Patent Application
20080029376
Other advantages and features will become more clearly apparent from the following description of particular embodiments of the invention, given for non-restrictive example purposes only, and represented in the accompanying drawings in which:
In a first preferred embodiment of the invention as represented in
According to this embodiment, the electric control switch 1 comprises an electric contact 3 having at least a first and a second electric state. The electric contact 3 is preferably integrated in an electric cell 10 such as a microswitch. The electric cell 10 can comprise an operating push-button 11, movement whereof between two extreme positions brings about a change of electric state of the electric contact 3.
According to this embodiment as represented in
The electric contact 3 is held in the first electric state called rest state by a holding force fm generated by a flexible operating means 9.
The operating push-button 4 can move under the action of an external operating force FC between the rest position and the detection position. The rest and detection positions are represented respectively in
Said operating push-button 4 comprises a first operating means 5 on which the external operating force FC is designed to be applied. The first operating means 5 preferably comprise an external piston moving in translation along its longitudinal axis 100 inside the case 2. The movement travel of the external piston is limited by two positioning stops 21, 22. Preferably, the positioning stops 21, 22 form an integral part of the case 2.
According to a particular embodiment, the external piston comprises a cylindrical body having two ends. A first end comprises a first bearing face 50 on which the external operating force FC is applied. A second end of the external piston comprises a shoulder 51. An external face 52 of the shoulder 51 of the external piston comes into contact with the first stop 21 when the electric control switch 1 is in a rest position. A second stop 22 prevents movement of the external piston by means of the internal face 53 of the shoulder 51 when the electric control switch 1 is in its detection position.
In the rest position, the external piston is held against the first stop 21 by the action of at least one flexible return means 7. Said flexible means apply a return force FR on the external piston. The return force FR is designed to oppose the external operating force FC. The return force FR is preferably applied on the second end of the cylindrical body of the external piston. According to this example of embodiment, said at least one flexible return means 7 comprise a helical spring positioned between the bottom of the case and the internal face 53 of the shoulder 51 of the external piston.
The electric control switch 1 comprises disconnection means 6, 8, 9 between the first operating means 5 and the electric contact 3. The disconnection means 6, 8, 9 comprise means for moving the electric contact 3 from the first electric state to the second electric state and vice-versa at a speed having a predetermined maximum value. The speed of movement of the electric contact 3 is independent from the speed of the first operating means 5 when the speed of the first operating means 5 is higher than said predetermined maximum value. In other words, the disconnection means 6, 8, 9 enable a change of electric state of each electric contact 3 at a speed independent from the speed of the first operating means 5 of the operating push-button 4.
The operating push-button 4 comprises a second operating means 6 movement whereof causes the change of electric state of the electric contact 3. The second operating means 6 comprise an internal piston. Said piston internal comprises a longitudinal axis 100 coaxial with that of the external piston of the first operating means 5. Said second operating means 6 move in translation in a direction parallel to that of movement of the push-button 4.
According to one embodiment, the internal piston comprises a cylindrical body having two ends. The external surface of the cylindrical body has at least one flange 60. Said flange is preferably placed at a first end of said body. The internal piston comprises a bearing surface 61 designed to actuate the electric contact in the detection position. This bearing surface is preferably located at a second end of the piston. The internal piston is preferably hollow to be fitted sliding around the cylindrical body of the external piston.
According to a particular embodiment, the internal piston actuates the operating push-button 11 of the microswitch of the electric cell 10.
The disconnection means 6, 8, 9 comprise at least one flexible operating means 8 generating an internal operating force fc. This internal operating force fc fixes a first predetermined maximum value V1max of the speed of movement of the electric contact 3 from the first electric state to the second electric state.
This internal operating force fc is applied to the second operating means 6 to cause movement of the latter. The internal operating force fc is independent from the external operating force FC. The internal operating force fc is directly proportional to the stiffness of the flexible operating means 8.
The operating speed of the second operating means 6, in other words the speed of movement of the internal piston, will depend essentially on the internal operating force fc.
Moreover, the speed of movement of the second operating means 6 is independent from the speed of movement of the first operating means 5 when the speed of the first operating means 5 is greater than the first predetermined maximum value V1max.
According to this embodiment, said at least one flexible operating means 8 comprise a helical spring positioned between an internal surface of the case and the first end of the cylindrical body of the internal piston. The springs of the flexible operating means 8 and of the return means 7 are coaxial.
In the rest position of the electric control switch 1, the internal piston is held by the action of the internal operating force fc against a movable retractable first stop 23.
According to one embodiment of the invention, the movable retractable stop 23 forms an integral part of the external piston. The flange 30 of the internal piston is designed to come up against the stop formed by the external face 52 of the shoulder 51 of the external piston. The return force FR applied on the external piston is opposed to the internal operating force fc. Said return force then opposes movement of the piston internal indirectly. The return force FR is of greater intensity than the internal operating force fc.
Movement of the internal piston can only begin after the movable retractable stop 23 has been cleared. In other words, the internal piston cannot move when the external piston is positioned against the first stop 21, i.e. so long as the operating push-button 4 has not started its movement. Movement of the first operating means 5 due to the action of the external operating force FC releases movement of the second operating means 6 due to the action of the internal operating force fc.
The disconnection means 6, 8, 9 comprise an internal flexible operating means 9 generating a holding force fin on the electric contact or contacts 3. This holding force fin fixes a second predetermined maximum speed V2max of movement of the electric contact or contacts 3 from the second electric state to the first electric state.
Furthermore, the speed of movement of the electric contact 3 from the second electric state to the first electric state is independent from the speed of movement of the second operating means 6 when the speed of the second operating means 6 is greater than the second predetermined maximum value V2max.
The holding force fin opposes the internal operating force fc and is of lower intensity.
Operation of the electric control switch 1 is as follows.
Under the effect of the external operating force FC applied to the operating push-button 4, the first operating means 5 tend to move along their longitudinal axis 100. The electric control switch 1 leaves its rest state.
Movement of the first operating means 5 due to the effect of the external operating force FC releases movement of the second operating means 6. As soon as the movable retractable stop 23 is cleared, in other words as soon as the external piston starts to move, the internal piston in fact moves due to the action of the internal operating force fc.
Two operating modes are observable according to the speed of movement of the first operating means 5.
If the speed of movement of the first operating means 5 is greater than the first predetermined maximum speed V1max imposed by the internal operating force fc, the external and internal pistons move in the same direction but at different speeds. The external piston driven by the external operating force FC moves more quickly than the internal piston. Said internal piston then loses contact with the retractable stop 23. The speed of movement of the internal piston is then solely dependent on the operating force fc. Said operating force is calibrated in such a way that the operating speed and the force of impact of the internal piston on the electric contact 3 of the electric cell are not responsible for damage to said electric contact 3. According to this embodiment, the first operating means 5 can reach the second stop 22 before the internal piston has brought about the change of electric state of the electric contact 3. The first operating means 5 can then position itself on the second stop 22 before the electric control switch 1 is in its detection state.
If the speed of movement of the first operating means 5 is lower than or equal to the first predetermined maximum speed V1max imposed by the internal operating force fc, the external and internal pistons move in the same direction and at the same speed. The internal piston remains in contact with the movable retractable stop 23 during its movement. The speed of movement of the internal piston, substantially equal to that of the first operating means 5, is then imposed by the external operating force FC. According to this embodiment, in a first phase of the movement, the two internal and external pistons move together up to the moment when:
The internal or external piston still in movement then finishes its travel and is immobilized in turn. The electric control switch 1 is then in its detection state.
In general manner, when the speed of movement of the first operating means 5 of the push-button 4 is greater than the first predetermined maximum speed V1max, the operating speed of the second operating means 6 only depends on the internal operating force fc; in other words the speed of movement of the electric contact or contacts 3 from the first electric state to the second electric state is totally independent from the speed of movement of the first operating means 5. In addition, the force of impact of the internal piston on the electric contact or contacts 3 is then also totally independent from the external operating force FC. In all cases, the maximum speed of the internal piston is imposed by the internal operating force fc.
Disconnection between the first operating means 5 and the electric contact or contacts essentially concerns the speed of movement of the external piston and the speed of change of electric state of the electric contact 3. Moreover, disconnection also concerns the intensity of the external operating force FC applied to the operating push-button 4 and the internal operating force fc tending to change the electric state of the electric contact 3.
When the external operating force FC is annulled, the electric control switch will leave its detection state and return to a rest state. The first operating means 5 then tend to move in the opposite direction due to the action of the return force FR.
According to this embodiment, as represented in
During its movement, the external piston will drive the internal piston in translation, which piston has again come into contact with the movable retractable stop 23 of the external piston. As the return force FR is greater than the internal operating force fc, movement of the first operating means 5 causes that of the second operating means 6.
According to this embodiment, the internal piston then releases the pressure exerted on the electric contact 3 of the electric cell 10. Said electric contact resumes a rest position due to the action of the holding force fm of the internal flexible operating means 9. Said holding force fm fixes the second predetermined maximum speed V2max of movement of the electric contact 3 from the second electric state to the first electric state. The speed of movement of the electric contact 3 from the second electric state to the first electric state is independent from the speed of movement of the second operating means 6 when the speed of the internal piston of the second operating means 6 is greater than the second predetermined maximum value V2max.
As the return force FR is generally much greater than the holding force fm, the speed of change of electric state of the electric contact 3 is then fixed by the internal flexible operating means 9.
Thus, when the control switch returns to the rest position, disconnection is then observed between the speed of movement of the operating push-button 4 and the speed of change of electric state of the electric contact or contacts.
According to a first alternative embodiment, the electric cell which comprised three contacts A, B, C can be replaced by an electric cell with two contacts A, B. In this case, the first electric terminal A is disconnected from the second electric terminal B when the switch is in a rest state. In addition, the first electric terminal A is connected to the second electric terminal B when the electric control switch is in a detection state.
According to a second alternative embodiment, the electric control switch with a push-button comprises several electric cells. The electric control switch with a push-button can in fact be two-pole, three-pole or four-pole.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06 07036 | Aug 2006 | FR | national |
