Buckles – buttons – clasps – etc. – Trim molding fastener – Plastic type
Reexamination Certificate
1999-08-23
2001-10-02
Brittain, James R. (Department: 3626)
Buckles, buttons, clasps, etc.
Trim molding fastener
Plastic type
C024S458000
Reexamination Certificate
active
06295701
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a securing hook for mounting and fixing a member to be secured such as a printed circuit board, a case cover part, or the like, which is equipped in an electric appliance, at a given position within the main body of the electric appliance.
2. Description of the Related Prior Art
In an electric appliance, it is necessary that a printed circuit board with an integrated circuit and electric elements mounted thereon is mounted and fixed at a given position within the main body of the electric appliance. As a fixing structure used to mount such printed circuit board, for example, there are available a fixing structure of a type that there are opened up in a printed circuit board through holes through which screws for fixing the printed circuit board can be inserted, and the printed circuit board is screwed onto bosses provided in the main body of the electric appliance by inserting such screws through the through holes; and, a fixing structure which uses special metal members developed specially for fixing such printed circuit board. Also, there is widely used a method for fixing a printed circuit board using a securing hook molded of resin, because this method allows the printed circuit board to be fixed easily and is advantageous in the cost of parts required.
Here,
FIGS. 4A-4B
,
5
A-
5
C and
6
respectively show a conventional securing hook which is formed of resin material. In particular,
FIG. 4A
is a perspective view of a securing block
300
which is formed of resin material according to an outsert molding method or the like for use in a metal chassis (not shown) or the like. And,
FIG. 4B
is a perspective view of the securing block
300
and a member to be secured
400
such as a printed circuit board or the like, showing a state thereof in which the member to be secured
400
is mounted on and fixed to the securing block
300
.
Also,
FIGS. 5A
to
5
C respectively show a process for mounting and fixing the member to be secured
400
onto the securing block
300
, using a section view taken along the line A—A shown in FIG.
4
A. Further,
FIG. 6
shows a state in which a force to remove the member to be secured
400
from the securing block
300
is applied to the member to be secured
400
fixed to the securing block
300
.
Now, description will be given below in detail of the structure of the conventional securing hook with reference to
FIGS. 4A
,
4
B,
5
A-
5
C and
6
.
The securing block
300
comprises a receive part
320
on which the member to be secured
400
is to be placed, and a securing hook body
310
which is used to fix the member to be secured
400
onto the receive part
320
, while the receive part
320
and securing hook body
310
are formed of resin material as an integrally united body. By the way, the illustrated receive part
320
is formed in a plane shape. And, conventionally, there is also known a method in which, on the plane of the receive part
320
, a positioning projection is formed of the same resin material as the receive part
320
; and, in the member to be secured
400
, there is formed a hole which can be engaged with the positioning projection, whereby the member to be secured
400
can be positioned when mounting and fixing the member to be secured
400
.
The securing hook body
310
is composed of a straight portion
311
which extends upwardly in a substantially straight manner, and a hook portion
312
which is disposed in the leading end portion of the straight portion
311
. And, in the hook portion
312
, there are formed a linear-shaped sliding contact surface
313
which is located on the side of the hook portion
312
where the member to be secured can be secured and also which is inclined downward at a given angle in a direction to move away from the straight portion
311
and, a securing portion
314
which can be engaged with the upper surface of the member to be secured
400
placed on the receive part
320
to thereby fix the member to be secured
400
onto the receive part
320
. The securing portion
314
is so formed as to have a surface substantially parallel to the upper surface of the receive part
320
(that is, a surface intersecting substantially at right angles to the extending direction of the straight portion
311
).
Now, description will be given below in detail of a process in which the member to be secured
400
such as a printed circuit board or the like is pushed into the above-structured securing block
300
by an assembler and is then fixed onto the receive part
320
, with reference to
FIGS. 5A
to
5
C.
Specifically,
FIG. 5A
shows a state in which, in order to fix the member to be secured
400
onto the securing block
300
, the assembler has brought part of one of the sides of the member to be secured
400
into contact with a given position (P
1
) of the sliding surface
313
of the hook portion
312
. In this state, when the assembler tries to push down the member to be secured
400
toward the receive part
320
, the member to be secured
400
is pushed at a pressure angle (&agr;1) that can be determined by the angle of inclination of the sliding contact surface
313
with respect to a direction in which the member to be secured
400
is pushed.
And, when the assembler, while keeping part of one side of the member to be secured
400
in sliding contact with the sliding contact surface
313
, pushes down the member to be secured
400
in the direction of the receive part
320
to thereby move the member to be secured
400
down to a second position (P
2
) which, as shown in FIG.
5
(
b
) , is present on the sliding contact surface
313
and is located downwardly of the given position (P
1
) , due to the action of the pushing force, the straight portion
311
of the securing hook body
310
is flexed in a direction where it moves apart from the receive part
320
(in
FIG. 5B
, in the right direction). In this operation, as the straight portion
311
is flexed, there is generated a flexure angle to thereby change the inclination angle of the sliding contact surface
313
with respect to the pushing direction of the member to be secured
400
. Accordingly, as shown in
FIG. 5B
, a pressure angle (&agr;2) at the position (P
2
) becomes greater than the pressure angle (&agr;1) at the position (P
1
).
Now, description will be given below in detail of the variations in the pressure angle with reference to FIG.
7
.
That is, in
FIG. 7
, in a state where a member A having a length of
1
and having the same cross section is held in a cantilever manner with one end al thereof fixed, assuming that the free end a
2
of the member A is moved by a distance of &dgr; by applying a force p to the free end a
2
, the relation shown in the following equation holds (E: modulus of longitudinal elasticity, I: Section secondary moment).
&dgr;=
p
1
3
/3
EI
&thgr;=
P
1
2
/2
EI
From the above relation equation, the variation amount of the flexure angle &thgr; of the member A can be expressed by the following equation:
&thgr;=(3/2
I
)&dgr;.
Therefore, when taking the above relation into consideration, as shown in
FIGS. 5A and 5B
, according as the sliding contact position between the member to be secured
400
and sliding contact surface
313
varies as a result of the member to be secured
400
being pushed and moved, the straight portion
311
increases in the flexure amount &dgr; gradually. With the increase in the flexure amount &dgr;, the flexure angle also increases. And, as the flexure angle increases, the pressure angle also increases. Let us express the variations of the sliding contact position between the two elements in a numerical manner. That is, if the initial pressure angle at the position (P
1
) is expressed as (&agr;1), then the pressure angle (&agr;2) at the position (P
2
), namely, the flexure amount &dgr; can be expressed as follows:
(&agr;2)=(&agr;1)+(3/2
I
)&dgr;
When the assembler has pushed the member to be secured
400
down to a position where the member to be secure
Brittain James R.
Pioneer Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
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