Switching apparatus

A movable contact holder includes a rod-shaped portion which is formed in such a manner as to extend in a direction which is at substantially right angles to a traveling direction of a movable unit and is substantially parallel to a sliding plane of a movable contact, and the movable contact includes a folded-back piece portion which is folded back in such a manner as to extend along a circumferential side surface of the rod-shaped portion and is formed in such a manner as to be elastically deformable, whereby when a folded-back side surface of the folded-back piece portion turns around the circumferential side surface of the rod-shaped portion, the movable contact is assembled to the movable contact holder.

BACKGROUND OF THE INVENTION

The present invention relates to a switching apparatus including a movable unit made up of a movable contact and a movable contact holder, the movable contact being assembled to the movable contact holder, and a plurality of stationary contacts arranged along a traveling direction of the movable unit in which grease is applied between the movable contact and the stationary contacts, and the movable contact slides on the plurality of stationary contacts in association with a reciprocating movement of the movable element along a direction in which the movable contact is assembled to the movable contact holder.

A switching apparatus of this type is configured as shown inFIG. 6. A switching apparatus101is configured so as to include a movable unit102and an insulator103. The movable unit102is made up of a movable contact holder104and a movable contact105, the movable contact105being assembled to the movable contact holder104, and is made to reciprocate on the insulator103in directions indicated by arrows B1, B2inFIG. 6. A plurality of stationary contacts106ato106dare arranged on the insulator103along the traveling direction of the movable unit102. A control circuit (not shown) for controlling onboard equipment (not shown) is connected to these stationary contacts106ato106d. Then, in association with a movement of the movable unit102in the directions indicated by the arrows B1, B2inFIG. 6, the movable contact105is designed to slide on the stationary contacts106ato106din the directions indicated by the arrows B1, B2inFIG. 6.

As this occurs, depending upon a position which the movable unit102has reached as a result of its traveling in the directions indicated by the arrows B1, B2inFIG. 6, among the stationary contacts106ato106d, the stationary contacts with which the movable contact105is brought into sliding contact so as to energize are changed over, and the operation of the onboard equipment is designed to be changed over according to the stationary contact that is put in an energized state as a result of energization via the movable contact105(refer to JP-A-2005-078838, for example).

Incidentally, in the switching apparatus101, the movable contact105is inserted into an insertion port104awhich is opened along the traveling direction of the movable unit102and is assembled to the movable contact holder104in such a state that the movable contact105is prevented from being dislodged by raised portions104b. In addition, it is a general practice to apply grease (not shown) as a lubricant between the movable contact105and the stationary contacts106ato106d.

In this configuration, however, there exist the following problems.

While the grease is such as to have a function as a lubricant, in the event that temperature decreases, for example, there may occurs a case where the function as the lubricant is lost. In addition, in the event that the lubricating properties of the grease are lost, there may occur a case where the movable contact105securely sticks to the stationary contacts106ato106dside.

As this occurs, in production of a switching apparatus101, for example, when attempting to remove the movable unit102from the insulator103in order to remount the movable unit102, since there occurs a state where the movable contact105is pulled towards the insulator103side due to the tackiness of the grease, a force acts on the movable contact105in an opposite direction (the direction indicated by the arrow B1inFIG. 6) to the direction in which the movable contact105is assembled to the movable contact holder104. In addition, in a case where the switching apparatus101is actually used as a product, since the traveling direction of the movable unit102substantially coincides with the direction in which the movable contact105is assembled to the movable contact holder104, when the movable unit102is caused to travel in the direction indicated by the arrow B2inFIG. 6, the force acts, in this case, too, on the movable contact105in the opposite direction to the assembling direction of the movable contact105to the movable contact holder104.

In addition, when the switching apparatus101is used for such a long period of time that grease is deteriorated, since there is generated a large frictional force or vibration between the movable contact105and the stationary contacts106ato106dduring the travel of the movable unit102, the force is also made to act on the movable contact105in the opposite direction to the assembling direction of the movable contact105to the movable contact holder104due to the effect of such a large frictional force or vibration.

Due to this, in the configuration described above in which the movable contact105is simply inserted into the insertion port104aof the movable contact holder104so as to be prevented from being dislodged by the raised portions104b, the movable contact105cannot resist the force acting thereon in the opposite direction to the assembling direction of the movable contact105to the movable contact holder104(a force acting in a direction in which the movable contact105is dislodged from the movable contact holder104), resulting in a problem that the movable contact105is removed from the movable contact holder104.

SUMMARY OF THE INVENTION

The invention has been made in view of the situations, and an object thereof is to provide a switching apparatus in which even in the event that the force acts on the movable contact in the opposite direction to the direction in which the movable contact is assembled to the movable contact holder due to the effect of the tackiness of grease or the large frictional force or vibration which is generated when the movable unit slides, the movable contact can hold the movable contact holder in a proper fashion, so as to accomplish an increase in quality.

In order to solve the object, the present invention is characterized by having the following arrangement.(1) A switching apparatus comprising:

a plurality of stationary contacts arranged in a first direction;

a contact holder movable in the first direction, the contact holder including a rod-shaped portion extending in a second direction substantially perpendicular to the first direction and in substantially parallel with a sliding plane of the contact holder;

a movable contact assembled to the contact holder, the movable contact including a elastically deformable folded-back piece portion which is folded back in such a manner as to be wound around a circumferential side surface of the rod-shaped portion, and a sliding piece portion which slides on and contacts the plurality of stationary contacts with the movement of the contact holder; and

grease applied between the sliding piece portion and the plurality of stationary contacts.(2) The switching apparatus according to (1), wherein a cross section of the rod-shaped portion is formed into a circular shape.(3) The switching apparatus according to (1), wherein a cross section of the rod-shaped portion is formed into a quadrangular shape.(4) The switching apparatus according to (1), wherein a cross section of the rod-shaped portion is formed into a triangular shape.(5) The switching apparatus according to (1), wherein

the movable contact includes a bent piece portion which is formed by bending a distal end of the folded-back piece portion in an opposite direction to a direction in which the folded-back piece portion is folded back, and

the bent piece portion is locked on a part of the contact holder so that the movable contact is assembled to the contact holder.

According to the switching apparatus of the first aspect of the invention, since the folded-back side surface of the folded-back piece portion is made to turn around the circumferential side surface of the rod-shaped portion of the movable contact holder, there is caused a state where the folded-back piece portion of the movable contact grabs the rod-shaped portion of the movable contact holder, whereby even in the event that the force acts on the movable contact in the opposite direction to the direction in which the movable contact is assembled to the movable contact holder due to the effect of the tackiness of grease applied between the movable contact and the stationary contacts or the large frictional force or vibration which is generated when the movable contact slides on the stationary contact, being from the conventional example, the movable contact can hold strongly the movable contact holder.

According to the switching apparatus of the second aspect of the invention, since the cross section of the rod-shaped portion which is at substantially right angles to the direction in which the rod-shaped portion extends is made into the circular shape, the circumferential side surface of the rod-shaped portion is formed into a curved surface, so that force can be made to act uniformly on the circumferential side surface of the rod-shaped portion of the movable contact holder from the folded-back side surface of the folded-back piece portion, whereby the movable contact can hold strongly the movable contact holder.

According to the switching apparatus of the third aspect of the invention, since the folded-back piece portion is made to be locked on part of the movable contact bolder, there is generated a state where the movable contact is supported on a locking position where the folded-back piece portion is locked on part of the movable contact holder, whereby the movable contact can be supported at such two locations as the rod-shaped portion of the movable contact holder and the locking position, so that the movable contact can be assembled to the movable contact holder in a stable state.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the invention will be described by reference toFIGS. 1 to 3. InFIG. 3, a switching apparatus1is made up of a case2, a movable unit3and an insulator4.

The case2is formed into a rectangular box shape and a slide groove2ais provided in an upper portion thereof in such a manner as to extend along a longitudinal direction of the case2. The movable unit3is made up of a movable contact holder5and a movable contact6in such a state that the movable contact6is assembled to the movable contact holder5. Details of the movable contact holder5and the movable contact6will be described later on. In addition, the movable unit3is provided in such a manner as to reciprocate in the case2in directions indicated by arrows A1, A1inFIG. 3in such a state that an operation lug5aformed integrally with the movable contact bolder5is inserted in the slide groove2a.

The insulator4is provided at a bottom portion inside the case2. A plurality of stationary contacts7ato7dare arranged on an upper surface4aof the insulator4. Among these stationary contacts7ato7d, the stationary contact7ais formed into an elongated shape in such a manner as to extend along a traveling direction of the movable unit, while the stationary contacts7bto7dare formed intermittently along a direction which is parallel to the stationary contact7a. In addition, a control circuit (not shown) for controlling onboard equipment (not shown) is connected to these stationary contacts7ato7d.

Then, in association with the traveling of the movable unit3in the directions indicated by the arrows A, A2inFIG. 3, a sliding piece portion of the movable contact6is designed to slide on the stationary contact7ain the directions indicated by the arrows A1, A2inFIG. 3, and at the same time as this occurs, a sliding piece portion6bis designed to slide on the stationary contacts7bto7din the directions indicated by the arrows A1, A2inFIG. 3. Note that also in this switching apparatus1, grease (not shown) as a lubricant is applied between the sliding piece portions6a,6bof the movable contact6and the stationary contacts7ato7d.

In addition, the movable unit3is designed to be locked by a click-stop mechanism (not shown) at positions where the sliding piece portion6bis brought into sliding contact with the stationary contacts7bto7d, respectively. As this occurs, depending upon a position where the movable unit3is locked, among the stationary contacts7bto7d, the stationary contacts with which the sliding piece portion6bof the movable contact6is brought into sliding contact for energization together with the stationary contact7aare changed over, and the control circuit is designed to operate the onboard equipment in an operation pattern corresponding to the stationary contact that is put in an energized state as a result of energization via the sliding piece portion6bof the movable contact6. For example, when the stationary contact7aand the stationary contact7bare put in the energized state, the control circuit operates the onboard equipment in a first operation pattern, when the stationary contact7aand the stationary contact7care put in the energized state, the control circuit operates the onboard equipment in a second operation pattern, and when the stationary contact7aand the stationary contact7dare put in the energized state, the control circuit operates the onboard equipment in a third operation pattern.

Next, the movable contact holder5and the movable contact6, which have been described above, will be further described by reference toFIGS. 1 and 2, as well.FIG. 1is an external perspective view which shows external appearances of the movable contact6and the movable contact holder5, andFIG. 2is a side view which shows a state where the movable contact6is assembled to the movable contact holder5with part cut away. Note that inFIGS. 1 and 2, for easy understanding of the description of the relevant portions, the movable unit3is shown with its side where the operation lug5ais provided facing downwards.

Firstly, the shapes of the movable contact holder5and the movable contact6will be described, respectively. As shown inFIG. 1, a bottom surface5bof the movable contact holder5is formed in such a manner as to be substantially parallel to a sliding plane (in other words, the upper surface4aof the insulator4) where the movable contact6slides on the stationary contacts7ato7d. In addition, a rod-shaped portion8, a beam portion9and lug portions10a,10bare provided on the movable contact holder5. The rod-shaped portion8is formed in such a manner as to extend in a direction which is at substantially right angles to directions indicated by arrows A1, A2inFIG. 1along which the movable unit3travels is substantially parallel to the bottom surface5b(in other words, the sliding plane of the movable contact6). In addition, a cross section (refer to FIG.2)of the rod-shaped portion8which is at substantially right angles to the extending direction thereof is formed into a circular shape. Namely, a circumferential side surface8aof the rod-shaped portion is formed into a curved surface. The beam portion9is formed in such a manner as to extend along the rod-shaped portion8.

On the other hand, in addition to the aforesaid sliding piece portions6a,6b, a flat plane portion11, a folded-back piece portion12and a bent piece portion13are provided on the movable contact6. The flat plane portion11is formed into a flat plane shape which extends from a root portion of the sliding piece portions6a,6btowards the direction indicated by the arrow A2inFIG. 1. A length L1of the flat plane portion11in the directions indicated by the arrows A1, A2inFIG. 1is made substantially equal to a length L2which extends from a root portion of the lug portions10a,10bto the rod-shaped portion8on the movable contact holder5in the directions indicated by the arrows A1, A2inFIG. 1. The folded-back piece portion12is such as to be folded back so as to extend along the circumferential side surface8aof the rod-shaped portion8when the movable contact6is assembled to the movable contact holder5and is formed in such a manner as to be elastically deformable. The bent piece portion13is formed by bending a distal end of the folded-back piece portion12in an opposite direction to the direction in which the folded-back piece portion12is folded back.

Next, a state where the movable contact6is assembled will be described. When the movable contact6is caused to travel in the direction indicated by the arrow A1inFIG. 1with respect to the movable contact holder5, the bent piece portion13of the movable contact6is brought into abutment with the circumferential side surface8aof the rod-shaped portion8. When the movable contact6is caused to travel further in the direction indicated by the arrow A1inFIG. 1from this state, since the folded-back piece portion12is formed in such a manner as to be elastically deformable, a folded-back side surface12aof the folded-back piece portion12fits on the rod-shaped portion8while being forcibly expanded in a smooth fashion as it travels along the curved surface shape of the circumferential side surface8aof the rod-shaped portion8. Then, the folded-back side surface12aof the folded-back piece portion12eventually turns around the circumferential side surface8aof the rod-shaped portion8, as shown inFIG. 2. In addition, the bent piece portion13is locked on the beam portion9which is part of the movable contact holder5. As this occurs, since the length L1of the movable contact6side and the length L2of the movable contact holder5side are made substantially equal to each other, an end portion11aof the flat plane portion11of the movable contact6is hooked at the lug portions10a,10bon the movable contact holder5

Next, as to the switching apparatus1that is configured as described above, a case is assumed where the lubricating properties of the grease are lost and the sliding piece portions6a,6bof the movable contact6are securely stuck to the stationary contacts7ato7dside.

In this case, in producing a switching apparatus1, for example, when attempting to remove the movable unit3from the insulator4in order to remount the movable unit3, since a state results where the movable contact6is pulled to the insulator4side due to the tackiness of the grease, a force acts on the movable contact6in an opposite direction (the direction indicated by the arrow A2inFIG. 3) to the direction in which the movable contact6is assembled to the movable contact holder5. In addition, in a case where the switching apparatus1is actually used as a product, since the traveling direction of the movable unit3substantially coincides with the assembling direction of the movable contact6onto the movable contact holder5, when the movable unit3is caused to travel in the direction indicated by the arrow A1inFIG. 3, a force acts on the movable contact6in the opposite direction to the assembling direction of the movable contact6onto the movable contact holder5due to the tackiness of the grease.

In addition, assuming a case where the switching apparatus1is used for such a long period of time that the grease is deteriorated, a force acts on the movable contact6in the opposite direction to the direction in which the movable contact6is assembled to the movable contact holder5due to the effect of a large frictional force or vibration generated between the sliding piece portions6a,6band the stationary contacts7ato7dwhen the movable unit3travels.

With the switching apparatus1of the invention, however, since the folded-back side surface12aof the folded-back piece portion12is made to turn around the circumferential side surface8aof the rod-shaped portion8of the movable contact holder5, a state results where the folded-back piece portion12of the movable contact6grabs the rod-shaped portion8of the movable contact holder5. Consequently, even in the event that the force acts on the movable contact6in the opposite direction to the direction in which the movable contact6is assembled to the movable contact holder5, the movable contact6holds the movable contact holder5in such a manner that the folded-back piece portion12grabs the rod-shaped portion. In addition, since the circumferential side surface8aof the rod-shaped portion8is formed into the curved surface shape, the folded-back side surface12aof the folded-back piece portion12allows force to be applied uniformly to the circumferential side surface8aof the rod-shaped portion8of the movable contact holder5.

Furthermore, since the bent piece portion13is made to be locked on the beam portion9, a state results where the movable contact6is supported at a locking position where the bent piece portion13is locked on the beam portion9.

While the case has been described heretofore where the force acts on the movable contact6in the opposite direction to the direction in which the movable contact6is assembled to the movable contact holder5, there may exist a case where due to the effect of the force acting in this direction, a force also acts on the movable contact6in another direction (for example, a direction perpendicular to the direction in which the movable contact6is assembled to the movable contact holder5). With the switching apparatus1of the invention, however, since the end portion11aof the flat plane portion11is caught at the lug portions10a,10b, even in the event that the force acts on the movable contact6in the direction perpendicular to the direction in which the movable contact6is assembled to the movable contact holder5, the flat plane portion11is held to the bottom surface5bside by the lug portions10a,10b.

As has been described heretofore, according to the embodiment of the invention, since the folded-back side surface12aof the folded-back piece portion12is made to turn around the circumferential side surface8aof the rod-shaped portion8on the movable contact holder5, the state results where the folded-back piece portion12of the movable contact6grabs the rod-shaped portion8of the movable contact holder5, whereby even in the event that the force acts on the movable contact6in the opposite direction to the direction in which the movable contact6is assembled to the movable contact holder5due to the tackiness of the grease applied between the movable contact6and the stationary contacts7ato7dor the effect of the large frictional force or vibration generated when the movable contact6slides on the stationary contacts7ato7d, being different from the conventional examples, the movable contact6can hold the movable contact holder5in a proper fashion, thereby making it possible to accomplish an increase in quality.

In addition, since the cross section of the rod-shaped portion8which is at substantially right angles to the direction in which the rod-shaped portion8extends is formed into the circular shape, the circumferential side surface8aof the rod-shaped portion8is formed into the curved surface shape, the force can be applied uniformly from the folded-back side surface12aof the folded-back piece portion12to the circumferential side surface8aof the rod-shaped portion8of the movable contact holder5, thereby making it possible that the movable contact6can hold strongly the movable contact holder5. In addition, when assembling the movable contact6to the movable holder5, since the folded-back piece portion12is forcibly expanded in a smooth fashion along the circumferential side surface8aof the rod-shaped portion8, the assembly of the movable contact6can be facilitated.

Additionally, since the bent piece portion13is made to be locked on the beam portion9which makes up part of the movable contact holder5, the state results where the movable contact6is supported at the locking position between the bent piece portion13and the beam portion9, whereby the movable contact6can be supported at two locations, the rod-shaped portion8and the beam portion9, on the movable contact holder5, thereby making it possible to assemble the movable contact6to the movable contact holder5in a stable state.

In addition, even in the event that the force acts on the movable contact6in the direction perpendicular to the direction in which the movable contact6is assembled to the movable contact holder5, since the flat plane portion11is held to the bottom surface5bside by the lug portions10a,10b, the expansion of the folded-back piece portion12can be prevented which would otherwise be generated due to the flat plane portion11of the movable contact6warping up from the bottom surface5bof the movable contact holder5, whereby the holding force of the movable contact6is weakened in no case.

The invention is not limited only to the embodiment that has been described heretofore and hence can be modified or expanded in the following manner.

The cross section of the rod-shaped portion is not limited to such a circular shape as one described with respect to the rod-shaped portion8, and as shown inFIG. 4, a configuration may be adopted in which a cross section of a rod-shaped portion22of a movable contact holder21is formed into a quadrangular shape and a folded-back piece portion24of a movable contact23is folded back into a quadrangular shape in such a manner as to follow a circumferential side surface22aof the rod-shaped portion22and is formed in such a manner as to be elastically deformable.

In addition, as shown inFIG. 5, a configuration may be adopted in which a cross section of a rod-shaped portion32of a movable contact holder31is formed into a triangular shape and a folded-back piece portion34of a movable contact33is folded back into a triangular shape in such a manner as to follow a circumferential side surface32aof the rod-shaped portion32and is formed in such a manner as to be elastically deformable. Furthermore, although not shown, the shape of the cross section of the rod-shape portion and the shape into which the folded-back piece portion is folded back may be of other shapes.

The movable unit3is not limited to such as to travel rectilinearly, and hence a movable unit may be adopted which rotates in a arc-like shape.

As onboard equipment to which the switching apparatus1of the invention can be applied, an automotive wiping system can be raised, for example. In this event, the movable unit3may only have to be designed to travel according to a position to which an operation stalk of an automotive wiper switch. In addition, the switching apparatus of the invention can also be applied to a turn signal switch or an automatic transmission switch, and in this event, the movable unit3may only have to be designed to travel while interlocking with an operating element of each of the onboard equipment.