CA2987560A1

CA2987560A1 - Mixer

Info

Publication number: CA2987560A1
Application number: CA2987560A
Authority: CA
Inventors: Tsukasa HEISHI; Takahiro Iwamoto
Original assignee: KYB Corp
Current assignee: KYB Corp
Priority date: 2015-06-19
Filing date: 2016-04-27
Publication date: 2016-12-22
Also published as: NZ735880A; AU2016280992A1; WO2016203854A1; JP5990304B1; JP2017007166A

Abstract

Provided is a mixer which can satisfactorily supply electric power to electrical equipment that rotates together with a mixer drum. This mixer (10J) is provided with: a support part (11); a mixer drum (10); a slump sensor (16); a power generator (30); and a power line (14). The mixer drum (10) is pivotally supported by the support part (11) and rotates about a rotational axis (10G). The slump sensor (16) is attached to the mixer drum (10) and rotates together with the mixer drum (10). The power generator (30) has: a power generation part (30D) which is attached to the mixer drum (10) and which rotates together with the mixer drum (10); and a shaft part (30B) which protrudes from the power generation part (30D) and which is freely rotatable relative to the power generation part (30D). When the shaft part (30B) rotates relative to the power generation part (30D) along with the rotation of the mixer drum (10), the power generator (30) generates electric power to be supplied to the slump sensor (16). The power line (14) connects the power generation part (30D) to the slump sensor (16).

Description

DESCRIPTION
Title of the Invention: MIXER
Technical Field [0001] The present invention relates to a mixer.
Background Art

[0002] Patent Document 1 discloses a conventional mixer. This mixer includes a mixer drum (a drum), a support (a vehicle body), a solar power generator and a plurality of electrical devices (remaining water detective sensors). The mixer drum has an end formed with an opening. The mixer drum is rotatably mounted on the support. The solar power generator is provided on an outer peripheral surface of the mixer drum. The solar power generator receives sunlight to generate electric power while being rotated together with the mixer drum. The plural electrical devices are arranged circumferentially on an inner peripheral surface of the mixer drum. The plural electrical devices are rotated together with the mixer drum. Accordingly, the solar power generator provided on the outer peripheral surface of the mixer drum receives sunlight and generates electric power while being rotated together with the mixer drum, which electric power can be fed to the plural electrical devices in this mixer. In other words, this mixer need not feed power through a power line from the support side to the electrical devices provided at the mixer drum side, with the result that there is no risk of disconnection of a power line to feed the electrical devices.
Prior Art Document Patent Documents

[0003] Patent Document 1: Japanese Patent Application Publication JP 2008-100407 A
Summary of the Invention Problem to Be Overcome by the Invention

[0004] In the mixer of patent document 1, however, electric power is generated by the solar power generator which is subjected to influences from time zones and a surrounding environment such as weather. As a result, there is a possibility that electric power cannot stably be fed to the electrical devices in the mixer depending upon the surrounding environment.

[0005] The present invention was made in view of the above-described circumstances in the conventional art and has an object to provide a mixer which can successfully feed the electrical devices rotated together with a mixer drum.
Means for Overcoming the Problem

[0006] A mixer in accordance with the present invention includes a support, a mixer drum, an electric device, a generator, and a power line. The mixer drum is supported by the support to be rotatable about a rotation axis. The electric device is mounted on the mixer drum to be rotatable together with the mixer drum.
The generator includes a power generation part and a shaft. The power generation part is mounted on the mixer drum to be rotatable together with the mixer drum. The shaft protrudes from the power generation part to be rotatable relative to the power generation part. The generator generates electric power to be fed to the electric device when the shaft is rotated relative to the power generation part with rotation of the mixer drum. The power line connects the power generation part and the electric device.

[0007] The power generation part of the mixer in accordance with the invention is fixed to an outer surface of the mixer drum to be rotatable on a circumference about the rotation axis of the mixer drum. Furthermore, the shaft of the generator includes a rotation body coupled to a distal end thereof. Furthermore, the support has a contacted part with which the rotation body is brought into contact while being rotated.

[0008] The contacted part of the mixer in accordance with the invention is a cylindrical part formed to be coaxial with the rotation axis.

[0009] The generator of the mixer in accordance with the invention is mounted on the mixer drum so that the rotation body is swung radially with respect to the rotation axis of the mixer drum.
Furthermore, the generator has an elastic member imparting an elastic force in a direction such that the rotation body abuts against the contacted part.

[0010] The mixer drum of the mixer in accordance with the invention has a drive shaft provided coaxially with the rotation axis. Furthermore, the power generation part is coupled to the drive shaft of the mixer drum to be rotatable about the rotation axis. Furthermore, the shaft is fixed to the support and inserted into the power generation part coaxially with the rotation axis.
Brief Description of the Drawings

[0011] Fig. 1 is a schematic view of a mixer truck of a first embodiment;
Fig. 2 is a schematic view of the mixer in the first embodiment;
Fig. 3 is a schematic view of a power generation part in the first embodiment;

Fig. 4 is a schematic view of a major part of the mixer in a second embodiment; and Fig. 5 is a schematic view of a major part of the mixer in a third embodiment.
Best Mode for Carrying Out the Invention

[0012] First to third embodiments of the mixer truck with a mixer in accordance with the invention being mounted on the upper side of the mount of the body will be described with reference to the drawings.

[0013] <First Embodiment>
Referring to Fig. 1, the mixer truck of the first embodiment includes a body 50, a mixer 10J, a hopper 50C and a chute 50D.

[0014] The body 50 has a cabin 50A and a mount 50F. The cabin 50A is provided at the front side of the body 50 (a front-back direction corresponds to a left-right direction as viewed in Fig.
1. The same shall apply hereinafter.). The mount 5OF is provided at the rear side of the cabin 50A. An engine (not illustrated) to run the body 50 is provided at a lower side of the cabin 50A
(an up-down direction corresponds to an up-down direction as viewed in Fig. 1. The same shall apply hereinafter.).

[0015] The mixer 10J includes a mixer drum 10, a support 11, a generator 30, a slump sensor 16 serving as an electric device, a power line 14, and a contacted part 13, as illustrated in Fig.
2.

[0016] The mixer drum 10 has a drum body 10A, a drive shaft 103, two drum blades 10C and a roller ring 10D. The drum body 10A is formed into a cylindrical shape. The drum body 10A has two ends one of which is provided with an opening 10E. The other end of the drum body 10A located at the inner side as viewed from the one end is closed by a closure part 10F. The drive shaft 10B is connected to a central part of the closure part 1OF and extends outward from the drum body 10A. The drive shaft 10B extends on a rotational axis 10G of the mixer drum 10.

[0017] The drive shaft 10B is connected to a speed reducer (not illustrated) . The speed reducer is connected to a hydraulic motor (not illustrated). The hydraulic motor is connected via piping (not illustrated) to a hydraulic pump (not illustrated). The hydraulic pump is connected to an engine (not illustrated) mounted on the body. Thus, a rotative force of the engine is transmitted to the drive shaft 10B via the hydraulic pump, the piping, the hydraulic motor and the speed reducer, so that the mixer drum 10 is rotated.

[0018] The drum blades 10C are fixed along an inner peripheral surface of the drum body 10A in a spiral manner with a predetermined space from each other. In other words, the drum blades 10C are rotated together with the drum body 10A. The roller ring 10D is annular in shape and is provided so as to go round an outer surface of the drum body 10A at the opening 10E side.

[0019] The mixer drum 10 is mounted on the support 11 in a forwardly inclined posture in which the opening 10E is raised higher than the closure part 1OF with the opening 10E being located above the rear support 11B so as to be rotatable about a rotation axis 10G. In more detail, the support 11 includes a plurality of rollers 11A which is provided on a rear end of the support 11 and supports the roller ring 10D of the mixer drum 10 from below. Furthermore, the support 11 includes a front end which supports the drive shaft 103 of the mixer drum 10. Thus, the support 11 axially support the mixer drum 10 so that the mixer drum 10 is rotatable about the rotational axis 10G.

[0020] The generator 30 includes a power generation part 30D, a spring 30C, and a shaft 30B as illustrated in Figs. 2 and 3.

[0021] The power generation part 30D includes a generator body 30A, right-left side walls 30G, and an upper wall 30H. The generator body 30A extends in a front-back direction of the mixer drum 10. The right-left side walls 30G are paired in the right-left direction (a front and depth direction as viewed in Fig. 3). The right-left side walls 30G are flat plates elongated in the up-down direction. Right and left sides of the rear of the generator body 30A are horizontally sandwiched by the right-left side walls 30G. The rear right and left sides of the generator body 30A are axially supported by the right-left side walls 30G so that a front end of the generator body 30A is swingable in the up-down direction.

[0022] The upper wall 30H includes a first upper wall 30J and a second upper wall 30K. The first upper wall 30J is a flat plate extending in the up-down direction. The first upper wall 30J has right and left lower portions respectively coupled to the right-left side walls 30G. The first upper wall 30J extends upward from upper rear ends of the right-left side walls 30G. The second upper wall 30K is a flat plate elongated in the front-back direction. The second upper wall 30K has an end coupled to an upper end of the first upper wall 30J.

[0023] The spring 30C serving as an elastic member is formed of a metal wire into a coil shape. The spring 30C is formed into the coil shape so that a slight space is defined between each turn of metal wire and an adjacent one. The spring 30C is disposed so as to be elongate in the up-down direction and has two ends one of which is connected to an upper front end of the generator body 30A. The other end of the spring 30C is connected to an underside of the other end of the second upper wall 30K. An elastic force of the spring 300 is imparted downward to the generator body 30A and the shaft 30B which will be described later.

[0024] The shaft 30B includes a shaft body 30E and a rotor 30F
serving as a rotation body. The shaft body 30E is rotatably provided on the generator body 30A and protrudes forward from a front end of the generator body 30A. The rotor 30F is formed into a frustum shape in which a front end has a smaller outer diameter than a rear end. The outer diameters of the front and rear ends of the rotor 30F are larger than the outer diameter of the shaft body 30E. The rotor 30F has a central axis coaxial with a central axis of the shaft body 30E. Furthermore, a distal end of the shaft body 30E is inserted into the rotor 30F. Thus, the rotor 30F is coupled to the distal end of the shaft body 30E.
The shaft body 30E and the rotor 30F both serving as the shaft 30B are rotated together about the central axis relative to the generator body 30A. In other words, the shaft 30B protrudes forward from the front end of the generator body 30A and is rotatable relative to the generator body 30A.
The shaft 303 is rotated relative to the generator body 30A, whereby electric power is generated in the generator body 30A.
The power line 14 has two ends one of which is connected to a rear end of the generator body 30A. Furthermore, the other end of the power line 14 is connected to an operation part 15 of the slump sensor 16 which will be described later.

[0025] In the generator 30, lower ends of the right-left side walls 30G are fixed to a front end of the outer peripheral surface of the mixer drum 10, and the shaft 30B extends forward. The shaft 30B of the generator 30 protrudes forward with respect to the mixer drum 10. Since the front end of the generator body 30A is swingably supported by the right-left side walls 30G, the rotor 30F which serves as the rotation body of the shaft 30B extending forward from the generator body 30A is swung radially with respect to the rotation axis 10G of the mixer drum 10. Furthermore, the elastic force of the spring 300 is imparted to the rotor 30F toward the rotation axis 10G of the mixer drum 10.

[0026] The slump sensor 16 serving as the electric device includes an electrode 12 and the operation part 15. The electrode 12 is provided on an inner peripheral surface of the mixer drum 10.
The operation part 15 is provided on an outer surface of the mixer drum 10. The electrode 12 and the operation part 15 are electrically connected to each other through a through-hole 17 formed through the drum body 10A in a watertight manner. In other words, the slump sensor 15 is mounted on the mixer drum 10 and rotated together with the mixer drum 10. In the slump sensor 16, a slump value is found by the operation part 15 based on predetermined electric characteristic such as a resistance value or an electrostatic capacitance value of the ready-mixed concrete measured using the electrode 12.

[0027] The power line 14 is laid in the mixer drum 10, and the other end thereof is connected to the operation part 15 of the slump sensor 16. Thus, in this mixer truck, the power line 14 electrically connects the generator body 30A of the power generation part 30D and the operation part 15 of the slump sensor 16 serving as the electric device. In other words, in this mixer truck, electric power is fed from the power generation part 30D
to the electric devices through the power line 14.

[0028] The contacted part 13 is coupled to a front end of the support 11. The contacted part 13 is coaxial with the rotation axis 10G of the mixer drum 10 and is a cylindrical part formed around the rotation axis 10G. The elastic force of the spring 30C is imparted to the rotor 30F in a direction such that the outer peripheral surface of the rotor 30F abuts against the outside of the contacted part 13.

[0029] The hopper 50C is fixed to an upper rear end of the support 11. The hopper 50C is formed with an inlet that is open while being spread upward. The hopper 50C has a lower end which is open forwardly downward thereby to be formed into an outlet. The outlet of the hopper 50C communicates with a central part of the opening 10E of the mixer drum 10. The ready-mixed concrete put through the inlet of the hopper 50C is further put into the mixer drum 10 through the outlet of the hopper 50C.

[0030] The chute 50D is supported on the rear end of the support 11 so that a distal end thereof is rotatable about a proximal end thereof in a horizontal direction and in an up-down direction.
In this case, the horizontal direction should not mean a strict horizontal direction but includes a state deviated somewhat from the strict horizontal direction. Thus, the ready-mixed concrete discharged from the mixer drum 10 is guided by the chute 50D to a desired location.

[0031] The mixer 10J, the hopper 50C and the chute 50D as constructed above are mounted at the upper side of the mount 50F
of the body 50 in this mixer truck.

[0032] The working of the mixer 10J of the mixer truck will now be described. The mixer drum 10 of the mixer 10J is rotated about the rotation axis 10G to agitate the ready-mixed concrete put thereinto. In this case, the generator 30 is rotated on the circumference about the rotation axis 10G of the mixer drum 10 with rotation of the mixer drum 10. The outer peripheral surface of the rotor 30F is caused to abut against the outside of the contacted part 13 by the elastic force of the spring 30C, so that the rotor 30F is rotated in contact with the outside of the contacted part 13. In other words, the shaft 30B is rotated with rotation of the mixer drum 10 while being moved around the outside of the contacted part 13. Thus, the electric power can be generated by the generator 30 since the shaft 30B is rotated relative to the generator body 30A.

[0033] Thus, in the mixer 10J of this mixer truck, electric energy can be taken out by making use of the rotative force of the mixer drum 10 which rotates to agitate the ready-mixed concrete. As a result, the mixer 10J can generate electric power by an effective use of the rotative energy of the mixer drum 10 without influences from the ambient environment, such as time of day or weather, and can stably feed the electric power to the slump sensor 16. Furthermore, the mixer 10J does not require a larger mounting area as compared with the case where a solar power generator is mounted, and the generator 30 can easily be mounted on the mixer drum 10. Furthermore, since the electric power is fed from the power generation part 30D mounted on the mixer drum through the power line 14 to the slump sensor 16, the electric power need not be fed from the support 11 side through the power 5 line 14 to the slump sensor 16 provided at the mixer drum 10 side, with the result that electric power can be fed to the slump sensor 16 by a simple circuit.

[0034] Accordingly, the mixer 10J of the mixer truck of the first embodiment can successfully feed electric power to the slump 10 sensor 16 which is mounted on the mixer drum 10 to be rotated together with the mixer drum 10.

[0035] Furthermore, the power generation part 30D of the mixer 10J is fixed to the outer surface of the mixer drum 10 and rotated on the circumference about the rotation axis 10G of the mixer drum 10. Furthermore, the shaft 30B of the generator 30 is provided with the rotor 30F coupled to the distal end of the shaft 30B. Furthermore, the support 11 has the contacted part 13 with which the rotor 30F is brought into contact while being rotated.
Accordingly, the shaft 30B of the generator 30 is rotated relative to the power generation part 30D while being turned around the predetermined circumference radially away from the rotation axis 10G of the mixer drum 10. This can render the rotational speed of the shaft 30B relative to the power generation part 30D higher than the rotational speed of the mixer drum 10. As a result, this mixer 10J can generate a larger amount of electric power in the power generation part 30D. Furthermore, the rotor 30F can be made of a material differing from that of the shaft body 30E. In other words, the material of the rotor 30F can be selected according to the material of the contacted part 13, with the result that the rotor 30F can reliably be rotated relative to the contacted part 13.

[0036] Furthermore, the contacted part 13 of the mixer 10J is a cylindrical part formed coaxially with the rotation axis 10G.
Since the rotor 30F is also turned around the predetermined circumference about the rotation axis 10G, the rotor 30F can be always brought into contact with the contacted part 13. As a result, this mixer 10J can always generate electric power in the generator 30 during rotation of the mixer drum 10.

[0037] Furthermore, the generator 30 of this mixer 10J is mounted on the mixer drum 10 so that the rotor 30F is swung radially with respect to the rotation axis 10G of the mixer drum 10. The generator 30 has the spring 30C imparting the elastic force to the rotor 30F in the direction such that the rotor 30F abuts against the contacted part 13. Accordingly, the rotor 30F can be caused to abut against the contacted part 13 while load is applied to the rotor 30F, with the result that the rotor 30F can be restrained from idle rotation relative to the contacted part 13. Furthermore, in the case where the contacted part 13 is the cylindrical part, the rotor 30F can reliably be rotated relative to the contacted part 13 even when the central axis of the contacted part 13 is slightly shifted from the rotation axis 10G
of the mixer drum 10.

[0038] <Second Embodiment>
The mixer truck of a second embodiment differs from that of the first embodiment in the mounting position of the generator 130 on the mixer drum 10, an outer shape of the rotor 130F, and an outer shape of the contacted part 113, as illustrated in Fig.
4. Other construction of the mixer truck of the second embodiment is same as that of the first embodiment. Identical or similar parts are labeled by the same reference symbols as those in the first embodiment, and the detailed description of these parts will be eliminated.

[0039] The shaft 130B includes the shaft body 30E and the rotor 130F. The shaft body 30E is rotatably provided on the generator body 30A and protrudes forward from the front end of the generator body 30A. The rotor 130F is columnar in shape. The rotor 130F
has an outer peripheral surface provided with grooves circumferentially at regular intervals and formed with a spur gear. The rotor 130F has a larger outer diameter than the shaft body 30E. The rotor 130F has a central axis coaxial with a central axis of the shaft body 30E. The distal end of the shaft body 30E
is inserted into the rotor 130F. Thus, the rotor 130F is coupled to the distal end of the shaft body 30E. The shaft body 30E and the rotor 130F both serving as the shaft 130B are rotated together about the central axes relative to the generator body 30A. In other words, the shaft 130B protrudes forward from the front end of the generator body 30A and is rotatable relative to the generator body 30A.

[0040] In the generator 130, the rear ends of the right-left side walls 30G are fixed to the outer surface of the closure part 1OF
of the mixer drum 10, and the shaft 130B extends forward. The shaft 130B of the generator 130 protrudes forward with respect to the mixer drum 10. Since the front end of the generator body 30A is swingably supported by the right-left side walls 30G, the rotor 130F serving as a rotation body of the shaft 30B extending forward from the generator body 30A is swung radially with respect to the rotation axis 10G of the mixer drum 10. Furthermore, the elastic force of the spring 30C is imparted to the rotor 130F
toward the rotation axis 10G of the mixer drum 10.

[0041] The contacted part 113 is coupled to the front end of the support 11. The contacted part 113 is coaxial with the rotation axis 10G of the mixer drum 10 and is a cylindrical part formed around the rotation axis 10G. The contacted part 113 has an outside provided with grooves circumferentially at regular intervals and formed with a spur gear. The elastic force of the spring 30C is imparted to the rotor 130F in a direction such that the outer peripheral surface of the rotor 130F abuts against the outside of the contacted part 113. The contacted part 113 abuts against the rotor 130F while the spur gear provided on the outer peripheral surface of the rotor 130F is in mesh engagement with the spur gear provided on the outer peripheral surface of the contacted part 113. As a result, when the rotor 130F is turned around the outside of the contacted part 113 while rolling on the outside of the contacted part 113, the rotor 130F can be restrained from idle rotation relative to the outside of the contacted part 113.

[0042] In the mixer 10J of the mixer truck of the second embodiment , too, the power generation part 30D is rotated with rotation of the mixer drum 10, whereby the shaft 30B is rotated relative to the power generation part 30D so that electric power is generated in the power generation part 30D. In other words, in this mixer 10J, electric energy can be taken out by making use of the rotative force of the mixer drum 10 which rotates to agitate the ready-mixed concrete. As a result, the mixer 10J can generate electric power by an effective use of the rotative energy of the mixer drum 10 without influences from the ambient environment, such as time of day or weather, and can stably feed the electric power to the slump sensor 16. Furthermore, the mixer 10J does not require a larger mounting area as compared with the case where a solar power generator is mounted, and the generator 130 can easily be mounted on the mixer drum 10. Furthermore, since the electric power is fed from the power generation part 30D mounted on the mixer drum 10 through the power line 14 to the slump sensor 16, the electric power need not be fed from the support 11 side through the power line 14 to the slump sensor 16 provided at the mixer drum 10 side, with the result that electric power can be fed to the slump sensor 16 by a simple circuit.

[0043] Accordingly, the mixer 10J of the mixer truck of the second embodiment can also successfully feed electric power to the slump sensor 16 which is mounted on the mixer drum 10 to be rotated together with the mixer drum 10.

[0044] Furthermore, the power generation part 30D of the mixer 10J is fixed to the outer surface of the mixer drum 10 and rotated on the circumference about the rotation axis 10G of the mixer drum 10. Furthermore, the shaft 130B of the generator 130 is provided with the rotor 130F coupled to the distal end of the shaft 130B. Furthermore, the support 11 has the contacted part 13 with which the rotor 130F is brought into contact while being rotated. Accordingly, the shaft 130B of the generator 130 is rotated relative to the power generation part 30D while being turned around the predetermined circumference radially away from the rotation axis 10G of the mixer drum 10. This can render the rotational speed of the shaft 130B relative to the power generation part 30D higher than the rotational speed of the mixer drum 10. As a result, this mixer 10J can generate a larger amount of electric power in the power generation part 30D. Furthermore, the rotor 130F can be made of a material differing from that of the shaft body 30E. In other words, the material of the rotor 130F can be selected according to the material of the contacted part 13, with the result that the rotor 130F can reliably be rotated relative to the contacted part 113.

[0045] Furthermore, the contacted part 113 of the mixer 10J is a cylindrical part formed coaxially with the rotation axis 10G.
Since the rotor 130F is also turned around the predetermined circumference about the rotation axis 10G, the rotor 130F can be always brought into contact with the contacted part 113. As a result, this mixer 10J can always generate electric power in the generator 130 during rotation of the mixer drum 10.

[0046] Furthermore, the generator 130 of this mixer 10J is mounted on the mixer drum 10 so that the rotor 130F is swung radially with respect to the rotation axis 100 of the mixer drum 10. The generator 130 has the spring 30C imparting the elastic force to the rotor 130F in the direction such that the rotor 130F abuts against the contacted part 113. Accordingly, the rotor 130F can be caused to abut against the contacted part 113 while load is applied to the rotor 130F, with the result that the rotor 130F
can be restrained from idle rotation relative to the contacted part 113. Furthermore, in the case where the contacted part 113 is the cylindrical part, the rotor 130F can reliably be rotated relative to the contacted part 113 even when the central axis of the contacted part 113 is slightly shifted from the rotation axis 10G of the mixer drum 10.

[0047] <Third Embodiment>
The mixer truck of a third embodiment differs from those of the first and second embodiments in the construction of the generator 230, a mounting position of the generator 230 on the mixer drum 10, a laying position of the power line 214, and non-provision of the contacted part, as illustrated in Fig. 5.
Other construction is same as those of the first and second embodiments. Identical or similar parts are labeled by the same reference symbols as those in the first and second embodiments, and the detailed description of these parts will be eliminated.

[0048] In the mixer drum 10, the drive shaft 210B has a front end coupled to the speed reducer 70. The speed reducer 70 includes a first gear 70A and a second gear 70B. The first and second gears 70A and 70B are spur gears. A distal end of the drive shaft 210B
is inserted into the first gear 70A so that the first gear 70A
is coaxial with the drive shaft 210B. The second gear 70B is disposed under the first gear 70A in mesh engagement with the first gear 70A. The second gear 70B has a smaller outer diameter than the first gear 70A. Furthermore, the second gear 70B is coaxially coupled to an output shaft 72 of the hydraulic motor 71.

[0049] The generator 230 includes the generator body 230A serving as the power generation part and the shaft 230B. The generator body 230A is cylindrical in shape. The shaft 2303 is rotatably =

mounted on the generator body 230A. The shaft 230B has a rear part inserted into the generator body 230A and a front part protruding forward from a front end of the generator body 230A.
One end of the power line 214 is connected to a rear end of the generator body 230A.

[0050] The generator 230 is disposed so that the central axis of the shaft 230B is coaxial with the rotation axis 10G of the mixer drum 10 with the side where shaft 230B protrudes being directed frontward. The rear end of the generator body 230A is coupled to the front end of the drive shaft 2103. In other words, the generator body 230A is coupled to the drive shaft 210B of the mixer drum 10 thereby to be rotated about the rotation axis 10G. The power line 214 has one end connected to the rear end of the generator body 230A and the other end connected to the operation part 15 of the slump sensor 16, and is laid through an inside of the drive shaft 210B and then on the outer surface of the mixer drum 10. Thus, the power line 214 electrically connects the generator body 230A and the operation part 15 of the slump sensor 16 serving as the electric device in this mixer truck. In other words, electric power is fed from the generator body 230A serving as the power generation part to the electric device via the power line 214. The generator body 230A is rotated with rotation of the mixer drum 10 in this mixer truck. Then, the generator body 230A is rotated relative to the shaft 2303 with the distal end being fixed to the support 111. Thus, this mixer truck can generate electric power in the generator 230.

[0051] In the mixer 10J of the mixer truck of the third embodiment, too, the generator body 230A serving as the power generation part is rotated with rotation of the mixer drum 10, whereby the shaft 230B is rotated relative to the generator body 230A so that electric power is generated in the generator body 230A. In other words, in this mixer 10J, electric energy can be taken out by making use of the rotative force of the mixer drum 10 which rotates to agitate the ready-mixed concrete. As a result, the generator 230 can generate electric power by an effective use of the rotative energy of the mixer drum 10 without influences from the ambient environment, such as time of day or weather, and can stably feed the electric power can to the slump sensor 16.
Furthermore, the mixer 10J does not require a larger mounting area as compared with the case where a solar power generator is mounted, and the generator 230 can easily be mounted on the mixer drum 10. Furthermore, since the electric power is fed from the generator body 230A mounted on the mixer drum 10 through the power line 214 to the slump sensor 16, the electric power need not be fed from the support 111 side through the power line 214 to the slump sensor 16 provided at the mixer drum 10 side, with the result that electric power can be fed to the slump sensor 16 by a simple circuit.

[0052] Accordingly, the mixer 10J of the mixer truck of the third embodiment can also successfully feed electric power to the slump sensor 16 which is mounted on the mixer drum 10 to be rotated together with the mixer drum 10.

[0053] Furthermore, the mixer drum 10 of the mixer 10J has the drive shaft 210B which is coaxial with the rotation axis 10G of the mixer drum 10. Furthermore, the generator body 230A serving as the power generation part is coupled to the drive shaft 210B

of the mixer drum 10 thereby to be rotated about the rotation axis 10G. Furthermore, the shaft 230B of the generator 230 is fixed to the support 111 and inserted into the generator body 230A coaxially with the rotation axis 10G. As a result, the shaft 230B can reliably be rotated relative to the generator body 230A, with the result that this mixer 10J can reliably generate electric power in the generator body 230A.

[0054] The present invention should not be limited to the first to third embodiments described above with reference to the drawings, but the technical scope of the invention encompasses the following embodiments, for example.
(1) Although the metal wire formed into the coil shape is used as the elastic member to impart the elastic force to the generator body and the shaft in the first embodiment, a leaf spring, synthetic rubber, urethane resin or the like may be used as the elastic member to impart elastic force to the generator body and the shaft.
(2) Although the rotor has the columnar shape and has the front end having a smaller outer diameter than the rear end in the first embodiment, the front end and the rear end may have the same outer diameter or the front end may have a larger outer diameter than the rear end.
(3) Although the outer peripheral surface of the rotor serving as the rotation body abuts against the outside of the contacted part in the first and second embodiments, the elastic force of the spring may be imparted to the generation shaft and the generator body in a direction such that the shaft and the generator body depart from the rotation axis of the mixer drum, so that the outer peripheral surface of the rotor abuts against the inside of the contacted part.
(4) Although the outer peripheral surface of the rotor abuts against the outside of the contacted part in the first and second embodiments, the shaft and the generator body may be disposed on the closure part of the mixer drum in the radial direction of the rotation axis, and the elastic force of the spring may be imparted to the shaft and the generator body in the frontward direction of the mixer drum so that the outer peripheral surface of the rotor abuts against the end surface of the contacted part.
(5) Although the grooves are provided circumferentially in the outside of the contacted part at regular intervals and the spur gear is formed in the second embodiment, a helical gear, a bevel gear or the like may be formed, instead.
(6) Although the spur gears are used as the first and second gears of the reducer in the third embodiment, a helical gear, a bevel gear, a worm gear or the like may be used, instead.
(7) Although the rotative force obtained from the engine serving as the power source is transmitted to the mixer drum in the first embodiment, the power source may not be the engine, a rotative force obtained from an electric motor or the like may be used as the power source.
(8) Although the first to third embodiments are directed to the mixer truck, the embodiments may be directed to the mixer which includes a support which is installed at a work site and on which a mixer drum is rotatably mounted. In this case, the rotative power to rotate the mixer drum may be obtained from an electric motor or the like.

(9) Although one slump sensor is provided in the first to third embodiments, the number of slump sensors may be two or more.
(10) Although the speed reducer includes two gears, that is, the first gear and the second gear in the third embodiment, the number of gears may not be two, but may be three or more.
(11) Although the ready-mixed concrete is agitated by the mixer drum in the first embodiment, various types of powder and granular material, liquid and the like may be agitated or kneaded by the mixer drum.
(12) Although the slump sensor is provided on the outer and inner peripheral surfaces of the mixer drum in the first to third embodiments, the slump sensor may be provided anywhere on the inner and outer surfaces of the mixer drum.
(13) Although one generator is provided on the outer surface of the mixer drum in the first and second embodiments, two or more generators may be provided on the outer surface of the mixer drum.
(14) Although the slump sensor is provided on the mixer drum in the first to third embodiments, another electric device such as a tachometer may be provided, instead of the slump sensor.
Explanation of Reference Symbols

[0055] 10... mixer drum; 10B, 210B._ drive shaft; 10G._ rotation axis; 11, 111 ._ support; 13, 113 contacted part; 14, 214 ._ power line; 16 ... slump sensor (electric device); 30, 130, 230 ._ generator; 305, 130B, 230B _. shaft; 30C ._ spring (elastic member); 30D, 230A ._ power generation part; and 30F, 130F ._ rotor (rotation body).

Claims

1. A mixer comprising:
a support;
a mixer drum supported by the support to be rotatable about a rotation axis;
an electric device mounted on the mixer drum to be rotatable together with the mixer drum;
a generator including a power generation part mounted on the mixer drum to be rotatable together with the mixer drum and a shaft protruding from the power generation part to be rotatable relative to the power generation part, the generator generating electric power to be fed to the electric device when the shaft is rotated relative to the power generation part with rotation of the mixer drum; and a power line connecting the power generation part and the electric device.

2. The mixer according to claim 1, wherein:
the power generation part is fixed to an outer surface of the mixer drum to be rotatable on a circumference about the rotation axis of the mixer drum;
the shaft includes a rotation body coupled to a distal end thereof; and the support has a contacted part with which the rotation body is brought into contact while being rotated.

3. The mixer according to claim 2, wherein the contacted part is a cylindrical part formed to be coaxial with the rotation axis .

4 . The mixer according to claim 3, wherein the generator is mounted on the mixer drum so that the rotation body is swung radially with respect to the rotation axis of the mixer drum, and the generator has an elastic member imparting an elastic force in a direction such that the rotation body abuts against the contacted part .

5. The mixer according to claim 1, wherein:
the mixer drum has a drive shaft provided coaxially with the rotation axis;
the power generation part is coupled to the drive shaft of the mixer drum to be rotatable about the rotation axis; and the shaft is fixed to the support and inserted into the power generation part coaxially with the rotation axis .