Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
193 words
Pneumatic elevator for handling sheet material of the type including a cylinder, a tubular piston mounted for movement under the force of gravity to the lower end of the cylinder and having a suction nozzle at its distal end, a spring urging the piston towards the upper end of the cylinder against the force of gravity, the piston defining with the cylinder an annular space adapted to be connected to suction means, the interior of the piston also being adapted to be connected to suction means, a plug movably mounted at the top of the cylinder between an upper rest position and a lower operating position at which it acts as an abutment for limiting the further upward displacement of the piston, the plug defining two chambers in the cylinder, a first chamber relatively remote from the piston and communicating with the atmosphere, and a second chamber relative close to the piston and communicating with the interior of the piston, the plug providing valve means adapted to connect said annular space with the suction means in the upper position of the plug and with the atmosphere in the lower position of the plug.
Claim 2
Dependent Claim
193 words
Pneumatic elevator for handling sheet material of the type including a cylinder, a tubular piston mounted for movement under the force of gravity to the lower end of the cylinder and having a suction nozzle at its distal end, a spring urging the piston towards the upper end of the cylinder against the force of gravity, the piston defining with the cylinder an annular space adapted to be connected to suction means, the interior of the piston also being adapted to be connected to suction means, a plug movably mounted at the top of the cylinder between an upper rest position and a lower operating position at which it acts as an abutment for limiting the further upward displacement of the piston, the plug defining two chambers in the cylinder, a first chamber relatively remote from the piston and communicating with the atmosphere, and a second chamber relative close to the piston and communicating with the interior of the piston, the plug providing valve means adapted to connect said annular space with the suction means in the upper position of the plug and with the atmosphere in the lower position of the plug.
Claim 3
Dependent Claim
26 words
Pneumatic elevator according to claim 1, wherein the movable plug is provided with a tubular portion extending towards the piston and having a calibrated pressure-drop orifice.
Claim 4
Dependent Claim
34 words
Pneumatic elevator according to claim 2, wherein the cylinder has a passageway which is closed off by the movable plug in its upper position and short-circuits the calibrated pressure-drop orifice in its lower position.
Claim 5
Dependent Claim
104 words
Pneumatic elevator according to claim 3, wherein the plug has two bearing members, the first chamber being defined to one side of a first bearing member remote from the second bearing member and communicating with the atmosphere, the second chamber being located to one side of the second bearing member remote from the first bearing member and adapted to communicate directly with the interior of the piston, and a third chamber formed about the tubular portion between the first and second bearing members and adapted to be connected to the suction means and communicating with the interior of the piston through the pressure-drop orifice.
Claim 6
Dependent Claim
22 words
Pneumatic elevator according to claim 4, wherein the passageway for short-circuiting the calibrated pressure-drop orifice extends between the second and third chambers.
Claim 7
Dependent Claim
19 words
Pneumatic elevator according to claim 1, wherein an air filter is arranged between the first chamber and the atmosphere.
Claim 8
Dependent Claim
49 words
Pneumatic elevator according to claim 6, wherein the cylinder is opened at least in part at its upper end, a cap superpositioning the open upper end of the cylinder. the air filter being of annular configuration and sandwiched between the open upper end of the cylinder and the cap.
Claim 9
Dependent Claim
20 words
Pneumatic elevator according to claim 7, further comprising rods connecting the cap to the cylinder extending through the air filter.