Abstract:
The invention relates to a rotary or pivoting device ( 10 ) comprising a housing ( 12 ), at least one working piston ( 14 ) that is located in the housing and can be impinged by hydraulic fluid and a pivoting part ( 20 ), which is rotatably driven by the working piston via a rotary coupling ( 18 ) and is rotatably mounted in the housing. According to the invention, the working piston is displaceably mounted in at least one cylindrical tube ( 22 ).

Description:
This application is the national stage of PCT/EP2004/003895 filed on Apr. 13, 2004 and also claims Paris Convention priority of DE 103 17 282.3 filed on Apr. 11, 2003. 
   BACKGROUND OF THE INVENTION 
   The invention concerns a rotating or pivoting device having a housing with at least one working piston accommodated in the housing which can be subjected to a pressure medium and with a pivoting member which is mounted to the housing in a rotatable fashion and which can be driven by the working piston via a rotational coupling. The invention also concerns a connection module for a device of this kind. 
   This type of rotation or pivoting device is e.g. disclosed in DE 330648c2. In these pivoting or rotating devices the working piston is borne in a cylinder formed within a housing. Finishing the surface of the cylinder is relatively difficult, although the cylinder surface must have a very precise finish of high quality in order to guarantee a long lifetime for the device. Moreover, access to the surface of the cylinder is difficult and limited due to the pivoting body and its bearing, which render such access difficult. 
   It is therefore the underlying purpose of the present invention to propose a rotating or pivoting device which is practical from a manufacturing point of view while nevertheless permitting high precision for the cylinder in which the working piston is borne in a displaceable fashion. 
   This object of the invention is achieved in a rotating or pivoting device of the above mentioned kind in that the working piston is borne in a displaceable fashion in at least one cylinder tube disposed on a side of the housing. This has the advantage that the cylinder tube can be manufactured as a separate component with highly precise inner dimensions. Cylinder tubes of this kind are easy to handle and process. Very precise inner surfaces on which the working piston abuts can be obtained. This results in a long life time and a very precise pivoting device. 
   In accordance with the invention, at least one cylinder tube can be advantageously screwed into the housing by means of a thread. This facilitates exchangeability of the cylinder tube. Exchange of the cylinder tube increases the lifetime of the pivoting and rotating device without having to process the housing. 
   In an additional embodiment of the invention, the working piston can be subjected to pressure on two pressure sides. Towards this end, the cylinder tube can extend up to at least both pressure sides. The cylinder tube thereby advantageously extends at least along the length of the working piston as well as its piston stroke. The prevision of only one single cylinder tube has the advantage that both pressure sides of the working piston can be guided in one and the same cylinder tube. 
   SUMMARY OF THE INVENTION 
   It is, however, also conceivable that each pressure side of the piston has a separate cylinder tube in which it is borne for displacement. The two cylinder tubes are thereby disposed along a common axis and are preferably identical. This configuration has the advantage that the region between the two pressure sides of the piston is accessible e.g. to fashion a rotational coupling. 
   The rotation coupling is advantageously configured in such a fashion that it comprises a rack-type coupling section on the piston side and a pinion on the pivoting member side which engages in combed fashion with the coupling section. When the working piston is subjected to pressure at both sides, the coupling section is preferentially located between the two pressure sides. Instead of a rack-type coupling section with associated pinion, other types of rotational coupling are also possible in accordance with the invention, e.g. frictional couplings. 
   In a preferred embodiment of the invention, the rotating or pivoting device has at least one connection module for configuration on the free end of the at least one cylinder tube. A connection module can be for example a cover, an extension member, a damping member or some other component which contributes to realization of the particular working behavior of the pivot and rotating device. 
   The free end of the at least one cylinder tube may advantageously be provided with an outer and/or inner thread for screwing on the connection module. In this manner, the connection module can be easily and safely screwed on and off. 
   It is also conceivable for the connection module to be sealed on the radially outer side with respect to the housing in such a fashion that an air chamber is formed which is connected to the corresponding pressure chamber. In this fashion, a reliable air guiding is guaranteed, independent of the depth to which the connection module is screwed in. 
   Towards this end the connection module preferentially has a recess extending in an axial direction in its inner side to connect the air chamber with the pressure chamber. This air-guiding recess can e.g. be configured as a longitudinal groove. The recess preferentially includes radially extending openings on the cylinder tube end sides through which the air can gain entrance from the radially outer side into the radially inner pressure chamber. Sealing means, in particular sealing rings, are provided for sealing. 
   The rotating or pivoting device should also be adapted to accommodate special pivoting tasks. 
   A connection module is provided for extending the pivoting device and can be connected to a cylinder tube accepting the working piston of the rotating or pivoting device. The rotating or pivoting properties of the device can be defined in dependence on the configuration of the connection module. 
   The connection module advantageously has an outer or inner thread for screwing onto the free end of the cylinder tube such that screwing onto the cylinder tube can be effected in a simple manner and without special tools. 
   The connection module can be a cover member for closing the free end of the cylinder tube. It is also conceivable for the connection module to be configured as an abutment member for axially limiting the stroke of the working piston. Towards this end, the abutment member can also function as a cover which closes the free end of the cylinder tube. 
   In accordance with the invention, the connection module may also include damping means for damping the abutment of the working piston. This type of damping means can e.g. be bellows, cushions, or the like provided on the inner side of the connection module facing the working piston. 
   In a particularly preferred embodiment of the invention, the connecting module can be screwed into the cylinder tube at two different depths to change the stroke of the working piston and the associated rotational angle of the pivoting portion in dependence on the depths to which the connection module is screwed in. This has the advantage of being able to adjust the pivoting angle in a simple manner by changing the screw-in depth of the connection module. The connection depths can therefore be used to precisely adjust the rotational angle of the pivoting member. 
   In order to prevent an undesirable change in the operating position of the connection module and thereby to prevent an undesirable change in the rotational angle of the pivoting part, the invention provides means for fixing the connection module and/or on the housing at a certain pre-determined axial position. 
   The connection module can be configured in different ways. It may be made from a single part. However, the connection module may also comprise a sleeve which can be screwed onto the cylinder tube and a locking member which can be screwed into the sleeve. Towards this end, the sleeve can be adjusted in the axial direction relative to the cylinder tube and/or the locking member can be adjusted in an axial direction relative to the sleeve. 
   In another preferred embodiment, the connection module has an abutment member which can be adjusted into at least two positions: an axial inner and an axial outer position, wherein the abutment member can be locked in at least its inner position. An intermediate position is thereby achieved at the axially inner locked position. In the event that the working piston moves against the abutment member in this intermediate position a pivoting of the pivoting member only occurs in this intermediate position. After the locking is released, the working piston moves into its initial position and the pivoting member can also pivot into its initial position. 
   The connection module advantageously has means for screwing the connection module on and off. Such means can have e.g. a hexagonal socket, a hexagonal head, wings for manual operation or the like. A simple and rapid adjustment, removal or screwing on or off of the connection module is thereby achieved. 
   Further advantageous details and embodiments of the invention can be extracted from the following description which describes and explains the invention in more detail with reference to the embodiments shown in the drawing. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  shows a longitudinal section through a first embodiment of a pivoting device; 
       FIG. 2  shows a longitudinal section through a second embodiment of a pivoting device; 
       FIG. 3  shows a front view of the pivoting device in accordance with  FIG. 1  or  FIG. 2 ; and 
       FIG. 4  shows a partial longitudinal section through a third embodiment of a pivoting device. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The pivoting device  10  shown in  FIG. 1  comprises a housing  12  which accommodates two working pistons  14 ,  16  which can be displaced in a longitudinal direction. The working pistons  14 ,  16  are rotatably coupled to a pivoting part  20  via a rotating coupling mechanism  18 . The two working pistons  14 ,  16  are disposed in cylinder tubes  22 ,  24 ,  26 ,  28  at the sides of the housing in such a manner that they can be displaced in a longitudinal direction along their longitudinal axis in the direction of the double arrows  30 . The two working pistons  14 ,  16  of the embodiment shown are each designed to be pressurized from two sides. Towards this end, pressure chambers  32 ,  34  and  36 ,  38  are provided. The pressure chambers can be connected to pressure storages or pressure outlets via feed and discharge lines (not shown). 
   On the sides facing each other, the working pistons  14 ,  16  comprise a coupling section  48  and  50  designed like a piston rod and disposed between their respective pressure sides  40 ,  42 ,  44 ,  46 . The two sections  48 ,  50  mate with a pinion  52  on the pivoting part side which is disposed to be rotatable about the pivot axis  54  of the pivoting part  20  or the pinion  52 . In this view, the rotating coupling mechanism  18  of this design causes pivoting of the pivoting part  20  in a counter clockwise direction upon loading of the pressure chambers  32  and/or  38 . The pivoting part  20  is pivoted in the clockwise direction upon pressurization of the pressure chambers  34  and/or  36 . 
   The cylinder tubes  22 ,  24 ,  26 ,  28  are designed such that the surfaces of the working pistons are reliably guided in the cylinder tubes during maximum strokes of the working pistons  16 ,  18 . The working pistons  14 ,  16  have corresponding sealing elements  56  in the region of their pressure sides  40 ,  42 ,  44 ,  46 . Instead of providing four separate cylinder tubes  22 ,  24 ,  26 ,  28 , each working piston  14 ,  16  may be disposed in one continuous cylinder tube in an axially displaceable manner. However, openings must be provided in the cylinder tubes in the region of the pinion  52  to permit rotating coupling of the pinion  52  with the corresponding coupling sections  48 ,  50 . It is clear that different rotating coupling mechanisms may be provided instead of the illustrated toothed rack/pinion rotating coupling mechanism, e.g. a non-positive, frictional coupling. 
   The individual cylinder tubes  22 ,  24 ,  26 ,  28  have outer threads  58  on their sides facing the housing for screwing into the housing  12 . For exact axial arrangement of the cylinder tubes, the housing  12  comprises abutment edges  60  against which the respective end faces of the cylinder tubes  22 ,  24 ,  26 ,  28  abut in their finally mounted position. Cylinder tubes can be replaced if required by providing threads  58 . Since the cylinder tubes are subjected to wear during operation of the pivoting device  10 , only the faulty cylinder tube needs to be replaced in the inventive pivoting device. The other components of the pivoting device, in particular the housing  12 , can be reused. 
   Two connection modules  62 ,  64  are provided on each free outer end face of the cylinder tubes. The connection modules  62  are cover parts for closing the cylinder tubes  22 ,  28  and can be screwed onto the free end faces of the cylinder tubes  22 ,  28 . Towards this end, the cover parts  62  have an inner thread and the cylinder tubes  22 ,  28  have an outer thread  66 . 
   The connection modules  64  are each formed from two parts and have a sleeve  72  and a closing part  74  which is screwed to the sleeve  72 . The connection module  64  may also be a component formed from one part. The inner side of the closing part  74  serves as an abutment for the pressure sides  42  or  46  of the working pistons  14  or  16 . To damp the impact, the respective working pistons  14 ,  16  comprise damping means  76  which comprise an abutment rod  78  which is disposed for damped displacement in the axial direction relative to the respective working piston  14 ,  16 . The free end  80  of the respective abutment rod  78  consequently abuts the inside of the closing part  74  and damps the working piston  14 ,  16  which moves in the direction of the respective closing part  74 . 
   The connection modules  64  can be screwed, at different depths, into outer threads  66  provided on the respective cylinder tubes  24 ,  28  via corresponding threads, wherein the stroke of the respective working piston  14 ,  16  and therefore the angle of rotation of the pivoting part  20  can be changed via the screwing-in depth of the connection modules  64 . 
   On their respectively radial outer side, the connection modules  62 ,  64  or the sleeves  72  and the cover parts  64  have a circumferential groove with a sealing ring  68 . The sealing rings  68  have a sealing effect on radially inner cylinder surfaces  82  of the housing  12  which extend in an axial direction. The cylinder surfaces  82  and the sleeves  72  or the cover parts  62  define air guiding chambers  84  which can be connected to pressure lines (not shown) via connections  86 . The respective inner side of the connection modules  62 ,  64 , which extends in an axial direction, has at least one recess  88  for guiding air to the respective pressure chambers  32 ,  34 ,  36 ,  38 , the recess(es) extending to the respective cylinder tube end face facing the connection module  62 ,  64 . The recesses  88  may be formed, in particular, as axial grooves. The recesses  88  may comprise additional recesses which extend in a radial direction on the cylinder tube end faces. 
   To pressurize or pressure-relieve the pressure chambers  32 ,  34 ,  36 ,  38 , air can consequently flow in the direction of arrow L from the connections  86  into the respective pressure chamber  32 ,  34 ,  36 ,  38  via the air guiding chambers  84  and respective recess  88 . Reliable air guidance is ensured in the described arrangement irrespective of the screwing-in depth of the respective connection module  62 ,  64 . Moreover, the position of the connections  86  on the housing side is the same for different screwing-in depths. 
   The pivoting device  90  shown in  FIG. 2  substantially corresponds to the pivoting device  10  of  FIG. 1 . Corresponding components have corresponding reference numerals. In contrast to the pivoting device  10  of  FIG. 1 , which merely permits relatively small axial adjustment of the connection modules  64 , the pivoting device  90  of  FIG. 2  has connection modules  92  with sleeves  72  extending relatively far in the axial direction, which permits variation of the pivot angle of the pivoting part  20  within a larger region. In particular, the connection modules  92  can limit the stroke of the working pistons  14 ,  16  to a larger degree than the connection modules  64  of the pivoting device  10  of  FIG. 1  due to the relatively long extension of the closing parts  74  in the direction of the housing  12 . Depending on the screwing-in depth of the connection modules  92 , the pivot angle of the pivoting part  20  can consequently be changed within a relatively large range. To permit simple and easy adjustment of the pivot ranges, the connection modules  62 ,  64  and  92  have screwing-on or unscrewing means in the form of a hexagonal socket  94 . 
     FIG. 3  shows a view in the direction of the arrow III onto the pivoting device  10  in accordance with  FIG. 1  or the pivoting device  90  in accordance with  FIG. 2 . This view shows means  100  for fixing the connection modules  64  or  92  in their axial position. The fixing means  100  comprise a fixing pin  102  which is retained in the housing  12  and designed like a screw bolt comprising an eccentric head and a clamping part  106  which is penetrated by the fixing pin  102 . The eccentric head of the fixing pin  102  is thereby seated in a cylindrical recess  104  in the clamping part  106 . The clamping part  106  has two clamping surfaces  108  which abut against the respective surfaces of the connection modules  64 ,  92 . When the fixing pin  102  is turned, the clamping part  106  is clamped between the two connection modules  64 ,  92  by the eccentric head. The eccentric head of the fixing pin  102  thereby acts against the wall of the cylindrical recess  104  of the clamping part  106  to fix the connection modules  64 ,  92  via the clamping surfaces  108 . To release fixing, the fixing pin  102  is turned through between a quarter and a half of a rotation. The connection modules  64 ,  92  are thereby fixed in a simple and yet very effective manner. 
   To retain the fixing pin  102  in an axial direction, the fixing pin may have a radial circumferential groove into which a retaining pin engages that extends transversely to the longitudinal axis of the fixing pin  102  in such a manner that the fixing pin  102  is held such that it can be rotated but not displaced in its axial direction. 
   The pivoting device  110  of  FIG. 4  comprises a housing  12  corresponding to the pivoting devices  10  and  90  with corresponding components which have reference numerals corresponding to the pivoting devices  10 ,  90  of  FIGS. 1 and 2 . The free end faces of the cylinder tubes  24 ,  28  of the pivoting device  10  comprise connection modules  112 , each having one abutment part  114  which can be displaced to two positions and can be locked in its axially inner position. The working pistons  14 ,  16  and therefore the pivoting part  20  can thereby be moved to a predetermined intermediate position. The abutment part  114  facing the pressure side  42  is thereby in the locked intermediate position. 
   The connection modules  112  each have a sleeve  116  accommodated in a common additional housing  113 , in which the piston-like abutment part  114  is disposed in an axially displaceable manner. Towards this end, a pressure chamber  118  is provided on the side of the abutment part  114  facing away from the respective working piston  14 ,  16 . The pressure chamber  118  is pressurized or pressure-relieved via a pressure connection  119 . The air is thereby guided into or out of the pressure chamber  118  via a radially outer circumferential annular groove  123  on the respective sleeve  116  and via openings which are connected to the groove  123  and, in particular, have the form of bores  125 . 
   Upon pressurization of the pressure chamber  118 , the abutment part  114  is moved into the intermediate position. Towards this end, the abutment part  114  moves towards the respective working piston  14 ,  16  until its collar-like abutment  132  strikes against an abutment  134  on the sleeve side. Due to pressurization of the pressure chamber  118 , a locking piston  120  which is disposed to be axially displaceable on the inner side of the abutment part  114  is moved against the spring force of a pressure spring  122  towards the respectively associated working piston  14 ,  16 . The locking piston  120  has inclined guiding surfaces  124  which adjoin a receptacle  126  for locking balls  128 . In the initial position, the locking balls  128  are partially disposed in the receptacles  126  and partially in openings  129  extending in a radial direction and provided on the abutment part  114 . The wall of the regions of the abutment part  114  surrounding the openings  129  thereby have approximately half the ball diameter. Preferably several locking balls  128  disposed at equal separations from each other are provided over the periphery of the abutment part. 
   Upon displacement into the locking position, the balls  128  are forced from their receptacles  126  via the inclined guiding surfaces  124  in a radial outer direction into locking receptacles  130  provided on the inner side of the sleeve  116 . The locking receptacles  130  extend in radial directions approximately by half a ball diameter. The locking receptacles  130  can either be formed as individual receptacles or as one single circumferential, groove-like receptacle. 
   The geometries of the receptacles  126 , the locking balls  128 , the openings  129  and the locking receptacles  130  are designed such that, in the locked intermediate position, axial forces exerted by the respective working piston  14 ,  16  or by the damping means  76  on the respective abutment part  114  are diverted via the locking balls  128  into the sleeve  116  and from the sleeve via screw connections between the sleeve and the housing  12 , to the housing  12 . 
   The locked intermediate position is maintained until the pressure chamber  118  is pressurized. If the pressure chamber  118  is pressure-free, the locking piston  120  is initially displaced in an axial outer direction via the pressure spring  122 . The locking balls  128  thereby drop into the receptacles  126 . Through movement of the working piston  14 ,  16  against the abutment part  114 , the abutment part  114  including locking piston  120  and locking balls  128  are carried along in an axial outward direction until the abutment part  114  has reached its initial position followed by pivoting of the pivoting part  20  into the initial position. 
   In consequence thereof, the intermediate position can advantageously be activated or deactivated through pressurization or pressure-relieve of the pressure chamber  118 . One particular advantage of the described embodiment is that return of the abutment part  114  is possible even under axial loads through releasing the pressure in the pressure chamber  114 . 
   The described pivoting devices  10 ,  90  and  110  permit flexible use since they all comprise identical housings  12  or identical cylinder tubes. Depending on the application of the pivoting devices, corresponding connection modules  62 ,  64 ,  92  or  112  may be provided. The connection modules can be exchanged with little expense and using simple tools. 
   All the features shown in the description, the claims and the drawing may be essential to the invention either individually as well as in arbitrary combination.