Abstract:
A terminal block for high transmission rates in the telecommunication and data technique. The terminal block includes a plastic casing and metal insulation displacement contact elements inserted pair-wise in at least two parallel rows into the casing with connected contact fingers forming spring contacts. The flat insulation displacement contact elements are formed at the narrow side webs including the contact slot therebetween and of the base web. The width of the spring contacts is small.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a terminal block for high transmission rates in the telecommunication and data field or technique, and in particular to a terminal block comprising a plastic casing and metal insulation displacement contact elements inserted pair-wise in at least two parallel rows into the casing with connected contact fingers forming spring contacts. 
     BACKGROUND OF THE INVENTION 
     There is known in the art a terminal block of the type referred to hereinbefore from U.S. Pat. No. 5,160,273. Therein, the problem of crosstalk between adjacent insulation displacement contact elements is intended to be solved by insertion of a plurality of electrically conductive shielding plates between the individual pairs of insulation displacement contact elements. The problem of crosstalk occurs when transmitting high volumes of information over electrical lines and the information is being transmitted at high frequencies. The transmission of such high frequencies will generate a radiation and an interference between adjacent lines, in particular when such lines are closely adjacent to each other in the terminal block. By insertion of the electrically conductive shielding plates, a higher crosstalk attenuation is intended to be achieved. Application of large-surface, electrically conductive shielding plates in the terminal blocks requires, however, an increased constructional size of the terminal blocks and a higher cost when manufacturing the terminal blocks. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     It is therefore the object of the invention to provide a terminal block for the type referred to hereinbefore, for high transmission rates in the telecommunication and data technique, wherein the problem of crosstalk is eliminated or substantially reduced with low expenditure of technical and economical efforts. 
     The solution of this object is achieved, according to the present invention, by that the flat insulation displacement contact elements are formed of very narrow side webs including the contact slot therebetween and of a narrow base web connecting the latter only, and that the width of the spring contacts is as small as possible. By this substantial reduction in size of the insulation displacement contact elements by reducing the surface areas of the insulation displacement contact element as well as of the contact fingers connecting the latter, the capacities between two parallel conductive plates are considerably reduced, thereby a strong crosstalk attenuation or an improvement of the crosstalk values being achieved. This applies for a pair of adjacent insulation displacement contact elements connected with a pair of cable wires as well as for adjacent insulation displacement contact elements connected to different pairs of cable wires. 
     In another embodiment of the present invention, a considerably improved crosstalk attenuation can be obtained by that the spacing of two adjacent pairs of insulation displacement contact elements of a row is larger than the spacing of the two insulation displacement contact elements of a pair. Thereby, the capacities of adjacent pairs of insulation displacement contact elements aligned in a row are further reduced, and the crosstalk values are further improved. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a view of the first embodiment of the terminal block, 
     FIG. 2 is a side view according to FIG. 1. 
     FIG. 3 is a top view according to FIG. 1. 
     FIG. 4 is an individual representation of a pair of insulation displacement contact elements disposed in two opposite rows, in the first embodiment according to FIGS. 1 to 3. 
     FIG. 5 is an enlarged cross-section of the terminal block according to FIG. 1. 
     FIG. 6 is a view of the second embodiment of the terminal block, 
     FIG. 7 is a side view. 
     FIG. 8 is a top view. 
     FIG. 9 is an individual representation of a pair of insulation displacement contact elements disposed in two opposite rows, for the terminal block in the second embodiment according to FIGS. 6 to 8. 
     FIG. 10 is a cross-section of the terminal block along line X--X according to FIG. 6. 
     FIG. 11 is a cross-section along line XI--XI of the terminal block according to FIG. 6. 
     FIG. 12 is a view of the third embodiment of the terminal block. 
     FIG. 13 is a side view. 
     FIG. 14 is a top view. 
     FIG. 15 is a pair of insulation displacement contact elements disposed in two opposite rows, for the terminal block in the third embodiment according to FIGS. 12 to 14. 
     FIG. 16 is a cross-section along line XVI--XVI of the terminal block according to FIG. 12, and 
     FIG. 17 is a cross-section along line XVII--XVII of FIG. 12. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The terminal block according to the first embodiment shown in FIGS. 1 to 5 serves for high transmission rates in the telecommunication and data field and technique. The terminal block 1 comprises a plastic casing 2 composed of an upper portion 3 and a lower portion 4 being latched with each other by latch openings 5 in the upper portion 3 and latch lugs 6 in the lower portion 4. In the upper portion 3 are provided clamping slots 7 with integral clamping lugs 8 and clamping webs 9 serving to receive insulation displacement contact elements 10. 
     As is shown in FIGS. 1 and 2, the spacing (the distance) d between two immediately adjacent clamping slots 7 serving for the insertion of a pair of insulation displacement contact elements 10 is 3 mm and thus substantially smaller than the spacing D of 9.8 mm between two adjacent pairs of clamping slots 7 or insulation displacement contact elements 10 provided therein, resp. This larger spacing D serves to reduce the capacities generated between the insulation displacement contact elements 10 forming condenser plates, in order to improve the crosstalk values and to obtain an improved crosstalk attenuation. 
     The individual insulation displacement contact elements 10 are each formed of, or as, a blade-type material and comprise only two side webs 12 of very narrow construction. The contact elements 10 include a contact slot 11 defined between the two side webs 12 and a narrow base web 13 connecting the two blade-type side webs 12 to each other. The contact slot 11 has a V-shaped introduction area 14 and an oval enlarged end area 28. Upon the base web 13 of the insulation displacement contact element 10 follows one contact finger 15 each, which extends at an inwardly bent off direction approximately at a right angle at the base web 13 and is then transformed into a spring contact 16 located in the area of the center line 17 of the casing 2. By the described construction of the conductive insulation displacement contacts elements 10 can be made from a flat or sheet material, the capacities generated between the two insulation displacement contact elements 10 of a pair aligned in a row are further reduced, and thus the crosstalk values are further improved, so that a very high crosstalk attenuation is obtained even within a pair of insulation displacement contact elements 10. 
     The casing 2 comprises, between the two rows of insulation displacement contact elements 10, a row of insertion openings 18 for plugs 19 serving to interrupt the contact connection between the spring contacts 16. The individual plugs 19 are provided, in their plastic casings, with a web-type latch element 20, which is attached in a rocker-type manner at the casing of plug 19. 
     In order to support the very short, flat insulation displacement contact elements 10 in the casing 2 for the purpose of applying the required connection force, continous support walls 22 forming support webs 21 are provided in the lower portion 4 of the casing 2. The support walls project over the outside walls 23 of the lower portion 4 and form counter-supports for the short insulation displacement contact elements 10. These contact elements are immediately supported in the section bent off by 90° of the contact fingers 15, as is shown in FIG. 4. 
     The lower portion 4 of the casing comprises, according to FIGS. 1 to 3, cable guiding portions 24, 25 and pair-wise disposed latch webs 26, by means of which the terminal block 1 can be latched onto a structure (not shown) of parallel rods. As is shown in FIG. 1 in broken lines, the terminal block 1 can also be latched onto a U-shaped mounting bracket 27, the side walls 28 of which form lugs to latch into the terminal blocks 1. 
     To the insulation displacement contact elements 10 can be connected cable pairs 29 of cable wires having conductor cross-sections of 0.40 to 0.64. Crosstalk attenuation is 42 to 48 dB. 
     The terminal block 31 according to the second embodiment shown in FIGS. 6 to 11 differs from the first embodiment of the terminal block 1 shown in FIGS. 1 to 5 in that a first pair of the insulation displacement contact elements 10 are located in an upper portion 33 of the casing 32 at a deeper position which is vertically below (based on the 
     disposition of the terminal block 31, as shown in FIG. 6); another pair of insulation displacement contact elements 10 of the opposite row. The first pair of insulation displacement contact elements 10 are also positioned vertically to the two laterally adjacent insulation displacement contact elements 10 of the same row. The lengths of the contact fingers 15, 35 are also different as shown in FIG. 9. Crosstalk is here between 46 and 52 dB. 
     In the third embodiment of the terminal block 41 shown in FIGS. 12 to 17, the insulation displacement contact elements 10 of a pair are located on the opposite upper and lower sides of the casing 42 being formed of two nearly identical lower and upper portions 43 and 44, resp. The spacing D between two pairs of insulation displacement contact elements 10 disposed in a row is here 19.5mm. The respective pair of insulation displacement contact elements 10 is provided on the respectively opposite side of the lower or upper portion 43 or 44, resp., of the casing 42, as is shown in the sectional representations according to FIGS. 16 and 17. The construction of the insulation displacement contact elements 10 having contact fingers 15 substantially corresponds to that of FIG. 4, the insulation displacement contact elements 10 for the third embodiment of the terminal block 41 according to FIG. 15 being diametrically offset. The terminal block 41 can be rotated by 180° for wiring the two sides. 
     By the first embodiment according to FIGS. 1 to 5, crosstalk attenuation of approximately -49 dB can be obtained with transmission rates of approximately 100 MHz. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.