DE20208724U1 - Spring terminal for electric conductor, has C-shaped main spring having basic limb and two lateral limbs - Google Patents

Abstract

A spring-terminal (1) has a clamp cage (5) exerting a current-conducting action having two open sides (13) one for insertion of the conductor. At least one or more springs (7) are positioned in the cage for clamping the conductor (3) via actuating lever (9). The spring (7) is C-shaped and has at least one basic limb and two lateral limbs, and a freely movable pressing-edge on one of the lateral limbs directed against the direction of insertion of the conductor and for pressing the conductor in the clamping space. The C-shaped spring (7) is arranged in the cage (5) so that the clamping space is cleared by actuating the lever (9) and pressing the basic limb of the spring (7).

Description

Spring clamp

The invention relates to a spring terminal for connecting a conductor, with a clamping cage that performs a current-conducting function with an at least partially open front side for inserting the conductor and at least one or more springs arranged in the clamping cage for clamping the conductor in the clamping cage between the spring and the inner wall of the clamping cage, wherein the at least one spring is assigned an actuating lever.

DE 196 14 977 discloses a spring clamp in which a lug - a type of tab - serves as protection against overstretching of the spring and at the same time as an actuating lever and is formed integrally with the spring. The spring clamp is actuated using a screwdriver, which is used to open the spring from the direction in which the conductor is inserted.

A spring clamp of this type is known from DE 201 17 770 Ul. The spring clamp known from this document has proven itself, but it should be further developed in

LOESENBECK · STRACKE · SPECHT · DANTZ - PATENT ATTORNEYS - EUROPEAN P,

Registration text from 27.05.2002 Page

their structure can be simplified in order to reduce the manufacturing costs of the spring terminal and yet maintain or improve the functional reliability of the spring terminal, particularly with regard to ever smaller designs. The generic spring terminal, like the spring terminal according to the invention, is particularly suitable as a fully SMT-capable circuit board connection element.

Against the background of this state of the art, the object of the invention is to realize a cost-effectively producible spring clamp with a particularly simple and yet functionally reliable structural design, which is particularly well suited for the design of spring clamps with small dimensions.

The invention solves this problem by the subject matter of claim 1.

According to this, the at least one spring has a C-shaped geometry with a base leg and two side legs and with a freely movable contact edge aligned against the conductor insertion direction on one of the side legs for pressing the conductor in the clamping space against the inner wall of the clamping cage and with an anchoring means for anchoring the spring in the clamping cage, wherein the at least one C-shaped spring is arranged in the clamping cage in such a way that it releases the clamping space when the actuating lever is actuated by exerting tension on one end of the spring and exerting pressure on the longitudinal leg. Also to be mentioned as an advantage is the particularly secure locking or secure holding of the conductor in the clamping space on the contact edge of the clamping spring, which cannot be opened accidentally (e.g. by pulling on the conductor).

Preferably, the actuating lever and the spring form a pre-assembled unit made up of elements that are initially manufactured separately and then connected to one another, which can be inserted into the clamping cage. In particular, the actuating lever is manufactured separately from the spring and then connected to the spring clamp in a form-fitting manner, e.g. by welding or riveting. The separate manufacture of the spring and actuating lever leads to an improved

LOESENBECK · STRACKE · SPECHT · DANTZ - PATENT ATTORNEYS - EUROPEAN PATENT ATTORNEYS

Registration text from 27.05.2002 Page

Manufacturability, because excessive recesses and cutouts in the cutting of the spring and operating lever can be avoided. Such cutouts lead to cross-sectional reductions, which can lead in particular to undesirable weakening, but on the other hand also to undesirable material reinforcements. When the two elements are manufactured separately, on the other hand, the individual elements are cut in exactly the way they are and the connection between the lever and the spring is exactly the way it is best for the given task, especially for clamping springs with small dimensions.

The spring clamp has a simple and cost-effective design due to the use of only a few parts, whereby the actuating lever in turn allows the spring clamp to be actuated "from the outside" parallel to the conductor insertion direction. By actuating the attachment leg on the outside of the housing, it is possible to press the spring leg in the direction of the contact leg and thus open the spring by pulling. The conductor can then be inserted into or removed from the clamp. Rigid conductors can also be inserted using the "push-in" method without actuating the attachment leg.

Preferably, the clamping cage is also provided with surfaces such that automatic assembly (pick and place) is possible.

A further advantage of the invention is that the spring terminal can be used without an insulating housing. However, it is also possible to provide the spring terminal with a simple plastic housing that can be fitted later.

According to a further advantageous variant, two or more springs are arranged in one clamping cage, which further reduces the costs of a corresponding multiple connection spring terminal and ensures a particularly compact, narrow design.

LOESENBECK · STRACKE · SPECHT · DANTZ - PATENT ATTORNEYS - EUROPEAN PATENT AND JR^pf MJ$)& ^TTQRNffiS

Registration text dated 27.05.2002 Page 4

The rigid end of the conductor can also be inserted without tools, without operating the operating lever, provided that the spring is designed accordingly and the conductor has a sufficiently stable dimension.

Advantageous further developments of the invention can be found in the subclaims.

The invention is described in more detail below using exemplary embodiments with reference to the drawing. It shows:

Fig. 1 shows a section through a spring terminal in the unconnected state;

Fig. 2 the spring clamp from Fig. 1 during operation with an actuator

tool;

Fig. 3a, 3b a side view of the spring clamp from Fig. 1 and a detailed enlargement of this side view; and

Fig. 4a-f different views of the spring and the operating lever of the spring clamp from Fig. 1 to 3.

Fig. 1 shows a spring terminal 1 for connecting a conductor 3 (see Fig. 2) with a clamping cage 5 made of an electrically conductive material in which a single (clamping) spring 7 is arranged, to which an actuating lever 9 is assigned. The clamping cage 5 itself takes on a current-conducting function or the function of a busbar.

Both the clamping cage 5 and the spring 7 are each formed in one piece, e.g. as stamped and bent parts made of sheet metal strips with essentially rectangular sections and functional attachments molded onto the rectangular section.

Thus, the clamping cage 5 of Fig. 1 is made from only a single sheet metal strip which is bent into a profile or tube piece with a rectangular cross-section, the ends or end faces 11, 12 of which are at least partially open and of which the upper end face in Fig. 1 forms a conductor insertion opening.

LOESENBECK · STRACKE · SPECHT · DANTZ - PATENT ATTORNEYS - EUROPEAN P^TENT^NDJTR^DJEM^Rfc iTTClRNEYs

Registration text dated 27.05.2002 Page 5

On one open end face 11, three soldering legs 13 are formed or attached to the clamping cage 5 (or the sheet metal strip used to manufacture it), with which the spring clamp 1 can be soldered into/onto a circuit board (not shown here), for example. The soldering legs 13 establish the electrical connection to the circuit board. Due to their arrangement on three different side edges of the clamping cage, they also transfer the forces generated when the spring clamp is actuated directly to the circuit board. They also provide a stand-up for an SMT reflow process.

The spring terminals 1 are designed in such a way that they can be arranged relatively close to one another on the circuit board. If necessary, they can be provided with an outer housing made of insulating material (not shown here) after mounting on the circuit board.

A lock 15 (made of tongue and groove) absorbs the reaction forces caused by spring forces during clamping on the clamping cage 5 in its slotted side wall,
which is created when the clamping cage 5 is bent or rolled and ensures that the clamping cage 5 remains dimensionally stable even under maximum deflection of the spring 7.

The outer surfaces of the clamping cage 5, which is bent into a rectangular box profile, form
flat surfaces, which can be used, for example, for the attachment of suction pipettes for
an automated assembly. In particular, however, a projection 17 is used as the suction surface, which is bent at right angles over a part of the upper front side 11 and closes the upper front side over slightly more than half its width, so
that only a smaller, defined part of the upper front side is open and serves as
conductor insertion opening 19 remains. The attachment is even
bent again slightly into the interior of the terminal in order to further improve the insertion of the conductor 3 into the terminal cage and its guidance in the terminal cage 5.

LOESENBECK · STRACKE · SPECHT · DANTZ - PATENT ATTORNEYS - EUROPEAN PATENT LAWYERS

Registration text from 27.05.2002 Page

For this purpose, the free end 23 can also be anchored with its two side edges by means of pins or the like in recesses 31 (e.g. bores or punched-outs) in the walls of the clamping cage 5.

In the area of the conductor system or the terminal space, embossings 21 can be formed in one of the inner walls of the clamping cage 5, which, due to their geometry and in interaction with a pressure edge of the spring 7, prevent the conductor from being accidentally pulled out of the spring clamp and ensure good conductive contact with the conductor.

In the inner wall of the clamping cage 5 opposite the embossings 21 or the conductor contact surface, a recess or opening 25 is formed through which the actuating lever 9 passes from the inside to the outside and which is dimensioned such that the actuating lever 9 can be pivoted in such a way that the spring 7 opens sufficiently to be able to insert a conductor into the clamping space or conductor connection space between the spring 7 and the inner wall of the clamping cage 5 with the embossings 21 and to be able to release it again from this. To protect the spring, projections 33 formed on the outside of the actuating lever 9 limit the actuation path - they come into contact with the circuit board surface.

The spring 7 - see also Fig. 4 - has essentially the shape of a "C" in cross section with a base leg 7a and two curved side legs 7b and 7c.

The "free" side of the C-shaped spring is oriented towards the conductor contact surface of the clamping cage. The lower side leg 7c has a substantially curved shape. The bend preferably extends over a range of 180°, but can in principle be in a range between 90° and 270°. The area of the bend is followed by an area 7d lying parallel to the base leg 7a, which merges into a bend or locking lug 7e, which rests against the inner wall of the clamping cage 5, which is provided with the embossings 21.

LOESENBECK' STRACKE ' SPECHT» DANTZ - PATENT ATTORNEYS - EUROPEAN P&TENT AW) gR^f M/jRK 4TT(JRJ^y

Registration text from 27.05.2002 Page

Lateral projections 7f, 7g are formed on the sides of the locking lug 7e as anchoring means for the spring in the clamping cage, which engage in V-shaped recesses or V-shaped slots 27 with particularly relatively sharp edges in the side walls of the clamping cage 5 and securely position the spring in the clamping cage 5. 5

Following a first bend of 90°, the upper bent leg 7b has a surface extending at right angles to the base leg 7a and parallel to the front side 11, onto which the actuating lever 9 is placed. The upper leg 7b ends at its free end in a bend in the direction of the lower bent leg 7c, the free end forming a pressing edge 7h for the conductor.

The actuating lever 9 consists of an elongated sheet metal strip section 9a which is placed on the upper leg 7b of the spring 7 and passes through the opening 25 of the clamping cage 5. At its end facing away from the spring, it has a bent end 9b which forms an attachment point for an actuating tool such as a screwdriver. The actuating lever 5 has a right-angled bend 9c with an extension 9d in its area protruding laterally over the spring, which on the one hand stabilizes the actuating lever 5 and on the other hand ensures support on the base leg 7a of the spring 7. It can also be mounted after the spring 7 in the clamping cage 5 and then laser welded to the spring 7.

The function of this arrangement is as follows.

If the free end of the actuating lever is pressed down with a screwdriver 29 parallel to the conductor 3 in the direction of the soldering legs 13 (i.e. in the direction of a circuit board), as can be seen in Fig. 2, the spring 7 opens essentially perpendicular to the forward movement of the screwdriver or to the insertion direction of the screwdriver 29, because the clamping edge 7h is pulled away from the inner wall of the clamping cage 5, whereas the lower end of the spring 7 is pressed by the actuating lever 9 in the direction of this inner wall of the clamping cage 5.

♦ · f J J t,. * I ·

LOESENBECK · STRACKE · SPECHT · DANTZ - PATENT ATTORNEYS - EUROPEAN PATENT LAWYERS

Registration text from 27.05.2002 Page

In this operating position, a conductor 3 can be inserted through the conductor insertion opening 19 into the clamping space between the clamping edge 7h and the inner wall of the clamping cage 5. After loosening the screwdriver 29 and the actuating lever 9, the spring 7 returns to its original position and presses the inserted conductor 3 against the embossings 21. This creates a conductive connection between the conductor 3 and the clamping cage 5. The clamping edge 7h, which is directed against the conductor insertion direction, secures the conductor 3 against being accidentally pulled out of the clamping point.

The actuating lever 9 therefore does not restrict the clamping space of the spring 7 and does not hinder the introduction of the conductor 3 into the clamping space or into the clamping point. The actuating lever 9 is advantageously designed in such a way that the bending moment is introduced in the upper area of the spring in the form of a tensile force and in the lower area of the spring by a compressive force.

Even conductors with a small cross-section are reliably contacted, since the spring 7 is designed in such a way that the clamping edge 7h pressing the conductor presses these conductors (e.g. sensor conductors) tangentially and conductors with a larger cross-section with the cutting-like clamping edge 7h against the inner wall of the clamping cage 5.

Overloading of the spring is reliably prevented by the limited pivotability of the actuating lever 9 in the recess 25 and/or limiting lugs provided on the outside of the lever 9.

The actuating lever 9 and the spring 7 are manufactured separately and then connected to one another by means of a welding process or another joining process to create a positive connection. Due to its pre-tension, the spring 7 anchors itself automatically in the clamping cage 5.

The spring is attached solely by means of leg 7d and/or attachment or locking lug 7e.

LOESENBECK · STRACKE · SPECHT · DANTZ - PATENT ATTORNEYS - EUROPEAN PATENT ^NDJTR/JDfM

t· ·♦•♦ · « » · ♦

Registration text dated 27.05.2002

The spring is pushed from below into a recess in the clamping cage until the projection 7d snaps into the recess (slot 27). The spring hangs on this fastening even without pre-tension.

LOESENBECK · STRACKE · SPECHT · DANTZ - PATENT ATTORNEYS - EUROPEAN INTERNATIONAL TRADE

et» *i ""

♦ · ♦

Notice dated 27.05.2002

Reference symbol 1 Spring clamp 3 Director 5 Clamping cage 7 Feather 7a Base leg 7b and 7c Side legs 7d Area 7e Bending 7f,7g Projections 7h Pressure edge 9 Operating lever 9a Sheet metal strip section 9 curved end 9c Bending 9d Extension 11,12 Front sides 13 Soldering legs 15 Lock 17 Approach 19 Conductor insertion opening 21 Embossings 23 free end 25 breakthrough 27 Slots 29 screwdriver 31 Recesses 33 approaches

Claims (23)

1. Spring terminal ( 1 ) for connecting a conductor ( 3 ), with - a clamping cage ( 5 ) performing a current-conducting function with at least one, preferably two at least partially open end faces ( 11 , 13 ), one of which forms a conductor insertion opening ( 19 ) for inserting the conductor, - at least one or more springs ( 7 ) arranged in the clamping cage ( 5 ) for clamping the conductor ( 3 ) in the clamping space between the spring ( 7 ) and the inner wall of the clamping cage, - wherein the at least one spring ( 7 ) is associated with an actuating lever ( 9 ), characterized in that 1. the at least one spring ( 7 ) has a C-shaped geometry with at least one base leg ( 7a ) and two side legs ( 7b , 7c ) with a freely movable pressing edge ( 7d ) aligned opposite to the conductor insertion direction on one of the side legs ( 7b ) for pressing the conductor in the clamping space against the inner wall of the clamping cage ( 5 ) and with an anchoring means for anchoring the spring ( 7 ) in the clamping cage ( 5 ) on the other side leg ( 7c ), - wherein the at least one C-shaped spring ( 7 ) is arranged in the clamping cage ( 5 ) in such a way that it releases the clamping space when the actuating lever ( 9 ) is actuated by exerting tension on one end of the spring ( 7b ) and exerting pressure on the base leg 7a ). 2. Spring clamp according to one of the preceding claims, characterized in that the actuating lever ( 9 ) and the spring ( 7 ) form a pre-assembled unit from elements which are initially manufactured separately and then connected to one another, which can be inserted into the clamping cage. 3. Spring clamp according to one of the preceding claims, characterized in that the actuating lever ( 9 ) is only connected to the clamping spring, e.g. by laser welding, after the clamping spring ( 7 ) has been mounted in the clamping cage ( 5 ). 4. Spring terminal according to one of the preceding claims, characterized in that the clamping cage ( 5 ) consists of a sheet metal strip which is bent into a profile piece with a rectangular cross-section and two opposing end faces ( 11 , 12 ) which are open at least in sections, one of which forms a conductor insertion opening ( 19 ) and soldering legs ( 13 ) are formed on the other end face. 5. Spring clamp according to one of the preceding claims, characterized by a lock ( 15 ), in particular made of tongue and groove, in the slotted side wall of the clamping cage ( 5 ). 6. Spring clamp according to one of the preceding claims, characterized in that a projection ( 17 ) is bent at a right angle over a part of the upper end face ( 11 ) of the clamping cage ( 5 ) and closes the upper end face in sections. 7. Spring clamp according to one of the preceding claims, characterized in that a free end ( 23 ) of the projection ( 17 ) is bent inwards into the clamping cage ( 5 ) and forms a stop there for the actuating lever ( 9 ). 8. Spring clamp according to one of the preceding claims, characterized in that the free end ( 23 ) is anchored at its side edges by means of pins as anchoring means in the inner walls of the clamping cage ( 5 ). 9. Spring clamp according to one of the preceding claims, characterized in that clamping contours such as embossings ( 21 ) are formed in the region of the conductor contact surface of the clamping cage. 10. Spring clamp according to one of the preceding claims, characterized in that a recess ( 25 ) is formed in the clamping cage, through which the actuating lever ( 9 ) passes from the inside to the outside and which is dimensioned such that the actuating lever ( 9 ) can be pivoted so that the spring ( 7 ) opens sufficiently to introduce a conductor into the clamping space between the spring ( 7 ) and the inner wall of the clamping cage ( 5 ). 11. Spring clamp according to one of the preceding claims, characterized in that the C-shaped spring ( 7 ) has a base leg ( 7a ) and two bent side legs ( 7b and 7c ), the "free" side of the C-shaped spring being directed towards the conductor contact surface of the clamping cage ( 5 ). 12. Spring terminal according to one of the preceding claims, characterized in that the side leg (7c) facing away from the conductor insertion opening ( 19 ) has a substantially curved shape, the bend extending over 180° and the region of the bend being followed by a region ( 7d ) lying parallel to the base leg ( 7a ), which merges into a locking lug ( 7e ) which is provided for locking the spring in the clamping cage. 13. Spring clamp according to one of the preceding claims, characterized in that the side leg (7c) facing away from the conductor insertion opening ( 19 ) has a substantially curved shape, the bend preferably extending over a range between 90° and 270°, and the region of the bend is followed by a region ( 7d ) lying parallel to the base leg ( 7a ), which merges into a locking lug ( 7e ) which is provided for locking the spring in the clamping cage. 14. Spring clamp according to one of the preceding claims, characterized in that lateral projections ( 7 f, 7 g) are formed on the sides of the locking lug ( 7 e) as anchoring means, which engage in V-shaped recesses or slots ( 27 ) in the side walls of the clamping cage ( 5 ) and securely position the spring in the clamping cage ( 5 ). 15. Spring terminal according to one of the preceding claims, characterized in that the upper bent leg ( 7 b) ends at its free end in a bend in the direction of the lower bent leg ( 7 c), the free end forming a pressing edge ( 7 h) for the conductor. 16. Spring clamp according to one of the preceding claims, characterized in that the actuating lever ( 9 ) consists of an elongated sheet metal strip section ( 9a ) which passes through the opening ( 25 ) and has a bent end ( 9b ) at its end facing away from the spring ( 7 ), which forms an attachment possibility for an actuating tool such as a screwdriver ( 29 ). 17. Spring clamp according to one of the preceding claims, characterized in that the actuating lever ( 9 ) has, in its region projecting laterally beyond the spring, a right-angled bend ( 9c ) with an extension ( 9d ) which is supported on the base leg ( 7a ) of the spring ( 7 ). 18. Spring clamp according to one of the preceding claims, characterized in that the actuating lever is provided at its lower end, positioned on the outside of the clamping cage, with a travel limiting projection ( 33 ) which, when actuated, rests on the circuit board surface, for example. 19. Spring clamp according to one of the preceding claims, characterized in that the spring ( 7 ) is designed such that thin conductors such as sensor conductors are pressed tangentially and conductors with a larger cross section are pressed with the cutting-like clamping edge ( 7h ) against the inner wall of the clamping cage 5 . 20. Spring terminal according to one of the preceding claims, characterized in that the clamping cage is designed for mounting an insulating housing. 21. Spring clamp according to one of the preceding claims, characterized in that two or more springs ( 7 , 8 ) are inserted into the clamping cage ( 5 ). 22. Spring clamp according to one of the preceding claims, characterized in that the spring ( 7 ) is pushed into the slots ( 27 ) from below, wherein the locking lugs ( 5 ) engage in the slots ( 27 ). 23. Spring clamp according to claim 1 or 2, characterized in that the spring ( 9 ) has at least one attachment surface ( 17 ) for an automatic assembly system.