Jounce Tester

The Jounce Tester is intended to evaluate either seat components, or a complete seating system. The evaluation criteria are usually visual.  These include wear patterns, or general durability of the seat covering material, the foam, and the support structure underneath.

The upper jounce loading mechanism includes an appropriate body form and loose weights that can be added as necessary. This upper assembly is guided through eight ball bearings and four lightweight aluminum parallel arms, back to the main support frame. The entire set-up is then height adjustable to maintain horizontal parallelism of the arms. There is also an overhead 500-pound (227kg) capacity cantilever type crane to suspend the loading mechanism while test samples are installed or removed.

It is important to notice that this type of mechanical design loads the test sample with the correct amount of body weight without inducing excessive inertia loads, like some other test machines do. These high inertia loads on some competitive equipment increase the severity of the test and may cause some borderline samples to fail when they really do not.

The lower jounce table is servo-hydraulic driven and operated with a P.C. based control system. The vertical movement is sinusoidal and programmable for both frequency and acceleration. For any given acceleration, amplitude decreases as frequency increases. The system is also capable of frequency "sweeps" and other test-dictated sequences. The actual software is custom written by Schap Specialty Machine, Inc. in Visual Basic, which operates in a Windows operating environment.

Generally, this destructive test system is rather simple to set-up and operate. Technicians that are P.C. literate will have no trouble quickly learning how to operate the machine and the software.

Jounce Table

This is a stand alone item that can be rented alone or with an hydraulic power pack and upper frame. The jounce table can produce cyclic (sine wave) outputs ranging from 0.5 Hz to 20 Hz with amplitudes from 1 mm to 100 mm. The table comes with a roll-around control cart, is PC controlled, and has software for seat testing (or any other item needing cyclic or vibration testing) with jounce, as well as resonance, and damping. The table can be operated in displacement mode following displacement of the table or the upper (saddle). The table can also be operated in acceleration mode where the amplitude of the jounce is varied to hold a constant acceleration either on the table or the upper (saddle). Acceleration can be controlled from 0.1 G to 1.5 G depending on test frequency.

Burke-Porter Style Jounce Upper

This counter-weighted upper is the jounce style originally produced by Burke-Porter. The unit includes two standard butt forms and hydraulic control of squirm for standard automotive seat testing as well as intermittent lifting during the test. Loading is adjusted by addition of weights to each butt form support. This unit can be rented alone or in combination with our jounce table and hydraulic power pack to obtain a complete testing unit.

Japanese Style Jounce Upper

This jounce upper is the Japanese, non-counter-weighted style. Loading is accomplished by adding weights to each standard butt form. The butt forms can be raised with the chain fall provided. The chain fall also allows a butt form to be dropped onto a seat which, when used with our jounce table, can calculate the damping factor of the seat. Independent hydraulic squirm is also provided on this station when used in conjunction with an appropriately sized hydraulic power pack.

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