We read, apparently based on the Tosefta, that a worker cannot be a shaliach tzibbur nor can he "duchan" because as Rashi says this involves too much of a break from working. But why is there a greater break since the worker is allowed to daven? Does he mean he has to daven without a minyan?
It is clear from the Mishnah Berurah (OC 110:12) that this is how the Achronim learned the Gemara. A normal worker may not go to Daven with a Minyan. If there is a Minyan with him at his place of work, then he may not be the Chazan, because doing so takes more time away from his work (see Rashi, DH Aval Ein Yordin).
Kollel Iyun Hadaf