Chute turning restriction mechanism

1. A chute turning restriction mechanism that restricts turning of a chute of a mixer truck, comprising:

a rotary shaft on which the chute is disposed and which is provided to be capable of rotating relative to a vehicle body of the mixer truck;

a bracket that is provided on the vehicle body, and includes an insertion hole into which the rotary shaft is inserted and a cutaway portion formed by cutting away a part of the insertion hole;

an inner diameter adjustment shaft provided across the cutaway portion to be capable of adjusting an inner diameter of the insertion hole, and configured to restrict rotation of the rotary shaft by reducing the inner diameter of the insertion hole;

a rotary body that is provided to rotate together with the rotary shaft and includes an engagement groove; and

a lock lever that is provided to be capable of rotating about the inner diameter adjustment shaft, and that restricts the rotation of the rotary shaft by engaging with the engagement groove.

2. The chute turning restriction mechanism as defined in claim 1 , wherein the inner diameter adjustment shaft comprises a base end shaft, a small diameter shaft having a smaller diameter than the base end shaft, and a screw portion formed on a tip end of the small diameter shaft,

the bracket is a member including the cutaway portion, which is provided between respective ends of the bracket in a circumferential direction of the insertion hole,

a through hole through which only the small diameter shaft passes is formed in one end of the bracket,

a screw hole into which the screw portion is screwed is formed in another end of the bracket, and

the inner diameter of the insertion hole is modified by rotating the inner diameter adjustment shaft to adjust an interval of the cutaway portion between the respective ends of the bracket.

3. The chute turning restriction mechanism as defined in claim 1 , wherein the engagement groove engages with the lock lever only when the chute is positioned in a storage position.

4. The chute turning restriction mechanism as defined in claim 1 , wherein the rotary body includes a plate-shaped member that projects in a radial direction of the rotary shaft,

the engagement groove is formed to penetrate an outer edge position of the plate-shaped member,

the lock lever is configured such that a lever upper end portion is positioned in the cutaway portion and a lever lower end portion rotates between a first position and a second position below the first position, and

when the lever lower end portion is positioned in the first position, the lever upper end portion is positioned below the rotary body, and when the lever lower end portion is positioned in the second position, the lever upper end portion is inserted into the engagement groove so as to be engaged therewith.

5. The chute turning restriction mechanism as defined in claim 4 , wherein the lock lever is configured to rotate from the first position to the second position under its own weight.

6. The chute turning restriction mechanism as defined in claim 1 , wherein a carrying portion carrying the bracket is formed on the vehicle body, and

a guide groove for guiding a rotation operation of the lock lever is formed in the carrying portion.

7. The chute turning restriction mechanism as defined in claim 1 , wherein a pin is formed on the vehicle body so as to project from the vehicle body, and

the bracket includes a coupling hole for coupling the bracket to the pin.

8. The chute turning restriction mechanism as defined in claim 7 , wherein the rotary body comprises:

a first contact portion that defines a first turning limit position of the chute by contacting an outer peripheral surface of the pin projecting from the coupling hole when the rotary shaft rotates in one direction; and

a second contact portion that defines a second turning limit position of the chute by contacting the outer peripheral surface of the pin projecting from the coupling hole when the rotary shaft rotates in an opposite direction.