Apparatus for forming prestressed concrete sheets

Claim 1

IN A WIRE TENSIONING APPARATUS FOR THE FORMING OF PRESTRESSED CONCRETE SHEETS, A TENSOR ARM PIVOTALLY MOUNTED FOR MOVEMENT IN A VERTICAL PLANE ABOUT ONE END THEREOF BETWEEN A FIRST POSITION WHEREIN THE OTHER END OF SAID ARM IS DISPOSED SUBSTANTIALLY ABOVE SAID ONE END AND A SECOND POSITION WHEREIN SAID OTHER END IS DISPOSED A PREDETERMINED DISTANCE BELOW AND BEHIND SAID ONE END, UPSTANDING STATIONARY ABUTMENT MEANS ENGAGED BY SAID ONE END OF SAID ARM FOR PREVENTING DISPLACEMENT OF THE PIVOT AXIS OF SAID ARM, SAID OTHER END OF SAID TENSOR ARM BEING PROVIDED WITH MEANS FOR RETAINING LOOPS OF WIRE WHILE AT THE SAME TIME PERMITTING LIMITED MOVEMENT OF THE WIRE OF SAID LOOPS ALONG THE WIRE''S LONGITUDINAL AXIS, AND A DRIVING MECHANISM OPERATIVELY ASSOCIATED WITH SAID TENSOR ARM FOR GRADUALLY PIVOTING THE SAME BETWEEN SAID FIRST AND SECOND POSITIONS AND FOR PREVENTING SUDDEN MOVEMENT OF SAID OTHER END OF SAID TENSOR ARM IN RESPONSE TO ABRUPT CHANGES IN THE FORCES ACTING THEREON.