CA2311074A1

CA2311074A1 - Scissors having an action plate

Info

Publication number: CA2311074A1
Application number: CA002311074A
Authority: CA
Inventors: Helmut Boning
Original assignee: DOVO STAHLWAREN BRACHT GmbH and Co KG
Current assignee: DOVO STAHLWAREN BRACHT GmbH and Co KG
Priority date: 1999-06-10
Filing date: 2000-06-08
Publication date: 2000-12-10
Also published as: ES2176145T3; EP1059149B1; ATE217238T1; PT1059149E; EP1059149A1; DE29910126U1; DK1059149T3; DE50000158D1

Abstract

The invention concerns a pair of scissors having an action plate mounted in a countersink in the lifting flank of one of the two parts of the scissors, the lifting flank of the other part of the scissors sliding on the exposed plate surface of said action plate when being opened and closed.

Description

Scissors Having An Action Plate The invention concerns a pair of scissors having an action plate mounted in a countersink in the lifting flank of one of the two parts of the scissors, the lifting flank of the other part of the scissors sliding on the exposed plate surface of said action plate when being opened and closed.
As is known, scissors have an action position on the blade side of the hinged bolt which, as an abutment, absorbs the force acting approximately at right angles to the plane of the closing and opening movement, especially when the scissors are being closed. Whether or not the scissors have a uniform movement during closing, i.e., for example, also when the two cutting edges of the blades meeting one another are not completely symmetrical, depends on the construction of the action position.
The action position can, for example, consist of polished surfaces of the two scissor parts, having adjacent free cuts on the blade side. The free cuts produce the lifting flank or so-called half-moon of the two scissor parts.
It is substantially less expensive to place a spring plate between the scissor parts, said plate spring being passed through on its one end by the hinged bolt and whose other tapered end engages in a grain situated on the blade end of the hinged bolt in the one scissor part. Howevever, spring plates seldom result in a uniform movement of the scissors, exhibit premature fatigue, can then shift out of their set position and promote soiling of the scissors in the articulated area.

2 The scissors of the type mentioned in the introduction have a construction that is more advantageous vis-a-vis the latter.
The action plate, which usually consists of PTFE, can have a lamellar, semicircular or circular contour, is usually pressed into its countersink and offers a sufficiently large surface to prevent the other scissor part from tipping or tilting. In addition, the exposed plate surface, which protrudes e.g. 0.2 mm beyond the articulated surface of the scissor part in question, prevents a grinding of the counter articulated surface of the other scissor part.
The object of the invention is a pair of scissors of the aforementioned type which exhibit an even more uniform movement, even with slight deficiencies in the evenness of the cutting edges meeting one another or/and after many years or due to intensive use.
According to the invention, this object is solved thereby that the action plate is flexibly mounted in the countersink.
At least, this mounting, which is above all flexible, offsets to a great extent slight unevennesses of the cutting edges of the scissor parts caused by manufacturing or use which would otherwise result in an uneven action. In principle, the same is also true for unevennesses of the lifting flank which could at worst even be omitted or replaced by a simple free grinding.
The countersink can be graduated to accommodate the flexible support means for the action plate (claim 2).
In particular, the flexible support of the action plate can consist of an O-ring situated in the countersink, preferably

3 on its lower step (claim 3). ' The O-ring is preferably glued into the countersink (claim 4) .
Alternatively, the O-ring may also be held in a back or under cut which can e.g. be created by erosion.
In order to securely hold the action plate in the countersink, it preferably passes into a bore having a diameter which is reduced vis-a-vis the diameter of the countersink and the action plate has a peg engaging in the bore (claim 5). The bore can be a through-hole or a blind hole.
Preferably, the O-ring surrounds the peg of the action plate so as to be resistant to friction (claim 6).
Tests have shown that the 0-ring should at best have a Shore hardness in the range of A70 P 583, so that, on the one hand, the action plate can, above all, absorb the counter forces acting on it, also at right angles to its exposed surface, on the other hand, that it does not shift into the countersink under these counter-acting forces (claim 7).
An embodiment of a pair of scissors according to the invention is illustrated in a simplified form in the drawing, showing:
Figure 1 a top view onto the scissors and Figure 2 a first embodiment of the articulated area of the scissors in an enlarged section along the line II-II in Figure 1 and Figure 3 a second embodiment of the articulated area in an enlarged section along the line II-II in Figure 1.

4 The scissor parts 1 and 2 of the!scissors shown in Fig. 1 are, as usual, connected by a hinged bolt 3. In the area of the so-called half-moon of the scissor part 2, limited by the line 4, an action plate 5 is mounted in said scissor part 2 in such a way that its exposed, visible plate surface protrudes slightly, e.g. 0.2 mm, beyond the half-moon or the lifting flank, so that the half-moon of the scissor part 1 (not seen in the figure) is supported on said plate surface during opening and closing.
The action plate 5 is supported in the scissor part 2 so as to be, in particular, vertically flexible. The sections shown in Figures 2 and 3 show two embodiments. In both cases, the action plate 5, preferably consisting of PTFE, has a plate head 5a and a plate peg 5b. The plate head 5a is mounted to a great extent in a graduated countersink 6 having a central bore 7. Said bore 7 can be a blind bore (Fig. 2) or a through-bore (Fig. 3).
An O-ring 8 sits in the countersink 6, on its lower step, in both embodiments, said O-ring 8 surrounding the peg 5b of the action plate 5, while its plate head 5a rests on the O-ring 8.
As a result, the action plate 5 is above all mounted so as to be slightly flexibly movable in direction of the double arrow 10. For this reason, it can offset various contact pressures occurring during opening and, above all, during closing in the area of the lifting flank of the two scissors parts 1 and 2 in direction of the double arrow 10. The various contact pressures can be caused by e.g. manufacturing inaccuracies of the lifting flank, wear, foreign bodies or slight unevennesses of the cutting edges la, 2a of the scissor parts 1 and 2.
In the embodiment according to Fig. 2, the O-ring 8 is glued into the lower step of the countersink 6, as shown at 9.
In the embodiment according to Fig . 3 , the O-ring 8 is held in the lower step of the countersink 6 so as to be positively locked, i.e. thereby that the latter has a slight undercut.
An undercut of this type can be produced without difficulty, in particular when the countersink is created or finished by electroerosion.

Claims

1. Scissors having a action plate (5) mounted in a countersink (6) in the lifting flank (in the half-moon) of one of the two scissor parts (1, 2), the lifting flank (of the half-moon) of the other scissor part sliding on the exposed plate surface of said action plate (5) during opening and closing, characterized therein that the action plate (5) is flexibly mounted (via 8) in the countersink (6).

2. Scissors according to claim 2, characterized therein that the countersink (6) is graduated.

3. Scissors according to claim 1 or 2, characterized therein that the flexible mounting of the action plate (5) consists of an O-ring (8) situated in the countersink (6).

4. Scissors according to any one of claims 1 to 3, characterized therein that the O-ring (8) is glued into the countersink (6).

5. Scissors according to any one of claims 1 to 4, characterized therein that the countersink (6) protrudes into a bore (7) having a diameter that is reduced vis-à-vis the diameter of the countersink (6) and that the action plate (5) has a peg (5b) engaging in the bore (7).

6. Scissors according to claim 5, characterized therein that the O-ring (8) surrounds the peg (5b) of the action plate (5) so as to be resistant to friction.

7. Scissors according to any one of claims 3 to 6, characterized therein that the O-ring (8) has a Shore hardness in the range of A70 P 583.