Abstract:
In an electrical plug-and-socket device for transferring electrical energy from an external source of current to an electrical load arranged in a body, preferably in a chuck body of a chuck, in particular an electrical drive motor for actuating the clamping jaws of the chuck, consisting of: —a socket possessing at least two accommodation openings, a body and an electrical load arranged therein, each of which is connected to the source of current via an electrical cable and of at least two plugs connected to the load by one electrical cable each, with the plugs arranged in the body and coupled to the particular accommodation openings of the socket during the electrical energy transfer, and in which the plugs can be removed from the accommodation openings following the energy transfer, and automatic plug-and-socket connection should be created.

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATION 
     This patent application claims benefit of European Patent Application No. 15 161 271.0, filed Mar. 27, 2015, which patent application is hereby incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a plug-and-socket device for transferring electrical energy in accordance with the pre-characterising clause of patent claim  1 . 
     BACKGROUND OF THE INVENTION 
     The process of transferring electrical energy from a source of current to an electrical load using a plug-and-socket device is adequately known. However, such an energy transfer is problematic if the connection of the plug-and-socket device must be carried out by automated means, for example on a machine tool or the like, because in such a case it is necessary to ensure that the coupling procedures can be generated by the machine and take place according to a specified control sequence. 
     Furthermore, not only are such plug-and-socket devices used on a machine tool in the area of the loading station, but together with the body at least parts of the plug-and-socket device enter a machining area of the machine tool where chips, contaminated water and other impurities occur, by means of which the parts of the plug-and-socket device arranged in the body become contaminated or suffer partial or irreparable damage with the effect that a correct coupling procedure can no longer be guaranteed for the plug-and-socket device. 
     JP S 62 277237 discloses an electrical plug-and-socket device which transfers electrical energy from an external source of current to a load arranged on a shaft and makes it possible for data to be transferred. As a result of their susceptibility to contamination, plug-and-socket devices of this kind suffer from the aforementioned disadvantages. 
     SUMMARY OF THE INVENTION 
     Therefore, it is the task of the present invention to develop a plug-and-socket device of the aforementioned type in such a way that the coupling procedure between the plugs and the particular opening of the socket provided for this purpose, which are spatially separate from one another, takes place automatically. Moreover, the interfaces, and in particular the transitional areas, should seal the components in the body of the plug-and-socket device with a water and/or air-tight seal to prevent the ingress of contamination or damage. 
     These tasks are carried out in accordance with the present invention by the features of the characterising clause of patent claim  1 . 
     Other advantageous further embodiments of the present invention are derived from the subordinate claims. 
     For the reasons that the socket can be moved in the direction of the body by means of a first advance device, that a holding pocket is worked into or provided in the body into which the first advance device can be inserted with the socket, that the body has a chamber provided in it which opens into the holding pocket, that the chamber has a second advance device mounted in it in a movable arrangement with a free end pointing towards the holding pocket on which the plugs are arranged, and that the advance movement of the second advance devices brings the plugs into active contact with one each of the accommodation openings of the socket for transferring electrical energy and for generating the coupled status, and with the second advance device withdrawing the plugs at the end of the energy transmission and for the purpose of uncoupling from the particular accommodation opening of the socket, the situation is reliably achieved that the coupling of the plugs with the corresponding accommodation openings of the socket can be achieved by automated means within a specified time interval. 
     It is particularly advantageous if the advance movement of the first advance device takes place prior to the advance movement of the second advance device, because this guarantees that the socket will already be positioned in the body, meaning that the plugs can subsequently be placed in the corresponding accommodation openings of the socket. 
     For this purpose, the chamber in which the second advance device is arranged in a movable arrangement should run at right angles to the holding pocket into which the first advance device engages. 
     Furthermore, in a further advantageous embodiment of the present invention, the second advance device can be actuated by means of a third advance device which can be actuated in the housing in which the first advance device is also arranged. The second advance device has a slanted plane which interacts in a driving active contact with a slanted plane provided on the third advance device. When, accordingly, the third advance device is moved in the direction of the second advance device, the alignment of the slanted plane causes the second advance device to be moved in the direction of the holding pocket, and thus the plugs are moved in the direction of the accommodation openings of the socket. The body accommodates a chuck for holding workpieces that are transferred from the loading and unloading station into a machining zone of a machine tool and contamination occurs in the area of the machining zone in the form of chips, contaminated water and other particles, as a result of which it is particularly advantageous if the opening of the holding pocket is provided with a water and/or an air-tight seal as long as the body is arranged in the area of the machining zone of a machine tool. For this purpose, the opening of the holding pocket is sealed by means of a sealing cover which is mounted in an axially moving arrangement on the holding pocket. When the first advance device engages, the sealing cover is pressed in the direction of a base of the holding pocket, meaning that the socket is positioned in the area of the chamber. The sealing cover has a U-shaped cross section and accommodates a coil compression spring in one area that is supported at the opposite end on the base of the holding pocket. 
     As soon as the first advance device has been pulled out of the holding pocket, the coil compression spring presses the sealing cover into the initial position in the area of the opening of the holding pocket with the effect that the sealing cover provides a flush seal with the outside of the body. Furthermore, the sealing cover acts as a stop in the pressed-in condition because it can be regarded as a spacer as a result of its U-shaped cross sectional contour. This is because the sealing cover makes contact with the base of the holding pocket and terminates approximately in the area where the chamber opens out into the holding pocket, meaning that the first advance device enters into contact with the sealing cover as soon as the movement of the first advance device into the holding pocket has stopped, as soon as the socket is positioned opposite the chamber. 
     In order to blow or flush away possible adhesions of chips, particles and other impurities in the area of the opening of the holding pocket and/or in the interface area between the second and third advance devices, blowing openings are provided in the housing in which the first and third advance devices are arranged, which direct a flow of air and/or liquid in the direction of the interfaces between the second and third advance devices and the opening of the holding pocket, or transfer such a flow to these positions, with the effect that the impurities adhering there can be removed. 
     Proximity switches provided on the first and third advance devices also enable the distance from the first and third advance devices to the particular components arranged in the body to be monitored and controlled. This information and the timing sequence in which the first and third advance devices are activated is provided and undertaken by a control unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawing shows two sample embodiments of a plug-and-socket device configured in accordance with the present invention, the details of which are explained below. In the drawing, 
         FIG. 1  shows a first sample embodiment of a plug-and-socket device for transferring electrical energy from a source of current to an electrical load arranged in a chuck, by means of which the clamping jaws of the chuck can be advanced and locked in a loading and unloading station as well as in a machining zone of a machine tool, as a sectional view in each case, 
         FIG. 2  shows a second sample embodiment of a plug-and-socket device for transferring electrical energy from a source of current to an electrical load arranged in a flange, by means of which a clamping device in the form of a vice is driven, as a sectional view, 
         FIG. 3  shows the individual parts of one of the plug-and-socket devices in accordance with  FIG. 1 or 2 , in the removed condition, in particular a first advance device on the free face end of which a socket with accommodation openings is mounted, with a second advance device mounted in a sliding arrangement in a body of the chuck or the flange with at least two plugs facing the accommodation opening of the socket, and with a third advance device by means of which the second advance device can be actuated, 
         FIG. 4 a    shows the plug-and-socket device in accordance with  FIG. 3  in the assembled condition and in the initial position, as a sectional view, 
         FIG. 4 b    shows the plug-and-socket device in accordance with  FIG. 4 a    in the contact condition between a housing accommodating the socket and the body or flange, 
         FIG. 4 c    shows the plug-and-socket device in accordance with  FIG. 4 b   , in which the first advance device with the socket has moved into the body or flange, 
         FIG. 4 d    shows the plug-and-socket device in accordance with  FIG. 4 c    in which both the first and the third advance devices have moved into the body and in which the second advance device has been moved in the direction of the socket in order to generate a coupling condition between the plugs and the accommodation openings of the socket, 
         FIG. 5 a    shows a section through the plug-and-socket device in accordance with  FIG. 4 c    along the section line Va/Va and 
         FIG. 5 b    shows the plug-and-socket device as a sectional view according to  FIG. 4 d    along the section line Vb/Vb. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a plug-and-socket device  1  by means of which an electrical load, for example a drive motor  7 , is to be electrically connected to a source of current  8 . The drive motor  7  in this case is arranged spatially separated from the source of current  8  in a body  6 , for example a chuck body  6  of a chuck  9 . 
     The drive motor  7  should enable the clamping jaws  36  assigned to the chuck  9  and mounted in it in a movable arrangement not only to be advanced but also to be held in their locking position so as to clamp a workpiece  35 . The loading and unloading zone of a machine tool is identified by the reference number  31 . 
     A machine tool indicated schematically in the form of a tool  34  is intended to machine the workpiece  35  clamped in a machining zone  32  by cutting operations. Such machining procedures can be carried out, for example, by turning, milling, drilling or the like. 
     In order to provide electrical power to the drive motor  7 , it must be given adequate electrical energy during the loading and unloading time via the plug-and-socket device  1 . As soon as the workpiece  35  is locked in the chuck  9 , it should be transferred or swivelled to the machining zone  32 . In order to permit movement of the chuck  9  out of the loading and unloading zone  31 , this means the plug-and-socket device  1  must be configured in such a way that the electrical components assigned to the body  6  of the chuck  9  must be able to be spatially separated from the electrical components of the plug-and-socket device  1  that are connected to the source of current  8 . 
     Furthermore, the machining procedures on the workpiece  35  give rise to contamination, for example in the form of chips  36 , contaminated water, hydraulic fluid and the like. Consequently, during the machining procedure, the body  6  and the electrical components installed therein should be encapsulated so they are water and air-tight, with the effect that the contamination  36  cannot reach the electrical components of the plug-and-socket device  1 . 
       FIG. 2  shows that the plug-and-socket device  1  can also be used in a flange  17 . By means of electrical cables  5 , the plug-and-socket device  1  of the flange  17  is connected to the electric drive  7 , by means of which a vice  20  or another clamping device, for example, can be actuated. 
     Both embodiments of  FIGS. 1 and 2  share the design structure explained more specifically below that can be seen in detail in  FIG. 3  in the form of an exploded view. The plug-and-socket device  1  in this case consists of a socket  2  with at least two accommodation openings  3  that serve as socket positions and for electrical coupling. In this case, the particular accommodation openings  3  are electrically connected to the source of current  8  via electrical cables  5 . 
     The socket  2  is attached to a first advance device  11  which is configured as a pneumatically operated piston. The socket  2  is provided on a free face end of the piston  11  that can be advanced in the direction of the body  6  or the flange  17  as shown in  FIG. 1 or 2 . In order to mount the first advance device  11 , it is arranged in a housing  10  which is attached in a locationally fixed and spatially separated arrangement with regard to the body  6 . 
     The body  6  has a chamber  14  worked into or provided in it, in which a second advance device  12  in the form of a pin or rod is mounted in an axially moving arrangement. The chamber  14  opens out into a holding pocket  13  worked into the body  6 . The lengthways axis of the holding pocket  13  and the lengthways axis of the chamber  14  are at right angles to one another. 
     At least two plugs  4  are attached to the free face end of the second advance device  12  facing towards the holding pocket  13 , meaning that the plugs  4  project in the direction of the holding pocket  13 . 
     Furthermore, a third advance device  23  is arranged in an axially moving arrangement in the housing  10  at a spatial distance from the first advance device  11 , and the third advance device  23  is pneumatically operated. It is configured as a piston that can be moved in the direction of the body  6 . 
     The driving active connection between the third and second advance devices  23  and  12  can be achieved, in principle, in two ways. Firstly, the free end of the third advance device  23  can act directly on the free end of the second advance device  12  which points towards a passage opening  18  worked into the body  6 . The contact surface identified as the interface between the two advance devices  12  and  23  is configured as slanted planes  29  and  30  running in parallel and in contact with one another such that when the third advance device  23  is advanced, the second advance device  12  is moved axially in the direction of the holding pocket  13 . 
     In order to close the passage opening  18  with an air and/or water-tight seal, it has a sealing sleeve  37  inserted in it in an axially moving arrangement. The sealing sleeve  37  moreover acts as a transmission element for the advance movement of the third advance device  23  onto the second advance device  12 , and specifically in such a way that an intermediate element of  24  is attached between the sealing sleeve  37  and the free end of the second advance device  12 . Not only the sealing sleeve  37  but also the intermediate element  24  possesses the particular slanted planes  29  and  30  which slide along one another in a previously explained manner as soon as the sealing sleeve  37  is pushed into the body  6  by the third advance device  23 . The advance movement of the sealing sleeve  37  namely moves the intermediate element  24  and thus the second advance device  12  in the direction of the holding pocket  13 . 
     When the third advance device  23  is moved into the body  6  and into the chamber  14 , the two slanted planes  29  and  30  either of the third advance device  23  and the second advance device  12  or of the sealing sleeve  37  come into contact with the intermediate element  29 , and slide along one another in a relative movement. The inclination of the two slanted planes  29  and  30  in this case runs parallel and at an angle to the lengthways axis of the second advance device  12  in such a way that the movement of the third advance device  23  causes the second advance device  12  to be moved or pushed in the direction of the holding pocket  13 . 
     In order to provide the body  6  with an air and water-tight closure or seal, especially during the machining procedure in the machining zone  32 , the holding pocket  13  has a sealing sleeve  37  and intermediate element  24  assigned to it, which are supported by means of a coil compression spring  25 . 
     The coil compression spring  25  of the sealing cover  21  lies on or against a base  28  of the holding pocket  13  and on the inside of the sealing cover  21 . The sealing cover  21  has a U-shaped cross-section, with the effect that an area of the coil compression spring  25  is enclosed by the sealing cover  21 . Furthermore, the outsides of the sealing cover  21  form a cylindrically shaped outer jacket surface that provide a guide on the inside wall of the holding pocket  13  corresponding to the outer contour of the sealing cover  21 . As a result, the sealing cover  21  can be pushed along the inside wall of the holding pocket  13  in a guided manner when the first advance device  11  engages in the holding pocket  13 . 
     In order to establish the active connection between the third and the second advance device  23  or  12 , the passage opening  18  is worked into the body  6  in the area of the third advance device  23 , with the effect that the free face end of the third advance device  23  enters into a direct driving connection by its slanted plane  30  with the slanted plane  29  of the second advance device  12  or the sealing sleeve  37  is pressed into the body  6  by the third advance device  23 , as a result of which the second advance unit  12  can be moved. The second advance device  12  closes the passage hole  18  in the initial condition, meaning that no dirt particles  36  enter the body  6  through the passage hole  18 . At most, such particles  36  can settle on the slanted plane  29  and will be flushed off by compressed air or a flow of liquid before the third advance device  23  is brought into active contact with the second advance device  12  again. The first and the third advance devices  11  and  23  run in parallel and spaced apart from one another within the housing  10  and are operated by means of a control unit  16 . 
     Moreover, one proximity switch  27  each is attached to the first and third advance devices  11  or  23  in order to measure the gap between them and the bodies  6 . The proximity switch  27  is connected to the control unit  16  and generates electrical switching signals by means of which any advance movements of the advance devices  11  and  23  are stopped if the bodies  6  are not correctly aligned in relation to the housing  10 . 
       FIG. 4 a    shows the initial condition of the plug-and-socket device  1 . The body  6  is spatially separated from the housing  10 . The three advance devices  11 ,  12  and  23  are not actuated, with the effect that the first and third advance devices  11  and  23  are completely moved into the housing  10 , the second advance device  12  closes the passage opening  18  and the plugs  4  attached to it are at a distance from the holding pocket  13 . Furthermore, the sealing cover  21  is arranged flush in the opening  19  of the holding pocket  13  so that the holding pocket  13  is sealed thereby with an air or water-tight seal. The sealing cover  21  is positioned so as to be axially movable by means of the coil compression spring  25 . 
       FIG. 4 b    shows the contact condition between the body  6  and the housing  10  of the plug-and-socket device  1 . Accordingly, the body  6  is placed on the locationally fixed housing  10  and the holding pocket  13  runs flush with the first advance device  11 , while the passage opening  18  in the area of the chamber  14  of the body is positioned flush with the third advance device  23 . As a result, the first advance device  11  can move or be moved in the direction of the holding pocket  13  and the third advance device  23  in the direction of the passage opening  18  of the chamber without their movement sequences being obstructed because the sealing cover  21  is pushed by the first advance device  11  in the direction of the base  28  of the holding pocket  13  and the first advance device  11  together with the socket  2  attached to it enters the holding pocket  13  as shown in  FIG. 4 c   . The accommodation openings  3  of the socket  2  can be placed flush with the chamber  14  for holding the plugs  4 . 
     The sealing cover  21  has a U-shaped cross section, as a result of which its circumferential leg enters into active contact with the base  28  of the holding pocket  13  and thus forms a spacer or a stop for the first advance device  11 , with the effect that the movement of the first advance device  11  is limited by the sealing cover  21 . The length of the sealing cover  21  is designed in such a way that the first advance device  11  can indeed enter or move into the holding pocket  13 , although the socket  2  can only be moved as far as the transitional area between the chamber  14  and the holding pocket  13 . As a result, the socket  2  is flush with the chamber  14  for generating a coupling status for the electrical connection between the socket  2  and the plugs  4 . 
       FIG. 4 d    shows the actuation of the second advance device  12  by the third advance device  23 . As soon as the first advance device  11  is positioned in an oriented position in the body  6 , and accordingly the accommodation openings  3  of the socket  2  are pointing in the direction of the plugs  4 , the third advance device  23  is actuated, with the effect that it is moved in the direction of the passage opening  18  of the chamber  14 . Consequently, the slanted planes  29  and  30  of the third and second advance device  23  or  12  come into active contact, which causes the second advance device  12  to be moved in the direction of the accommodation openings  3  of the socket  2 , with the result that the plugs  4  attached to it engage in the accommodation openings  3  and consequently an electrical connection is established between the socket  2  and the plugs  4 . In this position, referred to as the coupling status or the status for the electrical energy transfer, the electrical drive  7  can be supplied with adequate energy or electrical voltage sufficient to carry out the necessary advance movement and locking of a chuck  9  or a pressure cylinder of a vice  20  or of another clamping device or the like. 
     As soon as the workpiece  35  has been released from the body  6  or the flange  17  and an unmachined workpiece  35  has been positioned back on it, the coupling status between the plugs  4  and the accommodation openings  3  of the socket  2  can be disconnected. This is done in reverse order. First, accordingly, the third advance device  23  is moved into the housing  10 . A further coil compression spring  26  assigned to the second advance device  12  and interacting with it removes this and thus also the plugs  4  from the socket  2 . Next, the first advance device  11  can be pulled back into the housing  10 . The coil compression spring  25  subsequently causes the sealing cover  21  to move in the direction of the opening  19  of the holding pocket  13 , with the effect that it is closed before the body  6  is transferred to the machining zone  32 . 
       FIGS. 5 a  and 5 b    show in detail how the second advance device  12  is mounted in the chamber  14  and in what way the slanted plane  29  of the second advance device  12  is inclined in order for this to be able to move axially in the direction of the accommodation opening  13 .