U.S. patent application number 09/883527 was filed with the patent office on 2002-02-28 for device for controlling the pressure of fabric pressure shoes on sewing machines or the like.
Invention is credited to Guerreschi, Carlo.
Application Number | 20020023577 09/883527 |
Document ID | / |
Family ID | 11461855 |
Filed Date | 2002-02-28 |
United States Patent
Application |
20020023577 |
Kind Code |
A1 |
Guerreschi, Carlo |
February 28, 2002 |
Device for controlling the pressure of fabric pressure shoes on
sewing machines or the like
Abstract
An automatic control device that basically employs a pneumatic
system that controls the pressure exerted on the shaft of the
fabric pressure shoe, pressure that was traditionally exerted by
spring systems or in any case mechanical-type systems that were
always based on the pressure or the pull of a spring. Basically
automatic control device (1), installed above shaft (2) on which
fabric pressure shoe (3) is mounted, consists of cylinder (4) in
the chamber of which piston (5) slides. The chamber of cylinder (4)
is connected at the top to a tube (8) that leads to pneumatic
control system (9). This system includes pressure regulator (10) of
a type suitable for performing precision control of the pressure in
the air circuit.
Inventors: |
Guerreschi, Carlo; (Verona,
IT) |
Correspondence
Address: |
NOTARO & MICHALOS P.C.
EMPIRE STATE BUILDING
350 FIFTH AVENUE, SUITE 6902
NEW YORK
NY
10118
US
|
Family ID: |
11461855 |
Appl. No.: |
09/883527 |
Filed: |
June 18, 2001 |
Current U.S.
Class: |
112/237 |
Current CPC
Class: |
D05B 29/02 20130101;
D05D 2207/02 20130101 |
Class at
Publication: |
112/237 |
International
Class: |
D05B 029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2000 |
IT |
VR2000A000060 |
Claims
1. Device for automatic control of the pressure exerted by the
fabric pressure shoes of preferably industrial-type sewing machines
characterized by the fact that it employs a pneumatic system that
includes at least one cylinder (4) in which piston (5) slides,
piston that is connected, through special connections (6) to shaft
(2) of fabric pressure shoe (3) and by the fact that the inner
chamber of said cylinder (4) is connected, by special tubes (8), to
a pneumatic control system which includes special pressure
regulators (10) equipped with stabilizing valves or the like with
variable settings.
2. Device for automatic control of the pressure exerted by fabric
pressure shoes according to claim 1, characterized by the fact that
said piston (5), which is connected to shaft (2) of the shoe
through arm (6), is provided, along its outer edge, with a
ring-shaped groove designed to house an elastic ring or "O-ring"
seal (7) with a round and floating type cross section.
3. Device for automatic control of the pressure exerted by fabric
pressure shoes according to claim 1, characterized by the fact the
cylinder chamber is connected at the top to a tube (8) which
terminates at a pneumatic control system (9) that includes special
pressure regulator (10) of the type designed to control the
pressure in the air circuit with precision.
4. Device for automatic control of the pressure exerted by fabric
pressure shoes according to claim 1, characterized by the fact that
this control is performed by pressure regulator (10) through a
suitable pressure reducing and stabilizing valve and the delivery
rate of this valve can be modified by pressure regulator (11).
5. Device for automatic control of the pressure exerted by fabric
pressure shoes according to claim 1, characterized by the fact that
auxiliary compensation device (12) is inserted between said
cylinder (4) and said pressure regulator (10) and compensates for
small variations in pressure before causing the pressure regulator
valve to operate.
6. Device for automatic control of the pressure exerted by fabric
pressure shoes according to claim 1, characterized by the fact that
a second outlet (14) can be installed in the lower part of cylinder
(4) to which an auxiliary pneumatic valve can be connected designed
to help lift the shoe when introducing and extracting the
fabric.
7. Device for automatic control of the pressure exerted by fabric
pressure shoes according to claim 1, characterized by the fact that
the connection between said compensation device and said fabric
pressure shoe shaft, performed using arm (6), can also be obtained
in parallel with a suitable mechanical connection or joining
component.
Description
[0001] This industrial invention patent proposes a device for
automatically controlling the pressure of fabric pressure shoes on
preferably industrial-type sewing machines, meaning those equipped
with claw, roller or belt conveying system or other similar
conveying system.
[0002] It is an automatic control device that basically uses a
pneumatic system for controlling the pressure exerted on the shaft
of the fabric pressure shoe, pressure which was traditionally
exerted by spring systems or in any case by mechanical-type systems
that were always based on the pressure or the pull of a spring.
[0003] The automatic control device according to the invention,
compared to known solutions, offers the basic advantage of having
clearly improved thrust conditions on the fabric pressure shoes by
greatly reducing inertia and by constantly maintaining correct
working pressure at any speed and with any thickness of the fabric
being processed.
[0004] As is known sewing machines, in their most common form, are
machines that perform mechanical sewing of two pieces of fabric. In
industrial sectors they are conceived according to different
structural techniques depending on the various operations they are
destined to perform.
[0005] Single or multi-needle machines are known, for example, used
to sew garments such as jeans or casual pants in general, work
clothes, shirts or even others.
[0006] These industrial sewing machines, based on their different
versions, can sew on the widest variety of fabrics, on the yokes,
on the rear or front crotch, on the leg felling or for the widest
variety of applications. They come in special versions for light or
extra-heavy fabrics with increased pressure shoe height and
extended needle bar travel.
[0007] Normally all these versions are equipped with a fabric
pressure shoe that carries a vertical shaft including a mechanical
pressure device designed to absorb shoe shocks. This system is
necessary both to compensate for the thrusts generated by different
sewing speeds and, above all, to perform sewing on different
thicknesses of fabric.
[0008] FIG. 1 illustrates one of-these traditional pressure
devices. This device, as is shown, includes pin A equipped with
head B in which spring C is inserted. Pin A slides in a special
seat machined on shaft D of shoe E whereas the head of the pin
itself is kept under pressure by presser F. The height of this
presser can be adjusted by screwing pawl G.
[0009] It is clear that by tightening pawl G the spring will
generate greater pressure on shoe E.
[0010] This structural technique, used to absorb shock forces on
fabric pressure shoes in most if not all sewing machines, is not
without practical problems. These are principally related to
difficulties in controlling the pressure during work phases: in all
cases, and these are the majority, where the machine encounters
variations in the thickness of the fabric while it is sewing.
[0011] In these cases the spring pressure mechanisms do not adapt
with the necessary precision to the needs of the fabric. This is
because spring contrast mechanisms, as is well known, do not exert
constant pressure during work phases but, on the contrary, generate
an increase in pressure when their operating space is reduced.
[0012] This all has repercussions on the quality of sewing and on
sewing speed. Speeds must sometimes be greatly reduced all to the
detriment of manufacturing times and the cost of the finished
product. The object of the invention is to have conceived and
created a device for automatic control of fabric pressure shoe
pressure that is able to overcome the above-indicated
inconveniences. That is able, in other words, to maintain constant
shoe operating pressure during all sewing phases.
[0013] The fabric pressure shoe control system that has been
conceived and created, in conformity to one of the main goals of
the invention, is able to keep shoe operating pressure constant
during all sewing phases independent from the thickness of the
fabric. This makes the machine able to work on any fabric at high
sewing speeds.
[0014] The invention in question is based, as mentioned previously,
on installation of a control device that uses a totally automatic
pneumatic-type system. This offers the basic advantage of
guaranteeing constant operating pressure following initial
adjustment of the shoe at a certain work pressure.
[0015] The above-described objects and advantages are all achieved,
according to the invention, by a device for automatic control of
the fabric pressure shoe pressure on sewing machines, preferably
industrial sewing machines, characterized by the fact that it
employs a pneumatic system that includes at least one cylinder in
which a piston slides, piston that is connected, through special
connections, to the fabric pressure shoe shaft and by the fact that
the inner chamber of said cylinder is connected, through suitable
tubes, to a pneumatic control system that includes special pressure
regulators equipped with stabilizing valves or the like with
adjustable settings.
[0016] Other particular characteristics of the invention can be
better understood by the following description, given as a
non-exclusive example and given in reference to the attached
drawing where:
[0017] FIG. 1 gives a schematic view of a traditional control
system used to determine the pressure exerted by known fabric
pressure shoes;
[0018] FIG. 2 gives a schematic view of the device as a whole
according to the invention for automatic control of the pressure
exerted by fabric pressure shoes for industrial sewing machines or
the like;
[0019] FIG. 3 gives a detailed schematic view of the pneumatic
control device.
[0020] In reference to these attached figures number 1 indicates
the overall device according to the overall invention for automatic
control of fabric pressure shoe pressure on industrial type sewing
machines, meaning those equipped with claw, roller or belt
conveying systems or any other similar conveying system.
[0021] Automatic control device 1, installed above shaft 2 on which
fabric pressure shoe 3 is mounted, basically consists of cylinder 4
in which piston 5 slides.
[0022] As FIG. 2 shows piston 5, which is connected to shaft 2 of
the shoe through arm 6, mounts, along its external edge, a ring
groove suitable for housing elastic ring or "O-ring" seal 7 with a
round and floating type cross-section.
[0023] Seal 7 is the type suited to exert "floating" sliding by the
piston inside the cylinder chamber: sliding with minimum friction
and without any possibility of sticking to or "gluing" to the
cylinder sleeve.
[0024] The top part of the cylinder chamber is connected to tube 8
which terminates at pneumatic control system 9. A special pressure
regulator 10 belongs to this control system. This regulator is
designed to control the pressure of the air circuit with great
precision. This control is executed and performed by pressure
regulator 10 using a suitable reducing and stabilizing valve. The
delivery rate of this valve can be varied using pressure regulator
11.
[0025] Compensation device 12 can if necessary be inserted between
cylinder 4 and pressure regulator 10. This device compensates for
small variations in pressure before it trips the pressure
regulator's valve.
[0026] In its turn pressure regulator 13 is connected, through tube
13, to a pneumatic circuit that supplies the necessary amount of
pressurized air.
[0027] It is possible, with this control system, to set a certain
operating air pressure in the upper chamber of cylinder 4 and this
will be kept constant in all conditions of thrust exerted by fabric
pressure shoe 3's shaft 2, compensating for any variations in
thrust caused by changes in fabric thickness or other thrusts
caused by sewing speed.
[0028] While small pressure variations can be absorbed by
compensation chamber 12, all substantial variations must be
controlled and stabilized by pressure regulator 10 and by the
reducing and stabilizing valve contained in it.
[0029] Lifting of the shoe when introducing and extracting the
fabric is also done using a pneumatic control system. This performs
suitable changes in the pressure exerted by the pneumatic system in
the upper chamber of the cylinder.
[0030] Naturally the entire system is controlled by a computerized
control system that determines and inputs all the different options
and working parameters.
[0031] A second outlet, 14, is also provided for on the lower part
of the cylinder. This has the advantage of being able to connect to
an auxiliary pneumatic valve designed to help lift the shoe when
introducing and extracting the fabric.
[0032] The automatic control system that has been described can be
seen to clearly improve thrust conditions by fabric pressure shoes
by greatly reducing inertia and maintaining correct working
pressure constant at whatever speed and on whatever thickness of
fabric being processed. The solution that has been described also
illustrates the possibility of using arm 6 as a direct connection
between the compensation device and the fabric pressure shoe shaft.
But this connection can also be done in parallel with a suitable
mechanical connection or joining component.
[0033] A technician in the sector can foresee several modifications
and variants that can be brought to the device described and
illustrated above as a non-exclusive example, offering solutions
that are to be held to be included in the area of protection of the
invention as defined by the following claims.
* * * * *