Hi.
I´m trying to put my assembly into motion but struggling with figuring out the appropriate mates. The drive arm is connected to a motor turning it anticlockwise

(solidworks files of the assembly are attached) and the violet pin should always stay in the groove of the shaft. I was thinking about doing it by a tangent mate between the pin and the inside of the groove but as the groove is curved, there are several inside faces, which causes a problem.
Does anyone have any idea how to solve this?
Thanks a lot for any help.