Cleaning device for a vehicular lamp

1. A cleaning device for a vehicular lamp comprising:

a piston provided at a distal end thereof with a spray nozzle that sprays a cleaning fluid and a nozzle cover that forwardly covers the spray nozzle, and

a cylinder that drives the piston to extend and retract with respect to an opening formed in a vehicle body; wherein:

said nozzle cover has a shaft receiving portion with a substantially cylindrical shape that extends from a rear surface of said nozzle cover and an engagement hole which is provided at a position away from the shaft receiving portion;

said piston has at a distal end thereof an engagement shaft portion that projects forward and is to fit with the shaft receiving portion of said nozzle cover and an engagement tab that is to engage with the engagement hole of said nozzle cover;

by moving said nozzle cover toward the distal end of said piston, the engagement shaft portion of said piston is brought to fit with the shaft receiving portion of said nozzle cover and the engagement tab of said piston is brought to engage with the engagement hole of said nozzle cover, so that the nozzle cover is attached to the distal end of the piston;

said nozzle cover has two engagement plate portions that extend in a direction substantially opposite from the shaft receiving portion of said nozzle cover, wherein

the engagement plate portions are formed in a plate shape,

a plane direction of the engagement plate portions substantially faces along an axial direction of said piston, and

the engagement plate portions are formed with said engagement holes; and

said piston has two supporting portions that extend in a direction substantially opposite from the engagement shaft portion of said piston, wherein

the supporting portions are formed in a plate shape,

a plane direction of the engagement plate portions substantially faces along the plane direction of the engagement plate portions of said nozzle cover, and

the supporting portions are respectively provided with said engagement tabs that project from surfaces that face the engagement plate portions of said nozzle cover, the engagement tab having:

an inclined surface that faces said nozzle cover and whose projection height gradually increases in a direction away from said nozzle cover, and

an engagement surface that is a surface opposite from the inclined surface and is substantially perpendicular with respect to an axial direction of said piston.

2. The cleaning device for a vehicular lamp according to claim 1 , wherein

in said piston, the engagement shaft portion and the supporting portions are formed continuously by gently concave-curved surfaces.

3. The cleaning device for a vehicular lamp according to claim 1 , wherein

said nozzle cover is provided with reinforcement ribs that are of a plate shape and extend from a rear surface of said nozzle cover and;

end portions of the engage ment plate portions that project out of the shaft recieving portion of the nozzle coverare connected to the reinforcement ribs.

4. A cleaning device for a vehicular lamp comprising:

a piston provided at a distal end thereof with a spray nozzle that sprays a cleaning fluid and a nozzle cover that forwardly covers the spray nozzle, and

a cylinder that drives the piston to extend and retract with respect to an opening formed in a vehicle body; wherein:

said nozzle cover has a shaft receiving nortion with a substantially cylindrical shape that extends from a rear surface of said nozzle cover and an engagement hole which is provided at a position away from the shaft receiving portion;

said piston has at a distal end thereof an engagement shaft vortion that projects forward and is to fit with the shaft receiving portion of said nozzle cover and an engagement tab that is to engage with the engagement hole of said nozzle cover;

by moving said nozzle cover toward the distal end of said piston, the engagement shaft portion, of said piston is brought to fit with the shaft receiving portion of said nozzle cover and the engagement tab of said piston is brouaht to eneaze with the engagement hole of said nozzle cover, so that the nozzle cover is attached to the distal end of the piston;

the engagement shaft portion of said piston is provided on an outer peripheral surface thereof with a retaining ridge that extends in an axial direction of the engagement shaft portion;

the shaft receiving portion of said nozzle cover is formed with an engagement notch that extends in an axial direction of the shaft receiving portion and opens toward a rear end of the shaft receiving portion; and

the retaining ridge of said piston engages with the engagement notch of said nozzle cover.

5. The cleaning device for a vehicular lamp according to claim 1 , wherein

said piston is provided with a detachable holder that is formed with the engagement shaft portion and the engagement tab.

6. The cleaning device for a vehicular lamp according to claim 3 , wherein

the engagement shaft portion of said piston is provided on an outer peripheral surface thereof with a retaining ridge that extends in an axial direction of the engagement shaft portion;

the shaft receiving portion of said nozzle cover is formed with an engagement notch that extends in an axial direction of the shaft receiving portion and opens toward a rear end of the shaft receiving portion; and the retaining ridge of said piston engages with the engagement notch of said nozzle cover.