The invention relates to a screwless terminal, in particular a series terminal, comprising an insulation displacement contact that is positioned inside a terminal housing for a conductor rail and is connected electrically conducting to this conductor rail. The electrical conductor can be inserted into the terminal housing via a feed-through in the housing and can be contacted between the opposite arranged cutting edges of this displacement contact.
A plurality of terminal embodiments for contacting and connecting electrical conductors are known, the so-called series-connected terminals, which can be snapped onto support rails or top hat rails. A distinction can be made between screw terminals, for which the electrical conductors are secured by means of clamping screws, and screwless terminals in the form of spring terminals, for which the electrical conductors are contacted through the clamping on of a pressure or tension spring. Whereas the conductor end to be contacted with the aforementioned screw terminals and the spring terminals is first stripped of insulation, so-called insulation displacement terminals or insulation displacement contacts permit a contacting of the conductor without stripping the insulation. Screwless terminals are generally used for contacting the conductor without stripping the insulation.
A screwless terminal using the insulation displacement technique is thus known from European Reference EP 0 691 706 B1, for which the conductor is moved with a translational movement and by means of an auxiliary element against an insulation displacement contact with blade-type cutting contacts. These cutting contacts penetrate the conductor insulation and make contact with the conductor core. The disadvantage of this terminal embodiment is that the openings for inserting the conductor on the one hand and those for the auxiliary element on the other hand are provided on different sides of the terminal housing. In many application cases, this makes the assembly and contacting of the conductor considerably more difficult.
This problem is avoided with a screwless terminal known from German Reference 195 41 137 A1, designed as electrical front wiring terminal, in that an insulation displacement contact positioned inside the terminal housing is pivoted with an actuation tool in a rotating movement against the conductor. This actuation tool is inserted into the terminal housing via the same housing side as the conductor. The disadvantage of this embodiment on the one hand is that the unsatisfactory electrical connection between the insulation displacement contact and the conductor rail connected thereto since this connection simultaneously represents the pivoting joint. Thus, only a practically point-shaped connection can be realized with simultaneous forced weakening of the conductor rail cross section. On the other hand, it is made considerably more difficult to detach the insulation displacement contacting.
Thus, it is the object of the invention to modify a screwless terminal of the aforementioned type, so as to permit a reliable insulation displacement contacting of a conductor while avoiding the aforementioned disadvantages and, at the same time, ensure an easy detachability.
This object is solved according to the invention with the features in claim 1. For this, the insulation displacement contact is arranged so as to be displaceable on the conductor rail. With an immovably positioned conductor, the insulation displacement contacting occurs through a translational sliding movement of the insulation displacement contact along the conductor rail. In the process, opposite arranged cutting edges of the insulation displacement contact cut through the conductor rail insulation by forming a guide and cutting slot and make contact with its conductor core.
The insulation displacement contact has a U-shaped design in order to form the cutting edges, wherein the free ends of the U-shaped legs are bent toward each other to create the cutting and guide slot. The front edge of the insulation displacement contact, meaning of the cutting slot, which faces the conductor if the conductor is inserted into the terminal housing, in that case extends downward at a slant and has a scarfed design.
To be sure, the insulation displacement contacting disclosed in German References DE 298 02 674 U1 and DE 197 49 622 C1 is realized with the aid of a sliding carriage moved with a translational movement. However, the sliding carriages, made of insulating material for the known terminals, must be inserted as additional parts from the outside into the terminal housing or must be moved with a sliding movement on the inside of the housing. In addition, both these embodiments have the disadvantage that the conductor is moved together with the slider in the direction of an insulation displacement contact that is locally fixed inside the terminal housing, so that it can be inserted into its cutting slot.
Starting with this known sliding techniques, the invention is based on the concept that the number of components necessary for the insulation displacement contacting of the conductor can be reduced by moving the insulation displacement contact itself in a translational movement along the conductor rail. As a result, the insulation displacement contacting can occur while the conductor is simultaneously in the resting position, meaning it is immobile. In turn, this permits a particularly reliable and secure positioning and holding of the conductor during the insulation displacement contacting.
The conductor, advantageously positioned rigid and thus immovable inside the terminal housing, is held inside a sleeve-shaped guide following its insertion into the terminal housing and prior to the actual insulation displacement contacting. Above the cutting edges, this sleeve-shaped guide is formed by the housing feed-through and below the cutting edges by guide bars formed onto the insulation displacement contact and extending in longitudinal direction of the rail. These guide bars fit against the conductor prior to the insulation displacement contacting and thus hold the conductor between them.
The electrically conducting connection between the insulation displacement contact and the conductor rail can occur in different ways. The connection for one particularly preferred embodiment occurs by means of a sliding coupling that is formed below one front edge of the insulation displacement contact onto this contact and extends in longitudinal rail direction. The sliding coupling in the process is bent upward against an inward-bent conductor rail section, such that it fits against the underside of the conductor rail section. The bent-in conductor rail section of one useful modification of this embodiment has a free end, bent upward in the direction of the housing feed-through. On the back, meaning on the conductor side facing away from the insulation displacement contact, the free end functions as supporting web for the conductor.
According to an alternative embodiment, a sliding contact on the side is used to establish the electrically conducting connection between the insulation displacement contact and the conductor rail. The insulation displacement contact preferably has two sliding couplings for this, which fit against the opposite-arranged side edges of the conductor rail. With this embodiment, the conductor rail advantageously has a narrowed-down design in the sliding contact region, so that the sliding couplings that are preferably curved inward in the direction of the conductor rail do not or only insignificantly project on the side over the conductor rail.
The electrically conducting connection of another embodiment occurs with a lower and/or upper sliding contact, relative to the conductor rail. For this, a sliding coupling that is formed onto the insulation displacement contact fits against the conductor rail underside, against the conductor rail top, or against both sides of the conductor rail. The sliding coupling formed onto the insulation displacement contact in this case is bent toward the inside, transverse to the longitudinal direction of the rail. For the top and bottom contacting, this sliding coupling, starting from the underside of the conductor rail, is bent over at the top and thus fits with the free end against the conductor rail top while encompassing the conductor rail.
The electrically conducting connection between the insulation displacement contact and the conductor rail furthermore can occur with a sliding contact provided in the center region of the conductor rail. For this, a sliding coupling fits against a contact coupling that is formed onto the conductor rail, which sliding coupling is positioned against the contact coupling and, in turn, is formed onto the insulation displacement contact. This embodiment advantageously has two sliding couplings that accommodate the contact coupling for the conductor rail between them and are formed onto the insulation displacement contact. These sliding couplings are bent inward in the direction of the conductor rail center and fit against the upward bent contact coupling of the conductor rail.
To form the contact coupling, a widened conductor rail section can be slotted on both sides, transverse to the longitudinal rail direction, and can subsequently be bent upward. An alternative method of forming the contact coupling, provides for a conductor rail section that has been bent to an upright position by bending it several times and is aligned parallel to the longitudinal rail direction by subsequently twisting or turning it.
Terminals of this type use the insulation displacement technique to cut the insulation and contact the conductor. An actuation tool, such as a screwdriver that can be inserted from the outside into the terminal housing, is generally provided to supply the necessary force. The screwdriver is used to move the conductor and insulation displacement contact relative to each other. For that reason, the insulation displacement contact has an insertion opening or insertion slot for the conductor and an engagement recess for an actuation tool, which are advantageously arranged successively in movement direction. A funnel-shaped housing well in the terminal housing is aligned with this engagement recess, which can have a dovetailed design. An actuation tool can be inserted via this well from the outside into the terminal housing. The funnel-shaped housing well is tapered in insertion direction. However, below the narrowed section or necking, formed in the process, this well conically expands again in the direction of the engagement recess.
For a particularly advantageous embodiment that also permits a careful handling, an actuation element that operates jointly with the actuation tool is activated for contacting the conductor. The actuation element is designed such that a direct contact is avoided between the actuation tool and the contacting element. For a secure insulation displacement contacting, it is therefore provided that the contacting element encompasses the insulation displacement contact for contacting the conductor, which is held locally fixed inside the terminal housing. The contacting element and the insulation displacement contact thus form a single structural component.
The advantage of the embodiment with the additional actuation element is that the contacting element, for example, cannot be damaged due to an improper insertion of the actuation tool. As a result, a careful actuation is ensured, so that the functional ability of the insulation displacement contact is maintained even with repeated conductor contacting. If the actuation tool is inserted, the actuation element is preferably arranged between this tool and the contacting element.
The actuation element, which is provided with a holding space for the actuation tool, is hollow on the inside and forms a multi-sided guide for the actuation tool. As a result, a direct contact between the actuation tool and the contacting element is avoided, even when disconnecting the contact, meaning with different movement directions of the actuation tool. The actuation tool in that case preferably engages in the contacting element. The loose engagement on the one hand permits a secure guidance of the actuation tool and, on the other hand, ensures an easier handling due to the play. For this, the actuation element preferably is arranged securely inside the terminal housing, so as to avoid the loss of the actuation element.
The housing for one advantageous modification is provided with a projection as support for the actuation element and the actuation element snaps into this support. This arrangement permits an especially easy installation of the actuation element in the terminal housing, in that the actuation element is pushed into the terminal housing via a pressure point determined by the projection. The projection in this case can define a rotational axis for the actuation element. Since the actuation element simultaneously guides the actuation tool, this tool is also rotated around this axis. The projection designed as support thus forms a point of engagement on which the actuation tool is supported. As a result, the terminal housing advantageously absorbs the forces exerted by the actuation tool.
If the actuation element is designed as pivoting lever, in particular having a wedge-shaped convexity as counter-support for the support, an easy insertion of the actuation element into the terminal housing is possible. The actuation element preferably has an elastic design to permit an easy insertion via the projection. The actuation element is preferably designed as one piece to ensure a simple design with respect to production technology.
To make the terminal highly operator-friendly, the actuation element advantageously is provided with a display indicating the movement direction for the open position and the clamping position. As a result, it is easy to see from the outside in what direction the actuation tool must be guided for a clamping contact or to disconnect the contact. One preferred embodiment of the actuation element furthermore is provided with a marking for the contacting element position, so as to be highly operator-friendly and to detect if the inserted conductor is contacted.