Patent Publication Number: US-2012023740-A1

Title: Applicator device for attaching metal terminals onto electrical cables by controlled crimping onto the conductor of said cables and crimping unit equipped with this device

Description:
The present invention concerns an applicator device for attaching metal terminals onto electrical cables, equipped with systems for controlled crimping of the terminal onto the conductor part of these cables. The invention also extends to the crimping unit equipped with this device. 
     The field of the invention is that of devices used for attaching metal terminals onto electrical cables. An example of these applicator devices is provided by Italian patent application no. TO2001A000022, filed in the name of the same Applicant. 
     With the object of ensuring that the pressure exerted on the crimping zone of the terminal onto the cable is as per design, the practice is known of providing load cell systems which sense the action of the press on the assembly of the knives (for crimping respectively the insulation and the conductor of the electrical cable) and of the blade for cutting and detaching the terminal from the respective carrier strip. 
     This type of known solution however has the disadvantage of not allowing the possibility of selecting monitoring of the specific action performed by the press on the conductor part of the electrical cable, which is the critical part for the functionality of the connection and the overall quality of the crimping. In consequence it is possible that, for a given total pressure exerted by the press on the terminal, the specific action on the conductor part of the electrical cable will be insufficient to obtain the correct state of crimping. Consequently the product obtained could undergo incorrect crimping which, in the most serious cases, could even mean that the connection at the point of contact between the cable and the terminal fails to achieve electrical conductivity. 
     The principal object of the present invention consists in providing an applicator device which enables the desired action of the press on the conductor part of the electrical cable to be guaranteed, so as to ensure the achievement of the perfect state of crimping onto the latter. 
     These and other objects are achieved with the device and the crimping unit of respectively claims  1  and  7 . Some preferred ways of embodying the invention are contained in the remaining claims. 
     In relation to the known devices, the device realised according to the present invention offers the advantage of selectively detecting the action of the press on the knife which acts on the conductor part of the electrical cable. In this way it is guaranteed that this is actually the action desired, thus isolating it from being influenced by the effect of the press itself on the remaining movable or active parts of the device (in particular the knife for the insulation and the blade for detaching the terminal from the strip). 
    
    
     
       These and other objects, advantages and characteristics are apparent from the description which follows of a preferred embodiment of the device and the crimping unit of the present invention, illustrated by way of non-limiting example in the attached drawings, where: 
         FIG. 1  illustrates in perspective a crimping press equipped with the device of the invention, represented in section along the longitudinal axis; 
         FIG. 2  illustrates in a side view the press shown in  FIG. 1 ; 
         FIG. 3  illustrates a section view of the enlarged detail of the device fitted to the press shown in  FIG. 2 . 
     
    
    
     In  FIG. 1 , reference no.  1  indicates the unit (in the example illustrated, a press) for crimping metal terminals onto electrical cables, while reference no.  2  distinguishes the applicator device of the invention. 
     The press  1  is in particular equipped with an eccentric shaft  3 , suitable for exerting a thrust F 1  on the crimping assembly  4  of the device  2 , said assembly comprising the knife  5  for crimping the conductor part of the cable, the knife  6  for crimping the insulation part, and the blade  7  for detaching the terminal from the respective carrier strip. 
     As is better illustrated in  FIG. 3 , the crimping device  2  is equipped with a load cell  10  which receives the reaction F 3  to the force F 1  exerted by the press  1  on the knife  5  which acts on the conductor part of the electrical cable, respectively through a counterthrust shaft  9  and a block  8 . In particular this reaction F 3  is transmitted, by shaft  9  to block  8 , through the common support surface  14  and, by block  8  to knife  5 , by means of the common support surface  13 . 
     For its part, the remaining part of the support  11  for the crimping assembly  4  acts respectively on the knife  6  for the insulation and on the above-mentioned blade  7 , the latter receiving the movement of the slide  12  activated by the eccentric shaft  3 . This support  11  bears in its turn on the same slide  12 , in the area of contact surfaces  15  laterally located with respect to the above-mentioned contact surface  14  of block  8  with shaft  9  of the press. 
     To explain it another way:
         the reaction F 3  to the thrust force F 1  exerted by the press  1  on knife  5  is discharged onto load cell  10  by means of block  8  and shaft  9 , through the respective contact surfaces  13  and  14 ;   the reaction F 2  to the same force F 1  on knife  6  and blade  7 , on the other hand, is discharged onto slide  12  by means of crimping support  11 , through contact surfaces  15 A,  15 B.       

     From the description given above, it is clear that there are two parts of crimping device  2  which, independently or selectively, receive reactions F 2  and F 3  to thrust F 1  exerted by press  1 , in particular:
         a first part, formed by support  11  which acts on knife  6  for the insulation and on blade  7  for cutting the terminal; and   a second part, defined by load cell  10 , counterthrust shaft  9 , counterthrust block  8  and knife  5 , which specifically monitors the crimping onto the conductor of the electrical cable.       

     Thanks to this selective distribution of loads, which distinguishes between knife  5  (for crimping onto the conductor of the electrical cable) and knife  6  and blade  7 , it becomes possible to specifically monitor the action of the press on the above-mentioned knife  5 . In this way errors are avoided resulting from reaching a design pressure which however does not distinguish between action on knife  5  for the conductor (critical for the quality of the crimping) and action on the remaining parts of the support  11  for the crimping assembly  4 . 
     Although the invention has been described and illustrated so far with reference to the press shown in  FIG. 1 , it is to be understood that the said invention can equally have application in the case of a mini-applicator, for example as described in Italian patent application no. TO2001A000022, filed in the name of the same Applicant, particularly of the type which comprises a group of adjuster rings for regulating the crimping position of the above-mentioned knives  5  and  6 .