Spacer for mounting boards

A spacer for mounting boards, such as wiring boards or printed circuit boards, made of synthetic resin and comprising a resilient detent member provided at one end of a center support pillar member which extends in the vertical direction from the center of the resilient detent member, a pair of resilient reverse detent leg members provided at both sides of the support pillar member and extending obliquely downward so as to prevent the spacer from coming off out of the board or boards when inserted through a hole formed in one of the boards and mounted on the boards by restoring its inherently extended condition of the leg members, and a resilient support member provided at the other end of the support pillar member, all which components are integrally formed in one piece. With this construction, the spacer can be easily mounted at one of the boards so as to hold the boards and maintain a space between the boards without bending, even if it is mounted on the wiring boards carrying heavy electronic parts thereon. The spacer is simple in construction and is easy for manufacturing at low cost.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a spacer made of synthetic resin and for 
maintaining space between base plates or boards such as wiring boards or 
printed circuit boards by inserting into a mounting hole formed on one of 
the boards and fixing said boards when using a plurality of the boards in 
a stacked condition. 
2. Description of the Prior Art 
When mounting many wiring boards, for instance, on a chassis of an 
electronic apparatus or appliance according to the prior art, it is often 
desired that each board is stacked in the horizontal direction at a 
predetermined distance, with one edge of each board coupled on a frame 
through hinge means. 
In this case, however, when rather heavy electronic parts are mounted on a 
wiring board such as is mentioned above, the board often becomes flexed 
downward, thus causing short circuited conditions to occur on the board or 
damages to the board to occur. 
In order to prevent these short circuited conditions and damages to the 
board or boards from occurring, conventionally spacers are inserted 
between wiring boards. However, the spacers of this kind according to the 
prior art are used in such a manner that they are only sandwiched between 
the upper and lower boards, thus resulting in shortcomings such as that 
the spacers often come off by vibrations caused for some reasons or by 
accidental shocks when carrying out, for instance, maintenance work. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a spacer for 
mounting boards, which is capable of easily inserting into a mounting hole 
formed on one of the boards and which is capable of holding, with 
resiliency, two boards such as upper and lower boards at a predetermined 
distance. 
It is another object of the present invention to provide a spacer with a 
simple construction and capable of manufacturing at a low cost. 
One of the features according to the present invention resides in a spacer 
made of synthetic resin and which can be mounted between boards such as 
wiring boards through a mounting hole formed in the board or boards by the 
insertion of part of the spacer wherein it comprises a dish-shaped 
resilient detent member provided at one end of a support pillar member, 
said support pillar member extending in the vertical direction from the 
center of the dish-shaped resilient detent member, a pair of resilient 
reverse detent leg members provided at both sides of the support pillar 
member and extending obliquely downward so as to prevent the spacer from 
coming off out of the board or boards when inserted through a hole and 
mounted on the boards by restoring its inherently extended condition of 
the resilient leg members, and a dish-shaped support member provided at 
the other end of said support pillar member, all the constructing 
components described above being integrally formed in one piece. 
These and other objects, features, and advantages of the present invention 
will be apparent from the following detailed description with reference to 
the attached drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The reader's attention is first referred to FIG. 1, where an overall 
perspective view of the spacer according to the present invention is 
shown. The spacer according to the present invention comprises a first 
dish-shaped resilient detent member 1, a support pillar member 2 extending 
in the vertical direction from the center of the first dish-shaped 
resilient detent member, a pair of resilient reverse detent leg members 3, 
3, and a second dish-shaped resilient support member 4 for supporting one 
of the wiring boards, the top or upper portion of the second dish-shaped 
resilient support member 4 having a concave shape or a "cupule" shape. The 
second dish-shaped resilient support member 4 is smaller in diameter than 
the first dish-shaped resilient support member 1. All the components 
described above of the spacer according to the present invention are 
integrally formed in one piece made, for instance, of synthetic resin. 
FIGS. 2 and 3 show, respectively, an enlarged top view and an elevational 
view of the spacer of the present invention shown in FIG. 1. The spacer 
for mounting boards according to the present invention is made of 
synthetic resin, for instance, 66 nylon, and it is integrally formed in 
one piece as more clearly shown in FIG. 4, so as to have resiliency. 
As shown in FIG. 4, the support pillar member 2 has a generally rectangular 
cross section and is formed on the center of the first dish-shaped 
resilient detent member 1 on its upper side and extends in the vertical 
direction therefrom. The resilient reverse detent leg members 3, 3 extend 
obliquely downwardly from the upper end of the support pillar member 2 so 
as to increase the distance between the leg members 3, 3 toward the 
downward direction. Each cross section of the leg members has an arc shape 
on the outer side as shown in FIG. 9. The leg members 3, 3 have a 
sufficient resiliency against the support pillar member 2 so as to be 
resiliently flexible at the lower end thereof in either opening or closing 
direction. 
At the bottom surface of each resilient reverse detent leg member 3, there 
are provided respectively a horizontal notch portion 3a and a projection 
or an engagement member 3b which in combination form a stepped portion and 
which support one of the boards from the inner side of the one wiring 
board to be fixed, so as to engage with the inner side of a hole formed on 
the board. As shown in FIG. 4, the extreme end of each stepped portion of 
the engagement member 3b slightly enters into the recess of the 
dish-shaped resilient detent member 1. Moreover, the horizontal notch 
portion 3a of each resilient reverse detent leg member 3 securely contacts 
with the surface of the board to be mounted when mounting the spacer 
around the mounting hole. In the spacer according to the present 
invention, a bay-shaped spaced portion R (shown in FIG. 4) is formed at 
the root of the each resilient reverse detent leg member 3 so as to easily 
cause the leg member to be resiliently deformed in the right and left 
direction in the drawing. 
FIG. 5 shows a side view of the spacer having the resilient reverse detent 
leg member 3. The width of the leg member 3 is smaller than that of the 
central support pillar member 2 having the neck portion 2a. FIG. 8 shows 
the cross-section of the neck portion 2a of the support pillar member 2. 
It is to be understood that it has generally an elliptical cross section. 
Turning back to FIG. 4, at the top of the support pillar member 2 having 
the neck portion 2a, there is horizontally formed the second dish-shaped 
resilient support member 4 having the hollow cupule directed upwardly, so 
as to resiliently support one wiring board. 
FIG. 7 shows a cross sectional view of the spacer cut along the line 
VII--VII in FIG. 3 and viewed toward the upper portion of the spacer so as 
to indicate each positional relationship. The spacers for mounting boards 
according to the present invention thus constructed are used, for 
instance, for mounting wiring boards on a chassis of an electronic 
apparatus, secured or fixed by a plurality of mounting supports and bolts 
and nuts, stacking the boards at a predetermined distance. 
FIG. 10 shows a cross sectional view of the spacer according to the present 
invention mounted between the two wiring boards, 5a, 5b, through a 
mounting hole 6 formed in one of the boards, i.e., the lower board 5a in 
this case, with the second dish-shaped resilient support member 4 
supporting the other board 5b. 
When mounting the spacer to the boards, the second dish-shaped resilient 
support member 4 is firstly pushed into the hole 6 formed on the lower 
board 5a, with both resilient reverse detent leg members 3, 3 being 
deformed as indicated by the dot-dashed line or a chain line, until the 
edge of the resilient detent member 1 contacts with the outer surface of 
the board 5a. In this case, the diameter of the mounting hole 6 is formed 
in such a manner that when both horizontal notch portions 3a of the spacer 
have penetrated through the hole 6 and the pair of the resilient reverse 
detent leg members 3, 3 have returned to their normal positions after 
passing through the hole 6, the stepped portions consisting of the 
horizontal notch portions 3a and the engagement members 3b come to engage 
with the edge of the hole 6. Thus, the stepped portions tightly hold the 
inner wall of the hole 6 and the periphery of the inner surface of the 
board 5a around the hole. 
Accordingly, a further pushing operation of the resilient detent member 1 
(i.e., of the bottom thereof by hand) enables the resilient detent member 
1 to be deformed flatly, so that the whole portion of the spacer except 
for the first dish-shaped resilient detent member 1 can completely 
penetrate through the hole 6, and each horizontal notch portion 3a of the 
leg members 3 projects from the hole 6 and engages with the inner surface 
of the board 5a around the hole. As a result, the engagement member 3b and 
the horizontal notch portion 3a grasp the inner wall of the hole 6 and the 
inner surface of the board 5a, around the hole 6 after the resiliency of 
the leg members 3, 3 has restored nearly their original shape. 
In this manner as described, the spacer according to the present invention 
can be securely fixed on boards such as wiring boards, and it can securely 
maintain the space between the two boards by the first dish-shaped 
resiliency of the resilient detent member 1 and the resilient reverse 
detent leg members 3, 3 through the hole 6 formed on one board 5a without 
losing its resiliency and backlash. 
Moreover in the spacer according to the present invention, since the second 
dish-shaped resilient support member 4 can be also deformed on the inner 
surface of the other board 5b when pushed into the hole and contacted with 
the inner surface thereof, the spacer can favorably support the boards and 
secure a space between the boards with its resiliency. 
In the foregoing embodiment, the second dish-shape resilient support member 
4 can have a variety of shapes. Accordingly, the dish-shaped resilient 
support member 4 is not limited to a circular shape only. It can be formed 
like the embodiments shown in FIGS. 11 and 12. Specifically, FIG. 11 shows 
a second resilient support member in the shape of a segment of a 
cylindrical pipe, and FIG. 12 shows a second resilient support member 
formed from a plurality of planar segments angled relative to one another. 
The first resilient detent member 1 is also not limited to the form as 
described. For instance, it can have a rectangular flat form. 
As described in the foregoing, the spacer for mounting boards according to 
the present invention is characterized in that it comprises a dish-shaped 
resilient detent member provided at one end of a support pillar member, 
said support pillar member extending in the vertical direction from the 
center of the dish-shaped resilient detent member, a pair of resilient 
reverse detent leg members provided at both sides of the support pillar 
member and extending obliquely downwardly so as to prevent the spacer from 
coming off out of the board or boards when inserted through a hole and 
mounted on the boards by restoring its inherently extended condition of 
the resilient leg members, and a dish-shaped resilient support member 
provided at the other end of said support pillar member. All of the 
constructing elements or components are integrally formed in one piece. 
Accordingly, the spacer according to the present invention can be easily 
inserted into a mounting hole formed on a board, it can resiliently hold 
the boards and maintain a space between the boards without bending even if 
it is mounted on the wiring boards carrying heavy electronic elements for 
an electronic apparatus or appliance. 
Moreover, since the spacer according to the present invention is made of 
synthetic resin and is integrally formed in one piece, it has a high 
rigidity with a simple construction, as well as being easy for 
manufacturing at low cost. 
While the invention has been described in its preferred embodiment, it is 
to be understood that the words which have been used are words of 
description rather than limitation and that various changes and 
modifications can be made within the purview of the appended claims 
without departing from the true scope and spirit of the invention in its 
broader aspects.