Continuous wrapping machine and continuous wrapping method of magnetic powder

A compact and efficient continuous wrapping machine capable of measuring out certain amounts of a magnetic powder automatically and wrapping them in wrapping film, the continuous wrapping machine comprising a measuring drum, a sealing drum, and a sealing device. The measuring drum includes a means for retaining measured-out amounts of the magnetic powder on its periphery and a means for cutting off the retaining force of the retaining means to transfer the measured-out amounts of the magnetic powder to the sealing drum. The sealing drum includes a means for retaining the measured-out amounts of the magnetic powder on a first continuous wrapping film fed onto its periphery. The sealing device seals the first continuous wrapping film and a second continuous wrapping film, which is fed onto the measured-out amounts of the magnetic powder on the sealing drum, together around each of the measured-out amounts of the magnetic powder.

BACKGROUND OF THE INVENTION

This invention relates to a continuous wrapping machine and a continuous wrapping method of magnetic powder. More specifically, this invention relates to a wrapping machine and a wrapping method to wrap magnetic powder such as materials of disposable pocket body warmers in wrapping film automatically and continuously.

Disclosed in the Japanese Examined Patent Publication No. 108687/H7 (1995) is a manufacturing machine of a disposable pocket body warmer, which comprises four drums; i.e., a measuring drum, a transfer drum, a conveying drum, and a sealing drum. With the four drums working in conjunction with one another, the machine measures out certain amounts of a material and puts the measured-out amounts of the material between continuous wrapping films, and seals the films together to produce body warmers efficiently.

On the other hand, the inventor of the present invention made a further study and completed a magnetic powder-wrapping technology which enables the construction of a compact continuous wrapping machine capable of producing body warmers efficiently.

SUMMARY OF THE INVENTION

According to the first feature of the present invention, there is provided a continuous wrapping machine for wrapping a magnetic powder in wrapping film, which comprises a measuring drum, a sealing drum, and a sealing device. The measuring drum includes a means for retaining measured-out amounts of the magnetic powder on its periphery and a means for cutting off the retaining force of the retaining means to transfer the measured-out amounts of the magnetic powder to the sealing drum. The sealing drum includes a means for retaining the measured-out amounts of the magnetic powder on a first continuous wrapping film fed onto its periphery. The sealing device seals the first continuous wrapping film and a second continuous wrapping film, which is fed onto the measured-out amounts of the magnetic powder on the sealing drum, together around each of the measured-out amounts of the magnetic powder.

According to the second feature of the present invention, there is provided the continuous wrapping machine of the first feature. The magnetic-powder-retaining means of the measuring drum comprises magnets which are arranged under a plurality of recesses formed in the periphery of the measuring drum. The retaining-force-cutting-off means of the measuring drum comprises a magnetic-screening plate disposed between its inside and magnets.

According to the third feature of the present invention, there is provided the continuous wrapping machine of the first feature. The magnetic-powder-retaining means of the sealing drum comprises magnets which are arranged under a plurality of recesses formed in the periphery of the sealing drum.

According to the fourth feature of the present invention, there is provided the continuous wrapping machine of the first feature. The sealing device comprises a sealing roller with sealing strips on its periphery for sealing the first and second continuous wrapping films together around each of the measured-out amounts of the magnetic powder.

According to the fifth feature of the present invention, there is provided a method of wrapping a magnetic powder in wrapping film continuously. The method comprises the steps of (i) measuring out certain amounts of the magnetic powder and putting the measured-out amounts of the magnetic power between first and second continuous wrapping films, and (ii) sealing the first and second continuous wrapping films together with heat around each of the measured-out amounts of the magnetic powder.

The advantages offered by the first feature of the present invention are as follows. While turning, the measuring drum measures out certain amounts of a magnetic powder, retains them on its periphery with its magnetic-powder-retaining means, and carries them to the zone, where its retaining-force-cutting-off means is disposed, to transfer them onto the first continuous wrapping film being fed onto the periphery of the sealing drum. While the sealing drum is turning, the measured-out amounts of the magnetic powder are retained on the first continuous wrapping film by the magnetic-powder-retaining means of the sealing drum and overlaid with a second continuous wrapping film fed to the sealing drum. Then, the sealing device seals the first and second wrapping films together around each of the measured-out amounts of the magnetic powder. Thus, the measuring, wrapping, and sealing of the magnetic powder are carried out continuously by the rotation of the two drums. Besides, the measuring, wrapping, and sealing are efficient because there is not such energy loss in rotational motion as there is in reciprocating motion. Moreover, the main components of the continuous wrapping machine are the two drums alone; therefore, the continuous wrapping machine is relatively compact.

The advantages offered by the second feature of the present invention are as follows. Measured-out amounts of magnetic powder in recesses of the measuring drum are retained in them by the attraction of magnets inside the measuring drum; accordingly, measured-out amounts of magnetic powder in recesses of the measuring drum are carried toward the sealing drum without falling out of recesses. Besides, the magnetic force of magnets inside the measuring drum is cut off by the magnetic-screening plate of the retaining-force-cutting-off means of the measuring drum at the transfer zone between the measuring drum and the sealing drum; accordingly, measured-out amounts of magnetic powder in recesses of the measuring drum are transferred into recesses of the sealing drum without fail.

The advantage offered by the third feature of the present invention is as follows. Measured-out amounts in recesses of the sealing drum are retained by the attraction of magnets inside the sealing drum; accordingly, measured-out amounts of magnetic powder in recesses of the sealing drum are carried toward the sealing device without falling out of recesses.

The advantages offered by the fourth feature of the present invention are as follows. The sealing roller of the sealing device has sealing strips on its periphery; accordingly, the first and second continuous wrapping films are sealed together around measured-out amounts of magnetic powder without fail. Besides, the sealing is made just by the rotational motion of the sealing device; therefore, the sealing is made continuously and efficiently.

The advantages offered by the fifth feature of the present invention are as follows. Certain amounts of the magnetic powder is measured out, and the measured-out amounts of magnetic powder are put between first and second continuous wrapping films; accordingly, the continuous wrapping of magnetic powder can be accomplished just by sealing the first and second wrapping films around each of the measured-out amounts of magnetic powder.

DETAILED EXPLANATION OF THE INVENTION

Referring to the drawings, a preferred embodiment of continuous wrapping machine of the present invention is now described. The continuous wrapping machine wraps up measured-out amounts of a magnetic powder, which is a material for the production of disposable pocket body warmers, in film continuously.

InFIG. 1, the reference sign “A” is the continuous wrapping machine, which comprises a measuring drum1, a sealing drum4, and a sealing device5. In addition to these components, a second sealing device6and a cooling device7may be provided. The second sealing device6and the cooling device7are not indispensable but add to the reliability of the continuous wrapping machine A.

If a cutter80, which cuts two continuous films carrying measured-out amounts of magnetic powder therebetween into packets, and a packing machine90, which packs a certain number of packets at a time, are provided downstream of the continuous wrapping machine A, pocket body warmers are produced continuously.

FIG. 2shows the main part of the continuous wrapping machine A; i.e., the measuring drum1, the sealing drum4, and the sealing device5.

The measuring drum1is provided with a hopper8, which stores and feeds a magnetic powder “m” to the measuring drum1. The magnetic powder “m” is composed of iron powder, water, vermiculite, activated carbon, salts, and so on.

The measuring drum1measures out certain amounts of magnetic powder “m” and feeds them to the sealing drum4. The measuring drum1is provided with a means for measuring out certain amounts of magnetic powder “m”, a means for retaining the measured-out amounts of magnetic powder “m” on the periphery of the measuring drum1, and a means for cutting off the retaining force of the magnetic-powder-retaining means.

The measuring drum1is now described in detail. InFIGS. 3 and 4, the reference numeral10is a rotating shaft driven by a drive unit such as an electric motor. An innermost cylinder11is fixed to the rotating shaft10. An inner cylinder15and an outer cylinder13are fixed to the innermost cylinder11.

Formed in the periphery of the outer cylinder13is a plurality of recesses14to contain the magnetic powder “m”. Any number of recesses14can be formed in the periphery of the outer cylinder13; however, in this embodiment, the recesses14are formed in four longitudinal, or circumferential, rows and several lateral rows from the viewpoint of productivity. Beside, the recesses14can be of any shape; however, in this embodiment, the recesses14are square to match the shape of an ordinary pocket body warmer. The dimensions of the recess14determine the amounts of magnetic powder “m” for pocket body warmers and the recess14can be of any dimensions.

As shown inFIG. 2, the means for measuring out certain amounts of magnetic powder “m” comprises doctor blades19which extend along the axis of the measuring drum1and are in contact with the periphery of the measuring drum1. The doctor blades19can be in any shapes so long as they, in conjunction with the recesses14, are capable of measuring out certain amounts of magnetic powder “m”.

The means for retaining the measured-out amounts of magnetic powder “m” in the recesses14comprises magnets16, which are arranged on and fixed to the periphery of the inner cylinder15so that each magnet16comes under a recess14. Each magnet16is a set of three permanent magnets16a,16b, and16c. The magnets16are arranged along the rotating direction of the measuring drum1, their magnetic poles disposed under the recesses14. A single permanent magnet may be used as the magnet16. Besides, a single electromagnet may be used as the magnet16.

Accordingly, the measured-out amounts of magnetic powder “m” in the recesses14are retained in them by the attraction of the magnets16while the measuring drum1is turning.

The means for cutting off the retaining force of the magnetic-powder-retaining means comprises a magnetic-screening plate18disposed between the magnets16and the outer cylinder13as shown inFIGS. 3 and 4and ensures the transfer of the measured-out amounts of magnetic powder “m” from the measuring drum1to the sealing drum4. The magnetic-screening plate18has a curved screen18aand two support arms18b. The radius of curvature of the curved screen18ais slightly smaller than that of the inside of the outer cylinder13, and the width of the curved screen18ais smaller than that of the outer cylinder13. The length of the curved screen18aalong the circumferential direction of the outer cylinder13is such that the curved screen18acovers one to two lateral rows of magnets16at a time. The support arms18bare journaled on the rotating shaft10so that the magnetic-screening plate18does not rotate along with the outer cylinder13, but stays in any desirable fixed position. The magnetic-screening plate18is made of steel which cuts off magnetic force effectively; however, it may be of any materials so long as they are capable of cutting off magnetic force.

As shown inFIG. 2, the magnetic-screening plate18is disposed at the transfer zone between the measuring drum1and the sealing drum4so that the magnetic-screening plate18cuts off the magnetic force of one to two lateral rows of magnets16at the transfer zone. Accordingly, the measured-out amounts of magnetic powder “m” on the measuring drum1are attracted and transferred to the sealing drum4by the attraction of magnets46(to be described later) of the sealing drum4.

The sealing drum4, in conjunction with the sealing device5, puts the measured-out amounts of magnetic powder “m” between first and second continuous belt-like wrapping films “p” and “q” and seals the films “p” and “q” together around each measured-out amount of magnetic powder “m” to wrap up the same in the film “p/q”. The sealing drum4will be described in detail below.

InFIG. 5, the reference numeral40is a rotating shaft, which is driven by a drive unit such as an electric motor. A cylindrical drum body43is fixed onto the rotating shaft40.

A plurality of recesses44is formed in the periphery of the drum body43to receive the measured-out amounts of magnetic powder “m” from the recesses14of the measuring drum1. The shape, dimensions, and arrangement of the recesses44are generally the same as those of the recesses14.

The sealing drum4is provided with a means for retaining the measured-out amounts of magnetic powder “m” in the recesses44. The magnetic-powder-retaining means comprises a plurality of permanent magnets46, which are arranged inside the drum body43and supported by a support45so that each magnet46comes under a recess44. Electromagnets may be used instead of the permanent magnets46.

The sealing drum4is of thermal-drum structure to seal the first and second continuous wrapping films “p” and “q” together in conjunction with the sealing device5. Namely, a heat source such as an electric heater is built in the rotating shaft40and the drum body43is filled with a heating medium such as oil. The heat generated by the heat source is conducted through the heating medium to the drum body43to keep the temperature of its periphery high enough for heat-sealing.

As shown inFIG. 2, the first continuous wrapping film “p” is fed from its roll (not shown) onto the periphery of the sealing drum4; accordingly, the measured-out amounts of magnetic powder “m” transferred from the recesses14into the recesses44sit on the film “p” in the recesses44and are retained in the recesses44by the magnets46to be carried to the wrapping and sealing zone between the sealing drum4and the sealing device5.

The sealing device5is in contact with the sealing drum4as shown inFIG. 2and seals the wrapping films “p” and “q” together to wrap up the measured-out amounts of magnetic powder “m” in the film “p/q”.

InFIG. 6, the reference numeral50is the rotating shaft of the sealing device5. A sealing roller51is supported on the rotating shaft50. Formed on the periphery of the sealing roller51are five longitudinal, or circumferential, sealing strips53and a plurality of lateral sealing strips54. A heater cartridge (not shown) is built in the sealing device5.

The longitudinal and lateral sealing strips53and54correspond positionally to the part of the periphery of the sealing drum4around the recesses44.

As shown inFIG. 2, a second continuous wrapping film “q” is fed from its roll (not shown) onto the periphery of the sealing device5. The second continuous wrapping film “q” runs halfway round the sealing device5to come to the wrapping and sealing zone between the sealing drum4and the sealing device5.

Accordingly, while the sealing drum4and the sealing device5are rotating, the first and second continuous wrapping films “p” and “q” are caught and sealed together between the part of the periphery of the sealing drum4around the recesses14and the longitudinal and lateral sealing strips53and54of the sealing device5.

As the rotational-phase synchronization between the sealing drum4and the sealing device5can easily be achieved by using gears and a timing belt, time lag or positional slippage does not occur; therefore, sealing can be made accurately.

The second sealing device6comprises well-known heat-sealing rollers. The sealing drum4and the sealing device5seal the first and second continuous wrapping films “p” and “q” together and the second sealing device6seals them together again to ensure the complete sealing of the films. If the reliability of the first sealing is high enough, the second sealing device6is dispensable.

The cooling device7comprises a pair of cooling rollers and cools the sealed part. Because the solidification of the sealed part is accelerated by cooling the hot sealed part, the next step of cutting the continuous wrapping film “p/q” into packets can be hastened.

Referring toFIGS. 1 and 2, the workings of the continuous wrapping machine A will be described below.(1) As the measuring drum1turns, magnetic powder “μm” in the hopper8is attracted into recesses14, which have come in front of the hopper8, by the attraction of the magnets16under the recesses14.(2) As the measuring drum1turns further, the magnetic powder “m” attracted into the recesses14is carried toward the doctor blades19, where surplus magnetic powder “m” is removed from over the recesses14by the doctor blades19. Then, the measured-out amounts of magnetic powder “m” in the recesses14are carried toward the transfer zone between the measuring drum1and the sealing drum4.(3) When the measured-out amounts of magnetic powder “m” reach the transfer zone, the magnetic force of magnets16under the recesses14is cut off by the magnetic-screening plate18and the measured-out amounts of magnetic powder “m” in the recesses14are transferred into recesses44of the sealing drum4by the attraction of the magnets46under the recesses44. Because a first continuous wrapping film “p” is fed onto the periphery of the sealing drum4, the measured-out amounts of magnetic powder “m” transferred into the recesses44sit on the film “p” in the recesses44.(4) As the sealing drum4turns further, the measured-out amounts of magnetic powder “m” in the recesses44are carried toward the wrapping and sealing zone between the sealing drum4and the sealing device5. Because a second continuous wrapping film “q” is fed onto the periphery of the sealing device5, the measured-out amounts of magnetic powder “m” in the recesses44are caught between the first and second films “p” and “q” when the recesses44reaches the wrapping and sealing zone.(5) The sealing device5rotates in synchronism with the sealing drum4. As the sealing drum4and the sealing device5rotate, the first and second continuous films “p” and “q” are caught between the part of the periphery of the sealing drum4around the recesses14and the longitudinal and lateral sealing strips53and54of the sealing device5to be heat-sealed together as shown inFIGS. 7 and 8.

InFIG. 7, S3are the portions sealed by the longitudinal sealing strips53of the sealing device5; S4, by the lateral sealing strips54. Thus, the measured-out amounts of magnetic powder “m” in the recesses44are wrapped up in the film “p/q”.(6) The second sealing device6presses and applies heat to the portions S3and S4again.

The cooling device7cools and solidifies the portions S3and S4.(7) Then, the measured-out amounts of magnetic powder “m” wrapped up in the continuous wrapping film “p/q” are sent to the next step.

Namely, as shown inFIG. 1, the cutter80cuts the continuous film “p/q” in its portions S3and S4into packets, and then the packing machine90packs a certain number of packets at a time.

Referring toFIG. 9, the second embodiment of continuous wrapping machine “A” of the present invention is now described.

In the first embodiment, the relative positions of the measuring drum1and the sealing drum4can be determined freely so long as they can perform their functions. The same is true of the relative positions of the sealing drum4and the sealing device5.

InFIG. 9, the measuring drum1is disposed to the upper left; the sealing drum4, to the lower right. As compared with their arrangement in the first embodiment ofFIG. 2, the measuring drum1is raised and the sealing drum4is lowered. Besides, the sealing device5is disposed not on the top of the sealing drum4as inFIG. 2, but on the right side of the sealing drum4.

In this embodiment, as the measuring and sealing drums1and4and the sealing device5rotate, certain amounts of magnetic powder “m” are measured out by the measuring drum1, transferred from the measuring drum1to the sealing drum4, caught between first and second continuous wrapping films “p” and “q”, and sealed up in the wrapping film “p/q” by the sealing device5.

InFIG. 9, the continuous film “p/q” after being heat-sealed goes vertically upward. It may undergoes the processing in all or some of the following steps while going vertically upward or it may be turned into a horizontal direction by using a guide roller before going through the following steps.

FIG. 10shows still another embodiment of the present invention, wherein the sealing drum4is disposed on the top of the measuring drum1.

In this embodiment too, as the measuring and sealing drums1and4and the sealing device5rotate, certain amounts of magnetic powder “m” are measured out by the measuring drum1, transferred from the measuring drum1to the sealing drum4, caught between first and second continuous wrapping films “p” and “q”, and sealed up in the wrapping film “p/q” by the sealing device5.

InFIG. 10, the continuous film “p/q” after being heat-sealed goes vertically upward. It may undergoes the processing in all or some of the following steps while going vertically upward or it may be turned into a horizontal direction by using a guide roller before going through the following steps.

It is apparent that any arrangement of the measuring drum1, the sealing drum4, and the sealing device5other than the above is possible so long as continuous measuring and wrapping/sealing are possible.

As described above, with the continuous wrapping machine “A” of the present invention, disposable packet body warmers can continuously produced by measuring out certain amounts of magnetic powder “m” and wrapping and sealing them in films “p” and “q”, all the measuring and wrapping/sealing done on the measuring and sealing drums1and4. Therefore, time lag or positional slippage does not occur, dispensing with timing gear. Thus, the measuring and wrapping/sealing of magnetic powder “m” can be done continuously, easily, and efficiently. Besides, because the main bulky components of the continuous wrapping machine “A” are only the measuring and sealing drums1and4, the continuous wrapping machine A is relatively compact.

The material “m” of disposable pocket body warmers mentioned above is just an example of magnetic powders which the continuous wrapping machine of the present invention can handle. Therefore, the continuous wrapping machine and the continuous wrapping method of magnetic powder are applicable to any industrial fields.