INSERT FOR A CONNECTION TERMINAL

Abstract: The insert for a connection terminal for assembling electric wires consists of a closed channel shaped housing (15) performed of a sheet material which is bent and positioned overlapping. A bar (13) of an electrically conducting material is inserted in the housing above the mutually overlapping sheet portions (2, 3) and has bend end flaps (14) positioned in incisions (4, 5) in said sheet portions. Thereby the overlapping sheet portions are securely assembled and the conducting bar (13) provides the necessary conductivity of the insert so that the housing (15) per se may be manufactured of a cheap and strong material, such as iron.

Description: I nsert for a Connection i ermiπal Technical Field The present invention relates to an insert for a connection terminal for assembling electric wires consisting of a housing having a wire accomodating opening and screws inserted in the housing for clamping the wires, wherein the housing is formed by overlapping sheet material which is bent so as to form a closed channel . Background Art For the assembly of power wires it is generally required that the wires are fastened by means of screw connections and that the element transferring the current contains a certain minimum amount of copper (58%) . Consequently, it has been usual hitherto to produce inserts from a brass profile wherein the wire accomodating opening is formed by drilling from both ends and whereupon threaded holes for the screws perpendicularly to the wire opening are performed . However, such an insert is relatively expensive, partly because of the high price of brass , partly because of the relatively slow and consequently expensive drilling operations . It is also known to ' produce inserts of a brass sheet strip which is bent to a^clαsed housing, the ends of the strip overlap- ping each other and being provided with screw holes so that the mutu¬ ally overlapping end portions may be held together by the screws , i n addition to the high material price which also here is very high , it is a disadvantage that the screw holes easily become oval by the tightening of the screws and consequently obstruct a subsequent screwing in and unscrewing . Furthermore, the screws cannot provide a stable assembly of the end portions of the sheet strip . Disclosure of I nvention The object of the present invention is to avoid the said disad ¬ vantages of the prior art constructions, and according to the invention this is obtained by the fact that the sheet material of which the housing is formed , is a mechanical ly strong material such as iron , and that a bar of an electrically conducting material is inserted in the housing above the mutual ly overlapping sheet portions and is in mechanical engagement with said two sheet portions , and that the screw holes are provided in the opposite side of the housing . Thereby the housing per se may be performed of another material than copper or brass , and especially it may be made of iron , as said bar Is sufficient for trans ¬ ferring the current. I n case the housing is made of iron or the li ke material , not only a cheap insert is achieved , but said insert will also a greater strength than if it were made of brass. Consequently, the above problems with an insert of a bent brass sheet do not occur. The mechanical engagement of the bar with the mutually overlapping sheet portions provides an efficient and stable assembly of said parts for which reason the tightening of the screws cannot cause an opening of the housing, and the screw holes remain intact after the tightening of the screws so that a possible subsequent screwing in and unscrewing may be carried out without difficulty. Furthermore, as the manufacture of the insert essentially takes place by means of stamping and bending operations and only to a small degree by means of drilling operations the total manufacturing time is relatively short. An embodiment of the insert according to the invention is charac¬ terized in that the mutually overlapping sheet portions of the housing are provided with incisions one above the other at the ends of the housing , which incisions accαmodate the bent end flaps on the bar. Thereby a safe locking of the mutually overlapping sheet portions solely by simple and quick bending operations is achieved . I n a further embodiment according to the invention the incision of the outer sheet portion are deeper than those of the inner sheet pcr- tϊαn . , and the end /laps of the bar are positioned totally in the incisions of the outer sheet portion . Thereby is achieved that the underside of the insert is plane which is an advantage as the insert is to be posi¬ tioned in an Iπsolatiπg housing of plastics material . In order to avoid that the wire inserted from one end of the hαu- sing fills the whole channel , the housing according to the Invention may have at least one flap which is beπdabie from a side wall into the throu going channel of the housing . Preferably, such flaps are positioned in the middle of the channel and serve as end stops for the wires insert¬ ed . I n order to prevent the screws from destroying the inserted wires when the screws are tightened the insert may be provided with a band shaped wire protector, and according to the invention the side of the housing in which the screw noies are provided, may have laps position¬ ed above the bendabie flaps in order to obtain a secure mounting of the wire protector in a simple way, said laps being adapted to be bent down towards the flaps after the band shaped wire protector has been inserted in the cnannel above the flaps . i n a further embodiment of the Insert according to the invention the bar of an electrically conducting material opposite the screw holes is provided with raised areas positioned pairwise opposite each other whic areas from the opposite edges slope downwardly and inwardly agains the middle of the bar. Thereby is ensured that relatively thin conduc tors which are inserted in the connection terminal , will always be posi tioπed centrally under the screw . Brief Description of Drawings The invention will now be explained in more detail and with refe rence to the drawings In which fig . 1 shows a work piece for manufacturing an embodimen of the insert according to the invention , fig- 2 an electrically conducting bar for mounting in the in¬ sert, fig . 3 a longitudinal section of an insert according to the invention performed of the work piece In fig . 1 , ffiigg .. 4 4 the insert of fig . 3 seen from one end , fig . 5 a cross section along the line V-V in fig . 3 , fig . 6 a cross section along the line V I -VI in fig . 3 , fig - 7 a plane view of the inlay in fig . 3, fig . 3 the insert. of fig . 3 .with a wire protector mounted there- in , and fig . 9 a cross section along the line IX- IX in fig . 8. Modes for Carrying Out the invention I n the drawings fig . 1 il lustrates a work piece 1 stamped out of a steel band which work piece 1 is intended for the manufacture of the insert according to the Invention . The ends 2 and 3 of the work piece are intended for - after bending of the work piece to an essentially rectangular shape - being positioned one above the other and are provided with incisions 4 and 5, respectively, of which the incisions 4 are somewhat deeper than the incisions 5. Furthermore, the work piece comprises a central H -shaped opening S, whereby tongues 7 are formed , the purpose of which wil l be described below . Final ly, the work piece shows a plurality of small circular punchings 8, 9 and 10 and possible punch cuts 11 in connection with the holes 10 whereby flaps 12 are provided . Fig . 2 shows a punched conductor strip or bar 13 of an elec ¬ trical ly highly conducting material such as brass , the ends 14 of said strip or bar having a width which is a little smal ler than the width of the incisions 4 and 5 in the work piece 1 . Figs . 3-7 illustrate the work piece 1 after said work has been bent to a rectangular housing 15. It will be seen that th ends 2 and 3 of the work piece are positioned opposite each other with the end 2 having the deepest Incisions 4 being positioned externally. After bending of the work piece 1 the conductor strip 13, the width o which is slightly smaller than the inner width of the housing 15, is positioned therein, and the ends 14 are then bent outwardly through the incisions 5 in order to abut the lower surface of the end portion 3 in the Incisions 4, as will appear from figs. 3 and 4. Thereby an effi- cϊs rt and stable assembly of the mutually overlappping ends 2 and 3 o the work piece Is achieved, and the lower surface of the insert becomes plane without protruding portions of the flaps of the conductor strip . With the punched out holes 9 as starting point the surrounding material is pulled upwards to form screw holes 18 which are provided with threads. The possibly punched out holes 8 serve to reduce mate- rial accumulation by the pulling up operation , as will appear from fig . 5. The construction hitherto described (without the puπchings S, 10 and 11 ) forms a finished insert which - In the usual way is mounted in a housing of plastics material with screws (not shown) inserted In the screw holes S. Because of the shown bending of the work piece 1 a particularly rigid frame is obtained , when said frame is made of iron or the like material instead of brass , and, furthermore, It is avoided that the screw hole becomes ovai and the pressure against the double bottom deriving from the tightened up screw cannot press the mutually over- lapping ends 2 and 3 from one another as a consequence of the locking by means of the conductor strip 13, 14 which is not influenced thereby. By use of the insert the screws press the inserted wires against the conductor strip 13 which strip thus provides the necessary electrical conductivity of the insert. Figs . 4-5 show the squares or flaps 12 which are formed by means of the punched cuts 11 in fig . 11 , in an impressed position , seeing tha they are bent Inwardly crosswise in the insert by swinging around a line which connects the punched out holes 10, which only serve to facilitate the bending of the flaps . Thereby the wire mounting is facifi- tated as the flaps serve as stops, so that the whole wire hoie is not filled up by one wire. In order to prevent tnat a conductor whicn is thin relative to the Inner width of the Insert positions Itself in one side of the terminal , so :hat the screw gets a poor engagement with the conductor and thereb y easier will cause a damage thereto, the bar 13 may - as shown in dotted lines in figs . 2, 3 and 5 - be provided with raised areas 18 positioned pairwise opposite the screw holes which areas 18 for example may be performed as semiconical pulled up areas which extend inwardly against the middle of the bar from the sides of the bar. I n this case the con¬ ductor will always be positoned central ly under the screw. In order to secure an easy insertion of the conductor In the terminal the said pulled up areas are to be carried out with an approximately even rise in the inserting direction of the conductor . Figs . 8 and 9 illustrate a wire protector 17 inserted in the insert which wire protector may be used in order to prevent that the screws upon the tightening up thereof pinch thin or otherwise weak wires apart or deform them too much . The wire protector Is formed of a thin sheet, e. g . of stainless spring steel , and is inserted above the inward - ly folded flaps 12 and deformed over the upper edge of the flaps as shown in fig . 8 by means of a tool inserted through the punching 6 so that said wire protector cannot be displaced from its position when the flaps 7 are bent downwardly as shown in fig. 9.

Claims: CLA IMS : 1 . Insert for a connection terminal for assembling electric wires consisting αf a housing having a wire accomodating opening and screws inserted in the housing for clamping the wires, wherein the housing is formed by overlapping sheet material which is bent so as to formed a closed channel , characterized in that the sheet material of which the housing is formed is a mechanically strong material such as iron, and that a bar (13) of an electrically conducting material is inserted in the housing (15) above the mutually overlapping sheet portions (2, 3) and is in mechanical engagement with said two sheet portions, and that the screw holes (16) are provided in the opposite side of the housing . 2. Insert according to claim Λ , characterized in that the mutually overlapping sheet portions (2, 3) of the housing are provided with incisions (4, 5) positioned one above the other at the ends of the housing which incisions accomodate the bent end flaps (14) on the bar (13) . 3. I nsert according to claim 2, characterized in that the incisions (4) of the outer sheet portion (2) are deeper than the incisions (5) of the inner sheet portion (3) , and that the end flaps (14) of the bar ' are positioned totally In the incisions (4) of the outer sheet portion . 4. Insert according to any of the preceding claims, characterized i that the housing (15) comprises at least one flap (12) which Is bendable from a side wall Into the throughgoing channel of the housing . 5. I nsert according to claim 4 and having a band shaped wire protector (17) , characterized in that the side of the housing in which the screw holes (IS) are provided, have laps (7) positioned above the bendabie flaps (12) said laps (7) being adapted to be bent down to¬ wards the flaps after the band shaped wire protector (17) has been Inserted in the channel above the flaps . 6. I nsert according to any of the preceding claims , characterized i that the bar (13) of an electrically conducting material opposite the screw holes (IS) is provided with pairwise raised areas (18) positioned pairwise opposite each other which areas (13) from the opposite edges slope downwardly against the middle αf the bar . ■ -- '

Inventors: MALMROS FINI
Applicants: CONBLOCK APS
Application year: 1981
Main classification: H01R4
IPC codes: H01R4