DE20207785U1 - Surgical cutter, has cavities in opposing cutting edges forming locating cavity for object being cut - Google Patents

Abstract

The cutting edges (12, 13) contain opposing cavities (12', 13') which combine to form a single locating cavity for the object being cut when the cutting levers (23, 24) are initially closed. As the levers approach the end closed position, these cavities become pressed increasingly tighter against the object until the latter is cut into two pieces.

Description

Geomed G5141-S/ga

Surgical forceps

The invention relates to a forceps, in particular a surgical forceps according to the preamble of claim 1.

A generic surgical cutting forceps is known, for example, from EP 0 321 884 Bl. It is used to cut through elongated objects, e.g. wires or screws, which are used in surgical operations.

Recently, wire ropes made up of many individual strands have been increasingly used in surgery. These have a relatively small diameter of up to 2 mm and must be cut perfectly. Wire ropes are a new type of implant that is ideal for the safe treatment of some bone fractures, joint fractures and for relieving pressure during ligament sutures. The broad range of indications in question is generally referred to as rope osteosynthesis.

The advantage of wire ropes over rigid round wires is that they are easier to handle and have significantly better mechanical properties. The flexible ropes can be tensioned very easily, which means that the osteosynthesis principle of tension banding can be implemented in every single case.

Usually, a rope is cut with conventional cutting pliers, but the cutting geometry causes the individual strands of the rope to spring open, which poses a significant risk of injury to both patient and doctor. As a rule, not all strands are cut in the first cut, which makes it necessary to cut again or even several times. This can result in small pieces of cutting waste in the area of the operating field.

The previously known cutting pliers also have the disadvantage that with frequent use and multiple cutting of wire ropes, the cutting function deteriorates relatively quickly due to the cutting geometry. Individual strands are then no longer cut through, but are clamped or squashed between the cutting surfaces.

The main aim of the present invention is to create cutting pliers, in particular surgical pliers, which allow safe, waste-free cutting of wire ropes with common rope diameters down to 2 mm. All strands should be cut safely, regardless of the rope diameter and the number of strands. The cutting surface should be smooth and the twisted rope should not spring open at the cutting point. The round rope cross-section in particular should be retained at the cutting edge.

Furthermore, the invention is intended to increase the service life and cutting ability of the cutting edges or cutting inserts.

To solve these problems, the features of the characterising part of claim 1 are provided.

Due to the design according to the invention, the object to be cut is surrounded on all sides by the cutting edges before it is severed, thereby preventing radial deflection of individual strands or groups of strands.

Advantageous designs of the cutting edges or recesses can be found in claims 2 and 3.

The embodiment according to claim 4 is particularly preferred because it ensures perfect guidance of the cutting levers carrying the cutting edges during the cutting process. The guide planes are designed according to claim 5 such that one cutting lever or cutting lever inserts attached to it engage in the other cutting lever or cutting lever insert like a drawer, which ensures perfect guidance in the two opposite directions perpendicular to the cutting direction.

According to claims 6 to 13, it is ensured that the object to be cut, i.e. in particular the wire rope to be cut, is supported on both sides of the cutting edges on the cutting levers or cutting lever inserts in such a way that during a cutting process the cutting force is evenly transferred to the object not only in the area of the cutting edge, but also in an adjacent material area.

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The advantage of a uniform support of the parts of the object to be cut that are to be sheared off from one another is also achieved by the embodiments according to claims 14 to 18.

The invention is particularly advantageously used in pliers in which the cutting levers have cutting lever inserts according to claim 19.

The movement mechanism of the pliers according to the invention should preferably be designed according to claims 20 or 21.

The invention of the following figures is written for example based on the drawing; in this shows

Fig. 1 is a partially sectioned side view of an inventive

surgical forceps in open position,

Fig. 2 is a plan view of the object of Fig. 1 in the direction of the

Arrow II in Fig. 1 with a cutting break in the mouth or working area, whereby the upper cutting lever and the upper

Cutting insert is omitted to reveal a top view of the lower cutting insert,

Fig. 3 is an enlarged view of the front end area of the

Fig. 1 shown surgical forceps, wherein also the

dividing wire rope is shown,

Fig. 4 is a schematic front sectional view of an object

clamping cutting lever inserts in cutting and axial direction in the area of the cutting edges in an enlarged scale compared to Fig. 3,
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Fig. 5 is an enlarged, schematic, perspective view of the

object of Fig. 4, seen in the direction of arrow V in Fig. 2 and

Fig. 6 is an enlarged, schematic, perspective view of the

Object of Fig. 4, seen in the direction of arrow VI in Fig. 2.

When in the following description reference is made to "above" or "below", reference is made to the pliers position according to Figures 1, 3 to 6. Of course, the pliers shown in these figures can be held in any position during use.

According to Figures 1, 2, the surgical forceps according to the invention has two handle levers 17, 18 which are connected to one another via a joint 14 and are pressed apart by a spring arrangement 15. The front end of the lower handle lever 17 merges in one piece into a lower cutting lever 23 which is connected in an articulated manner to an upper cutting lever 24 by means of a joint 16. 25

Beyond the joint 14 of the handle lever 18, a relatively short lever is provided, which is connected in an articulated manner via a first toggle lever joint 20 to a lever tab 21 which is angled approximately in relation to the toggle lever 19.

In the area facing away from the first toggle lever joint 21, a second toggle lever joint 22 is provided, which creates an articulated connection between the toggle lever bracket 21 and the upper cutting lever 24. In this way, such a variable force transmission is realized that the cutting force is significantly increased as the cutting levers 23, 24 approach each other, as is described in detail in EP 321 Bl.

At the front end of the cutting levers 23, 24, cutting inserts 23' and 24' are fastened by means of screws 34, which, according to Figs. 1 to 6, have recesses 12' and 13' facing one another, which are surrounded by essentially semicircular cutting edges 12, 13.

The diameter of the recesses 12', 13' corresponds essentially to the diameter of the wire rope 11 to be severed, which is shown in Fig. 3, 4.

In order to ensure that the two cutting inserts 23', 24' are guided properly during the cutting process, the cutting insert 24' according to Fig. 4 has a projection 30 with a substantially rectangular cross-section, which is opposite a correspondingly shaped recess 31 in the lower cutting lever insert 23'. Primary guide planes 25 and 26 are provided at the right ends of the projection 30 and the recess 31 in Fig. 4, at the end of which the rounded cutting edges 12, 13 are located. On the side of the projection 30 or the recess 31 facing away from the primary guide planes 25, 26, a first secondary guide plane 27 is provided at the end of the recess 31 and a second secondary guide plane 28 is provided at the projection 30.

A guide plane 28 is formed which cooperates with the first secondary guide plane 27 for guidance. In this way, the projection 30 moves like a drawer into the recess 31 during the cutting process, with the guide planes 25, 26, 27, 28 ensuring perfect lateral guidance of the two cutting levers 23, 24 or the cutting lever inserts 23', 24'.

The recesses 12', 13', which are surrounded by the cutting edges 12, 13, continue in the projections 30 and 32, respectively, so that bearing channels 12" and 13" are formed there, which serve to accommodate the wire rope 11 (Figure 4). The projection 32 adjoins the primary guide plane 25 to the right in Figures 4 to 6. In this way, the wire rope 11 is perfectly and evenly supported radially on both sides of the cutting edges 12, 13.

In order to ensure that only the cutting edges 12, 13 have a cutting effect on the wire rope 11, it is ensured that the edge 29 at the lower end of the secondary guide plane 28 is not opposite a corresponding cutting edge on the lower cutting lever insert 23', so that there is no cutting effect in this area.

According to Fig. 4, when cutting, the projection 30 penetrates into the recess 31, shearing off the part 11" of the wire rope 11, whereby the sheared off part 11 also finds space in the recess 31 and is not stressed in this area. Above the part 11", next to the projection 30, a recess 33 is provided, which creates sufficient space when the cutting insert 24' descends so that the sheared off part 11"

sheared wire rope part H" is not impacted by the material of the cutting insert 24'.

The mode of action of the described surgical forceps is as follows: 5

In the open state shown in Fig. 1 and 3 to 6, the wire rope to be severed is inserted according to Fig. 3, 4 in such a way that it comes to lie, for example, in the lower recess 12' and in the adjoining groove-like bearing channel 12" in the projection 32.

The two handle levers 17, 18, which are held by hand, are then pressed together, whereby the cutting levers 23, 24 or the cutting lever inserts 23', 24' approach each other. The upper cutting edge 13 approaches the upper part of the circumference of the wire rope 11 until the cutting edge 13 touches the circumference of the wire rope 11. At this moment, the two bowl-shaped recesses 12', 13' complement each other to form a single passage opening surrounding the wire rope 11. In addition, at this moment at the latest, the primary guide planes 25, 26 and the secondary guide planes 27, 28 come into contact with each other in a guide system, so that from this moment on, the two cutting levers 23, 24 or cutting lever inserts 23', 24' can no longer move laterally relative to each other.

As the cutting levers 23, 24 approach further, the cutting edges 12, 13 penetrate into the material of the wire rope 11 and shear the two parts 11', 11" (Fig. 4) apart from each other. During this shearing process, the circumference of the parts 11', 11" is supported in the groove-like bearing channels 12", 13" on the projections 32 and 30 in such a way that the force transfer

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transfer to the circumference of the wire rope 11 does not lead to bending or distortion of the wire rope in the cutting area. The perfect, relative guidance of the cutting inserts 23', 24' relative to one another also makes a significant contribution to this.
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During the cutting process, the total passage opening formed by the recess 12', 13' decreases until it becomes smaller and smaller and finally disappears, which corresponds to the separation of the two parts 11', 11" (Fig. 4) from each other.

During this cutting process, the parts of the wire rope 11 that are not in contact with the cutting edges 12, 13 or the groove-like bearing channels 12", 13" on the projections 32, have no contact with the cutting lever inserts 23', 24', so that the wire ends are not subjected to an extent that could cause damage during and after cutting. This creates a smooth, clean cutting surface on the two parts 11', 11", and the spraying away of strand parts is prevented.

The invention enables safe cutting of common rope diameters down to 2 mm. A smooth cutting surface is created and the twisted wire rope cannot spring open at the cutting point due to the positive shearing according to the invention. The round rope cross-section is largely retained at the cutting edge.

The service life and cutting ability of the tool are significantly increased by the integrated guide of the cutting inserts.

It is not possible to trim the cutting edges as with a conventional scissor cut.

Shearing with the cutting pliers according to the invention prevents severed rope pieces (strands) from spraying away, since no lateral forces occur due to the wedge effect.

Particularly important is the cutting geometry according to the invention with the 90° angle between the primary guide planes 25, 26 and the bearing channels 12" or 13" on the projections 30, 32, as can be seen in particular from Fig. 4. Compared to the conventional shearing principle with an acute wedge angle, this increases the service life of the cutting edges.

According to the invention, the cutting lever inserts are made of high-quality, special stainless steel with high hardness.

Since the cutting lever inserts are easily replaceable and are always available as a spare parts set, a high level of cost-effectiveness is ensured.

Manufacturing tolerances that could affect the cutting function when changing the cutting inserts are compensated for by the guide levels 25 to 28 integrated in the cutting lever inserts themselves. 25

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List of reference symbols

11 Wire rope

1 &Ggr; sheared part of the wire rope

11" sheared part of the wire rope

12 (lower) cutting edge 12' (lower) recess 12" (lower) bearing channel

13 (upper) cutting edge

13' (upper) recess

13" (upper) bearing channel

14 Joint

15 Spring arrangement 16 Joint

17 (lower) handle lever

18 (upper) handle lever

19 Knee lever

20 first toggle joint 21 toggle bracket

22 second knee lever joint

23 (lower) cutting lever

23' (lower) cutting lever insert

24 (upper) cutting lever

24' (upper) cutting lever insert

25 (lower) primary management level

26 (upper) primary management level

27 (lower) secondary management level

12

28 (upper) secondary management level

29 (lower) edge of the (upper) secondary guide level

30 lead

31 Recess 32 Projection

33 Recess

34 screws

35 screws

36 Head Start 10

Claims (21)

1. Pliers, in particular surgical pliers for cutting wires, screws or the like, in particular wire ropes ( 11 ), with two cutting levers ( 23 , 24 ) connected by a joint ( 16 ) and having cutting edges ( 12 , 13 ) which cooperate with one another at the front end, which are acted upon by handle levers ( 17 , 18 ) arranged on the side of the joint ( 16 ) facing away from the cutting edges ( 12 , 13 ), the cutting edges ( 12 , 13 ) being provided at the end of primary guide planes ( 25 , 26 ) which extend at least substantially in the cutting direction and slide on one another, characterized in that the cutting edges ( 12 , 13 ) form the edge of recesses (23, 24) which are opposite one another when the cutting levers ( 23 , 24 ) are in the open state. 12 ', 13 ') which, when the cutting levers ( 23 , 24 ) are closed, initially combine to form a passage opening for the object ( 11 ) to be cut, which passage opening is surrounded on all sides by parts of the cutting edges ( 12 , 13 ), which becomes increasingly smaller as the closing process continues and finally disappears, the object ( 11 ) to be cut being divided into two parts ( 11 ', 11 "). 2. Pliers according to claim 1, characterized in that the cutting edges ( 12 , 13 ) are rounded in the region of the recesses ( 12 ', 13 '). 3. Pliers according to claim 2, characterized in that the recesses ( 12 ', 13 ') are at least approximately semicircular. 4. Pliers according to one of the preceding claims, characterized in that secondary guide planes ( 27 , 28 ) sliding on one another are also provided on both cutting levers ( 23 , 24 ) at a distance from the primary guide planes ( 25 , 26) in the direction of the axis of the joint ( 16 ), which secondary guide planes (27, 28 ) form a linear guide with the primary guide planes ( 25 , 26 ) preventing a relative movement in the two opposite directions of the axis of the joint ( 16 ), wherein of the edges of the secondary guide planes ( 27 , 28 ) facing the object ( 11 ) to be cut, at most one ( 29 ) touches the object ( 11 ) during the closing process. 5. Pliers according to claim 4, characterized in that the guide planes ( 26 , 28 ) provided on the same cutting levers ( 23 , 24 ) are opposite to the guide planes ( 25 , 27 ) provided on the other cutting part ( 24 , 23 ). 6. Pliers according to claim 4 or 5, characterized in that between two guide planes ( 26 , 28 ) provided on the same cutting lever ( 24 ), a projection ( 30 ) is provided on the cutting lever ( 24 ), partially enclosing the object and laterally delimited by the guide planes ( 26 , 28 ). 7. Pliers according to claim 6, characterized in that between the two guide planes ( 25 , 27 ) on the other cutting lever ( 23 ) there is provided a free space ( 31 ) of such an extent in the cutting direction that the part ( 11 ') of the object ( 11 ) sheared off by the projection ( 30 ) can be received therein. 8. Pliers according to claim 6 or 7, characterized in that the cross sections of the projection ( 30 ) containing the cutting and axial directions are rectangular. 9. Pliers according to claim 8, characterized in that the free space ( 31 ) is correspondingly rectangular. 10. Pliers according to one of claims 6 to 9, characterized in that the recess ( 13 ') in the cutting edge ( 13 ) provided on the projection ( 30 ) continues in the axial direction along the entire projection ( 30 ), so that a storage channel ( 12 ") open on one side is formed for the object ( 11 ). 11. Pliers according to one of claims 7 to 10, characterized in that the primary guide plane ( 26 ) provided laterally of the recess ( 31 ) and having the cutting edge ( 13 ) is formed on a projection ( 32 ) facing the object. 12. Pliers according to claim 11, characterized in that the recess ( 12 ') provided on the cutting edge ( 12 ) continues into a correspondingly shaped bearing channel ( 12 ") open on one side provided in the projection ( 32 ). 13. Pliers according to claim 11 or 12, characterized in that opposite the projection ( 32 ) on the other cutting lever ( 24 ) there is provided a recess ( 33 ) of such an extent in the cutting direction that the part ( 11 ") of the object ( 11 ) sheared off by the projection ( 32 ) can be received therein. 14. Pliers according to one of the preceding claims, characterized in that the secondary guide plane ( 27 ) having no cutting edge is formed on a projection ( 36 ). 15. Pliers according to one of the preceding claims, characterized in that the projections ( 30 , 32 ) which are designed to bear against the parts ( 11 ', 11 ") of the object to be cut ( 11 ) to be sheared off from one another extend from the two primary guide planes ( 25 , 26 ) in opposite directions. 16. Pliers according to claim 14, characterized in that the projections ( 30 , 32 ) perpendicular to the pivot axis have at least substantially cross-sections corresponding to the associated guide planes ( 25 , 26 ). 17. Pliers according to claim 15 or 16, characterized in that the length of the projections ( 30 , 31 ) in the axial direction is at least equal to the diameter of the object to be cut ( 11 ). 18. Pliers according to claim 17, characterized in that at least one ( 30 ) of the projections ( 30 , 32 ) has a significantly larger extension in the axial direction than the diameter of the object to be cut ( 11 ). 19. Pliers according to one of the preceding claims, characterized in that the cutting edges ( 12 , 13 ), the guide planes ( 25 , 26 ; 27 , 28 ) and/or the projections ( 30 , 32 , 36 ) are provided on cutting lever inserts ( 23 ', 24 ') forming part of the cutting levers ( 23 , 24 ). 20. Pliers according to one of the preceding claims, characterized in that the one handle lever ( 17 ) is connected directly and preferably in one piece to a cutting lever ( 23 ) and the other handle lever ( 18 ) is articulated ( 14 ) on the first handle lever ( 17 ) or on the first cutting lever ( 23 ) and acts on the other cutting lever ( 24 ) via a gear ( 18 to 22 ). 21. Pliers according to claim 20, characterized in that the cutting levers ( 23 , 24 ) are connected to the handle levers ( 17 , 18 ) according to EP 321 884 B1.