Fluent material handling – with receiver or receiver coacting mea – With manipulation of flexible or collapsible receiver or supply
Reexamination Certificate
2002-03-13
2003-06-10
Douglas, Steven O. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
With manipulation of flexible or collapsible receiver or supply
C141S179000, C141S270000, C141S279000, C141S284000, C053S385100
Reexamination Certificate
active
06575207
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an opening apparatus for bags in which a nozzle is moved into mouths of respective bags that are continuously conveyed and a gas is jet into the bags from a discharge opening of the nozzle.
2. Prior Art
Continuous conveying type bag-filling packaging machines perform a series of packaging operations while self-standing bags are continuously conveyed. Such operations includes opening of the bag mouths, spreading of the bag bottoms by blowing a compressed gas into bags, filling of the bags with contents and sealing of the bag mouths.
Typical continuous conveying type bag-filling packaging machines include either one of two types of bag mouth opening apparatuses: a following-reciprocating motion type apparatus and a rotary loop type apparatus.
In the following-reciprocating motion type, a nozzle that blows a gas into the bags repeats a following motion and a return motion in the conveying direction of the bags. During the following motion, the nozzle is advanced toward the mouth of the corresponding bag and is inserted into mouth. Then, a gas is blown into the bag from the discharge opening of the nozzle, so that the bag bottom is spread open. The nozzle is next retreats and is separated from the bag mouth. However, this type has several problems.
First, a certain distance is required for the acceleration of the nozzle from a stopped state to a bag conveying speed, and a certain deceleration distance is also required in order to stop the nozzle after the nozzle is separated from the bag mouth. As a result, the distance required for the reciprocating motion of the nozzle tends to be correspondingly long, so that overall size of the packaging machine increases, requiring a large installation space.
Second, time is likewise required for acceleration and deceleration, and this hinders increase in the running speed of the packaging machine.
Third, since the reciprocating motion and advancing and retracting action of the nozzle are repeated, vibration and noise are considerable, deteriorating the working environment. This problem becomes more conspicuous as the packaging machine is operated at higher speeds.
Fourth, in cases where a plurality of sets of nozzles are installed and a plurality of bags are opened at one time, the inertia becomes large, thus requiring an additional distance and time for acceleration and deceleration, leading to an increase in the size of the apparatus, and making it difficult to achieve a desired speed increase.
In the rotary loop type, on the other hand, numerous nozzles are installed at equal intervals on a chain that is mounted on a pair of sprockets, and these nozzles are caused to revolve at the same speed as the conveying speed of the bags. A part of the revolving path of these nozzles is set to run along the conveying path of the bags; and in this area of revolving path of the nozzles, the nozzles are advanced toward the bag mouths and inserted thereinto. Then, a gas is jet into the bags from the discharge openings of the nozzles so as to spread the bottoms of the bags, after which the nozzles are retracted and separated from the bag mouths.
In this rotary type, however, the structure that causes the nozzles to revolve and to advance and retract is complicated. Furthermore, since the nozzles revolve in the horizontal plane, the connecting structure of the nozzles with a compressed gas source, etc. is also complicated, and the maintenance and cleaning characteristics are poor, thus being costly. In addition, since the structure is large in size, a large installation space is required for the packaging machine as whole. Moreover, the vibration and noise derived from the advancing and retracting action of the nozzles are present as in the above-described following-reciprocating motion type apparatus.
SUMMARY OF THE INVENTION
The present invention is to solve the problems with the prior art bag opening apparatuses used in continuous conveying type bag-filling packaging machines.
It is, therefore, an object of the present invention to provide an apparatus for opening bags that is simple in structure and compact in size, produces little vibration and noise and increases the speed of operation.
The above object is accomplished by a unique structure for an opening apparatus for bags in which a nozzle is inserted into a mouth of a bag among bags that are continuously conveyed at a constant speed and uniform intervals, and a gas is caused to jet into the bag from a discharge opening of the nozzle so as to open the bag, and in the present invention,
the nozzle is continuously revolved on a circular track with the discharge opening thereof being kept to face the bottom of the bag so that the discharge opening advances toward and withdraws from the mouth of the bag which is on a conveying path of the bags, the circular track being substantially parallel to a conveying direction of the bags and within a plane that runs along longitudinal direction of the bags, and
a time required for the nozzle to complete one revolution is set at an integral multiple of a time required for one bag to be conveyed over a distance between bags.
Needless to say, it is preferable that the speed of the nozzle in the conveying direction of the bags (i.e., the velocity component in the conveying direction) be set so that this speed is substantially the same as the conveying speed of the bags while the nozzle is inserted in the mouth of the corresponding bag. This can be realized in an ideal form by, for instance, setting the speed of the nozzle on the circular track at a speed that is constant and that is substantially the same as the conveying speed of the bags. The direction of revolution of the nozzle must be a direction that is the same as the conveying direction of the bags.
In the above structure, the nozzle is attached to a rotation transmitting member that performs a translational motion with the same radius of revolution and in the same direction of revolution as the nozzle.
The rotation transmitting member that performs this translational motion consistently faces in the same direction. Accordingly, the discharge opening of the nozzle also consistently faces in the same direction (toward the bottom of the corresponding bag) during the revolution of the nozzle. Of course, the revolution of the nozzle is also a translational motion. The mechanism that causes the rotation transmitting member to perform the translational motion includes two rotating shafts and supporting shafts. The rotating shafts rotate in synchronization in the same direction and respective supporting shafts that are attached to the rotating shafts. The supporting shafts are provided so as to be in eccentric positions which are offset by equal distances in the same direction with respect to the rotating shafts and revolve about the rotating shafts by the rotation of the rotating shafts. The rotation transmitting member is connected to these supporting shafts and makes a translational motion.
It is also preferable to install a plurality of nozzles on the rotation transmitting member so that the nozzles are arranged in the same direction as the conveying direction of the bags at intervals that are the same as the distance between bags that are next to each other. When only a single nozzle is installed along the conveying path of the bags, the time required for the nozzle to complete one revolution is set to be equal to the time that is required for one bag to be conveyed over the distance between bags. To the contrary, when a plurality of nozzles are employed, the time required for each nozzle to complete one revolution is set at a time that is obtained by multiplying the time required for one bag to be conveyed over the distance between bags next to each other by the number of nozzles. In this case, the radius of revolution of the nozzles is increased by the same factor.
The opening apparatus of the present invention is used mainly for bags that are conveyed horizontally in the direction of width of the bags with the bags bein
Ikemoto Iwao
Koga Shoichi
Douglas Steven O.
Koda & Androlia
Toyo Jidoki Co., Ltd.
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