Center Of Percussion

[mewhg]

Perhaps someone has more experience in this area than myself.

I am designing a mechanism "hammer" to be cut out of 3/16" plate that will be spring powered to swing through an arc of about 70 degrees. It will strike a rod with a 3/8 radius on the end of the rod.

I need to minimize the reaction at the pivot point and make the strike as fast and as smooth as possible.

I want to match the center of strike with the Center of Percussion which is straightforward enough to calculate and design for. However, the hammer is "L" shaped and a line through the Center of Rotation/Center of Gravity/Center of Percussion is not perpendicular to the axis of the 3/8" rod.

Does the non-perpendiculary matter in designing for a "sweet spot"? Everything I have read on the COP talks about hammers or baseball bats which have a uniform centerline that coincides with the COG and COP.

Thanks in advance

Bill

 

[ccw]

Hi Giessele,
I think you are correct to stick with the center of percussion. However, with an irregular shape the "sweet spot" may be out in space (off the object). You may have to construct a strike point. If the angle of contact to the surface is other than perpendicular, the reaction may introduce radial loads into or away from the center of rotation.