JPH0420944Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a means for ensuring safety when a stay damper that assists in opening and closing a swing door is overcompressed.

(Prior art) As a stay damper 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. It is well known that the piston rod is slidably protruded outward. When this kind of stay damper contracts, the gas enclosed 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 cylinder breaks without being overcompressed, the piston rod, suddenly released from overcompression, may fly out of the cylinder due to the pressure of the compressed gas, potentially causing harm to people or objects nearby.

Therefore, in order to prevent such dangers, 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 Publication No. 61-291216). This is a stay damper installed in a swing door at the rear of an automobile, and is designed to prevent the piston rod from flying forward due to damage to the bracket in the event of an impact such as a rear-end collision and injuring passengers in the rear seat.

(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.

SUMMARY OF THE INVENTION In view of these problems, an object of the present invention is to provide a stay damper equipped with a safety mechanism that can more reliably release the gas sealed inside against the above-mentioned contraction.

(Means for solving the problem) The present invention consists of a piston that is slidably housed in a cylinder filled with gas, and supported by the tip of a piston rod that is slidably inserted into the cylinder in the axial direction. However, in a stay damper for a swing door that assists in opening and closing the swing door by locking one of the base ends of the piston rod and the cylinder to the swing door and the other to the surrounding frame, the piston rod is passed through the piston rod vertically to communicate the inside and outside of the cylinder. A push rod is inserted into this hole and the tip thereof is held in a state protruding in front of the piston.A seal is applied to the outer periphery of the push rod that slides into contact with the hole and blocks gas flow within the hole. At the same time, an enlarged diameter portion larger than the seal diameter is formed in the through hole behind the seal.

(Operation) When the piston enters the deepest part of the cylinder and the push rod collides with the bottom of the cylinder and is pushed up, the seal slips out to the enlarged diameter part behind as the push rod retreats, and the compressed gas in the cylinder passes through the hole. It is emitted to the outside of the cylinder through the cylinder, and the repulsive force of the stay damper is weakened.

(Example) Embodiments of the present invention are shown in FIGS. 1 to 3.

In FIG. 1, 1 is a cylinder filled with gas, 2 is a piston, and 3 is a piston rod.
The piston 2 is slidably housed inside the cylinder 1, and a passage 4 is formed vertically through the piston 2, communicating the upper and lower parts. Piston 2 is piston rod 3
The piston rod 3 protrudes outward from the cylinder 1 in a freely sliding manner. The proximal ends of the cylinder 1 and piston rod 3 are attached to a swing door or frame (not shown) via brackets 5 and 6, respectively.

The piston rod 3 is formed with a through hole 7 that extends vertically through the center and opens at the base end and the distal end, and a through hole 6A that communicates with the atmosphere is formed in the bracket 6 that holds the base end of the piston rod 3. A push rod 8 is inserted into the through hole 7, and the push rod 8 is inserted into the through hole 7.
By tightly fitting the upper end 8A of the large diameter into the upper part of the through hole 7 through the seal 9,
is held in the through hole 7 against the gas pressure. An enlarged diameter portion 7A having a larger diameter than the seal 9 is formed above the upper end portion 8A of the through hole 7, and the through hole 6A of the bracket 6 is opened therein. Further, the tip of the push rod 8 is made to protrude further below the piston 2 from the through hole 7. The diameter of the push rod 8 is set to a size that can ensure a gap 10 between it and the wall surface of the through hole 7 for gas circulation.

On the other hand, a gas filling plug 11 is provided protruding from the bottom of the cylinder 1 opposite to the push rod 8 protruding from the piston 2. This gas filling plug 11 has both the function of sealing the gas filling hole for filling the cylinder 1 and the function of pushing up the push rod 8 when the piston 2 further enters from the maximum compression position.

Next, the action will be explained.

Under normal conditions, the pressure of the gas sealed in the cylinder 1 urges the piston 2 in the direction of extension, and when the piston 2 moves toward the compression side, the gas entering the piston rod 3 is further compressed, resulting in a repulsive force. The system is designed to further strengthen the force and urge the swing door toward the opening side. At this time, the pressure of the compressed gas below the piston 2 also acts on the push rod 8.
The push rod 8, whose upper end 8A is tightly fitted into the through hole 7, will not be displaced by this gas pressure.

By the way, if the piston 2 penetrates deeper than the set maximum compression position due to an abnormal impact, etc., the push rod 8 protruding from the piston rod 3 will close the gas-filled plug 11 protruding from the bottom of the cylinder 1.
The gas-filled plug 11 strongly pushes up the push rod 8. Due to this push-up, the upper end 8A of the push rod 8 comes out together with the seal 9 into the enlarged diameter section 7A, and the gap 10 opens into the enlarged diameter section 7A.
A and the atmosphere through the through hole 6A. As a result, the overcompressed gas in the cylinder 1 is released into the atmosphere, and the repulsive force of the stay damper is weakened.
Even if the brackets 5 and 6 are damaged due to further load, there is no fear that the piston rod 3 will suddenly jump out of the cylinder 1.

In order to ensure that the push rod 8 does not come off during normal operation, an auxiliary rod 12 may be inserted between the push rod 8 and the bracket 6 through the enlarged diameter portion 7A of the through hole 7. In this case, the pushing up force exerted by the gas-filled plug 11 on the push rod 8 during abnormal contraction causes the auxiliary rod 12 to
The strength of the auxiliary rod 12 is set to be weak so that the rod undergoes buckling deformation. Alternatively, after the upper end portion 8A is fitted, the through hole 7 may be caulked or an adhesive may be applied to the fitting portion to strengthen the prevention against gas pressure.

Further, if a thin rod-shaped projection 13 is formed at the lower part of the push rod 8 to abut the through hole 7 as shown in FIG. 3, there is no fear that the push rod 8 will vibrate inside the through hole 7.

(Effects of the invention) As described above, in the present invention, the push rod is inserted and held in the through hole that runs vertically through the piston rod so that it projects forward of the piston, and an enlarged diameter portion is formed in the through hole behind the seal provided on the push rod. When the stay damper contracts beyond the maximum compression position, the push rod is pushed up to the bottom of the cylinder and retreats, and as the seal comes out to the enlarged diameter section, the compressed gas inside the cylinder is released through the through hole to the outside of the cylinder. The repulsive force of the stay damper weakens. Therefore, even if the bracket that locks the stay damper is damaged due to an abnormal impact, it is possible to prevent the piston rod from jumping out of the overcompressed stay damper and causing harm to people or objects.

Further, since the gas is released by pushing up the push rod from the bottom of the cylinder, the operating mechanism is simple and there is little risk of malfunction.

Therefore, according to the present invention, the safety of the stay damper against abnormal loads can be reliably improved with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a stay damper showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the main part of the stay damper showing another configuration for holding the push rod,
FIG. 3 is a longitudinal sectional view showing the shape of the push rod tip. 1...Cylinder, 2...Piston, 3...Piston rod, 7...Through hole, 7A...Enlarged diameter part, 8
...Putshurotsudo, 10...Gap.

Claims (1)

[Scope of utility model registration request] A piston is slidably housed in a cylinder filled with gas, the piston is supported by the tip of a piston rod that is slidably inserted into the cylinder in the axial direction, and one of the base ends of the piston rod and cylinder is connected to a swing door. In a stay damper for a swing door that assists in opening and closing the swing door by locking the other end to the surrounding frame, a through hole is formed through the piston rod vertically to communicate the inside and outside of the cylinder, and the push rod is inserted into this through hole. A seal is applied to the outer periphery of the push rod that slides into contact with the through hole to block gas flow within the through hole, and a seal with a diameter larger than the seal diameter is attached to the through hole behind this seal. A stay damper for a swing door characterized by forming an enlarged diameter portion.