Floor nozzle for electric cleaner

A floor nozzle for vacuum cleaner comprising: a floor nozzle body in which an agitator and a drive source are incorporated, the agitator includes a rotor provided on its outer peripheral surface with flexible lips made of polyurethane rubber added with talc as a reinforcing agent so as to have a rubber hardness of 50 to 70, and blended with 0.1 to 0.5% of a coloring agent.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an agitator used in a floor nozzle for a 
vacuum cleaner. 
2. Description of the Prior Art 
In an agitator of this type, a brush is implanted along a circumferential 
surface of a rotor. Dust on a surface to be cleaned, for example, a carpet 
are scraped by the brush and are introduced into the floor nozzle by the 
suction of the electric cleaner. However, string-like dust such as lint is 
entrained around the brush and becomes entangled around the overall 
agitator to degrade its desired function. Also, the removal of the string 
is troublesome and labourious. 
In order to cope with this problem, instead of the brush implanted along 
the circumferential surface of the rotor of the agitator, there has been 
proposed a structure in which lips each having a number of projections on 
at least one surface thereof and made of molding materials such as soft 
vinyl chloride resin or the like, or flexible materials such as 
chloroprene rubber or the like are provided around the circumferential 
surface of the rotor. With this arrangement, it has been possible to 
eliminale a problem of lint entangled around the circumferential surface 
of the rotor, but the lips which are made of soft chloride vinyl resin 
wear out in a relative short time. Thus, there is a problem in durability. 
Also, if the lips are made of chloroprene rubber or the like, carbon black 
which has been added thereto in order to reinforce the rubber contaminates 
the floor surface with a black color. Thus the prior art cleaner has 
suffered from various problems. 
SUMMARY OF THE INVENTION 
In order to overcome the above-noted defects, according to the present 
invention, lips made of molding material in which talc is blended serving 
as both reinforcement and friction reducing agent with vulcanized 
polyurethane rubber are formed on the circumferential surface of a rotor 
to form an agitator. 
A number of projections are formed on at least one surface (which extends 
in the rotational direction) of the lips of the agitator. In addition, the 
lips are formed of molding materials such as vulcanized urethane rubber or 
the like having excellent flexibility and repulsive property. Therefore, 
the lips are well fit for a surface to be cleaned when the lips are 
brought into contact with the surface. The lips serve to well rub the 
surface to be cleaned. As a result, dust is freed from the surface to be 
cleaned and is sucked into a floor nozzle body with a high degree of 
efficiency under suction of the cleaner and the restoring force of the 
lips. Several projections are formed on a tip end portion of each lip, 
which are rotated in sliding contact with the surface to be cleaned, such 
as a carpet, under pressure. Due to the action of the talc or the like 
added to the lip as a reinforcement or friction-reducer and the usage of 
the vulcanized polyurethane rubber excellent in durability against 
friction, it is possible to keep sufficient dust collecting performance 
and a long service life without contamination of the floor with black 
agents. 
Also, since the hardness of each lip is set to a value from 50 to 70, when 
the lip is brought into contact with the surface to be cleaned, the 
suitable fit phenomenon occurs in an optimum condition on the surface, to 
thereby effectively rub the surface. Therefore, the dust collecting 
performance on the surface to be cleaned is further enhanced. Furthermore, 
since an extremely small amount of rubber coloring agent such as carbon 
black to an extent of 0.1 to 0.5% is added into the vulcanized 
polyurethane rubber blended with talc to give a slight color to the 
rubber, there is no fear that the floor surface would be contaminated by 
such a coloring agent. Spotted burns or contamination generated during the 
molding operation would not be remarkable to effectively enhance an 
aesthetic appearance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be described with reference to the 
accompanying drawings. 
Referring now to FIGS. 1 to 4 there is shown a floor nozzle body 7 composed 
of upper and lower body members 9 and 10 which are coupled together 
through the intermediary of a bumper 8. A suction chamber 12 having a 
lower opening as a suction port 11 is formed in a front inner portion of 
the nozzle body 7, and a turbine chamber 13 is formed in a rear inner 
portion of the nozzle body 7. The turbine chamber 13 is separated from the 
suction chamber 12 by a partition wall 14. Also, its rear portion having 
an opening 15 is formed in an arcuate shape. An agitator 16 is arranged in 
parallel with the suction chamber 12 within the suction chamber 12. A pair 
of bearings 17 are provided for the agitator 16 on opposite side walls of 
the suction chamber 12. A stationary brush 18 is arranged in the rear of 
the suction port 11 in parallel therewith. Wheels 19 and 20 are provided 
to front and rear portions of the floor nozzle body 1, so as to obtain a 
predetermined space between the floor nozzle body 1 and the floor to be 
cleaned. 
A substantially semicylindrical suction joint 21 is slidably and rotatably 
arranged on the inner rear surface of the turbine chamber 13. A floor 
nozzle pipe 24 is rotatably fitted on a cylindrical connection port 22 
projected from a part of the circumferential wall of the suction joint 21 
through the intermedialy of a ring 23. Also, an extension tube which is 
communicated to the suction side of the vacuum cleaner through a hose is 
detachably connected to the floor nozzle pipe 24. 
A turbine 25 is arranged in the turbine chamber 13 and partially surrounded 
by the suction joint 21 along the circumference of the turbine. A shaft 26 
is integrally formed with the turbine 25 and passed through the suction 
joint 21 on one side. 
A power transmission belt 27 is used to transmit the rotation of the 
turbine 25 to the agitator 16 through a pulley 28. 
Also, the turbine 25 is set aside to the belt 27 within the turbine chamber 
13. Vent holes 29 and 30 are formed in the partition wall 14, one vent 
hole 29 being confronted by the lower half portion of the turbine 25 and 
the other vent hole 30 being not confronted by the turbine 25 but directly 
by the connection port 22 of the suction joint 21. 
A switching lever 31 has a shielding plate 32 extending from a part of the 
switching lever 31, and formed therein with an opening 33 adapted to be 
selectively communicated with one of the vent ports 29, 30. 
In the foregoing structure, when the switching lever 31 is slid to the 
right in FIG. 2 so as communicate the opening 33 of the shielding plate 32 
with the vent hole 29, the suction air that has been introduced from the 
suction port 11 through the suction chamber 12 and the vent port 29 
collides against the turbine 25. Subsequently the air flows through the 
connection port 22 of the suction joint 21, the floor nozzle pipe 24, the 
extension tube and the hose to the vacuum cleaner. Therefore, the turbine 
25 is rotated and its rotational power is transmitted to the agitator 16. 
It should be noted that the agitator 16 is formed with spiral lips 35 along 
the longitudinal outer direction of the rotor 34. Each lip 35 is made of 
flexible material such as vulcanized urethane rubber and is provided with 
a number of projections 36 on at least one surface thereof (surface in the 
rotational direction). 
When the agitator 16 is rotated in the clockwise direction as shown in FIG. 
5, the lip 35 is shifted in the opposite direction to the rotational 
direction at the position contact with the surface to be cleaned and is 
deformed in conformity with the surface to be cleaned. Thereafter, the lip 
35 skips relative to the surface to be cleaned while rubbing the surface. 
At this time, the dust is rubbed by the projections 36 of the lip so as to 
be removed away from the surface to be cleaned. 
The free dust is effectively introduced into the floor nozzle body 7 by the 
suction force of the vacuum cleaner and the repulsive force effected when 
the lip 35 is restored in the radial direction (due to the flexibility and 
centrifugal force). 
The lip 35 is used to interrupt the flow of the air from the front side 
when it is brought into contact with the surface to be cleaned, whereby 
the suction force of the vacuum cleaner is concentrated on the surface to 
be cleaned and acts thereon with the assistance of the lip 35. 
Also, since the lip 35 is in the form of a band, it is possible to prevent 
strings or the like from being entangled around the lip. 
As described above, the lips 35 each mounted in the circumferential and 
longitudinal direction of the rotor 34 serve to remove dust away from the 
surface to be cleaned and to impart the repulsive action to the dust. 
These lips are the basic members for determining the dust collection 
performance. 
During the use of the floor nozzle, the agitator is rotated at a high speed 
of 3,000 to 4,000 rpm, is brought into press contact with the carpet 
surface and is reciprocatingly moved back and forth. The agitator must 
have a durability over five years under the above-mentioned use. It is 
also necessary to ensure the durable service life of the lips over 500 
hours. In order to meet this requirement, the lips should have the 
following properties: 
I. The melting resistance and wear resistance must be considerably high. 
II. The lips must fit the surface to be cleaned and their surfaces have the 
function to rub the carpet surface. The lips need the repulsive property 
and restoring property. The lips must have flexibility and high repulsive 
performance. 
III. The lips do not have contamination property to the floor surface. 
It would be possible to use the molding material such as natural rubber, 
chloroprene rubber, nitrile rubber or the like for the lips that meet the 
above-described requirement. However, if white carbon is used as 
reinforcement for these general rubbers, the requirements would not be 
met. Thus, it is necessary to use carbon black having a high reinforcement 
effect. In this case, however if the lips are rubbed on the floor surface, 
the black contamination phenomenon would be generated on the floor to 
raise a serious problem. 
According to the invention, vulcanized polyurethane rubber is used as the 
molding material in order to meet all the requirements. Since the 
vulcanized polyurethane rubber sufficiently meets the practical strength 
without using carbon black as the reinforcement, there is no fear that the 
floor surface would be contaminated by black color. However, since the 
lips needs melting resistance and friction resistance and must be used in 
a particularly severe condition, 30 to 60 parts of talc is added into 100 
parts of vulcanized polyurethane rubber in order to reduce the friction 
coefficient and to enhance the reinforcement effect, thereby ensuring long 
service life of the floor nozzle over five years and the durability of the 
lips over 500 hours. 
It is a matter of course to ensure the durability of the floor nozzle. It 
is one of the most important factors to increase the dust removing 
performance on the surface to be cleaned. For this reason, the function of 
the lips mounted on the surface of the rotor of the agitator is important. 
When the lips are brought into contact with the surface to be cleaned, the 
lips must fit the surface to free dust away from the surface and to 
introduce the freed dust into the floor nozzle body by the restoring force 
of the lips. Thus, the lips must have high elasticity, a high creep 
characteristic and high flexibility. The hardness thereof is preferably in 
a range of 50 to 70. This hardness is measured under Durometer hardness, 
shore A of ASTM D-2240. 
Also, if the lips are white, the molded surfaces thereof are liable to be 
inferior in appearance due to spotted burrs, contamination or the like, 
causing the non-acceptable product rate. To increase polyurethane rubber 
suffers from such a disadvantage that the color thereof is changed by 
ultraviolet rays. Therefore, for example, 0.1 to 0.5% carbon black or the 
like is added as a coloring pigment to color the rubber, whereby the 
appearance defect rate is considerably reduced and the weather color 
change may be prevented with no contamination of the floor surface. 
The examples of the blending rates of the molding material and vulcanized 
polyurethane rubber for the lips according to the invention will be listed 
below: 
______________________________________ 
Blending amount 
Blended Agents (Parts) 
______________________________________ 
polyether modified 
urethane rubber 
Takenate E-3000 100 
talc, crown talc 30 to 60 
titanium oxide 5 to 15 
zinc stearin acid 0.1 to 1.0 
coloring carbon FEF class 
0.1 to 0.5 
vulcanization accelerator M 
0.5 to 2.5 
vulcanization accelerator DM 
0.5 to 2.5 
vulcanization accelerator PZ 
0.5 to 2.0 
active trimethyrol propane, 
trimethacrylate 0.5 to 2.0 
sulfur 200 meshed powder 
1.0 to 1.5 
Vulcanization Condition 
temperature: 110 to 150.degree. C. 
period: 8 to 30 minutes 
pressure: 20 to 50 kg/cm.sup.2 
______________________________________ 
The physical property of the vulcanized polyurethane rubber used for the 
lips molded under the above-described condition is as follows (ASTM 
D-2240, Durometer Hardness, Shore A): 
tensile strength: 200 to 300 kg/cm.sup.2 
elongation hardness: 500 to 700% 
rubber hardness: 55 to 65 
shearing strength: 30 to 50 kg/cm.sup.2 
friction index [(decreased weight/original total weight)x100]: 0.1 to 3.0% 
As has been apparent from the above description, according to the present 
invention, the vulcanized polyurethane rubber is used as a molding 
material for the lips provided in the longitudinal direction of the rotor 
circumferential surface of the agitator, and 30 to 60 parts of talc is 
added to the polyurethane rubber (100 parts) as additives. 
As a result, the vulcanized polyurethane rubber satisfies the practical 
strength with no use of carbon black which is essential in natural rubber 
and chloroprene rubber. Thus, there is no fear that the floor surface 
would be contaminated with black. Also, the lips requires high melting 
resistance and wear resistance and must endures under severe conditions in 
use. Therefore, although it is sufficient to have wear resistance alone 
for the vulcanized polyurethane rubber alone, the present invention 
proposes that talc is added to vulcanized polyurethane rubber thereby 
considerably reducing the friction coefficient and surely enhancing the 
service life. 
The hardness of the lips is set in the range of 50 to 70 (ASTM D-2240, 
Durometer Hardness, Shore A). As a result, when the lips are brought into 
contact with the surface to be cleaned, the lips fit the surface under an 
optimum condition to remove the dust away from the surface and to 
introduce, with ease, the removed dust by the restoring force of the lips 
so as to considerably enhance the dust removing efficiency. 
Since the vulcanized polyurethane rubber which is white and added with the 
talc is used as the molding material for the lips, the lips are inferior 
in resistance of weather discoloration such as yellow discoloration by 
ultraviolet rays, and it requires severe management in molding ability 
since the appearance defect rate is liable to be increased due to spotted 
burns or contamination during the molding process. However, according to 
the invention a small amount of coloring agent such as carbon black is 
added by 0.1 to 0.5% to color the lips slightly. This does not cause the 
floor contamination and makes it possible to improve the above-mentioned 
disadvantages.