SUN, Chang Lin (Room 2102, Unit 1 Building 14,ChuangXinYuan, Changping district, Beijing 0, 10220, CN)
SHI, Zhi Jie (Room703, Building3# Ziweitianyue apartment,Xiaoying North Road, YaYunCun,Chaoyang, Beijing 1, 10010, CN)
BU, Yong (NO.178 YuHuaYuan, YiHeShangZhuangXiBeiWang, HaiDian district, Beijing 5, 10009, CN)
SUN, Chang Lin (Room 2102, Unit 1 Building 14,ChuangXinYuan, Changping district, Beijing 0, 10220, CN)
SHI, Zhi Jie (Room703, Building3# Ziweitianyue apartment,Xiaoying North Road, YaYunCun,Chaoyang, Beijing 1, 10010, CN)
| Claims 1. A micro-switch, comprising: an operating element (40) which can be operated to realize the on or off state of the micro-switch; a circuit board assembly (20) with a switch unit (24) thereon; and a contact element (46), wherein said contact element (46) comprises: a fixed portion (462) connected to said operating element (40); and a U-shaped contact portion (464), wherein one arm of the U-shaped contact portion (464) can be in contact with or separated from said switch unit (24) so as to realize the on or off state of the micro-switch. 2. The micro-switch as claimed in claim 1, wherein said contact element (46) is detachably connected to said operating element (40) via said fixed portion (462) . 3. The micro-switch as claimed in claim 1 or 2, wherein said contact element (46) is a metal one. 4. A manual alarm device, wherein it comprises: a housing, and a trigger mechanism for manually triggering said manual alarm device in case of making an alarm; wherein said trigger mechanism is moveably disposed in said housing and includes a micro-switch as claimed in any of the preceding claims for indicating an alarm by pressing an operating element (40) of said micro-switch. |
Micro-Switch and Manual Alarm Device Technical Field
The present invention relates to a micro-switch and, especially, to a micro-switch with a relatively large
operating tolerance, and the present invention further relates to a manual alarm device having such a micro-switch for indicating an alarm by pressing an operating element.
Background art
A micro-switch is a fast switch activated by pressing, also referred to as a sensitive switch, after an external mechanical force has been exerted as a force on an action spring leaf via a transmission element and the energy has accumulated to a critical point, it would generate an
instantaneous motion and enable a moving contact point at the end of the action spring leaf to quickly contact a stationary contact point or separate it therefrom, thus realizing the on and off states of the switch.
Currently, the micro-switches are widely used in various technical fields due to their high sensitivities, and a large number of micro-switches have been used in TVs, computers, as well as aircrafts. The micro-switches are also used in some existing devices, such as manual alarm points (MCPs) , and such a micro-switch includes an operating element and a circuit board assembly which is also provided with a switch unit thereon, however, due to the limited space, the on and off states of the switch unit are usually realized by keeping the operating element in direct contact with the switch unit. However, such a contact would provide a small tolerance to the operation of the switch unit, thereby bringing about some problems. On the one hand, it would result in relatively high requirements to the precision of the components; on the other hand, the switch unit and/or the circuit board assembly would often be damaged if the force exerted by an operator using it is too large.
Contents of the invention
An object of the present invention is to provide a micro-switch which has a large operating tolerance and can be operated safely. Another object of the present invention is to provide an improved manual alarm device. The present invention provides a micro-switch,
comprising an operating element which can be operated to realize the on or off state of the micro-switch, a circuit board assembly with a switch unit thereon, and a contact element. The contact element includes a fixed portion
connected to the operating element; and a U-shaped contact portion, with one arm of the contact portion U being able to contact with or to separate from said switch unit so as to realize the on or off state of the micro-switch. In another particular embodiment of the present
invention, the contact element is detachably connected to the operating element via a fixed portion.
In yet another particular embodiment of the present invention, the contact element is made of an elastic metal material .
Since the contact element in the micro-switch has a U- shaped contact portion, when the force exerted on the
operating element is too large that the moving journey of the operating element is too long and exceeds the limit of the journey of the contact element, the arms of the U shape can be deformed due to the squeezing during the contact process of the switch unit, so as to realize an over-force
compensation. The U-shaped contact portion provides a larger operating tolerance for the micro-switch and prevents the switch unit and/or circuit board assembly from being damaged due to over-stress, thus making the micro-switch of the present invention safer when being used. Furthermore, such a design also lowers the requirements to the precision of the components to a certain extent. In the micro-switch of the present invention, the fixed portion of the contact element is detachably connected to the operating element by way of engagement, etc., and when the contact element fails, it only needs to remove the contact element from the operating element and replace it with a new one, without replacing the whole micro-switch, thus reducing the costs on maintenance, transportation, etc.
In addition, the contact element is made of an elastic metal material, thus avoiding the problem of non-metal materials, such as rubbers, which tend to be affected by temperature and damage the switch unit and other components, and further increasing the operation safety of the micro- switch of the present invention. Brief description of the accompanying drawings
The following accompanying drawings are only for
schematically describing and explaining the present invention and are not intended to limit the scope of the present invention, in which:
Fig. 1 is a partial exploded perspective view of a trigger mechanism for a manual alarm device including a micro-switch according to the present invention;
Fig. 2 is an illustrative sectional view of the micro- switch shown in Fig. 1 when it is in the on state;
Fig. 3 is an illustrative sectional view of the micro- switch shown in Fig. 1 when it is in the initial off state; and
Fig. 4 is an illustrative sectional view of the micro- switch shown in Fig. 1 when it is in the full off state.
Description of the reference numerals of components:
20 circuit board assembly 24 switch unit
40 operating element 46 contact element 462 fixed portion 464 contact portion
Exemplary embodiments
For the sake of better understanding of the technical features, objects and effects of the present invention, particular embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which the same reference numerals refer to the same parts.
FIG. 1 is a partial exploded perspective view of a trigger mechanism of a manual alarm device including a micro- switch according to the present invention. The housing of the manual alarm device and the guiding device or rails in the housing for mounting or moving the trigger mechanism are not shown in the figure. Preferably, the housing of the manual alarm device includes a base and an upper cover. The micro- switch includes a circuit board assembly 20, an operating element 40 and a contact element 46. The circuit board assembly 20 includes a switch unit 24, and a pair of lugs 44 are provided on the operating element 40 (with only one of the lugs 44 being schematically shown in Fig. 1), and the operating element 40 can pivot about the lugs 44 and move in the off direction as shown in Fig. 1 when it is pressed along the press direction shown in the figure, thus realizing the off state of the micro-switch.
The contact element 46 includes a fixed portion 462 and a contact portion 464. The fixed portion 462 is mounted on the operating element 40, and as the operating element 40 moves, the contact element 46 can move with it, thus bringing the contact portion 464 of the contact element 46 to separate from or come into contact with the switch unit 24 on the circuit board assembly 20, thereby realizing the on or off state of the micro-switch.
The contact portion of the contact element 46 is bent into a U shape. Those skilled in the art would understand that the U shape referred to here is not in a strictly geometric sense and it can also include other shapes similar to the U shape or shapes having similar functions in an engineering sense, such as a V shape, a concave shape, etc. There are gaps between the two arms of the U-shaped contact portion 464 of the contact element 46, and during the process of making contact with the switch unit 24, the contact portion 464 of the contact element can be deformed to reduce the distance between the two arms, thereby increasing the operating tolerance of the operating element 40 during its operating. That is to say, even when an operator presses the operating element 40 with too large a force, the U-shaped contact portion 464 can generate a certain buffering effect, thus avoiding any direct damage to the switch unit 24 and/or circuit board assembly 20 (which will be particularly
described in Fig. 3) .
Although two switch units 24 are shown in Fig. 1, those skilled in the art would understand that the number of switch units 24 on the circuit board assembly 20 can be one or more than one, and the number of contact elements 46 can be set according to the number of switch units 24 and particular requirements in use. Only one contact element 46 is
schematically shown in Fig. 1.
In another preferred embodiment of the micro-switch of the present invention, the fixed portion 462 of the contact element 46 is detachably fixed to the operating element 40, and particularly, this fixed connection can be realized by means of engagement between a buckle and a groove or any other manner of detachable connections known to those skilled in the art .
In yet another preferred embodiment of the micro-switch of the present invention, the contact portion 464 of the contact element is made of an elastic metal material, such as copper, etc, thus avoiding the problems of the components such as the switch unit being damaged by creeping deformation or aging of engineering plastics induced by high temperature, thereby further improving the operation safety of the micro- switch of the present invention. Now the operating process of the micro-switch from the on state to the off state will be described in conjunction with Figs . 2 to 4.
Fig. 2 is a schematic diagram of the micro-switch when it is in the on state. As shown in Fig. 2, when the micro- switch is in the on state, the two ends of the operating element 40 are under two forces Fl and F2, keeping it in a stable position. For example, force Fl can be achieved by a stop block, a hook (not shown in the figure) and so on, and force F2 can be achieved by a spring, a leaf spring and so on (not shown in the figure) , and those skilled in the art can make a design according to different application
circumstances of the micro-switch, which will not be
described redundantly here. At this moment, the contact portion 464 of the contact element 46 is in contact with the switch unit 24 of the circuit board assembly 20, keeping the micro-switch in the on state. When the micro-switch needs to be opened, the operating element 40 can be pushed in the press direction indicated by the arrow shown in Fig. 2.
As shown in Fig. 3, the operating element 40 will pivot about the lugs 44 when the operating element 40 is pressed, if at this moment the operator exerts too large a force on the operating element 40, it may cause the moving journey of the operating element 40 to go beyond the limit, at this moment, the U-shaped portion of the contact portion 464 of the contact element 46 is deformed and the distance between the two arms of the U shape is less than the original
distance shown by the dash lines, and this deformation of the U-shaped portion achieves an over-force compensation, which in turn protects the switch unit 24 and/or the circuit board assembly 20 from being damaged due to the over-length moving journey of the operating element 40, so that the switch unit 24 can still operate normally even if the contact portion 464 is in close contact therewith.
After the operating element 40 has turned over a certain angle, the force F2 acting on the operating element 40 disappears (for example, the operating element moves away from the stop block, etc.), then the operating element 40 can move along the off direction shown in Fig. 3 under the force Fl and finally arrive at the position shown in Fig. 4, then the contact portion 464 is separated from the switch unit 24, and the off state of the micro-switch can be realized after the operator's pressing of the operating element.
It can be seen herewith that the micro-switch of the present invention has a relatively large operating tolerance, which improves the operation safety during its operation, even in the case of the external force being excessive, the excessive external force can be compensated by the
deformation of the U-shaped contact portion of the contact element, so that the switch unit and/or the circuit board assembly can be prevented from being damaged by the external force, thereby reducing the maintenance costs. In addition, the contact element made of a metal material does not tend to be affected by temperature or aging, which enhances safety. The detachable connection between the contact element and the operating element also improves the replaceability of the
components when being worn out, thereby further reducing the maintenance costs. The detailed description set forth above is only
directed to the particular description of viable embodiments of the present invention and is not intended to limit the protective scope of the present invention, and equivalent embodiments and variations made without departing from the technical spirit of the present invention shall be included in the protective scope of the present invention.