EP0489027B1 - Hole punch with positioning rail - Google Patents

Abstract

Disclosed is a hole punch with a base (10) designed as a collector for the clippings produced and made of flexible plastics material. A snap-in catch (16) engages in a recess (14) running transversely across the collector. A positioning rail (18) with a positioning stop (20) for the sheets of paper in which holes are to be punched is mounted so that it can be moved through the snap-in catch (16) and can be locked with the catch in different positions.

Description

The invention relates to a letter punch with a bottom part designed as a chip tray made of flexible plastic material and a displaceably arranged relative to the bottom part, having an end stop for the document to be punched, resiliently lockable stop rail in different positions.

In the case of letter punches of this type, the chip trays which serve as a support surface for the punch are detached from the lower part of the punch for emptying or partially folded down. In order to facilitate the detachment or folding down of the chip pan and to ensure that the punch hole lies as non-slip on its base, the base part is made of a relatively soft and resilient plastic material.

In a known letter punch of this type (DE-A-3740425), the stop rail is guided directly in a rectangular channel of the base part which is open on both sides and engages with corresponding locking cams in corresponding locking recesses on the transverse walls of the rectangular channel. However, it has been shown that due to a different stiffening of the rectangular channel, the flexible transverse walls yield unevenly when the latching cams slide past between the individual latching depressions and therefore oppose the shifting of the stop rail with differently sized resistances. There in addition, the locking cams in the soft plastic material of the transverse walls are inaudible and, especially when you quickly move the stop rail, do not noticeably snap into the locking recesses, if the operator is used inattentively there is a risk of moving the stop rail beyond the prescribed locking position and thereby punching the paper in the wrong place .

The invention is therefore based on the object to improve the known letter punch in such a way that a uniform and noticeable locking of the stop rail is ensured in all locking positions.

To achieve this object, the features specified in the characterizing part of claim 1 are proposed. Further advantageous refinements and developments of the invention result from the dependent claims.

The invention is based on the idea of making the locking connections between the stop rail and the base part evenly strong and easier to feel by suitable material pairing or constructive training in the locking area, without, however, impairing the slip resistance of the contact surface and the detachability of the base part. For this purpose, according to the invention, the stop rail is guided in a latching piece which can be inserted into a recess in the bottom part and anchored immovably in the recess and can be latched in different positions with the latching piece.

In order to reduce the abrasion between the stop rail and the locking piece and thus to increase the service life of the stop rail and the locking piece, the locking piece and the stop rail are advantageously made of differently hard plastic materials that are harder than the plastic material of the base part. The locking piece expediently consists of a plastic material that is harder than the plastic material of the stop rail. The preferred material pairing for the locking piece is polyoxymethylene (POM) and a modified polystyrene for the stop rail.

According to an advantageous embodiment of the invention, the stop piece which is latched in the locking piece and has a U-shaped cross section rests with the lower edges of its side walls against the bottom of the locking piece which is U-shaped in cross section and with the outer surfaces of its side walls against the inner surfaces of the locking piece side walls. A preferred embodiment of the invention provides that the side walls of the locking piece each have an elastically deformable transverse to the side wall surface, separated by an elongated opening from the bottom of the locking piece material bridge with a locking cam formed on the inner surface of the material bridge. The opening is expediently limited on the outside by the inner surface of the side wall which is extended to the underside of the locking piece base. The arrangement of the locking cams on a material bridge allows for the given material pairing of the stop rail and locking piece by varying the opening length Optimization of the spring force or the elasticity of the snap connection.

The side walls of the stop rail advantageously have latching depressions on their outer surfaces for the engagement of the latching cams formed on the material bridges of the latching piece.

According to a further preferred embodiment of the invention, the locking piece has on its outer end face facing the stop of the stop rail two shoulders projecting over the outer surface of the locking piece side walls, which shoulders together with at least one locking projection projecting over the underside of the locking piece bottom, provided with an inclined surface and a steep rear flank ensure anchoring in the base part without play. In the assembled state, the locking piece expediently rests with the rear flank of the locking projection against a recess edge in the base part and with the shoulders against an outer wall of the base part.

According to a further advantageous embodiment of the invention, the latching projection resting against the recess edge in the bottom part is held in position by at least one supporting cam which projects in the region of the latching projection beyond the upper edge of the latching piece side walls and which rests against a material bridge of the bottom part when the latching piece is anchored.

In order to avoid pinching the fingers between the stop and the punch hole when inserting the stop rail, a stop cam is formed on the top of the locking piece base, which at a distance from the inside when the locking cams snap into the stop-side first recesses of the stop rail against one that connects the side walls of the stop rail cross bar arranged from the stop. The stop cam can be arranged on the end face of the locking piece facing the stop.

In order to make it difficult to pull it out completely when moving the stop rail, according to a further preferred embodiment of the invention, the locking piece has a molded-in area in the area of the material bridges on the top of the locking piece bottom, when the locking cams snap into the insertion-side first locking recesses of the stop rail against an insertion-side Stop cams abutting the front side wall of the stop rail. In order not to break off the two stop cams formed on the locking piece base when the stop rail is completely pulled out, the end faces of the stop cams on the insertion side are appropriately beveled.

According to a further advantageous embodiment of the invention, the stop rail in the locking piece is at the top by at least two, in the area of the upper edges of the locking piece side walls opposite each other in pairs, each projecting inwards stepped guide edge of the stop rail engaging guide cams held and guided. Two pairs of guide cams arranged on the material bridges at a distance from one another are expediently provided.

In order to prevent the stop rail from getting caught in the recess or at the outlet opening of the recess opposite the latching piece, the stop rail expediently has an inclined surface inclined towards the end face at its end opposite the stop.

Fig. 1

eine Draufsicht auf das Bodenteil eines Brieflochers mit Raststück und Anschlagschiene;

Fig. 2

einen Längsschnitt durch das Bodenteil nach Fig. 1 mit eingeschobener Anschlagschiene;

Fig. 3 a und b

eine Längsseitenansicht und eine Draufsicht der im Raststück verrasteten Anschlagschiene;

Fig. 4 a bis c

eine Unterseiten-, Längsseiten- bzw. Oberseitenansicht der Anschlagschiene;

Fig. 4 d

einen Querschnitt durch die Anschlagschiene entlang der Linie A-A der Fig. 1;

Fig. 5 a bis c

eine Oberseiten-, Seiten- bzw. Unterseitenansicht des Raststücks;

Fig. 5 d

einen Längsschnitt durch das Raststück.

The invention is explained in more detail below with reference to an exemplary embodiment shown schematically in the drawing. Show it

Fig. 1

a plan view of the bottom part of a letter punch with locking piece and stop rail;

Fig. 2

a longitudinal section through the bottom part of Figure 1 with inserted stop rail.

3 a and b

a longitudinal side view and a plan view of the stop rail locked in the locking piece;

4 a to c

a bottom, long side and top view of the stop rail;

Fig. 4 d

a cross section through the stop rail along the line AA of Fig. 1;

Fig. 5 a to c

a top, side and bottom view of the locking piece;

Fig. 5 d

a longitudinal section through the locking piece.

The punch hole base part 10 shown in FIGS. 1 and 2 can be snapped onto the lower part of a punch hole punch (not shown) from below. It forms a schnitzel pan 12 and serves with its bottom 13 as a non-slip support surface for the letter punch. A locking piece 16 is anchored non-displaceably in a recess in the bottom part 10 designed as a rectangular channel 14. In the locking piece 16, a stop rail 18 with a stop 20 for the document to be punched is displaceable and can be snapped into positions corresponding to several different paper formats.

The rear part of the base part 10, which forms the chip pan 12, can be folded down from the lower part of the hole by a bending axis 21 and has interrupted side walls 22 ′, 22 ″ for folding down in the region of the bending axis 21. In the area of its rear edge 23, the chip pan 12 is provided with a button-shaped actuating element 24 which can be releasably latched onto the lower part of the punch. Two viewing windows 26 make it possible to check the filling level of the paper chips in the chip tray 12 from the outside.

The front part of the base part 10 has two transverse walls 30, 32 which are parallel to its front edge 28 and are arranged at a distance from one another, which are formed both on the side wall parts 22 ″ and on the base 13 and on their upper and lower edges by material bridges 36, 38 , 40, 42, 44 are connected to one another. The material bridges 36, 38 between the upper edges of the transverse walls 30, 32 are each offset in the longitudinal direction with respect to the material bridges 40, 42, 44 between the lower edges of the transverse walls 30, 32. Two further material bridges 46 and 48 in the area of the side wall parts 22 ″ delimit two front openings of the rectangular channel 14 formed by the transverse walls and the material bridges. Reinforcing ribs 50 arranged on the outer surfaces of the transverse walls 30, 32 serve to stiffen the rectangular channel 14.

The locking piece 16 which can be anchored in the rectangular channel 14 and which is shown in FIGS. 5 a to d has a U-shaped cross section and essentially consists of two side walls 52, 54 and a locking piece base 56 connecting the side walls 52, 54. At its stop 20 of the stop rail 18 facing the outer end face is the locking piece 16 with two shoulders 60, 62 projecting beyond the outer surfaces of the locking piece side walls 52, 54 and in the area of the opposite inner end face with two overhanging the underside of the locking piece bottom 56, an inclined surface 64 and a steep rear flank 66 having locking projections 68. That from a relatively hard plastic material, preferably made of polyoxymethylene (POM), existing locking piece 16 can be inserted together with the stop rail 18 into the rectangular channel 14 and anchored there. After assembly, the shoulders 60, 62 rest against the side walls 22 ″ of the base part 10 from the outside, while the rear flanks 66 of the latching projections 68 engage behind the inner edge of the material bridge 42. The locking piece 16 is thus anchored in the rectangular channel 14 without play. In the area of the locking projection 68, a supporting cam 70 projecting beyond the upper edge of the locking piece side walls 52, 54 lies against the underside of the material bridge 36 and bends it slightly upwards. Due to the elastic restoring force of the material bridge 36, the support cams 70 and thus also the locking projections 68 are pressed down and thus held in their anchoring. The height of the rear flanks 66 of the latching projections 68 corresponds exactly to the material thickness of the material bridge 42, so that the latching projections 68 do not project downward beyond the contact surface of the base part 10.

The stop rail 18 shown in FIGS. 4 a to d likewise has an approximately U-shaped cross section and lies with the free edges 72 of its side walls 74, 76 against the locking piece base 56 and with its outer surfaces 78, 80 against the inner surfaces of the locking piece side walls 52 , 54 at. The stop rail 18 is moved upwards by two guide cam pairs 59, 61 arranged at a distance from one another in the region of the upper edges of the locking piece side walls 52, 54, the pairs of these inwards protruding cams engage in stepped guide grooves 58 of the stop rail 18 in their guidance. The stop rail 18 consists of a softer plastic material than the locking piece 16, for example of modified polystyrene. Due to the difference in hardness between the stop rail 18 and the locking piece 16, the mutual abrasion can be reduced and thus the service life of both parts can be extended.

To lock the stop rail 18, the locking piece 16 has two locking cams 82, 84 integrally formed on the inner surfaces of its side walls 52, 54, each of which at one of the predetermined intervals from the outside in the side walls 74, 76 of the stop rail 18 are molded-in recess pairs 85a, 85b , 85c, 85d, 85e or 85f. In order to ensure a constant locking at all times, the side walls 52, 54 of the locking piece 16 in the area of the locking cams 82, 84 are separated from the locking piece bottom 56 by two elongated openings 86, 88, which extend outwards through the inner surfaces of the locking piece bottom 56, which are extended to the underside of the locking piece bottom 56 Side walls 52,54 are limited. The material bridges 90, 92 formed within the side walls can be resiliently bent outwards as soon as the locking cams 82, 84 are pushed out of one of the locking recess pairs 85a, 85b, 85c, 85d, 85e or 85f when the stop rail 18 is moved. For a given locking piece material, the elastic spring force can be determined by the length of the openings 86, 88 and by the height and wall thickness of the locking piece side walls 52, 54 the locking cams 82, 84 which are lifted out of the locking recesses when the stop rail 18 is moved against its side walls 74, 76 can be set.

In order to prevent the fingers from getting caught between the stop 20 and the lower part of the punch when the stop rail 18 is displaced, a stop cam 94 is formed on the top of the catch piece bottom 56, which against the inside when the catch cams 82, 84 snap into the stopper pair 85a on the stop side arranged at a distance from the stop 20, the transverse walls 96 connecting the side walls 74, 76 of the stop rail 18 (FIG. 2).

Another stop cam 98 projecting upward in the region of the locking cams 82, 84 above the locking piece base 56 lies when the locking cams 82, 84 engage in the first locking recesses 85f on the insertion side against an insertion-side end wall 100 of the stop rail 18 and thereby secures the stop rail 18 against complete pull-out. The end faces of both stop cams 94 and 98 are chamfered, so that the stop rail 18 can be removed without breaking off the stop cams 94, 98 if necessary. When the stop rail 18 is removed, the end wall 100 slides over the inclined surfaces of the stop cams 98 and 94 while lifting the end of the stop rail on the insertion side.

At its end opposite the stop 20, the stop rail 18 has an inclined surface 102 which is inclined towards the front side wall 100 and which facilitates the insertion of the stop rail 18 into the outlet-side opening of the rectangular channel 14 and prevents the stop rail 18 from striking the web 48 is and hooked between the bottom part 10 and the punch base.

Claims (20)

1. Paper punch comprising a bottom part (10̸) of flexible plastic material serving as a waste receptacle and a positioning rail (18), which is arranged to be displaceable relative to the bottom part (10̸) and which comprises an end stop (20̸) for the document to be punched and which is resiliently detented in various positions, characterised in that the positioning rail (18) is guided in a detent element (16), which is inserted into a cut-out (14) of the bottom part (10̸) and indisplaceably anchored in the cut-out (14), and is detentable with the detent element (16) in different positions.
2. Paper punch according to claim 1, characterised in that the detent element (16) and the positioning rail (18) are made of plastic materials of different hardness which are harder than the plastic material of the bottom part (10̸).
3. Paper punch according to claim 1 or 2, characterised in that the detent element (16) is made of a plastic material which is harder than that of the positioning rail (18).
4. Paper punch according to one of claims 1 to 3, characterised in that the detent element (16) is made of polyoxymethylene (POM).
5. Paper punch according to one of claims 1 to 4, characterised in that the positioning rail (18) is made of modified polystyrene.
6. Paper punch according to one of claims 1 to 5, characterised in that the U-shaped positioning rail (18), which is detented in the detent, element (16), abuts with the free edges (72) of its lateral walls (74, 76) against the bottom (56) of the cross-sectionally U-shaped detent element (16), and with the external surfaces of its lateral walls (74, 76) against the internal surfaces of the lateral walls (52, 54) of the detent element.
7. Paper punch according to claim 6, characterised in that that the lateral walls (52, 54) of the detent element (16) comprise a respective material bridge (90̸, 92), which is elastically deformable transversely to the surface of the lateral wall and separated from the bottom (56) of the detent element (16) by an elongated passage (86, 88), comprising a detent cam (82, 84) which is integrated witn the internal surface of the material bridge (90̸, 92).
8. Paper punch according to claim 7, characterised in that the passage (86, 88) is outwardly defined by the internal surface of the lateral wall (52, 54), which is extended to the bottom of the base of the detent element (56).
9. Paper punch according to claim 7 or 8, characterised in that the lateral walls (74, 76) of the positioning rail (18) have on their external surfaces detent grooves (85a, 85b, 85c, 85d, 85e, 85f) for engagement of the detent cams (82, 84) which are integrated on the material bridges (90̸, 92) of the detent element (16).
10. Paper punch according to one of claims 6 to 9, characterised by at least two guide cams (59, 61), which are positioned in pairs opposite each other in the area of the top edges of the lateral walls (52, 54) of the detent element and, protrude inwardly and engage a respective offset guide edge (58) of the positioning rail (18).
11. Paper punch according to one of claims 6 to 10̸, characterised in that the detent element (16) has at its external end which is facing towards the stop (20̸) of the positioning rail (18) two shoulders (60̸, 62) which protrude over the external surfaces of the lateral walls (52, 54) of the detent element.
12. Paper punch according to one of claims 6 to 11, characterised by at least one detent protrusion (68) which protrudes over the bottom side of the detent element bottom (56) and is provided with a slanted surface (64) and a steep rear flank (66).
13. Paper punch according to claim 12, characterised in that the detent element (16), which is anchored in the bottom part (10̸), abuts playfree with the rear flank (66) of the detent protrusion (68) against a cut-out edge in the bottom part (10̸), and with the shoulders (60̸), 62) against an external wall (22'') of the bottom part (10̸).
14. Paper punch acccrdina to claim 12 or 13, characterised by at least one respective support cam (70̸), which in the area of the detent protrusion (68) protrudes over the top edge of the lateral walls (52, 54) of the detent element and which, when the detent element (16) is anchored, abuts from underneath against a material bridge (36) of the bottom part (10̸).
15. Paper punch according to one of claims 6 to 14, characterised in that the lateral walls (74, 76) of the positioning rail (18) are at the abutment side connected by a transverse web (96) which is arranged at a distance from the stop (20̸).
16. Paper punch according to claim 15, characterised by at least one stop cam (94) which is integrated on the end of the detent element (16) which faces towards the stop (20̸) at the top of of the detent element bottom (56), and which abuts from the inside against the transverse web (96) of the positioning rail (18) when the detent cams (84, 94) engage the first detent grooves (85a) of the positioning rail, as seen in the direction of abutment.
17. Paper punch according to one of claims 6 to 16, characterised in that the lateral walls (74, 76) of the positioning rail (18) are connected at the insert end opposite the stop (20̸) by a lateral end wall (10̸0̸).
18. Paper punch according to claim 17, characterised by at least one stop cam (98), which is integrated in the area of the detent cams (82, 84) at the top of the detent element bottom (56), and which abuts from the inside against the lateral end wall (10̸0̸) of the positioning rail (18) when the detent cams (82, 84) engage the first detent grooves (85f) of the positioning rail (18), as seen in the direction of insertion.
19. Paper punch according to one or claims 16 to 18, characterised in that the ends of the detent cams (94, 98) on the side of insertion are slanted.
20. Paper punch according to one of claims 17 to 19, characterised in that the positioning rail (18) comprises at its end opposite the stop (20̸) a slanted surface (10̸2) which is slanted towards the lateral end wall (10̸0̸).

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