Sewing – Elements – Cooling
Reexamination Certificate
2000-05-05
2001-07-17
Izaguirre, Ismael (Department: 3765)
Sewing
Elements
Cooling
C112S282000
Reexamination Certificate
active
06260494
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sewing machine with a dust removing device. More particularly, the invention relates to a sewing machine with a dust removing device which is so constructed as to prevent trouble such as faulty sewing to be caused when dust including waste thread and waste cloth is collected under a throat plate, in performing, for example, interlock stitch sewing by an overlock sewing machine.
2. Description of the Prior Art
In the event that dust including waste thread and waste cloth to be produced-during sewing operation by a sewing machine, is collected at the underside of a throat plate at which sewing parts such as a looper, fabric feed mechanism and knife driving mechanism are disposed, there is a tendency that a needle thread loop is not formed in a predetermined manner, resulting in a faulty sewing such as skip-stitch. If dust is more collected there, the dust will interfere with movable parts such as a needle and looper, and thus cause the deformation and damage on the movable parts.
In order to prevent the faulty sewing and deformation of the movable parts because of the collected dust as described, the following conventional manner has generally been taken. That is, an air gun is manually operated to spray airflow around the underside of the throat plate, thereby to scatter and remove the collected dust. With this manner, however, it is sometimes required to spray airflow by interrupting the operation of the sewing machine in the course of sewing. That is, not only such a time-consuming and tedious cleaning operation but also a lot of time for this cleaning is required, resulting in a low sewing efficiency. In addition, when airflow is sprayed, the collected dust may scatter and suspend around the sewing machine, thus deteriorating working environment.
To solve these problems, U.S. Pat. No. 5,454,338 discloses a sewing machine equipped with a dust removing device (hereinafter referred to as prior art. This prior art is provided with a fan by which an external air is forced to pass through the radiator of an oil cooler for cooling lubricating oil used for lubricating the interior of the sewing machine. By introducing the airflow caused by the fan and then passed through the radiator, into the inside of the sewing machine, the interior of the sewing machine is retained at positive pressure so as to prevent dust including Waste thread, etc. from entering the sewing machine.
In this prior art so constructed, the function of preventing dust entering the sewing machine can be attained by utilizing the airflow generated by the fan for the oil cooler that is originally equipped with the sewing machine in order to cool lubricating oil. Therefore, as compared to the above-mentioned manual removing means of spraying airflow by the air gun, there is no need to perform such cleaning that is tedious and lowers sewing efficiency. That is, such a self-cleaning operation enables to prevent trouble such as faulty sewing due to the dust collected beneath the throat plate.
However, this prior art is constructed so as to merely prevent dust entering the sewing machine by introducing the above-mentioned airflow to retain its inside at positive pressure. It is therefore impossible to prevent trouble caused by the dust collected beneath the throat plate. Further, the interior of the sewing machine is not a completely closed room, and it is thus unavoidable to make working environment not hygienic. This is because, for example, the introduced airflow is blown out to the exterior from the clearance in a needle location of the throat plate, and dust is scattered and suspended around the throat plate. Furthermore, one which is introduced into the sewing machine is airflow heated by heat exchange with the radiator, and it is suppressed that the heated airflow is blown out to the exterior. Therefore, the temperature in the sewing machine will be gradually increased, thereby to facilitate a temperature rise in the movable parts such as the needle and looper which are likely to be heated by the friction during sewing operation. As a result, the thread in contact with the needle and looper is unexpectively cut by heat.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a sewing machine with a dust removing device which can prevent trouble such as faulty sewing due to the collected dust, and which can also prevent dust from widely scattering and suspending around the upside of a throat plate, to maintain hygienic working environment, by self-cleaning action obtained by effectively utilizing the airflow from a cooling fan disposed originally for cooling lubricating oil.
According to the present invention, a sewing machine having a frame, throat plate, needle location formed on the upper surface of the throat plate, and sewing parts beneath the throat plate, which are all disposed beneath the side of the frame, and having a lubricating oil storage part beneath the frame, is characterized in having a dust removing device which comprises: a cooling fan for feeding a cooling airflow toward an air introducing path for oil cooling formed beneath the lubricated oil storage part, the cooling fan being disposed opposite to the side on which the needle location of the frame is present; an upward air introducing path through which dust is blown up by blowing off a cooling airflow after being fed from the cooling fan and passing through the air introducing path for oil cooling dust, from the underside of the frame to the needle location; and an opening of one end of a suction pipe for collecting dust that is attached to the frame and contains in its interior a forced suction airflow, the opening being disposed sidewise above the throat plate.
With this construction, the cooling airflow generated by the cooling fan that is actuated during sewing operation, is fed to the air introducing path for oil cooling underneath the lubricating oil storage part, so as to cool the lubricating oil stored therein. Thereafter, this cooling airflow is introduced to the upward air introducing path, and blown off from the underside of the frame to the needle location, such that the dust including such as waste thread collected beneath the throat plate, is blown up above the throat plate.
By virtue of such a self-cleaning action, it is able to prevent a faulty sewing due to the dust collected beneath the throat plate, and trouble such as the deformation and damage on the movable parts, such as a needle and looper, due to the interference between the movable parts and the collected dust.
Further, thanks to the dust discharging action by which the airflow containing dust blown up above the throat plate is sucked into the suction pipe for collecting dust, and then fed through the suction pipe to a predetermined place for discharge, it is avoided that the dust blown up from the underside of the throat plate will scatter widely around the upside of the throat plate, thus maintaining working environment clean and hygienic.
Furthermore, the cooling airflow of which temperature is increased by heat exchange with the lubricating oil is not allowed to remain underneath the throat plate but is forced to flow by a forced suction airflow. Thereby, heat does not stay underneath the throat plate. It is therefore able to prevent such trouble that the thread in contact with the needle and looper is unexpectively cut by heat, because of the temperature rise in the movable parts.
Preferably, the air introducing path for oil cooling is provided with a damper for adjusting the amount of blow-off of the cooling airflow fed to the air introducing path, toward the upward air introducing path.
With this construction, according to the kind of the fabric and the kind of the sewing, the blow-off amount of airflow can be arbitrarily adjusted to suppress the blow-up of dust and the occurrence of noise, thus permitting further improvement in working environment.
These and other objects, features, aspects and advantages of the present invention will becom
Inoue Tadanori
Shimizu Yoshihide
Hochberg D. Peter
Holt William H.
Izaguirre Ismael
Vieyra Katherine R.
Yamato Sewing Machine Seizo Co., Ltd.
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