EP0514924A1 - Vis de contact - Google Patents

Vis de contact Download PDF

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Publication number
EP0514924A1
EP0514924A1 EP92108684A EP92108684A EP0514924A1 EP 0514924 A1 EP0514924 A1 EP 0514924A1 EP 92108684 A EP92108684 A EP 92108684A EP 92108684 A EP92108684 A EP 92108684A EP 0514924 A1 EP0514924 A1 EP 0514924A1
Authority
EP
European Patent Office
Prior art keywords
contact
screw
contact screw
shaft
screw according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP92108684A
Other languages
German (de)
English (en)
Other versions
EP0514924B1 (fr
Inventor
Georg Czernek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arcus Elektrotechnik Alois Schiffmann GmbH
Original Assignee
Arcus Elektrotechnik Alois Schiffmann GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Arcus Elektrotechnik Alois Schiffmann GmbH filed Critical Arcus Elektrotechnik Alois Schiffmann GmbH
Publication of EP0514924A1 publication Critical patent/EP0514924A1/fr
Application granted granted Critical
Publication of EP0514924B1 publication Critical patent/EP0514924B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
    • H01R4/24—Connections using contact members penetrating or cutting insulation or cable strands
    • H01R4/2475—Connections using contact members penetrating or cutting insulation or cable strands the contact members penetrating the insulation being actuated by screws, nuts or bolts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
    • H01R4/28—Clamped connections, spring connections
    • H01R4/30—Clamped connections, spring connections utilising a screw or nut clamping member

Definitions

  • the invention relates to a contact screw for contacting insulated electrical lines or cables in a terminal, with a screw body with a cylindrical shaft with an external thread; with a screw-in part at the front end of the contact screw, which has clearing devices for cutting through and clearing away insulating material and a contact piece for contacting the conductor material; and with an engagement part in the rear area of the contact screw, in particular an inner edge or outer edge for attaching a tool.
  • contact screws For connecting and contacting insulated electrical lines or cables, contact screws have been used for many years, which have clearing devices in the form of milling devices on their end faces, which come into engagement with the respective conductor, which can in particular be slit-shaped. These slots are expediently arranged obliquely both with respect to the axis of the contact screw and with respect to a cross-sectional area of the contact screw and form sharp-edged cutting edges.
  • such a contact screw is screwed in a little further, whereby further material is removed from the conductor from the cutting edges of the broaching devices until a circular contact surface is worked out in the conductor which corresponds to the diameter of the contact screw.
  • the surface of the respective conductor at the contact point is adapted to the shape of the screw end with a loss of cross section.
  • the lines to be contacted are conductors made of solid or compacted multi-wire material, there are generally no major problems.
  • the fitter easily notices when the contact screw has cut through the insulating material and has come into engagement with the conductor material, because then the mechanical resistance increases considerably when the contact screw is screwed in.
  • the required torque increases, he will only make a predetermined number of revolutions of the contact screw or heed the specified maximum torque in order to ensure reliable contact over a maximum cross-sectional area.
  • the object of the invention is therefore to provide a contact screw for contacting insulated electrical lines or cables in a terminal, which enables simple and reliable mounting even when the conductors to be contacted are made of soft material or multi-wire conductors that are only weakly stranded, consist.
  • the solution according to the invention consists in designing a contact screw of the type mentioned at the outset so that the screw body has a circumferential annular groove which between the shaft and the screw-in part forms a transition region of the screw-in part with a reduced outside diameter, and that the shaft has an axially extending inner bore , which extends to close to the transition area and whose inner diameter is at least as large as the outer diameter of the transition area.
  • the special structure of the contact screw according to the invention advantageously ensures that a predetermined breaking point is formed between the transition region and the shaft of the contact screw, at which the material breaks between the screw-in part on the one hand and the shaft on the other hand when the axial pressure and frictional resistance acting on the screw-in part exceed the specified values.
  • the shaft then acts as a propulsion piston which presses the engagement part in the axial direction against the conductor to be contacted, the screw part then no longer performing a rotary movement. Only the shaft of the contact screw located in the forward direction of rotation rotates, while the front end of the contact screw in the form of the screw-in part stands still and is pressed against the material of the conductor.
  • the tearing off of the screw-in part from the screw body is very easy to determine, on the one hand by a clearly audible cracking, on the other hand by a very sharp drop in the tightening torque, because the actuated shaft of the contact screw then has a much lower mechanical resistance because the resistance of the screw-in part is eliminated until the front of the shaft is screwed in further and comes into mechanical engagement with the back of the screw-in part.
  • the screw-in part is designed as a cylindrical solid part, the transition region of which is rotationally symmetrical and can be received in the inner bore of the shaft.
  • the screw-in part thus forms a particularly effective, mechanically robust contact piece for producing the desired contact.
  • the inner bore of the shaft then forms a guide for the transition region of the screw-in part which, after tearing off, is pushed into the interior of the shaft when the shaft is screwed in further by actuation with the tool.
  • the screw-in part has an external thread in its rear area which corresponds to the external thread of the shaft. In this way, the screw-in part is threadedly engaged in the clamp during its advancing movement.
  • the screw-in part as a contact piece on has a contact plate, the contact diameter of which is larger than the outer diameter of the screw body. This creates a particularly good, large-area contact between the conductor to be contacted and the contact screw. In addition, the frictional resistance between the screw-in part and the conductor to be contacted can thereby be increased, so that timely tearing off of the screw-in part is ensured without causing undesirable damage to the conductor to be contacted.
  • the mutually opposite surfaces of the annular groove run essentially parallel to one another. This ensures that, after the predetermined breaking point has been torn off, a pressure which is as uniform as possible is exerted by the shaft of the contact screw on the screw-in part arranged in front of it in the direction of advance in order to press it against the conductor to be contacted.
  • the contact piece or the contact plate has a flat contact surface on the front which runs essentially parallel to the opposite surfaces of the annular groove. In this way, particularly good contacting of the contact screw is ensured and, moreover, that tilting between the screw-in part on the one hand and the shaft of the contact screw on the other hand is avoided.
  • the contact screw according to the invention has a particularly simple structure, since the machining of the inner bore results in such an internal edge, in particular an internal hexagon, which is used for mounting the contact screw.
  • a lubricant is applied to the surfaces of the annular groove. This advantageously means that after the predetermined breaking point has been torn off, lubricant is present between the two opposite end faces of the screw-in part on the one hand and the shaft on the other hand. This ensures that, in the desired manner, after the predetermined breaking point has been torn off, the screw-in part is actually only pressed against its contact piece without the screw-in part being taken along by the shaft of the contact screw in the direction of rotation.
  • the rear end of the contact screw in the cylindrical shaft has a weakening zone in the circumferential direction, so that the rear end behind this weakening zone forms a tear-off head which breaks off when a predetermined torque is exceeded when the contact screw is tightened. In this way it is ensured that a correct contact with the desired contact pressure is achieved.
  • the weakening zone is dimensioned such that the tear-off head only breaks off when the torque is substantially greater than the torque which is sufficient for breaking at the front predetermined breaking point.
  • the contact screw in the area of the tear-off head in the vicinity of the weakening zone it has at least one protrusion projecting transversely into the interior of the inner edge.
  • This projection in the interior of the inner edge forms a support for the tool to be used and at the same time a lock that reliably prevents the tool from being used too far. If the tear-off head is sheared off, the protrusion protruding into the inner recess is at the same time removed, since it is located in the region of the tear-off head. As a result, the axially adjoining inner edge is freely accessible again, so that such a contact screw can optionally be loosened by a new attachment of the tool.
  • the respective projection is arranged in the extension of a radially extending recess and is designed as a projection protruding radially inwards, impressed or pressed in from the outside.
  • a projection can be produced in a simple manner with a punching tool or with a punch.
  • the radially extending recess can advantageously serve as a guide for the respective tool in order to produce such a projection.
  • the projection is designed as a pin which extends across the wall of the tear-off head and which extends at least partially radially into the interior of the inner edge.
  • the pin will extend through a corresponding radially extending recess and completely or partially penetrate the interior of the inner edge in the radial direction.
  • the weakening zone is designed as a circumferential shearing groove which forms the rear end of the external thread.
  • the respective projection can thus be formed in an insensitive region of the contact screw.
  • the provision of such a shear groove facilitates the formation of the external thread.
  • a contact screw 10 has a screw body with a cylindrical shaft 12, which has an external thread 14, and a screw-in part 16, which has a cylinder part 32, which forms a continuation of the cylindrical shaft 12. Accordingly, its external thread 18 is dimensioned in the same way as the external thread 14.
  • a contact piece 28 can be seen, which is designed in the manner shown as a contact plate, the contact diameter D3 of which can be dimensioned substantially larger than the outer diameter D4 of the shaft 12 or of the cylinder part 32.
  • broaching devices in the form of milling slots 42 are evenly distributed over the circumference. which have an inclination both with respect to the radii of the contact plate 28 and with respect to the axis X of the contact screw 10, in order to work in a manner known per se as cutting edges and to scrape off the insulating material from electrical lines.
  • the contact screw 10 has at its front end a flat contact surface 30 which merges with a sharp edge 29 into a peripheral wall 31 of the contact piece 28.
  • This contributes to the fact that a sharp-edged cutting edge is formed between the milling slots 42 and the contact surface 30 on the one hand and the peripheral wall 31 on the other.
  • the milling slots 42 expediently extend from the peripheral wall 31 to almost the center of the circular contact surface 30 by one to ensure large-scale removal of material through the contact screw 10.
  • a circumferential annular groove 20 is incorporated, which leaves a transition region 26, which has a reduced outer diameter D1 compared to the outer diameter D4 of the shaft 12 and the cylinder part 32.
  • This inner bore 34 In the axial extension of the transition part 26 there is an inner bore 34 extending in the axis, the conical or flat end 38 of which extends close to the transition region 26.
  • This inner bore 34 has an inner diameter D2 which is at least as large, preferably somewhat larger than the outer diameter D1 of the transition region 26.
  • the inner bore 34 merges into an inner edge, in particular into an internal hexagon 36, which at the same time forms the engagement part for attaching a tool in order to screw the contact screw 10 into a clamp.
  • a predetermined breaking point 40 is formed between the front region of the inner bore 34 and its conical end 38 on the one hand and the wall of the annular groove 20 which has remained after the annular groove 20 has been formed, and has the shape of a rotationally symmetrical shearing edge.
  • this predetermined breaking point 40 By suitable dimensioning of the wall thickness of this predetermined breaking point 40, it can be set at which frictional resistance, which acts on the screw-in part 16, the screw-in part 16 tears off at its transition region 26 from the shaft 12.
  • the contact piece 28 is designed as a contact plate, the contact diameter D3 of which is substantially larger than the outer diameter D4 of the shaft 12 or of the cylinder part 32.
  • this frictional resistance can be set by the number of milling slots 42 which are formed in the screw-in part 16, it also being possible, of course, to provide more than three milling slots 42 according to FIG. 3.
  • the inner edge in particular the inner hexagon 36, can be used for this purpose. If necessary or desired, another engagement part on the contact screw 10 can also be used, for example an external hexagon not shown in the drawings.
  • the conductor insulation is first milled through by the milling slots 42 in the screw-in part 16, then the conductor surface of the electrical line to be contacted is milled until it is flat.
  • This can be a particularly soft conductor material or the conductor surface of a multi-wire conductor.
  • the arrangement of the contact screw 10 according to the invention is advantageously made such that on the one hand the two end faces 22 and 24 of the annular groove 20 and on the other hand the contact surface 30 of the screw-in part 16 run essentially plane-parallel to one another, because this enables a particularly uniform contact pressure to be generated.
  • a lubricant for example in pasty form, into the space of the annular groove 20. This ensures that sufficient lubrication takes place between the two surfaces 22 and 24 when the contact screw 10 is tightened during operation, so that a driver effect is excluded.
  • the cylinder part 32 and the cylindrical shaft 12 are in frictional engagement over the full surface of the opposing surfaces 22 and 24, so that good mechanical and electrical contact is ensured by the contact screw 10.
  • FIG 4 shows in longitudinal section a side view of a further embodiment of the contact screw 10 according to the invention, only the rear region of the contact screw 10 is shown.
  • the front area is designed in the manner as explained above in connection with FIGS. 1 to 3, the diameter of the contact piece 28 being able to be selected according to the respective requirements.
  • the contact screw 10 has a weakening zone in the rear region of the cylindrical shaft 12, which is designed, for example, as a circumferential shear groove 52 and can have, for example, a V-shaped cross section with a suitable opening angle A.
  • the shearing groove 52 delimits a tear-off head 50 in the axial direction from the rear edge 56 in the direction of the contact piece 28, which tear-off head 50 only breaks off when a predetermined torque is exceeded when the contact screw 10 is tightened.
  • This limit torque is of course greater than the torque that leads to the breaking of the predetermined breaking point 20.
  • At least one projection 48 is provided in the area of the shear-off head 50 in the vicinity of the shear-off groove 52 towards the rear edge 56, which protrudes into the interior of the inner edge 36.
  • Such projections 48 limit the insertion of a tool in a position slightly above the shear groove 52 in the axial direction, so that the shear groove 52 serves as a torque limitation for the effective body of the contact screw 10.
  • radially extending recesses 44 are provided for this purpose in the cylindrical shaft 12, which have a depression 46 in their radially inner regions, which can be produced in a simple manner with a punching tool or a punch .
  • The, for example, cylindrical recesses 44 can serve as a guide when attaching the respective tool.
  • the blunt front end of the depression 46 becomes radial deformed inside so that the nose-shaped radial projections 48 result.
  • two such recesses 44 with corresponding radial projections 48 can expediently be provided according to FIG. 5, the relative position of these recesses 44 then being indefinite and freely selectable with respect to the inner edge 36. 5, the two recesses 44 have an angle of 90 ° between one another, while the inner edge 36 is formed by an internal hexagon with an inner angle of 120 °.
  • the maximum wall thickness between the recess 44 and the hexagon socket 36 is denoted by B, wherein the value is suitably chosen from B, so that the projections 48 Pressing with a reasonable expenditure of force or can take, without undesired deformations of the contact screw 10 itself occur.
  • the lower edge of the hexagon socket 36 is indicated by the reference number 54. It can be seen that after the tear-off head 50 has been sheared off at the level of the shear-off groove 52, a sufficiently large area remains in the shaft 12 into which a tool can be reinserted if, for any reason, the contact screw 10 is actuated at a later time, for example to remove the contact screw 10, is required. 4 that the shear groove 52 in advantageously forms the rear end of the external thread 14, which simplifies the manufacture of the arrangement.
  • the projections 48 can also be formed by a pin which extends transversely through the wall of the tear-off head 50 and which extends at least partially radially into the interior of the hexagon socket 36. Such a pin is naturally also removed together with the tear-off head 50 if it shears off when the predetermined torque is exceeded.

Landscapes

  • Connections By Means Of Piercing Elements, Nuts, Or Screws (AREA)
EP92108684A 1991-05-23 1992-05-22 Vis de contact Expired - Lifetime EP0514924B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4116876A DE4116876A1 (de) 1991-05-23 1991-05-23 Kontaktschraube
DE4116876 1991-05-23

Publications (2)

Publication Number Publication Date
EP0514924A1 true EP0514924A1 (fr) 1992-11-25
EP0514924B1 EP0514924B1 (fr) 1995-09-06

Family

ID=6432276

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92108684A Expired - Lifetime EP0514924B1 (fr) 1991-05-23 1992-05-22 Vis de contact

Country Status (2)

Country Link
EP (1) EP0514924B1 (fr)
DE (2) DE4116876A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0599346A3 (fr) * 1992-11-27 1995-04-05 Arcus Elektrotech Borne de branchement à phase multiple.
EP0692643B2 (fr) † 1994-07-15 2005-03-30 ARCUS ELEKROTECHNIK Alois Schiffmann GmbH Vis frangible

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006048177A1 (de) * 2006-10-10 2008-04-24 Pfisterer Kontaktsysteme Gmbh & Co. Kg Befestigungsmittel, insbesondere Abreißschraube, mit abtrennbarem Klemmabschnitt
ES2343086T3 (es) * 2007-01-26 2010-07-22 Arcus Elektrotechnik Alois Schiffmann Gmbh Tornillo de cizalla y procedimiento para su fabricacion.

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE639459C (de) * 1934-10-04 1936-12-05 Aeg Unverlierbares Druckstueck an Schrauben, insbesondere zum Festklemmen von elektrischen Leitungsdraehten
US3487354A (en) * 1968-01-26 1969-12-30 Alfred D Duncan Connector for insulation covered conductors
CH541874A (it) * 1970-09-23 1973-09-15 Bassani Spa Morsetto per la connessione di conduttori ad apparecchiature elettriche
GB1424464A (en) * 1972-10-19 1976-02-11 Geschwister Petri Handelsgesel Contact screw with cutting slot for electrical branch terminals
FR2378969A1 (fr) * 1977-01-26 1978-08-25 Caillau Ets Collier de serrage
EP0420060A1 (fr) * 1989-09-28 1991-04-03 ARCUS ELEKROTECHNIK Alois Schiffmann GmbH Vis de contact

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE639459C (de) * 1934-10-04 1936-12-05 Aeg Unverlierbares Druckstueck an Schrauben, insbesondere zum Festklemmen von elektrischen Leitungsdraehten
US3487354A (en) * 1968-01-26 1969-12-30 Alfred D Duncan Connector for insulation covered conductors
CH541874A (it) * 1970-09-23 1973-09-15 Bassani Spa Morsetto per la connessione di conduttori ad apparecchiature elettriche
GB1424464A (en) * 1972-10-19 1976-02-11 Geschwister Petri Handelsgesel Contact screw with cutting slot for electrical branch terminals
FR2378969A1 (fr) * 1977-01-26 1978-08-25 Caillau Ets Collier de serrage
EP0420060A1 (fr) * 1989-09-28 1991-04-03 ARCUS ELEKROTECHNIK Alois Schiffmann GmbH Vis de contact

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0599346A3 (fr) * 1992-11-27 1995-04-05 Arcus Elektrotech Borne de branchement à phase multiple.
EP0692643B2 (fr) † 1994-07-15 2005-03-30 ARCUS ELEKROTECHNIK Alois Schiffmann GmbH Vis frangible

Also Published As

Publication number Publication date
EP0514924B1 (fr) 1995-09-06
DE59203526D1 (de) 1995-10-12
DE4116876A1 (de) 1992-11-26

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