JPH0154811B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a snap actuated switch. For example, British Patent Specification No. 1529056 (or
A known snap-actuated switch, described in Publication No. 51-73268, has a resilient blade consisting of two cantilevered arms, which can be operated at their free ends by contact elements welded to the two arms. The arms are then interconnected with the arms drawn together and the blades stressed to permit a snapping movement of the contact elements relative to the fixed contacts of the switch.

To create such a snap-actuated switch, a contact element must be welded to the cantilever arm while maintaining the arm in a stressed position.
Welding the contact element to the cantilever arm of such a switch blade requires consistent quality welding from main to tail, and therefore requires precision fabrication. Furthermore,
Since the contacts can only be welded to one side of the switch blade, this technique can only be applied to single-throw switches.

SUMMARY OF THE INVENTION An object of the present invention is to provide a snap-actuated switch in which permanent welding of the contact element to the switch blade is avoided without adversely affecting the electrical characteristics of the switch. Another object of the invention is to provide a switch as described above which can be used as a transfer switch.

The present invention is a snap-actuated switch having a resilient blade, the blade comprising a pair of cantilevered arms connected to each other at their respective free ends by a contact-carrying connecting element, the connecting element being a pair of cantilevered arms connected to each other at their respective free ends by a contact-carrying connecting element. a snap-actuating switch for applying an internal force to the blade for snapping movement by engaging the laterally outer edges of the free ends and drawing the arms together; rims projecting in a direction towards each other, the ends of the rims extending parallel to each other and perpendicular to said direction, said connecting element having a pair of opposing surfaces, said connecting element having a pair of opposing surfaces; A surface engages the laterally outer edge of the end of the rim to impart the internal force to the blade and to resist angular movement and deflection of the rim when the coupling element is snapped by the blade. To provide a snap actuated switch characterized in that it allows.

Since the snap actuation switch of the present invention does not include welding in the manufacturing process of the elastic blade, dimensional quality control is easy.

Embodiments of the present invention will be described with reference to the drawings.

Referring first to FIGS. 1-3, the important components of a snap-actuated switch in accordance with the present invention are illustrated. The switch has a resilient Q-shaped blade 1, which has a base 2 and two cantilevered arms 3, 4 projecting therefrom in directions substantially parallel to each other. Both cantilevered arms have at their free ends respective rims 5, 6 projecting in the direction towards each other, the rims 5, 6 being substantially at right angles thereto, and respective ends 7 projecting outwardly from it substantially parallelly; Ends in 8.

The blade 1 is formed with an integral inner tongue 9 which is arranged symmetrically between the arms 3, 4 and projects towards the rims 5, 6. The tongue piece 9 has an arcuate upright piece 10 formed near its free end, with which a switch actuator 11 (FIG. 2) engages.

The blade 1 further has an outer tongue 12 which projects outwardly from the base 2 in the opposite direction to the inner tongue 9 and is provided at its end with a flat mounting tongue 13 in which two fixing holes 14 are formed. .

The switch blade 1 is configured to be attached to a fixed support (not shown), usually a conductive terminal piece, by means of a rivet (not shown) passing through a fixed hole 14, and the blade 1 is attached to the fixed support (not shown), which is usually a conductive terminal piece. Projects in a cantilevered manner. One of the fixing holes 14 is laterally elongated and allows slight adjustment of the position of the blade when attaching it to its fixed support.

The switch blade 1 is formed from a raw material plate of an elastic conductive metal such as beryllium copper in a single press operation. A stamped sheet metal blade 1 is shown in plan view in FIG. The upright piece 10 of the inner tongue piece 9 is formed at the same time in a pressing operation in which the blade 1 is cut from a metal plate. Fourth
Referring to the figure, even though the two ends 7, 8 are approximately perpendicular to the respective rims 5, 6, they are actually inclined at approximately 3 degrees from the strictly perpendicular direction, with the ends 7, 8 pointing towards their free ends. As time goes by, they move away from each other. This makes it possible to stress the blade for the next snapping operation, which is usually done before securing the blade to the fixed support, but can also take place after the blade is secured.

In order to prestress the blades, the outer corners 15, 16 of the blades after the connection of the arms 3, 4 with the respective rims 5, 6 press the two rims 5, 6 towards each other, e.g. with the respective tools. (not shown) receives an inwardly directed force. As shown in FIG. 4, the outer corners 15, 16 of the blade may be suitably rounded to facilitate engagement thereof by a blade deforming tool. When the rims 5, 6 are deformed inwardly toward each other, the blade 1 is deformed as a whole into a saucer shape, for example in the state shown in exaggerated form in FIG. However, they remain separated by a small gap.

As described above, stress is applied to the initially flat blade 1 by deformation, and the contact element 17 is moved to the protruding ends 7, 8.
sticks to. The contact element 17 has an elongated bar formed in the center with a slot 18 extending over its entire width, the length of which extends between the two blade ends 7, 8, as shown in FIG. This is to provide a gap. Simply lay the contact element 17 over the ends 7, 8 and then at the opposite corner 1 of the blade.
When the pressure applied 5, 16 is released, the ends 7, 8 are forced outwardly by the pre-applied stress on the blade and engage the ends of the slot 18.
The elastic engagement of the edges of the ends 7, 8 with the ends of the slot 18 suffices to hold the contact element 17 on the blade by friction alone. However, to further assist in retaining the contact element 17, the ends 7, 8 are made long enough to protrude beyond the contact element 17 and through the slot 18, and the protruding ends of the ends 7, 8 are deformed to form the contact. Element 17 may be prevented from coming off thereafter.
Alternatively, the ends 7, 8 can be cut off at the bottom to form heels 19, 20, respectively, which extend away from each other, as shown broken in FIG. , extending beyond the ends of the slot 18 to securely hold the contact element 17 at the ends.

The slot 18 in the contact element 17 tapers in width from its center toward both ends.
is a flat plate which flows from the center of the slot towards the ends of the slot and which is engaged by the flat ends 7, 8 of the blade in different operating conditions of the blade, as explained in connection with FIGS. 2 and 3. It is defined by a surface.

The contact element 17 has on opposite longitudinal edges individual contact surfaces 21, 22 of convex cross-section which engage respective fixed contacts in different operating positions of the blade.
is formed. In the figure, only one fixed contact 23 is shown for simplicity. The fixed contact 23 is located at one position of the blade (FIG. 1) and has a convex contact surface 21.
and a convex contact surface that makes electrical contact at an intermediate point.

The elongated contact elements 17 are extruded from metal extrusions to the required cross-sectional shape, then drilled at spaced intervals to form through slots 18, and then cut to form the individual contact elements 17. . Alternatively, drilling and cutting the extruded profile can be performed in a single operation.

In the closed state of the switch arrangement shown, the contact element 17 is pressed against the stationary contact 23 by contact pressure resulting from the elasticity of the prestressed blade 1, which in this form has an upwardly convex dish shape. The two arms 3, 4 are then pressed downwardly towards the fixing point 23 and below the level of the inner tongue 9. The two limbs 5, 6, seen from the free end of the blade (FIG. 3), slope upwardly toward each other;
The ends 7, 8 are in contact with the upper flat surface of the slot 18 of the contact element 17. The contact pressure that presses the contact element 17 against the fixed contact 23 is such that at this position, the switch blade is pressed to a stable position where the contact element 17 is held in a position beyond the fixed contact 23 due to the pre-applied stress. arise from things. Thus, in the illustrated form, the switch is a normally closed switch in which the contact element 17 is held in contact with the stationary contact 23 by the pre-stress of the blade 1.

When the cap is hung downwardly on the inner tongue 9 of the switch blade, as shown in FIGS.
The tongue 9 flexes to snap the blade from the upwardly convex configuration shown in FIG. 1 to the upwardly concave configuration shown in FIG. Along with this snap deformation, the arms 3 and 4 also snap upward relative to the fixed contact 23, and the contact element 17
3, the switch quickly rises to the open position (Figure 2).

If the switch blade is configured for monostable operation, it normally occupies the position shown in FIG. can. The pressure may be drawn from, for example, a bellows or other temperature or pressure sensitive means.

In the position shown in FIG. 2, where the contact surface 21 is separated from the fixed point 23, the other contact surface 22 of the contact element 17
may contact other fixed contacts (not shown) to enable the switch to be used as a transfer switch.

When the switch blade is in the upwardly concave configuration shown in FIG. , 8 contact the lower flat surface defining the slot 18 as shown in phantom in FIG. When the blade makes a snapping change from the configuration shown in FIG. 1 to the configuration shown in FIG. Get noticed. In making this change, the ends 7, 8 pass through a highly unstable position where they are in a common plane and spaced from the opposing boundary surfaces of the slot 18. Therefore, the ends 7, 8 quickly move from this unstable position and the slot 1
8 and then the contact element 17 separates from the fixed contact 23. As a result, the contact pressure between contact element 17 and contact 23 increases instantaneously just before the contact opens. Such pre-snap contact pressure is beneficial to switch actuation and increases the rate at which the contacts ultimately separate.

The contact element 17 is made of metal, preferably silver;
It acts as an effective heat sink to dissipate the heat generated when the contacts open. The contact element 17 can be made of solid silver, but a composite construction can also be used, for example a contact element made of brass with a silver or other conductive coating.
If the contact element 17 is intended to open and close only a single contact, it can be a laminated structure with a silver contact strip affixed to brass or other thermally conductive support material.

The construction of the switch according to the invention eliminates the need to weld contacts to the free ends of the cantilever arms 3, 4 of the switch blade 1. Furthermore, the "pivotal" connection between the ends 7,8 of the blade arms and the contact element 17 actually allows a floating connection between the contact element 17 and the switch blade, stressing the protruding ends 7,8. This provides a reliable electrical contact between the switch blade and the contact element 17.

In order to avoid friction between the contact element 17 and the switch blade, there must always be a gap between the contact element 17 and the outer edge of the rim of the switch blade. As previously mentioned, secure retention of the contact element 17 on the projecting ends 7, 8 is obtained by cutting off the lateral outer edges of the ends 7, 8, around which the end 7 is secured. , 8 "pivot" within the slot 18.

A second embodiment of the invention is shown in FIGS. 5 and 6, which also eliminates the need for welding the contacts to the switch blade. In this variant, the ends 7,
8 are pulled together to prestress the switch blade. The connecting piece 25 does not necessarily have to be a good conductor, but may be a steel strip or a crevice, for example. A further contact element 27 is fixed to the free end of the blade by an integral rivet 28,
The contact element 27 makes good electrical contact with the flat ends 7, 8 of the blade, and the shank of the rivet 28 connects the connecting piece 2.
It passes through 5.

Contact element 27 may be a bimetallic construction including a body of copper or other suitable electrical conductor and a contact head of silver or silver alloy. Alternatively, the entire contact element 27 may be made of silver or a silver alloy, providing two contact surfaces intended for use as a transfer switch, with a shaft of the same material making good electrical contact with the switch blade itself.

In a third embodiment of the invention, the switch blade 1 does not itself carry switch contacts, but operates a contact carrying arm. With reference to FIGS. 7 to 9,
A cantilever arm 30 of conductive material, for example beryllium copper, is fixed to the fixed support with the same rivets that attach the blade 1 to the fixed support. cantilever arm 30
has near its free end an upright tongue 31 deformed from the arm 30, which tongue 31 acts as a connecting piece and has a transverse slot 18 into which the ends 7, 8 of the blade 1 fit. . Arm 30 has at its free end a switch contact 27 attached to the arm by welding or riveting.

As described above, the inward deformation of the rims 5, 6 toward each other imparts a dish-shaped deformation to the blade 1. The two ends 7, 8 are close to each other and lie approximately parallel to each other but separated by a small gap. the stressed end 7 of the blade 1;
8 is a tongue piece 3 attached to an arm 30 of a cantilever conductor.
1 into the slit 18. After the ends 7, 8 have been introduced into the slot 18, the pressure exerted on the outer corners 15, 16 of the blade 1 is then released, with the ends 7, 8 being exposed to the elasticity of the stressed blade. The ends 7, 8 are pressed outward by
The side outer edges of the slot 18 are engaged with both ends of the slot 18.
By elastically engaging both ends of the end portions 7 and 8 with both ends of the slot 18, the end portions 7 and 8 can be held in a state in which they are engaged with the tongue piece 31.

The flat mounting tab of the blade is fixed to the fixed support together with the adjacent end of the conductor arm 15 by a rivet passing through the hole 14.

The slot 18 of the tongue 31 may be tapered from its center toward both ends, similar to the slot in the embodiments of FIGS. 1-3.

Contact 27 cooperates with fixed contact 23. The switches shown in Figures 7 to 9 have contacts 27 and 23.
As shown in FIGS. 7 and 8, this is a normal switch which is separated in the normal state of the switch. In this state, the prestressed blade 1 has an upwardly convex dish shape, and the two arms 3 and 4 have inner tongues 9.
is pressed downward to the bottom. The two rims 5, 6, viewed from the free end of the blade, are inclined upwards towards each other, so that the ends 7, 8 are in contact with the upper surface of the slot 18 of the tongue 31.

When the switch actuating member 11 engaged with the upright piece 10 applies downward force to the inner tongue of the switch blade as shown in FIG. The snap changes from an upwardly convex shape in the figure to an upwardly concave shape as shown in FIG. This snap change is accompanied by an upward snapping movement of the two arms 3, 4, so that the arm 30 carried by it and the contact 27 rise and engage the fixed contact 23, causing the switch to be in the closed position (9th position).
Figure).

The pressure pushing the contact 27 into the closed position relative to the fixed contact 23 is derived from the stress previously applied to the blade 1 to push the contact 27 into a stable position beyond the fixed point 23.

If the switch blade is configured for monostable operation, it will normally occupy the position shown in FIG. 8, but will remain in the position shown in FIG. 9 as long as actuating force is applied by the actuating member 11. This force may be induced, for example, by a bellows or other temperature or pressure sensitive actuation device.

If the switch is used as a transfer switch, another contact 27A can be provided on the opposite side of the cantilever arm 30 from the contact 27 (FIGS. 8 and 9).
When the contacts 27 and 23 are separated, the contact 27A comes into engagement with the other fixed contact 23A. Contact 27
A, 23A are shown in broken lines in FIGS. 8 and 9.

When the switch blade forms an upwardly concave dish shape (FIG. 9), the two limbs 5, 6 of the blade, viewed from the free end of the blade, slope downwardly towards the fixed contact 23A, so that the end 7 and 8 are slot 18
is joined to the lower surface defining the During the snapping movement, the ends 7, 8 pass through a very stable position in which they are coplanar.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the components of a snap actuation switch according to a first embodiment of the present invention in a closed state;
Figure 2 is a perspective view of the switch components shown in Figure 1 in an open state, Figure 3 is an end view in the direction of the arrow in Figure 1, and Figure 4 shows the components shown in Figures 1 through 3. FIG. 5 is a partial plan view of a switch blade according to a second embodiment of the present invention, and FIG. 6 is an end face in the direction of the arrow in FIG. 5. 7 is a perspective view of the components of a snap actuating switch according to a third embodiment of the present invention, FIG. 8 is a side view of the switch shown in FIG. 7 in an open state, and FIG. FIG. 3 is a side view showing the switch in a closed state. 1: Elastic blade, 3, 4: Cantilever arm, 5,
6: Rim, 7, 8: Blade end, 17: Contact element, 18: Hole (slot), 21, 22: Contact surface,
23: Fixed contact.

Claims (1)

Claims: 1. A snap-actuated switch having a resilient blade 1, the blade having a contact-carrying coupling element 1;
It consists of a pair of cantilever arms 3, 4 whose free ends are connected to each other by means 7; 25; In the snap actuating switch which applies an internal force to the blade for snapping movement by drawing both arms together, the blade 1 has rims projecting from the free ends of the arms 3 and 4 in a direction toward each other. 5, 6, the ends 7, 8 of the rims being parallel to each other and
Extending perpendicularly to said direction, said connecting element 17; 25; A snap-actuated switch characterized in that it engages to apply said internal force to said blade and to permit angular movement and deflection of said rims 5, 6 when said connecting element is snap-moved by said blade. 2. In the snap-actuated switch according to claim 1, the contact-carrying connecting element comprises a contact element 17 having a slot 18, the slot decreasing in width from the center to both ends, into which the cantilever arm is attached. A snap actuated switch characterized in that said end portions 7 and 8 of said end portions 3 and 4 engage with each other, and angular movement of said end portions is permitted about the edges of said end portions that engage with both ends of said slot. . 3. In the snap-operated switch according to claim 2, the slot 18 is defined by a plurality of flat surfaces converging from the center toward both ends,
Snap actuated switch, characterized in that both ends of the slot are always engaged with the ends 7, 8 of the blade, regardless of the position of the contact element. 4. The snap operating switch according to claim 2 or 3, wherein the contact element 17 has a clearance between the rims 5 and 6 of the blade. . 5. In the snap-operated switch according to any one of claims 2 to 4, in which the contact element cooperates with a fixed contact, the free ends of the arms 3, 4 and the A snap-actuated switch characterized in that the play between the contact element 17 and the fixed contact 23 momentarily increases the contact pressure between the contact element 17 and the fixed contact 23 immediately before the contacts are separated by the snap-actuation. 6. In the snap-actuated switch according to claim 1, the contact-carrying connecting element 31 is arranged in the hole 18.
in which the free ends of said cantilever arms 3, 4 are freely engaged, said coupling element being part of or connected to said conductive cantilever arm 30; When the blade 1 snaps, the conductive cantilever arm 30
A snap-actuated switch characterized in that it produces a snapping movement of a contact 27 carried by the switch. 7. In the snap-actuated switch according to claim 1, said contact-carrying connecting element 25 is attached to said ends 7, 8 by a rivet 28 passing through said connecting element, said connecting element 25 having said blade attached thereto. A snap-actuated switch characterized in that it is provided with a raised flange 26 which engages the lateral outer edges of the respective ends 7, 8 of both arms.