Spring devices – Elastic extension devices – Compression spring
Reexamination Certificate
1999-11-03
2001-04-24
Graham, Matthew C. (Department: 3613)
Spring devices
Elastic extension devices
Compression spring
C267S034000, C267S226000, C267S291000
Reexamination Certificate
active
06220583
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an air damper, and more particularly, to a cylinder type air damper that can suitably be used with a glove box or the like in an automobile.
As shown in
FIG. 8
, a conventional air damper
20
of this type comprises a cylindrical cylinder
21
whose opposite ends are open, a piston
22
to which a base end of a string
23
is connected for moving within the cylinder
21
, an endcap
26
having a valve
25
for opening and closing a communication hole
24
which is open at one end opening of the cylinder
21
, a guide cap
27
for guiding the movement of the string
23
at the other end open side of the cylinder
21
, and a compression coil spring
28
interposed between the guide cap
27
and the piston
22
in the cylinder
21
.
When this air damper is used in a glove box of an automobile, the cylinder
21
is fixed at the side of an instrument panel, and a tip end
23
b
of the string
23
extending from the guide cap
27
of the cylinder
21
to the outside is fixed to the side of the glove box. As the door of the glove box is moved to its open position, the string
23
is gradually pulled out from the cylinder
21
, and the piston
22
is moved in the same direction against the spring pressure of a compression coil spring
28
. With this operation, a damper effect is obtained by a flowing resistance of air passing through an orifice (not shown) which is opened toward the piston
22
, to ensure that the glove box is slowly moved toward its open position.
When the door of the glove box is moved into its closed position, the piston
22
together with the string
23
is forcibly pushed back into the cylinder
21
by the spring pressure of the compression coil spring
28
, and air accumulated in the cylinder
21
is released to the outside from the end cap
26
through the communication hole
24
which is opened by the valve
25
. Therefore, the piston
22
is swiftly moved within the cylinder
21
, which facilitates the closing operation of the glove box.
SUMMARY OF THE INVENTION
In the conventional air damper, however, if the air damper is examined in more detail, when the base end
23
a
of the string
23
is connected to the piston
22
, as shown in
FIG. 9
, a side of the piston
22
which also serves as a mounting seat of the compression coil spring
28
is integrally formed with a connection cylinder
29
. The connection cylinder
29
is formed with a pair of resilient lock claws
30
. On the other hand, a separate clip
31
formed with a slit
31
a
is mounted to the base end
23
a
of the string
23
. When the clip
31
is fitted into the connection cylinder
29
, the resilient lock claws
30
become locked, thereby connecting the base end
23
a
of the string
23
to the piston
22
.
Therefore, in the case of the conventional air damper, there are numerous parts that comprise the clip body
31
. Further, when the base end
23
a
of the string
23
is connected to the piston
22
, the base
23
a
of the string
23
is mounted to the clip
31
through the slit
31
a
and then, the clip
31
must be locked to the connection cylinder
29
of the piston
22
. As a result, many steps are required to assemble the camper assembly.
The present invention overcomes the disadvantages of conventional air dampers listed above. It is an object of the invention to provide an air damper with a minimal number of parts and effectively facilitates assembly.
An air damper of the present invention is provided with: a cylinder whose one end is closed and the other end is opened; a piston which is movable along an axial direction of the cylinder within the cylinder in a state where an end of a string is connected to the piston; a recess groove formed in an peripheral surface of the piston; an O-ring sealing between the cylinder and the piston and movably fitted to the recess groove; a coil spring butted against one of a pair of flanges defining the recess groove of the piston for biasing the piston toward the one end of the cylinder; a hook provided on the one of the pair of flanges, the end of the string being attached to the hook; and opposed notches formed by notching portions of the pair of flanges of the piston corresponding to opposite sides of the hook.
With this structure, an operator inserts his or her finger, a jig or the like into the spaces of the notches to easily hook the end of the string to the hook, and he or she can mount the string to the piston. Therefore, no additional parts are required and efficient assembly is realized. Further, since the hook itself is small, it is possible to obtain an air damper having a small and rigid piston.
Preferably, each of the notches is formed such that the notch spreads in a diametrical direction of the cylinder.
Further, one of the flanges is preferably provided with a wall for supporting a seat winding portion of the coil spring such that the wall stands so that the coil spring is reliably and easily mounted.
Here, it is preferable that the wall is plurally provided such as to be opposed in a direction substantially perpendicular to a direction along which the opposed notches are provided such as to be located inside of the coil spring.
According to such a structure, since the walls and the hook are disposed along one straight line to avoid the notches, assembly is reliably enhanced. In addition, since the width and the height of the wall can be increased, the coil spring can be mounted more reliably.
An orifice may be provided in the recess groove of the piston in a diametrical direction of the piston.
In such a case, a recess is preferably provided in a periphery of one of opposite ends of the orifice which is located outside in the diametrical direction of the cylinder so that foreign matter, such as fiber pieces and the like caused by contact with the string at the time of assembly, can be prevented from blocking the orifice.
Further, an orifice may be provided in the piston in a direction substantially parallel to the axial direction of the piston.
In such a case, if a recess is provided around the periphery of one of opposite ends of the orifice which is located at the side of the other end of the cylinder, it is preferable because foreign matter such as fiber pieces and the like caused by contact with the string at the time of assembly can be prevented from blocking the orifice.
Further, the orifice is preferably located in a central portion of one flange of the piston so that a damping force is reliably generated with a simple structure.
When the orifice is provided in a direction substantially parallel to the axial direction of the piston, it is preferable that the orifice is located at a position where a movable limit locus determined by a peripheral length of the end of the string does not interfere with the orifice, because foreign matter such as fiber pieces and the like caused by contact with the string at the time of assembly can be prevented from blocking the orifice.
Preferably, the hook includes a tip end that is inclined inwardly in a diametrical direction of the cylinder, so the string can be reliably mounted.
Further, it is preferable that one flange is provided with a wall supporting the seat winding portion of the coil spring in a standing manner, and a rib is provided between the hook and the wall, so that the rigidity of the hook can be secured.
Further, it is preferable that each pair of flanges defining the recess groove of the piston include a small diameter portion, because influence of a burr generated during formation can be eliminated.
REFERENCES:
patent: 5333845 (1994-08-01), Seiichi
Graham Matthew C.
Howard & Howard
Piolax Inc.
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