U.S. patent number 3,696,521 [Application Number 05/101,308] was granted by the patent office on 1972-10-10 for laundry dryer.
This patent grant is currently assigned to Philco-Ford Corporation. Invention is credited to James R. Hubbard.
United States Patent |
3,696,521 |
Hubbard |
October 10, 1972 |
LAUNDRY DRYER
Abstract
A dual-zone clothes dryer in which a smaller drum is disposable
within the main rotatable drum, with the smaller drum in such
driven engagement with the main drum that it is rotated at a speed
higher than that of the main drum, and suitable to achieve tumbling
of clothes within the smaller drum.
Inventors: |
Hubbard; James R. (Moorestown,
NJ) |
Assignee: |
Philco-Ford Corporation
(Philadelphia, PA)
|
Family
ID: |
22283964 |
Appl.
No.: |
05/101,308 |
Filed: |
December 24, 1970 |
Current U.S.
Class: |
34/128; 34/602;
366/234 |
Current CPC
Class: |
D06F
58/04 (20130101) |
Current International
Class: |
D06F
58/04 (20060101); F26b 011/02 () |
Field of
Search: |
;34/128 ;68/4
;259/57 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Dority, Jr.; Carroll B.
Claims
I claim:
1. In apparatus for drying fabrics: a first open-end receptacle;
means supporting said receptacle for rotation about a generally
horizontal axis; door structure movable between a closed position
in which it confronts the open end of said receptacle and an open
position in which access may be had to said receptacle; a second
receptacle smaller than said first receptacle; means removably and
rotatably supporting said second receptacle upon said door
structure in a position such that closing of said door structure
causes said second receptacle to be moved into said first
receptacle and to occupy a position therein in which it may be
rotated about a generally horizontal axis; means for driving said
first receptacle at a speed suitable to cause tumbling of fabrics
contained therein; and means for establishing a driving connection
between said receptacles when said second receptacle is positioned
within said first receptacle, the driving connection being such
that said first receptacle drives said second receptacle at a speed
higher than that of said first receptacle and suitable to cause
tumbling of fabrics contained in said smaller second
receptacle.
2. Apparatus in accordance with claim 1, in which said receptacles
are perforated and there is included means for passing drying air
into said first receptacle and for thereafter passing said air into
and through said second receptacle.
3. Apparatus in accordance with claim 1, and further characterized
in that said door structure is provided with journal means for
rotatably and removably supporting said second receptacle.
4. A clothes dryer comprising: a cabinet; an open-end drum
rotatably supported by said cabinet, said cabinet having an opening
in registry with the open end of said drum; a door normally closing
said opening in said cabinet and movable to a position in which
access may be had to the interior of said drum; and a second
smaller drum carried by said door and normally disposed within the
larger drum; the construction and arrangement being such that
clothes contained within each of said drums are subjected to drying
air circulating through the cabinet, and provision is made to
rotate said drums simultaneously each at a speed suitable to
produce tumbling of clothes therein.
5. In a dual-zone laundry dryer: a main drum rotatable about a
substantially horizontal axis; means for driving said main drum at
a speed suitable to tumble fabrics therein; a smaller drum disposed
within the main drum and rotatable about a substantially horizontal
axis eccentric with respect to the axis about which said main drum
is rotatable; and means establishing a driving connection between
said main drum and said smaller drum, said driving connection being
such that said smaller drum is driven by said main drum at a speed
higher than that of said main drum and suitable to tumble fabrics
in said smaller drum.
6. Apparatus in accordance with claim 5, and further characterized
in that said driving connection comprises: an internal gear carried
by and concentric with the axis of rotation of said main drum; and
an external gear carried by and concentric with the axis of
rotation of said smaller drum and in driven engagement with said
internal gear.
7. Apparatus in accordance with claim 6, and in which said main
drum has a forward access opening, said internal gear surrounds
said opening, and said external gear surrounds and is carried by
the peripheral wall of said smaller drum.
Description
BACKGROUND OF THE INVENTION
This invention is concerned with household laundry apparatus and
especially with improvements in laundry dryers of the kind having a
clothes-containing drum rotatable about a horizontal axis. In the
use of dryers of this kind a clothes load may contain a variety of
fabrics which require different conditions for optimum drying. For
example different drying times and temperatures are desirable for
fabrics of different types, and a degree of tumble agitation which
is optimum for one type of fabric may not be the best for others.
Frequently this is the case with more delicate fabrics. The result
has been impairment of drying efficiency, particularly if a small
load of delicate fabrics is to be dried in a large drum.
SUMMARY OF THE INVENTION
It is my objective to provide a dual-zone clothes dryer which is
not subject to the mentioned deficiencies. Broadly, this objective
is achieved by utilizing the available capacity of the machine in
such a way as to facilitate simultaneous drying of different types
of clothing in separate drying zones. In achievement of this
objective I utilize a drying basket or drum of smaller size, which
may be contained within the larger drum, and provide for subjecting
clothes loads within each drum to the drying action of air
circulating within the machine. Since the air is introduced first
into the larger drum and thereafter flows through the smaller drum,
the air in the smaller drum is cooler, ensuring more gentle drying
action therein. Optimum drying time for special fabrics is readily
achievable, since the smaller drum may be removed from the machine
at any time in the cycle.
It is also an object of the invention to provide a dual-zone drying
machine operable by a single, very simple, motor drive.
The apparatus of the invention is featured by the ease with which
the smaller drum may be loaded and installed within the larger and
by the fact that provision of the two drums requires no major
changes in drive means, controls or heating circuits.
In summary, this invention provides a dryer construction having a
small drum within which delicate fabrics may be dried, and which
drum may readily be associated with or detached from the machine to
meet various drying requirements. In the preferred embodiment, the
invention is featured by the fact that, while each drum is driven
at a speed suitable to promote tumbling of the clothes therein, the
smaller drum derives its movement wholly from the larger drum.
BRIEF DESCRIPTION OF THE DRAWING
In the accompanying drawings:
FIG. 1 is a perspective illustration of a horizontal-axis laundry
dryer embodying the invention;
FIG. 2 is a side sectional-elevational view showing portions of the
dryer of FIG. 1 on a larger scale;
FIG. 3 is a perspective illustration of the smaller drying drum
shown disassociated from the drying machine;
FIG. 4 is an exploded view illustrating features of construction of
the smaller drum and showing the manner in which it may be
removably associated with the door of the dryer cabinet; and
FIG. 5 is a front elevational view of the two drums used in the
machine, showing the drums disassociated from the dryer and
illustrating the preferred manner of driving the smaller drum.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Making initial reference to FIGS. 1 and 2, the illustrated laundry
dryer 10 comprises a generally rectangular cabinet 11 provided with
a first, larger, open-end receptacle or drum 12 which is mounted
within the cabinet through the agency of suitable bearing means
13-14 (FIG. 2). The open end of this drum confronts an aperture 15
provided in the forward portion of the cabinet, as is seen in FIG.
1. Suitable door structure, for example the swinging door shown at
16, is mounted on the cabinet for movements between a closed
position (FIG. 2), in which it confronts the open end of the drum
12, and an open position in which access may be had to said drum.
It will be understood that a suitable latch (not shown) would be
provided to hold the door 16 in closed position.
Preferably the drum 12 is of cylindrical shape and its periphery is
formed of imperforate sheet steel. Baffles 17 provide for tumbling
of the clothes within the drum 12. Resistive heater means, shown
diagrammatically at 18 in FIG. 2, is provided to heat the air which
dries the clothes and it will be understood that the apparatus
would further include motor means (not shown) for rotating the
drum, for example, through the agency of a belt 19 which surrounds
the drum. Air propelling means, shown diagrammatically as a fan
identified at F, is provided for moving the air upwardly past the
heater 18, thence through the perforated rear wall 20 of the drum
and into contact with clothes contained therein. As thus far
described the main drum and drive apparatus is conventional.
As shown by arrows designating air flow in FIG. 2, the circulating
air flows toward the forward part of the drum 12 and, when the
smaller drum to which detailed reference will be made hereinafter
is not in place, exits directly through the open end of drum 12 and
through perforations provided in the rear wall 21 of cabinet door
16. As shown by the arrows, the air completes its circulatory flow
by passing downwardly through lint collecting means shown at 22 and
thence to a suitable exit (not shown).
In particular accordance with this invention, the dryer is provided
with a second receptacle or drum 23, smaller than the first drum.
This second drum, which may conveniently be fabricated of molded
plastic material to minimize the weight thereof, is provided with a
fixed end wall 24 which is perforated, and with a removable
perforated cap or wall 25 which is flanged, as shown at 26, (see
particularly FIG. 4) releasably to retain the cap on the drum. The
removable cap 25 provides access to drum 23, in the manner shown in
FIG. 4, and serves also to retain a lint filter 27. This filter is
supported between the removable cap wall 25 and a flanged portion
28 of smaller drum 23. The smaller drum is provided with baffles 29
which may be conventional in nature.
Drum 23 is removably and rotatably supported upon the door 16 and,
for this purpose, the end wall 24 of drum 23 is provided with an
externally splined shaft 30 which is receivable within an
internally splined hollow shaft or socket structure 31 mounted in
the door 16 through the agency of a journal 32 and a set of
bearings 33. The end wall 24 of the smaller drum is provided with a
flange 24a which seats against the front of the cabinet, as shown
at 24b in FIG. 1, to prevent inadvertent dislodgement of the drum
23 when it is in use. To provide for driving the smaller drum at a
desired speed, different than that of the larger drum, the journal
32 is so located and secured within the door that the socket
structure 31 defines a rotational axis A for the smaller drum which
is eccentric with respect to the axis B of the larger drum (FIG.
2).
As will now be understood, smaller drum 23 may readily be
associated with and disassociated from the door and access may be
had to its interior through the cap structure 25, 26. If desired,
means (not shown) may be provided to cover the internally splined
socket structure 31 when the smaller drum is not in use.
When the smaller drum is in use, circulating air flows first
through the larger drum and thereafter through the smaller drum,
exiting through perforated drum wall 24 into and through the door,
as shown by the arrows in FIG. 2. As noted above it is of
advantage, in drying certain fabrics, that the air is at a lower
temperature by the time it reaches the smaller drum.
Preferably the wall 21 of the door is also perforated, as shown at
21a in FIG. 1, in a lower region which is not covered by the
smaller drum when the latter is in place. This permits some outflow
of air directly from the larger drum, even if the smaller drum is
in use.
While the invention is not limited to use of drums of any
particular size, the larger drum 12 may, for example, have a
diameter of about 29 inches and its forward access opening 15a may
have a diameter of about 18 inches. As shown below, when a larger
drum having these dimensions is used, the smaller drum 23 will have
a diameter of about 12 inches. A drum of this size is readily
insertable within the larger drum when the door 16 is swung from
the position shown in FIG. 1 to the position shown in FIG. 2.
As will be understood, the larger drum is driven through the belt
19 and drive motor (not shown) at a speed suitable to cause
tumbling of fabrics contained therein, for example about 48 rpm,
for a 29 inch drum. This speed, and use of appropriate baffles,
provides a satisfactory tumble pattern.
In the broader aspect of the invention, any convenient means may be
employed for driving the smaller drum at the proper tumble speeds.
However, it is a feature of the preferred embodiment of my
invention that a drive connection between the drums is established
automatically when the second drum is positioned within the first,
and it is highly advantageous that the smaller drum be driven by
the larger drum. By use of such an arrangement it is possible to
achieve speeds which are optimum for the achievement of tumbling in
the two drums, without imposing any unusual requirements as to
power or drive mechanism for the larger drum.
Frictional drive means may be interposed between the two drums,
with the resultant advantage of low noise, but I prefer to use an
internal gear secured to the larger drum 12 and extending around
its opening 15a. This gear may comprise an internally toothed belt
of suitable material, for example plastic material. An external
gear is provided -- also preferably as a belt -- and extends about
the periphery of the smaller drum, adjacent the region in which it
is supported by the door.
The gearing arrangement appears to best advantage in FIGS. 1 and 5.
The external belt gear 34 is secured in any suitable fashion, about
the periphery of smaller drum 23, while the internal belt gear 35
extends and is secured -- by any convenient means -- around the
access opening 15a of the larger drum and lies generally in the
plane of said access opening, which is in registry with the opening
in the forward wall of the cabinet. Although the gear teeth
provided on the two belts need not be precisely formed, preferably
they are of approximately involute shape. As the door 16, carrying
the smaller drum, is swung toward the closed position the external
teeth of gear ring 34 are brought into engagement with the internal
teeth of ring 35. The two drums are shown in FIG. 5 disassociated
from the cabinet, and a portion of the forward wall of drum 12,
which wall defines the drum opening 15 a, is shown broken away to
illustrate the engagement between the gears 34 and 35. If necessary
the ends of the teeth may be bevelled to accommodate engagement and
disengagement thereof.
As mentioned above, a drum 29 inches in diameter must be rotated at
about 48 rpm to achieve a value of centrifugal force within the
drum which is slightly less than the force of gravity. As is known
in this art, a value for centrifugal force slightly less than
gravity is required for proper tumbling in a horizontal axis
clothes dryer. In any particular design the smaller drum must be of
a diameter such that it will pass freely into the larger drum.
Further, if it is to carry an external gear or friction means, the
diameter of the smaller drum also must be so chosen that it rotates
at a speed which results in a value of centrifugal force within
said smaller drum which is slightly less than the force of gravity.
As shown below, a smaller drum 12 inches in diameter meets these
conditions.
The speed of rotation of the larger drum, multiplied by the ratio
of the diameters of the two gears, equals the speed of rotation of
the smaller drum. For simplicity in calculating the rotational
speeds of the drums, the value given above for the diameter of the
smaller drum (12 inches) should be understood as comprising the
diameter of the pitch circle of its external gear. Similarly, the
diameter of the opening 15a (18 inches) should be understood as
being the diameter of the pitch circle of the internal gear carried
by the larger drum.
Since, in the particular apparatus under consideration, the larger
drum carries an internal gear which is concentric therewith and is
18 inches in diameter, and since the diameter of the external gear
is approximately equal to that of the smaller drum, the speed of
rotation of the smaller drum is 48 .times. 18/12 = 72 rpm. This can
be shown to yield a value for centrifugal force which is in the
region of 0.9 G, and proper tumbling is achieved.
* * * * *