Work Supports / Double Acting
Frequently Asked Questions, Operation
When do I need to use Double-Acting Work Supports as opposed to other work supports? You will want to use Double Acting Work Supports whenever your application requires positive retraction of the work support plunger such as in automatic/unattended applications. The support plunger is retracted when hydraulic pressure reduction pulls back the shuttle cylinder. You will not be relying on a mechanical spring to return the plunger to its initial starting position. Consider Double Acting Work Supports whenever your application requires extremely tight tolerances. When pressurized, the Double Acting Work Support sets the industry standard for minimizing elastic deformation and maximizing uniformity in clamping surface stability. You will want to use Double Acting Work Supports in applications where the single acting fluid advanced work support might kick your part out of position when unclamp occurs. The hydraulic pressure on the sleeve gripping the plunger is maintained until the double-acting positioning piston retracts. An internal check valve opens to release the pressure on the sleeve. The plunger is released only after it has been pulled back from the workpiece. This “shuttle” action prevents “workpiece ejection” that might be experienced with single acting fluid advanced Work Supports.
I understand that this work support has two (2) strokes, a shuttle stroke and a work support stroke. Do these strokes add one upon the other resulting in a total stroke of 0.875 inches? No, the support plunger stroke is contained within the piston shuttle stroke. Because the work support plunger is spring advanced, it is extended while the sleeve is unlocked. The shuttle strokes forward causing the extended plunger to contact the part and compress the spring. Finally, the internal sleeve locks the plunger in place. Does the shuttle extend and stroke the full 0.50 inches every time? Yes, the advance shuttle will travel a full stroke every time. However, it stops on an internal component allowing the inside sequencing to lock the work support plunger. Where do I position my part so it is in the work support plunger “working zone”? Position the part in the middle of the plunger stroke. The catalog chart lists a dimension that represents the fully extended length. For best performance, position your part at the fully extended shuttle stroke minus half of the plunger stroke.
I thought it was wrong to clamp over a column of fluid! How can I clamp over a work support that is inside a cylinder supported by hydraulic fluid? While it is not the best option to clamp over a column of fluid, neither is it always wrong. Certain considerations must be addressed and adhered to when this is done. In this application, the work support is supported by the advance cylinder which is held firmly against a shoulder inside the body. This positioning is maintained by a 3:1 ratio of seating force verses the support force of the work support plunger. This advance/support ratio has shown to be the most stable combination and has the least elastic deformation compared to other units on the market.
B-21
2750 lb TOP FLANGE DOUBLE ACTING WORK SUPPORT CYCLE
0.125” contact clearance from part in retracted position
WORK PIECE
0.375” PLUNGER WORKING ZONE
0.500” Shuttle stroke range
2.625”
2.250”
1.250”
SHUTTLE RELEASES PLUNGER NEVER EJECTING A PART!
SHUTTLE RETURNS WITH PLUNGER LOCKED
PLUNGER CONTACTS PART TUFF™GRIP LOCKS
SHUTTLE ADVANCES PLUNGER
© Vektek, January 2023
800-992-0236
www.vektek.com
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