Pneumatic cylinder motor with end-of-travel cushioning mechanism
Cushioning mechanism in a pneumatic cylinder utilizing a supplied air pressure, and a method of cushioning a piston in the pneumatic cylinder. Cushioning chambers are provided at opposite ends of a cylinder body of the pneumatic cylinder. Respective differential pressure valves and relief valves are provided between each of the cushioning chambers and an air supply. A cushioning member is disposed between each cushioning chamber and a cylinder bore. Air supplied under pressure from the air supply is stored in one of the cushioning chambers. When the piston is displaced to push the cushioning member, the air in the cushioning chamber is compressed to cushion the piston. As the cushioning member is moved a prescribed interval, the cushioning chamber is vented to atmosphere.
The present invention relates to a pneumatic cylinder having a cushioning mechanism and a method of cushioning the pneumatic cylinder, and more particularly to a pneumatic cylinder having a cushioning mechanism, with cushioning chambers definedat opposite ends of the pneumatic cylinder, wherein air supplied under pressure to move a piston in one direction is branched, introduced, and stored under pressure in one of the cushioning chambers at a time, and when the piston is moved in an oppositedirection, the stored air under pressure is utilized to dampen the movement of the piston, and also to a method of cushioning the piston in the pneumatic cylinder.
With the foregoing conventional drawbacks in view, it is an object of the present invention to provide a pneumatic cylinder having a cushioning mechanism, with cushioning chambers defined at opposite ends of the pneumatic cylinder, wherein afluid supplied to move a piston is introduced into the cushioning chambers for reliably and quickly dampening the piston which reciprocably moves at high speeds, thereby shortening the time required to actuate the cylinder and achieving a high-speed modeof operation of the cylinder, and wherein the piston will not strike a head cover and a rod cover with an impact to thereby avoid undesired damages or accidents, and also to provide a method of cushioning the piston in the pneumatic cylinder.
According to the present invention, there is provided a pneumatic cylinder with a cushioning mechanism, comprising: a cylinder body having a first cushioning chamber at one end thereof and a second cushioning chamber at an opposite end thereof,the cylinder body having first and second inlet/outlet ports at the ends thereof, respectively, the first inlet/outlet port and the first cushioning chamber communicating with each other through a first air passage, the second inlet/outlet port and thesecond cushioning chamber communicating with each other through a second air passage; a piston slidably movable in the cylinder body; a first cushioning member displaceably mounted in the first cushioning chamber and extending toward the piston for beingpushed thereby; a second cushioning member displaceably mounted in the second cushioning chamber and extending toward the piston for being pushed thereby; an air supply connected to the first and second inlet/outlet ports through a common directionalcontrol valve; a first valve body disposed in the first air passage for adjusting an air pressure from the air supply and supplying the adjusted air pressure into the first cushioning chamber to displace the first cushioning member; a second valve bodydisposed in the second air passage for discharging compressed air from the first cushioning chamber to the first inlet/outlet port when the pressure of air compressed in the first cushioning chamber by the first cushioning member displaced by beingpushed by the piston exceeds a predetermined level; a third valve body disposed in the second air passage for adjusting an air pressure from the air supply and supplying the adjusted air pressure into the second cushioning chamber to displace the secondcushioning member; and a fourth valve body disposed in the second air passage for discharging compressed air from the second cushioning chamber to the second inlet/outlet port when the pressure of air compressed in the second cushioning chamber by thesecond cushioning member displaced by being pushed by the piston exceeds a predetermined level.
The pneumatic cylinder also includes a piston rod having an end attached to the piston, the first cushioning member comprising a shaft for engaging one end face of the piston and a disk movable in unison with the shaft within the first cushioningchamber, the first cushioning member being normally pressed toward the piston by a pressing member disposed in the first cushioning chamber, the second cushioning member comprising a cylindrical body for engaging an opposite end face of the piston withthe piston rod extending through the cylindrical body and a disk movable in unison with the cylindrical body within the second cushioning chamber, the second cushioning member being normally pressed toward the piston by a pressing member disposed in thesecond cushioning chamber.
The pneumatic cylinder also includes a head cover mounted on the one end of the cylinder body, a first wall disposed in the cylinder body and having an end directed toward the head cover, the first cushioning chamber being defined by the headcover, the first wall, and the end of the first wall, a rod cover mounted on the opposite end of the cylinder body, and a second wall disposed in the cylinder body and having an end directed toward the rod cover, the second cushioning member beingdefined by the rod cover, the second wall, and the end of the second wall.
The pneumatic cylinder further includes resilient rings mounted respectively on the disks, the resilient rings blocking communication between the passage communicating between the two chambers and the passage vented to atmosphere when the firstand second cushioning members are displaced toward the piston.
According to the present invention, there is also provided a method of cushioning a pneumatic cylinder having a cylinder body with a piston slidably disposed therein and a piston rod attached thereto, the cylinder body having a cushioning chamberwith a cushioning member displaceably mounted therein and engageable with the piston, and a valve body communicating with the cushioning chamber, the comprising the steps of: supplying air under pressure from an air supply into the pneumatic cylinder tomove the piston and the piston rod reciprocally; introducing an air flow branched from the supplied air into the cushioning chamber and simultaneously displacing the cushioning member; bringing the piston into pushing engagement with the cushioningmember in response to reciprocating movement of the piston and the piston rod to compress air stored in the cushioning chamber; and discharging the compressed air from the cushioning chamber through the valve body out of the cylinder body for therebycushioning the piston.
Processing your request, Please wait....
