Multiple Cylinder Pull Tester

Pull Testers are intended to satisfy the requirements of FMVSS 207, 208, 210 & 225 along with ECU 17 & 19.  They are also capable of testing other components not included in those specifications.  Any number of cylinders from 1 to 9 (and more) are available and up to 10,000 pounds (4536kg) capacity per cylinder.  These machines also include a separate, floor standing, P.C. based Control & Data Acquisition system.

The basic machine is built with a one inch thick, ground steel, work bench height, pull surface that includes a 4" array of ½" – 13 holes tapped through it.  Considerable additional structural steel under this surface minimizes any frame deflection, which could become an issue when reviewing cylinder displacement data.  This test sample mounting area is wide enough to attach a three-place automotive style bench seat. All other hydraulic systems are mounted under the table along with extra space for fixture storage.  The cylinders are arranged on three cross beams and can easily be slid sideways by hand. Since all three cross beam assemblies are the same, cylinders can be relocated to different beams at any time.  Each beam can be individually raised and lowered with a separate lift handle at the bottom.  All cylinders are mid-trunnion mounted and balanced such that they are neutral with the rod at mid-stroke and the load cell attached.  Some cylinders are additionally gimbal mounted to provide swivel in both axis, as need with seat belt pulls.

Cylinder capacities can be up to 10,000 pounds (4536kg) per cylinder, but it is advised to not request them much larger than is necessary. This improves test accuracy and dynamic response for the majority of customer requirements.  Each cylinder includes an internal displacement transducer as opposed to a separate transducer of any type.  This compensates for any possible cylinder rotation upon test sample twist during deformation.  Each cylinder also includes a dedicated accumulator and anti-backflow arrangement to provide momentary hydraulic isolation upon rapid movement of any of the other cylinders.  This concept minimizes both recovery time of the effected cylinder and any data acquisition "cross-talk" on the remaining cylinders when a rapid displacement is experienced. Each cylinder is operated by it's own proportional valve and closed loop PID controller for maximum accuracy and flexibility.

A separate P.C. based Control and Data Acquisition System is included and housed within a separate floor standing console.  The software is custom programmed by Schap Specialty Machine, Inc. in Visual Basic and operates in a standard Windows environment.  Loading profiles can be individually programmed for each cylinder.  Data acquisition of both load and position is automatically plotted for each cylinder with a wide selection of user and display options.  The final graphical result can then be printed on the plain paper color ink jet printer, which is also housed within the console.  This test data can also be saved or downloaded to any other suitable P.C. type format.

Generally, this destructive test system is rather simple to both set-up and operate.  Technicians that are P.C. literate will not have trouble learning how to operate the software

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