Does anyone know the significance of an HAC clock's lamp and oil trade mark? ( as opposed to the usual double crossed arrows... )
My old mantle/ alarm clock movement has this particular mark stamped on it. I wonder whether someone can help me figure out the approximate year of production. Any info is greatly appreciated.
Thank you.

The Bulletin article* on German Trademarks shows 4 different trademarks for HAC. It gives same dates and locations for all four. No explanation of why there are different ones.

*Whole Number 187, page 156

Thank you so much, Tom , for your input. I appreciated it! How strange that is...four different trade marks with same dates... It seems that you see more arrow mark for HAC than others.

Here are the four trademarks attributed to HAC.