EP1858043B1 - Position switch with movable contacts having positive operation - Google Patents
Position switch with movable contacts having positive operation Download PDFInfo
- Publication number
- EP1858043B1 EP1858043B1 EP20070009214 EP07009214A EP1858043B1 EP 1858043 B1 EP1858043 B1 EP 1858043B1 EP 20070009214 EP20070009214 EP 20070009214 EP 07009214 A EP07009214 A EP 07009214A EP 1858043 B1 EP1858043 B1 EP 1858043B1
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- EP
- European Patent Office
- Prior art keywords
- position switch
- contacts
- pair
- stationary contacts
- movable contacts
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
- H01H13/02—Details
- H01H13/12—Movable parts; Contacts mounted thereon
- H01H13/14—Operating parts, e.g. push-button
- H01H13/18—Operating parts, e.g. push-button adapted for actuation at a limit or other predetermined position in the path of a body, the relative movement of switch and body being primarily for a purpose other than the actuation of the switch, e.g. door switch, limit switch, floor-levelling switch of a lift
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
- H01H13/02—Details
- H01H13/26—Snap-action arrangements depending upon deformation of elastic members
- H01H13/28—Snap-action arrangements depending upon deformation of elastic members using compression or extension of coil springs
- H01H13/32—Snap-action arrangements depending upon deformation of elastic members using compression or extension of coil springs one end of spring being fixedly connected to the stationary or movable part of the switch and the other end reacting with a movable or stationary rigid member respectively through pins, cams, toothed, or other shaped surfaces
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H3/00—Mechanisms for operating contacts
- H01H3/001—Means for preventing or breaking contact-welding
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H3/00—Mechanisms for operating contacts
- H01H3/32—Driving mechanisms, i.e. for transmitting driving force to the contacts
- H01H3/40—Driving mechanisms, i.e. for transmitting driving force to the contacts using friction, toothed, or screw-and-nut gearing
Definitions
- the present invention is generally applicable to the field of basic electric devices, and particularly relates to a position switch with movable contacts having positive operation, as described in the preamble of claim 1.
- This switch is particularly useful for safe control of moving parts of machines and systems and for causing shut-down thereof upon detection of end positions.
- Position switches are known to be used for positioning, controlling and checking moving parts of automatic machines and systems, such as in end position detection, to cause safe automatic shut-down.
- switches have a mechanical actuator for switching from a primary shut-down circuit, which closes to cause the machine or system to start, to an auxiliary signaling circuit, which closes to cause the machine or system to stop. Switching occurs by displacing one or more movable contacts from a first position in which they are coupled with the stationary contacts of the primary circuit to a second position in which they are coupled with the stationary contacts of the auxiliary circuit.
- Prior art switches use double-break movable contacts, of either simple or double-bridge type, wherein the contacts consist of pads of silver or other metals having suitable electrical conductivity properties.
- the above switches further have high contact resistances. Particularly, in switches with single-bridge double-break movable contacts, total resistance is twice the resistance of each contact and total switching failure probability is a quadratic function of the failure probability for each break. In double-bridge, double-break movable contacts resistance is as high as in simple movable contacts and switching failure probability is lower, though not negligible.
- switches to include contacts having a positive operation, through the use of a lever or other positive opening device, whereby the movable contacts may be applied a higher opening force than the maximum expected adhesion force between movable and stationary contacts.
- the above type of switch is known, amongst other, from US 5,453,590 and is composed of a bridge-like movable contact susceptible of being alternately forced against the stationary contacts of shut-down and signaling circuits by means of a pushing rod which operates on a bistable spring.
- the object of the present invention is to overcome the above drawbacks, by providing a position switch with movable contacts having positive operation that is highly efficient and relatively cost-effective.
- a particular object is to provide a small-size and low cost position switch.
- Yet another object is to provide a highly reliable position switch, while reducing switching failure probabilities.
- a double-bridge, single-break type position switch is provided, which reduces the total contact resistance between the movable contacts and the stationary contacts.
- the total resistance between movable and stationary contacts, upon passage of high currents, is relatively low, so that positive operation means will have to oppose lower adhesion forces than in prior art switches, and may involve lower sizes and costs.
- Another important aspect is that at least one pair of stationary and movable contacts is used, to further reduce total mutual resistance.
- the position switch with movable contacts having positive operation automatically switches a supply current from a primary shut-down circuit to an auxiliary signaling circuit of a machine or system.
- the switch may be used for controlled shut-down of an automatic or semiautomatic machine or system, and particularly for detection of end positions.
- the position switch of the invention has a common input terminal 2 to be connected to a per se known voltage source, not shown in the figures one first and one second output terminals 3, 4, suitable to be connected to a primary shut-down circuit and to an auxiliary signaling circuit of a machine or system respectively, also not shown, one first pair of stationary contacts 5 and one second pair of stationary contacts 6 electrically connected respectively to the first and second output terminals 3, 4, one pair of movable contacts 7 electrically connected to the common input terminal 2 and susceptible of alternately interacting with corresponding stationary contacts 5, 6 of the first and second pairs.
- the movable contacts 7 are normally in contact with the first pair of stationary contacts 5 and means 8 are further provided for positive operation of the pair of movable contacts 7 to move them apart from the first pair of stationary contacts 5, thereby causing positive opening of the primary circuit and simultaneous closing of the auxiliary circuit.
- positive operation means 8 shall have no elastic connection with the movable contacts 7, whose separation from the stationary contacts 5 of the first pair shall directly result from a specific movement of an appropriate actuator by means of non elastic members.
- the movable contacts 7 will be forced to open even when contacts are stuck together due to occasional passage of a high voltage, such as during a short circuit.
- movable contacts 7 can provide a double-bridge, simple-break switch.
- Contacts 5, 6, 7 will essentially consist of pads of silver or another metal, or anyway a material having suitable electrical conductivity properties.
- the movable contacts 7 will be electrically connected to the common input terminal 2 by articulated electrical connection means 9.
- Such means 9 comprise a first elongated member 10, defining a longitudinal axis X, with a longitudinal end 11 mechanically and electrically coupled to the common input terminal 2 and the opposite longitudinal end 12 having such a shape as to define a first substantially transverse pivot axis Y 1 , for a switching arm 13.
- This latter will comprise in turn a pair of elongated extensions 14, 15, which are appropriately shaped and substantially parallel to the longitudinal axis X.
- Each of such extensions 14, 15 has one of the movable contacts 7 at its free end 16, 17 remote from the first pivot axis Y 1 .
- the first output terminal 3 is connected to the first pair of stationary contacts 5 through a second elongated member 18, which is appropriately shaped and substantially parallel to the longitudinal axis X, having one end 19 electrically and mechanically connected to the first output terminal 3 and the opposite end 20 bearing the first pair of stationary contacts 5.
- the second output terminal 4 is connected to the second pair of stationary contacts 6 through a third elongated member 21, which is substantially parallel to the longitudinal axis X, having one end 22 electrically and mechanically connected to the second output terminal 4 and the opposite end 23 bearing the second pair of stationary contacts 6.
- the switching arm 13 is interposed between the second 18 and third 21 elongated members and is susceptible of pivoting in a substantially vertical plane ⁇ passing through the longitudinal axis X.
- the movable contacts 7 will be also interposed between the pairs of stationary contacts 5, 6 to move, by the pivotal movement ⁇ 1 of the arm 13, from the normal operating condition, in which they are coupled with the first pair of stationary contacts 5, as shown in FIG. 4 , to a shut-down condition, as shown in FIG. 5 , in which they are coupled with the stationary contacts 6 of the second pair.
- the positive operation means 8 include a pushbutton element 24 which is movable in a substantially vertical direction W and is operatively connected to a lever member 25 interposed between the switch arm 13 and the second elongate member 18.
- the lever element 25 is pivotable about a second transverse pivot axis Y 2 , in the vertical plane ⁇ .
- the lever element 25 is a first type lever which rotates about a pivot 27, defining the axis Y 2 , introduced in the side wall of the exterior case 29.
- the pushbutton element 24 has two specially shaped projections 31', 31" at its bottom end 30, which are particularly shown in FIG. 3 , facing towards corresponding tooth-shaped portions of the end 33 adjacent the lever element 25, one of which is only visible in the annexed figures and designated by 32, the second being placed symmetrically to the former with respect to the longitudinal axis X.
- the projections 31', 31" and the tooth-shaped portions 32 mutually interact to cause a pivotal movement ⁇ 2 of the lever element 25 about the second pivot axis Y 2 in response to a downward displacement w of the pushbutton element 24.
- the lever element 25 has a catch 35 at its longitudinal end 34 opposite the tooth-shaped portions 32, which is designed to interact with the elongate extensions 14, 15 of the switching arm 13 to cause positive opening of the primary shut-down circuit and closing of the auxiliary signaling circuit.
- Positive operation means 8 further include a first elastic member 36 for elastically and controllably counteracting the vertical motion of the pushbutton element 24.
- the first elastic member 36 is preferably a helical spring whose modulus is calibrated to allow vertical sliding of the pushbutton 24 once a predetermined external force F is applied thereon.
- the pushbutton 24 substantially has a hollow cylindrical shape, having an open lower end 30 and a closed upper end 37 to at least partly receive the spring 36.
- the spring 36 has one end section 38 attached to the bottom wall of the case 29 and the opposite end section, not visible, facing towards the closed end 37 of the pushbutton element 24.
- the positive operation means 8 include a second elastic member 39 which is received in a central housing 40 in the switch arm 13 to elastically and controllably counteract the pivotal motion ⁇ 1 thereof.
- the second elastic member 39 which is also preferably a helical spring, is substantially parallel to the switch arm 13, when the latter is in its normal operating condition in which the main shut-down circuit is closed.
- the second elastic member 39 is also in such position as to define two snap positions for the switch arm 13, i.e. a first limit stop position of the pushbutton element 24, as shown in FIG. 4 , and a second position in which the pushbutton element 24 has completed its snap stroke C s , as shown in FIG. 5 .
- the vertical downward displacement w of the pushbutton element 24 will involve interaction between the projections 31', 31" and the tooth-shaped portions 32, which will cause the pivotal movement ⁇ 2 of the lever element 25 and the positive mechanical operation of the switch arm 13, and thence of the movable contacts 7.
- positive mechanical operation as used herein is intended as the action of a mechanical component, in this case the projections 31', 31" which inevitably drives another component, i.e. the tooth-shaped portions 32, either by direct contact or through rigid elements.
- FIG. 4 shows a first operating position of the inventive switch, which corresponds to the normal operating condition, in which the stationary contacts 5 are coupled to the movable contacts 7. In these conditions, the primary shut-down circuit of the machine with the switch connected thereto is closed, whereby the machine is operating.
- FIG. 5 shows a second operating position of the inventive switch, in which the stroke C s of the pushbutton element 24 has caused the arm 13 to snap into pivotal movement ⁇ 1 to move the movable contacts 7 to contact engage the stationary contacts 6.
- the auxiliary signaling circuit of the machine is closed, so that the machine is in shut-down conditions. If high currents pass between the contacts 5 and 7, such as during a short-circuit, the adhesion forces between the contacts 5, 7 may be so strong that such snapping action might not occur, thereby causing serious danger for the machine and its operators.
- FIG. 6 shows a third operating position of the switch of the invention, in which a stroke C 1 , longer than the stroke C s , of the pushbutton element 24 has caused interaction between the projections 31 and the tooth-shaped portions 32 to cause the lever 25 to pivot ⁇ 2
- the lever element 25 has completed its positive opening stroke C 2 and has forced the switch arm 13 to deviate thereby causing positive separation of the movable contacts 7 from the first stationary contacts 5 and contact thereof with the second stationary contacts 6.
- such movement would cause the primary shut-down circuit to open, thereby resulting in a machine shut-down, any danger for the machine and the working personnel being thus prevented.
- FIG. 7 shows a fourth and last operating position of the switch of the invention, in which the pushbutton element 24 reaches the limit stop position corresponding to the maximum allowed mechanical stroke C MAX , longer than C 1 , which is advantageously longer than the positive opening stroke C 2 to provide an adequate stroke length, given by the difference between the maximum stroke C MAX and the positive opening stroke C 2 , within which the switch 1 is adjusted.
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- Rotary Switch, Piano Key Switch, And Lever Switch (AREA)
- Push-Button Switches (AREA)
Description
- The present invention is generally applicable to the field of basic electric devices, and particularly relates to a position switch with movable contacts having positive operation, as described in the preamble of claim 1.
- This switch is particularly useful for safe control of moving parts of machines and systems and for causing shut-down thereof upon detection of end positions.
- Position switches are known to be used for positioning, controlling and checking moving parts of automatic machines and systems, such as in end position detection, to cause safe automatic shut-down.
- These switches have a mechanical actuator for switching from a primary shut-down circuit, which closes to cause the machine or system to start, to an auxiliary signaling circuit, which closes to cause the machine or system to stop. Switching occurs by displacing one or more movable contacts from a first position in which they are coupled with the stationary contacts of the primary circuit to a second position in which they are coupled with the stationary contacts of the auxiliary circuit.
- Prior art switches use double-break movable contacts, of either simple or double-bridge type, wherein the contacts consist of pads of silver or other metals having suitable electrical conductivity properties.
- In the former case there is a single pair of movable contacts which is translated to contact a pair of stationary contacts connected to the auxiliary circuit to cause closure thereof and consequent shut-down of the machine.
- In the latter case, two pairs of movable contacts are provided, which are simultaneously translated to simultaneously contact respective pairs of stationary contacts of the auxiliary signaling circuit.
- Nevertheless, the occasional presence of high resistance of contacts, especially caused by the presence of a thin layer of oxide, dust or other impurities of various kinds embedded in the switch during wiring, may cause switching failures.
- Reiteration of this process not only depends on the switch but on the work environment in which it is situated and on the type of load under control. Effects are inversely proportional to the control voltage, as low voltage values may not be able to penetrate the oxide layers or dust.
- This kind of malfunctioning is generally tolerable in manual controls, where it can be solved by repeating the operation, whereas failed detection of a limit stop position may cause considerable damages for the machine and/or for the operator working thereon.
- The above switches further have high contact resistances. Particularly, in switches with single-bridge double-break movable contacts, total resistance is twice the resistance of each contact and total switching failure probability is a quadratic function of the failure probability for each break. In double-bridge, double-break movable contacts resistance is as high as in simple movable contacts and switching failure probability is lower, though not negligible.
- Specific technical standards further require switches to include contacts having a positive operation, through the use of a lever or other positive opening device, whereby the movable contacts may be applied a higher opening force than the maximum expected adhesion force between movable and stationary contacts.
- This need is particularly felt when high currents pass through the contacts, such as during a short circuit, in which event adhesion forces between the movable and stationary contacts reach very high values.
- The above type of switch is known, amongst other, from
US 5,453,590 and is composed of a bridge-like movable contact susceptible of being alternately forced against the stationary contacts of shut-down and signaling circuits by means of a pushing rod which operates on a bistable spring. - Nevertheless, this solution has such high switching failure probability and resistance values that, in case of high current passage, relatively high adhesion forces are generated between contacts. The above drawback obliges to oversize the opening mechanism, which causes an overall increase of bulkiness and costs of the whole device.
- From
EP-A-0411331 is known a switch having all the features of the preamble of the main claim 1. - The object of the present invention is to overcome the above drawbacks, by providing a position switch with movable contacts having positive operation that is highly efficient and relatively cost-effective.
- A particular object is to provide a small-size and low cost position switch.
- Yet another object is to provide a highly reliable position switch, while reducing switching failure probabilities.
- These and other objects, as better explained hereafter, are fulfilled by a position switch with movable contacts having positive operation according to claim 1.
- Thanks to this particular configuration according to the invention a double-bridge, single-break type position switch is provided, which reduces the total contact resistance between the movable contacts and the stationary contacts. Thus, the total resistance between movable and stationary contacts, upon passage of high currents, is relatively low, so that positive operation means will have to oppose lower adhesion forces than in prior art switches, and may involve lower sizes and costs.
- Another important aspect is that at least one pair of stationary and movable contacts is used, to further reduce total mutual resistance.
- Also, this will lower the likelihood of switching failures thus the switch will have a higher reliability.
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- Therefore, assuming that, for each break between a movable contact and a corresponding stationary contact, a switching failure occurs once every 10000 operations, there will be one switching failure every 100,000,000 operations. Experimental data showed that, in a switch with double-bridge, double-break movable contacts, assuming an identical error rate, there will be a wrong operation every 25,000,000.
- Such data show that the position switch with movable contacts having positive operation of the invention is four times more reliable than prior art switches.
- Further features and advantages of the invention will be more apparent from the detailed description of a preferred, non-exclusive embodiment of a position switch according to the invention, which is described as a non-limiting example with the help of the annexed drawings, in which:
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FIG. 1 is a side view of a position switch according to the invention in which the external case is partly open to make the interior of the switch visible; -
FIG. 2 is a perspective view of a detail of the switch ofFIG. 1 in normal operating conditions; -
FIG. 3 is a front view of the detail ofFIG. 2 ; -
FIG. 4 is a side view of the detail ofFIG. 2 in a first operating position with the machine or system to which the switch is connected is in function; -
FIG. 5 is a side view of the detail ofFIG. 2 in a second operating position; -
FIG. 6 is a side view of the detail ofFIG. 2 in a third operating position; -
FIG. 7 is a side view of the detail ofFIG. 2 in a fourth operating position with the pushbutton element in its end position. - Referring to the above figures, the position switch with movable contacts having positive operation, overall designated by numeral 1, automatically switches a supply current from a primary shut-down circuit to an auxiliary signaling circuit of a machine or system.
- The switch may be used for controlled shut-down of an automatic or semiautomatic machine or system, and particularly for detection of end positions.
- As shown in
FIG. 1 , the position switch of the invention has acommon input terminal 2 to be connected to a per se known voltage source, not shown in the figures one first and onesecond output terminals stationary contacts 5 and one second pair ofstationary contacts 6 electrically connected respectively to the first andsecond output terminals movable contacts 7 electrically connected to thecommon input terminal 2 and susceptible of alternately interacting with correspondingstationary contacts - While reference is being made herein to the
stationary contacts movable contacts 7 as "pairs", they may be provided in greater numbers, such as three, four, five or more, without departure from the inventive scope as defined in the annexed claims. - The
movable contacts 7 are normally in contact with the first pair ofstationary contacts 5 andmeans 8 are further provided for positive operation of the pair ofmovable contacts 7 to move them apart from the first pair ofstationary contacts 5, thereby causing positive opening of the primary circuit and simultaneous closing of the auxiliary circuit. - The expression "positive opening" as used herein is in accordance with the technical standard EN 60947-5-1, which constitutes the reference document for regulating devices for use in control circuits and control elements in low voltage equipments.
- According to such standard, positive operation means 8 shall have no elastic connection with the
movable contacts 7, whose separation from thestationary contacts 5 of the first pair shall directly result from a specific movement of an appropriate actuator by means of non elastic members. - Thus, the
movable contacts 7 will be forced to open even when contacts are stuck together due to occasional passage of a high voltage, such as during a short circuit. - Yet, appropriate arrangement of
movable contacts 7 relative tostationary contacts Contacts - In this configuration, designating Rc the contact resistance generated between each
movable contact 7 and the corresponding stationary contacts of the first 5 andsecond pairs 6 and assuming a simplified arrangement with substantiallyidentical contacts - As particularly shown in
FIG. 2 andFIG. 3 , themovable contacts 7 will be electrically connected to thecommon input terminal 2 by articulated electrical connection means 9. - Such means 9 comprise a first
elongated member 10, defining a longitudinal axis X, with a longitudinal end 11 mechanically and electrically coupled to thecommon input terminal 2 and the oppositelongitudinal end 12 having such a shape as to define a first substantially transverse pivot axis Y1, for aswitching arm 13. - This latter will comprise in turn a pair of
elongated extensions such extensions movable contacts 7 at its free end 16, 17 remote from the first pivot axis Y1. - The
first output terminal 3 is connected to the first pair ofstationary contacts 5 through a secondelongated member 18, which is appropriately shaped and substantially parallel to the longitudinal axis X, having oneend 19 electrically and mechanically connected to thefirst output terminal 3 and theopposite end 20 bearing the first pair ofstationary contacts 5. - In substantially the same manner, the
second output terminal 4 is connected to the second pair ofstationary contacts 6 through a thirdelongated member 21, which is substantially parallel to the longitudinal axis X, having oneend 22 electrically and mechanically connected to thesecond output terminal 4 and theopposite end 23 bearing the second pair ofstationary contacts 6. - Advantageously, the switching
arm 13 is interposed between the second 18 and third 21 elongated members and is susceptible of pivoting in a substantially vertical plane π passing through the longitudinal axis X. - Thus, the
movable contacts 7 will be also interposed between the pairs ofstationary contacts arm 13, from the normal operating condition, in which they are coupled with the first pair ofstationary contacts 5, as shown inFIG. 4 , to a shut-down condition, as shown inFIG. 5 , in which they are coupled with thestationary contacts 6 of the second pair. - Suitably, the positive operation means 8 include a
pushbutton element 24 which is movable in a substantially vertical direction W and is operatively connected to alever member 25 interposed between theswitch arm 13 and the secondelongate member 18. Thelever element 25 is pivotable about a second transverse pivot axis Y2, in the vertical plane π. - In the preferred, non exclusive configuration of the figures, the
lever element 25 is a first type lever which rotates about apivot 27, defining the axis Y2, introduced in the side wall of theexterior case 29. - The
pushbutton element 24 has two specially shapedprojections 31', 31" at itsbottom end 30, which are particularly shown inFIG. 3 , facing towards corresponding tooth-shaped portions of theend 33 adjacent thelever element 25, one of which is only visible in the annexed figures and designated by 32, the second being placed symmetrically to the former with respect to the longitudinal axis X. - The
projections 31', 31" and the tooth-shapedportions 32 mutually interact to cause a pivotal movement φ2 of thelever element 25 about the second pivot axis Y2 in response to a downward displacement w of thepushbutton element 24. - Furthermore, the
lever element 25 has acatch 35 at itslongitudinal end 34 opposite the tooth-shapedportions 32, which is designed to interact with theelongate extensions arm 13 to cause positive opening of the primary shut-down circuit and closing of the auxiliary signaling circuit. - Positive operation means 8 further include a first
elastic member 36 for elastically and controllably counteracting the vertical motion of thepushbutton element 24. - The first
elastic member 36 is preferably a helical spring whose modulus is calibrated to allow vertical sliding of thepushbutton 24 once a predetermined external force F is applied thereon. - In the particular configuration of the annexed figures, the
pushbutton 24 substantially has a hollow cylindrical shape, having an openlower end 30 and a closedupper end 37 to at least partly receive thespring 36. Thus, thespring 36 has oneend section 38 attached to the bottom wall of thecase 29 and the opposite end section, not visible, facing towards theclosed end 37 of thepushbutton element 24. - Also, the positive operation means 8 include a second
elastic member 39 which is received in acentral housing 40 in theswitch arm 13 to elastically and controllably counteract the pivotal motion φ1 thereof. - The second
elastic member 39, which is also preferably a helical spring, is substantially parallel to theswitch arm 13, when the latter is in its normal operating condition in which the main shut-down circuit is closed. - The second
elastic member 39 is also in such position as to define two snap positions for theswitch arm 13, i.e. a first limit stop position of thepushbutton element 24, as shown inFIG. 4 , and a second position in which thepushbutton element 24 has completed its snap stroke Cs, as shown inFIG. 5 . - In operation, the vertical downward displacement w of the
pushbutton element 24 will involve interaction between theprojections 31', 31" and the tooth-shapedportions 32, which will cause the pivotal movement φ2 of thelever element 25 and the positive mechanical operation of theswitch arm 13, and thence of themovable contacts 7. - The term positive mechanical operation as used herein is intended as the action of a mechanical component, in this case the
projections 31', 31" which inevitably drives another component, i.e. the tooth-shapedportions 32, either by direct contact or through rigid elements. -
FIG. 4 shows a first operating position of the inventive switch, which corresponds to the normal operating condition, in which thestationary contacts 5 are coupled to themovable contacts 7. In these conditions, the primary shut-down circuit of the machine with the switch connected thereto is closed, whereby the machine is operating. -
FIG. 5 shows a second operating position of the inventive switch, in which the stroke Cs of thepushbutton element 24 has caused thearm 13 to snap into pivotal movement φ1 to move themovable contacts 7 to contact engage thestationary contacts 6. In this operating position, the auxiliary signaling circuit of the machine is closed, so that the machine is in shut-down conditions. If high currents pass between thecontacts contacts -
FIG. 6 shows a third operating position of the switch of the invention, in which a stroke C1, longer than the stroke Cs, of thepushbutton element 24 has caused interaction between theprojections 31 and the tooth-shapedportions 32 to cause thelever 25 to pivot φ2 In this operating position, thelever element 25 has completed its positive opening stroke C2 and has forced theswitch arm 13 to deviate thereby causing positive separation of themovable contacts 7 from the firststationary contacts 5 and contact thereof with the secondstationary contacts 6. In case of short-circuit, such movement would cause the primary shut-down circuit to open, thereby resulting in a machine shut-down, any danger for the machine and the working personnel being thus prevented. -
FIG. 7 shows a fourth and last operating position of the switch of the invention, in which thepushbutton element 24 reaches the limit stop position corresponding to the maximum allowed mechanical stroke CMAX, longer than C1, which is advantageously longer than the positive opening stroke C2 to provide an adequate stroke length, given by the difference between the maximum stroke CMAX and the positive opening stroke C2, within which the switch 1 is adjusted. - The above disclosure clearly shows that the invention fulfills the intended objects and particularly meets the requirement of providing a small-size and low-cost position switch.
- Thanks to this particular arrangement of the stationary and
movable contacts
Claims (11)
- A position switch with movable contacts having positive operation for automatically switching a supply current from a primary shut-down circuit to an auxiliary signaling circuit of a machine or system, wherein said position switch comprises:- a common input terminal (2) connected to a voltage source;- one first and one second output terminals (3, 4), connectable respectively to a primary shut-down circuit and to an auxiliary signaling circuit of a machine or system;- at least one first (5) and at least one second (6) stationary contacts electrically connected to said first (3) and said second (4) output terminals respectively;- at least one pair of movable contacts (7) electrically connected to said common input terminal (2) and susceptible of alternately interacting with said at least one first (5) and one second (6) stationary contacts respectively, said at least one pair of movable contacts (7) being normally in contact engagement with said at least one first stationary contact (5);- means (8) for positive operation of said at least one pair of movable contacts (7) to cause them to move apart from said at least one first stationary contact (5) thereby causing positive opening of the primary circuit and simultaneous closing of the auxiliary circuit,wherein said movable contacts (7) and said common input terminal (2) are electrically connected by articulated electrical connection means (9),
characterized in that said at least one first (5) and at least one second (6) stationary contacts are pairs of stationary contacts, said articulated electrical connection means (9) comprising a first elongated member (10), defining a longitudinal axis (X), said member having a longitudinal end (11) mechanically and electrically coupled to said common input terminal (2) and the opposite longitudinal end (12) so shaped as to define a first substantially transverse pivot axis (Y1) for a switching arm (13). - Position switch as claimed in claim 1, characterized in that said switching arm (13) comprises a pair of elongated extensions (14, 15), which are substantially parallel to said longitudinal axis (X) and have said pair of movable contacts (7) proximate to their free ends (16, 17) remote from said first pivot axis (Y1).
- Position switch as claimed in claim 2, characterized in that said first output terminal (3) is connected to said first pair of stationary contacts (5) through a second elongated member (18), which is substantially parallel to said longitudinal axis (X), and has one end (19) electrically and mechanically connected to said first output terminal (3) with the opposite end (20) bearing said first pair of stationary contacts (5).
- Position switch as claimed in claim 3, characterized in that said second output terminal (4) is connected to said second pair of stationary contacts (6) through a third elongated member (21), which is substantially parallel to said longitudinal axis (X), and has one end (22) electrically and mechanically connected to said second output terminal (4) with the opposite end (23) bearing said second pair of stationary contacts (6).
- Position switch as claimed in any preceding claim, characterized in that said switching arm (13) is interposed between said second (18) and said third (19) elongated members and is susceptible of pivoting in a substantially vertical plane (π) passing through said longitudinal axis (X).
- Position switch as claimed in claim 1, characterized in that said positive operation means (8) include a pushbutton element (24) which is movable in a substantially vertical direction (W) and is operatively coupled to a lever element (25) pivotable about a second transverse pivot axis (Y2) in said vertical plane (π).
- Position switch as claimed in claim 6, characterized in that said lever element (25) is interposed between said switch arm (13) and said second elongated element (18).
- Position switch as claimed in claim 7, characterized in that said pushbutton element (24) has at least one, preferably two specially shaped projections (31', 31") at its lower end (30), which face towards corresponding tooth-shaped portions (32) on the adjacent end (33) of said lever element (25) to cause said lever element (25) to pivot (φ2) about said second pivot axis (Y2) in response to a downward displacement (w) of said pushbutton element (24).
- Position switch as claimed in claim 8, characterized in that said lever element (25) has a catch (35) at its longitudinal end (34) opposite said tooth-shaped portions (32), which is designed to interact with said elongate extensions (14, 15) of said switching arm (13) to cause positive opening of the primary shut-down circuit and closing of the auxiliary signaling circuit.
- Position switch as claimed in any preceding claim, characterized in that said positive operation means (8) further include a first elastic element (36) for elastically and controllably counteracting the vertical displacement (w) of said pushbutton element (24).
- Position switch as claimed in claim 10, characterized in that said positive operation means (8) further include a second elastic element (39) which is located in a central housing (40) in said switching arm (13) for elastically and controllably counteracting the pivotal motion (φ1) thereof.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITVI20060145 ITVI20060145A1 (en) | 2006-05-15 | 2006-05-15 | POSITION SWITCH WITH MOBILE CONTACTS WITH FORCED DRIVE |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1858043A1 EP1858043A1 (en) | 2007-11-21 |
EP1858043B1 true EP1858043B1 (en) | 2008-12-24 |
Family
ID=38134576
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20070009214 Active EP1858043B1 (en) | 2006-05-15 | 2007-05-08 | Position switch with movable contacts having positive operation |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP1858043B1 (en) |
CN (1) | CN101101826B (en) |
DE (1) | DE602007000395D1 (en) |
IT (1) | ITVI20060145A1 (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104269303B (en) * | 2014-09-26 | 2016-06-15 | 成都锐奕信息技术有限公司 | It is capable of the switch of accurately control |
CN104217869A (en) * | 2014-09-26 | 2014-12-17 | 成都锐奕信息技术有限公司 | Device capable of controlling moving stroke of part |
CN104269301B (en) * | 2014-09-26 | 2016-06-15 | 成都锐奕信息技术有限公司 | In the microswitch that mainframe computer is controlled |
CN104269304A (en) * | 2014-09-26 | 2015-01-07 | 成都锐奕信息技术有限公司 | Stroke control structure capable of improving responding efficiency |
EP3166123B1 (en) | 2015-11-09 | 2018-05-02 | Microprécision Electronics Holding SA | Electrical switch |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB765474A (en) * | 1954-02-11 | 1957-01-09 | Dowty Equipment Ltd | Improvements relating to snap-action electric switches |
GB1033014A (en) * | 1962-05-28 | 1966-06-15 | Otehall Ltd | Improvements in or relating to snap-action electric switches |
GB1113395A (en) * | 1965-10-26 | 1968-05-15 | Burgess Products Co Ltd | Improvements relating to electrical switch arrangements |
JPH0337922A (en) * | 1989-07-03 | 1991-02-19 | Omron Corp | Switch contact mechanism |
EP0773567B1 (en) * | 1995-11-10 | 1999-05-06 | Haschkamp, Joachim, Dipl.-Ing. | Push button switch |
JP3854789B2 (en) * | 2000-08-11 | 2006-12-06 | アルプス電気株式会社 | Switch device |
JP4256708B2 (en) * | 2003-04-03 | 2009-04-22 | アルプス電気株式会社 | Switch device |
-
2006
- 2006-05-15 IT ITVI20060145 patent/ITVI20060145A1/en unknown
-
2007
- 2007-05-08 EP EP20070009214 patent/EP1858043B1/en active Active
- 2007-05-08 DE DE200760000395 patent/DE602007000395D1/en active Active
- 2007-05-15 CN CN2007101464855A patent/CN101101826B/en active Active
Also Published As
Publication number | Publication date |
---|---|
EP1858043A1 (en) | 2007-11-21 |
CN101101826B (en) | 2012-07-25 |
CN101101826A (en) | 2008-01-09 |
ITVI20060145A1 (en) | 2007-11-16 |
DE602007000395D1 (en) | 2009-02-05 |
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