DE102018130991B4 - Torsion-resistant vial cutout for spirit level - Google Patents

Abstract

Method for producing a spirit level body (100) for a spirit level from a square tube (110), comprising the following steps: - providing a square tube (110) with four side walls (111, 112, 113, 114), - making one or more recesses (120) ) in the square tube (110) for receiving a vial, the one or more recesses (120) each having at least one free edge (121), - formation of a stiffening section (150) in the area of the one or more recesses (120) with at least one double wall (151), the double wall (151) being formed by bending over and / or kinking the at least one free edge (121) around a bending and / or kinking axis (153), in particular into the interior of the square tube (110) becomes.

Description

The invention relates to a method for producing a spirit level body from a square tube according to the preamble of claim 1 and a spirit level body according to the preamble of claim 8. Furthermore, the invention relates to a spirit level with a spirit level body according to the preamble of claim 9.

Spirit levels are widely used measuring devices. On construction sites in particular, spirit levels are exposed to heavy mechanical stress in daily use, albeit mostly unintentionally, due to falls or incorrect loading. A variant of a spirit level is the design with a square tube made of metal or aluminum, with at least one side wall of the square tube forming the support surface or measuring surface, which must be exactly flat for the required measurement accuracy. As a result of the mechanical stress, the measuring surface can be deformed, making the spirit level unusable and having to be replaced. The area of the longitudinal vials is particularly affected by the deformation, since the square tube for inserting the vials is cut out in certain areas. This cutout leads to a weakening of the material and to a reduced torsional stiffness or bending stiffness of the spirit level in the area of the vial.

In the prior art, an improvement in the rigidity of spirit levels is typically achieved by appropriate profiling on the outside and / or the inside of the square tube. Instead of a simple square tube, the spirit level can also be made with a tube that has a torsion-resistant H external profile or a double-T external profile. Alternatively, the base body of the spirit level is made with fiber-reinforced material.

The EP 1 857 778 B1 relates to a spirit level in which the inner surfaces of the frame have aluminum ribs which can be brought into engagement with a nose of the level holder so that the level holder is locked relative to the frame in a vertical direction.

The DE 20 2009 016 443 U1 describes the stiffening of a spirit level base body through a suitable choice of material. The main body consists of a wood-plastic composite material. A level holder is arranged in an opening. The vial itself is attached to the vial holder by gluing or welding in the connecting layer. Due to the wood fibers in the material, high strength and rigidity can be achieved with low weight at the same time.

The WO 2005/088 256 A1 shows a spirit level which is made by injection molding with thermoplastic material. The level body has at least one recess for a spirit level and reinforcement inserts made of fiber-reinforced plastic, these being at least partially materially connected to the level body.

The DE 44 01 944 A1 discloses a spirit level with an aluminum profile tube through which an inner wall penetrates in the middle between the outer walls, so that two channels are formed in the profile tube. The inner wall is intended to create a means which can bring about additional stiffening of the hollow profile for the level body. Recesses are provided in the walls to accommodate a spirit level. The inner wall can alternatively also be interrupted, so that two inner webs, which form a T-profile with the respective wall, result with a common alignment and at a distance from one another.

The DE 77 04 713 U relates to a level body with a plastic profile which has metal inserts extending over the entire length of the level body. The plastic profile has recesses into which the metal inserts are inserted. The metal inserts can be glued in the recesses of the plastic profile.

The disadvantage of the prior art is that fiber-reinforced materials are expensive. Manufacturing from a spirit level body with a torsion-resistant base profile also makes manufacturing more complex and / or increases the amount of material required. The object of the invention is to improve the state of the art and, in particular, to reduce the material costs for a torsion-resistant spirit level.

To avoid these disadvantages, the method specified in claim 1, the spirit level body specified in claim 8 and the spirit level specified in claim 9 are proposed. Optional, advantageous embodiments of the invention are specified in the dependent claims. It should be pointed out that the features and measures listed individually in the following description can be combined with one another in any technically meaningful manner and show further embodiments of the invention. The description additionally characterizes and specifies the invention, in particular in connection with the figures. If the following application text speaks of "bending over" or "bending axis", this also includes processes with "bending over" and "turning over" around a " Bending axis ”. If the term “spirit level body” is used, this applies not only to the fully formed body, but also to intermediate stages during the manufacturing process.

• - Bereitstellen eines Vierkantrohres mit vier Seitenwandungen,
• - Fertigen einer oder mehrerer Ausnehmungen in dem Vierkantrohr zur Aufnahme einer Libelle, wobei die eine oder die mehreren Ausnehmungen jeweils mindestens eine freie Kante aufweisen,
• - Ausbilden eines Versteifungsabschnitts im Bereich der einen oder der mehreren Ausnehmungen mit mindestens einer Doppelwandung, wobei die Doppelwandung durch Umbiegen und/oder Umknicken der mindestens einen freien Kante um eine Biege- und/oder Knickachse, insbesondere ins Innere des Vierkantrohrs, ausgebildet wird.

The invention relates to a method for producing a spirit level body for a spirit level from a square tube, comprising the following steps:

• - Provision of a square tube with four side walls,
• - Production of one or more recesses in the square tube for receiving a spirit level, wherein the one or more recesses each have at least one free edge,
• - Forming a stiffening section in the area of the one or more recesses with at least one double wall, the double wall being formed by bending over and / or folding over the at least one free edge about a bending and / or kinking axis, in particular into the interior of the square tube.

The method steps are preferably to be carried out in the order mentioned. The square tube forms the starting body for manufacturing the level body and is typically made of metal or aluminum. Other materials with corresponding properties can also be used. In addition to the four side walls, there are two initially open or non-closed end faces which, for example after completion of all process steps, can be closed with end caps to manufacture the spirit level. For example, by means of laser technology or milling, a recess is made in the square tube to accommodate the vial. The recess creates free edges in the square tube. Free edge means that no other or further side wall is adjacent. Two adjacent free edges can enclose a convex surface of the square tube. The stiffening section is formed in that such a free edge is bent over, bent over and / or turned over about a bend axis. As a result, a double wall is formed, which reinforces or stiffens the spirit level body precisely in the area of the recess. This means that it is no longer necessary to provide the entire level body with an inner profile or an outer profile, which saves material and also allows the weight of the level to be reduced.

In an advantageous development of the method according to the invention, the formation of the stiffening section is preceded by cutting into at least one side wall adjoining the recess, along at least one cutting line.

Starting from a free edge or towards a free edge, a side wall adjoining the recess is incised, so that the incision line resulting therefrom opens into the recess. The incision creates one or two additional free edges. In this way, two adjacent free edges can enclose a section or a convex corner area of the level body. This corner area is also delimited by or adjoins the articulation axis. The corner area is preferably bent around the bending axis to form the double wall. Such a corner area or envelope area can adjoin two, three or more free edges. By forming free edges with incision lines, the kinking around the kink axis can be carried out in a targeted manner and with little effort, without other areas of the level body being undesirably deformed.

The at least one free edge is preferably bent over and / or bent over when the stiffening section is formed into a double wall having an L-profile or a U-profile.

The four side walls of the level body enclose a, preferably single, common space. In principle, the free edge can be bent outwards towards the surroundings or inwards into the space. Since as far as possible all the outer surfaces of the spirit level body should be perfectly flat in order to create measuring surfaces, the free edges are typically to be bent inwards. The free edge can, for example, be bent inwards until it encloses a 90 ° angle for an L-profile with a side wall that has not been bent over, the origin of this 90 ° angle being arranged on or in the area of the bending axis. Alternatively, the free edge can be bent over by up to 180 ° for a U-profile until a surface adjoining the free edge lies flat against the inner surface of a non-bent side wall of the level body. In principle, all angles between 0 ° and 180 ° are possible. The stiffening area of the recess can thus be designed as a function of the desired connection stiffness or the space required for the vial to be inserted.

In a preferred embodiment, a square tube with a rectangular cross section with two wide side walls and two narrow side walls is provided and the at least one recess is at least partially within one of the narrow side walls manufactured, with one or more incision lines in one or both wide side walls, adjacent to the recess, are formed.

When forming the recess, a region of a narrow side wall is cut out, which preferably extends from a first wide side wall to a second wide side wall. When forming the recess, however, less or, alternatively, an area of the adjoining wide side walls can be cut out. After the wide side walls have been cut, they can be bent over in a manner already described. By bending over the wide side walls, the stiffening area can be enlarged compared to bending over narrow side walls.

The articulation axis is preferably formed parallel to a support surface or measuring surface of the level body. This facilitates the production of the stiffening section, since the elongated spirit level body can be moved or rotated around one of its longitudinal axes when it is folded over with a suitable tool, while the area of the free edge to be folded over is held stationary. This means that a less complex tool can be used. Alternatively, the spirit level body can also be held stationary in the tool while the free edge to be bent is moved.

In an optional but advantageous further development of the invention, two double walls are formed axially symmetrically with respect to a central axis at the same time or successively in time within the stiffening section. The central axis runs parallel to a longitudinal axis of the square tube or level body or coincides with an axis of symmetry along the longitudinal direction of the level body.

The stiffening section, in particular the double wall (s), is preferably formed with a punching tool and / or edging tool. The stiffening of the level body and thus the entire level is thus, unlike in the prior art, realized by mechanical processing or reworking of a square tube, preferably a cut square tube, using suitable tools. The square tube provided for the process can also have a profile, but does not have to be. Expensive composite materials can also be omitted.

Independent protection of the invention is claimed for a spirit level body, in particular manufactured according to one of the methods already described, with four side walls and one or more recesses arranged within the side walls for receiving at least one vial, preferably a longitudinal vial. The level body has a stiffening section with at least one bent and / or angled double wall with a preferably L-shaped or U-shaped profile or cross-sectional profile and the double wall (s) are designed as a receiving device for positively and / or non-positively receiving the vial in the recess .

The recess for receiving the spirit level is arranged at the edge of the spirit level body. By bending over a side wall, a projection protruding into the space is formed, the thickness, depth or some other dimension of the projection corresponding to a side wall thickness of the square tube. The receiving device can be designed with a clip device so that an adhesive connection between the level and the level body can be dispensed with. In the receiving device, for example, a lower limit for the housing can be formed, e.g. by folding the double wall again into the space between the level body around a further articulation axis, on which the housing of the vial or the vial holder rests or rests after assembly. Furthermore, the double wall can additionally have a toothing or the like for engagement or coupling with the housing of the spirit level, so that a displacement in the longitudinal direction of the level body and / or an unintentional slipping is prevented. The folded double wall can accordingly have embossments, bores or recesses for engagement or the toothing. These can preferably be carried out before the double wall is bent over about the bending axis.

The double wall is designed as a receiving device for the form-fitting, in particular play-free, and / or force-fitting reception of the vial or longitudinal vial in the recess. To accommodate the longitudinal vial, the stiffening section is thus arranged at the edge and optionally in the center with respect to a longitudinal axis of the level body.

Independent protection of the invention is also claimed for a spirit level, having a spirit level body, in particular a spirit level body in one of the designs already described, in particular manufactured according to one of the methods already described, with four side walls and one or more recesses arranged within the side walls for receiving at least one level, wherein the level body has a stiffening section with at least one bent and / or angled double wall, preferably with an L-shaped or U-shaped profile or cross-sectional profile. The double wall (s) are designed as a receiving device for positively locking and / or non-positively receiving the vial in the recess

• 1a eine Seitenansicht eines beispielhaften Vierkantrohrs aus dem Stand der Technik;
• 1b eine Seitenansicht eines beispielhaften Wasserwaagenkörpers aus dem Stand der Technik;
• 1c eine Draufsicht eines beispielhaften Wasserwaagenkörpers aus dem Stand der Technik;
• 2 eine Seitenansicht eines Verfahrensschritts in einer beispielhaften Ausführungsform der Erfindung;
• 3 eine Draufsicht eines Wasserwaagenkörpers in einer beispielhaften Ausführungsform der Erfindung;
• 4 eine Prinzipskizze einer geschnittenen Ansicht eines Wasserwaagenkörpers in einer beispielhaften Ausführungsform der Erfindung.

Further details, features and effects based on the invention emerge from the following description of exemplary embodiments and from the drawings. These show in:

• 1a a side view of an exemplary square tube from the prior art;
• 1b a side view of an exemplary level body from the prior art;
• 1c a top view of an exemplary prior art level body;
• 2 a side view of a method step in an exemplary embodiment of the invention;
• 3rd a plan view of a level body in an exemplary embodiment of the invention;
• 4th a schematic diagram of a sectional view of a level body in an exemplary embodiment of the invention.

In the different figures, parts that are the same or have the same function are always provided with the same reference symbols, which is why they are usually only described once. The specific embodiment shows a spirit level body for receiving a single longitudinal vial. However, spirit level bodies for holding several vials and / or longitudinal vials, some or all of which are provided with a stiffening section according to the invention, are expressly covered by the scope of protection of the application.

1a shows a square tube 110 , which is both the starting material for a spirit level body 100 (see. 1b and 1c ) from the prior art, as well as the starting material for a spirit level body according to the invention 100 (see. 3rd and 4th ) can represent. The square tube 110 has four side walls 111 , 112 , 113 and 114 on, due to the rectangular cross-section of the square tube 110 two wide side walls 111 and 112 ( 112 covered) and two narrow side walls 113 and 114 are trained. The square tube 110 can also be used on the outer surfaces 111a , 112a , 113a , 114a or interior surfaces 111a , 112i , 113i , 114i (see. 4th ) be profiled or smooth.

1b shows a level body 100 from the prior art after providing a square tube 110 (see. 1a) and after making a recess 120 for receiving a dragonfly, the recess 120 several free edges 121 having. The recess 120 to accommodate the vial is at the edge as a longitudinal vial on the level body 100 arranged and as a cutout in at least one narrow side wall 113 performed. When cutting out the recess 120 however, it can be less or alternatively, as shown, additionally a region of the adjoining wide side walls 111 , 112 to be cut out. Also is the recess 120 for the level centered with respect to a longitudinal axis 116 of the level body 100 arranged. The recess shown 120 is therefore of a total of eight free edges 121 limited, with three free edges each 121 the wide side wall shown to the viewer 111 and three free edges 121 the wide side wall hidden from the viewer 112 to lock. Two more free edges 121 close the recess 120 on the narrow side wall cut out for the dragonfly 113 a. Through the recess 120 is the level body 100 in the area of the recess 120 weakened and prone to damage or distortion 117 .

1c Figure 10 shows a plan view of a level body 100 with a twist 117 (indicated schematically). The top view enables a view through the recess 120 in the space 115 that of the four side walls 111 , 112 , 113 , 114 is surrounded. The twist 117 arises, for example, from improper, preferably central, loading on one of the four side walls 111 , 112 , 113 , 114 , thereby the measuring surfaces of the level body 100 become unusable. To counteract this is a stiffening section 150 (see. 2 , 3rd and 4th ) intended.

2 shows the cutting of the level body 100 along a cutting line 123 , based on an undamaged spirit level body 100 as in 1b , the exact geometries of course to the stiffening section to be manufactured 150 (see. 2 and 3rd ) are to be adjusted. Starting from a free edge 121 at the recess 120 or towards a free edge 121 is attached to the recess 120 adjoining wide side wall 113 incised. The same thing happens at the same time or successively in time on the second wide side wall, not shown 112 performed. The incision creates for each one, depending on their arrangement Cutting line 123 at least one additional free edge 121 . A total of three free edges 121 on the incised wide side wall 111 , of which two through the incision lines 123 have arisen close together with an articulated axis 153 a square or rectangular area. The articulated axis 153 runs parallel to a longitudinal axis 116 (see. 1b) of the level body 100 . By forming a total of three free edges 121 by incision lines 123 can do the buckling around the articulation axis 153 can be carried out in a targeted manner and with little effort, without the level body moving 100 undesirably deformed outside the square or rectangular area.

3rd shows the completed stiffening section 150 , in which the square or rectangular area becomes a U-shaped double wall 151 by twisting around the articulation axis 153 is shaped with the maximum possible kink angle of 180 °. In that the articulation axis 153 parallel to a longitudinal axis 116 (see. 1b) of the level body 100 can run if the body of the spirit level is bent 100 around its longitudinal axis 116 be rotated. This facilitates the manufacture of the stiffening section 150 , because the elongated spirit level body 100 can be rotated when folding with a comparatively simple tool, while the area of the free edge to be folded 121 is held stationary. Alternatively, the level body can also be used 100 be held stationary in the tool, while the free edge to be folded over 121 is moved. In this way, a profiling of an initially smooth-walled square tube can be made without a large amount of material 110 (cf. 1a) in the area of the weakened recess 120 can be achieved. The profiling achieved by this mechanical post-processing is described in more detail as follows.

4th shows a schematic basic sketch of a sectional illustration, the sectional plane being perpendicular to the longitudinal axis 116 (see. 1b) of the level body 100 in the area of the stiffening section 150 runs. Arranged to the left of the viewer is a first wide side wall 111 to a double wall 151 with an L-profile around a first articulation axis 153 bent over. Arranged to the right of the viewer is a second wide side wall 112 to a double wall 151 with a U-profile around a second articulation axis 153 bent over. Both wide side walls 111 , 112 can also be bent in the same way or at the same angle. The central axis 152 of the cross section is designed as an axis of symmetry in this case. The central axis 152 runs perpendicular to a longitudinal axis 116 of the square tube 110 or level body 100 . In other words: the free edge 121 can, for example, go inside into the space 115 be bent over until they have a wide side wall that is not bent over 111 includes a 90 ° angle for an L-profile, the origin of this 90 ° angle on or in the area of the articulation axis 153 is arranged. Alternatively, the free edge 121 further bent by up to 180 ° for a U-profile, until one reaches the free edge 121 adjoining surface flat on the inner surface 112i a wide side wall that is not bent over 112 of the level body 100 is present. In principle, all angles between 0 ° and 180 ° are possible. The gap 115 in the level body 100 is from the four inner walls 111i , 112i , 113i , 114i the side walls 111 , 112 , 113 , 114 of the square tube 110 (see. 1a) surround. Outward to the environment 122 show four outer walls 111a , 112a , 113a , 114a the side walls 111 , 112 , 113 , 114 of the square tube 110 (see. 1a) which measuring surfaces can be designed for the finished spirit level. By folding over a side wall 111 , 112 is one in the space 115 protruding projection formed, wherein the thickness, the depth or some other dimension of the projection of a side wall thickness of the square tube 110 (see. 1a) corresponds to. This projection can, for example, be a receiving device 154 have to accommodate a dragonfly. This profiling creates the stiffening section 150 , which, without the use of additional material, additionally strengthens the spirit level in its weakest area. Rather, the stiffening section is created 150 through mechanical post-processing.

List of reference symbols

100

Level body

110

Square tube

111

First wide side wall

112

Second wide side wall

113

First narrow side wall

114

Second narrow side wall

111a-114a

Exterior surfaces

111i-114i

Interior surfaces

115

Space

116

Longitudinal axis

117

Twisting

120

Recess

121

Free edge

122

Surroundings

123

Cutting line

150

Stiffening section

151

Double wall

152

Central axis

153

Articulated axis

154

Receiving facility

A-A

Cutting line

Claims (9)

Method for producing a spirit level body (100) for a spirit level from a square tube (110), comprising the following steps: - Provision of a square tube (110) with four side walls (111, 112, 113, 114), - Production of one or more recesses (120) in the square tube (110) for receiving a spirit level, the one or more recesses (120) each having at least one free edge (121), - Forming a stiffening section (150) in the area of the one or more recesses (120) with at least one double wall (151), the double wall (151) being bent over and / or folding over the at least one free edge (121) by a bending and / or the articulation axis (153), in particular in the interior of the square tube (110). Procedure according to Claim 1 , characterized in that the formation of the stiffening section (150) is preceded by a cutting of at least one side wall (111, 112) adjoining the recess (120) along at least one cutting line (123). Procedure according to Claim 1 or 2 , characterized in that the at least one free edge (121) is bent over and / or bent over when the stiffening section (150) is formed to form a double wall (151) having an L-profile or a U-profile. Method according to one of the preceding claims, characterized in that a square tube (110) with a rectangular cross-section with two wide side walls (111, 112) and two narrow side walls (113, 114) is provided and the at least one recess (120) is at least partially is manufactured within the narrow side wall (113, 114), one or more incision lines (123) being formed in one or both of the wide side walls (111, 112) adjacent to the recess (120). Method according to one of the preceding claims, characterized in that the articulation axis (153) is formed parallel to a support surface or measuring surface of the level body (100). Method according to one of the preceding claims, characterized in that within the stiffening section (150) two double walls (151) are formed axially symmetrically with respect to a central axis (152) at the same time or successively in time. Method according to one of the preceding claims, characterized in that the stiffening section (150), in particular the double wall (s) (151), is formed with a punching tool and / or edging tool. Spirit level body (100), in particular produced by a method according to one of the Claims 1 - 7th , with four side walls (111, 112, 113, 114) and one or more recesses (120) arranged within the side walls (111, 112, 113, 114) for receiving at least one level, the level body (100) having a stiffening section (150 ) with at least one bent and / or bent double wall (151), preferably with an L-shaped or U-shaped profile, characterized in that the double wall (s) (151) as a receiving device (154) for form-fitting and / or force-fitting reception of the vial are formed in the recess (120). Spirit level, having a spirit level body (100), in particular produced by a method according to one of the Claims 1 - 7th , with four side walls (111, 112, 113, 114) and one or more recesses (120) arranged within the side walls (111, 112, 113, 114) for receiving at least one level, the level body (100) having a stiffening section (150 ) with at least one bent and / or bent double wall (151), preferably with an L-shaped or U-shaped profile, characterized in that the double wall (s) (151) as a receiving device (154) for form-fitting and / or force-fitting reception of the vial are formed in the recess (120).

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