JPH045787Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a means for ensuring safety when a stay damper that assists in opening and closing a swing door receives an abnormal load such as an impact.

(Prior art) As a stay damper that is interposed between the surrounding frame and the swing door to assist in opening and closing, a piston is housed in a cylinder filled with gas so that it can slide freely. A piston rod in which the piston rod protrudes freely to the outside is well known. When such a stay damper contracts, the gas filled in it is compressed and the repulsive force is strengthened, so when the stay damper is fully contracted due to the action of an abnormal compression force such as an impact, the bracket holding the piston rod may not be able to withstand the load. If the piston rod breaks without being over-compressed, the piston rod, suddenly released from overcompression, may be ejected from the cylinder by the gas pressure.

Therefore, in order to prevent this phenomenon, a part of the sealed cylinder is damaged in response to abnormal compression force, and the gas inside the cylinder is released into the atmosphere to prevent the piston rod from protruding. A stay damper with such safety measures has been proposed (Japanese Patent Application Laid-Open No. 61-291216). This is designed to prevent the piston rod from flying forward even if the bracket is damaged in response to an impact such as a rear-end collision of a stay damper installed in a swing door at the rear of an automobile.

(Problem that the invention aims to solve) However, in the case of this stay damper, the cylinder is damaged when the load exceeds a certain value, so slight errors in processing and assembling the parts can cause the difference between the design load and the actual load at failure. There was a problem that there was a considerable difference between the two, making it difficult to ensure reliable operation.

In view of these problems, it is an object of the present invention to provide a stay damper that can more reliably release the gas sealed therein against abnormal contraction.

(Means for Solving the Problems) The present invention includes a piston that is slidably housed inside a cylinder filled with gas, a piston rod coupled to the piston that is slidably protruded from a cylinder, and the protruding end In a stay damper for a swing door, which supports opening and closing of the swing door by locking the base end of the cylinder and the base end of the cylinder to the swing door and the surrounding frame through brackets, The opening formed at the bottom communicates with the atmosphere.A gas passage with a larger diameter than the opening is provided through the inside of the bracket, and the tip of the piston or piston rod that enters near the deepest part of the cylinder collides with the gas passage behind. This opening is closed with a plug that falls out.

(Operation) When the piston rod penetrates deep into the cylinder due to an abnormal load such as an impact, the piston or the tip of the piston rod collides with the plug at the bottom of the cylinder, causing the plug to fall from the opening into the large diameter gas passage behind it. This allows the inside of the cylinder to communicate with the atmosphere, and the sealed gas is discharged into the atmosphere through the gas passage.

(Example) FIG. 1 shows an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a cylinder filled with gas, and a piston 2 is slidably housed inside the cylinder, and a piston rod 3 is connected to the piston 2, which protrudes from the tip of the cylinder 1 so as to slide freely. The end of the piston rod 3 is locked to either the swing door or the surrounding frame via a ball-shaped bracket 4, and the base end of the cylinder 1 is locked to the other via a bracket 5. A passage 6 is vertically provided in the piston 2 to allow gas to flow on both sides during sliding. The piston rod 3 is in sliding contact with a bearing 7 at the tip of the cylinder 1 and a seal 9 made of an elastic material, and is freely displaceable in the axial direction and supported in an oil-tight manner. 10 is an elastic member that prevents the piston 2 from being extended.

A gas passage 8 that passes through the bracket 5 and communicates with the atmosphere opens at the bottom of the cylinder 1 facing the piston 2. This gas passage 8 passes from an opening 8A formed at the center of the bottom of the cylinder 1 through a large diameter passage 8B formed coaxially with the opening 8A inside a joint 11 that connects the bracket 5 and the cylinder 1. , are opened on the side surface of the bracket 5 and communicated with the atmosphere. A plug 12 is press-fitted into the opening 8A to prevent the sealed gas from flowing out, and a protrusion 13 is formed at the tip of the piston rod 3 to allow the plug 12 to fall into the passage 8B behind it. The protrusion 13 may be formed by embedding a cylindrical plug in the tip of the piston rod 3. The plug 12 is press-fitted with enough force to prevent it from falling out due to the gas pressure in the cylinder 1, and the distance between the protrusion 13 and the plug 12 is set to such an extent that some clearance remains when the piston 2 is in its normal maximum compression position. .

When assembling the stay damper, gas is injected from the opening 8A at the bottom of the cylinder 1. After that, the plug 12 is press-fitted into the opening 8A, and the joint 11 is fixed to the bottom of the cylinder 1 by welding, and then the bracket 5 is attached to the joint 11. It is caulked and fixed to the outer periphery of.

Next, the action will be explained.

Under normal conditions, the piston 2 does not enter the cylinder 1 beyond the set maximum compression position, and the protrusion 13 does not come into contact with the plug 12. In addition, the plug 12 press-fitted into the opening 8A does not fall out even if it receives the most compressed gas pressure.

However, when a strong compression force acts on the stay damper due to an abnormal impact, etc., and the piston 2 slides beyond the maximum compression position, the protrusion 13 collides with the plug 12, and the plug 12 falls into the passage 8B behind it. do.
As a result, the gas sealed in the cylinder 1 is released into the atmosphere through the passage 8, and the repulsive force exerted on the piston 2 disappears almost instantly. Therefore, even if the brackets 4 and 5 are damaged due to being unable to withstand the load caused by the impact, there is no fear that the piston rod 3 will fly out from the overcompressed cylinder 1.

(Effects of the invention) As described above, the invention communicates the opening formed at the bottom of the cylinder with the atmosphere through a large-diameter gas passage, and collides with the piston or piston rod that has entered near the deepest part of the cylinder and falls off. Since this opening is closed with a plug, if the piston slides to the deepest point due to an abnormal impact, etc., the piston or piston rod will collide with the plug, causing the plug to fall from the opening into the large diameter gas passage, causing the internal seal to close. Release gas into the atmosphere. Therefore, the stay damper instantly loses its repulsive force, and even if the bracket is damaged by impact, it is possible to prevent the piston rod from jumping out of the cylinder.

Moreover, since the present invention has a simple configuration, it can be implemented at a small cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a stay damper showing an embodiment of the present invention. 1... Cylinder, 2... Piston, 3... Piston rod, 5... Bracket, 8... Gas passage, 8A... Opening, 8B... Passage, 12...
Plug, 13...protrusion.

Claims (1)

[Scope of utility model registration request] A piston is slidably housed inside a cylinder filled with gas, a piston rod connected to the piston is slidably protruded from the cylinder, and the protruding end and the base end of the cylinder are connected to one another through a bracket. In a stay damper for a swing door, which locks one to the swing door and the other to the surrounding frame to assist in opening and closing the swing door, an opening formed at the bottom of the cylinder facing the piston is connected to an opening communicating with the atmosphere. A large-diameter gas passage is provided through the inside of the bracket, and this opening is closed with a plug that collides with the tip of the piston or piston rod that enters near the deepest part of the cylinder and falls into the gas passage behind. Stay damper for swing doors.