Expansible chamber devices – With cushioning means effective over a portion only of stroke
Reexamination Certificate
2000-03-06
2001-11-20
Ryznic, John E. (Department: 3745)
Expansible chamber devices
With cushioning means effective over a portion only of stroke
C173S210000, C227S130000
Reexamination Certificate
active
06318239
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a nailer and a bumper provided therein for braking a motion of an impact piston.
2. Description of the Related Arts
Generally, a bumper provided within a nailer is disposed at a lower portion of an impact cylinder, which slidably houses an impact piston. Said bumper is used for braking the impact piston by receiving a bottom surface of the actuated impact piston when the nailer is driving in a fastener such as a nail. The term “nailer” means of an apparatus that includes so called a “tacker” for driving a staple in as well as an apparatus for driving in a various types of nails. In order to absorb an impact efficiently that is made by the impact piston, a volume of the bumper is desirably large. However, in case an outer diameter of the bumper is greater than that of a diameter of the impact piston, an upper surface of the bumper
10
is cracked due to the impact made when it is striked, as shown in FIG.
5
(
a
), and the bumper is damaged. Particularly, in the case where a nailer with the impact piston of a small diameter is used, the bumper
10
may be also small. Therefore, a central hole of the bumper for inserting the driver of the nailer is deformed in accordance with the configuration of the driver, further, a reinforcement to thin parts of the deformed shape caused by the deformation is required. A transverse section of the driver
11
is formed in a rectangular shape so that a transverse section of a central hole
12
of the bumper
10
for inserting the driver
11
, as shown in FIG.
5
(
b
), is formed in an elliptic configuration to surround the driver
11
.
However, in the case where the central hole
12
has the elliptic shape, a stress concentrates on the thin parts of the bumper
10
when the impact is made thereon by the impact piston. Therefore, it was difficult to design the bumper due to the of obtaining an equally distributed balance of load. Further, there was a problem that the performance of absorption and the durability of the bumper were not efficiently developed in reference to the increase in size.
Accordingly, with regard to a nailer by the use of high-pressurized compressed air whose output energy is large when it strikes a nail, and has a small diameter piston, it was difficult to obtain a sufficient size for the bumper. Therefore, it has been very difficult to design a bumper with good performance of absorption and durability.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a bumper and a nailer with said bumper disposed therein, which has a sufficient performance of absorption together with an efficient durability when an impact piston applies an impact on the bumper despite a small size of a diameter of said impact piston.
For attaining the aforementioned object, according to a first aspect of the present invention, there is provided a bumper including an upper part having a transverse section of an annulus ring, an inner surface of the annulus ring having a size to form a void between the inner surface and an outer surface of the upper portion of a driver, and a top surface for receiving an impact piston, the top surface having an outer diameter of the same size as that of the impact piston.
Consequently, there can be obtained a bumper small in size, having high durability and superior shock-absorbing performance.
According to a second aspect of the invention, there is provided a bumper including a transverse section of an annulus ring, an inner surface of the annulus ring having a size to form a void between the inner surface and an outer surface of the upper portion of a driver, and a longitudinal length longer than at least the amount of longitudinal shrinkage of the upper part of the bumper by an impact on collision of an impact piston against the upper part.
Consequently, there can be obtained a bumper having advantages similar to those of a bumper according to a first aspect.
According to a third aspect of the invention, there is provided a nailer equipped with a bumper including an upper part having a transverse section of an annulus ring, an inner surface of the annulus ring having a size to form a void between the inner surface and an outer surface of the upper portion of a driver, and a top surface for receiving an impact piston, the top surface having an outer diameter of the same size as that of the impact piston.
Consequently, there can be obtained a nailer provided with a bumper having advantages similar to those of a bumper according to a first aspect.
According to a fourth aspect of the invention, there is provided a nailer equipped with a bumper including an upper part formed in a shape having a transverse section of an annulus ring, an inner surface of the annulus ring having a size to form a void between the inner surface and an outer surface of the upper portion of a driver, and a longitudinal length longer than at least an amount of longitudinal shrinkage of an upper part of the bumper by an impact on collision of an impact piston against the upper part of the bumper.
Consequently, there can be obtained a nailer provided with a bumper having advantages similar to those of a bumper according to a first aspect.
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patent: 3504840 (1970-04-01), Wandel et al.
patent: 3605559 (1971-09-01), Korth
patent: 3776445 (1973-12-01), Pomeroy
patent: 3871566 (1975-03-01), Elliesen et al.
patent: 4188858 (1980-02-01), Plunkett
patent: 4549344 (1985-10-01), Nikolich
patent: 4824003 (1989-04-01), Almeras et al.
patent: 5056701 (1991-10-01), Bereiter
patent: 5441192 (1995-08-01), Sugita et al.
patent: 5485946 (1996-01-01), Jankel
patent: 5878936 (1999-03-01), Adachi et al.
Max Co. Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ryznic John E.
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