The task of such linking, looping or hemming machines is in particular to cleanly and durably link or loop the edges of carpets or the like in the form of a roll product and which are cut to the use size. The aim of the invention is that despite the relatively high capacity of the machine, it can be easily handled and can also be used in a mobile manner, because in particular when looping very large surfaces the space required for moving the complete material portion passed the machine would be excessive.
The machine according to the invention has a drive, a sewing mechanism with means for conveying the material relative to the sewing mechanism, a needle mechanism and a loop forming mechanism, as well as a thread feed to the needle and loop forming mechanisms.
According to one feature of the invention the sewing mechanism preferably constructed for forming a two-thread overlock or overcast seam has a retaining gripper, which holds back a thread loop during the formation of an overlock or overcast loop. It preferably engages close to the needle movement path from below into the thread coming out of a yarn gripper.
U.S. Pat. No. 4,062,307 discloses a sewing machine producing a single-thread overcast seam. It uses a yarn gripper gripping in a loop the thread passed through the material with the needle and is passed around the edge for the next needle perforation in said loop. This machine operates in a completely satisfactory manner and can also loop thick carpets with a limited constructional size and high capacity. However, relatively large thread lengths must be drawn at high speed through the needle hole, because the entire thread supply or feed takes place from above via the needle. As the thread for looping normally consists of a relatively slightly turned thick and bulky yarn, in the case of floor coverings with a very rigid and firm back working with great care is necessary, so that the yarn does not unravel and tear during the drawing through the hole.