Soft Shift Valve Applications

Refer to catalog data pages 1.4-11E, 20E, 30E, & 40E.

Some years ago we prepared a sales training outline on the Wandfluh Soft Shift Valve series and delivered it at various Distributor Sales Meetings. We had considerable early success, and soft shift type sales grew at a good rate. Most customers knew of the fact that direct solenoid operated spool valves cause noticeable compressive “shifting shock” when energizing, and decompressive “shifting shock” when de-energizing.  The noise level was hard on machine operating personnel, and caused damage to the production parts, as well as decreasing the working life of many hydraulic components such as hose, fittings, relief valves, and pumps, and in every instance the soft shift valve greatly improved on these problems.  See attached list of successful soft shift valve applications.  All are successful, most are still active applications.

However, when sales growth became stagnant, mostly due to steady improvement and new offerings of proportional valves and companion electronics, our soft shift valve series became memory to many.  As we have benefited from the growth of proportional valves and electronics, this has not been a loss; however, we continue to see or hear about applications that can benefit by using soft shift valves, and they are often the proper choice over a more expensive proportional directional control system.  A good application, is the need to smoothly reduce shifting shock in the start- -stop- and reverse modes, when actuator profiling and variable flow rates or pressure are not critical control requirements.  Due to the Wandfluh 5 chambered body and 4 tapered spool lands design, our standard soft shift valves do a good job of reducing the shifting shock in both directions at a sizeable price reduction when compared  to an electronic proportional valve control system.  The soft shift spool system is easier to install, run-in, and service, and can easily be added to an existing direct solenoid operated system by merely replacing the standard sub-plate mounted valve with the soft-shift version.  Mounting patterns, and subplates remain the same, solenoids, and other system components remain the same.      

A.   In-Plant Production Machinery and Processes
1.  Aluminum and Brass Extrusion & Rolling Machines – noise reduction, shock      reduction, improve production quality, decrease components repair costs.

2. High Speed Small Part Plastic Molding Presses – noise reduction, shock reduction, (keeps machine operators from quitting due to noise levels) improve production quality, increase hydraulic components life.

3.Platform Grinding Machines – shifting shock reduction, improve grinding quality.

4.Plastic Pipe Welding Machine – reduce tank line decompression shock that was causing heat exchanger to fail prematurely, relief valve to wear quickly.

5.Hydraulic Hose/Fitting Swaging Machines, Staking Presses, Bearing Presses —  reduce decompression shock when cylinder pressure released, reduce shock noise. 

B.  Test Benches and fixtures.

1.    Hydraulic Components Test Benches – reduce noise, reduce shock, protest new test specimens, gauges, and other read outs.

2.    Specially designed fixtures for specific components to be tested.

3.    Hi-Speed Rotary Actuator control on Wood Sander.

C.  On site, Heavy Duty Trash Grinding and Crushing Machine.  Reduce shock and noise, improve hydraulic and structure cycle life.

D. High Cycle Press and Extrusion Machines – noise reduction, vibration reduction, improve part quality.  Often a feed and ejection function is added and also needs dampening

E.  Mobile Equipment

1.  Off – Highway heavy duty fork lift. Used as a deceleration valve to smooth cylinder       start- start  when loading-unloading’  4 way, 2 position, double solenoid models both NG6 and NG10 sizes

2.   Paving Machine. Cylinder driven screed moves back and forth across  newly laid asbestos, eliminates shock, smooths surface.

3.   Pleasure Boat Transporter.  Soft shifts positioning and clamping cylinders, eliminates  shock that could damage sensitive instruments, etc.

4.   Mobile Hydraulic Crane.  Soft shift valve controls hydraulic cylinder/or motor that rotates (swings) boom left or right.  Smooth start-stop-rotation  required, especially on man-in-bucket cranes.

F.  Rudder Control, marine steering systems.   Soft shift valve controls hydraulic cylinders in  response to bridge or automatic compass signals

G..  Remote  Control , on-off, of material conveyor..  Stop or start shift must be smooth or mat’l may be jolted off conveyor belt.

Ed V. Askey