Electricity: circuit makers and breakers – Special application
Reexamination Certificate
2000-02-09
2002-01-29
Bradley, Paula (Department: 2832)
Electricity: circuit makers and breakers
Special application
C439S188000
Reexamination Certificate
active
06342684
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application relates to and claims priority, under 35 U.S.C. §119, from Japanese Patent Application No. 11-206773 filed on Jul. 21, 1999, the entire contents of which are hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a device for detecting objects which have been transferred to operate a switch. The device has a contact which comes into contact with a set position (for example, a terminal) of a different kinds of objects, such as a digital video cassette (DVC) and all other types of cassette, a FD and all other types of discs, and so on. The objects have been transferred to operate a switch and thereby, perform different electrical detecting operations. More particularly, the present invention provides a device for detecting objects which have been transferred to operate a switch, wherein the device includes a flexible spring part formed between a mounting plate part and a U-shaped spring part in a contact spring piece, made of a plate spring. The device further includes the mounting plate part, the U-shaped spring part, and a contact part so as to allow for making the spring span longer to equalize, with high precision, the required load for the contact spring piece (i.e., the contact pressure of the contact with the object) and at the same time, to drastically improve the durability of the contact spring piece.
2. Discussion of Background
A device for detecting an object transferred to operate a switch has been conventionally used, wherein a set position of the transferred object, such as a DVC, other types of cassettes, etc., comes into contact with a contact of a contact spring piece to operate the switch, thereby performing different electrical detecting operations. Two kinds of devices have been used for detecting the object transferred to operate the switch, namely, one in which a contact spring piece is made of wire, and another in which a contact spring piece is made of a narrow and long plate spring piece.
The device for detecting an object, which has been transferred to operate a switch and which uses the contact spring piece made of wire as described above, is prepared, for example, as shown in FIG.
9
. Referring to
FIG. 9
, a coil part
108
is shown as being elongatedly attached to the top of an upright mounting part
101
. A contact spring piece A
1
is elongatedly equipped with an angled contact part
103
. The angled contact part
103
is the lower part of the contact spring piece A
1
. An upright mounting part
101
is inserted into a hole or slit
106
of a back plate
105
of an L-shaped insulating stock
104
and is fixed in the hole of slit
106
. A lower end of the upright mounting part
101
extends outwardly past a lower end of a base
107
of the L-shaped insulating stock
104
to form a terminal
101
a
. A shaft
111
is inserted into the coil part
108
. The angled contact part
103
extends outwardly in front of the back plate
105
of the L-shaped insulating stock
104
. A lower end of the angled contact part
103
presses against the front end of a slit
110
of the base
107
of the L-shaped insulating stock
104
.
Referring to
FIG. 9
, an object
109
is shown as being moved in a downward direction so as to contact an upper part of the angled contact part
103
. Once contact between the object
109
and the angled contact part
103
is established, the object
109
is then continued to be moved downwardly towards a contact or top
103
a
of the angled contact part
103
, while being in contact with the angled contact part
103
. The contact between the object
109
and the angled contact part
103
creates a downwardly-directed load L
1
and a cross-direction load L
2
on the angled contact part
103
. The downwardly-directed load L
1
, which moves the angled contact part
103
downwardly towards the bottom surface of the L-shaped insulating stock
104
, is added to the cross-direction load L
2
, which moves the angled contact part
103
backwardly in the direction of the front surface of the back plate
105
. The downwardly-directed load L
1
and cross-direction load L
2
act as a force for winding a coil of the coil part
108
so that a set position or terminal (not shown) of the object
109
contacts the contact or top
103
a
of the angled contact part
103
. A bending load P
5
is applied to the upper part of the contact spring piece A
1
to compress and bend the angled contact part
103
of the contact spring piece A
1
and the coil part
108
in cross-direction so as to operate the switch in order to perform detection of the object
109
.
However, the detecting device of
FIG. 9
has disadvantages with respect to the contact spring piece A
1
which is made of wire and these disadvantages will be described in more detail, as follows:
(1). Since the coil part
108
is formed by three or four circular windings forming a coil, a certain amount of space is required, i.e., enough space for a shaft
111
of a predetermined diameter and for the width of the three or four circular windings of the coil. Therefore, further miniaturization of the detecting device is made more difficult to accomplish.
(2). Uniform and precise fabrication is not feasible because of the wire making up the contact spring piece A
1
. In other word, scatter occurs in every contact spring piece A
1
, particularly, in the spring constant.
(3). Since a shaft
111
should be inserted within the three or four windings of the coil of the coil part
108
, the efficiency of the assembly is poor.
(4). Gold-plating of the angled contact part
103
is necessary, but it is not possible to gold-plate only the angled contact part
103
of the contact spring piece A
1
because the wire material making up the contact spring piece is long and continuous and therefore, the overall length of the wire must be gold-plated with expensive gold, so that material costs are raised approximately two to three times what they would be if only the angled contact part
103
of the contact spring piece A
1
had to be gold-plated.
The disadvantage described in (4) above is the most significant disadvantage.
In spite of having the above-described disadvantages, a contact spring piece A
1
made of wire has the advantage of being very durable because the number of windings of the coil of the coil part
108
and the width of the coil can be adjusted.
A contact spring piece A
2
can be made of, for example, a long and narrow plate spring. Such a contact spring piece A
2
is shown in
FIGS. 10 and 11
. This type of contact spring piece A
2
is coming into wider use as compensating for the disadvantages (1)-(4) of the above-described conventional contact spring piece made of wire.
However, it has become clear that the contact spring piece A
2
made of a long and narrow plate spring is fatally poor in durability. A contact spring piece must have sufficient durability when it is subjected to a required load (i.e., contact pressure of the contact with an object). Thus, durability is the most important aspect of a contact spring piece.
This is true because it is the entire upright mounting plate part
101
(i.e., substantially up to a base of the U-shaped spring part
102
as shown in
FIG. 10
) that is inserted into the hole or slit
106
of the back plate
105
of the L-shaped insulating stock
104
and fixed to be immovable therein, when the contact spring piece A
2
is mounted. The contact spring piece A
2
includes the U-shaped spring part
102
and the angled contact part
103
. The U-shaped spring part
102
is attached to the upper end of the upright mounting plate part
101
. The angled contact part
103
is elongatedly attached to the lower part of the U-shaped spring part
102
. Referring to FIGS.
11
(
a
) and
11
(
b
), the U-shaped spring part
102
is shown as having a greater width than the contact spring part
103
, but a smaller width than the mounting plate part
101
.
Referring again to
FIG. 10
, an obliquely downward load P
1
is shown as acting on the upp
Mitsuku Denshi Kogyo K. K.
Nguyen Nhung
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