Figure 1 discloses a preexisting apparatus for making (finishing)
toothbrushes. Pairs of toothbrushes 10 are secured to blocks 12. The toothbrushes
are in nearly their final state of manufacture at this point with bristles secured
to the heads of the toothbrushes. A chain 14 periodically advances blocks 12 in
the direction of an arrow 16.
A group of five cutters 18 are each used to trim or cut a subgroup
of bristles on each brush to their specified length. A group of seven end-rounders
20 are used to round off the cut free ends of various subgroups of the bristles.
Chain 14 advances all of toothbrushes 10 until they are properly positioned over
a respective cutter or end-rounder.
A plow or fork (not shown) is then inserted into the bristles of some,
but not all, of the toothbrushes which are adjacent to a cutter or end-rounder.
The plow bends some of the bristles on a brush out of the way so that other bristles
on the brush can be trimmed or end-rounded as the case may be. A platform (support)
22 is then raised to bring the cutters and end-rounders into contact with the bristles
which are to be trimmed or end-rounded. It takes about .75 seconds to raise all
the cutters and end-rounders.
After the bristles are trimmed or end-rounded, platform 22 is lowered
to distance the cutters and end-rounders from the bristles. Chain 14 then advances
to move the toothbrushes to the next cutter or end-rounder in the finishing process.
Although not shown, after the toothbrushes receive a final-end-rounding at the right-most
end-rounder in Fig. 1, they are removed from chain 14 and packaged. These toothbrushes
are replaced in blocks 12 by new unfinished toothbrushes which have yet to be trimmed
and end-rounded.
A problem with this arrangement is that during the time platform 22
is being raised and lowered, no end-rounding is being done on the bristles. Further,
while chain 14 is advancing the toothbrushes into and out of a certain end-rounding
station, no end-rounding is being done on the bristles. As a result, more aggressive
end-rounding must be done during the limited time available to end-round the bristles.
This requires plows (forks) to be inserted into the bristles at five of the seven
end-rounding stations.
The present invention is directed to overcoming one or more of the
problems set forth above. Briefly summarized, according to one aspect of the present
invention, an apparatus for making toothbrushes includes an end-rounder for rounding
the free ends of bristles secured to a head of a toothbrush. The end-rounder is
secured to a support, the support being substantially fixed against movement.
According to another aspect of the invention, an additional end-rounder
is included for rounding the ends of bristles secured to the head of the toothbrush.
The additional end-rounder is secured to an additional support. The additional support
is moveable alternately towards or away from the toothbrush to move the additional
end-rounder towards or away from the toothbrush.
According to a further aspect of the invention, a cutter is provided
for trimming the length of bristles on the toothbrush head prior to the ends of
these bristles being rounded by the end-rounder. The cutter is moveable alternately
towards or away from the toothbrush to move the cutter towards or away from the
toothbrush.
These and other aspects, objects, features and advantages of the present
invention will be more clearly understood and appreciated from a review of the following
detailed description of the preferred embodiments and appended claims, and by reference
to the accompanying drawings.
- FIG. 1 is a schematic side view of a pre-existing apparatus for making/finishing
toothbrushes;
- FIG. 2 is a schematic side view of an apparatus according to the invention for
making/finishing toothbrushes;
- FIG. 3 is a bottom view of a bristle finishing fork inserted into a group of
bristles;
- FIG. 4 is a sectional view of Fig. 3 taken along the lines 4-4 of Fig. 3;
- FIG. 5 is a sectional view of a cutter as looking into the paper on which Fig.
2 lies;
- FIG. 6 is similar to Fig. 5 but also showing an end-rounder in operating position;
and
- FIG. 7 is a perspective view of a bristle pattern on a toothbrush which can
be made by the current invention.
Beginning with FIG. 2, reference numerals will be used that are similar
to the reference numerals in Fig. 1 for those elements that are essentially the
same. Pairs of toothbrushes 10 are secured to blocks 12. The toothbrushes are in
nearly their final state of manufacture at this point with tufts of bristles secured
to the heads of the toothbrushes. The bristle tufts may have various heights and
orientations at this point.
A chain 14 periodically advances blocks 12 in the direction of an
arrow 16. Each advance of chain 14 takes about .5 seconds. The chain stops moving
when a pair of toothbrushes are adjacent to each of five cutters 18 and seven end-rounders
20(a)-(g). The cutters and end-rounders are constantly running. The bristles on
each toothbrush adjacent a cutter or end-rounder are facing down towards the cutter
or end-rounder.
Referring to Figs. 3 and 4, a bristle finishing fork (or plow) 30
is now inserted opposite the direction of an arrow 31 into bristles 32 between head
34 of the toothbrush and a respective one of the cutters or end-rounders. The fork
bends a first sub-group of bristles 36 to the side while allowing a second sub-group
of bristles 38 to project through a gap 40 in the fork. This arrangement allows
ends 40 of bristles 38 to be cut or end-rounded as the case may be while preventing
ends 42 of bristles 36 from being cut or end-rounded.
Forks are used on the first three cutters the toothbrush encounters
but not the last two cutters. This is the same as for the Fig. 1 apparatus. Forks
are only required if it is necessary to prevent some bristles from being cut or
end-rounded while other bristles are cut or end-rounded. This all depends on the
final topography of the bristles desired.
Next, a pneumatic piston 44 is actuated to pull a piston rod 46 into
the piston. This causes a cam follower 48 to move along a cam path 50. Cam follower
48 is also linked to a second cam follower 52 which likewise moves along another
cam path 54. The motion of the cam followers causes a support 56 to move up about
7mm in about .6 seconds. The five cutters and 1st end-rounder are connected
to support 56 and likewise move up with the support. This motion causes designated
bristles to come into contact with the cutters and end-rounders.
Turning now to Fig. 5, the operation of the cutters will be explained.
Each cutter 18 includes four rotating trimmer blades 60 and a stationary counter
blade 62. The act of raising support 56 causes bristles designated for cutting to
move relative to cutter 18 in the direction of an arrow 64. After support 56 stops
moving up, all of the cutters 18 are moved back and forth together in the direction
of double-headed arrow 64. Each movement is about 2.5 inches and the cutters make
about 5 cycles back and forth. This movement of the cutters allows the designated
bristles of both toothbrushes presented to each cutter to be properly trimmed. The
cutting operation takes about 4 seconds. The orientation and/or position of a cutter
can be adjusted to alter the angle of cut on the bristles.
Referring to Fig. 6, end-rounder 20(a) is also raised on support 56.
End rounder 20(a) includes a partial spherical surface 66 which has a roughened
finish for abrading and rounding the free ends of bristles 38. The end-rounder is
rotated in the direction of an arrow 68 about an axis 70. Axis 70 is also rotated
about axes 72 and 74. The resultant motion results in what is called an orbital
end-rounder. Further details on this type of end-rounder and on fork 30 can be found
in US Patent 5,593,213.
The remaining end-rounders 20 (b)-(g) are not connected to support
56 and so do not move up or down with the support. Each end rounder 20(b)-(g) is
connected to an additional support 76 which is substantially fixed against movement.
As such, these six end-rounders are already in position to end-round when chain
14 starts moving the toothbrushes. After end-rounding and cutting is complete, piston
44 is actuated to lower support 56 and thus lower the five cutters and the first
end-rounder. This lowering operation takes about .5 seconds.
Although not shown, after the toothbrushes receive a final-end-rounding
at the right-most end-rounder 20(g), they are removed from chain 14 and packaged.
These toothbrushes are replaced in blocks 12 by new unfinished toothbrushes which
have yet to be trimmed and end-rounded.
There are a number of advantages to thus fixing the last six end-rounders
in position. End-rounding can now be done while chain 14 is moving toothbrushes
both into and out of a particular end-rounder, as well as during substantially all
of the time support 56 is being raised and lowered. This adds about 1.5 more seconds
of end rounding for each toothbrush at each of the six fixed end-rounders. Thus
about nine more seconds of end-rounding are done on each brush. This additional
end-rounding times allows end-rounding to be done less aggressively. As a result,
none of end-rounders (b)-(g) require forks 30 to be used, resulting in a cost savings.
In the system of Fig. 1, four of these six end-rounders required forks to be used.
End-rounder 20(a) still requires a fork because it is end-rounding the shortest
bristles on the toothbrush.
Another advantage is that support 56 can be raised faster because
it is lifting only one end-rounder instead of seven end-rounders. As a result, support
56 can be raised in about .2 seconds.
Fig. 7 shows a toothbrush 80 which can be made by the method and apparatus
described above. The bristle pattern is that of the Advantage® toothbrush sold
by Oral-B®. Toothbrush 80 includes a head 82 from which extends a group of bristle
tufts 84 known as a "power tip". The top surface of tufts 84 angles down towards
head 82. Another group of bristle tufts 86define a "V" or "U" shaped grove 88 known
as an "action cup".
