U.S. patent application number 09/727208 was filed with the patent office on 2001-11-08 for tensioner with plunger stopper pin.
Invention is credited to Nakakubo, Katsuya, Wakabayashi, Naoki.
Application Number | 20010039223 09/727208 |
Document ID | / |
Family ID | 18336396 |
Filed Date | 2001-11-08 |
United States Patent
Application |
20010039223 |
Kind Code |
A1 |
Wakabayashi, Naoki ; et
al. |
November 8, 2001 |
Tensioner with plunger stopper pin
Abstract
A tensioner has a substantially U-shaped stopper pin hooked at
opposite end parts on a tensioner body and part of a plunger,
respectively, to keep the plunger in a retracted position against
the force of a spring before the tensioner is mounted to an engine
body at an appropriate position relative to a power transmitting
chain.
Inventors: |
Wakabayashi, Naoki; (Osaka,
JP) ; Nakakubo, Katsuya; (Osaka, JP) |
Correspondence
Address: |
DANN DORFMAN HERRELL & SKILLMAN
SUITE 720
1601 MARKET STREET
PHILADELPHIA
PA
19103-2307
US
|
Family ID: |
18336396 |
Appl. No.: |
09/727208 |
Filed: |
November 30, 2000 |
Current U.S.
Class: |
474/111 ;
474/140 |
Current CPC
Class: |
F16H 2007/0806 20130101;
F16H 7/08 20130101; F16H 2007/0878 20130101 |
Class at
Publication: |
474/111 ;
474/140 |
International
Class: |
F16H 007/08 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 1999 |
JP |
340379/1999 |
Claims
What is claimed is:
1. A tensioner comprising: a tensioner body; a plunger slidably
mounted on the tensioner body and normally urged in a direction to
project outward from the tensioner body; and a substantially
U-shaped stopper pin having opposite end parts hooked on a part of
the tensioner body and a part of the plunger, respectively, to hold
the plunger in position against movement in the direction to
project from the tensioner body.
2. A tensioner according to claim 1, wherein the tensioner body has
a pin retaining hole formed in an outer surface thereof and
extending perpendicularly to the axis of the plunger, the plunger
has a plastic shoe provided as an integral part on a front end of
the plunger, the shoe having a pin retaining hole formed therein
and extending perpendicularly to the axis of the plunger, one of
the opposite end parts of the U-shaped stopper pin is engaged in
the pin retaining hole in the tensioner body, and the other end
part of the U-shaped stopper pin is engaged in the pin retaining
hole in the shoe.
3. A tensioner according to claim 2, wherein the U-shaped stopper
pin is formed from a resilient metal wire, the pin retaining hole
in the tensioner body has a diameter slightly larger than the
diameter of the metal wire of the stopper pin, and the retaining
hole in the shoe is a rectangular hole much larger in diameter than
the metal wire of the stopper pin.
4. A tensioner according to claim 3, wherein, when the U-shaped
stopper pin is in its free state, the opposite end parts of the
stopper pin are inclined toward each other.
5. A tensioner according to claim 4, wherein the U-shaped stopper
pin further has a center part extending between the opposite end
parts, the center part being spaced from the tensioner body and the
shoe in a radial direction of the plunger.
6. A tensioner according to claim 1, wherein said tensioner body
has a pin retaining hole formed in an outer surface thereof and
extending perpendicularly to the axis of the plunger, the plunger
has a pin retaining hole formed in an outer surface thereof and
extending perpendicularly to the axis of the plunger, one of the
opposite end parts of the U-shaped stopper pin is engaged in the
pin retaining hole in the tensioner body, and the other end part of
the U-shaped stopper pin is engaged in the pin retaining hole in
the plunger.
7. A tensioner according to claim 6, wherein the U-shaped stopper
pin is formed from a resilient metal wire, the pin retaining hole
in the tensioner body and the pin retaining hole in the plunger
have a diameter slightly larger than the diameter of the metal wire
of the stopper pin, and the opposite end parts of the stopper pin
are parallel to each other.
8. A tensioner according to claim 7, wherein the U-shaped stopper
pin further has a center part extending between the opposite end
parts, the center part being spaced from the tensioner body and the
plunger in a radial direction of the plunger.
9. A tensioner according to claim 1, wherein said tensioner body
has a pin retaining hole formed in an outer surface thereof and
extending perpendicularly to the axis of the plunger, the plunger
has a front end face extending perpendicularly to the axis of the
plunger, one of the opposite end parts of the U-shaped stopper pin
is engaged in the pin retaining hole in the tensioner body, and the
other end part of the U-shaped stopper pin is engaged on the front
end face of the plunger.
10. A tensioner according to claim 9, wherein the U-shaped stopper
pin further has a center part extending between the opposite end
parts, the center part being spaced from the tensioner body and the
plunger in a radial direction of the plunger.
11. A tensioner according to claim 9, wherein, when the U-shaped
stopper pin is in its free state, the opposite end parts of the
stopper pin are inclined toward each other.
12. A tensioner according to claim 1, wherein the stopper pin has a
center part extending between the opposite end parts, the center
part being looped to form a ring-like pull tab.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to a tensioner for
applying an appropriate tension to a timing chain or timing belt of
an engine, and more particularly to a tensioner equipped with a
plunger stopper pin that holds a spring-loaded plunger in position
against movement in a direction projecting from the tensioner body
before the tensioner is assembled to the engine.
[0003] 2. Description of the Related Art
[0004] A tensioner is used with a timing chain arranged to transmit
a power between a crankshaft and a camshaft of an engine. The
tensioner has a plunger that is urged by a spring to thrust outward
from the tensioner body. When the tensioner is to be assembled to
the engine, the plunger is needed to be pushed inside the tensioner
body in advance against the force of the spring.
[0005] Accordingly, in the tensioner disclosed in the Japanese
Patent No. 2895784, a stopper pin is inserted through a pin hole in
the tensioner body into a pin hole in the plunger to thereby lock
the plunger in position against the movement in a direction
projecting from the tensioner body.
[0006] Another tensioner disclosed in the Japanese Patent Laid-open
Publication No. HEI-7-42804 includes a plunger having a annular pin
stopper groove formed therein, and a stopper pin inserted through a
hole in the tensioner body into the pin stopper groove until a
front end of the pin is caught by a side wall of the pin stopper
groove. Thus, the plunger is prevented from thrusting out.
[0007] However, since the stopper pins used in the conventional
tensioners comprise a needle-like stopper pin, the pin hole or the
pin stopper groove formed in the plunger must be aligned with the
pin hole in the tensioner body before the needle-like stopper pin
is inserted. When the stopper pin is inserted through from the
outside of the plunger or the outside of the tensioner body, the
pin hole on the tensioner body or the pin stopper groove on the
plunger lies in hiding. This makes it impossible to visually
confirm the position of the pin hole or the pin stopper groove.
Accordingly, it is very difficult to carry out the work to insert
the stopper pin therein, and a great deal of time has been required
for the work to insert the stopper pin.
[0008] Further, in the conventional tensioner having an annular pin
stopper groove formed in the plunger, the man-hour to form the
stopper groove is additionally needed.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the invention to provide a
tensioner having structural features which can hold a plunger onto
a tensioner body with a simple structure.
[0010] Another object of the invention is to provide a tensioner
having a stopper that can be easily mounted to the tensioner body
by a visual confirmation.
[0011] A further object of the invention is to provide a tensioner
capable of easily holding a plunger to the tensioner body by a
stopper pin, utilizing the shape and structure of an existing
component.
[0012] According to the present invention, there is provided a
tensioner comprising: a tensioner body; a plunger slidably mounted
on the tensioner body and normally urged in a direction to project
outward from the tensioner body; and a substantially U-shaped
stopper pin having opposite end parts hooked on a part of the
tensioner body and a part of the plunger, respectively, to hold the
plunger in position against movement in the direction to project
from the tensioner body.
[0013] In one preferred form of the invention, the tensioner body
has a pin retaining hole formed in an outer surface thereof and
extending perpendicularly to the axis of the plunger, and the
plunger has a plastic shoe provided as an integral part on a front
end of the plunger, the shoe having a pin retaining hole formed
therein and extending perpendicularly to the axis of the plunger.
One of the opposite end parts of the U-shaped stopper pin is
engaged in the pin retaining hole in the tensioner body, and the
other end part of the U-shaped stopper pin is engaged in the pin
retaining hole in the shoe.
[0014] It is preferable that the stopper pin is formed from a
resilient metal wire. The pin retaining hole in the tensioner body
has a diameter slightly larger than the diameter of the metal wire
of the stopper pin, and the retaining hole in the shoe is a
rectangular hole much larger in diameter than the metal wire of the
stopper pin.
[0015] When the plunger is to be locked in its retracted position,
the plunger is pushed into the tensioner body, then the stopper pin
is attached to the tensioner body and the shoe such that the
opposite end parts of the stopper pin are engaged in the respective
pin retaining holes of the tensioner body and the shoe. Since the
pin retaining holes are formed on the outside surfaces of the
tensioner body and the shoe, the pin attachment work can be easily
achieved under visual observation. The pin retaining hole in the
shoe is much larger in diameter than the stopper pin. This
facilitates smooth attachment of the stopper pin to the shoe.
[0016] When the U-shaped stopper pin is in its free state, the
opposite end parts of the stopper pin may be inclined toward each
other. The inclined opposite end parts can exert an increased
retaining force on the plunger.
[0017] The U-shaped stopper pin further has a center part extending
between the opposite end parts. The center part is spaced from the
tensioner body and the shoe in a radial direction of the plunger.
The center part thus arranged can be easily gripped when the
stopper pin is to be removed from the tensioner.
[0018] In another preferred form of the invention, the tensioner
body has a pin retaining hole formed in an outer surface thereof
and extending perpendicularly to the axis of the plunger, and the
plunger has a pin retaining hole formed in an outer surface thereof
and extending perpendicularly to the axis of the plunger. One of
the opposite end parts of the U-shaped stopper pin is engaged in
the pin retaining hole in the tensioner body, and the other end
part of the U-shaped stopper pin is engaged in the pin retaining
hole in the plunger. The pin retaining hole in the tensioner body
and the pin retaining hole in the plunger may have a diameter
slightly larger than the diameter of the metal wire of the stopper
pin, and the opposite end parts of the stopper pin may be parallel
to each other.
[0019] In a further preferred form of the invention, the tensioner
body has a pin retaining hole formed in an outer surface thereof
and extending perpendicularly to the axis of the plunger, and the
plunger has a front end face extending perpendicularly to the axis
of the plunger. One of the opposite end parts of the U-shaped
stopper pin is engaged in the pin retaining hole in the tensioner
body, and the other end part of the U-shaped stopper pin is engaged
on the front end face of the plunger.
[0020] The stopper pin may have a center part extending between the
opposite end parts and looped to form a rink-like pull tab. The
ring-like pull tab facilitate the stopper pin removing work.
[0021] The above and other objects, features and advantages of the
present invention will become apparent to those versed in the art
upon making reference to the following detailed description and
accompanying sheets of drawings in which a preferred structural
embodiment of the present invention is shown by way of illustrative
example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a front view of a tensioner according to a first
embodiment of the present invention;
[0023] FIG. 2 is a sectional view of the tensioner shown in FIG.
1;
[0024] FIG. 3 is a front view of a modified stopper pin according
to the present invention;
[0025] FIG. 4 is a sectional view of a tensioner according to a
second embodiment of the present invention; and
[0026] FIG. 5 is a sectional view of a tensioner according to a
third embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Certain preferred structural embodiments of the present
invention will be described with reference to the accompanying
drawings. FIG. 1 and FIG. 2 illustrate a tensioner according to a
first embodiment of the present invention.
[0028] As generally known, the tensioner has a function to adjust a
tension in a chain or a belt or the like. In case of an automobile
engine, for example, a chain is wound around a crank sprocket and a
cam sprocket, and the tensioner is used in order to prevent the
chain from a slack and apply a constant tension to the chain.
[0029] As shown in FIGS. 1 and 2, a tensioner 10 is provided with a
plunger 12 having a thrusting force applied thereto in order to
apply a tension to a chain C. The plunger 12 is slidably fitted in
a cylindrical hollow part of a tensioner body 14. Between the
plunger 12 and the tensioner body 14 is disposed a compression coil
spring 16 that applies a thrusting force to the plunger 12.
Accordingly, the plunger 12 is needed to be pushed or forced into
the tensioner body 14 against the force of the spring 16, when the
tensioner 10 is mounted on a fixed member such as an engine block
(not shown).
[0030] According to the present invention, use of a specific
stopper pin 18 and a structure related to the stopper pin 18
enables easy assembling and disassembling of the stopper pin 18
relative to the tensioner 10, as will be described below.
[0031] As shown in detail in FIG. 1 and FIG. 2, the tensioner body
14 has a pin retaining hole 20 (FIG. 2) formed on an outer surface
thereof. The plunger 12 has a plastic shoe 22 on the front end
thereof, and the shoe 22 has a pin retaining hole 24 formed
thereon. The stopper pin 18 is pinned in the pin retaining holes 20
and 24, thereby locking the plunger 12 in position against movement
in a direction projecting from the tensioner body 14.
[0032] The pin retaining hole 20 formed in the tensioner body 14 is
a blind hole extending perpendicularly to the circumference of the
tensioner body 14. The pin retainer hole 20 extends in a radial
direction of the cylindrical hollow part of the tensioner body 14
in which the plunger 12 is slidably movable. The pin retaining hole
24 formed in the plunger 12 is a bottomed relatively large
rectangular hole formed at the same time the plastic shoe 22 is
molded. The pin retaining hole 24 extend in a radial direction the
plunger 12.
[0033] The stopper pin 18 is formed from a resilient metal wire in
a substantially U shape with opposite end parts slightly converged.
The stopper pin 18 has a center part 26 and a pair of end parts 28,
28. The length of the end parts 28 is greater than the depth of the
pin retaining holes 20, 24 so that after the stopper pin 18 is
mounted onto the plunger 12 and the tensioner body 14, the center
part 26 stays with a certain gap from the surfaces of the plunger
12 and the tensioner body 14.
[0034] As shown in FIG. 2, when the plunger 12 is pushed inside to
hook the stopper pin 18 in the pin retaining holes 20, 24, both of
the pin retaining holes 20, 24 can be confirmed visually. This
makes the pin-mounting work easier than the conventional. Further,
since the pin retaining hole 24 in the plunger 12 is a relatively
large rectangular hole formed integrally with the plastic shoe 22,
one end part 28 of the stopper pin 18 can be easily hooked into the
pin retaining hole 24 without alignment with high positioning
accuracy.
[0035] After the tensioner 10 is mounted onto an engine block or
the like fixed member, since the center part 26 of the stopper pin
18 stays floating or spaced from the plunger 12 and the tensioner
body 14, the stopper pin 18 can easily be removed by pulling the
center part 26 outward away from the plunger 12 and the tensioner
body 14. Upon detachment or removal of the stopper pin 18, the
plunger 12 is extruded by the compression spring 16 to an operating
position in which the shoe 22 can exert an appropriate tension to
the chain C.
[0036] FIG. 3 illustrates a modified form of the stopper pin. The
modified stopper pin 18a has a center part 26a looped to form a
ring-shaped pull tab 30 for facilitating removal or detachment of
the stopper pin 18a from the tensioner. When the stopper pin 18a is
to be removed, the ring-shaped pull tab 30 is pulled outward with a
finger hooked thereon. Opposite end parts 26a of the stopper pin
18a are bent perpendicularly from both sides of the center part
26a. The length of the front parts 28a is sufficient with such a
length that it can be hooked in the pin retaining holes 20, 24.
[0037] FIG. 4 is a sectional view of a tensioner according to a
second embodiment of the present invention. The tensioner 10b
includes a plunger 12b, a tensioner body 14b, and a compression
coil spring 16b in the same manner as the tensioner 10 shown in the
first embodiment.
[0038] The tensioner body 14b has a pin retaining hole 20b formed
in an outer surface thereof, the plunger 12b also has a pin
retaining hole 24b formed in an outer surface thereof. The pin
retaining hole 20b of the tensioner body 14b is a radial through
hole in this embodiment, however it may be a blind hole in the same
manner as in the first embodiment. The pin retaining hole 24b of
the plunger 12b is a radial blind hole. The pin retaining holes
20b, 24b are perpendicular to outer surfaces of the tensioner body
14b and the plunger 12b. More specifically, the pin retaining holes
20b, 24b are perpendicular to the axis of the plunger 12b.
[0039] A stopper pin 18b is formed by bending a metal wire into a
generally U shape having a center part 26b and opposite end parts
28b, 28b bent perpendicularly from both sides of the center part
26b. One end part 28b is made longer than the other end part so
that it can be pinned in the pin retaining hole 24b on the plunger
12b. In this embodiment, each of the pin retaining holes 20b, 24b
has a slightly larger diameter than the wire diameter of the
stopper pin 18b, and the end parts 28b, 28b are formed parallel to
each other, accordingly.
[0040] In the tensioner 10b of the second embodiment, the plunger
12b comes in contact with a shoe provided on a mating part. Thus,
the plunger 12b has the pin retaining hole 24b formed in itself.
When the plunger 12b is not provided with the shoe in this manner,
the plunger 12b is so formed as to have a pin retaining hole 24b so
that the generally U-shaped stopper pin 18b can be used for locking
the plunger 12b in position against movement in a direction to
project from the tensioner body 14b.
[0041] FIG. 5 shows in cross sectional a tensioner according to a
third embodiment of the present invention. The tensioner 10c
includes a plunger 12c, a tensioner body 14c, and a compression
coil spring 16c in the same manner as in the first embodiment.
[0042] The tensioner body 14c has a blind pin retaining hole 20c
formed in an outer surface thereof. The plunger 12c is not provided
with a pin retaining hole in an outer surface thereof. A stopper
pin 18c is formed in a substantially U shape with a center part 26c
and opposite end parts 28c, 28c bent perpendicularly from both ends
of the center part 26c. In this embodiment, a front end face 32 of
the plunger 12c is formed flat, and the one end part 28c of the
substantially U-shaped stopper pin 18c is hooked in the pin
retaining hole 20c, and the other end part 28c is hooked on the
front face 32 of the plunger 12c.
[0043] Since the plunger 12c has no pin retaining hole formed
therein, the mechanical strength of the plunger 12c is higher than
those shown in FIGS. 1 and 4. It is also possible to save the
man-hour to make the pin retaining hole. In this embodiment, a
stopper pin having end parts converged each other in the same
manner as the first embodiment shown in FIG. 1 can be employed.
[0044] In order to assemble the stopper pin 18c, the plunger 12c is
pushed inside, and the end parts 28c, 28c of the stopper pin 18c
are hooked in the pin retaining hole 20c and on the front face 32,
respectively. As an alternative, after one end part 28c of the
stopper pin 18c is hooked in the pin retaining hole 20c, the
stopper pin 18c is turned about the hooked end part 28c in such a
manner that the other end part 28c is hooked on the front face 32
of the plunger 12c. Thus, the plunger 12c is prevented from
thrusting out from the tensioner body 14c.
[0045] As described above, tensioners according to the present
invention have structural features which enable easy assembly of a
stopper pin onto a tensioner body and a part of the plunger under
visual observation, which significantly enhances efficiency in the
assembling work.
[0046] Obviously, various minor changes and modifications of the
present invention are possible in the light of the above teaching.
It is therefore to be understood that within the scope of the
appended claims, the present invention may be practiced otherwise
than as specifically described.
* * * * *