Mixer drum apparatus having blades and inlet seal

A mixer drum apparatus to stir material to be stored includes a freely-rotatable drum having an opening end opened at one end to receive the material to be stored therein, a plurality of spirally-shaped blades provided inside the drum to have a phase difference, and an inlet seal provided at the opening end of the drum and connected partially to the blades. The inlet seal located between the blades forms an opening causing the material to be stored to pass through.

RELATED APPLICATIONS

The present application is a National Phase of International Application Number PCT/JP2012/070169, filed Aug. 8, 2012, and claims priority from Japanese Application Number 2011-257640 Nov. 25, 2011.

TECHNICAL FIELD

The present invention relates to a mixer drum apparatus to stir material to be stored such as ready-mixed concrete.

BACKGROUND ART

JP8-40136A discloses a mixer drum apparatus mounted on a concrete mixer truck. This mixer drum apparatus includes a rotating drum, a hopper that directs charged ready-mixed concrete to the drum, an inlet seal that is provided at an opening end of the drum and is connected to the hopper, and a pair of blades that spirally extend from the opening end of the drum to the front side of the concrete mixer truck (back side of the drum).

The inlet seal has an inlet seal pipe that is connected to an outlet of the hopper, and a pair of inlet seal panels that extend from the inlet seal pipe to the back side of the drum to be connected to inner peripheries of the blades.

When charging the ready-mixed concrete, the inlet seal pipe directs the ready-mixed concrete that is charged to the hopper to the back side of the drum.

At the time of stirring or mixing with the ready-mixed concrete being loaded closer to a maximum load, the inlet seal panels receive the ready-mixed concrete that is over the inner peripheries of the blades in the vicinity of the opening end of the drum, thereby preventing the ready-mixed concrete from being discharged from the opening end of the drum.

SUMMARY OF THE INVENTION

According to the above-described conventional mixer drum apparatus, however, the inlet seal panels are provided over the inner peripheries of the pair of blades that are arranged in a front-to-rear direction in the vicinity of the opening end of the drum, and space between the blades arranged in the front-to-rear direction is covered by the inlet seal panels like a tunnel. This makes it likely that the ready-mixed concrete adheres between the pair of blades, and makes it difficult to clean the ready-mixed concrete adhered between the blades, at the time of cleaning inside the drum.

It is an object of the present invention to provide a mixer drum apparatus in which material to be stored, such as ready-mixed concrete, is less likely to adhere between blades, and is capable of improving cleaning performance.

According to one aspect of the present invention, a mixer drum apparatus to stir material to be stored is provided which comprises a freely-rotatable drum having an opening end opened at one end to receive the material to be stored therein; a plurality of spirally-shaped blades provided inside the drum to have a phase difference; and an inlet seal provided at the opening end of the drum and connected partially to the blades, wherein the inlet seal located between the blades forms an opening causing the material to be stored to pass through.

Embodiments of the present invention and advantages thereof are described in detail below with reference to the accompanying drawings.

EMBODIMENTS OF THE INVENTION

A first embodiment will be explained with reference toFIG. 1toFIG. 6.

FIG. 1is a side view showing schematic structure of a concrete mixer truck1. The concrete mixer truck1for loading ready-mixed concrete is equipped with a mixer drum apparatus9to stir the ready-mixed concrete on a vehicle body2.

The mixer drum apparatus9includes supporting units3and4that are provided in the front and in the rear of the vehicle body2, a drum10that is supported by the supporting units3and4freely-rotatable around a rotation center axis O, and a not-shown driving unit that transmits power of an engine to the drum10. The mixer drum apparatus9drives the drum10to rotate in both normal and reverse rotation directions.

The hollow spindle-shaped drum10has a cylindrical portion17that is provided at the center thereof, a front conical portion16that reduces its diameter from the cylindrical portion17to the front of the concrete mixer truck (left side inFIG. 1), and a rear conical portion18that reduces its diameter from the cylindrical portion17to the rear of the concrete mixer truck (right side inFIG. 1).

In the rear of the drum10, an opening end11for charging and discharging the ready-mixed concrete (charging and discharging port) is provided. The drum10is arranged in such a manner that its rotation center axis O is tilted relative to a horizontal line. Therefore, the opening end11of the drum10opens diagonally upward.

A hopper5for charging the ready-mixed concrete is provided in the upper rear of the opening end11of the drum10. An inlet seal40is provided inside the opening end11of the drum10. The ready-mixed concrete charged to the hopper5is guided by the inlet seal40from the opening end11of the drum10into the drum10.

A scoop6and a chute7are provided in the lower rear of the opening end11of the drum10. The ready-mixed concrete discharged from the opening end11is guided by the scoop6to the chute7, and discharged by the chute7in a predetermined direction.

Inside the drum10, a first blade20and a second blade30, each of which has a belt shape and projects from an inner wall12to extend spirally, are provided. A pair of first blade20and second blade30, each extending in the spiral belt shape, has a phase difference of 180° to each other about the rotation center axis O.

The first blade20has a spiral-shaped outer periphery (base end)25that is connected to the inner wall12of the drum10, and a spiral-shaped inner periphery (tip end)24that is extended from the outer periphery25toward the inside of the drum10. Similarly, the second blade30has a spiral-shaped outer periphery (base end)35that is connected to the inner wall12of the drum10, and a spiral-shaped inner periphery (tip end)34that is extended from the outer periphery35toward the inside of the drum10.

At the time of charging, stirring and mixing the ready-mixed concrete to and in the drum10, the drum10is driven to rotate normally and rotated in a counterclockwise direction viewed from the rear (right end side inFIG. 1). The ready-mixed concrete in the drum10is transferred from the rear to the front of the drum10(from the right to the left inFIG. 1) by the rotating first blade20and second blade30. Thus, the ready-mixed concrete is stirred and mixed and its solidification is prevented.

At the time of discharging the ready-mixed concrete from the drum10, the drum10is driven to rotate reversely and rotated in a clockwise direction viewed from the rear. The ready-mixed concrete in the drum10is transferred from the front to the rear of the drum10by the rotating first blade20and second blade30and discharged from the opening end11of the drum10.

InFIG. 2, the first blade20is illustrated by broken lines and the second blade30is illustrated by solid lines. The first blade20in the spiral belt shape has a tapered first blade tip end portion21that extends to the vicinity of the opening end11of the drum10, and the second blade30in the spiral belt shape has a tapered second blade tip end portion31that extends to the vicinity of the opening end11of the drum10. The first blade tip end portion21and the second blade tip end portion31reduce in height with respect to the inner wall12of the drum10gradually from the front side (back side) of the drum10toward the opening end11.

As shown inFIG. 3andFIG. 4, a pair of auxiliary blades29and39that extend from the inner wall12is provided in the vicinity of the opening end11of the drum10. The auxiliary blades29and39are arranged to have a phase difference of 180° with respect to each other and to have a predetermined phase difference with respect to the first blade tip end portion21and the second blade tip end portion31, respectively.

When the drum10is rotated reversely to discharge the ready-mixed concrete, the ready-mixed concrete is transferred to the vicinity of the opening end11of the drum10by the first blade20and the second blade30, and pushed out from the opening end11of the drum10to the scoop6by the tapered first blade tip end portion21and second blade tip end portion31and the auxiliary blades29and39.

Hereinafter, structure of the inlet seal40will be explained.FIG. 5is an expanded view of the inlet seal40, andFIG. 6is a perspective view of the inlet seal40. The inlet seal40has an inlet seal pipe41having an annular shape, and a first inlet seal panel42and a second inlet seal panel43each extending in a curved triangular plate shape from the inlet seal pipe41.

The inlet seal pipe41is formed to have the annular shape around the rotation center axis O. An outlet (not shown) of the hopper5is connected to an opening end of the inlet seal pipe41. An inlet space28defined inside the inlet seal pipe41communicates with the hopper5to introduce the ready-mixed concrete.

When the drum10rotates normally to charge the ready-mixed concrete, the ready-mixed concrete charged to the hopper5is guided by the inlet seal pipe41to the front side (back side) of the drum10over the first blade tip end portion21and the second blade tip end portion31.

The first inlet seal panel42and the second inlet seal panel43are arranged to have a phase difference of 180° to each other about the rotation center axis O. Each of the first inlet seal panel42and the second inlet seal panel43is formed to have the curved triangular plate shape extending to connect the front end of the inlet seal pipe41and the inner peripheries24and34of the first blade20and the second blade30, respectively.

The inlet seal pipe41, the first inlet seal panel42and the second inlet seal panel43are separately formed by a metal plate and connected to each other by welding and the like. Incidentally, the inlet seal pipe41, the first inlet seal panel42and the second inlet seal panel43may be formed as one unit.

When the drum10is rotated normally to stir or mix the ready-mixed concrete, with the ready-mixed concrete being loaded closer to a maximum load, the ready-mixed concrete that is over the inner peripheries24and34of the first blade20and the second blade30gets onto the first inlet seal panel42and the second inlet seal panel43, in the vicinity of the opening end11of the drum10. This makes it possible to prevent the ready-mixed concrete from being discharged from the opening end11of the drum10to the scoop6.

Incidentally, according to a conventional concrete mixer truck, inlet seal panels142and143of the inlet seal are formed in a conical shape (tapered cylindrical shape) that increases its diameter along the rear conical portion of the drum, and the pair of blades arranged in the front-to-rear direction in the vicinity of the opening end of the drum is formed to have approximately the same extension height, as shown by two-dotted chain lines inFIG. 2. Therefore, it was necessary to provide the inlet seal panels142and143over a wide area in the vicinity of the opening end of the drum, in order to prevent the ready-mixed concrete from getting over the blades and being discharged. As a result, space between the blades arranged in the front-to-rear direction is covered by the inlet seal panels142and143like a tunnel, which makes it likely that the ready-mixed concrete adheres between the blades, and makes it difficult to clean the ready-mixed concrete adhered between the blades at the time of cleaning the concrete mixer truck.

For this reason, the inlet seal40of this embodiment is structured to make the space open between the first blade20and the second blade30that are arranged in the direction of the rotation center axis O of the drum10, and not to cover the space between the first blade20and the second blade30like a tunnel.

Each of regions A and B, as shown inFIG. 4andFIG. 5, is set to have an angular range of 180° about the rotation center axis O, with a center line Z at the end of the drum forming a border therebetween. In the region A, the first blade tip end portion21exists as a portion of the first blade20separated from the inlet seal pipe41. In the region B, the second blade tip end portion31exists as a portion of the second blade30separated from the inlet seal pipe41.

An annular outlet space27is defined between the inlet seal pipe41and the opening end11of the drum10. The outlet space27opens toward the outside of the drum10as the first blade tip end portion21and the second blade tip end portion31are separated from the inlet seal pipe41in the regions A and B.

The first inlet seal panel42is arranged in the region A so as not to cover the space between the first blade20and the second blade30like a tunnel. The second inlet seal panel43is arranged in the region B so as not to cover the space between the first blade20and the second blade30like a tunnel.

A first opening26is defined in the region B by a first seal side portion42aof the first inlet seal panel42, to make the space open between the first blade20and the second blade30(refer toFIG. 3andFIG. 4).

A second opening36is defined in the region A by a second seal side portion43aof the second inlet seal panel43, to make the space open between the first blade20and the second blade30(refer toFIG. 3andFIG. 4).

Thereby, the space between the first blade20and the second blade30that are arranged in the front-to-rear direction is not covered by the first inlet seal panel42and the second inlet seal panel43like a tunnel. This makes it difficult for the ready-mixed concrete to adhere between the first blade20and the second blade30, and makes it easy to clean the space between the first blade20and the second blade30at the time of cleaning inside the drum10.

The inlet seal pipe41has a first blade connecting portion24aand a second blade connecting portion34athat are connected to the inner peripheries (tip ends)24and34of the first blade20and the second blade30.

The first inlet seal panel42has a front side seal end portion (front end portion)42bthat extends from the inlet seal pipe41to the back side (front) of the drum10to be connected to the inner periphery34of the second blade30.

Similarly, the second inlet seal panel43has a front side seal end portion (front end portion)43bthat extends from the inlet seal pipe41to the back side (front) of the drum10to be connected to the inner periphery24of the first blade20.

The center line Z at the end of the drum is a line orthogonal to the rotation center axis O of the drum10. The first inlet seal panel42has the first seal side portion42athat touches the center line Z at the end of the drum and extends in approximately parallel to the rotation center axis O of the drum10. The second inlet seal panel43has the second seal side portion43athat touches the center line Z at the end of the drum and extends in approximately parallel to the rotation center axis O of the drum10.

The expanded view inFIG. 5shows the first inlet seal panel42and the second inlet seal panel43according to this embodiment in solid lines. Supposing that the lines extending from the inlet seal pipe41in approximately parallel to the rotation center axis O of the drum10are reference lines L1and L2, the first seal side portion42aand the second seal side portion43aare formed to extend along the reference lines L1and L2in an approximately linear manner.

The first inlet seal panel42is formed in the curved triangular plate shape that extends to connect the first seal side portion42a, a front end41aof the inlet seal pipe41, and the inner periphery34of the second blade30. The second blade connecting portion34abecomes a sharply-angled tip end (vertex) of the first inlet seal panel42. The first seal side portion42ais offset with respect to the second blade connecting portion34atoward the second blade tip end portion31(refer toFIG. 5). This makes it possible to prevent the first inlet seal panel42from blocking the space between the first blade20and the second blade30arranged in the front-to-rear direction. It should be noted that the first seal side portion42amay be connected to the second blade connecting portion34a.

Similarly, the second inlet seal panel43is formed in the curved triangular plate shape that extends to connect the second seal side portion43a, the front end41aof the inlet seal pipe41, and the inner periphery24of the first blade20. The first blade connecting portion24abecomes a sharply-angled tip end (vertex) of the second inlet seal panel43. The second seal side portion43ais offset with respect to the first blade connecting portion24atoward the first blade tip end portion21(refer toFIG. 5). This makes it possible to prevent the second inlet seal panel43from blocking the space between the first blade20and the second blade30arranged in the front-to-rear direction. It should be noted that the second seal side portion43amay be connected to the first blade connecting portion24a.

As the first inlet seal panel42and the second inlet seal panel43are not provided in the first opening26and the second opening36, the space between the first blade20and the second blade30arranged in the front-to-rear direction is opened.

The first opening26is defined spirally among the first seal side portion42aof the first inlet seal panel42, the inner periphery24of the first blade20, and the inner periphery34of the second blade30.

The second opening36is defined spirally among the second seal side portion43aof the second inlet seal panel43, the inner periphery34of the second blade30, and the inner periphery24of the first blade20.

The first opening26and the second opening36are juxtaposed in a circumferential direction to have a phase difference of 180° to each other about the rotation center axis O of the drum10, each of which has a shape spirally cutting off a semicylindrical surface having the rotation center axis O at the center.

As the first inlet seal panel42and the second inlet seal panel43do not form the tunnel-shaped space between the first blade20and the second blade30, it is difficult for the ready-mixed concrete (material to be stored) to adhere between the first blade20and the second blade30. Moreover, as the space between the first blade20and the second blade30is opened, it is easy to clean between the first blade20and the second blade30by spraying water thereon, at the time of cleaning the inside of the drum10.

In the expanded view inFIG. 5, the inlet seal panels142and143according to the conventional apparatus are illustrated by two-dotted chain lines. While the first inlet seal panel42and the second inlet seal panel43according to this embodiment make the space open between the first blade20and the second blade30arranged in the front-to-rear direction, the inlet seal panels142and143according to the conventional apparatus are provided to cover the space between the first blade20and the second blade30arranged in the front-to-rear direction like a tunnel.

The first inlet seal panel42and the second inlet seal panel43according to this embodiment are extended in approximately parallel to the rotation center axis O of the drum10, and are formed along a cylindrical surface that is continued from the inlet seal pipe41.

The extension heights of the first blade20and the second blade30with respect to the inner wall12of the drum10are set according to the shapes of the first inlet seal panel42and the second inlet seal panel43so that the front side seal end portions (front end portions)42band43bof the first inlet seal panel42and the second inlet seal panel43are connected without a difference in level to the inner peripheries24and34of the first blade20and the second blade30.

Thereby, in the vicinity of the opening end11of the drum10, the heights of the first blade20and the second blade30are greater on the front side (back side) that is far from the opening end11, than on the back side that is closer to the opening end11. This makes it possible to prevent the ready-mixed concrete from getting over the inner peripheries24and34of the first blade20and the second blade30, in the vicinity of the opening end11of the drum10.

When the drum10is rotated normally to stir or mix the ready-mixed concrete, with the ready-mixed concrete being loaded closer to the maximum load, the ready-mixed concrete that gets over the inner peripheries24and34of the first blade20and the second blade30gets onto the first inlet seal panel42, the second inlet seal panel43and the inside of the inlet seal40. This makes it possible to prevent the ready-mixed concrete from dropping to the opening end11side (outlet space27) of the drum10. Namely, in the area where the first inlet seal panel42and the second inlet seal panel43are not provided, the ready-mixed concrete that gets over the inner peripheries24and34of the first blade20and the second blade30drops to the space between the first blade20and the second blade30arranged in the front-to-rear direction, and is transferred back to the front side (back side) of the drum10by the rotating first blade20and the second blade30. This makes it possible to prevent the ready-mixed concrete from flowing toward the opening end11side (outlet space27) of the drum10. Therefore, it is possible for the drum10to secure the load capacity equal to that of the conventional apparatus having the large inlet seal.

Next, a second embodiment will be explained with reference toFIG. 7toFIG. 10.

FIG. 7is a perspective view of the drum viewed from a diagonally rear left direction.FIG. 8is a cross-sectional view showing schematic structure of the mixer drum apparatus9.FIG. 9is an expanded view of the inlet seal40.FIG. 10is a perspective view of the inlet seal40. Structure of the mixer drum apparatus of this embodiment is basically the same as that of the first embodiment, and hence explanations are given only to the parts that are different from those of the first embodiment. Incidentally, the identical reference signs are given to the elements identical to those of the first embodiment.

The first inlet seal panel42has a first extended portion42ethat extends along the inner peripheries24and34of the first blade20and the second blade30in front. The second inlet seal panel43has a second extended portion43ethat extends along the inner peripheries24and34of the first blade20and the second blade30in front.

The first inlet seal panel42has a first seal side portion42cthat extends to curve along the reference line L1and the inner periphery34of the second blade30. The second inlet seal panel43has a second seal side portion43cthat extends to curve along the reference line L2and the inner periphery24of the first blade20.

Respective rear ends42gand43gof the first extended portion42eand the second extended portion43eare arranged at the front end41aof the inlet seal pipe41. Respective front ends42hand43hof the first extended portion42eand the second extended portion43eare arranged at positions separated from the reference lines L1and L2of the inner peripheries24and34of the first blade20and the second blade30toward the front (back side).

Extension widths of the first extended portion42eand the second extended portion43e, extending in a rotation circumferential direction of the drum10from the reference lines L1and L2, gradually increase from the rear ends42gand43gtoward the front (back side).

Extension widths of the first extended portion42eand the second extended portion43e, extending in a rotation axis direction of the drum10from the inner peripheries24and34of the first blade20and the second blade30, gradually increase from the front ends42hand43htoward the rear (opening end11side).

At the time of stirring or mixing, the ready-mixed concrete that gets over the inner peripheries24and34of the first blade20and the second blade30gets onto the first extended portion42eand the second extended portion43eof the first inlet seal panel42and the second inlet seal panel43. This makes it possible to prevent the ready-mixed concrete from flowing toward the opening end11side (outlet space27) of the drum10. Therefore, it is possible for the drum10to secure the load capacity equal to or greater than that of the conventional apparatus having the large inlet seal.

In the expanded view inFIG. 9, the first inlet seal panel42and the second inlet seal panel43of this embodiment are illustrated by solid lines, and the first inlet seal panel142and the second inlet seal panel143of the conventional apparatus are illustrated by two-dotted chain lines. As the first inlet seal panel42and the second inlet seal panel43are structured to make the space open between the first blade20and the second blade30arranged in the front-to-rear direction, it is less likely that the ready-mixed concrete (material to be stored) adheres between the first blade20and the second blade30, as compared with the first inlet seal panel142and second inlet seal panel143of the conventional apparatus. Moreover, as the space between the first blade20and the second blade30is opened, it is easy to clean between the first blade20and the second blade30by spraying water thereon, at the time of cleaning the inside of the drum10.

According to this embodiment as described thus far, it is easy to clean the inside of the drum10, similarly to the first embodiment, and also it is possible to increase the load capacity to be greater than that of the first embodiment. When the load capacity is the same as that of the first embodiment, it is possible to downsize the drum10.

Next, a third embodiment will be explained with reference toFIG. 11.

FIG. 11is a perspective view of the inlet seal40. Structure of the mixer drum apparatus of this embodiment is basically the same as that of the first embodiment, and hence explanations are given only to the parts that are different from those of the first embodiment. Incidentally, the identical reference signs are given to the elements identical to those of the first embodiment.

The inlet seal40does not have the inlet seal pipe41of the first embodiment, and is formed by the first inlet seal panel42and the second inlet seal panel43only, each having the curved triangular plate shape.

The first inlet seal panel42is formed in the curved triangular plate shape that extends to connect the first blade connecting portion24aand the inner periphery34of the second blade30.

The first inlet seal panel42has the first seal side portion42athat extends from the first blade connecting portion24ain approximately parallel to the rotation center axis O of the drum10, the front side seal end portion42bthat is connected to the inner periphery34of the second blade30, and a backside seal end portion42cthat connects the first blade connecting portion24aand the second blade connecting portion34a. The first blade connecting portion24abecomes a sharply-angled tip end (vertex) of the second inlet seal panel43.

The second inlet seal panel43is formed in the curved triangular plate shape that extends to connect the second blade connecting portion34aand the inner periphery24of the first blade20.

The second inlet seal panel43has the second seal side portion43athat extends from the second blade connecting portion34ain approximately parallel to the rotation center axis O of the drum10, the front side seal end portion43bthat is connected to the inner periphery24of the first blade20, and a backside seal end portion43cthat connects the second blade connecting portion34aand the blade connecting portion24aof the first blade20. The second blade connecting portion34abecomes a sharply-angled tip end (vertex) of the first inlet seal panel42. Incidentally, the first inlet seal panel42and the second inlet seal panel43may be structured to include the first extended portion42eand the second extended portion43ethat are extended along the inner peripheries24and34of the first blade20and the second blade30in front (refer toFIG. 8).

Thereby, the first inlet seal panel42and the second inlet seal panel43, each having the curved triangular plate shape, do not cover the space between the first blade20and the second blade30that are arranged in the front-to-rear direction like a tunnel. The first seal side portion42adefines the first opening26that makes the space open between the first blade20and the second blade30, and the second seal side portion43adefines the second opening36that makes the space open between the first blade20and the second blade30.

At the time of stirring or mixing the mixer drum apparatus9, the ready-mixed concrete that gets over the inner peripheries24and34of the first blade20and the second blade30gets onto the first inlet seal panel42and the second inlet seal panel43, in the vicinity of the opening end11of the drum10. This makes it possible to prevent the ready-mixed concrete from dropping to the opening end11side (outlet space27) of the drum10. Namely, in the area where the first inlet seal panel42and the second inlet seal panel43are not provided, the ready-mixed concrete getting over the inner peripheries24and34of the first blade20and the second blade30drops to the space between the first blade20and the second blade30arranged in the front-to-rear direction, and is transferred back to the front side (back side) of the drum10by the rotating first blade20and the second blade30. This makes it possible to prevent the ready-mixed concrete from flowing toward the opening end11side (outlet space27) of the drum10.

In the area where the first inlet seal panel42and the second inlet seal panel43are not provided, the space between the first blade20and the second blade30that are arranged in the front-to-rear direction is opened. As the first inlet seal panel42and the second inlet seal panel43do not form the tunnel-shaped space between the first blade20and the second blade30, it is difficult for the ready-mixed concrete to adhere between the first blade20and the second blade30. Moreover, as the space between the first blade20and the second blade30is opened, it is easy to clean between the first blade20and the second blade30by spraying water thereon, at the time of cleaning the inside of the drum10.

The third embodiment does not have the inlet seal pipe as described above, and therefore, a hopper on a facility side can be inserted in the drum10when charging the ready-mixed concrete. Thus, it is possible to accept the specification that does not have the hopper at the inlet of the drum10.

Outlines, operations and effects of the respective embodiments will be explained.

(A) The mixer drum apparatus9to stir the material to be stored includes the freely-rotatable drum10that has the opening end11opened at one end and receives the material to be stored therein, the plurality of blades20and30that are spirally-shaped and provided inside the drum10to have the phase difference, and the inlet seal40that is provided at the opening end11of the drum10and is connected partially to the blades20and30. The inlet seal40located between the blades20and30forms the openings26and36causing the material to be stored to pass through (refer toFIG. 1toFIG. 9).

When charging the ready-mixed concrete according to the above-described structure, the ready-mixed concrete (material to be stored) that is charged into the drum10is guided by the inlet seal40to the front side (back side) of the drum10over the blade tip end portions21and31.

When the drum10is rotated normally to stir or mix the ready-mixed concrete, the ready-mixed concrete that gets over the inner peripheries24and34of the blades20and30gets onto the inlet seal40, in the vicinity of the opening end11of the drum10. This makes it possible to prevent the ready-mixed concrete from being discharged from the opening end11of the drum10.

Meanwhile, when the drum10is rotated reversely to discharge the ready-mixed concrete, the ready-mixed concrete is transferred from the front to the rear of the drum10by the rotating blades20and30and discharged from the opening end11of the drum10.

The openings26and36that are formed by the inlet seal40make the space open between the blades20and30that are arranged in the rotation center axis O direction of the drum10, and therefore, the space between the blades20and30arranged in the front-to-rear direction is not covered by the inlet seal40like a tunnel. Thereby, it is difficult for the ready-mixed concrete (material to be stored) to adhere between the blades20and30that are arranged in the front-to-rear direction of the drum10, and it is easy to clean between the blades20and30that are arranged in the front-to-rear direction of the drum10, at the time of cleaning the inside of the drum10. As a result of this, it is possible to prevent deterioration of stirring and mixing performance and discharging performance of the mixer drum apparatus9due to the material adhered to the blades20and30.

(B) The inlet seal40has the seal side portions42aand43athat define the openings26and36to make the space open between the blades20and30arranged in the rotation center axis O direction of the drum10(in the front-to-rear direction of the drum10), and the seal side portions42aand43aextend in the approximately linear manner along the reference lines L1and L2extending in approximately parallel to the rotation center axis O of the drum10(refer toFIG. 5).

According to the above-described structure, the seal side portions42aand43amake the space open between the blades20and30arranged in the front-to-rear direction of the drum10. Thereby, it is difficult for the ready-mixed concrete (material to be stored) to adhere between the blades20and30that are arranged in the front-to-rear direction of the drum10, and it is easy to clean between the blades20and30that are arranged in the front-to-rear direction of the drum10, at the time of cleaning the inside of the drum10.

As the seal side portions42aand43aextend in approximately parallel to the rotation center axis O of the drum10, the heights of the blades20and30are formed greater on the front side (back side) that is far from the opening end11, than on the back side that is closer to the opening end11. This makes it possible to prevent the ready-mixed concrete from getting over the inner peripheries24and34of the first blade20and the second blade30, in the vicinity of the opening end11of the drum10. Therefore, it is possible for the drum10to secure the load capacity equal to that of the conventional apparatus having the large inlet seal.

(C) The inlet seal40has the blade connecting portions24aand34athat are connected to the blades20and30, in the vicinity of the opening end11of the drum10, and is formed to have the curved triangular plate shapes extending from the blade connecting portions24aand34ato the blades30and20located on the back side of the drum10(refer toFIG. 11).

According to the above-described structure, the inlet seal40in the curved triangular plate shapes does not have the inlet seal pipe. Therefore, the hopper on the facility side can be inserted in the drum10when charging the ready-mixed concrete. Thus, it is possible to accept the specification that does not have the hopper at the inlet of the drum10.

Moreover, as the inlet seal40does not have the annular inlet seal pipe41, simplification of the structure is made possible.

(D) The inlet seal panels42and43have the extended portions42eand43ethat are formed along both of the seal side portions42aand43a(reference lines L1and L2) and the blades20and30(refer toFIG. 7toFIG. 10).

At the time of stirring or mixing according to the above-described structure, the ready-mixed concrete that gets over the inner peripheries24and34of the blades20and30gets onto the extended portions42eand43eof the inlet seal panels42and43. This makes it possible to prevent the ready-mixed concrete from flowing toward the opening end11side (outlet space27) of the drum10. Thus, it is possible to realize both of the cleaning performance and loading performance of the drum10.

(E) The inlet seal40has the annular inlet seal pipe41that is connected to the blades20and30, and the inlet seal panels42and43that extend from the inlet seal pipe41to the blades20and30arranged on the back side of the drum10, in the vicinity of the opening end11of the drum10(refer toFIG. 1toFIG. 6).

According to the above-described structure, the charged ready-mixed concrete is guided by the inlet seal pipe41to the inside of the drum10. Further, at the time of stirring or mixing, the ready-mixed concrete that gets over the inner peripheries24and34of the blades20and30gets onto the inlet seal panels42and43, in the vicinity of the opening end11of the drum10. This makes it possible to prevent the ready-mixed concrete from being discharged from the opening end11of the drum10.

Moreover, the inlet seal panels42and43make the space open between the blades20and30, and therefore, the space between the blades20and30arranged in the front-to-rear direction is not covered by the inlet seal40like a tunnel. Thereby, it is difficult for the ready-mixed concrete (material to be stored) to adhere between the blades20and30that are arranged in the front-to-rear direction of the drum10, and it is easy to clean between the blades20and30at the time of cleaning the inside of the drum10.

The embodiments of the present invention described above are merely illustration of some application examples of the present invention and not of the nature to limit the technical scope of the present invention to the specific constructions of the above embodiments.

For example, the mixer drum apparatus9according to the above-described embodiments has the pair of first blade20and second blade30, but it may be structured to have only one blade. In this case, the inlet seal has one inlet seal panel that has the seal side portion defining the opening to make the space open in one blade arranged in the rotation center axis O direction.

Alternatively, the mixer drum apparatus9may include three or more blades. In this case, the inlet seal has three or more inlet seal panels that have the seal side portions forming three or more openings for making the space open in the three or more blades arranged in the rotation center axis O direction.

Moreover, the material to be stored received in the mixer drum apparatus9is not limited to the ready-mixed concrete, and other material to be stored may be received.

The present application claims a priority based on Japanese Patent Application No. 2011-257640 filed with the Japan Patent Office on Nov. 25, 2011, all the contents of which are hereby incorporated by reference.