in the following description , the same reference numerals are used for the same and similarly working parts . fig1 a depicts a front elevation as a cross - section of an electrode arrangement during a coagulation phase in a first embodiment . represented here are two opposite electrode parts 18 , 19 , wherein one electrode part 18 has a cutting section or a cutting portion 18 a and an insulating section or an insulating portion 21 configured as a distance element . in this embodiment , the distance element forms a device 20 for preventing a short circuit . treated tissue 30 is clamped between the electrodes . the insulating section 21 prevents an unwanted short circuit between the electrode parts 18 , 19 when the branches 11 , 12 are brought together and may be configured as both linear in shape and punctiform . the distance element that is linear in shape will then extend , for example , in the direction of the branch progression , concentrically arranged on the electrode part , over the entire electrode part and accordingly form an edge . advantageously , the steady formation of an arc is thus made possible and an even cut is guaranteed . a punctiform distance element is easy to manufacture , reliably prevents a short circuit occurring between the electrode parts and , as a result of thermal conduction , also guarantees safe coagulation at the point of contact between tissue and distance element . several punctiform distance elements arranged on the corresponding electrode part , e . g . at the respective ends of the electrode part , reliably prevent a short circuit and affect neither the coagulating nor the cutting procedure . the cutting section 18 a is in any event configured as linear in shape . besides preventing a short circuit , the section 21 defines a thickness of the tissue 30 that remains after the coagulation phase , because it prevents an arc forming prematurely with any pre - set coagulating voltage due to too small a space between the electrode parts 18 , 19 . fig1 b depicts the electrode arrangement according to fig1 a , although here the end of the coagulation is represented . according to fig1 a and 1 b a coagulating current flows over an entire surface of the electrode parts 18 , 18 a , 19 , with the effect that the interposed tissue 30 is coagulated . as a result of thermal conduction the tissue 30 is coagulated under the insulating section 21 . fig1 c depicts the electrode arrangement described above during a cutting phase . at the end of the coagulation phase , a hf voltage required for the electrosurgical treatment is slightly increased , with the result that between the cutting section 18 a and the opposite electrode part 19 the arc 23 is formed , which now cuts through the already coagulated tissue 30 . the cutting section 18 a is preferably arranged on the electrode part 18 as an area that tapers in relation to the electrode part 18 and protrudes from this . the electrode part 18 will then consist of an explicit coagulating section beside the cutting section 18 a . the electrode part 18 forming the coagulating section and the cutting section 18 a may , during a coagulating procedure , operate as a coagulating electrode over its entire surface area , i . e . both over the surface area of the coagulating section and over the surface area of the cutting section 18 a , whereas the tapered cutting section 18 a is available solely for a subsequent cutting procedure . the height of the insulating section 21 and thus the space from the cutting section 18 a and opposite electrode part 19 and the hf voltage required for cutting are adjusted to each other . the formation of the arc 23 outside the cutting section 18 a , that is , on the remaining areas of the electrode part 18 , is thus avoided . because of the electrode arrangement just described , one and the same instrument can be used to both coagulate and cut , and a change of instrument can be avoided to the benefit of an uninterrupted operation . in fig2 a front elevation as a cross - section of an electrode arrangement is represented in a second embodiment . tissue clamped between the electrode parts during a treatment is not represented in this embodiment for the benefit of better clarity . the same applies , moreover , to fig3 to 6 . the arrangement differs from the one represented in fig1 a to 1 c in that a cutting section 18 a is configured as an edge with a triangular cross - section . because of the successive transition from one large surface area of the electrode part 18 to its edge - shaped tapering , this embodiment is especially suited to using the entire electrode part 18 as a coagulating electrode where there is sufficient tissue thickness , because the entire surface area and the tissue can be brought into contact with each other . with a suitable hf voltage , an arc 23 is formed between the cutting section 18 a and an opposed electrode part 19 . the insulating section 21 has in this instance a tapered shape to also facilitate mechanical cutting where necessary , that is , the distance element has an explicit cutting edge 22 . with appropriate exertion on the part of the surgeon , the tissue can then be cut through completely following a coagulating procedure and without having to change instrument . this makes for an especially gentle treatment of the tissue without the use of an arc . fig3 depicts a front elevation as a cross - section of an electrode arrangement in a third embodiment . here both a cutting section 18 a is configured on an electrode part 18 and a cutting section 19 a is configured on an electrode part 19 . an insulating section 21 is arranged directly below the cutting section 18 a and symmetrically to the cutting sections 18 a , 19 a . a symmetric arrangement of the cooperating sections 18 a , 21 , 19 a guarantees a uniformly developing arc 23 on peripheral areas of the insulating section 21 , making for an even cutting progression . the insulating section 21 functioning as a distance element is smaller than the cutting sections 18 a , 19 a , so as not to prevent the arc 23 from forming . because of the narrow cutting sections 18 a , 19 a accommodated on the electrode parts 18 , 19 , the cutting progression can be extremely precisely defined . an extremely simple embodiment of an electrode arrangement is depicted in fig4 . here an electrode part 19 only has one cutting section 19 a , whereas on an electrode part 18 facing the electrode part 19 there is only an insulating section 21 configured . because the arc 23 forms in the direction of the cutting section 19 a , this embodiment allows an exact cutting line to be defined in an especially easy way . fig5 depicts a front elevation as a cross - section of an electrode arrangement where an electrode part 18 has an insulating section 21 configured within the electrode part 18 , wherein the insulating section 21 terminates flush with an electrode surface 18 b . a second cutting section 19 a is provided as a distance element on an opposing electrode part 19 . the insulating section 21 and the cutting section 19 a operate in this embodiment as a device 20 for preventing a short circuit . advantageously , a precise cut is also provided for here since the arc 23 is formed between the incorporated section 21 and the cutting section 19 a . the insulating section 21 with this embodiment is protected from jolts or similar mechanical strains and essentially from the arc 23 also . fig6 depicts a similar configuration of an electrode arrangement as represented in fig5 . an insulating section 21 is configured here , however , to be sunk in a corresponding electrode part 18 , so that a recess 18 c is formed on the electrode part 18 . a cutting section 19 a configured on an opposing electrode part 19 can be at least partially lowered into the recess 18 c , so that an arc 23 can form inside the recess 18 c toward the cutting section 19 a during the cutting procedure . surrounding tissue is thus protected from burning , while at the same time a precise cutting line can be defined . in this embodiment , too , the cutting section 19 a may be configured with an explicit cutting edge , allowing the tissue to be cut through mechanically . fig7 depicts a fully illustrated electrosurgical instrument 10 with an electrode arrangement according to the invention . in the illustration the reference numerals 11 and 12 identify two branches of the electrosurgical instrument 10 . these branches 11 , 12 have ends 13 , 14 fitted with electrode parts 18 , 19 , wherein the electrode parts 18 , 19 face each other . with the aid of the electrode parts 18 , 19 , it is possible to grasp a vessel , for example , and to coagulate or cut this by supplying a high - frequency current . in addition , gripping parts 11 a , 12 a are provided which are attached to respective proximal ends 15 , 16 of the branches 11 , 12 . the proximal ends 15 , 16 of the squeezing parts 11 , 12 end in a connecting element 17 a of current - supplying devices 17 . the current - supplying devices 17 serve to connect the electrosurgical instrument 10 to a hf generator ( not represented ), which produces a hf voltage , so that a hf current may be supplied to the electrode parts 18 , 19 by , for example , electrical leads ( not depicted ) running through the instrument 10 . an edge - shaped cutting section 18 a is configured on the electrode part 18 . this has two insulating sections 21 , 21 ′ configured as two punctiform distance elements . the distance elements arranged at the respective ends of the electrode part 18 or on the cutting section 18 a reliably prevent a short circuit and affect neither the coagulating nor the cutting procedure . to achieve a high degree of resistance of the insulating section to an arc , the section is preferably constructed from material that is resistant to arc erosion . a high degree of resistance to abrasion is provided in particular by the use of ceramic materials .
the invention concerns an electrosurgical instrument comprising two articulated branches , which can be actuated in the manner of a squeezing tool . the instrument further comprises electrode parts at the distal ends of the branches for grasping tissue and for conducting a coagulating current through the tissue in order to cause it to coagulate as well as current - supplying devices for supplying the coagulating current to the electrode parts from an hf generator . at least one device for preventing a short circuit is arranged and configured on the electrode parts in such a way that the electrode parts are unable to touch .