Abstract:
This invention relates to a linear path slide ( 10 ) with a slide ( 26 ) which is arranged slidingly movable in a housing ( 12 ) along a sliding guide ( 20 ) and safe against torsion and with a hydraulic driving gear ( 40 ) integrated into the slide ( 26 ) for a shifting movement of the slide ( 26 ), whereby a working piston of the hydraulic driving gear ( 40 ) is configured with at least two stages, whereby each stage of the working piston forms a partial hydraulic driving gear ( 40′, 40 ″) of the hydraulic driving gear ( 40 ) so that higher actuation forces can thus be realized.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a linear path slide with a slide which is arranged slidingly movable in a housing along a sliding guide and safe against torsion and with a hydraulic driving gear integrated into the slide for a shifting movement of the slide. 
     Linear path slides of the type according to the kind are known. They are used in particular as actuators in different devices for the processing and machining of metallic materials and plastic or plastic composite materials. The functions of these structural components typically include the pressing, forming, stamping, bending, beading, punching, cutting, jointing, jointing pressing as well as the carrying out of feeding functions with special requirements. Particular requirements are made to the properties of linear path slides among which, in particular, a very high energy density, a very high guiding exactitude as well as a very high stiffness against transverse loads and torsion are to be found. Furthermore, linear path slides should be constructed as compact as possible and allow, as standardized basic structural components, a flexible universal range of application. Moreover, properties such as maintenance-freedom during the whole lifetime, a robust construction for the use in polluted environment, the possibility of any fitting position, absolute tightness (for example by overhead mounting) and not least a low-cost production are desirable. 
     Different configurations of linear path slides are known. Because of the required high energy density, they are preferably hydraulic devices. However, basically the design as a pneumatically driven device is also possible. 
     From the EP 1 050 685 A2, we know a linear path slide in which a hydraulic driving gear is integrated into the slide for obtaining a compact construction and a reduced volume and thus a reduced weight. 
     SUMMARY OF THE INVENTION 
     The aim of this invention is to create a linear path slide of the type according to the kind which can realize high actuation forces by maintaining a compact construction. 
     According to the invention, this aim is achieved by a linear path slide with the characteristics indicated in claim 1. By the fact that a working piston of the hydraulic driving gear is configured at least with two stages, whereby each stage of the working piston forms a partial hydraulic driving gear of the hydraulic driving gear, it is advantageously reached that an increase of the actuation force of the linear path slide is obtained according to the selected multiple-stage design. The actuation forces applied by the individual partial stages are superimposed and thus result in a higher total actuating force. 
     Thus, due to such linear path slides, high processing forces are applied by maintaining an exact guiding and a high stiffness against transverse loads, for example for cutting tools. 
     In a preferred embodiment of the invention, it is provided for that the working piston comprises a guiding element guided slidingly along the housing, guiding element which coaxially encompasses a piston rod fixed with respect to the housing, whereby the guiding element constitutes two inner spaces axially spaced to the piston rod and sealed against each other. Due to such a configuration, it is advantageously reached to use the size available for constituting the partial hydraulic driving gears. In particular, there results then a parallel efficacy of the partial hydraulic driving gears so that the increase of the actuation force of the linear path slide can be obtained in a simple way. 
     According to a further preferred embodiment, two hydraulic working spaces sealed against each other are respectively configured in each of the inner spaces of the guiding element sealed against each other, whereby these working spaces can be optionally charged with hydraulic oil under pressure. Thus, it is advantageously reached that either the adjusting movement of the linear path slide, or the reset movement of the linear path slide can be hydraulically activated. 
     Further preferred embodiments of the invention result from the other characteristics indicated in the subclaims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in detail below with an embodiment with reference to the corresponding drawing which shows in FIG. 1 a longitudinal section through a linear path slide. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a longitudinal path slide designated as a whole as  10 . The longitudinal path slide  10  comprises a housing  12  which constitutes an inner space  14 . The inner space  14  is configured symetrically to a longitudinal axis  16 . An inner wall  18  of the inner space  14  is provided with a slideway  20  which is preferably produced by a casting method in a known way. 
     When we consider the housing  12  in cross section, it is formed for example cylindrically, in particular however as a right parallelepiped. Correspondingly, the inner space  14 , considered in cross section, has a round or preferably a rectangular cross-sectional area. An outer face  22  of the housing  12  preferably forms a mounting surface and possesses a groove  24  for receiving a feather key or the like which serves for positioning and for absorbing the shifting forces. 
     A slide  26  which is guided completely free from backlash in the slideway is placed inside the housing  12 , thus in the inner space  14 . Considered in cross section, the slide  26  possesses a contour which is adapted to the inner space  14 , is thus preferably configured as a right parallelepiped. The slide  26  forms a prismatic slide. The slide  26  possesses a section  28 , protruding lengthwise over the housing  12 , which constitutes an actuation surface  30 . The actuation surface  30  serves for example for receiving tools which are not represented in detail, for example cutting tools or the like, or as a pressure or as a pressing surface which is brought into a bearing contact with a subject to be machined. 
     The forces which the slide  26  must apply in axial direction and resulting transverse forces are within the range of 10 KN to 150 KN, in individual cases also up to 250 KN. Because of an off-center load of the slide  26  during the working process, in particular for cutting tools placed on the slide  26 , transverse forces which act onto the slide  26  can be a multiple of the nominal longitudinal force. 
     The housing  12  is closed at its end opposite the section  28  of the slide  26  by a sealing flange  32 . The sealing flange  32  is connected with the housing  12  by intercalating an intermediate plate  34  over connecting means  36 . Thus, the inner space  14  becomes a blind opening so that a motion stopper is constituted for the slide  26  by the sealing flange  32  or the intermediate plate  34 . 
     The slide  26  forms for its own part a blind opening  38  which is open in direction of the intermediate plate  34 . The blind opening  38  serves for receiving a hydraulic driving gear designated as a whole as  40 . The hydraulic driving gear  40  is thus integrated into the slide  26 . 
     The blind opening  38  of the slide  26  forms the cylinder of the hydraulic driving gear which receives a working piston. The working piston comprises a piston rod  42  which engages with an ring shoulder  44  into a ring groove  46  constituted correspondingly by the sealing flange  32  and the intermediate plate  34 . The piston rod  42  is thus positioned aligned with the longitudinal axis  16 . The piston rod  42  is thus placed fixed, i.e. not movable lengthwise. 
     The piston rod  42  is coaxially encompassed by a guiding element  48  which constitutes a first section  50  forming a cylinder tube  50 ′ and a second section  52 . The sections  50  and  52  have a circumferential backlash of approximately 0.5 mm to the inner wall  54  of the blind opening  38  of the slide  26 . A guiding without any backlash is also possible. It comes to the formation of an ring space  56  between the guiding element  48  and the piston rod  42 . 
     The section  50  of the guiding element  48  is closed pressure sealed by a plug  58  at its front side turned to the section  28  of the slide  26 . The plug  58  is screwed into the cylinder tube  50 ′, i.e. it is screwed by means of an external thread  60  into an internal thread of the cylinder tube  50 ′. A gasket  62  which is outlined here is additionally provided. 
     The sections  50  and  52  of the guiding element  48  are non-positively connected with each other, for example over a thread connection  64 . For this purpose, the sections  50  and  52  are provided with respective corresponding recesses at their ends which are turned to each other. 
     The piston rod  42  possesses a first section  66  with a smaller diameter and a second section  68  with a bigger diameter. A transition piece  70  is placed on the section  66 , this transition piece being placed tightly to the piston rod  42  with a gasket  72  and to the guiding element  48  with gaskets  84 . Thus, there comes to the constitution of a first inner space  74  and of a second inner space  76  of the ring space  56 . The transition piece  70  thus forms a bulkhead wall between the inner spaces  74  and  76 . The transition piece  70  engages with a ring shoulder  78  into a corresponding ring recess  80  between the sections  50  and  52  of the guiding element  48 . Thus, the guiding element  48  and the transition piece  70  are placed in such a way that they are not movable in relation to each other. 
     The piston rod  42  carries a first piston  82  fixedly placed thereon which is placed opposite the plug  58 . The piston  82  is guided by gaskets  84  on the section  50  of the guiding element  48  so that it comes to the constitution of a hydraulic working space  86  between the piston  82  and the plug  58 . 
     Due to the arrangement of the piston  82  and of the transition piece  70 , the inner space  74  also simultaneously forms a hydraulic working space  75 . 
     The piston rod  42  carries a second piston  88  which is also fixedly placed on the piston rod  42 . The piston  88  is guided by means of gaskets  90  on the section  52  of the guiding element  48 . Thus, there comes to the constitution of a hydraulic working space  92  between the piston  88  and the transition piece  70 . 
     Furthermore, the piston rod  42  is encompassed by a screwed connection  94  which is tightly placed on the piston rod  42  by means of gaskets  96 . The screwed connection  94  simultaneously forms a front side seal for the guiding element  48  and the slide  26 . Due to the arrangement of the screwed connection  94 , the inner space  76  simultaneously also forms a hydraulic working space  77 . 
     The piston rod  42  possesses a first axial bore hole  100  and a second axial bore hole  102 . The axial bore hole  100  runs on the one side into the hydraulic working space  86  and over a radial bore hole  104  into the hydraulic working space  92 . The axial bore hole  102  runs over a radial bore hole  106  into the hydraulic working space  74  and over a radial bore hole  108  into the hydraulic working space  76 . The axial bore holes  100  or  102  are respectively connected with a hydraulic oil connecting flange  110  or  112 . The connecting flanges  110  or  112  are connected with not represented hydraulic oil sources. 
     The linear path slide  10  represented in FIG. 1 shows the following functions. 
     For drawing out the slide  26 , hydraulic oil is set under pressure at the connecting flange  110 . Due to the pressure connection over the axial bore hole  100 , the pressure builds up in the hydraulic working space  86  and over the radial bore hole  104  additionally in the hydraulic working space  92 . Thus, a force of pressure orientated to the left—according to the representation of FIG.  1 —is exerted onto the plug  58  and the transition piece  70 . An actuation force resulting herefrom depends on the pressure head and on the pressure loaded surface. Thus, there results the surface of the plug  58  which is turned to the hydraulic working space  86  as pressure loaded surface and the surface of the transition piece  70  which is turned to the hydraulic working space  92  as pressure loaded surface. These pressure loaded surfaces add up to a whole pressure loaded surface so that, compared with the known linear path slides, a higher actuation force can be applied. However, the surface of the transition piece  70  is not completely integrated into the increase of force but must be reduced by the cross section of the section  66  of the piston rod  42 . 
     The force which is building up is transferred over the plug  58  and the guiding element  48  to the slide  26  so that the slide is submitted to a corresponding axial adjusting movement along the longitudinal axis  16 . The maximal stroke of the slide  26  is predetermined here by the axial distance of the piston  82  to the transition piece  70  or of the piston  88  to the screwed connection  94 . 
     A reset movement of the slide  26  is possible in that hydraulic oil under pressure is applied to the connecting flange  112 . This pressure builds up over the axial bore hole  102  and the radial bore holes  106  and  108  in the hydraulic working spaces  75  and  77 . A restoring force orientated to the right—according to the representation in FIG.  1 —builds up according to the pressure loaded surface of the transition piece  70  which is turned to the hydraulic working space  75  and to the pressure loaded surface of the screwed connection  94  which is turned to the hydraulic working space  77 , whereby this restoring force moves the slide  26  into the housing  12 . The screwed connection  94  constitutes simultaneously with the ring shoulder  44  of the piston rod  42  a reset stopper. 
     It is clear that, due to the arrangement of two pistons  82  or  88  on the piston rod  42 —by intercalating a transition piece  70 —the hydraulic driving gear  40  is configured with two stages so that there results an increase of the pressure loaded surface and thus an increase of the actuation force. The piston  82  constitutes in connection with the hydraulic working space  86  and with the section  50  of the guiding element  48  a first partial hydraulic driving gear  40 ′, while the piston  88  in connection with the transition piece  70  and the guiding element  48  constitutes a second partial hydraulic driving gear  40 ″. 
     With respect to the further advantages of the linear path slide  10 , in particular with respect to its compact construction and to the fundamental advantages of a hydraulic driving gear  40  integrated into the housing  12 , we refer to the EP 1 050 685 A2, the content of which is made herewith to the content of disclosure of this invention. 
     The invention self-evidently is not limited to the represented embodiment. So, multiple stage constructions (with more than two stages) are also conceivable. It comes then either to a reduction of the maximal stroke of the linear path slide, or to a bigger axial extension of the linear path slide. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 List of reference numerals 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                  10 
                 Linear path slide 
               
               
                   
                  12 
                 Housing 
               
               
                   
                  14 
                 Inner space 
               
               
                   
                  16 
                 Longitudinal axis 
               
               
                   
                  18 
                 Inner wall 
               
               
                   
                  20 
                 Slideway 
               
               
                   
                  22 
                 Outer face 
               
               
                   
                  24 
                 Groove 
               
               
                   
                  26 
                 Slide 
               
               
                   
                  28 
                 Section 
               
               
                   
                  30 
                 Actuation surface 
               
               
                   
                  32 
                 Sealing flange 
               
               
                   
                  34 
                 Intermediate plate 
               
               
                   
                  36 
                 Connecting means 
               
               
                   
                  38 
                 Blind opening 
               
               
                   
                  40 
                 Hydraulic driving gear 
               
               
                   
                  40′ 
                 First partial hydraulic driving gear 
               
               
                   
                  40″ 
                 Second partial hydraulic driving gear 
               
               
                   
                  42 
                 Piston rod 
               
               
                   
                  44 
                 Ring shoulder 
               
               
                   
                  46 
                 Ring groove 
               
               
                   
                  48 
                 Guiding element 
               
               
                   
                  50 
                 First section 
               
               
                   
                  52 
                 Second section 
               
               
                   
                  54 
                 Inner wall 
               
               
                   
                  56 
                 Ring space 
               
               
                   
                  58 
                 Plug 
               
               
                   
                  60 
                 External thread 
               
               
                   
                  62 
                 Gasket 
               
               
                   
                  64 
                 Threaded connection 
               
               
                   
                  66 
                 First section 
               
               
                   
                  68 
                 Second section 
               
               
                   
                  70 
                 Transition piece 
               
               
                   
                  72 
                 Gasket 
               
               
                   
                  74 
                 First inner space 
               
               
                   
                  75 
                 Hydraulic working space 
               
               
                   
                  76 
                 Second inner space 
               
               
                   
                  77 
                 Hydraulic working space 
               
               
                   
                  78 
                 Ring shoulder 
               
               
                   
                  80 
                 Ring recess 
               
               
                   
                  82 
                 Piston 
               
               
                   
                  84 
                 Gaskets 
               
               
                   
                  86 
                 Hydraulic working space 
               
               
                   
                  88 
                 Piston 
               
               
                   
                  90 
                 Gaskets 
               
               
                   
                  92 
                 Hydraulic working space 
               
               
                   
                  94 
                 Screwed connection 
               
               
                   
                  96 
                 Gaskets 
               
               
                   
                 100 
                 First axial bore hole 
               
               
                   
                 102 
                 Second axial bore hole 
               
               
                   
                 104 
                 Radial bore hole 
               
               
                   
                 106 
                 Radial bore hole 
               
               
                   
                 108 
                 Radial bore hole 
               
               
                   
                 110 
                 Connecting flange 
               
               
                   
                 112 
                 Connecting flange