Elastic membrane doors for industrial washer-extractor cylinders

An improved door for a horizontal axis fabric treatment machine. The door is designed to removably cover an access opening in a perforated inner drum and includes a series of interwoven elongated fabric strips which are attached at each end to the drum by a series of buckles. The buckles include a frame portion attached to the drum and a tongue portion attached to an end of the elongated fabric strip. The fabric strips define living hinges adjacent each end thereof, allowing the door to open in a number of directions. The access opening is revealed by opening the buckles on three sides of the door, and pivoting the door about the living hinge provided on the fourth side. The buckles allow the door to be completely removed and replaced without tools. The door exploits membrane stiffness to retain, support, and transfer the weight or load from the door to the surrounding drum.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention generally pertains to industrial fabric treatment 
machines and, more particularly, to access doors for industrial 
horizontal-axis fabric treatment machines. 
2. Description of the Related Art 
During the development of horizontal axis fabric treatment machines it has 
been common to provide a door in the cylindrical sidewall of a clothes 
treatment cylinder or drum to allow access into the interior of the drum 
for insertion of items therein and removal of items therefrom. 
Typically, the door is formed by one or more curved plates of steel. The 
weight of the door combined with the weight of treated fabric thereon 
requires a rather massive support structure to maintain the door on the 
drum. The load on the door is primarily supported by the bending stiffness 
of the door. Bending stiffness describes a resistance to a combination of 
stresses that the door experiences, such as tensile, compressive, and 
shear stresses. Bending stiffness inefficiently supports the weight, and 
requires the door to be mechanically stronger than would be required if 
the membrane stiffness of the door could be exploited. Generally speaking, 
membrane stiffness is a resistance to a single type of stress, such as 
tensile stress, wherein all parts of the door are under tension and 
thereby cooperate to transfer the load to the surrounding drum. 
Doors conventionally employed in fabric treatment machines are stiff and 
inflexible, and require mechanically strong hinges to mount the door to 
the drum. These hinges are expensive, and require the door to pivotally 
open about a fixed axis which, depending upon the orientation of the 
washing machine to the surrounding equipment, may not be convenient. 
Therefore, there exists a need in the art for an access door for an inner 
drum of a fabric treatment machine which selectively pivots about one or 
more axes. Moreover, there exists a need in the art for a door which 
employs or exploits membrane stiffness to support the load of processed or 
treated fabrics, and thereby more efficiently supports the treated fabrics 
than doors which rely upon bending stiffness, as in the prior art. There 
also exists a need in the art for a door which eliminates the need for 
expensive hinges. 
SUMMARY OF THE INVENTION 
The present invention provides a flexible door which covers an access 
opening in a sidewall of a perforated cylindrical drum. The flexible door 
is adapted to removably cover the access opening and provides a flexible 
body section and means for securing the body section to the drum. 
In accordance with the present invention, the body section of the door 
provides a living hinge and is defined by a series of interwoven elongated 
members. Each of the elongated members is formed from an flexible or 
elastic membrane or fabric, and are interwoven to create a strong but 
lightweight flexible body section. The elongated members are interwoven in 
a plain weave, and have at least one end secured to the drum by the 
securing means. The body section is adapted to bend about either end of 
the elongated members to allow the door to open in more than one direction 
and thereby provide access to the interior of the drum via the access 
opening. 
In further accordance with the present invention, the securing means 
comprises a buckle associated with at least one end of the elongated 
members. The buckle, which is preferably of the seat belt-type, has a 
tongue and a frame. One of the tongue and frame is attached to an end of 
the elongated member and the other of the tongue and frame is attached to 
the drum adjacent the access opening. 
In further accordance with the present invention the securing means is 
attached to each end of the elongated members. Since the elongated members 
extend parallel and perpendicular to each other, the flexible door is 
adapted to open in any one of four directions depending upon which 
securing means are unattached from the drum. Also, the door can be easily 
removed from and re-attached to the drum without the use of any tools by 
operation of the securing means. 
Weight bearing upon any of the elongated members is transferred, at least 
in part, to other elongated members. The elongated members are in tension 
and transfer the load efficiently to the surrounding drum. The resulting 
door structure is more light weight, stronger, and easier to open and 
close than the doors known in the art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference to FIG. 1, a horizontal axis, side loading, industrial 
fabric treatment machine 10 is illustrated. The machine 10 includes an 
outer imperforate drum or basket 12 and an inner perforate drum 14 (FIGS. 
2 and 3). As is generally well known in the art, the inner drum 14 is 
supported at each end for rotation within the outer drum 12, and is 
perforated to allow wash liquid to flow therethrough. The outer drum 12 is 
stationary and water impervious, and defines a fluid receptacle in which 
the inner drum 14 rotates. The outer drum includes means (not shown) to 
allow fluid to be introduced therein and removed therefrom. A control 
panel 16 is preferably provided to allow an operator to control and 
monitor the operation of the machine 10. 
As shown best in FIG. 1, the outer drum 12 includes a pair of doors 18 
through which access to the inner drum 14 is available. Naturally, the use 
of two doors 18 is merely illustrative, and can be replaced by a single 
door, or more than two doors, as required. The inner drum 14 provides a 
like number of access doors 20 (FIGS. 2-4), in this case two, which 
automatically align with the doors 18 in the outer drum 12 when the inner 
drum 14 comes to rest at the completion of a cycle. Since the alignment 
means do not make up part of the present invention, and several alignment 
means are known in the art, they will not be further described herein. 
The inner drum 14 is generally cylindrical and may be divided into two or 
more internal compartments. In the inner drum 14 illustrated in FIGS. 2 
and 3, the drum 14 is separated into two compartments, each of which is 
accessible through an access opening 15 which is covered by one of the 
inner access doors 20. 
Each of the inner doors 20 comprise a series of elongated members 22. The 
elongated members 22 are preferably made of a flexible resilient or 
elastic fabric and, most preferably, are woven natural or artificial 
fibers or metal belts. The elongated members 22 are themselves interwoven, 
preferably in a plain weave, as illustrated. 
Ends 24 of the elongated members 22 are attached to the inner drum 14 by a 
securing means which, in the illustrated and preferred embodiment, 
includes a series of seat-belt type buckles 26. As shown best in FIG. 3, a 
tongue 28 of each buckle 26 is attached to an end 24 of each elongated 
member 22, and a frame 30 of the buckle 28 is attached to the inner drum 
14 adjacent the access opening therein. Naturally, this arrangement could 
be reversed so that the buckle tongues 28 are attached to the drum 14 and 
the buckle frames 30 are secured to the ends 24 of the elongated members 
22. 
The elongated members 22 are unattached from the inner drum 14 by 
depressing a button (not shown) on the buckle frame 30, and withdrawing 
the tongue 28 from a slot (not shown) in the buckle 26. Similarly, the 
elongated member 22 is reattached to the inner drum 14 by sliding the 
tongue 28 into the slot in the frame 30 until a projection of the button 
is received within an opening in the tongue 28. 
As is shown in FIG. 3, the access opening 15 is revealed and accessible by 
unlatching the buckles 26 on three of the four sides of the door 20, and 
folding the door 20 away from the inner drum 14. The elongated members 2 
comprising the elastic door 20 are flexible and resilient, and thereby 
allow the ends 24 to define a living hinge adjacent the union with the 
inner drum 14 about which the door 20 pivots or bends. In this manner, the 
elastic or resilient door 20 is able to bend or open in any of four 
directions. The door 20 can be completely removed from the inner drum 14 
simply by unattaching the buckles 26 on all four sides thereof from the 
inner drum 14. 
The buckles 26 illustrated herein attach and un-attach individual ends 24 
of the elongated members 22 to the inner drum 20. It is contemplated that 
the attachment and unattachment of the elongated members 22 and the inner 
drum 14 could be eased and speeded by ganging the buckles 26 along each 
side together so that they are simultaneously operated. Moreover, it is 
contemplated that a single direction of opening may be decided upon and, 
therefore, it may be desirable to gang the buckles 26 along three sides 
together to further speed and ease and speed attachment and unattachment 
of the elastic access door 20 and the inner drum 14. 
When the access doors 20 are closed during a wash or water extraction mode 
of machine operation, a considerable weight of material being treated 
bears against the access doors 20. Since the access door 20 connects or 
attaches to the inner drum 14 at several points along each edge and due to 
the elastic properties of the interwoven elongated members 22, the weight 
or load of the treated material is transferred to the drum 14 at numerous 
spaced-apart locations surrounding the access opening. When the weight is 
placed upon one of the elongated members 22, that weight is transferred, 
in part, to the other elongated members 22, due to the weave, placing the 
entire door in tension and efficiently transferring the treated fabric 
load to the drum. The elasticity of the elongated members 22 also allows 
the access door 20 to bulge or deform outwardly. The ability of the door 
20 to deform radially outwardly is limited by the inherent elasticity of 
the elongated members 22 and, at an outer extreme, by the outer drum 12. 
Therefore, the elongated members 22 preferably deform radially outwardly, 
but not so much that the door 20 engages the outer drum 12. 
As used herein the term "fabric" is intended to include resilient or 
compliant natural or artificial fibers such as KEVLAR, polyester, or NOMEX 
which, alone or in combination with other natural or artificial fibers, 
plastics, metals, or alloys are grouped, twisted, matted, woven, or 
otherwise joined to form a continuous or discontinuous sheet, strip, or 
belt of material. For example, instead of a series of interwoven strips of 
material, the doors 20 could be formed of a single continuous perforated 
sheet of resilient or elastic fabric which is attached to the drum 14 over 
the access opening 15 by securing means without departing from the scope 
of the present invention. 
The term "living hinge" as used herein defines a hinge which is integrally 
formed in a material, and is a result of the elastic or resilient 
properties of that material. The term "living hinge" is to be accorded its 
broadest possible interpretation, and is not intended to imply that there 
is a specific axis about which the door bends, or that there is an 
inherent weakness in the material along the axis or at the hinge line. 
Rather, in the present invention, the "living hinge" is integrally 
provided at any point along the straps and, preferably, adjacent each end 
of the straps, depending upon which direction the door is opened. 
While the preferred embodiment of the present invention is shown and 
described herein, it is to be understood that the same is not so limited 
but shall cover and include any and all modifications thereof which fall 
within the purview of the invention.