GB1337167A - Hydraulic operator and circuit therefor - Google Patents

Abstract

1337167 Hydraulic power door operator STANLEY WORKS 2 Dec 1971 [2 Dec 1970] 56043/71 Heading E2M A hydraulic power operator is mounted in use above a door and a power cylinder 12, under the action of hydraulic pressure from motor 20 and accumulator 52, acts on a vertical spindle 36, about which the door pivots, to open it; the door closes under the' action of a double acting spring biassing means 14 which also acts on the spindle. A valve means 16 normally connects cylinder inlet line 72 to reservoir 54, via line 78, but any suitable detecting means can be employed to actuate solenoid 68 and cause it to connect line 72 to pressure line 71. When this occurs piston 74 is pushed to the right driving the spindle 36, via 138, 140, anticlockwise to open the door and store energy in spring means 14. When the solenoid is deenergized line 71 once more connects with reservoir 54 and the spring means 14 closes the door; valves 73, 80 restrict the passage of fluid to and from the pressure side of the piston and control the opening and closing speed of the doors. The cylinder 12, being below the level of the reservoir, is always full of fluid and the opening movement of the piston forces fluid out of chamber 158 via 162, 164, 166 to the reservoir. When the line 72 is under pressure plunger 222 is depressed and holds ball 224 free of seat 226 to permit free fluid passage; but if the door is opened manually the ball 222 can block 226 and the ejected fluid must pass via restriction 230, limiting the manual opening speed. Fig. 4 shows the operation of the power cylinder more clearly. Line 72 connects to chamber 148, and when the door is closed section 194 takes up the position shown dotted. Fluid under pressure passes through conduit 150 through one-way valve 152 to act on the piston 74 in chamber 156. When the door is almost open, section 168 enters chamber 160 and forces the fluid being ejected from chamber 158 to pass through restriction 176 to reach the exit line 162, this causes the door to decelerate. A similar deceleration is produced when the door is almost closed, since as 194 re-enters chamber 148 fluid can only pass through restriction 198. If the door is accidentally opened in the reverse direction the piston will move initially to the left from the dotted position and hydraulic fluid will move past restriction 198. As the door moves further in this direction the drive link 138 reaches an over centre position with respect to spindle 36 and the piston will: move to the right, restriction 230 will limit the flow of fluid as described earlier. Section 194 remains in 148 and when the door closes restriction 198 will affect the flow, then as the over centre position is re-passed movement to the right will be affected by restriction 230. The reverse opening and closing movement of the door is therefore resisted by the passage of fluid through the restrictions 198, 230.