from center bearing 28 with reference to fig9 and 13 saddle body 40 is provided with a longitudinal groove 62 a block 63 is slidably mounted in longitudinal groove 62 a pivot pin 64 is fastened in block 63 the plurality of pivotally connected grooved guide straight rail sections 15 are each provided with two tenter clip tracks vis a working side track 66 and a return side track 67 each rail section 15 has a pivotal recess 68 on one end and a pivotal tongue 70 on the opposite end see fig1 and 10 pivotal tongues 70 are adapted to pivotally engage pivot pins 64 and lie in the respective pivotal recess 68 in this manner a plurality of pivotally connected straight or longitudinally grooved guide rail sections 15 provide a left side guide path generally indicated at 72 in fig1 for tenter clips formed into a closed loop circulating tenter chain and a similar right side guide path generally indicated at 73 the diagrammatic view fig3 shows that the guide rail sections 15 while constituting straight sections may constitute straight sections of varying lengths so that in pivoted relationship gaps 5 of varying widths exist between adjacent guide rail sections 15 as will presently appear the shafts 14 and saddles 13 adjust the guide rail sections 15 in divergent and convergent relationship to provide curved paths for the tenter clip chains the two guide paths 72 73 provide.