polishing devices with brushes, cushions, cups, or the like rotating continuously
-
- A—HUMAN NECESSITIES
- A46—BRUSHWARE
- A46B—BRUSHES
- A46B2200/00—Brushes characterized by their functions, uses or applications
- A46B2200/10—For human or animal care
- A46B2200/1066—Toothbrush for cleaning the teeth or dentures
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/42—Brushes
- B29L2031/425—Toothbrush
Landscapes
- Health & Medical Sciences (AREA)
- Dentistry (AREA)
- Epidemiology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Brushes (AREA)
Abstract
Abstract The invention relates to an electric toothbrush, consisting of a handle, with a drive mounted inside it, to which a brush shaft (1) is releasably fastened by its end opposite the brush head, the brush head describing a circular motion whose rotational axis (4) runs radially to brush shaft (1) and the brush head is tiltably mounted.
(Figure 2)
(Figure 2)
Description
o~
The invention relates to an electric toothbrush of the type having a drive mounted in the handle and a cleaning element supported by the handle.
An electric toothbrush is known from the PCT
application W084/02453 (published July 5, 1984 in the name of Rosenstatter~, comprising a handle with a drive and a brush shaft. A bristle head is formed on the brush shaft, said head being mounted so as to be rotatable about a rotational axis directed perpendicularly to the brush shaft. The disadvantage of the known toothbrush is that the bristle head can penetrate the spaces between the teeth only with difficulty.
In addition, a toothbrush is known from German OS 29 28 449 whose brush head is connected with the shaft of the toothbrush by a coil spring. The brush head can execute twisting and tilting movements during the tooth cleaning process by means of the coil spring suspension. Admittedly, the bristle edges of known toothbrushes permit penetration of the spaces between the teeth because the tooth cleaning head can tilt to match the contours of the surfaces of the teeth, but the defect of these toothbrushes lies in the fact that the cleaning motion provided by the continuous rotation of the tooth cleaning head is not present. In other words, the bristle head according to German OS 29 28 449 cannot rotate fully and continuously.
In addition, a toothbrush is known from EP-A2 66 259 which comprises a bristle head which is tiltably mounted like a rocker. The rotational axis of the bristle head in this toothbrush runs transversely to the lengthwise axis of the brush. The brush head ~ q rn/j~
i~ :
~L2~
can tilt forward and backward during the horizontal polishing movement~ becauce of the rocker mounting, thereby slightly penetrating the spaces between the teeth. In -this toothbru~3h too, there is no rotary polishing motion.
I,ike the toothbrush according to EP-A2 66 259, a toothbrush is known from EP-Bl 23 407 and FR-AS 25 50 068 which has its brush head rotatably mounted on an axis perpendicular to the lengthwise axis of the toothbrush. The toothbrush according to FR-AS 25 50 068 in addition comprises a spring rod which aligns the 10 bruæh head in a preferred basic position. In the two last mentioned toothbrushes as well, the rotary polishing motion is likewise not provided, The goal of the invention therefore is to provide an electric toothbrush whose bristle head offers a considerable cleaning action on all curved parts of the tooth surfaces, gingival pockets, gingival furroNs, and the spaces between the teeth.
The invention relates to an electric toothbrush comprising a heandle and a tooth cleaning head. The tooth cleaning head has a body and cleaning element structure mounted in annular array on the 20 body. A drive i~ provided in the handle for driving the tooth cleaning head in rotation about a rotational axis generally coaxial with the cleaning element structure, and an articulation structure is coupled between the drive and the cleaning element structure, the articulation structure being disposed adjacent the center OI gravity of the tooth cleaning head and permitting tilting movement of the cleaning element structure relative to the body as the tooth kh/J~
~ `
cleaning head is driven in rotation about its rotational axis by the drive.
Thu3, the invention provides an electric toothbrush with a bristle or brush head or a tooth clsaning head i9 provided, comprising an articulated device which, in addition to complete and continuou~ rotary motion of the cleaning head, also permit~ tilting out of the basic position. In other words, in addition to the rotary motion, the cleaning head has additional degrees of freedom.
Depending on the design of the articulation device, one or two additional degree~ of freedom are provided, 90 that the cleaning head can readily adjust to all the - 2a -kh~c ~' contours and spaces between the teeth automatically during the polishing motions. Thus, the cleaning head, running at top speed, is pivotable relative to the lengthwise axis without the toothbrush or its lengthwise axis having to adopt a different directional orientation.
When the toothbrush with the tooth cleaning head according to the invention is guided along the rows of teeth, the leading edge of the cleaning element, for example in the form of a crown of bristles or rubber cups, automatically pivots into the adjoining spaces between the teeth because the force with which the cleaning head against the necks of the teeth evokes forces acting from the outside which cause the bristle crown by lever action to pivot into the spaces between the teeth. In other words, the position of the cleaning head adapts itself from a basic working position to the different curvatures of the tooth surfaces. Qs a result OI the improved mobility of the cleaning head, the cleaning action in addition to the considerable polishing effect caused by the continuous rotation of the head, is considerably increased.
The articulation device can be provided between the rotational axis and the tooth cleaning head, with the rotational axis being permanently located on the lengthwise axis of the toothbrush in this c~se.
Otherwise, it is possible to provide the articulation device between the lengthwise axis and the rotational axis and to mount the cleaning head preferably rigidly on the rotational axis. In all cases, the same advantageous tilting action is achieved, i.e~ all of the embodiments of the articulation arrangement lie within the scope of the invention, in which the cleaning head itself or together with the rotational axis can -4~
be tilted through a certain range of angles out of its basic working position. The tooth cleaning head or the brush head is there~ore mounted in such fashion that it is pivotable under inhomogeneous external force application up to a maximum angle of approximately 20 to 30. As a result, considerably improved cleaning of the teeth is achieved without requiring additional effort on the part of the user.
As a fre~uency range for the circular motion with which the brush head is rotated, 5 to 50 Hz, especially however 7 to 10 Hz, is proposed. At a higher frequency, the bristles harden more rapidly and the brush head is no longer in a position at high speeds to adapt sufficiently to the contours of the teeth. At lower frequencies, on the other hand, the drive becomes irregular and tends to generate imbalances.
In an especially preferred embodiment, the brush head is a crown plate rotating about its axis of symmetry. The term "crown plate" within the scope of the invention defines a plate-shaped structure on which a crown consisting of cleaning means or cleaning elements is mounted, with cleaning means being understood to mean, in addition to bristles, the rubber cups, described in greater detail hereinbelow. It is characteristic of this embodiment that the crown plate rotate about its axis of symmetry, in other words it retains its center of gravity, and the circular motion is accomplished through its own rotation.
In particular, outwardly pointing bristles can be mounted vertically or diagonally on the plate9 whereby in the latter case a greater effective area is produced ~or the same plate diameter. According to another O~
recommendation of the invention, the crown plate is free of bristles in the vicinity of the rotational axis if it is not desirable for the central bristle areas to collect and concentrate in the spaces between the teeth during rotation. As the bristle head is pressed against the teeth9 the outer bristles bend outward and the inner bristles penetrate more deeply into the spaces between the teeth. If a bristle head completely covered with bristles is employed, the inner bristles ser~re primarily to clean the spaces between the teeth while the outer bristles act on the gingival margin. On the other hand, the bristle-free central area creates the opportunity to apply the toothpaste in the area of the crown plate which is in the vicinity of the rotational axis, said toothpaste being uniformly distributed into the peripheral zones during operation, i.e. during rotation of the crown plate.
In another feasible version of the crown plate, a frustroconical jacket which opens outward is mounted on the plate, which also consists of an elastic material, rubber for example. Experience indicates that such '1rubber cups" produce better cleaning than heads designed with bristles. The opening in the cup can be used to hold toothpaste, with the latter being uniformly spread over the teeth and forced into the spaces between the teeth by the pressure exerted during operation, which results in a spreading of the frustroconical jacket because of its elasticity. A further improvement to this crown plate consists in closing the outwardly open frustroconical jacket with a membrane on which bristles are mounted. The membrane can change its shape and structure by virtue of its intrinsic elasticity and adapt in this way to the surfaces of the teeth or the spaces between the teeth. In addition, -6- ~aZ~
, the eïasticity of the rubber cup supporting the membrane allows the opening width to be varied as a function of application pressure, so that the proposed embodiment combines both the advantages of the rubber cup with those of a crown plate fitted with bristles.
In addition, when a crown plate is used, a frequency of 5 to 50 Hz is proposed, whereby the best cleaning results can be achieved in the 2 to 15 Hz range for the reasons set forth above. Extending the frequency range downward is based on the fact that when a crown plate is used the center of gravity remains fixed in space even during the operating phase and the resultant imbalances are therefore much less than when the brush head moves in a circular fashion.
The gingival margin which defines the transition between the tooth and the gum is a curved line whose midpoint corresponds roughly to a circle with a diameter of approximately 1.5 cm. The best possible cleaning of this area can therefore be achieved if the circular motions of the brush head is so dimensioned that it describes a circle with a diameter of 1.5 cm because then the bristles move essentially along the gingival margin and clean the latter optimally.
In a preferred embodiment, it is proposed to subject the teeth to a cleaning process from both sides, i. e. from inside and outside simultaneously, with two brush heads being applied, located some distance apart and facing one another, whereby the space between them is made smaller than the average thickness of the teeth. The bristle heads of the toothbrush can then be mounted in the form of a forked -7- ~ Ol~L
, head. One of the essential advantages is that all the teeth can be cleaned in approximately h~lf the time.
According to one advantageous embodiment, a spring element is provided which moves the cleaning head back into the basic operating position after the external action of force on the cleaning elements is removed. The user therefore can advantageously predict the position of the cleaning surface after removing the cleaning head from the teeth and can readily position the cleaning head directly at a new point, The cleaning head therefore does not execute any uncontrolled movements when the cleaning elements are not in contact with the teeth. The spring constant of the spring element is so dimensioned that the cleaning head assumes a specific position in the freely rotating state and, moreover~ the tilting movements are not impeded as it moves over the surface of the teeth.
The invention is described hereinbelow in greater detail with reference to the drawing.
Figure 1 is a side view of a crown plate fastened to a brush shaft;
Figure 2 is the top view of the embodiment shown in Figure l;
Figure 3 is a tooth cleaning head according to the invention with a cross ball joint;
-8- ~~
,, ~
Figure 4 is a section along line AB in the support for the cleaning elements of the tooth cleaning head in Figure 1;
Figure 5 is a lengthw~se section through a brush haad of a toothbrush;
Figures 6A, 6B, and 6C are embodiments of leaf springs; and Figure 7 is a lengthwise s~ction through another embodiment of the tooth cleaning head according to the invention.
Only the forward part of brush handle 44 is shown in the electric toothbrush in Figure 1, on which shaft the brush head or crown plate, marked tooth cleaning head 1, is rotatably mounted, with its rotational axis 3 running radially to brush shaft 1. During each phase of its motion, crown plate 1 remains in the same plane running tangentially to the covering of brush shaft 44. After the drive is switched on, crown plate 1 is set rotating by means of power transmission means not shown here. Cleaning elements 10, e . g. bristles, are mounted approximately vertically on its surface, in such fashion that an area around rotational axis 3 is left free.
The toothbrush according to the invention is used in such fashion that before or after the drqve is switched on, crown plate 1 is applied with light pressure against the teeth and gums by means of bristles 10, possibly after applving toothpaste, especially in the ~icinity of rotational axis 3, and then moved back and forth by means of brush -9- ~2~
shaft 44. The gingival margin is cleaned especially thoroughly when the circles described by bristles 10 have an average diameter of approximately 1. 5 cm, since in this case the motion occurs essentially along the gingival margin. A value of 2-15 Hz is proposed as especially favorable for the rotational frequency.
Figure 2 is the same embodim~nt viewed from above. Crown plate 1 is provided with bristles 10 on one side (the lower side) and connected on its opposite side by means of a rotational axis 3 with brush shaft 44 in such fashion that crown plate l in its totality can tilt about an axis perpendicular to brush shaft 44 and rotational axis 3. For clarity's sake, a crown plate 1 in the tilted position is showrl by the dashed lines. It is critical to the invention that, on the one hand, connection with the drive of the toothbrush is provided even during pivoting, i.e.
in every possible position, and, on the other hand, that the pivoting motion be evoked by nonuniform application of force to the surface of crown plate 1. During practical application it occurs as a rule that crown plate 1 partially rests against a tooth and spans a space whereby it is subjected to an asymmetric, i . e. inhomogeneous outer force, causing crown plate 1 to pivot, in such fashion that the part which is in the vicinity of the tooth is moved toward brush shaft 44 and ths other part consequently moves away from it. As a result, crown plate l and the bristles 10 located thereon can penetrate the spaces between the teeth better and clean them. lNhen the force application just described is terminated, the crown plate returns to its original position The result is an electric toothbrush which permits much more thorough and more complete cleaning of the teeth while simultaneously avoiding injury to the g~um.
Figure 3 shows an embodiment of a tooth cleaning head 1 of a toothbrush with an articulation device which comprises a cross ball joint. The cross ball joint consists of a ball shell 5, a ball joint 4, pins 6, and annular groove 7. Rotational axis 3 is provided on ball joint 4, which sets tooth cleaning head 1 rotating . B all shell S is machined into a support 2, as for example crown plate 2 described above, said support as shown in Figure 3 having bristles 10 in the form of a bristle crown thereon. In order to prevent ball joint 4 from penetrating ball shell 5 as a result of rotation of rotational axis 3, the pins 6 located opposite one another are provided. Pins 6 slide in annular groove 7, so that, based on Figure 1 as shown, rotational axis 3 can make movements to the left and right9 as well as in snd out of the plane of the drawing. The articulaffon device in the simplest case can also be designed as a pin joint, permitting one degree of freedom.
Figure 4 is a section through support 2 along line AB, and Figures 3 and 4 are intended to show that the articulation device shown can be moved in the directions indicated. In other words, the articulation device has two degrees of freedom, but tooth cleaning head 1 can nevertheless be set rotating by means of pins 6. Power transmission then occurs from rotational axis 3 to pins 6, which in turn transfer the forces to the side walls of annular grooves 7. Aperture cone 8 is cut out at the point of entry of rotational axis 3 into support 2, so that
The invention relates to an electric toothbrush of the type having a drive mounted in the handle and a cleaning element supported by the handle.
An electric toothbrush is known from the PCT
application W084/02453 (published July 5, 1984 in the name of Rosenstatter~, comprising a handle with a drive and a brush shaft. A bristle head is formed on the brush shaft, said head being mounted so as to be rotatable about a rotational axis directed perpendicularly to the brush shaft. The disadvantage of the known toothbrush is that the bristle head can penetrate the spaces between the teeth only with difficulty.
In addition, a toothbrush is known from German OS 29 28 449 whose brush head is connected with the shaft of the toothbrush by a coil spring. The brush head can execute twisting and tilting movements during the tooth cleaning process by means of the coil spring suspension. Admittedly, the bristle edges of known toothbrushes permit penetration of the spaces between the teeth because the tooth cleaning head can tilt to match the contours of the surfaces of the teeth, but the defect of these toothbrushes lies in the fact that the cleaning motion provided by the continuous rotation of the tooth cleaning head is not present. In other words, the bristle head according to German OS 29 28 449 cannot rotate fully and continuously.
In addition, a toothbrush is known from EP-A2 66 259 which comprises a bristle head which is tiltably mounted like a rocker. The rotational axis of the bristle head in this toothbrush runs transversely to the lengthwise axis of the brush. The brush head ~ q rn/j~
i~ :
~L2~
can tilt forward and backward during the horizontal polishing movement~ becauce of the rocker mounting, thereby slightly penetrating the spaces between the teeth. In -this toothbru~3h too, there is no rotary polishing motion.
I,ike the toothbrush according to EP-A2 66 259, a toothbrush is known from EP-Bl 23 407 and FR-AS 25 50 068 which has its brush head rotatably mounted on an axis perpendicular to the lengthwise axis of the toothbrush. The toothbrush according to FR-AS 25 50 068 in addition comprises a spring rod which aligns the 10 bruæh head in a preferred basic position. In the two last mentioned toothbrushes as well, the rotary polishing motion is likewise not provided, The goal of the invention therefore is to provide an electric toothbrush whose bristle head offers a considerable cleaning action on all curved parts of the tooth surfaces, gingival pockets, gingival furroNs, and the spaces between the teeth.
The invention relates to an electric toothbrush comprising a heandle and a tooth cleaning head. The tooth cleaning head has a body and cleaning element structure mounted in annular array on the 20 body. A drive i~ provided in the handle for driving the tooth cleaning head in rotation about a rotational axis generally coaxial with the cleaning element structure, and an articulation structure is coupled between the drive and the cleaning element structure, the articulation structure being disposed adjacent the center OI gravity of the tooth cleaning head and permitting tilting movement of the cleaning element structure relative to the body as the tooth kh/J~
~ `
cleaning head is driven in rotation about its rotational axis by the drive.
Thu3, the invention provides an electric toothbrush with a bristle or brush head or a tooth clsaning head i9 provided, comprising an articulated device which, in addition to complete and continuou~ rotary motion of the cleaning head, also permit~ tilting out of the basic position. In other words, in addition to the rotary motion, the cleaning head has additional degrees of freedom.
Depending on the design of the articulation device, one or two additional degree~ of freedom are provided, 90 that the cleaning head can readily adjust to all the - 2a -kh~c ~' contours and spaces between the teeth automatically during the polishing motions. Thus, the cleaning head, running at top speed, is pivotable relative to the lengthwise axis without the toothbrush or its lengthwise axis having to adopt a different directional orientation.
When the toothbrush with the tooth cleaning head according to the invention is guided along the rows of teeth, the leading edge of the cleaning element, for example in the form of a crown of bristles or rubber cups, automatically pivots into the adjoining spaces between the teeth because the force with which the cleaning head against the necks of the teeth evokes forces acting from the outside which cause the bristle crown by lever action to pivot into the spaces between the teeth. In other words, the position of the cleaning head adapts itself from a basic working position to the different curvatures of the tooth surfaces. Qs a result OI the improved mobility of the cleaning head, the cleaning action in addition to the considerable polishing effect caused by the continuous rotation of the head, is considerably increased.
The articulation device can be provided between the rotational axis and the tooth cleaning head, with the rotational axis being permanently located on the lengthwise axis of the toothbrush in this c~se.
Otherwise, it is possible to provide the articulation device between the lengthwise axis and the rotational axis and to mount the cleaning head preferably rigidly on the rotational axis. In all cases, the same advantageous tilting action is achieved, i.e~ all of the embodiments of the articulation arrangement lie within the scope of the invention, in which the cleaning head itself or together with the rotational axis can -4~
be tilted through a certain range of angles out of its basic working position. The tooth cleaning head or the brush head is there~ore mounted in such fashion that it is pivotable under inhomogeneous external force application up to a maximum angle of approximately 20 to 30. As a result, considerably improved cleaning of the teeth is achieved without requiring additional effort on the part of the user.
As a fre~uency range for the circular motion with which the brush head is rotated, 5 to 50 Hz, especially however 7 to 10 Hz, is proposed. At a higher frequency, the bristles harden more rapidly and the brush head is no longer in a position at high speeds to adapt sufficiently to the contours of the teeth. At lower frequencies, on the other hand, the drive becomes irregular and tends to generate imbalances.
In an especially preferred embodiment, the brush head is a crown plate rotating about its axis of symmetry. The term "crown plate" within the scope of the invention defines a plate-shaped structure on which a crown consisting of cleaning means or cleaning elements is mounted, with cleaning means being understood to mean, in addition to bristles, the rubber cups, described in greater detail hereinbelow. It is characteristic of this embodiment that the crown plate rotate about its axis of symmetry, in other words it retains its center of gravity, and the circular motion is accomplished through its own rotation.
In particular, outwardly pointing bristles can be mounted vertically or diagonally on the plate9 whereby in the latter case a greater effective area is produced ~or the same plate diameter. According to another O~
recommendation of the invention, the crown plate is free of bristles in the vicinity of the rotational axis if it is not desirable for the central bristle areas to collect and concentrate in the spaces between the teeth during rotation. As the bristle head is pressed against the teeth9 the outer bristles bend outward and the inner bristles penetrate more deeply into the spaces between the teeth. If a bristle head completely covered with bristles is employed, the inner bristles ser~re primarily to clean the spaces between the teeth while the outer bristles act on the gingival margin. On the other hand, the bristle-free central area creates the opportunity to apply the toothpaste in the area of the crown plate which is in the vicinity of the rotational axis, said toothpaste being uniformly distributed into the peripheral zones during operation, i.e. during rotation of the crown plate.
In another feasible version of the crown plate, a frustroconical jacket which opens outward is mounted on the plate, which also consists of an elastic material, rubber for example. Experience indicates that such '1rubber cups" produce better cleaning than heads designed with bristles. The opening in the cup can be used to hold toothpaste, with the latter being uniformly spread over the teeth and forced into the spaces between the teeth by the pressure exerted during operation, which results in a spreading of the frustroconical jacket because of its elasticity. A further improvement to this crown plate consists in closing the outwardly open frustroconical jacket with a membrane on which bristles are mounted. The membrane can change its shape and structure by virtue of its intrinsic elasticity and adapt in this way to the surfaces of the teeth or the spaces between the teeth. In addition, -6- ~aZ~
, the eïasticity of the rubber cup supporting the membrane allows the opening width to be varied as a function of application pressure, so that the proposed embodiment combines both the advantages of the rubber cup with those of a crown plate fitted with bristles.
In addition, when a crown plate is used, a frequency of 5 to 50 Hz is proposed, whereby the best cleaning results can be achieved in the 2 to 15 Hz range for the reasons set forth above. Extending the frequency range downward is based on the fact that when a crown plate is used the center of gravity remains fixed in space even during the operating phase and the resultant imbalances are therefore much less than when the brush head moves in a circular fashion.
The gingival margin which defines the transition between the tooth and the gum is a curved line whose midpoint corresponds roughly to a circle with a diameter of approximately 1.5 cm. The best possible cleaning of this area can therefore be achieved if the circular motions of the brush head is so dimensioned that it describes a circle with a diameter of 1.5 cm because then the bristles move essentially along the gingival margin and clean the latter optimally.
In a preferred embodiment, it is proposed to subject the teeth to a cleaning process from both sides, i. e. from inside and outside simultaneously, with two brush heads being applied, located some distance apart and facing one another, whereby the space between them is made smaller than the average thickness of the teeth. The bristle heads of the toothbrush can then be mounted in the form of a forked -7- ~ Ol~L
, head. One of the essential advantages is that all the teeth can be cleaned in approximately h~lf the time.
According to one advantageous embodiment, a spring element is provided which moves the cleaning head back into the basic operating position after the external action of force on the cleaning elements is removed. The user therefore can advantageously predict the position of the cleaning surface after removing the cleaning head from the teeth and can readily position the cleaning head directly at a new point, The cleaning head therefore does not execute any uncontrolled movements when the cleaning elements are not in contact with the teeth. The spring constant of the spring element is so dimensioned that the cleaning head assumes a specific position in the freely rotating state and, moreover~ the tilting movements are not impeded as it moves over the surface of the teeth.
The invention is described hereinbelow in greater detail with reference to the drawing.
Figure 1 is a side view of a crown plate fastened to a brush shaft;
Figure 2 is the top view of the embodiment shown in Figure l;
Figure 3 is a tooth cleaning head according to the invention with a cross ball joint;
-8- ~~
,, ~
Figure 4 is a section along line AB in the support for the cleaning elements of the tooth cleaning head in Figure 1;
Figure 5 is a lengthw~se section through a brush haad of a toothbrush;
Figures 6A, 6B, and 6C are embodiments of leaf springs; and Figure 7 is a lengthwise s~ction through another embodiment of the tooth cleaning head according to the invention.
Only the forward part of brush handle 44 is shown in the electric toothbrush in Figure 1, on which shaft the brush head or crown plate, marked tooth cleaning head 1, is rotatably mounted, with its rotational axis 3 running radially to brush shaft 1. During each phase of its motion, crown plate 1 remains in the same plane running tangentially to the covering of brush shaft 44. After the drive is switched on, crown plate 1 is set rotating by means of power transmission means not shown here. Cleaning elements 10, e . g. bristles, are mounted approximately vertically on its surface, in such fashion that an area around rotational axis 3 is left free.
The toothbrush according to the invention is used in such fashion that before or after the drqve is switched on, crown plate 1 is applied with light pressure against the teeth and gums by means of bristles 10, possibly after applving toothpaste, especially in the ~icinity of rotational axis 3, and then moved back and forth by means of brush -9- ~2~
shaft 44. The gingival margin is cleaned especially thoroughly when the circles described by bristles 10 have an average diameter of approximately 1. 5 cm, since in this case the motion occurs essentially along the gingival margin. A value of 2-15 Hz is proposed as especially favorable for the rotational frequency.
Figure 2 is the same embodim~nt viewed from above. Crown plate 1 is provided with bristles 10 on one side (the lower side) and connected on its opposite side by means of a rotational axis 3 with brush shaft 44 in such fashion that crown plate l in its totality can tilt about an axis perpendicular to brush shaft 44 and rotational axis 3. For clarity's sake, a crown plate 1 in the tilted position is showrl by the dashed lines. It is critical to the invention that, on the one hand, connection with the drive of the toothbrush is provided even during pivoting, i.e.
in every possible position, and, on the other hand, that the pivoting motion be evoked by nonuniform application of force to the surface of crown plate 1. During practical application it occurs as a rule that crown plate 1 partially rests against a tooth and spans a space whereby it is subjected to an asymmetric, i . e. inhomogeneous outer force, causing crown plate 1 to pivot, in such fashion that the part which is in the vicinity of the tooth is moved toward brush shaft 44 and ths other part consequently moves away from it. As a result, crown plate l and the bristles 10 located thereon can penetrate the spaces between the teeth better and clean them. lNhen the force application just described is terminated, the crown plate returns to its original position The result is an electric toothbrush which permits much more thorough and more complete cleaning of the teeth while simultaneously avoiding injury to the g~um.
Figure 3 shows an embodiment of a tooth cleaning head 1 of a toothbrush with an articulation device which comprises a cross ball joint. The cross ball joint consists of a ball shell 5, a ball joint 4, pins 6, and annular groove 7. Rotational axis 3 is provided on ball joint 4, which sets tooth cleaning head 1 rotating . B all shell S is machined into a support 2, as for example crown plate 2 described above, said support as shown in Figure 3 having bristles 10 in the form of a bristle crown thereon. In order to prevent ball joint 4 from penetrating ball shell 5 as a result of rotation of rotational axis 3, the pins 6 located opposite one another are provided. Pins 6 slide in annular groove 7, so that, based on Figure 1 as shown, rotational axis 3 can make movements to the left and right9 as well as in snd out of the plane of the drawing. The articulaffon device in the simplest case can also be designed as a pin joint, permitting one degree of freedom.
Figure 4 is a section through support 2 along line AB, and Figures 3 and 4 are intended to show that the articulation device shown can be moved in the directions indicated. In other words, the articulation device has two degrees of freedom, but tooth cleaning head 1 can nevertheless be set rotating by means of pins 6. Power transmission then occurs from rotational axis 3 to pins 6, which in turn transfer the forces to the side walls of annular grooves 7. Aperture cone 8 is cut out at the point of entry of rotational axis 3 into support 2, so that
2~
rotation~l axis 3 can be moved into the directions described. Rotational axis 3 is positionable at any desired point within aperture cone 8, if pins 6 do not strike limiting edge 41 beforehand. Tooth cleaning head 1 shown in Figure 3, as described above, preferably has a symmetrical round shape and the articulation de~rice rests on the axis of symmetry of the cleaning head.
On the underside of support 2, bristles 10 are provided in the form of a bristle crown. Relative to the lengthwise axis of tooth cleaning head 1, bristles 10 run at an angle o~ outward. The bristle crown thus forms a frustroconical jacket. Preferably angle~C is within a range of 25. In forward area 11 of the bristle edge, the bristles travel a short distance parallel to the lengthwise axis of tooth cleaning head 1.
Bristles 10 are cut off here for example, or bent over after heaffng, and directed in the direction shown. It is also possible, however, to leave the pointed edge of the bristles with reference 12, standing ~shown shaded). However the segment which runs in a straight line in the forward area of the bristles has the advantage that the outermost bristles cannot penetrate the gums or the gingival pockets as easily.
Preferably the diameter of the cleaning area 40 at the tips of the bristles is in the vicinity of 15 mm. In other words, the curvature of the circumferential edge of cleaning area 40 lies in the range of curvature of the gingival margin. In addition, the length of bristles 10 and the diameter of support 2 is 10 mm. On the inside, the bristle crown has bristles 10 cut away, producing a cavity 14. Cavity 14 can be used to accommodate toothpaste or one or more knobs of elastic material, which have their tips protruding out of the opening in the -12~
s~avity and can be used to massage the gums. The knobs are preferably made somewhat shorter than the length of bristles 10, so that the knobs (not shown) will contact the gums slightly later than bristles 10 after gentle pressure is applied to the cleaning head.
Instead of bristles 10, cleaning elements in the form of elastic materials can also be used, in which for example the bristle crown consists of a frustroconical section made of rubber. The frustroconical section can have the same details as described above in conjunction with bristles 10 .
When cleaning head 1 with cleaning area 40 is applied to the surface of a tooth, the position of cleaning area 40 automatically adapts to the contour of the surface of the tooth because of the cross ball joint. Due to the continuous polishing motion and the adaptability of the position of cleaning area 40 with respect to the surface contours of the teeth, a considerable cleaning effect is achieved. If tooth cleaning head 1 encounters a gap in the teeth during the polishing movements, the force of the pressure is transmitted in turn via cleaning area 40 to the surface of the tooth causes tooth cleaning head 1 to tilt into the space between the teeth. In other words, the cleaning areas 10 which are located to either side of the joint form lever arms, which exert torques under load, at the distance from the axis of symmetry on which the articulation lies. If the two forces to the right and left of the axis of symmetry are equal, tooth cleaning head 1 will rotate horizontally. On the other hand, if the force is absent on one side, for example if the head is traveling over a space between the teeth, cleaning head 1 will tilt until the bristles strike something once again. Tooth cleaning head -13- ~;~$~
1 can therefore p~netrate the lower-down spaces between the teeth with the forward polishing surface edges during rotary cleaning motions, whereby no area of the too$h surface/ even at the neck of the tooth, is skipped or omitted. The rotational speed of cleaning head 1 is preferably variable and the rotational frequency is in the range from 1 to 20 E~z. It is also advisable to design the rotational direction of cleaning head 1 to be reversible in order to ensure that the cleaning elements wear uniformly or to improve the handling of the toothbrush.
Figure 3 shows support 2 to be covered by an elastic mater~al 9 on the top. Material 9 exhibits elasticity which is sufficiently great that it follows the motions in the rotational axis. Elastic material 9 therefore on the one hand adopts the function of protecting the joint against the penetration of dirt and water. On the other hand, the elastic material exhibits spring characteristics which ensure that tooth cleaning head 1 is pushed back into its basic position when the cleaning elements are rotating freely and are not in contact with the surface of the tooth. In this way, the tooth cleaning head will not make any uncontrolled movements and the user can better estimate the position of cleaning area 40 before reapplying the head to the teeth.
Figure 5 shows a lengthwise section through the forward æhaft 18 of a toothbrush 15. A drive shaft 19, comprising a drive gear 20~ rotates in shaft 18 in a bore. Drive shaft 19 is driven by a motor (not shown) in the handle of toothbrush 15. The lengthwise axis of toothbrush 15 runs along drive shaft 19. In the forward area of the shaft, a chamber 27 is provided in which a shaft 21 is disposed perpendicularly to the 12~
"
lengthwise axis. Shaft 21 is rotatable at the rear end in a bearing 42 and is nondisplacably mounted axially. In Figure 5, shaft 21 corresponds to rotational shaft 3 in Figures 1, 2, and 3. In addition, shaft 21 comprises a gear 23 with a crown gear 22, which is in mesh with drive gear 20. As soon as drive shaft 19 is rotated by the motor (not shown), the power is transmitted to crown gear 22 of gear 23.
seal 24 is provided to prevent dirt or water from penetrating bearing 42 .
A support 2 for bristle tufts 16 is provided on the forward free end of shaft 21, Support 2 has the form of a ring, with bores 17 to receive bristle tufts 16 being positioned diagonally outward at a suitable angle.
The connection between support 2 and shaft 21 is provided by a leaf spring 25 which is shown only in cross section in Figure S, Leaf spring 25 is fastened by mounting points 26 to the forward free end of shaft 21. As shaft 21 rotates, support 2 is rotated together with bristle tufts 16. Instead of bristle tufts 16, rubber knobs or rubber pins like those described above may likewise be used. Similarly, it is also possible to supply water through hollow shaft 21 and it is possible to provide a plurality of supports 2 in the transverse or lengthwise direction of the shaft, whereby addition~l shafts 21 and gears 23 are provided. Supports 2 disposed side by side are spaced sufficiently far from one another that they will not contact one another with their leading bristle tips when tilted out of their basic working posiffons.
Figure 5 shows the basic working position of support 2. If, as described ~bove, a unilateral pressure is exerted on the tips of bristle tufts 16, support 2 will move out of the position shown in Figure 5.
Annular support 2 is cut away in its inside diameter at its upper edge or its free end to the point where sufficient room is provided for pivoting and the inside of support 2 does not touch shaft 21. On the other hand, however, it is also possible to dimension the free space between support 2 and shaft 21 in such fashion that shaft 21 serves as a stop and limit to the tilting motion.
Figures 6~, 6B, and 6C show various embodiments of leaf spring 25 in top view. Leaf springs 25 comprise external and radially e~ctending retaining ribs 29, which are fastened to the underside of annular support 2 shown in Figure 5. ~eaf springs 25 have recesses 28 to allow bristle tufts 16 to pass through. The central section 30 of each leaf springs 25 is attached to a fastening point 26 at the free end of shaft 21 and central sections 30 are connected with the outer retaining ribs 29 by spring segments 31. Leaf springs 25 shown in Figure 6 are completely flat and are given the shapes shown for example by etching or stamping. Retaining ribs 299 spring segments 31, and central segments 30 therefore lie in a single plane so that central segments 30 can be moved into another plane relative to retaining ribs 29, so that spring elements 31 have the shapes shown in Figure 6. The excess length, in other words spring elements 31 are longer than the shortest distance between a retaining lib 29 and a central section 30, makes it possible to tilt retaining ribs 29 upward or downward relative to the plane of central sections 30. Since retaining ribs 29 merge with spring elements 31 independèntly of one another it is possible to tilt one part of the spFing elements u pward and the other half downward in the -16~ ~ Z ~
plane of the drawing. Preferably, two retaining ribs 29 are always opposite one another so tha~ a line of symmetry is formed around which support 2 is tiltably mounted. Figure 6A shows spring elements in the form of a compressed ring. In addition, Figure 6B also shows spring segments 31 in the form of loops and Figure 6C shows them in the shape of ribs arranged in the form of a vortex.
Figure 7 shows another embodiment o a tooth cleaning head 1.
Support 2, which holds bristle tufts 16, is connected by struts 33 with an inner plate 32. Struts 33 extend radially from plate 32 to the inner edge of support 2. Preferably once again an even number of struts 33 is provided, so that two struts, located opposite one another can form a rotational axis about which the cleaning head can tilt. Struts 33 are curved into an S shape according to the direction of the cross section shown in Figure 7 and extend with excess length into the interior of support 2. The S shape is produced by the transition from plate 32, at which struts 33 has a first curved segment, to the second curved segment, which is formed on the upper edge of support 2. The S
shape or conically inwardly directed path of struts 33 causes plate 32 to sink into the interior of cavity 43 in support 2. The excess length of struts 33 and their path makes support 2 pivotable or tiltable about rotational shaft 3 within a specific angle range from its basic working position. Struts 33 in this regard simultaneously operate as spring elements, if they are injection-molded for example together with supports 2 out of a single piece of plastic. Accordingly, struts 33, ater tilting of support 2, attempt to resume their shape once again as deined by the manufacturing process. The spring characteristics of -17- 12~
struts 33 can be varied by the size and width of 810ts 35 between stru$s 33 as well as by the thickness of struts 33.
It is likewise possible to provide breakaway points 36 on struts 33 so that if one of supports 2 should break off inner plate 32 no sharp edges will be directed toward the gum. In other words the breakaway points preferably lie inside chamber 27 (see Figure 5) preventing any contact between broken off strut ends and the gum. Plate 32 also offers the advantage that the round leading edges prevent any damage to the gum. In the middle of plate 32, a depression is provided for example for a rubber knob. In addition it is also possible, as in the cases described above, to fill interior space 43 completely with a rubber elastic material so that no toothpaste can enter chamber 27 through slot 35 (see Figure 5). The embodiment of the tooth cleaning head 1 in Figure 7 also offers the advantage that the articulation device composed of struts 33 is as close as possible to the cleaning areas. This improves the positionability of the cleaning head, which is striven for in the same way as in the embodiments described hereinabove.
In order to fasten tooth cleaning head 1 of Figure 7 to shaft 21, rotational shaft 3 can be designed for example to have a square cross section for nonrotational mounting, and can be inserted into a corresponding bore in the chamber in shaft 21. A projection 38 is provided for locking, whereby projection 38 is flexibly mounted through a cut 37 in rotary shaft 3. Cleaning head 1 can thus be mounted on shaft 3 and replaced if necessary. In contrast to all of the articulation devices described hereinabove, provided between rotary shaft 3 and t -1- ~2~
8uppor1 ~, lt ~s liket~ise possible to mount 6upport 2 ~lgid}y OSl ~haft 21 Qnd to provicle the a~iculstion device instead of be~ing ~2~ It i~ elso pos8ible to provide the nrticul~tion de~rlse in til~ middle of ~haf~ 21.
I
In Figure 7, etruts 33 which are disposed radi~ on inneI~ plate 32 are curved ~long the sxis of symmetry or rotational ~ds 3. As ~ result, inner plate 32 is mounted offset ~n ~he len~thwise direction downward in inner cham~er 43 of support 2, while in other embodiment8 plate 32 can al~o be disposed upward outside 6upport 2, In other words ~ the fastenins~ point of strut 33 or rotational a~s 3 is closer to cie~ning elements lO than the fastening point of the other end of ~t~ut8 33 to support 21~ In a modification of this embodiment, it ~s po6s~ble ~or example to connect plate 32 ~rith the inner ed~e of support 2 in 6uch fashion that the curvatures of the radi~ ~truts 33, li~e the spring elemen~s 31 (see ~igure 6) can only he seen in a top v~ew of cle8ning head 1, whereby ~ll Btl`UtS 33 lie ln the ~ame plane, the orle to which rotation~l ax~ 3 is perpendicu~ar. In Figure 7, the cur~ture of ~tru~s 33 can only be seen in the section shown. ~t is also po~s~ble to pro~,ride ætruts 33 whose curvatures are combinations of the possi~ es shown in Figures 6 and 7. In this connectlon, for example the str-lts 33 ~hown in Figure 7 are also curved laterally.
By di~posing the rota~on or tilting point of bristle he~d 1 ~long the direction of rotational axis 3, it is possible to ~ary the tilting or piYoting circle of bri~tle head l, Here, the radius of the tilting or pi~rotinf~; circle corresponds to struts 33~ The distance between rotational axis 3 ~nd clea3ling surface 4~, which corresponds to the 2~
lever arm, is not equal here to the radius through which bristle head 1 is pivoted.
In addition, the location of the rotation or tilting point between support 2 and cleaning area 40 offers the advantage that the weights of support 2 and bristles 16 can be balanced. The rotation or tilting point therefore preferably lies at the center of gravity of bristle head 1 in order to avoid imbalances during rotation. Freely rotaffng bristle head 1 retains its basic working position even when rotational axis 3 is horizontal and especially at high rpm.
Instead of the struts 33 shown in Figure 7 it is also possible to provide an elastic material which connects support 2 with rotational axis 3. The elastic material then takes over the articulation and spring element function. For example, such a bristle head 1 is manufactured by a two-component injection molding process whereby in the first work step, for example an annular support 2 and rotational axis 3 are formed and in a second work step the elastic material is injected. In order the improved the adhesion of the elastic material to support 2, suitable undercuts, edges, or surface-increasing parts are provided.
The invention is not limited to the embodiments described above but also allows additional embodiments within the scope. In particular it has been found advantageous for various applications to allow the pivoting end or tilting motion of brush head 1 by means OI a bendable or flexible rotational axis 3. This measure permits eliminating the articulation designs of the other embodiments and allows advantages in -20~
terms of manufacturing cost. In these embodiments, a one-piece design of rotational axis 3 and support 2 by the injection molding process or the like suggests itself. All of the embodiments of the toothbrush according to the invention which do not relate to the design of articulation devices 4, 25, and 33 as disclosed in this document likewise serve for the advantageous improvement to a toothbrush with a flexible and/or bendable rotational axis 3.
rotation~l axis 3 can be moved into the directions described. Rotational axis 3 is positionable at any desired point within aperture cone 8, if pins 6 do not strike limiting edge 41 beforehand. Tooth cleaning head 1 shown in Figure 3, as described above, preferably has a symmetrical round shape and the articulation de~rice rests on the axis of symmetry of the cleaning head.
On the underside of support 2, bristles 10 are provided in the form of a bristle crown. Relative to the lengthwise axis of tooth cleaning head 1, bristles 10 run at an angle o~ outward. The bristle crown thus forms a frustroconical jacket. Preferably angle~C is within a range of 25. In forward area 11 of the bristle edge, the bristles travel a short distance parallel to the lengthwise axis of tooth cleaning head 1.
Bristles 10 are cut off here for example, or bent over after heaffng, and directed in the direction shown. It is also possible, however, to leave the pointed edge of the bristles with reference 12, standing ~shown shaded). However the segment which runs in a straight line in the forward area of the bristles has the advantage that the outermost bristles cannot penetrate the gums or the gingival pockets as easily.
Preferably the diameter of the cleaning area 40 at the tips of the bristles is in the vicinity of 15 mm. In other words, the curvature of the circumferential edge of cleaning area 40 lies in the range of curvature of the gingival margin. In addition, the length of bristles 10 and the diameter of support 2 is 10 mm. On the inside, the bristle crown has bristles 10 cut away, producing a cavity 14. Cavity 14 can be used to accommodate toothpaste or one or more knobs of elastic material, which have their tips protruding out of the opening in the -12~
s~avity and can be used to massage the gums. The knobs are preferably made somewhat shorter than the length of bristles 10, so that the knobs (not shown) will contact the gums slightly later than bristles 10 after gentle pressure is applied to the cleaning head.
Instead of bristles 10, cleaning elements in the form of elastic materials can also be used, in which for example the bristle crown consists of a frustroconical section made of rubber. The frustroconical section can have the same details as described above in conjunction with bristles 10 .
When cleaning head 1 with cleaning area 40 is applied to the surface of a tooth, the position of cleaning area 40 automatically adapts to the contour of the surface of the tooth because of the cross ball joint. Due to the continuous polishing motion and the adaptability of the position of cleaning area 40 with respect to the surface contours of the teeth, a considerable cleaning effect is achieved. If tooth cleaning head 1 encounters a gap in the teeth during the polishing movements, the force of the pressure is transmitted in turn via cleaning area 40 to the surface of the tooth causes tooth cleaning head 1 to tilt into the space between the teeth. In other words, the cleaning areas 10 which are located to either side of the joint form lever arms, which exert torques under load, at the distance from the axis of symmetry on which the articulation lies. If the two forces to the right and left of the axis of symmetry are equal, tooth cleaning head 1 will rotate horizontally. On the other hand, if the force is absent on one side, for example if the head is traveling over a space between the teeth, cleaning head 1 will tilt until the bristles strike something once again. Tooth cleaning head -13- ~;~$~
1 can therefore p~netrate the lower-down spaces between the teeth with the forward polishing surface edges during rotary cleaning motions, whereby no area of the too$h surface/ even at the neck of the tooth, is skipped or omitted. The rotational speed of cleaning head 1 is preferably variable and the rotational frequency is in the range from 1 to 20 E~z. It is also advisable to design the rotational direction of cleaning head 1 to be reversible in order to ensure that the cleaning elements wear uniformly or to improve the handling of the toothbrush.
Figure 3 shows support 2 to be covered by an elastic mater~al 9 on the top. Material 9 exhibits elasticity which is sufficiently great that it follows the motions in the rotational axis. Elastic material 9 therefore on the one hand adopts the function of protecting the joint against the penetration of dirt and water. On the other hand, the elastic material exhibits spring characteristics which ensure that tooth cleaning head 1 is pushed back into its basic position when the cleaning elements are rotating freely and are not in contact with the surface of the tooth. In this way, the tooth cleaning head will not make any uncontrolled movements and the user can better estimate the position of cleaning area 40 before reapplying the head to the teeth.
Figure 5 shows a lengthwise section through the forward æhaft 18 of a toothbrush 15. A drive shaft 19, comprising a drive gear 20~ rotates in shaft 18 in a bore. Drive shaft 19 is driven by a motor (not shown) in the handle of toothbrush 15. The lengthwise axis of toothbrush 15 runs along drive shaft 19. In the forward area of the shaft, a chamber 27 is provided in which a shaft 21 is disposed perpendicularly to the 12~
"
lengthwise axis. Shaft 21 is rotatable at the rear end in a bearing 42 and is nondisplacably mounted axially. In Figure 5, shaft 21 corresponds to rotational shaft 3 in Figures 1, 2, and 3. In addition, shaft 21 comprises a gear 23 with a crown gear 22, which is in mesh with drive gear 20. As soon as drive shaft 19 is rotated by the motor (not shown), the power is transmitted to crown gear 22 of gear 23.
seal 24 is provided to prevent dirt or water from penetrating bearing 42 .
A support 2 for bristle tufts 16 is provided on the forward free end of shaft 21, Support 2 has the form of a ring, with bores 17 to receive bristle tufts 16 being positioned diagonally outward at a suitable angle.
The connection between support 2 and shaft 21 is provided by a leaf spring 25 which is shown only in cross section in Figure S, Leaf spring 25 is fastened by mounting points 26 to the forward free end of shaft 21. As shaft 21 rotates, support 2 is rotated together with bristle tufts 16. Instead of bristle tufts 16, rubber knobs or rubber pins like those described above may likewise be used. Similarly, it is also possible to supply water through hollow shaft 21 and it is possible to provide a plurality of supports 2 in the transverse or lengthwise direction of the shaft, whereby addition~l shafts 21 and gears 23 are provided. Supports 2 disposed side by side are spaced sufficiently far from one another that they will not contact one another with their leading bristle tips when tilted out of their basic working posiffons.
Figure 5 shows the basic working position of support 2. If, as described ~bove, a unilateral pressure is exerted on the tips of bristle tufts 16, support 2 will move out of the position shown in Figure 5.
Annular support 2 is cut away in its inside diameter at its upper edge or its free end to the point where sufficient room is provided for pivoting and the inside of support 2 does not touch shaft 21. On the other hand, however, it is also possible to dimension the free space between support 2 and shaft 21 in such fashion that shaft 21 serves as a stop and limit to the tilting motion.
Figures 6~, 6B, and 6C show various embodiments of leaf spring 25 in top view. Leaf springs 25 comprise external and radially e~ctending retaining ribs 29, which are fastened to the underside of annular support 2 shown in Figure 5. ~eaf springs 25 have recesses 28 to allow bristle tufts 16 to pass through. The central section 30 of each leaf springs 25 is attached to a fastening point 26 at the free end of shaft 21 and central sections 30 are connected with the outer retaining ribs 29 by spring segments 31. Leaf springs 25 shown in Figure 6 are completely flat and are given the shapes shown for example by etching or stamping. Retaining ribs 299 spring segments 31, and central segments 30 therefore lie in a single plane so that central segments 30 can be moved into another plane relative to retaining ribs 29, so that spring elements 31 have the shapes shown in Figure 6. The excess length, in other words spring elements 31 are longer than the shortest distance between a retaining lib 29 and a central section 30, makes it possible to tilt retaining ribs 29 upward or downward relative to the plane of central sections 30. Since retaining ribs 29 merge with spring elements 31 independèntly of one another it is possible to tilt one part of the spFing elements u pward and the other half downward in the -16~ ~ Z ~
plane of the drawing. Preferably, two retaining ribs 29 are always opposite one another so tha~ a line of symmetry is formed around which support 2 is tiltably mounted. Figure 6A shows spring elements in the form of a compressed ring. In addition, Figure 6B also shows spring segments 31 in the form of loops and Figure 6C shows them in the shape of ribs arranged in the form of a vortex.
Figure 7 shows another embodiment o a tooth cleaning head 1.
Support 2, which holds bristle tufts 16, is connected by struts 33 with an inner plate 32. Struts 33 extend radially from plate 32 to the inner edge of support 2. Preferably once again an even number of struts 33 is provided, so that two struts, located opposite one another can form a rotational axis about which the cleaning head can tilt. Struts 33 are curved into an S shape according to the direction of the cross section shown in Figure 7 and extend with excess length into the interior of support 2. The S shape is produced by the transition from plate 32, at which struts 33 has a first curved segment, to the second curved segment, which is formed on the upper edge of support 2. The S
shape or conically inwardly directed path of struts 33 causes plate 32 to sink into the interior of cavity 43 in support 2. The excess length of struts 33 and their path makes support 2 pivotable or tiltable about rotational shaft 3 within a specific angle range from its basic working position. Struts 33 in this regard simultaneously operate as spring elements, if they are injection-molded for example together with supports 2 out of a single piece of plastic. Accordingly, struts 33, ater tilting of support 2, attempt to resume their shape once again as deined by the manufacturing process. The spring characteristics of -17- 12~
struts 33 can be varied by the size and width of 810ts 35 between stru$s 33 as well as by the thickness of struts 33.
It is likewise possible to provide breakaway points 36 on struts 33 so that if one of supports 2 should break off inner plate 32 no sharp edges will be directed toward the gum. In other words the breakaway points preferably lie inside chamber 27 (see Figure 5) preventing any contact between broken off strut ends and the gum. Plate 32 also offers the advantage that the round leading edges prevent any damage to the gum. In the middle of plate 32, a depression is provided for example for a rubber knob. In addition it is also possible, as in the cases described above, to fill interior space 43 completely with a rubber elastic material so that no toothpaste can enter chamber 27 through slot 35 (see Figure 5). The embodiment of the tooth cleaning head 1 in Figure 7 also offers the advantage that the articulation device composed of struts 33 is as close as possible to the cleaning areas. This improves the positionability of the cleaning head, which is striven for in the same way as in the embodiments described hereinabove.
In order to fasten tooth cleaning head 1 of Figure 7 to shaft 21, rotational shaft 3 can be designed for example to have a square cross section for nonrotational mounting, and can be inserted into a corresponding bore in the chamber in shaft 21. A projection 38 is provided for locking, whereby projection 38 is flexibly mounted through a cut 37 in rotary shaft 3. Cleaning head 1 can thus be mounted on shaft 3 and replaced if necessary. In contrast to all of the articulation devices described hereinabove, provided between rotary shaft 3 and t -1- ~2~
8uppor1 ~, lt ~s liket~ise possible to mount 6upport 2 ~lgid}y OSl ~haft 21 Qnd to provicle the a~iculstion device instead of be~ing ~2~ It i~ elso pos8ible to provide the nrticul~tion de~rlse in til~ middle of ~haf~ 21.
I
In Figure 7, etruts 33 which are disposed radi~ on inneI~ plate 32 are curved ~long the sxis of symmetry or rotational ~ds 3. As ~ result, inner plate 32 is mounted offset ~n ~he len~thwise direction downward in inner cham~er 43 of support 2, while in other embodiment8 plate 32 can al~o be disposed upward outside 6upport 2, In other words ~ the fastenins~ point of strut 33 or rotational a~s 3 is closer to cie~ning elements lO than the fastening point of the other end of ~t~ut8 33 to support 21~ In a modification of this embodiment, it ~s po6s~ble ~or example to connect plate 32 ~rith the inner ed~e of support 2 in 6uch fashion that the curvatures of the radi~ ~truts 33, li~e the spring elemen~s 31 (see ~igure 6) can only he seen in a top v~ew of cle8ning head 1, whereby ~ll Btl`UtS 33 lie ln the ~ame plane, the orle to which rotation~l ax~ 3 is perpendicu~ar. In Figure 7, the cur~ture of ~tru~s 33 can only be seen in the section shown. ~t is also po~s~ble to pro~,ride ætruts 33 whose curvatures are combinations of the possi~ es shown in Figures 6 and 7. In this connectlon, for example the str-lts 33 ~hown in Figure 7 are also curved laterally.
By di~posing the rota~on or tilting point of bristle he~d 1 ~long the direction of rotational axis 3, it is possible to ~ary the tilting or piYoting circle of bri~tle head l, Here, the radius of the tilting or pi~rotinf~; circle corresponds to struts 33~ The distance between rotational axis 3 ~nd clea3ling surface 4~, which corresponds to the 2~
lever arm, is not equal here to the radius through which bristle head 1 is pivoted.
In addition, the location of the rotation or tilting point between support 2 and cleaning area 40 offers the advantage that the weights of support 2 and bristles 16 can be balanced. The rotation or tilting point therefore preferably lies at the center of gravity of bristle head 1 in order to avoid imbalances during rotation. Freely rotaffng bristle head 1 retains its basic working position even when rotational axis 3 is horizontal and especially at high rpm.
Instead of the struts 33 shown in Figure 7 it is also possible to provide an elastic material which connects support 2 with rotational axis 3. The elastic material then takes over the articulation and spring element function. For example, such a bristle head 1 is manufactured by a two-component injection molding process whereby in the first work step, for example an annular support 2 and rotational axis 3 are formed and in a second work step the elastic material is injected. In order the improved the adhesion of the elastic material to support 2, suitable undercuts, edges, or surface-increasing parts are provided.
The invention is not limited to the embodiments described above but also allows additional embodiments within the scope. In particular it has been found advantageous for various applications to allow the pivoting end or tilting motion of brush head 1 by means OI a bendable or flexible rotational axis 3. This measure permits eliminating the articulation designs of the other embodiments and allows advantages in -20~
terms of manufacturing cost. In these embodiments, a one-piece design of rotational axis 3 and support 2 by the injection molding process or the like suggests itself. All of the embodiments of the toothbrush according to the invention which do not relate to the design of articulation devices 4, 25, and 33 as disclosed in this document likewise serve for the advantageous improvement to a toothbrush with a flexible and/or bendable rotational axis 3.
Claims (31)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Electric toothbrush comprising a handle, a tooth cleaning head, said tooth cleaning head having a body and cleaning element structure mounted in annular array on said body, a drive in said handle for driving said tooth cleaning head in rotation about a rotational axis generally coaxial with said cleaning element structure, and articulation structure coupled between said drive and said cleaning element structure, said articulation structure being disposed adjacent the center of gravity of said tooth cleaning head and permitting tilting movement of said cleaning element structure relative to said body as said tooth cleaning head is driven in rotation about its rotational axis by said drive.
2. Toothbrush according to Claim 1 wherein said articulation structure includes restoring means tending to return said cleaning element structure to a neutral position.
3. Toothbrush according to Claim 1 wherein said articulation structure is located between said body and said cleaning element structure.
4. Toothbrush according to any one of Claims 1 to 3 wherein said articulation structure includes a joint ball, a ball shell, a drive pin in one of said ball and ball shell and an annular groove in the other of said ball and ball shell in which said drive pin is received.
5. Toothbrush according to Claim 1 wherein said articulation structure is located between said body and the free end of said cleaning element structure.
6. Toothbrush according to Claim 1 wherein said articulation structure comprises a spring element that tends to return said tooth cleaning head to a basic position.
7. Toothbrush according to Claim 6 wherein said articulation structure is of leaf spring form.
8. Toothbrush according to Claim 7 wherein said cleaning element structure includes a plurality of cleaning elements, said leaf spring form comprises a plurality of radial retaining ribs, said ribs being spaced to allow cleaning elements to pass through, and said body is connected by spring segments to said retaining ribs.
9. Toothbrush according to Claim 2 wherein said restoring means comprises a plurality of struts which exhibit spring-elastic properties and extend radially from the rotational axis of said tooth cleaning head.
10. Toothbrush according to Claim 9 wherein said tooth cleaning head defines a chamber, and each said strut has breakaway structure located within said chamber.
11. Toothbrush according to Claim 9 wherein said axis body, said struts, and a support for said cleaning element structure are a one piece molded plastic member.
12. Toothbrush according to Claim 2, wherein said restoring means comprises elastic material.
13. Toothbrush according to Claim 1 wherein said cleaning element structure array has a diameter in the vicinity of fifteen millimeters at its leading edge.
14. Toothbrush according to Claim 1 wherein said cleaning element structure array extends outward at an angle of about 25°.
15. Toothbrush according to Claim 1 wherein said cleaning element structure has a length in the vicinity of ten millimeters.
16. Toothbrush according to Claim 1 wherein said cleaning element structure has a portion parallel to the lengthwise axis of said tooth cleaning head at its leading edge.
17. Toothbrush according to Claim 13 wherein said cleaning element structure is an elastic frustoconical body.
18. Toothbrush according to Claim 17 wherein said frustoconical body has a cavity at the center to receive toothpaste.
19. Toothbrush according to any one of Claims 1 to 3 wherein the tilting movement allowed by said articulation structure is in the range of 30°.
20. Toothbrush according to any one of Claims 1 to 3 wherein the rotational frequency of said tooth cleaning head as driven by said drive is in the vicinity of 1 to 20 Hz.
21. Toothbrush according to claim 1, claim 2 or claim 5 wherein said articulation structure is located along said rotational axis of said tooth cleaning head.
22. Toothbrush according to any one of Claims 1 to 3 wherein said articulation structure includes elastic material between said body and said drive to return said cleaning element structure towards a neutral position.
23. Toothbrush according to Claim 1 wherein said articulation structure includes flexible rotational axis structure.
24. Toothbrush according to Claim 23 wherein said tooth cleaning head comprises a one-piece member that includes said body and said articulation structure.
25. Electric toothbrush comprising a housing, a drive motor in said housing, a tooth cleaning head at one end of said housing, said tooth cleaning head having a body and cleaning element structure mounted in annular array on said body, drive means coupled between said tooth cleaning head and said drive motor for rotating said tooth cleaning head at a rotational frequency in the vicinity of one to twenty hertz, and articulation structure coupled between said drive means and said cleaning element structure, said articulation structure permitting tilting movement of said cleaning element structure as a unit under the influence of external force on said cleaning element structure relative to said drive means about a point near the center of gravity of said tooth cleaning head to permit tilting movement of said cleaning element structure to conform with contours of the teeth being cleaned, said articulation structure including restoring means tending to return said cleaning element structure towards a neutral position.
26. The toothbrush of claim 25 wherein said articulation structure includes ball and socket joint structure in said body and said restoring means includes elastic material that tends to return said cleaning element structure towards said neutral position.
27. The toothbrush of claim 25 wherein said articulation structure includes resilient leaf spring structure that tends to return said cleaning element structure towards said neutral position.
28. The toothbrush of claim 27 wherein said cleaning element structure is connected to said body by said resilient leaf spring structure.
29. The toothbrush of claim 25 wherein said articulation structure includes plural resilient strut structure that tends to return said cleaning element structure towards said neutral position.
30. The toothbrush of claim 29 wherein said cleaning element structure is connected to said body by said plural resilient strut structure.
31. The toothbrush of claim 30 wherein said cleaning element structure includes a plurality of tooth cleaning elements disposed in circular array, said tooth cleaning elements having a length in the vicinity of one centimeter and extending outwardly at an angle in the vicinity of 25°, and said array having a diameter in the vicinity of fifteen millimeters at the leading edges of said tooth cleaning elements.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3431225.0 | 1984-08-24 | ||
| DE3431225 | 1984-08-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1268011A true CA1268011A (en) | 1990-04-24 |
Family
ID=6243835
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000489165A Expired - Fee Related CA1268011A (en) | 1984-08-24 | 1985-08-21 | Electrical toothbrush |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0173150A3 (en) |
| CA (1) | CA1268011A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7941886B2 (en) | 2003-09-19 | 2011-05-17 | Braun Gmbh | Toothbrushes |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3911303C1 (en) * | 1989-04-07 | 1990-08-23 | Braun Ag, 6000 Frankfurt, De | |
| DE4308444A1 (en) * | 1993-03-17 | 1994-09-22 | Braun Ag | Brush part for an electric toothbrush |
| GB2299264B (en) * | 1995-03-27 | 1999-10-20 | Naresh Gathani | A toothbrush to reduce tooth abrasion and improve efficiency |
| DE19608226A1 (en) * | 1996-03-04 | 1997-09-11 | Kurt Dipl Ing Kessler | Toothbrush with elastically articulated interchangeable brush head |
| US6799346B2 (en) | 2002-01-04 | 2004-10-05 | Atico International Usa, Inc. | Toothbrush with oppositely reciprocating brush heads |
| KR101026009B1 (en) | 2009-06-03 | 2011-03-30 | 우정완 | Rotary toothbrush |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2888697A (en) * | 1955-08-29 | 1959-06-02 | Coggeshall Edward Owen | Rotary dental brush |
| AT353949B (en) * | 1975-09-30 | 1979-12-10 | Bioengineering Research | TOOTHBRUSH |
| DE2654853A1 (en) * | 1976-12-03 | 1978-06-08 | Wiethoelter Horst | Tooth brush with round bristle groups - has pivot mounted sets of bristles mounted on spherical heads at oblique angles |
| CA1120665A (en) * | 1979-02-21 | 1982-03-30 | Manuel Del Rosario | Toothbrush |
-
1985
- 1985-08-09 EP EP85110051A patent/EP0173150A3/en not_active Withdrawn
- 1985-08-21 CA CA000489165A patent/CA1268011A/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7941886B2 (en) | 2003-09-19 | 2011-05-17 | Braun Gmbh | Toothbrushes |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0173150A2 (en) | 1986-03-05 |
| EP0173150A3 (en) | 1987-08-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |