EP1075058A2

EP1075058A2 - Clamping device for clamping metal terminals on electric cables and clamping press including said device

Info

Publication number: EP1075058A2
Application number: EP00113768A
Authority: EP
Inventors: Luigi Aluffo
Original assignee: Mecal Srl
Current assignee: Mecal Srl
Priority date: 1999-08-02
Filing date: 2000-06-29
Publication date: 2001-02-07
Also published as: EP1075058A3; IT1313283B1; ITMI991728A1; ITMI991728A0

Abstract

A device for clamping metal terminals on electric cables comprises an adjustable height bottom (3) provided with a wedge (11) housed and slidable between a top plate (17) for supporting the clamping device (2) and a bottom plate (16).

This device allows to adjust the load of the knives on the metal terminal (9) and on the cable (10) thereby overcoming in a quick and simple manner any clamping defects, without interrupting the operation.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a clamping device for clamping metal terminals on electric cables and a clamping press including the device.
As shown, prior devices for clamping metal terminals on electric cables conventionally comprise an assembly of knives or punches pressing the terminal against an anvil, so as to deform or crimp it to lock it both on the insulation and on the metal core of the electric cable.
In order to adjust the clamping device to the cable size (diameter of the insulation and metal core), an adjusting head is moreover provided, in turn including two ring-nuts allowing to respectively adjust the position of the knife clamping or crimping the metal portion of the cable and that affecting the insulation portion.
From an operating standpoint, at first the knife positions must be set by the mentioned adjusting head, depending on the load to be applied to the cable portions, thereby providing the desired clamping or crimping.
However, frequently, because of wear reasons, cable size differences and/or metal terminal size differences, or for other several reasons, the starting load parameters are altered, thereby the clamping or crimping operation cannot be properly performed.
In such a case, a recovering to starting conditions is at present carried out by operating the adjusting head ring-nuts.
Such an operation, even if it would be justified at the start of the operating cycle, would be however objectable if it would be carried out in a started operating cycle, both because of the complexity associated therewith, and since it requires to inevitably stop the clamping process.

SUMMARY OF THE INVENTION

Accordingly, the main object of the present invention is to provide a novel clamping or crimping device, which, differently from prior art analogous devices, allows to hold optimum clamping conditions during the overall clamping operation, by quick and simple operating steps not requiring any interruptions of the operating cycle.
A further object of the invention is to provide a novel clamping or crimping device allowing to perform in an automatic manner any corrections to the clamping of metal terminals on electric cables, as required because of wear, cable size variations and the like.
According to one aspect of the present invention, the above mentioned objects, as well as yet other objects which will become more apparent hereinafter, are achieved by a clamping device and press according to the independent claims 1 and 11 respectively.
Preferred embodiments of the invention are defined by the remaining claims.
With respect to prior clamping devices, the clamping or crimping device according to the invention allows to adjust the load of the knives on the metal terminal and cable, thereby correcting any clamping or crimping defects, quickly and simply, without interrupting the operation.
In a preferred embodiment of the present invention, the clamping device comprises control means for controlling the above mentioned correcting operations, which can be performed in a fully automatic manner, i.e. without any manual operations.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further features, objects and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred embodiment of the invention which is illustrated, by way of an example, in the figures of the accompanying drawings, where:
Figures 1 and 1a are overall schematic diagrams illustrating a clamping press including the clamping or crimping device according to the invention;
Figure 2 is a side view illustrating the clamping or crimping device mounted on the press shown in Figure 1;
Figures 3 to 6 illustrate the adjustable height bottom mounted on the inventive device, in cross section along the axis of an adjusting screw and according to different height positions;
Figure 7 is an exploded view illustrating the bottom of Figures 3 to 6, together with a top anchoring plate;
Figure 8 is a bottom view illustrating the top plate of the bottom shown in the preceding figures;
Figure 9 illustrates the operating steps of the method for adjusting the clamping by the adjustable height bottom or base of the preceding figures; and
Figure 10 shows a clamped or crimped electric cable, as coupled to a metal terminal.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The reference number 1 shown in Figure 1 indicates the clamping press including, at the bottom thereof, the clamping or crimping device 2 according to the present invention, in turn having an adjustable height bottom or base 3, clearly shown in Figures 3 to 6.
Said device, in particular, is of a type specifically designed to affix the insulation 14 and metal core 15 of an electric cable 10 to a metal terminal 9 as shown in Figure 10.
As clearly shown in Figure 2, the device 2 comprises, at the top thereof, an adjusting head 6, including two controlling ring-nuts 12 and 13 for respectively controlling the knives or punches operating on the insulation portion and metal core of the electric cable 16. Figure 2 shows only one of said knives, being herein indicated by the reference 7.
The counter-biassing element for counter-biassing the above mentioned knives comprise an anvil 8, thereon the terminal 9 and electric cable 10 are abutted.
The anvil 8 is, in turn, supported by the plate 29 of the clamping or crimping device 2.
An anchoring plate 4 for anchoring the plate 29 of the device 2 on the adjustable height bottom 3 being moreover provided.
The quick locking of this base or bottom to the device 2 is performed by a screw 5 (Figure 7).
The adjustable height bottom or base 3 shown in Figures 3 to 7 comprises a wedge element 11, housed and slidable between a bottom plane or plate 16 and a top plane or plate 17.
In particular, the sliding of the wedge element 11 can be carried out by a screw 18 provided for adjusting the height of the bottom 3, said screw being threaded inside the wedge element 11 and being adapted to freely turn in a fixed supporting element 19. In the embodiment being shown, the rotary drive to the screw 18 is derived from an electric motor 20 (Figure 5).
As shown in Figures 3 to 8, the bottom plate 16 of the bottom or base 3 of the clamping device 2 comprises a rectilinear wall metal plate, whereas the top plate or plane 17 is provided with an inner slanted wall 22, thereon a corresponding slanted wall 23 of said wedge element 11 slides (Figure 3).
Locating means 25, comprising preferably pins, pegs and the like, properly locate and guide on the vertical axis the plates 16 and 17 therebetween the wedge element 11 is slidably housed as controlled by said screw 18.
Thus, it should be apparent that, by rotatively operating the screw 18, the wedge element 11 will be caused to slide in the direction of the arrows F1 thereby either raising or lowering the top plate or plane 17 with respect to the bottom plate or plane 16, in the direction of the arrows F2 of Figure 6.
As hereinabove stated, the clamping operation comprises, at the start thereof, an adjusting of the ring-nuts 12 and 13 thereby properly setting the positions of the knives and, accordingly the load provided thereby on the terminal 9 to clamp said terminal 9 to the insulation 14 and metal portion 15 of the electric cable 10.
Then, from this time, coinciding with the position γ_o of the plate 4 supported by the bottom 3, the press 1 is started to operate the device 2 which, by its knives counter-biassed by the mentioned anvil 8 supported by the plate 9, will provide a proper clamping of the terminal 9 to the cable 10.
If, in operation, malfunctions of the clamping would occur (usually an anomalous deformation of the terminal on the desired portions of the electric cable, is due, for example, to a wear of the knives or of the anvil or, frequently because of size variations of the electric cable, metal terminal or both, even considering possible variations of the physical characteristics of the materials used for making the terminals and electric cables), then a recovery to the set pressure values would be obtained by changing the height of the bottom or base 3 within the values γ_o - α and γ_o + α, by properly holding at γ_o the bottom limit position of the knives of the clamping device 2 (Figure 9).
Thus, for example, if an increase + α of the height of the terminal 9 from the set starting value occurs, then the height of the bottom or base 3 will be proportionately reduced to the amount γ_o - α.
Vice versa, if a decrease - α of the terminal 9 height occurs, then the height of the bottom or base 3 will be proportionately increased up to a value γ_o + α.
Such a correction, performed by also manually operating on the screw 18, can be carried out during the clamping or crimping operation itself, without interrupting it.
Advantageously, the clamping or crimping device according to the invention is provided with means, generally indicated by the reference number 26 in Figure 9, for reading the position of the plate 4, thereby facilitating and making more accurate the correction of the bottom or base 3 height.
The above mentioned means can comprise, for example, suitable sensing means.
According to a preferred embodiment of the invention, a sensing element adapted to detect or sense the clamping load (for example a load cell 27) can be added to the system, at a position suitable for sensing or detecting the clamping or crimping load.
By way of an example, such a sensing element could be located, indifferently, either under the plate 29 supporting the clamping device 2 (Figure 2) or on the knif pushing axis or, simultaneously, in both the mentioned positions (which variations have not been shown).
Said sensing or detecting element, in turn, would be suitably interfaced with a controlling unit 28 for controlling the height of the bottom or base 3.
Thus, if the clamping load would deviate from a set value, as detected by the sensing element 27, then the control unit 28 would modify in a corresponding manner the height of the base or bottom 3 to recover the starting load value.
The invention, as disclosed, is susceptible to several modifications and variations all of which will come within the scope of the accompanying claims.
Thus, for example, instead of the screw 18 for driving the wedge element 11, it is moreover possible to provide an oleodynamic, pneumo-hydraulic piston, a cam system, a pinion-rack assembly and the like.

Claims

A clamping device for clamping metal terminals on electric cables, of the type comprising a plurality of knives operating, against an anvil, on an insulation portion and a metal portion of a said cable, as well as an adjusting head including controlling ring-nuts for controlling the displacement of said knives, and being characterized in that said device comprises adjustable height means for supporting said anvil (8).
A device according to Claim 1, characterized in that said adjustable height means comprise an adjustable height bottom (3).
A device according to Claim 2, characterized in that said adjustable height bottom (3) comprises a wedge element (11) housed and slidable between a top supporting plate (17) supporting said anvil (8) and a bottom plate (16).
A device according to Claim 3, characterized in that said top plate (17) is provided with a slanted inner wall (22) for sliding thereon a corresponding wall (23) of said wedge (11).
A device according to Claims 3 or 4, characterized in that said device comprises moreover an adjusting device for adjusting the operating stroke of said wedge element (11) in said bottom (3).
A device according to Claim 5, characterized in that said adjusting device comprises a driving screw (18) and that said bottom (3) comprises a fixed supporting element (19) for said adjusting driving screw, an end portion whereof is threaded to said wedge element (11).
A device according to one or more of the preceding claims, characterized in that said device comprises moreover locating and guide means for properly locating and guiding said plates (16, 17), as well as a top plate (4) coupled to said top plate (17) for anchoring said bottom (3) to said clamping device (2).
A device according to one or more of the preceding claims, characterized in that said device comprises moreover reading devices (26) for reading the height of said bottom (3).
A device according to one or more of the preceding claims, characterized in that said device comprises at least a sensing element for sensing the clamping load of said knives on said metal terminal, and a driving motor (20) for driving said screw (18) and control unit (28) for said motor, the operation of said motor depending on the load data sensed by said sensing element and controlled by said control and driving unit.
A device according to the preceding claims, characterized in that said at least a sensing element comprises a load cell (27) arranged at said bearing section of said device (2) on said bottom (3), on the pushing axis of said knives, or simultaneously at both said positions.
A press for clamping metal terminals on electric cables, characterized in that said press comprises a device according to one or more of the preceding claims.