Vektek makes a full range of interfaces (decouplers) and accessories that operate between a stationary pump and the palletized fixtures in CNC machining center operations to provide safe, efficient and fast connections.
We are frequently asked questions which are common to both novice and experienced users about pallet and tombstone clamping systems. The answers to the following questions may help users better understand palletized hydraulic systems. Contact Vektek for assistance in determining if you should use a decoupled fixture or leave the fixture connected to the pump.
What is a pallet decoupler and what is its purpose within a clamping system?
A pallet decoupler is a device which serves as the interface between the stationary pump and the moving pallet, and is the point where the hose(s) from the pump is connected and disconnected from the pallet. The decoupler "rides along" on the pallet and is the regulator of pressurized hydraulic fluid for the clamping circuit while it is disconnected from the pump.
A decoupler must contain a shutoff valve to trap pressurized fluid from the pump within the clamping circuit and allow the hose(s) to be disconnected from the pallet. A decoupler must also contain; a coupler(s) for connecting the hose(s), filter screens to minimize the amount of contamination that enters the pallet hydraulic circuit and an accumulator to store pressurized hydraulic fluid for pressure maintenance to the clamping circuit while the pallet is disconnected from the pump. A decoupler also includes ports for connection of the pallet hydraulic circuit and may include a pressure gauge and an over-pressure relief valve.
What are the basic types of pallet decouplers?
We divide pallet decouplers into two basic types based on whether the shutoff valve operates automatically or manually. In Manual Shutoff Valve Decouplers the operator manually closes the shutoff valve to trap pressure on the pallet (to keep the parts clamped) and manually opens it to release pressure from the pallet (unclamp the parts). With a Manual Shutoff Valve Decoupler the operator must also control the pump to pressurize the pallet and release pressure from the hose(s) for disconnection. For ease of operation, most Manual Shutoff Valve Decouplers are used with single acting clamp systems or circuits.
In an Automatic Shutoff Valve Decoupler the shutoff valve is actuated by Clamp and Unclamp pressures from the pump and the operator needs to control only the pump. Automatic Shutoff Valve Decouplers are used with both single and double acting circuits with equal ease.
What is the difference between a pallet decoupler and a tombstone top plate?
A tombstone top plate is an expanded type of Manual Shutoff Valve Decoupler. A decoupler has one shutoff valve to control one pallet circuit. A tombstone top plate has multiple shutoff valves to provide separate control of each single acting circuit (face) and a common accumulator to keep all circuits pressurized when the tombstone is disconnected from the pump. Tombstones that require double acting clamping circuits must use one Automatic Shutoff Valve Decoupler per face or circuit.
If I don't have enough space for a decoupler (or top plate) with its accumulator, can I use just a shutoff valve and a disconnect coupler?
Absolutely not, every hydraulic clamping pallet and tombstone must have an accumulator to be safe! We offer decouplers with integral accumulators to minimize their size, and decouplers and top plates that allow the accumulator to be located to a place on the pallet or tombstone that has more space. In addition, we can provide all the individual components required to implement a distributed decoupling system to safely conform to your space limits.
What type of pump do I need to operate decouplers and Tombstone Top Plates?
Manual Shutoff Valve Decouplers and Tombstone Top Plates require an on-demand pump that includes a 2-Position 3-Port directional control valve and a mating coupler with suitable hose.
Automatic Shut off Valve Decouplers require an on-demand pump that includes a 3-Position 4-Port, pressure blocked center directional control valve, and a decoupler Operating Handle with suitable hoses.
Pumps for palletized fixtures must be configured to de-pressurize the hose(s) for connection and disconnection. See Basic Pump recommendations for each type of decoupler. Pumps can also be configured to operate any combination of Manual Shutoff and Automatic Shutoff Valve Decouplers and Top Plates.
Most users prefer pendant controlled, pump mounted, and electric control valves for decoupling operations. However, pumps can be configured for remote mounted electric and manual control valves, and with valves for integration into the machine control or machining cell PLC. Pumps can be configured with an automatic pressure monitoring system to assure that the pallets and tombstones are properly pressurized before entering the machine. Pumps can be configured to deliver a different operating pressure to each pallet and tombstone and to deliver different pressures to the Clamp/Unclamp side of double acting circuits. Pumps can be configured to meet your palletized system and control requirements. Contact Vektek for technical assistance.