Pneumatic door closer

Abstract

A pneumatic door closer includes a rotary energy-storing mechanism including a housing and a driving mechanism. The driving mechanism includes a cylinder, a second piston assembly and a sealing element, the sealing element is in an air tight connection with the cylinder and the second piston assembly, to form a closed space filled with high pressure gas in the cylinder. The second piston assembly drives the closed space into a first air chamber and a second air chamber in communication with each other. The driving mechanism also includes a first piston assembly connected to the second piston assembly. The pneumatic door closer also includes a transmission mechanism having one end received in the housing and another end connected to the door frame.

Claims

1. A door closer for dampening closing movement of a door pivotally mounted in a door frame having a track, comprising: a housing adapted to be mounted on the door, and a pneumatic cylinder connected to the housing, the pneumatic cylinder having first and second gas chambers with first and second gas passages between the first and second gas chambers; a rod adapted to be connected to the track in the door frame and to the housing; a cam on one end of the rod in the housing; a first piston in the housing and engaging the cam; a second piston in the pneumatic cylinder between the first and second gas chambers; the rod rotating the cam when the door is opening, so as to move the first piston in a first direction, which in turn moves the second piston in the first direction so as to open the first gas passage between the first and second gas chambers, whereby gas flows from the second gas chamber to the first gas chamber; and wherein when the door is closing, the first passage is closed and gas flows from the first gas chamber to the second gas chamber through the second gas passage.

2. The door closer of claim 1 wherein the second piston seals the first passage when the door is closing and opens the first passage when the door is opening.

3. The door closer of claim 1 wherein the second passage includes a labyrinthine path.

4. The door closer of claim 1 wherein the first and second passages allow air flow in opposite directions between the first and second gas chambers.

5. The door closer of claim 1 further comprising a labyrinthine path in the piston to reduce flow of gas from the first gas chamber to the second gas chamber when the door is closing.

6. The door closer of claim 1 wherein the second piston is slidably mounted in the pneumatic cylinder.

7. The door closer of claim 1 wherein the first and second pistons are co-axial with one another.

8. The door closer of claim 1 wherein the second piston includes a throttle, and the second passage is formed in the throttle.

9. The door closer of claim 8 wherein the throttle includes a labyrinthine gas path with an inlet and an outlet.

10. The door closer of claim 1 wherein movement of the second piston inversely varies the volumes of the first and second chambers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram illustrating a preferred embodiment of the pneumatic door closer of the present invention.

(2) FIG. 2 is a partial sectional schematic diagram of the pneumatic door closer of the embodiment.

(3) FIG. 3 is a sectional diagram of a rotary energy-storing mechanism of the embodiment when the door is opening.

(4) FIG. 4 is a sectional diagram of a rotary energy-storing mechanism of the embodiment when the door is closing.

(5) FIG. 5 is an enlarged sectional diagram illustrating the structural connection of the sealing element, the second piston assembly, and cylinder shown in FIG. 3.

(6) FIG. 6 is a an enlarged sectional diagram illustrating the structural connection of the sealing element, the second piston assembly and cylinder shown in FIG. 4.

(7) FIG. 7 is a sectional view of the throttle ring of the embodiment.

(8) FIG. 8 is a schematic diagram of the throttle ring of the embodiment.

(9) FIG. 9 is a schematic diagram showing the throttle ring and gaskets of the embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(10) In order to sufficiently understand the purpose, characteristics and effect of the present invention, the concept, specific structures and technical effect of the present invention will be further described hereinafter with reference to the FIGS. 1-9.

(11) As shown in FIG. 1, the pneumatic door closer of this embodiment includes a rotary energy-storing mechanism 1, a sliding rail mechanism 2 and a transmission mechanism 3 used to connect the rotary energy-storing mechanism 1 to the sliding rail or track mechanism 2. In FIG. 1, the rotary energy-storing mechanism 1 is mounted at the top of a door 4, and the sliding rail mechanism 2 is mounted at the top of a door frame 5, though these mechanisms can also be mounted at the bottom of the door and the door frame.

(12) FIG. 2 illustrates the installing structure of the pneumatic door closer according to this embodiment. The sliding rail mechanism 2 includes a sliding rail 22 mounted in the door frame 5 and a slider 21 configured on the sliding rail 22. The transmission mechanism 3 includes a rod 31 having one end connected to the slider 21 and the other end connected to the rotary energy-storing mechanism 1.

(13) When the door 4 is opening, the transmission mechanism 3 is driven to move under the movement of door 4, the slider 21 is thereby driven by the rod 31 to slide along the sliding rail 22, and meanwhile the rotary energy-storing mechanism 1 is driven by the transmission mechanism 3, in order to store energy.

(14) When the external force applied on the door 4 disappears, the energy stored in the rotary energy-storing mechanism 1 releases to move the transmission mechanism 3, whereby the rod 31 moves, and it drives the slider 21 to slide along the sliding rail 22, then the door 4 will be closed.

(15) It should be understood that it is just a preferable embodiment to arrange the rotary energy-storing mechanism 1 on the tops of the door 4 and the door frame 5 in the present invention, and that this arrangement is not a restriction for the position of pneumatic door closer of the present invention.

(16) As shown in FIGS. 3 to 8, the rotary energy-storing mechanism 1 includes a housing 100 and a driving mechanism 200 connected thereto.

(17) The driving mechanism 200 includes a cylinder 210, a first piston assembly 220, a second piston assembly 230, and a sealing element 240.

(18) The first piston assembly 220 is mounted within the housing 100. The first piston assembly 220 includes a piston body 221 and a wheel 222 thereon. A recess is provided on the piston body 221 to receive a push rod 231 of the second piston assembly 230.

(19) One end of the second piston assembly 230 is mounted within the cylinder 210, and the other end engages the first piston assembly 220. The sealing element 240 sleeves on the second piston assembly 230, and is in an air tight sealing connection with the cylinder 210 and the second piston assembly 230, to form a closed space filled with high pressure gas 250 in the cylinder 210. High pressure nitrogen is preferably used therein. It is understood that the high pressure gas includes, but is not limited to, high pressure nitrogen. The second piston assembly 230 divides the closed space into a first air chamber 260 and a second air chamber 270 in communication with each other. The first air chamber 260 is located between the second piston assembly 230 and the sealing element 240.

(20) Specifically, the second piston assembly 230 includes the push rod 231 and a fitting component 232 configured thereon. The fitting component 232 resides within the closed space, and contacts the inner wall of the cylinder 210 to divide the closed space into the two air chambers, i.e. the first air chamber 260 and the second air chamber 270, in communication with each other. The first air chamber 260 is adjacent to the sealing element 240, and the second air chamber 270 is spaced away from the sealing element 240.

(21) The fitting component 232 includes a first gasket 2322, a second gasket 2323, a throttle ring 2321 between the gaskets 2322 and 2323, a nut 2324 used to fasten the first and second gaskets and the throttle ring to the push rod 231, and a third sealing ring 2325 configured between the throttle ring and inner wall of the cylinder.

(22) As shown in FIGS. 7-9, the throttle 2321 includes an air inlet 001, an air outlet 002, a vent hole 003, and a throttle passage 004 connecting the air outlet 002 and the vent hole 003.

(23) As shown in FIGS. 5 and 6, when the door is opening, a gap 005 appears between the fitting component 232 and the inner wall of the cylinder 210, such that the high pressure gas 250 flows from the second air chamber 270 into the first air chamber 260 in the direction indicated by the arrows in FIG. 5.

(24) When the external force applied on the door 4 disappears, the third sealing ring 2325 seals off the gap 005, such that the high pressure gas 250 in the first air chamber 260 flows through the air inlet 001, the air outlet 002, the throttle passage 004, and the vent hole 003, in turn, and into the second air chamber 270, in the direction indicated by the arrows in FIG. 6.

(25) The labyrinth path created by passages 001-004 slows down flow of gas from the second chamber 270 to the first chamber 260 to dampen the closing speed of the door 4.

(26) A through-hole 241 is provided in the sealing element 240, and the push rod 231 extends through the through-hole 241 to position the end of the push rod 231 in the recess of the first piston assembly 220. One end of the sealing element 240 is threaded-connected to the housing 100, and the other end is configured within the cylinder 210 and is in air tight sealing connection with the cylinder 210.

(27) Specifically, one end of the sealing element 240 connected to the housing 100 is provided with thread, and the housing 100 is also provided with thread in corresponding position. A first perimeter groove 242 and a second end groove 243 are provided in the sealing element 240.

(28) Preferably, a first sealing ring 244 is configured within the first perimeter groove 242 to seal off the gap between the inner wall of the cylinder 210 and the sealing element 240. A second sealing ring 245 is configured within the second end groove 243 to seal off the gap between the push rod 231 and the sealing element 240.

(29) The transmission mechanism 3 also includes a cam 32 configured within the housing 100, and the rod 31 connected to the cam 32. The cam 32 is connected to the first piston assembly 220.

(30) FIG. 3 is a structural schematic diagram of the rotary energy-storing mechanism according to the embodiment when the door is opening. When the door 4 is opening under external force, the transmission mechanism 3 drives the first piston assembly 220 to move toward the cylinder 210, then the second piston assembly 230 moves away from the sealing element 240 to squeeze the high pressure gas 250 in the second air chamber 270, whereby the high pressure gas 250 in the second air chamber 270 flows through the gap 005 into the first air chamber 260, and the second air chamber 270 decreases in size.

(31) Specifically, when the door is opening under an external force, the slider 21 slides along the sliding rail 22, the rod 31 rotates the cam 32 to push the first piston assembly 220 to move toward the cylinder 210, whereby the first piston assembly pushes the second piston assembly 230 to move away from the sealing element 240, the fitting component 232 squeezes the high pressure nitrogen in the second air chamber 270, and force the high pressure nitrogen to flow into the first air chamber 266 through the 005 gap between the fitting component 232 and the inner wall of the cylinder 210, then the door 4 will be open finally.

(32) FIG. 4 is a structural schematic diagram of the rotary energy-storing mechanism according to the embodiment when the door is closing. When the external force applied on the door disappears, the high pressure gas 250 in the first air chamber 260 and the second chamber 270 will act on both sides of the second piston assembly 230 respectively in contrary direction. The high pressure gas in the first air chamber 260 exerts a first action force on the second piston assembly 230, and the high pressure gas in the second air chamber 270 exerts a second action force on the second piston assembly 232. The forced area in the second air chamber 270 is substantially the cross sectional area of the cylinder 210, but the forced area in the first air chamber 260 is the difference area between the cross sectional areas of the cylinder 210 and push rod 231. Considering the pressures in the first and second air chamber are identical, the second action force is greater than the first action force, so the second piston assembly 230 will move toward the sealing element 240, making the first air chamber 260 decrease in size. Meanwhile, the high pressure gas in the first air chamber 260 will flow through passages 001-004 of the throttle ring 2321 into the second air chamber 270. Specifically, the high pressure gas in the first air chamber 260 flows into the second air chamber 270 through the throttle ring 2321, driving the first piston assembly 220 to move away from the cylinder 210, bringing the transmission mechanism 3 to move and the door closes slowly, avoiding big impact force and noise of the traditional door closer.

(33) The pneumatic door closer of the present invention applies an air pressure control mode to avoid problems in the prior art, such as oil leak and varied speed of closing the door depending on viscosity of hydraulic oil in traditional hydraulic door closer. In addition, the pneumatic door closer of the present invention can be manufactured in low cost, and is environmentally friendly.

(34) The embodiment described hereinbefore is merely preferred embodiment of the present invention and not for purposes of any restrictions or limitations on the invention. It will be apparent that any non-substantive, obvious alterations or improvement by the technician of this technical field according to the present invention may be incorporated into ambit of claims of the present invention.