Manufacturing company Ingersoll Rand — whose product line includes Club Car golf carts, Thermo King refrigerators and Trane air conditioners — is struggling to fill nearly 1,000 open positions, some of which pay more than $100,000, the National Association of Manufacturers reported in its Shopfloor blog. North Carolina-based Ingersoll Rand’s story is another reminder of the uphill climb many manufacturers are experiencing as they grow and seek out a skilled workforce, the association said.