Methods of manufacturing a resilient rail clip

Abstract

A method of manufacturing a resilient rail clip comprises bending a rod, made of metal having a hardness value falling within a known hardness value range, into a predetermined shape and then subjecting the bent rod to a cold setting process in order to induce in the bent rod a predetermined amount of permanent set (S). One cold setting process comprises applying a first load (F 0 ) to part of the bent rod so as to cause a first amount of deflection of that part of the bent rod, which first load (F 0 ) is a predetermined load having a value equal to or greater than that required to reach the yield point of metal having the highest hardness value in the said hardness value range, measuring the first amount of deflection (d X ) of the said part of the bent rod achieved by applying the predetermined first load (F 0 ), determining, on the basis of the measured deflection amount (d X ), either (i) a second load (F 0 +ΔF X ), which, when applied to the said part of the bent rod, will cause the bent rod to acquire the predetermined amount of permanent set (S), or (ii) a second amount of deflection (d X +Δd X ) of the said part of the bent rod required in order to bring about in the bent rod the predetermined amount of permanent set (S), and applying the second load (F 0 +ΔF X ) to the said part of the bent rod or deflecting the said part of the bent rod by the determined second amount of deflection (d X +Δd X ). An alternative cold setting process comprises deflecting part of the bent rod by a predetermined first amount (d 0 ) by applying a first load (F X ) having a value equal to or greater than that required to reach the yield point of metal having the highest hardness value in the said hardness value range, measuring the amount of the first load (F X ) required to achieve the predetermined first amount of deflection (d 0 ), determining, on the basis of the measured load, either (i) a second deflection amount (d 0 +Δd X ) required in order to bring about in the bent rod the predetermined amount of permanent set (S), or (ii) a second load (F X +ΔF X ), which, when applied to the said part of the bent rod, will cause the bent rod to acquire the predetermined amount of permanent set (S), and deflecting the said part of the bent rod by the determined second deflection amount (d 0 +Δd X ) or applying the determined second load (F X +ΔF X ) to the said part of the bent rod.

1 . A method of manufacturing a resilient rail clip comprising bending a rod, made of metal having a hardness value falling within a known hardness value range, into a predetermined shape and then subjecting the bent rod to a cold setting process in order to induce in the bent rod a predetermined amount of permanent set, wherein the cold setting process comprises:
 applying a first load to part of the bent rod so as to cause a first amount of deflection of that part of the bent rod, which first load is a predetermined load having a value equal to or greater than that required to reach the yield point of metal having the highest hardness value in the said hardness value range;   measuring the first amount of deflection of the said part of the bent rod achieved by applying the predetermined first load;   determining, on the basis of the measured deflection amount, either (i) a second load, which, when applied to the said part of the bent rod, will cause the bent rod to acquire the predetermined amount of permanent set, or (ii) a second amount of deflection of the said part of the bent rod required in order to bring about in the bent rod the predetermined amount of permanent set; and   applying the determined second load to the said part of the bent rod or deflecting the said part of the bent rod by the determined second amount of deflection.   
     
     
         2 . A method of manufacturing a resilient rail clip comprising bending a rod, made of metal having a hardness value falling within a known hardness value range, into a predetermined shape and then subjecting the bent rod to a cold setting process in order to induce in the bent rod a predetermined amount of permanent set, wherein the cold setting process comprises:
 deflecting part of the bent rod by a predetermined first amount by applying a first load having a value equal to or greater than that required to reach the yield point of metal having the highest hardness value in the said hardness value range;   measuring the amount of the first load required to achieve the predetermined first amount of deflection;   determining, on the basis of the measured first load, either (i) a second deflection amount required in order to bring about in the bent rod the predetermined amount of permanent set, or (ii) a second load, which, when applied to the said part of the bent rod, will cause the bent rod to acquire the predetermined amount of permanent set; and   deflecting the said part of the bent rod by the determined second deflection amount or applying the determined second load to the said part of the bent rod.