EP0016564A1

EP0016564A1 - Disposable head toothbrush

Info

Publication number: EP0016564A1
Application number: EP80300613A
Authority: EP
Inventors: Alan Hugo Lambert Cosby
Original assignee: Gb Kent And Sons Ltd
Current assignee: Gb Kent And Sons Ltd
Priority date: 1979-03-02
Filing date: 1980-02-29
Publication date: 1980-10-01

Abstract

A toothbrush (10) comprising a head portion (12) having a plurality of tufts extending therefrom, a handle portion (11), the portions (11 and 12) having interengagable formations (15,44; 19,38; 20,40) whereby the head portion (12) is adapted to be removably carried by the handle portion (11), and snap engagement means (21,41) sothatwhen the head portion (12) is located on the handle portion (11) and moved rearwardly thereof, the snap engagement means (21,41) operates with a 'clicking' sound.

Description

This invention relates to brushes and particularly to toothbrushes.
In the interest of oral hygiene, dentists have recommended that toothbrushes be replaced as frequently as possible since, after a relatively short period of use, tufts of the brushes become flattened and no longer effectively clean teeth. However, with the increasing cost of plastics materials, toothbrushes are becoming more expensive and the cost does not encourage regular replacement. As a result, the general standard of oral hygiene is lower' than would be the case if toothbrushes were less expensive to replace.
According to the present invention there is provided a brush comprising a head portion having a plurality of tufts extending therefrom, a handle portion, the portions having interengagable formations whereby the head portion is adapted to be removably carried by the handle portion and when so carried to be movable relative to the handle portion in a predetermined direction and snap engagement means for resisting a force applied in the said direction to separate the portions one from the other, the arrangement being such that the snap engagement means resists said force until a component of the force exceeds a predetermined magnitude causing release of the snap engagement means to permit separation of the said portions.
The interengable formations may comprise a plug and a socket.
The plug and socket may be of complementary configurations.
The snap engagement means may comprise complementary abutment surfaces carried by the plug and socket respectively.
One of said abutment surfaces may be located in the socket.
The socket may be provided with a cavity which tapers in a longitudinal direction of the recess.
The plug may comprise a pair of transversely spaced elongate members adapted to engage therebetween said abutment surface in the socket.
A wall of the socket may be inclined inwardly towards a longitudinal axis of the socket.
The socket may be open in a direction transverse to the said longitudinal axis and in a direction parallel to said longitudinal axis.
The socket may be in the heed portion.
The head portion may comprise a surface having the tufts extending therefrom, the surface being inclined from a leading edge thereof to a trailing edge thereof.
The head portion may comprise an additional surface having tufts extending therefrom, the additional ' surface extending at an angle to the said surface.
Following is a description, by way of example only and with reference to the accompanying drawings, of one method of carrying the invention into effect.
In the drawings:-

FIGURE 1 is a plan view of one embodiment of a toothbrush in accordance with the present invention,
FIGURE 2 is an elevation of the toothbrush shown in FIGURE 1,
FIGURE 3 is a diagrammatic representation showing the manner in which a head and a handle of the toothbrush shown in FIGURES 1 and 2 are interconnected,
FIGURE 4 is a longitudinal cross section of the head and handle of the toothbrush shown in FIGURES 1 to 4 , the head and handle being separate one from the other,
FIGURE 5 is a cross section on the line - I of FIGURE 1,
FIGURE 6 is an enlarged cross section on the line II- II of FIGURE 5,
FIGURE 7 is an enlarged cross section on the line III - III of FIGURE 5,
FIGURE 8 is an enlarged cross section on the line IV - IV of FIGURE 5,
FIGURES 9 to 12 are diagrammatic representations, shown partly in cross section, of another example of a toothbrush in accordance with the present invention,
FIGURES 13 to 16 are diagrammatic representations, shown partly in cross section, of another embodiment of a toothbrush in accordance with the present invention,
FIGURES 17 to 20 are diagrammatic representations, shown partly in cross section, of another embodiment of a toothbrush in accordance with the present invention, and
FIGURES 21 to 24 are diagrammatic representations, shown partly in cross section, of another example of a toothbrush in accordance with the present invention.

Referring now to FIGURES 1 to 8 of the drawings, there is shown a toothbrush 10 comprising a handle portion 11 and a head portion 12 each being of synthetic plastics material.
The handle portion 11 is elongate and comprises a flat upper surface 13, a flat lower surface 14, a front wall 15, a rear wall 16 and side walls 17 and 18. The front wall 15 is inclined rearwardly towards the upper surface 13, the rear wall 16 is inclined forwardly towards the upper surface 13 and the side walls 17, 18 converge towards the upper surface 13. The lower wall 14 is provided with a flat relieved portion 19 extending rearwardly from the front wall 15 and a rearwardly, downwardly inclined abutment surface 20 contiguous with a rear edge of the relieved portion 19. The lower surface 14 also is provided ion 19. The lower surface 14 also is provided with a centrally located recess 21 located on a central longitudinal axis of the lower surface 14 and spaced longitudinally rearwardly from the abutment surface 20. The handle portion 11 in longitudinal cross section tapers in a forward direction thereof towards the front wall 15, as shown in FIGURES 2, 4 and 5. The handle portion 11 is provided with an aperture 22 extending from the upper surface 13 to the lower surface 14 thereof, the aperture 22 being located adjacent the rear wall 16.
The head portion 12 is of substantially elongate rectangular configuration in plan and comprises an upper surface 23, a lower surface 24, a front wall 25, a rear wall 26 and side walls 27, 28. The upper surface 23 is substantially flat and is inclined rearwardly from the front wall 25. The lower surface 24 is substantially flat and has a forward portion 29 which is downwardly rearwardly inclined from the front wall 25. The front wall 25 is downwardly rearwardly inclined towards the forward portion 29 of the lower surface 24. The front wall 25 has an upper surface 30 inclined rearwardly towards the upper surface 23 of the head portion 12.
The rear wall 26 has an upper surface 31 inclined forwardly towards the upper surface 23 of the head portion 12 and a lower surface 32 inclined forwardly and downwardly towards the lower surface 24 of the head portion 12. The side walls 27 and 28 have upper surfaces 33 and 34 respectively which are inclined upwardly and inwardly towards the upper surface 23 of the head portion 12.
The lower surface 24 and the forward portion 29 thereof are provided with a plurality of recesses 35, the recesses being arranged in columns and rows when the head portion 12 is viewed in underneath plan. Each of the recesses 35 has located therein a tuft 36, the lengths of the tufts extending from the forward portion 29 being longer Than the tufrs extending from the remaining portion of the lower surface 24 so that the tips of the tufts all lie in a common plane.
The head portion 12 is provided with a groove 37 in the upper surface 23, the groove 37 extending longitudinally forwardly through the rear wall 26. The groove 37 is provided with a substantially flat lower surface 38 having a stepped lower portion 39 adjacent the rear wall 26 and a rearwardly downwardly inclined abutment surface 40 located between and contiguous with the lower surface 38 and the lower stepped portion 39 thereof. The lower stepped portion 39 is provided with an upstanding, centrally located projection 41. The groove 37 is provided with side walls 42, 43 which converge towards the upper surface 23 of the head portion 12. The groove 37 also is provided with a front wall 44 inclined rearwardly and upwardly towards the upper surface 23 of the head portion 12.
The dimensions of the groove 37 are such that a tip of the handle portion 11 from the front wall 15 thereof to a location rearwardly of the recess 21 is adapted to be received longitudinally in the groove 37 with an interference fit. In this manner, when the tip of the handle portion 11 is inserted in the groove 37, the surface of the relieved portion 19 slides longitudinally forwardly of the groove 37 in contact with the lower surface 38 thereof and the upwardly converging side walls 17, 18 of the tip slide in contact with the side walls 42 and 43 of the groove 37. Since the handle portion 11 in longitudinal cross section tapers in a forward direction thereof towards the front wall 15, the reaction of the upwardly converging side walls 42, 43 of the groove 37 and the side walls 17, 18 of the handle portion 11 during the forward movement of the tip of the handle portion 11 in the groove 37 causes the portion of the lower surface 14 of the handle portion adjacent the abutment surface 20 to be urged with progressively increasing force towards the lower stepped portion 39 of the groove 37, when in contact with the portion 39, so that the projection 41 upon roving in contact with the side portion of the lower surface 14 snaps into engagement with the recess 21 as the abutment surface 19 engages the abutment surface 40.
Relative movement of the handle portion 11 and the head portion 12 in a longitudinal direction of the handle portion 11 to separate the handle portion 11 and the head portion 12 from one another is resisted due to reaction of the projection 41 and the surface of the recess 21. However, when the force tending to separate the head portion 12 from the handle portion 11 exceeds a predetermined magnitude, the reaction is overcome resulting in separation of the projection 41 and the recess 21 and separation of the handle portion and the head portion from one another.
The dimensions of the groove 37 are also such that the front wall 15 of the handle portion 11 when received fully in the groove 37 abuts the front wall 15 of the handle portion 11. Since the front wall 44 of the groove 37 is inclined rearwardly and upwardly towards the upper surface 23 of the head portion 12 and the front wall 15 of the handle portion 11 is inclined rearwardly towards the upper surface 13 thereof, and since the side walls 42, 43 converge and abut the side walls 17, 18 of the handle portion 11 at the tip thereof, the head portion 12 is positively retained on the handle portion 11 during manipulation of the toothbrush 10 in use.
Furthermore, the tufts 36 extending from the forward portion 29 of the lower surface 24 of the head portion 12 are of greater length than the remaining tufts and thereby provide greater flexibility than the remaining tufts. In this manner, the tufts ₃6 are specifically adapted to carry out the functions of cleaning teeth in that the longer flexible tufts are specifically suited for sweeping rear teeth while the shorter less flexible tufts are suited for sweeping front teeth and gums.
Referring now to FIGURES 9 to 12 of the drawings, there is shown another embodiment of a toothbrush 50 comprising an elongate handle portion 51 and an elongate head portion 52 each of synthetic plastics material. The handle portion 51 comprises an elongate end portion 53 of reduced transverse cross section having an upper surface 54, a lower surface 55 and a front wall 56. The front wall 56 is inclined upwardly and rearwardly towards the upper surface 54 and the upper and lower surfaces 54 and 55 diverge rearwardly of the handle portion 51. The upper and lower surfaces 54, 55 have projecting therefrom centrally located outwardly projecting abutment surfaces 57 and 58.
The head portion 52 is provided with an upper surface 59, a lower surface 60, a front wall 61 and a rear wall 62. The upper surface 59 is inclined upwardly and rearwardly in a longitudinal direction of the head portion 52 and is provided with a plurality of tufts 63 which decrease in length the greater the distance of the tufts from the front wall 61 such that the tips of the tufts all lie in a common plane,
The rear wall 62 is provided with a recess 64 extending longitudinally inwardly of the head portion 52. The recess 64 has an end wall 65 inclined upwardly and rearwardly, an upper surface 66 and a lower surface 67, the surfaces 66 and 67 diverging in a rearward longitudinal direction of the head portion 52. The upper and lower surfaces 66 and 67 are provided with recesses 68 and 69 respectively.
The recess 64 and the projection 53 have complementary dimensions such that the projection 53 can be received axially into the recess 64 with an interference fit. When the projection 53 is inserted into the recess 64 such that the front wall 56 of the projection 53 abuts the end wall 65 of the recess 64, the abutment surfaces 57 and 58 of the projection 53 snap in the recesses 68 and 69.
A force applied to separate the handle portion 51 from the head portion 52, is resisted by reaction of the abutment surfaces 57, 58 and the surfaces of the respective recesses 68, 69. However, as the force increases in magnitude, the reaction is overcome and the abutment surfaces 57, 58 are withdrawn from the recesses 68, 69 and the projection 53 withdrawn from the recess 64.
Referring now to FIGURES 13 to 16, there is shown a toothbrush 71 comprising a handle portion 72 and a head portion 73, both being of synthetic plastics material. The head portion 73 is similar to the head portion 52 of the embodiment illustrated in FIGURES 9 to 12 except that the head portion 73 is not provided with a recess but is provided with a pair of transversely spaced parallel projections 74,75 extending rearwardly and longitudinally from a rear wall thereof the projections 74, 75 being of reduced dimension in transverse cross section compared with the transverse cross section of the head portion 73 thereby providing a circumferential shoulder 77. Each of the projections 74, 75 has a dimple 78 therein on adjacent surfaces of the projections 74, 75 remote from the shoulder 77.
The handle portion 72 has a front wall 79 having a recess 80 therein. The recess 80 has an upper wall 81, a lower wall 82 and an end wall 83. The upper and lower walls 81, 82 converge towards the end wall 83. The end wall 83 is provided with a centrally located projection 84.
The arrangement is such that the head portion 73 is connected to the handle portion 72, by inserting the projections 74, 75 into the recess 80. The relative movement causes the projections to be urged towards one another due to the longitudinally rearwardly converging upper and lower walls 81, 82 such that, immediately prior to the shoulder 77 of the head portion 73 moving into abutment with the front wall 79 of the handle portion, the projection 84 is received between the dimples 78 of the projections 74, 75 and is nipped therebetween.
The effect of the projections 74, 75 being squeezed towards one another to engage the projection 84 such that any force tending to separate the head portion 73 from the handle portion 72 is initially resisted.
Referring now to FIGURES 17 to 20, there is shown a toothbrush 85 comprising a handle portion 86 and a head portion 87, each being of synthetic plastics material. The head portion 87 is similar to the head portion 52 of the toothbrush 50 shown in FIGURES 9 to 12 except that a recess 88 in a rear wall 89 of the head portion 87 is provided with an inwardly extending circumferential bead 90 and the recess 88 has a projection 91 extending from an inner wall thereof outwardly of the rear wall 89 in a longitudinal direction of the head portion 87. The projection 91 tapers in a direction away from the rear wall 89.
The handle portion 86 has a front wall 92 having a recess 93 therein, the recess tapering in a direction inwardly of the handle portion 86 from the front wall 92. The handle portion 86 is provided with an outer circumferential bead 94 located adjacent the front wall 92.
The arrangement is such that when the projection 91 is inserted into the recess 93, the bead 94 is forced under the bead 90 and is retained therein, as shown in FIGURE 19. When a force is applied to separate the handle portion 86 from the head portion 87 separation is initially resisted by the beads 90 and 94.
Referring now to FIGURES 21 to 24, there is provided a toothbrush 100 comprising a handle portion 101 and a head portion 102. The handle portion 101 is similar to the handle portion 51 of the toothbrush 50 shown in FIGURES 9 to 12 and the head portion 102 is similar to the head portion 52 of the toothbrush 50. With the toothbrush 100, however, the head portion 102 is provided with a recess 103 having an upper wall 104 , a lower wall 105 and an end wall 106. The recess also is provided with a cavity 107 extending inwardly below the end wall 106. The recess 103 is provided with a single dimple 108, which is located on the upper wall 104 of the recess.
The handle portion 101 is provided with an elongate projection 109 corresponding to the projection 53 of the handle portion 51 of the toothbrush. However, the projection 109 is provided with a forward extension 110. The projection 109 also is provided with a single abutment surface 111 which is located on an upper surface 112 of the projection 109. The projection 109, including the extension 110 and the abutment surface 111, in longitudinal cross section is complementary in shape to the shape of the recess 103, including the cavity 107 and the dimple 108, so that when the projection 109 is inserted longitudinally in the recess 103, the projection is retained therein by interference fit, as with the toothbrush 50.
In each of the embodiments shown in the accompanying drawings, the handle portion and the head portion are interengaged by relative movement of the handle portion and the head portion in directions parallel to a longitudinal axis the handle portion. However, it will be appreciated that the longitudinal axis of the recess in the handle portion or the head portion and the longitudinal axis of the projection on the head portion or handle portion adapted to be received in the recess, may extend at an angle to the central longitudinal axis of the handle portion or the head portion.
It will also be appreciated that with each of the embodiments shown in the accompanying drawings, the recess may be provided in the handle portion and the projection for co-operating therewith provided on the head portion or, alternatively, the recess may be provided in the head portion and the projection on the handle portion.

Claims

1. A brush comprising a head portion having a plurality of tufts extending therefrom, a handle portion, the portions having interengagable formations whereby the head portion is adapted to be removably carried by the handle portion and when so carried to be movable relative to the handle portion in a predetermined direction, and shap engagement means for resisting a force applied in the said direction to separate the portions one from other, the arrangement being such that the snap engagement means resists said force until a component of the force exceeds a predetermined magnitude causing release of the snap engagement means to permit separation of the said portions.

2. A brush as claimed in Claim 1 wherein the interengagable formations comprise a plug and a socket.

3. A brush as claimed in Claim 2 wherein the plug and socket are of complementary configurations.

4. A brush as claimed in Claim 2 or Claim 3 wherein the snap engagement means comprises complementary abutment surfaces carried by the plug and socket respectively.

5. A brush as claimed in Claim 4 wherein one of said abutment surfaces is located in the socket.

6. A brush as claimed in any one of Claims 2 to 5 wherein the socket is provided with a cavity which tapers in a direction inwardly of the recess.

7. A brush as claimed in Claim 5 wherein the plug comprises a pair of transversely spaced elongate members adapted to engage therebetween .said abutment surface in the socket.

8. A brush as claimed in any one of Claims 2 to 6 wherein a wall of the socket is inclined inwardly towards a longitudinal axis of the socket.

9. brush as claimed in Claim 8 wherein the socket is open in a direction transverse to the said longitudinal axis and in a direction parallel to said longitudinal axis.

10. A brush as claimed in any one of Claims 2 to 9 wherein the socket is in the heed portion.