Subsidiaries of 3M and Caterpillar have both backed smart industrial hardhat developer Guardhat, boosting its overall funding to $24m.

US-based smart hardhat manufacturer Guardhat has closed a $20m series A round featuring 3M Ventures and Caterpillar Venture Capital, respective subsidiaries of manufacturing conglomerate 3M and construction equipment maker Caterpillar.

Venture capital firm RTP Ventures led the round, which also featured venture debt provider Silicon Valley Bank, VC firm Revolution’s Rise of the Rest Seed Fund and investment firm Detroit Venture Partners (DVP).

Founded in 2014, Guardhat has devised a smart hardhat for industrial sites that enables supervisors to monitor the…