Upright vacuum cleaner

An upright vacuum cleaner comprising a main body having a suction opening in the lower surface of its front portion and a handle body connected to a rear portion of the main body and extending upward. The main body is pivotally movable in the form of a seesaw as supported by contact portions on the main body positioned to the rear of the suction opening. The handle body is pivoted to the main body shiftably between an upright position and an inclined position and is provided on its lower end with propelling wheels which are positioned rearwardly away from a line perpendicular to a floor surface and passing through the pivot point. The main body front portion, namely the suction opening, is held raised from the floor surface while the handle body is in its upright position but comes into contact with the floor surface when the handle body is inclined through an angle suitable for use.

The present invention relates to a vacuum cleaner, and more particularly to 
an upright vacuum cleaner including a main body having a suction opening 
in its lower surface and movable on a floor surface and a handle body 
extending upward from the main body. 
Upright vacuum cleaners are frequently left in idle operation during use as 
when the user shifts an article of furniture. If the cleaner is allowed to 
stand in this state for a prolonged period of time, the electric fan will 
become overheated to produce thermal deformation in resin parts such as 
the main body since the suction opening is held closed with the surface to 
be cleaned such as floor surface or carpet thereon (hereinafter referred 
to simply as "floor surface"). Furthermore, a rotary brush and/or a 
beating element such as a beater, if provided at the suction opening, will 
then stroke or beat the same portion of the floor surface, causing damage 
to the floor surface as by picking loops or tufts from a carpet. If the 
rotary brush is used on a floor surface provided by polyester fibers or 
the like having low heat resistance, the rotation of the brush on the same 
portion produces frictional heat which would melt some fibers to lock the 
brush, possibly breaking the drive belt for the rotary brush. 
To overcome these problems, upright vacuum cleaners have already been 
proposed which are so designed that when a handle body is raised to an 
upright position relative to the cleaner main body, namely to the floor 
surface, to interrupt the cleaning operation, the suction opening is 
automatically moved away from the floor surface in operative relation to 
the movement of the handle body, as disclosed, for example, in U.S. Pat. 
Nos. 3,676,892 and 3,854,164. Like the conventional cleaner to be 
described later with reference to FIG. 5, such cleaners nevertheless have 
a complex construction including a lever mechanism and require many steps 
of assembling a large number of parts, so that they are costly to make and 
involve difficulties in ensuring a stable operation over a prolonged 
period of time. 
The main object of this invention is to provide an upright vacuum cleaner 
which has a simple construction with a reduced likelihood of troubles and 
in which a suction opening is automatically movable away from the floor 
surface when a handle body is raised to an upright position relative to 
the floor surface so that the suction opening will not be closed for a 
long time, the suction opening portion further being automatically movable 
away from the floor surface together with a rotary brush or a beating 
element for the floor surface when provided with the brush or the element, 
for the protection of the floor surface. 
To fulfil this object, the present invention provides an upright vacuum 
cleaner comprising a main body having a suction opening in the lower 
surface of its one end and contact portions adapted for contact with a 
floor surface and positioned on one side of the suction opening remote 
from said one end, the main body being pivotally movable on the contact 
portions, and a handle body including a lower end portion pivoted to the 
other end of the main body turnably about a horizontal axis. The handle 
body is therefore movable between an upright first position and a second 
position in which the handle body is inclined at a desired angle. 
Propelling wheels mounted on the lower end portion of the handle body are 
positioned away from a line perpendicular to the floor surface and passing 
through the horizontal axis when the handle body is in its upright 
position. 
According to an embodiment of this invention, the contact portions are 
front wheels mounted on the main body. This renders the main body smoothly 
movable and eliminates the wear on the contact portions. 
Further according to a preferred embodiment of this invention, the suction 
opening is provided with auxiliary means such as a rotary brush, or a 
beater or like impact imparting element for releasing dust from the floor 
surface. 
The auxiliary means can be driven by the rotary shaft of an electric fan 
housed in the handle body coaxially with the horizontal axis, the rotary 
shaft extending through the handle body into the main body. 
Notwithstanding that the handle main body houses a dust collector 
including the electric fan and a dust collecting bag, the auxiliary means 
within the main body can be driven by the same single motor as used for 
the fan.

Before describing an embodiment of the present invention, the construction 
of a conventional vacuum cleaner referred to above will be described with 
reference to FIG. 5. While the cleaner is used in the usual position, the 
main body 100 is movable on the floor surface as supported by rear wheels 
101 on the main body. The front lower surface of the main body 100 is in 
contact with the floor surface. A handle body 102 is pivoted to a rear 
portion of the main body 100. When cleaning, the user holds the handle 
body 102 in the inclined position indicated in the solid line and moves 
the main body 100. When the handle body 102 is brought to its upright 
position indicated in the phantom line for an interruption of the cleaning 
operation, a boss 103 on the handle body 102 comes into contact with a 
lever 104, depressing a front wheel 105 on the front end of the lever 104. 
Since the lever 104 is supported by a pin 106 on the main body 100, the 
resulting counteraction raises the front portion of the main body 100 
after the front wheel 105 has been brought into contact with the floor 
surface, whereby the suction opening or rotary brush 107 is lifted from 
the floor surface. Thus the conventional cleaner has a complex 
construction which is liable to malfunction, for example, owing to the 
deformation of the lever. 
This invention, which has overcome such a drawback, will be described with 
reference to the embodiment shown in FIGS. 1 to 4. The main body 1 of the 
cleaner is formed with a substantially rectangular suction opening 1a in 
the lower surface of its front portion and is movable on a floor surface, 
namely the surface to be cleaned. With the present embodiment, the suction 
opening 1a is provided with auxiliary means 2 for releasing dust from the 
floor surface. The illustrated auxiliary means 2 comprises a rotary brush 
23 on one half of the peripheral surface of a rotary drum 22 and a beater 
24 on the other half thereof, the drum 22 being fixedly mounted on a 
rotary shaft 21 rotatably supported on the main body 1. The brush 23 is 
composed of bristles set into the peripheral surface in two rows spaced 
apart from each other circumferentially of the drum 22 and extending 
obliquely with respect to the axis of the drum. The beater 24 includes two 
projections of triangular cross section similarly spaced apart and 
extending obliquely of the drum axis. The beater 24 gives impact to a 
carpet or the like to release dust therefrom, while the brush 23 removes 
dust from the floor surface. The dust is entrained in a stream of suction 
air. A handle body 3 comprises a box-shaped dust collector 6 positioned in 
its lower portion and housing an electric fan 4 and a dust bag 5 or the 
like and a rodlike handle 7 extending upward from the dust collector 6. 
The handle body 3 is supported, at a lower end portion, by pivots 8 on a 
rear portion of the main body 1 and is turnable about a horizontal axis. 
When using the cleaner of the construction described above, the user holds 
the free end of the handle 7 and moves the main body 1 back and forth for 
cleaning, with the handle body 3 inclined rearward. After cleaning, the 
handle 7 is raised to bring the handle body 3 to a substantially vertical 
upright position. In this position the cleaner is stored or allowed to 
stand. 
The electric fan 4 is arranged concentrically with the pivots 8 for 
supporting the handle body 3 on the main body 1. As seen in FIG. 3, the 
rotary shaft 4a of the fan 4 extends through the handle body 3, namely the 
pivot 8, into the main body 1. A belt 9 reeved around the fan shaft 4a and 
a pulley 25 on the rotary drum shaft 21 delivers the torque of the fan 4 
to the drum 22. The dust released from the floor surface by the auxiliary 
means 2 and introduced into the main body 1 through the suction opening 1a 
as entrained in a suction air stream is conducted to the dust bag 5 of the 
dust collector 6 by way of a flexible hose 10. The hose 10 has one end in 
communication with the suction opening 1a via the interior space of the 
main body 1 accommodating the auxiliary means 2 and the other end 
communicating with the interior of the dust collector 6. 
The dust is captured by the dust bag and separated from the air stream 
flowing through the opening 1a and hose 10, allowing clean air alone to 
flow out from the cleaner via an unillustrated outlet. 
Indicated at 11 are front wheels mounted on the bottom of the main body 1 
on the rear side of the suction opening 1a, and at 12 rear wheels mounted 
on a lower end portion of the handle body 3. The main body 1 is movable on 
the floor surface by these wheels 11 and 12. The front wheels 11 and the 
rear wheels 12 are so arranged as to fulfil the following positional and 
dimensional requirements. 
The front wheels 11 are attached to the lowermost portion of the main body 
1, such that the main body is pivotally movable upward or downward on the 
front wheels 11 like a seesaw. The position of the rear wheels 12 on the 
handle body 3 is so determined that when the handle body 3 is in its 
upright position substantially perpendicular to the floor surface, the 
pivots 8 are spaced from the floor surface by the shortest distance to 
position the rear portion of the main body 1 at a lower level, thus 
positioning the main body 1 in a rearwardly downwardly inclined posture, 
the position of the rear wheels 12 further being such that when the handle 
body 3 is inclined by the handle 7 through an angle generally suitable for 
use, the pivots 8 are at the largest distance from the floor surface so 
that the main body 1 is in a forwardly downwardly inclined position with 
the main body front portion at a lower level. Stated more precisely, the 
rear wheels 12 are positioned away from a line perpendicular to the floor 
surface and passing through the axis of the pivots 8 when the handle body 
3 is in its upright position, whereas when the handle body 3 is in its 
inclined position for use, the rear wheels 12 are located close to a 
position immediately below the pivots 8, namely close to the perpendicular 
line. The rear wheels 12 mounted on the rear end portion of the handle 
body 3 must fulfil these requirements. The suction opening 1a of the main 
body 1 is adapted to be positioned close to the floor surface while the 
handle body 1 is in its inclined position for cleaning operation with the 
main body 1 in its forwardly downwardly inclined position so that all the 
dust on the floor can be removed. 
The cleaner of this invention will be used in the following mode as 
illustrated in FIG. 4. Since the handle body 3 is pivotally movable on the 
pivots 8 relative to the main body 1, the main body front portion is held 
in its lowered position by gravity as supported by the front wheels 11 on 
the floor surface during cleaning. The opening portion 1a, which is close 
to the floor surface as indicated at A.sub.1 in FIG. 4 or in intimate 
contact therewith, assures a very efficient cleaning operation. The main 
body 1, being upwardly movable on the pivots 8, will have no difficulty in 
passing over a cigarette stub or like obstacle on the floor, if any. Thus 
a continuous cleaning operation can be carried out free of any trouble. 
Not infrequently the user will interrupt the cleaning operation to arrange 
a table, chair or the like, to remove dust from furniture or to answer a 
telephone call, leaving the cleaner on the floor surface for idle 
operation. In such an event, the handle 7 is raised to bring the handle 
body 3 to its upright position indicated in the phantom line in FIG. 4. 
With this movement of the handle body 3, the rear wheels 12 turn from the 
position immediately below the pivots 8 rearward around the pivots 8, 
consequently lowering the level of the pivots 8 relative to the rear 
wheels 12 and reducing the distance between the pivots 8 and the floor 
surface since the rear wheels 12 are in contact with the floor surface at 
all times to support the cleaner. As a result, the main body 1, which is 
supported also by the front wheels 11, turns on the front wheels 11 to 
bring its rear portion to a lower level. The suction opening 1a and the 
auxiliary means 2 in the front portion of the main body 1 therefore rise 
from the floor surface as indicated at A.sub.2. 
With the main body thus positioned, the continued sucking action will not 
produce thermal deformation or like trouble that would occur when the 
suction opening is held closed for a prolonged period of time. Whereas the 
rotary brush, if allowed to rotate on the same portion of the surface to 
be cleaned (especially of carpet), will pick loops or tufts therefrom or 
otherwise damage the surface, such a trouble is avoidable. When a carpet 
of chemical fibers (especially of polyester, nylon or the like having low 
resistance to heat) is continuously brushed on the same portion, the 
resulting frictional heat is likely to melt some fibers which would in 
turn lock the brush, possibly breaking the drive belt for the brush, but 
such objection is similarly avoidable. 
The cleaner of this invention is extremely simple in construction and 
includes none of sliding portions that would encounter increased 
resistance due to deposition of dust as is the case with usual cleaners. 
This ensures a trouble-free operation. Since there is no need to use a 
particular part of especially high strength, the cleaner can be fabricated 
with a stable quality. 
Although the embodiment described above includes a rotary brush and a 
beater at the suction opening and incorporates suction means, the cleaner 
may be provided with the brush or beater only or with a suction opening 
having neither of these members. The suction means may be provided as a 
separate unit communicating with the suction opening through a hose. The 
beater can be of any other type. The front wheels mounted on the main body 
bottom of the embodiment may be replaced by some other members for 
supporting the main body and permitting inclination of the main body, such 
as contact members having, for example, a curved smooth surface. 
With the rear wheels adapted to be positioned immediately below the pivots 
when the handle body is inclined at an angle appropriate to use, 
variations in the distance between the pivots and the floor surface can be 
minimized even if the angle of inclination alters to some extent owing to 
differences in the height of the users or to the movement of the hand 
holding the handle. This serves to maintain the suction opening portion in 
close proximity to or in contact with the floor surface as desired. 
According to the invention described above, the suction opening portion can 
be brought into or out of contact with the floor surface by the turn of 
the handle without using any complex mechanism but with an extremely 
simple construction. The cleaner of this invention is therefore available 
at a reduced cost with a stable quality and is commercially very useful.