WORKING DEVICE HAVING A HYDRAULIC CYLINDER AND MANUAL WORKING DEVICE SUCH AS A PLIERS OR A PRESS

Abstract

A hydraulically actuated working device having a hydraulic cylinder, a hydraulic piston that can be displaced in the hydraulic cylinder, a drive unit part which has a motor and a pump, and a hydraulic line leading to the hydraulic cylinder. The drive unit part is designed in an electrically insulating manner, to provide an electrically insulating separating layer, which passes through the working device in a crossing manner for electrical separation from the working device part with respect to an end of the hydraulic piston facing the drive unit part. The hydraulic line is guided through the separating layer, thereby also forming a partial region of the hydraulic line made of an electrically insulating material.

Claims

1. A hydraulically actuated working device (1) having a hydraulic cylinder (13), a hydraulic piston (12), which can be displaced in the hydraulic cylinder (13), a drive device part (2), which has a motor (9) and a pump (8), and a hydraulic line (16) leading to the hydraulic cylinder (13), characterized in that the hydraulic cylinder (13) is formed in an electrically insulated manner with respect to the drive device part (2), for which purpose an electrically insulating separating layer (19) is provided, which passes through the working device (1) in a crossing manner for the electrical separation from the working device part (2) in the region of an end of the hydraulic cylinder (13) facing the drive device part (2), wherein the hydraulic line (16) is guided through the separating layer (19) while also forming a partial region (26) of the hydraulic line (16) made of an electrically insulating material.

2. The working device according to the features of the preamble of claim 1 or according to claim 1, characterized in that the hydraulic cylinder (13) is formed in an electrically insulating manner with respect to the drive device part (2), and that an electrically insulating piston head (36) is provided with respect to the hydraulic piston (12), and/or the hydraulic piston (12) can only be displaced so far in the direction of the drive device part (2) that a largest distance (a) between a point of the piston head (36) and an electrically conductive region of the drive device part (2) exceeds a distance, which is necessary for the electrical insulation.

3. The working device according to the features of the preamble of claim 1 or according to one of claim 1 or 2, characterized in that the hydraulic cylinder (13) is formed in an electrically insulated manner with respect to the drive device part (2), for which purpose an electrically insulating separating layer (19) is preferably provided, which passes through the working device (1) in a crossing manner for the electrical separation from the working device part (2) in the region of an end of the hydraulic cylinder (13) facing the drive device part (2), and that the hydraulic line (16) consists at least over an essential portion of its length of an electrically insulating material.

4. The working device according to the features of the preamble of claim 1 or according to one of claims 1 to 3, wherein the working device (1) has a handle region (3) and a working head (4), which is separate from the handle region (3), characterized in that the handle region (3) is separate from the working head (4) by means of a radial collar (20), which protrudes radially over the handle region (3), or which is separate from the working head (4) by means of a tapering region (48), which adjoins the handle region (3) on a working head side and which extends axially, wherein a radial level of protrusion (v) and an axial level of extension (e) of the tapering region (48) is as thick as a finger or more.

5. The working device according to the features of the preamble of claim 1 or according to one of claims 1 to 4, characterized in that a seal (51) with respect to ingress of a fluid from the outside into the hydraulically actuated working device (1) is formed in a joining region (53) of the hydraulic cylinder (13), and that with respect to a hydraulic medium pressure, which is possible in the joining region (53) and develops from the inside, a relief valve (52) for discharging hydraulic medium (15) to the outside is provided.

6. The working device according to one of claims 1 to 5, characterized in that the hydraulic line (16) is formed metallically and has an inner separating layer made of an electrically insulating material.

7. The working device according to one of the preceding claims, characterized in that a separating layer (19) made of an electrically insulating material is also provided on the outer side of the hydraulic line (16).

8. The working device according to one of the preceding claims, characterized in that the separating layer (19) provided on the outer side of the hydraulic line (16) continues all the way into an outer region of the hydraulic cylinder (13).

9. The working device according to one of the preceding claims, characterized in that the separating layer (19) provided on the outer side of the hydraulic line (16) and the inner separating layer (19) are formed integrally.

10. The working device according to one of the preceding claims, characterized in that the separating layer (19) provided on the outer side of the hydraulic line (16) and the inner separating layer (19) guided through the hydraulic line (16) consist of the same material.

11. The working device according to one of the preceding claims, characterized in that an electrically insulating separating layer (19) is provided on the inner side of the wall of the hydraulic cylinder (13).

12. The working device according to one of the preceding claims, characterized in that the separating layer (19) provided on the inner side of the wall of the hydraulic cylinder (13) is guided to the outside beyond the outer region of the hydraulic cylinder (13).

13. The working device according to one of the preceding claims, characterized in that the separating layer (19) forms the wall (18) of the hydraulic cylinder (13) as a whole.

14. The working device according to one of the preceding claims, characterized in that the separating layer (19) consists of an electrically insulating plastic.

15. The working device according to one of the preceding claims, characterized in that the separating layer (19) consists of an electrically insulating ceramic material.

16. The working device according to one of the preceding claims, characterized in that with respect to the ingress of fluid, the seal (51) is formed by an annularly continuous sealing element (54, 54).

17. The working device according to one of the preceding claims, characterized in that the relief valve (52) is formed by using the sealing element (54, 54).

18. The working device according to one of the preceding claims, characterized in that over its circumference, the sealing element (54, 54) for forming the relief valve (52) has a partial region (61), which can be moved into a position, which opens the relief valve (52), by means of the hydraulic medium pressure.

19. The working device according to one of the preceding claims, characterized in that the movability of the partial region (61) is provided by means of a recess (57) in a sealing seat (58) of the hydraulic cylinder (13), which receives the sealing element (54, 54), or in a section of the drive device part (2), which cooperates with the hydraulic cylinder (13) in the joining region (53).

20. The working device according to one of the preceding claims, characterized in that the seal (51) is provided between an electrically conductive housing section of the working device part (2) or of the hydraulic cylinder (13) and the electrically insulating separating layer (19).

21. The working device according to one of the preceding claims, characterized in that two seals (51) are provided against ingress of fluid from the outside and/or for forming relief valves (52).

22. An assembly (A) for sealing an intermediate space (69) between two parts (T.sub.1 and T.sub.2) against ingress of a medium from the outside to the inside, wherein an internally higher pressure can simultaneously be reduced by means of the assembly (A), wherein the assembly (A) further has a closed annularly circumferential sealing element (54, 54) consisting of elastic material, which, in an initial state, bears sealingly over its entire circumference under pre-load into a sealing position against the two parts (T.sub.1 and T.sub.2), wherein, in addition, a movement of the sealing element (54, 54) to the outside and lift-off from one of the parts (T.sub.1 and T.sub.2) is released over at least a portion of the circumference.

23. The assembly according to claim 22, characterized in that the sealing element (54, 54) spans a plane (B).

24. The assembly according to one of claim 22 or 23, characterized in that the movement of the sealing element (54, 54) is provided in the plane (B) to the outside.

25. The assembly according to one of claims 22 to 24, characterized in that the movement of the sealing element (54, 54) is provided perpendicular to the plane (B).

26. The assembly according to one of claims 22 to 25, characterized in that the movement of the sealing element (54, 54) perpendicular to the plane (B) is overlapped by a movement of the sealing element (54, 54) in the plane (B) to the outside.

27. The assembly according to one of claims 22 to 26, characterized in that the parts (T.sub.1 and T.sub.2) are immovable to one another.

28. The assembly according to one of claims 22 to 27, characterized in that an inclined surface (70), via which the sealing element (54, 54) can move in response to a pressure reduction, optionally within a certain circumferential region, is formed at one of the parts (T.sub.1 or T.sub.2).

29. The assembly according to one of claims 22 to 28, characterized in that the movement of the sealing element (54, 54) perpendicular to the plane (B) is only released in one direction.

30. The assembly according to one of claims 22 to 29, characterized in that the movement of the sealing element (54, 54) perpendicular to the plane (B) is only released over a portion of the circumference.

31. The assembly according to one of claims 22 to 30, characterized in that the pre-loading is predetermined by means of a circumferential length of the sealing element (54, 54).

32. The assembly according to one of claims 22 to 31, characterized in that the pre-loading is predetermined by a gap width between the parts (T.sub.1 and T.sub.2).

33. The assembly according to one of claims 22 to 32, characterized in that to release the movement of the sealing element (54, 54), a contact surface, which is provided transversely to the extension of the plane, is formed at one of the parts (T.sub.1 or T.sub.2) only over a portion of the circumference.

34. A manual working device (1), preferably hydraulically actuated working device according to one of claims 1 to 33, such as pliers or a press, in particular pliers or a press, which can be electro-hydraulically actuated or via an electric motor, having a sensor (40) for detecting an electric voltage (S), assigned to a working head (4) of the manual working device (1), characterized in that the sensor (40) is formed for the radio connection with a receiver (43) outside of the manual working device (1).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0090] The invention will be described below on the basis of the enclosed drawings, which, however, only represents exemplary embodiments. A part, which is described only based on one of the exemplary embodiments, and which is not replaced by another part in a further exemplary embodiment due to the special feature emphasized therein, is thus also described for this further exemplary embodiment as an at least possible existing part. In the drawing:

[0091] FIG. 1 shows a working device in a first embodiment in perspective illustration;

[0092] FIG. 2 shows the working device according to FIG. 1 in a partially cut side view;

[0093] FIG. 3 shows the enlargement of the region III in FIG. 2;

[0094] FIG. 4 shows the sectional illustration according to FIG. 3, relating to a second embodiment;

[0095] FIG. 4a shows the enlargement of the region IVa in FIG. 4;

[0096] FIG. 5 shows a perspective illustration of a working device in a third embodiment;

[0097] FIG. 6 shows the working device according to FIG. 5 in a side view;

[0098] FIG. 7 shows the enlargement of the region VII in FIG. 6 in a sectional illustration;

[0099] FIG. 8 shows a fourth embodiment in an illustration according to FIG. 3;

[0100] FIG. 9 shows a sectional illustration according to FIG. 4, relating a further embodiment;

[0101] FIG. 10 shows an illustration corresponding to FIG. 4, relating to an alternative embodiment;

[0102] FIG. 11 shows a sectional illustration essentially corresponding to FIG. 9, relating to a further embodiment;

[0103] FIG. 12 shows the enlargement of the region XII in FIG. 11, in addition to a corresponding magnified illustration;

[0104] FIG. 13 shows the enlarged section according to the line XIII-XIII in

[0105] FIG. 12;

[0106] FIG. 14 shows a sectional illustration according to FIG. 12, in addition to a corresponding magnified illustration;

[0107] FIG. 15 shows the enlarged section according to the line XV-XV in

[0108] FIG. 14;

[0109] FIG. 16 shows a working head of the working device with a working cylinder as well as a separating layer with two sealing elements and one fixed part in a perspective exploded illustration;

[0110] FIG. 17 shows the separating layer in a further perspective illustration, in addition to a magnified enlarged illustration;

[0111] FIG. 18 shows a working device in further embodiment;

[0112] FIG. 19 shows a working device in a further embodiment;

[0113] FIG. 20 shows a manual working device having a sensor for detecting an electric voltage and a radio connection to a receiver.

DESCRIPTION OF THE EMBODIMENTS

[0114] What is illustrated and described, initially with reference to the illustration in FIG. 1, is a working device 1, here in the form of an electro-hydraulically actuatable cutting device in rod-like embodiment. A working device 1 formed in such a way is known from the above-cited WO 2003/084719 A2 (U.S. Pat. No. 7,254,982 B2). The content of this WO-document or US-document, respectively, is hereby included in its entirety into the disclosure of the present invention, also for the purpose of including features of this WO-document or US-document, respectively, into claims of the present invention.

[0115] As can further be seen in an exemplary manner in the illustration in FIG. 18, a working device 1 of this type can, for example, also be provided as pressing device in gun-like embodiment. A working device 1 of this type is known from the above-cited WO 2014/108361 A1 (US 2015/0364889 A1). The content of this WO-document or US-document, respectively, is hereby also included in its entirety into the disclosure of the present invention, also for the purpose of including features of this WO-document or US-document, respectively, into claims of the present invention.

[0116] The manual device 1 initially and essentially has a drive device part 2, which, in the case of a rod-like embodiment according to FIG. 1, but also in the case of a gun-like embodiment according to FIG. 18, can simultaneously form a handle region 3. In the case of a gun-like embodiment of the working device 1 according to the illustration in FIG. 18, the handle region 3 extends essentially transversely to the drive device part 2.

[0117] Towards a free end of the working device, a working head 4, which can have two cutting jaws 45 in the exemplary embodiments illustrated in FIGS. 1 and 5, adjoins the drive device part 2. The respectively illustrated working head 4 is only exemplary. The working head according to FIG. 9 can thus, for example, also have pressing jaws 46. The working head 4 is preferably mounted in an exchangeable manner, more preferably by means of a separation in the region of the hydraulic cylinder 13, see also further below. In addition, and preferably, the working head 4 can be mounted in a freely rotatable manner around a working head longitudinal axis x relative to the drive device part 2 or to the corresponding receptacle 23, respectively, for the working head 4.

[0118] With reference to, for example, the illustration in FIG. 2, the connection with the object described in the mentioned EP 1 519 813 B3 can be seen for instance with respect to a return valve 5, a tank 6, and a pump tappet 7. As a whole, it can also be seen in this context that a hydraulic medium pump 8 and an electric motor 9 for the hydraulic medium pump 8 can be provided in serial arrangement. The electrical supply in particular of the electric motor 9, but in addition also of a non-illustrated control unit and of further electrical components in the working device, is provided by means of the arrangement of an accumulator 10.

[0119] The handle region 3 is formed for the usual gripping of the working device housing by means of a hand. Assigned to the handle region 3, an actuating button 11 is provided in an ergonomically favorable manner.

[0120] In particular the above-mentioned components return valve 5, tank 6, hydraulic medium pump 8 with pump tappet 7, electric motor 9, the control unit, and further electrical components, as well as the actuating button 11, as a whole are preferably parts of the drive device part 2.

[0121] A hydraulic piston 12 is provided for displacing a working jaw, for example cutting jaw 45 or pressing jaw 46, in the working head 4. Said hydraulic piston can be displaced along the axis x in a hydraulic cylinder 13 against the force of a restoring spring 14.

[0122] When actuating the actuating button 11 accordingly via the pump tappet 7 during the operation of the working device 1, hydraulic medium 15 is pumped via a hydraulic line 16 into the hydraulic cylinder 13, in order to correspondingly impinge the piston front face, which faces the hydraulic medium 15.

[0123] The hydraulic piston 12, preferably with respect to a divisibility according to the mentioned EP 1 084 798 A2 or U.S. Pat. No. 6,718,870 B1, respectively, with respect to a hydraulic piston rod, the hydraulic cylinder 13, or in terms of the mentioned divisibility preferably a part of the hydraulic cylinder 13 can be parts of the working head 4.

[0124] According to the embodiments of FIGS. 1 to 4, the hydraulic cylinder 13 can have a portion of a hydraulic line 16, which opens out into it and which is formed as neck 17, which runs concentrically to the axis x, in the exemplary embodiment. This neck 17 is thus of reduced diameter with respect to the wall 18 of the hydraulic cylinder 13.

[0125] A continuing part 24 of the hydraulic line 16 is plug-guided or plug-mounted in the neck 17. A lining part 26 made of an electrically insulating material is arranged in the interior of the neck 17 and also extends in this overlap region with respect to the section of the neck 17, which is arranged in an overlapping manner to the continuing part 24, and thus provides an electrically insulating separation to the continuing part 24.

[0126] The hydraulic cylinder 13 is surrounded by an electrically insulating separating layer 19. The separating layer encompasses the hydraulic cylinder 13 in the region of the wall 18 of the hydraulic cylinder 13 over the entire circumference. In addition, the separating layer also encompasses the region of the neck 17, including the transition of the wall 18 into the neck 17.

[0127] The separating layer 19 as well as the lining part 26 and parts and regions also listed further below, which act in an electrically insulating manner in terms of the invention, can consist of a ceramic material or, in the alternative, and mostly preferred, of an electrically insulating plastic.

[0128] The separating layer 19 undergoes a continuation through the lining part 26 in the interior of the hydraulic line 16, by means of a molding of the lining part 26, which also engages over a free end of the neck 17. The separating layer 19 is formed in its extension along the neck 17 or also along and preferably partially nested in the continuing part 24, respectively, thus until it overlaps with the lining part 26.

[0129] Assigned to a free end of the neck 17, a plug-mounting with respect to the separating layer 19 of the hydraulic cylinder 13 can be provided, for example, by means of a retaining ring. Due to the fact that the separating layer 19 is positively connected, preferably threadedly connected, to a fixed part wall of the working device part, the mounting as a whole is attained thereby.

[0130] In the case of the illustrated exemplary embodiment and thus preferably, a section of the separating layer 19 surrounding the wall 18 of the hydraulic cylinder 13 is provided with a plate-like radial collar 20. Starting at the neck 17, the separating layer 19 extends beyond the region of the radial collar 20 (see in particular FIGS. 3, 4, and 9).

[0131] As, for example, in the exemplary embodiment illustrated in FIG. 4, the radial collar 20 can have a radial extension, viewed based on the axis x, which can essentially correspond to the radial extension of the wall section 47 of the working head 4, adjoining the radial collar 20.

[0132] As can further be seen from the illustration in FIG. 9, in addition also according to the illustration in FIG. 8, the radial collar 20 can, however, also extend radially beyond this wall section 47, for example with a radial level of protrusion beyond the wall section 47 of 5 mm to 15 mm, or 20 mm, or more millimeters.

[0133] In particular according to the exemplary embodiments in FIGS. 4 and 9, in addition also according to FIG. 7, a tapering region 48 can result between the handle region 3 and the handle region 3 to the radial collar 20 limiting the working head 4. Said tapering region can, and preferably, be limited in the axial direction, on one end by means of the drive device part 2 or the handle region 3, respectively, and axially on the other end preferably by means of the radial collar 20, optionally by means of an electrically insulated radial section of the wall section 47, for forming such a radial collar 20.

[0134] A trench, which is preferably circumferential with respect to the axis x, thus results in particular between the handle region 3 and the working head 4, for preventing a slipping of the hand gripping the working device from the handle region 3 in the direction of the working head 4.

[0135] For this purpose, the tapering region 48 is provided in a suitable manner with an axial level of extension e between the front faces of the handle region 3 facing one another or of the drive device part 2 and the radial collar 20, respectively, which level of extension e corresponds to at least the thickness of a finger, thus preferably at least 8 mm, in addition further preferably more than 8 mm, for example up to 20 or 30 mm, or more.

[0136] The radial level of extension v of the radial collar 20, via the section of the separating layer 19 connecting the working head 4 to the handle region 3 in a neck-like manner, or of the hydraulic cylinder 13, respectively, and thereby forming the base of the tapering region 48, can, and preferably, also correspond to at least the thickness of a finger, more preferably 8 mm or more, thus optionally up to 15 or 20 mm, or more.

[0137] In the region of the section of the separating layer 19 encompassing the neck 17, the separating layer 19 is completely encompassed circumferentially on the outer side of the wall by the already mentioned fixed part 21, which is pot-shaped as a whole and which simultaneously also forms the already mentioned part of the hydraulic line in the case of the exemplary embodiment and thus preferably. The fixed part 21 as well as the hydraulic cylinder 13 itself, including the neck 17, consists of a metallic material, preferably of steel. The circumferential fixed part wall 22 has an external thread, for cooperation with an assigned internal thread of the receptacle 23 provided in the drive device part 2.

[0138] As already described, the fixed part wall 22 is in threaded engagement on the inner side with the separating layer 19, which also surrounds the neck 17 in this region.

[0139] At the continuing part 24, the fixed part 21 has a base, from which a metallic section 25 starts centrally, passed through centrally by the axis x, which thus concretely forms the already mentioned part of the hydraulic line. In the region of its free end, the section 25 protrudes into the neck 17 by radially spacing apart the section outer surface from a neck inner surface. As already described, the radial spacing is filled by the lining part 26, and the insulation is thus attained.

[0140] On the inner side, following the axis x, the separating layer 19 is continued by the lining part 26 for forming a section of the hydraulic line 16, wherein the lining part 26 accordingly also consists of an electrically insulating material. The lining part 26 abuts on the neck 17 on the inner side of the wall and centrally forms an already mentioned part of the hydraulic line, which continues in the axial direction into the section of the hydraulic line of the fixed part-side metallic section 25.

[0141] Assigned to the free end of the neck 17, the lining part 26 has the already mentioned radial widening 27. This radial widening 27 underpins a free front face of the neck 17.

[0142] According to the illustration in FIGS. 3 and 4, the separating layer 19 extends beyond the section, which is in threaded engagement with the fixed part 21, by encompassing the radial widening 27.

[0143] According to the illustration in FIG. 3, the surface areas of the base of the continuing part 24 and of the fixed part wall 22, which are directed in the direction of the hydraulic cylinder 13 or to the inside, respectively, can be covered with an electrically insulating element 28, for example plastic element.

[0144] The multi-part design of the fixed part 21, which can be seen in FIG. 3 and FIG. 4, can be provided solely due to a simplified producibility. These parts can generally also be integrally connected to one another.

[0145] More generally, an insulation layer results, which crosses the axis x and which is essentially oriented on an insulation plane E, and which electrically insulates the hydraulic cylinder 13 and thus the working head 4 as a whole completely with respect to the drive device part 2. The insulation layer preferably runs in a U-shaped manner, viewed in a cross section, wherein, more preferably, a pass-through through the hydraulic line 16 is provided in the region of the U-web.

[0146] The electrical insulation in the embodiments of FIGS. 1 to 4 is in particular provided by the nesting of the electrically insulating materials of the separating layer 18 and of the hydraulic line partial region 26, in which nesting the free end of the hydraulic cylinder 13 is received essentially completely in the region of the neck 17 thereof.

[0147] The hydraulic medium 15 provided in the hydraulic line 16, in particular in the duct of the electrically insulating partial region 26, acts in an electrically insulating manner, so that a flashover, for example from the metallic hydraulic cylinder 13 through the duct of the hydraulic line 16 to the metallic fixed part 21 and via this to the drive device part 2 is also prevented.

[0148] In the further embodiment illustrated in FIG. 7, the hydraulic cylinder 13 is formed so as to essentially be split into two in the longitudinal extension along the axis x, consisting of consisting of a working head-side cylinder part 29 and a cylinder part 30, which is arranged essentially in the axial extension to this cylinder part 29. The cylinder part 30 is thereby part of the drive device part 2, in particular fixedly arranged on the latter. A slide displacements of the piston head 36, to which pressure can be applied, along the axis x is preferably provided only in the region of the cylinder head 30.

[0149] The electrical insulation of the working head 4 with respect to the drive device part 2 takes place here as a result of a preferred inner lining of the hydraulic cylinder 13, in particular of the cylinder part 30 on the drive device part side. A separating layer 19 is thus provided, which initially and essentially completely circumferentially covers the inner cylinder surface, which cooperates with the circumferential hydraulic piston wall.

[0150] In the end facing the working head 4, the cylinder part 30 widens in a sleeve-like manner into a radial widening 31. In the cross section according to FIG. 7, the separating slayer 19 follows this step-like widening and covers the step wall, which results in the step region and which extends transversely to the axis x, as well as the widening wall of the radial widening 31, which adjoins subsequently and is which directed to the inside, so as to finally extend on the front face of the radial widening 31 with a collar 32 radially to the outside beyond the annular front face of the radial widening 31 facing the working head 4. With respect to the largest diameter of the radial widening 31, the collar 32 is of increased diameter.

[0151] A radial thickness, which is significantly larger compared to the further overlap regions, for example on the inner side of the wall of the cylinder surface, is provided in the section 44 of the separating layer 19, which runs circular cylindrically to the axis x in the radial widening region of the cylinder part 30. In this connection, an approximately 5-fold thickness can thus be provided compared to the section of the separating layer 19, which cooperates with the circumferential piston surface.

[0152] The separating layer 19, which is thus pot-shaped as a whole and which is preferably integrally molded with the collar 32, can, and as is illustrated, be mounted in the region of the radial widening 31 as a result of a threaded engagement with the cylinder part 30.

[0153] Facing the drive device part 2, the separating layer 19 extending on the inner side of the wall of the cylinder part 30, supports a base 33, which extends transversely to the axis x in the hydraulic cylinder 13, having a thickness viewed in the axial direction, which can correspond to a multiple, for example 4 times to 6 times the thickness of the separating layer 19 on the inner side of the wall of the cylinder part 30.

[0154] Centrally passed through by the axis x, the base 33 is provided with an opening 34, which forms a part of the hydraulic line.

[0155] The lower surface of the base 33 facing the hydraulic cylinder base 35 can be spaced apart from the hydraulic cylinder base 35 in the axial direction, for instance with 0.5 times to 0.75 times the level of thickness of the base 33, viewed in the same direction. A direct contact is also possible in this respect.

[0156] The surface area of the base 33 facing away from the hydraulic cylinder base 35 serves as stop for the hydraulic piston 12, in particular the piston head 36 thereof, whereby, in the initial position illustrated in FIG. 7, in which the hydraulic piston 12 is maximally displaced in the direction of the drive device part 2, a clearance measurement a between the lower surface of the piston head 36, which is not electrically insulated by means of a separating layer or the like, is not maintained in the region of the base opening 34 and the next electrically conductive region of the drive device part 2here of the hydraulic cylinder base 35, which minimum distance dimension a is preferably at least 10 to 12 mm, more preferably optionally approximately 15 mm. A necessary distance dimension between an electrically conductive region of the drive device part 2 and an optionally live section of the working head 4 is thus provided. A sufficient flashover resistance thus results.

[0157] For the arrangement of the working head 4 on the drive device part 2, the head-side cylinder part 29 is in screw-connection with the separating layer 19 in the region of the section 44 thereof. In the assigned position, optionally so as to limit abutment, the annular front face of the cylinder part 29, which faces the drive device part 2, moves against the section 44 of the separating layer 19, which lines the step-like widening of the cylinder part 30.

[0158] At least a distance dimension a of between 10 and 12 mm, preferably up to at least 15 mm, which ensures the flashover resistance, is also provided by the collar 32 between an optionally live section of the working head 4for example the housing section 37 in FIG. 7and the next possible electrically conductive section of the drive device part 2here the radial widening 31.

[0159] According to the illustrations in FIGS. 4, 8, and 9, the hydraulic piston 12, in particular the piston head 36 thereof, which cooperates with the hydraulic medium 15, can consist of an electrically insulating material, for example of ceramic, as a further example of a pressure-resistant plastic.

[0160] According to the illustration in FIG. 8, the hydraulic cylinder 13, in particular the corresponding cylinder wall, and more preferably also the hydraulic cylinder base 35, can further consist directly of an electrically insulating material. A material reinforcement, which is overmolded with plastic, for example, can hereby be provided, for example in the region of the hydraulic cylinder wall 38. In contrast, the hydraulic cylinder wall 38 alone can also be formed from a pressure-resistant plastic, such as, for example, GRP or carbon fiber-reinforced plastic, for example in the case of low-pressure systems.

[0161] The hydraulic cylinder base 35 is provided with a central bore for forming a section of the hydraulic line 16. The thickness of the hydraulic cylinder base 35, viewed in the axial direction, preferably corresponds at least to the necessary distance dimension a of between 10 and 12, more preferably approximately 15 mm, further in particular in those cases, in which the piston head 36 is made of an electrically conductive, in particular metallic material.

[0162] In the case of this embodiment, an electrically insulating radial collar 20 is also provided, which, in the embodiment with a sleeve-like section 39, is attached on the outer side of the wall to the tubular cylinder wall of the hydraulic cylinder 13, which likewise consists of electrically non-conductive material. In the alternative, however, this can also be an integral embodiment in this respect.

[0163] In the radial direction, the radial collar 20 preferably extends beyond the radial dimension of the working head 4 into a region within the necessary distance a to the radial collar 20, so that a flashover from the preferably metallic housing section 37 of the working head 4 to the metallic housing of the drive device part 2 is also prevented.

[0164] In a further embodiment, the illustrations in FIGS. 11 to 17 show a seal 51, when arranging a separating layer 19 between the hydraulic cylinder 13 and the drive device part 2, as well as a relief valve 52 in the joining region 53 of the hydraulic cylinder 13. The resulting assembly A serves in particular for sealing an intermediate space 69 between two parts T.sub.1 and T.sub.2, here between the separating layer 19 (part T.sub.1) and the fixed part wall 22 or the hydraulic cylinder 13 (part T.sub.2), respectively.

[0165] The seal 51 can, and preferably, be formed thereby by an annularly continuous sealing element 54, for example in the form of an O-ring. In addition, this sealing element 54 can be aligned concentrically to the axis x.

[0166] As can further be seen in particular from the illustration in FIG. 11, two sealing elements 54 of this type can be provided in concentrical position, but spaced apart from one another in the axial direction, wherein a first sealing element 54 can be positioned between the separating layer 19 and the fixed part 21, in particular the fixed part wall 22, and the further sealing element 54 can essentially be provided between the outer wall of the hydraulic cylinder 13 and the inner wall of the separating layer 19, which encompasses this region of the hydraulic cylinder 13.

[0167] Seals 51 and relief valves 52 can thus be provided in two regions, wherein in a possible, in addition also preferred embodiment, the sealing element 54 or 54, respectively, of the seal 51 can simultaneously also be used to form the relief valve 52, wherein the sealing element 54 or 54, respectively, rests in its respective sealing seat in a common initial position under pre-loading. Each sealing element 54 and 54 thereby spans a geometric plane B, which runs transversely to the axis x.

[0168] As is also partially embodied in the above-described exemplary embodiments, the separating layer 19 can encompass the end of the hydraulic cylinder 13, which encompasses the working head 2 in a pot-like manner. The radial collar 20 can thereby be molded on the outer side, wherein the pot wall 55 of the separating layer 19 can extend beyond the plane of the radial collar 20 in the direction of the working head 4 (see also FIG. 11).

[0169] In the illustrated exemplary embodiment, the sealing element 54 is assigned to this pot end of the separating layer 19, which preferably extends within the wall section 47. This sealing element 54 can be encompassed by this section of the pot wall 55 of the separating layer 19 preferably over the entire circumference, wherein the sealing element 54 can further rest in a groove 56 of the wall 18 of the hydraulic cylinder 13, which is concentrically circumferential to the axis x.

[0170] With respect to its cross section according to FIG. 11, the groove 56 can initially and essentially be designed in such a way that the sealing element 54 can be supported radially to the inside on the groove base 56, and in each case axially to the outside on the groove walls. Radially to the outside, the sealing element 54 can seal against the facing inner surface of the pot wall 55 of the separating layer 19.

[0171] As can in particular be seen from the enlarged illustrations in FIGS. 12 and 13, a recess 57 results, viewed over the circumference, which is formed to be limited in the circumferential direction in the wall of the hydraulic cylinder 18 and which has a larger radial depth compared to the groove 56 and the sealing seat 58 formed by the groove 56. Viewed in the axial direction, this recess 57 can extend, adjoining the sealing seat 58 and running into the latter, in the direction of the working head 4. Due to the formation of this recess 57, the contact surface for the sealing element 54 is interrupted on the side of the hydraulic cylinder 13.

[0172] As can be seen, for example, from FIG. 13, the recess 57 can extend over an angle of, for example 5 to 20 degrees, as a further example 10 to 15 degrees, in the circumferential direction. In this recess region, the surface area of the sealing element 54, which faces away from the hydraulic line 16, is essentially exposed, can thus optionally yield elastically from the inside to the outside into the space of the recess 57 with this partial region 61 in response to a pressure load acting on the sealing element 54 (see also enlarged illustration in FIG. 12).

[0173] In the radial assignment to the recess 57, the free end region of the pot wall 55 of the separating layer 19 can additionally have an open-edged cutout 59 (see also FIG. 13 here).

[0174] According to the proposed embodiment, hydraulic medium between the outer wall of the hydraulic cylinder 13 and the inner wall of the pot-like separating layer 19 can reach in the direction of the axially front end of the separating layer 19 in response to an excessive hydraulic pressure, which optionally builds up in the device. For this purpose, a path 60, for example in the form of a groove-like depression, can be predetermined, for example on the outer side of the wall of the hydraulic cylinder 13, which path 60 leads to the partial region 61 of the sealing element 54 assigned to the recess 57. The hydraulic medium, which pushes against the sealing element 54 from the inside to the outside in this case, can lead to a movement of the corresponding partial region 61 of the sealing element 54 in the direction of the recess 57 and thus essentially perpendicular to the geometric plane B of the sealing element 54 in the region of the recess 57 when exceeding a predetermined pressure value, so that, according to the enlarged illustration in FIG. 12, a discharge path 62 past the partial region 61 can result. An incremental discharge of hydraulic fluid can thus be attained via the relief valve 52, which is designed in this way.

[0175] With the reduction of the pressure via the hydraulic medium, the sealing element 54 automatically restores due to the provided elasticity and pre-load of the sealing element 54, for sealingly resting in the sealing seat 58.

[0176] A loading of the sealing element 54 from the outside, for example in response to a loading from the outside by means of water or the like, the sealing element 54 is pressed into the sealing seat 58 to form a seal 51, so that such a loading optionally still supports the effect of the seal 51.

[0177] According to the illustrated exemplary embodiment, the further sealing element 54 can be received in a sealing seat 58 formed on the front face of the fixed part wall 22. This sealing seat 58 can be formed in the form of a groove 56, which is both axially and radially open, wherein, in a cross section according to, for example, FIG. 14, in which cross section the axis x presents itself as a line, the groove base 63 can be formed here as sloping inclined surface 70.

[0178] In the unloaded state, the sealing element 54, which rests in the sealing seat 58 designed in this way, can preferably seal against a facing front face 64 of the pot-shaped separating layer 19 as well as in particular against the groove base 63 and a rearward groove wall.

[0179] With respect to a hydraulic medium discharge when exceeding a hydraulic medium pressure, a discharge path 65 can result essentially between the fixed part 21 or the fixed part wall 22, respectively, and the wall of the separating layer 19 encompassed by the fixed part wall 22, wherein, as can in particular be seen from FIG. 17, a notch 67, which interrupts a circumferential thread 66 of the separating layer 19 in the axial direction, can further be provided on the outer side of the wall of the separating layer in order to define the discharge path 65.

[0180] Assigned to the front face 64 of the separating layer 19, this notch 67 can additionally transition into a radial recess 68, which can result in a recess-like clearance for a partial region 61 of the sealing element 54 in the use position (see in particular FIGS. 14 and 15). The contact surface at one of the parts T.sub.1 or T.sub.2, respectively, here the separating layer 19, can also be interrupted accordingly in the circumferential direction here.

[0181] In response to a provided overpressure of the hydraulic medium 15, a discharge of hydraulic medium 15, in particular an incremental discharge of hydraulic medium 15, is also made possible from the inside to the outside in this region by opening the relief valve 52. Under elastic deformation of the partial region 61, the partial region 61 of the sealing element 54 can thereby be pushed by the sealing seat against the front face 64 of the separating layer 19, and can be displaced against the rising groove base 63 along the inclined surface 70 essentially in the axial direction, more preferably in the plane B to the outside and overlapped thereto perpendicular to the plane B, whereby the discharge path 65 can essentially open radially to the outside.

[0182] With pressure drop, the partial region 61 of the sealing element 54 can automatically move back into the sealing position, wherein an ingress of, for example, water, from the outside to the inside is counteracted in this position. A pressure acting from the outside in particular on the partial region 61 of the sealing element 54 can have a seal-intensifying effect due to the inclined alignment of the groove base 63.

[0183] According to the exemplary embodiment of the illustration in FIG. 19, a separate drive unit 49 can also be provided, by means of which hydraulic pressure can be generated in this exemplary embodiment, and hydraulic medium can be guided through a connected hydraulic hose 50 to the working head 4, which is connected to the other end of the hydraulic hose 50 in this embodiment. As do the above-described exemplary embodiments, this working head 4 has a hydraulic piston 12 and a hydraulic cylinder 13. In this respect, the working head 4 corresponds to the above-described working heads, further in particular with respect to the electrically insulated formation in the insulation plane E. The work process also applies here in the same way.

[0184] In addition, in particular assigned to the working head 4, the hydraulic hose 50 essentially forms the hydraulic line 16. The hydraulic hose 50 as a whole can have an electrically insulated casing hereby, or the hose jacket as a whole is formed in an electrically insulating manner, respectively.

[0185] Even only in a working head-side end region, assigned to the connection to the hydraulic cylinder 13 on the wall side, the hydraulic hose 50, however, can also consist of an electrically insulating material, over a length, which ensures an optionally required flashover resistance of at least 10 kV/cm.

[0186] As suggested in FIG. 10, a hydraulic hose 50 of this type can also be part of an exclusively handheld, compact working device 1, for example according to FIG. 1, for the formation of the hydraulic line 16 between the hydraulic medium pump 8 in the handle region 3 and the hydraulic cylinder 13.

[0187] The hydraulic hose 50 can be connected directly to the working head-side hydraulic cylinder 13, wherein the corresponding end of the hydraulic hose 50 can be guided through the separating layer 19 according to the hydraulic line sections of the above-described embodiments. According to the above-described hydraulic line section, the insulated hose section can thus contribute to the formation of the insulation plane E (see, for example, FIG. 10).

[0188] The hydraulic hose 50 can also be connected to a hydraulic line section, which is provided in the working head 4 and which is preferably embodied in an electrically insulated manner on the wall side.

[0189] In schematic illustration, FIG. 20 shows a working device 1, in particular a manual working device, more preferably a hydraulically actuated working device, as it is described on the basis of FIGS. 1 to 19, having a sensor 40 for detecting an electrical voltage S.

[0190] The sensor 40 can be arranged in the working region, for example in the region of the working head 4, preferably for the contact-free detection of a voltage, in particular high voltage, in a region around the working head 4. For example, a detection can thereby already take place at a distance of a few centimeters, up to, for example, 50 or 100 cm, optionally also beyond that.

[0191] The working device 1 can be provided with a light signal 41, in the alternative to or in combination therewith also with a sound signal, which signal notifies the user that a voltage S was detected by the sensor 40 in the immediate working region, in particular in the region of the working head 4. In the case of a working device 1, in which in particular the working head 4 is electrically insulated from the drive device part 2, for example according to the above-described embodiments, the work can be performed under voltage. The light signal 41 is to notify the user only of the actual state in this case.

[0192] In the case of manual working devices, which do not have an electrical insulation, in particular no insulation, which is sufficient for the high-voltage range, the signal 41 can lead to the cancellation of the work, which is to be performed.

[0193] The sensor 40 on the device side is in contact with a transmitter 42. The latter can be arranged directly in the working device 1.

[0194] A radio connection F can be established via the transmitter 42, for example via Bluetooth or WLAN, optionally via a mobile radio network.

[0195] The radio connection F makes it possible for the working device 1 to transmit a corresponding detection of a voltage S to a receiver 43. This receiver 43 is provided outside of the working device 1, it can be, for example, a central data processing device or, for example, a notebook or the like, or also a further working device 1, as illustrated. For example, the detection of voltage S can thus further be transferred within a certain working region as warning to further working devices 1 or to the users operating these further working devices 1, respectively.

TABLE-US-00001 List of Reference Numerals 1 working device 28 element 2 drive device part 29 cylinder part 3 handle region 30 cylinder part 4 working head 31 radial widening 5 return valve 32 collar 6 tank 33 base 7 pump tappet 34 opening 8 hydraulic medium pump 35 hydraulic cylinder base 9 electric motor 36 piston head 10 accumulator 37 housing section 11 actuating button 38 hydraulic cylinder wall 12 hydraulic piston 39 section 13 hydraulic cylinder 40 sensor 14 restoring spring 41 light signal 15 hydraulic medium 42 transmitter 16 hydraulic line 43 receiver 17 neck 44 section 18 wall 45 cutting jaw 19 separating layer 46 pressing jaw 20 radial collar 47 wall section 21 fixed part 48 tapering region 22 fixed part wall 49 drive unit 23 receptacle 50 hydraulic hose 24 continuing part 51 seal 25 metallic section 52 relief valve 26 lining part 53 joining region 27 radial widening 54 sealing element 54 sealing element a distance dimension 55 pot wall e level of extension 56 groove v level of protrusion 57 recess x axis 58 sealing seat 59 cutout 60 path A assembly 61 partial region B plane 62 discharge path E insulation plane 63 groove base F radio connection 64 front face S voltage 65 discharge path T.sub.1 part 66 thread T.sub.2 part 67 notch 68 radial recess 69 intermediate space angle 70 inclined surface