EP0515830A1 - Scissors - Google Patents

Abstract

In the case of scissors, in particular hairdressing scissors, with an articulated connection consisting of an articulated screw (1) and a screw nut (18), the articulated screw (1) being essentially non-rotatably connected to a pair of scissors (21), play is prevented between the articulated screw (1) and one scissor half (21) that the screw nut (18) has on its inner wall an annular groove (10) in which an annular body made of flexible material (11) is arranged, the inner diameter of which is smaller than the thread diameter the articulated screw (1), and that the screw nut (18) also has on its inner end face a flexible molded part (22) which, under pressure, on the screw nut (18) and the wall of the bore (20) of one scissor half (21) is present. <IMAGE>

Description

The invention relates to scissors, in particular hairdressing scissors, with an articulated connection consisting of an articulated screw and a screw nut, the articulated screw being essentially non-rotatably connected to a pair of scissors and the screw nut on the circumference of a neck attachment which engages in a circular recess in the bore of one scissor half , or has on its end facing the bore a flexible body which rests under pressure on the screw nut and the wall of the bore.

Such scissors are known from DE-PS 30 23 057. With this pair of scissors, the steel screw nut of the joint connection has an annular groove on the circumference of its neck attachment, into which a flexible O-ring is inserted. The O-ring lies under pressure on the neck of the screw nut and the wall of the bore in one half of the scissors. As a result of the pressure exerted on the neck of the screw nut by the O-ring, the screw nut should be prevented from twisting. The contact pressure is selected so that the movement of the scissors can be finely regulated by turning the screw nut.

The hinge screw of the scissors known from the mentioned publication has two opposite milled surfaces on its shank and engages through a correspondingly designed opening in one half of the scissors, the upper part, so that it is connected to the upper part of the scissors essentially non-rotatably.

When mass-producing such scissors, however, the non-rotatability of the connection between the hinge screw and Oberbeck cannot be achieved completely. This connection therefore has a certain amount of play due to the manufacturing process. Since the screw nut rests against rotation in the Oberbeck of the scissors due to the O-ring arranged on the neck, this play creates a play in movement between the screw nut and the joint screw.

The play of movement between the nut and the hinge screw is particularly disruptive when cutting with precision scissors of the type mentioned at the beginning. Today's precision scissors have a closing pressure of approx. 30 g, which is set electronically. Due to the very low closing pressure, the play between the shaft of the hinge screw and the opening in the Oberbeck or the nut and the hinge screw is noticeable through impact. These noticeable blows are felt by the person operating the scissors, e.g. the hairdresser found it uncomfortable. In addition, the joint screw is subject to greater wear due to the impacts. It should be noted that the scissors are operated about a thousand times in a normal haircut.

The invention has for its object to provide a pair of scissors of the type mentioned, in which the above-mentioned play in the shaft of the hinge screw and the opening in the upper bowl or the nut and the hinge screw prevented and thus the previously when cutting with precision scissors noticeable blows can be excluded.

This object is achieved in that the nut has on its inner wall an annular groove in which an annular body made of flexible material is arranged, the inner diameter of which is smaller than the thread diameter of the joint screw.

Because of the measures according to the invention, the screw nut contacts the shaft of the joint screw while exerting a pressing pressure. On the other hand, since the screw nut lies non-rotatably on the Oberbeck scissors, play between the joint screw and the Oberbeck is avoided. Therefore, even with precision scissors with an extremely low closing pressure, there are no more shocks during cutting. The inner diameter of the annular body resting on the shaft of the joint screw is preferably selected to be smaller than the core diameter of the thread of the joint screw. This dimensioning achieves a higher pressure between the nut and the hinge screw.

In a further development of the invention, the annular groove is arranged on the end region of the screw nut opposite the bore in the half of the scissors. The screw nut preferably has a blind hole on its end face opposite the bore in the half of the scissors, the diameter of which is larger than the thread diameter of the joint screw and in which the annular groove is arranged.

The annular groove can expediently be arranged on the end of the blind hole facing away from the end face of the screw nut.

In order to make it easy to twist the screw nut to regulate the movement of the scissors, a groove has so far been formed in the face of the screw nut. The nut can be actuated by inserting a tool into this groove. Such a groove is not suitable for the scissors according to the invention if the annular groove is arranged in the front end region of the inner wall of the screw nut.

As a further development of the screw nut based on the invention, a knurled nut is therefore preferably provided.

On the other hand, the screw nut according to the invention can also be used as a polygonal nut, e.g. be designed as a hexagon nut. This design also has the advantage that the diameter of the nut can be made relatively small. A key to operate the nut can be supplied with the scissors.

In the scissors according to the invention, as described in DE-PS 30 23 057, the screw nut can have a neck extension, on the circumference or end face of which an annular groove is arranged, in which a flexible body in the form of an O-ring is mounted.

In another preferred embodiment, the flexible body which bears against the nut and the wall of the bore in one half of the scissors is designed as a molded part, the outside of the bore and the inside of which is adapted to the diameter of the hinge screw and which has an end face on the one facing the bore The face of the nut is pressed under pressure. The pressure is achieved by tightening the hinge screw or the nut.

Because of this pressure, the flexible molded part also exerts a radial force on the shaft of the hinge screw, so that the pressure under which the screw nut rests against the shaft, and thus the effect of the annular flexible body arranged on the inner wall of the screw nut, is further increased.

In a preferred development of this embodiment, the bore of the one pair of scissors has a constriction in its end area facing away from the screw nut and its end area facing the screw nut has an enlargement as a circular recess, the transition area between the two end areas being conical. Due to the taper of the intermediate area, the force component directed towards the shaft of the joint screw is further reinforced when the elastic molded part is pressed together by tightening the joint screw or the nut.

The screw nut expediently has a short neck extension, with which it is guided in the circular recess of the bore or a circular recess of the molded part and compresses the flexible molded part in the bore.

The cross section of the narrowed end region of the bore can correspond to the cross section of the shaft of the joint screw. To produce an anti-rotation device between the hinge screw and the one half of the scissors, the shaft expediently has two opposite flat surfaces which can be milled.

In another preferred embodiment, the inner diameter of the narrowed end region of the bore is larger than the largest outer diameter of the joint screw. In this case it extends flexible molded part in the narrowed end area of the bore. To produce the anti-rotation device between the shaft of the hinge screw and the relevant scissor half, the narrowed end region of the bore has a rectangular punched-out area.

The flexible molded part has the advantage over an annular flexible body arranged on the circumference of the neck of the screw nut that the articulated connection can also be set in a safe manner by a non-specialist. Since the ring-shaped body arranged on the circumference of the neck of the screw nut generates a pressure between the screw nut and the inner wall of the bore in one half of the scissors even with an even looser connection, it is not easy for the non-specialist, in particular when readjusting and reassembling after cleaning the scissors to adjust the articulation correctly. In this case, the joint, which initially appears to be firm, becomes loose after a certain time. On the other hand, the molded part which is adapted to the inner wall of the bore and which is compressed by tightening the articulated connection permits a 100% reliable setting.

Fig. 1

einen Längsschnitt durch eine Schraubenmutter,

Fig. 2

eine Seitenansicht an einer zur Schraubenmutter gemäß Fig. 1 gehörenden Gelenkschraube,

Fig. 3

einen Querschnitt durch den Schaft der Gelenkschraube gemäß Fig. 2,

Fig. 4

einen Längsschnitt durch eine anders gestaltete Schraubenmutter,

Fig. 5

eine stirnseitige Draufsicht auf die Schraubenmutter nach Fig. 4,

Fig. 6

einen Schnitt durch eine andere Ausführung der Gelenkverbindung einer Schere,

Fig. 7

einen Schnitt längs der Linie VII-VII in Fig. 6,

Fig. 8

eine stirnseitige Ansicht des flexiblen Formteils, das in Fig. 6 als Schnitt längs der Linie VI-VI gezeigt ist,

Fig. 9

eine seitliche Ansicht des Formteils nach Fig. 8 in Richtung des Pfeils IX,

Fig. 10

einen Schnitt durch eine andere, einfach gestaltete Gelenkverbindung einer Schere und

Fig. 11

einen Schnitt längs der Linie XI-XI in Fig. 10.

Some preferred embodiments of the invention are described below with reference to the drawing. The drawing shows:

Fig. 1

a longitudinal section through a nut,

Fig. 2

2 shows a side view of a joint screw belonging to the screw nut according to FIG. 1,

Fig. 3

3 shows a cross section through the shaft of the joint screw according to FIG. 2,

Fig. 4

a longitudinal section through a differently designed screw nut,

Fig. 5

4 shows an end view of the screw nut according to FIG. 4,

Fig. 6

a section through another embodiment of the articulated connection of a pair of scissors,

Fig. 7

6 shows a section along the line VII-VII in FIG. 6,

Fig. 8

6 shows an end view of the flexible molded part, which is shown in FIG. 6 as a section along the line VI-VI,

Fig. 9

8 in the direction of arrow IX,

Fig. 10

a section through another, simply designed joint connection of scissors and

Fig. 11

a section along the line XI-XI in Fig. 10th

The articulated connection shown in FIGS. 1 to 5 for a pair of scissors consists of an articulated screw 1 and a screw nut 3 provided with a neck extension 2.

The head 4 of the articulated screw 1 is dome-shaped on the back and lies with this part in a pan-like recess in the lower pelvis of the scissors, which can also be formed by a suitable contact part. The shaft 5 of the joint screw 1 has two parallel flats 6.

The articulated screw 1 engages with the shaft 5 through an opening of the lower pelvis with play and an opening of the upper pelvis with a play that is as small as possible only due to the manufacturing. The opening of the upper pelvis has flats corresponding to the flats 6 of the shaft 5 of the hinge screw 1, with which the shaft 5 cooperates, so that the hinge screw 1 is rotatably connected to the upper bowl except for the aforementioned play.

The nut 3 shown in Fig. 1 is guided on the threaded end of the hinge screw 1. With its neck extension 2, it is supported in a circular recess in the upper pelvis.

The neck extension 2 has on its circumference an annular groove 8, in which an annular body 9 made of flexible material is supported and presses against the neck extension 2 of the screw nut 3 and the wall of the recess in the upper part of the scissors.

As further shown in Fig. 1, the screw nut 3 has an annular groove 10 on its inner wall, in which a further annular body 11 made of flexible material is arranged, the inner diameter of which is smaller than the thread diameter and moreover somewhat smaller than the core of the thread of the joint screw 1. When the screw nut 3 and the joint screw 1 interact, this annular body 11 rests under pressure on the inner wall of the screw nut 3 and the shaft 5 of the joint screw 1.

The screw nut 3 has on its end face opposite the neck extension 2 a blind bore 12, the diameter of which is larger than the thread diameter of the joint screw 1. The annular groove 10 is on the End of the blind bore 12 facing away from the end face of the nut 3. The annular projection 13 of the inner wall on the end face of the screw nut 3 prevents the annular body 11 from falling out.

In order to enable the screw nut 3 to be easily rotated to regulate the movement of the scissors, the screw nut 3 is provided with knurling 14 on its circumference, as shown in FIG. 1.

FIGS. 4 and 5 show a further exemplary embodiment of a screw nut 15 which is provided with a neck extension 7 and is designed as a hexagon nut. The end face of the screw nut 15 merges into a dome-shaped area 16, which is adjoined by an area 17 consisting of six flat side surfaces. Otherwise, the screw nut 15 is designed like the screw nut described in the above exemplary embodiment. In particular, it has a blind bore 12 on its end face, at the end of which there is an annular groove 10 for receiving a flexible, annular body 11.

In the further exemplary embodiment of a pair of scissors shown in FIGS. 6 to 9, the flexible body bearing against the screw nut 18 and the wall 19 of the bore 20 of the one pair of scissors 21 is designed as a molded part 22, the outside of the bore 20 and the inside of the diameter of the articulated screw 1 is adapted and which rests with an end face 23 on the end face of the screw nut 18 facing the bore 20 under pressure. The flexible molded part 22 is produced as a rubber-like, highly elastic injection molded part.

The bore 20 of one scissor half 21 has in its end region 24 facing away from the screw nut 18 a narrowing and in its end region 25 facing the screw nut 18 an expansion as a circular recess, the transition region 26 between the two end regions 24 and 25 being conical. The screw nut 18 has a short neck extension 27 with which it is guided in a circular recess in the molded part 22 and presses the flexible molded part 22 between the wall of the bore 20 and the shaft 5 of the joint screw 1. As a result, a non-positive connection between the nut 18 and the shaft 5 of the joint screw 1 is achieved via the flexible molded part 22. This non-positive connection reinforces the action of the annular flexible body 11 arranged in the annular groove 10 of the screw nut 18.

In this embodiment, an additional radial frictional connection between the neck 27, the nut 18 and the molded part 22 is achieved. On the other hand, it is sufficient to provide the molded part 22 with a flat end face and to form the neck of the nut so that it is guided in the recess in the bore 20.

The end region 24 of the bore 20 facing away from the screw nut 18 is designed in the form of a rectangular punching, as can be seen in FIG. 7. The diameter of this punch is larger than the diameter of the shaft 5 of the joint screw 1, so that the elastic molded part 22 extends between the narrowed end region 24 and the shaft 5 of the joint screw 1. Due to the cross-sectional shape of the shaft 5 and the narrowed end region 24, the joint screw 1 is adequately secured against rotation with respect to the one scissor half 21.

The bore 20 in the scissor half 21 can be carried out in such a way that the scissor half 21 is first provided with a cylinder bore which corresponds approximately to the smallest diameter of the narrowed end region 24. The enlarged end region 25 facing the screw nut 18 is then produced in the form of a circular recess through a corresponding blind hole. The conical transition region 26 is achieved by using a twist drill. In this case, the inclination of this area is predetermined by the twist drill and is preferably 60 ° with respect to the axial direction of the bore 20. The cylindrical bore in the narrowed end area 24 is then expanded to a square cross-sectional shape by punching out.

The flexible molded part 22 is adapted both in the enlarged end region 25 and in the narrowed end region 24 on its outside of the bore 20 of the scissor half 21 and on its inside to the cross section of the shaft 5 of the joint screw 1. The shape of the molded part 22 is shown in more detail in FIGS. 8 and 9. The walls of the molded part corresponding to the regions 24, 25 and 26 of the bore 20 are designated in FIGS. 8 and 9 with 24 ', 25' and 26 '. Due to the square punching of the narrowed end region 24 and the lateral flats of the shaft 5 of the joint screw 1, a sufficient protection against rotation between the joint screw 1 and the scissor half 21 is ensured. The molded part 22 bearing against the pressure in the bore 20 and the shaft 5 further prevents play between the joint screw 1 and the bore 20.

As can be seen from FIG. 6, the other half of the scissors 28, the lower section, is also provided with an identical bore 20. Because the diameter of the narrowed End area 24 is larger than the diameter of the shaft 5 everywhere, the joint screw 1 can rotate relative to the other scissor half 28. The dome-shaped head 4 of the joint screw 1 on its underside is supported by a plastic slide ring 29 in the enlarged end region 25 of the bore 20.

These scissor halves, which are designed identically in the area of the articulated connection, not only lead to a simplification of the storage and a reduction of the manufacturing effort. In addition to the precision connection considered here, they also enable a simpler and inexpensive articulated connection for the same scissor halves 21 and 28. This simple version is shown in FIGS. 10 and 11. The articulated screw 30 is combined with a plastic nut 31 into which the screw cuts the thread during screwing. The screw nut 31 is secured on the shaft 32 by self-locking. Under the screw head 33, the underside of which is dome-shaped, there is a plastic sliding ring 29. Since in this simple version the plastic nut can only be used with a relatively large thread pitch, a fine adjustment, as is the subject of the present invention, is such Mother not possible.

Reference symbol list

1

Joint screw

2nd

Neckline

3rd

Nut

4th

head

5

shaft

6

Flattening

7

Neckline

8th

annular groove

9

annular body

10th

annular groove

11

annular body

12

Blind hole

13

annular projection

14

Knurling

15

Nut

16

dome-shaped area

17th

Hexagon area

18th

Nut

19th

Wall

20th

drilling

21

a pair of scissors

22

Molding

23

Face

24th

End area

24 '

Wall

25th

End area

25 '

Wall

26

Transition area

26 '

Wall

27th

Neckline

28

other half of the scissors

29

Plastic slide ring

30th

Joint screw

31

Nut

32

shaft

33

Screw head

Claims (10)

Scissors, in particular hairdressing scissors, with an articulated connection consisting of an articulated screw (1) and a screw nut (3; 15; 18), the articulated screw (1) being essentially non-rotatably connected to a pair of scissors (21) and the screw nut (3; 15 ; 18) on the circumference of a neck extension (7) which engages in a circular recess in the bore (20) of one pair of scissors (21), or on its end face facing the bore (20), has a flexible body which is pressed against the screw nut (3; 15; 18) and the wall of the bore (20), characterized in that the screw nut (3; 15; 18) has on its inner wall an annular groove (10) in which an annular body made of flexible material (11) is arranged, the inner diameter of which is smaller than the thread diameter of the joint screw (1). Scissors according to claim 1, characterized in that the inner diameter of the annular body (11) is smaller than the core diameter of the thread of the hinge screw (1). Scissors according to claim 1 or 2, characterized in that the screw nut (3; 15; 18) has a blind bore (12) on its end face opposite the bore (20) of one scissor half (21), the diameter of which is larger than the thread diameter of the Articulated screw (1), and the annular groove (10) is arranged in the blind bore (12). Scissors according to claim 3, characterized in that the annular groove (10) is arranged on the end of the blind bore (12) facing away from the end face of the screw nut (3; 15; 18). Scissors according to one of claims 3 and 4, characterized in that the screw nut (3) is designed as a knurled nut. Scissors according to one of claims 3 to 5, characterized in that the screw nut (15; 18) is designed as a polygonal nut. Scissors according to one of claims 1 to 6, characterized in that the flexible body bearing against the screw nut (18) and the wall (19) of the bore (20) of one scissor half (21) is designed as a molded part (22), the outside thereof the bore (20) and the inside of which is adapted to the diameter of the articulated screw (1) and which rests with an end face (23) on the end face of the nut (18) facing the bore (20) under pressure. Scissors according to claim 7, characterized in that the bore (20) has a constriction in its end region (24) facing away from the screw nut (18) and an enlargement as a circular recess in its end region (25) facing the screw nut (18) the transition region (26) between the two end regions (24, 25) is conical. Scissors according to claim 8, characterized in that the screw nut (18) is guided with a short neck extension (27) in the circular recess of the bore (20) or in a circular recess of the molded part (22). Scissors according to claim 9 or 10, characterized in that the end region (24) of the bore (20) facing away from the screw nut (18) has a rectangular punching.

Images