Apparatus and method for testing leaf springs

A leaf spring test apparatus, comprising:

• (a) a frame constructed and arranged to support a first end and a second end of a leaf spring, said frame including:
• (i) a base having a first end and a second end;
• (ii) a first support of a predetermined length extending upwardly from said first end of said base for contact with a first end of a leaf spring, said first support being fixedly attached to said first end of said base;
• and
• (iii) a second support of a predetermined length extending upwardly from a support region of said base for contact with a second end of the leaf spring, said second support being a predetermined distance from said first support, said second support being pivotably attached to said base in said support region;
• (b) a force applicator disposed on said frame, said force applicator applying a force to a predetermined area of the leaf spring, said force applicator including a jack and a spring contact plate connected to a piston of said jack, said contact plate having a groove sized and arranged to receive the spring, said force applicator being slidably disposed on said base to maintain the desired contact with the predetermined area of the leaf spring as the leaf spring is compressed and relaxed;
• (c) a force measurement gauge for gauging the amount of force applied to the leaf spring by said force applicator, said force measurement gauge including a load cell electrically connected to a display for reporting the force gauged by said load cell, said load cell being positioned between said spring contact plate and said piston of said jack;
• and
• (d) a distance measurement gauge for gauging movement of the leaf spring upon the application of force by said force applicator, said distance measurement gauge including a digital indicator device and a slide, said digital indicator device cooperating with and sliding with respect to said slide in a measured fashion, said digital indicator device quantifying a position of the leaf spring.

A leaf spring test apparatus, comprising:

• (a) a frame constructed and arranged to support a first end and a second end of a leaf spring, said frame including:
• (i) a base having a first end and a second end;
• (ii) a first support of a predetermined length extending upwardly from said first end of said base for contact with a first end of a leaf spring;
• and
• (iii) a second support of a predetermined length extending upwardly from a support region of said base for contact with a second end of the leaf spring, said second support being an adjustable predetermined distance from said first support, said second support being removably attached to said base at a plurality of locations within said support region;
• (b) a force applicator disposed on said frame, said force applicator applying a force to a predetermined area of the leaf spring, said force applicator including a jack and a spring contact plate connected to a piston of said jack, said contact plate having a groove sized and arranged to receive the spring;
• (c) a force measurement gauge for gauging the amount of force applied to the leaf spring by said force applicator, said force measurement gauge including a load cell electrically connected to a display for reporting the force gauged by said load cell, said load cell being positioned between said spring contact plate and said piston of said jack;
• and
• (d) a distance measurement gauge for gauging movement of the leaf spring upon the application of force by said force applicator, said distance measurement gauge including a digital indicator device and a slide, said digital indicator device cooperating with and sliding with respect to said slide in a measured fashion, said digital indicator device quantifying a position of the leaf spring, said digital indicator device being a magnetic travel indicator, said slide being connected to the leaf spring and said digital indicator device being mounted at a predetermined height.

A method for testing and measuring the spring rate of leaf springs, comprising the steps of:

• (a) providing a leaf spring test apparatus including:
• (i) a frame constructed and arranged to support a leaf spring;
• (ii) a force applicator disposed on the frame, the force applicator applying a force to a predetermined area of the leaf spring to cause a spring displacement, the force applicator including a jack;
• (iii) a force measurement gauge operably positioned and arranged with respect to the force applicator to gauge the amount of force applied to the leaf spring by the force applicator;
• and
• (iv) a distance measurement gauge operably positioned and arranged with respect to the leaf spring to gauge the spring displacement by identifying an actual or representative initial position of the leaf spring occurring prior to the application of the force to the leaf spring and a corresponding actual or representative final position of the leaf spring occurring after the application of the force to the leaf spring;
• (b) installing the leaf spring on the leaf spring test apparatus;
• (c) zeroing the distance measurement gauge of the leaf spring test apparatus;
• (d) pumping the jack on the leaf spring test apparatus to apply a force to the leaf spring and raise the leaf spring a desired distance;
• and
• (e) reading the force measurement gauge to identify the amount of force applied to the leaf spring by the force applicator.

A method for testing and measuring the spring rate of leaf springs, comprising the steps of:

• (a) installing a leaf spring on a leaf spring test apparatus, including the steps of:
• (i) selecting proper bushings for the leaf spring;
• (ii) inserting the bushings into the leaf spring;
• (iii) carefully setting the leaf spring into the groove on the spring contact plate;
• (iv) holding the leaf spring so the surface of the spring that touches the plate is parallel to and is lying flat on the plate;
• (v) inserting bolts through the bushings and the corresponding apertures on the frame to support the spring;
• (vi) tightening the nuts on the bolts;
• and
• (vii) verifying that the leaf spring is lying flat on the spring contact plate;
• (b) zeroing a leaf spring test apparatus, including the steps of
• (i) pumping the jack to apply a force to the leaf spring;
• (ii) lowering the jack by opening a jack valve;
• and
• (iii) zeroing the force measurement gauge and the distance measurement gauge;
• (c) pumping a jack on the leaf spring test apparatus to raise the leaf spring a desired distance;
• and
• (d) reading a force measurement gauge.