Claims
- 1. Apparatus for stretching web material by use of tentering clips and providing a uniform distribution of transverse stretching forces comprising a frame, a plurality of cross members secured to said frame, a plurality of bearings fastened to each cross member, a plurality of shafts, one for each cross member, each shaft having a right hand thread and a left hand thread, means rotatably mounting said shafts in said plurality of bearings, a plurality of saddles, two for each cross member, means slidably mounting said saddles to said cross members, a plurality of nuts, one secured in each saddle, one nut of one saddle of an associated shaft connected to a right hand thread, alternately, another nut of the other saddle of the shaft connected to a left hand thread, whereby rotation of the shaft in one direction draws the saddles toward each other and rotation of the shaft in an opposite direction separates said saddles , a plurality of blocks, one for each saddle, means slidably mounting a block in each saddle, a plurality of pivot pins, one fastened in each block, a plurality of grooved guide straight rail sections having a straight tenter clip engaging faces, pivotally mounted to said saddles, with the end of one rail being pivotally mounted to the end of an adjacent rail through said pivot pins, thereby to provide two pivotally connected adjacent grooved guide straight rail sections with a gap therebetween, said plurality of grooved guide straight rail sections forming two closed loop paths to accommodate, respectively, two closed loop tentering chains, said shafts providing incremental adjustment between pairs of rails controlled by the same shaft and incremental adjustments between adjacent rails, that improvement in which means between the ends of adjacent grooved guide straight rail sections provide a gap crossing mechanisms, said means yielding on an arc, having a radius with the center located in the center of the pivot pin, upon relative pivotal movement between adjacent grooved guide straight rail sections, said means providing a smooth arcuate connection between the straight tenter clip engaging faces having various degrees of diverging and converging relationship with respect to one another, said means between the ends of adjacent grooved guide straight rail sections comprises a bar consisting of two compatible half sections which slidably engage, each half section comprising a head, a sliding surface terminating at a shoulder formed in said head, a tenter clip track surface on one side of said sliding surface and a plurality of slits in the surface on the side opposite said tenter clip track surface, a front chamber and a rear chamber provided, respectively, in opposite ends of each grooved guide straight rail section, said bar located between opposite ends of adjacent grooved guide straight rail sections, one head located in a front chamber and the other head located in a rear chamber with said tenter clip track surface forming a smooth connection between the tenter clip engaging surfaces of the respective adjacent pivotally connected grooved guide straight rail sections, and means fastening the respectively heads in the respective chambers, whereby relative pivotal movement between adjacent grooved guide straight rail sections arcuately bends said bar across said plurality of slits.
BACKGROUND OF THE INVENTION
This application is a division of Patent Application Ser. No 703,577 filed July 8, 1976.
US Referenced Citations (6)
Foreign Referenced Citations (2)
Number |
Date |
Country |
694,192 |
Jul 1940 |
DT |
1,201,123 |
Aug 1970 |
UK |
Divisions (1)
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Number |
Date |
Country |
Parent |
703577 |
Jul 1976 |
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