Extendable folding rule

Abstract

Extendable articulated measuring rod (1) constructed from several measuring elements arranged one above the other, wherein the individual measuring elements (2) are connected to one another via a tongue and groove connection, wherein - the uppermost measuring element (2) has a smooth upper side (3) and on its underside (4) has a continuous outwardly widening bung (7) extending from a flat receiving area (5) for a stop web (6) of the underlying measuring element (2) to the end of the measuring element (2) in the longitudinal direction, - as a counterpart, the lowest measuring element (2) has a smooth underside (4) and on its upper side (3) has a groove (8) extending from a stop web (6) to the end of the measuring element and widening inwards, - the middle measuring elements (2) arranged between the two outer measuring elements (2) each have on their upper sides (3) a groove (8) extending from a stop web (6) to the end of the measuring element (2) and widening inwards, and on their lower sides (4) each have a bung (7) extending from a flat receiving area (5) for a stop web (6) of the underlying measuring element (2) to the end of the measuring element (2) and widening outwards, - the bungs (7) and the grooves (8) are designed as a connection between the measuring elements (2) and at the same time as a guide for pulling apart and pushing together the articulated measuring rod (1), - additional longitudinally extending bung grooves (9) are arranged in the bungs (7) for arranging and receiving locking elements, - wherein the measuring elements (2) have locking elements which are matched to one another and are provided for locking and fixing the measuring elements (2) in the fully extended and fully retracted state, characterized in that the locking elements are permanent magnets (17, 18) integrated in the measuring elements (2), wherein a larger permanent magnet (17) is firmly seated in a bore in the inwardly widening groove (8) and projects beyond the bottom thereof into the bung groove (9) of the adjacent measuring element (2), while a smaller permanent magnet (18) is flush with a bore in the bung groove (9), wherein the permanent magnets (17, 18) are arranged such that the larger permanent magnet (17) comes to rest above the smaller permanent magnet (18) after the measuring element (2) has been extended and is fixed in this position due to the magnetic forces.

Description

TECHNICAL FIELD

[0001] The present invention relates to an extendable folding rule which is intended to be used as a faster and more convenient alternative to the foldable folding rule, wherein the extendable folding rule is also intended in particular as a niche measuring stick. STATE OF THE ART

[0002] Folding rules and other simple measuring instruments are still indispensable basic equipment in trades and construction today. They allow for the quick inspection of components or the precise measurement of lengths, widths, heights, and distances. The most well-known measuring instrument is the folding rule, a folding measuring device with two measuring edges, typically used for lengths of up to two meters. Rulers, tape measures, and straightedges are also used as simple tools.

[0003] One disadvantage of the folding or unfolding ruler is that users often find unfolding the ruler annoying, time-consuming, and cumbersome. Furthermore, the folding ruler is prone to breaking at the hinge if used carelessly or improperly, rendering the ruler useless.

[0004] As an alternative to a folding ruler, a tape measure, usually a flexible, roll-up tape made of steel, coated canvas, or plastic, can be used for quick measurements. While this prevents the measuring tool from breaking, the handling of the tape measure, when used by one person, only allows measurements corresponding to approximately twice the person's arm length, making it unsuitable for many measuring operations, especially in the trades.

[0005] DE 27 19 512 A1 describes an extendable niche measuring rod, designed like a car antenna and telescopically, that allows niches to be measured in a single step. A new type of sequential numbering is used, allowing the niche spacing to be read precisely in the center of the measuring rod.

[0006] The subject of utility model DE 20 2006 013 035 U1 is a telescopic folding rule comprising several telescopically connected tubes of rectangular or other cross-sections, with the tube with the larger cross-section having an observation window for viewing a scale. The telescopic folding rule is intended particularly for measuring niches or internal dimensions.

[0007] Telescopic measuring rods, which usually work with smaller, telescopic tubes as measuring elements, often have the disadvantage that measurement inaccuracies can occur if the tubes are pulled apart incompletely or not in the correct order.

[0008] We also offer wooden folding rules with extendable brass tongues for internal measurements. The top section of the fold-out wooden folding rule has an extendable brass tongue integrated into it, which can then be used to carry out internal measurements.

[0009] DE 26 01 240 A1 discloses a folding rule in which each measuring element is designed as a metallic hollow profile with a trapezoidal cross-section, the longer trapezoidal side of which has a continuous longitudinal slot, while the shorter trapezoidal side of which carries two outwardly inclined guide rails and all measuring elements, when pushed into one another, engage with their longitudinal slot over the guide rails of the adjacent measuring element.

[0010] The subject of DE 10 2007 027 737 A1 is a device for measuring length with at least two interacting slide rails that can be moved longitudinally toward and toward each other. The measuring elements of the device are connected to each other via a tongue and groove connection. The locking and securing of the measuring elements is achieved via mechanical locking elements.

[0011] The German utility model DE 88 08 027 U1 describes a variably adjustable length measuring device starting from a foldable rod, which is constructed from paired measuring elements into which internal probes are inserted, wherein the measuring elements are designed with a dovetail-shaped guideway.

[0012] DE 10 2007 010 336 A1 describes a meter stick or a folding rule with magnetic rods, whereby the magnetic elements are intended to allow the rods to adhere to a ferrous metal surface of a body during the measuring process.

[0013] EP 4 209 750 A1 describes a conventionally foldable folding ruler, some of the links of which are equipped with magnets, whereby the ruler is to be fixed to sheet metal frame elements with the aid of the magnets for marking or cutting.

[0014] Based on this prior art, the objective of the present application is to offer an extendable folding rule or folding ruler that offers advantages over the prior art and is easy and safe to handle, making it an improved alternative to the conventional folding ruler. The folding ruler can also be used as a niche ruler. A further advantage over conventional folding rulers is that the measuring elements can no longer collapse when measuring sideways, allowing the user to easily measure a length corresponding to the length of the ruler with the folding ruler according to the invention, even with an outstretched arm. PRESENTATION OF THE INVENTION

[0015] The object is achieved by a folding measuring stick according to claim 1. Further possible embodiments of the invention are specified in particular in the dependent claims.

[0016] The inventive solution consists of an extendable measuring rod made up of several measuring elements arranged one above the other, with the individual measuring elements being connected to one another via a tongue and groove connection.

[0017] The uppermost measuring element has a smooth upper side and on its underside has a continuous, outwardly widening bung extending from a flat receiving area for a stop bar of the underlying measuring element to the end of the measuring element in the longitudinal direction.

[0018] In contrast, the lowest measuring element has a smooth underside and on its upper side has a groove that runs from a stop bar to the end of the measuring element and widens inwards.

[0019] The middle measuring elements arranged between the two outer measuring elements each have on their upper side a groove which extends from a stop web to the end of the measuring element and widens inwards, and on their undersides each have a bung which extends from a flat receiving area for a stop web of the measuring element below to the end of the measuring element and widens outwards.

[0020] The bungs and grooves connect the measuring elements to each other and simultaneously form a guide for extending and retracting the folding ruler. Additional bung grooves are provided in the bungs for arranging and accommodating locking elements. The measuring elements feature coordinated locking elements designed to lock and secure the measuring elements in the fully extended and fully retracted states.

[0021] In a preferred embodiment of the present invention, the tongue and groove joint is a dovetail joint. The outwardly widening tongues are dovetail-shaped, while the corresponding inwardly widening grooves are trapezoidal.

[0022] A further advantageous embodiment of the present invention provides that the tongue and groove connection is T-shaped, wherein the outwardly widening tongues are T-shaped and the corresponding inwardly widening grooves are inverted T-shaped.

[0023] In an advantageous embodiment for a folding measuring rod, the locking elements provided in the bung grooves comprise convexities located opposite one another on both sides and projecting into the interior of the bung groove in the front area of ​​the bung groove which is open and visible when the measuring elements are pulled apart.

[0024] Preferably, this arrangement of the locking elements is combined with additional curvatures, which also protrude on both sides, in the rear region of the bung groove lying in the pull-out direction, wherein the additional curvatures are combined with stop elements arranged on both sides and perpendicular to the pull-out direction, which have a stop surface oriented perpendicular to the pull-out direction.

[0025] Advantageously, the locking elements in the bung grooves interact with at least one corresponding locking element of an adjacent measuring element arranged in the inwardly widening grooves. The locking elements are designed to lock and secure the measuring elements in the fully extended and retracted states.

[0026] A preferred embodiment of the present measuring rod provides that the at least one corresponding locking element of the adjacent measuring element, which is arranged in the inwardly widening grooves, is a free-standing isosceles prism, wherein the prism is arranged centrally in the rear region of the groove lying in the extension direction, wherein the tip of the prism formed by the equal legs points in the extension direction and the locking elements are coordinated with one another in such a way that the flat side of the prism rests against the stop surfaces of the stop elements when the measuring element is completely pulled out and thus the prism locks between the stop elements and the curvatures.

[0027] The subject of an alternative, particularly preferred embodiment is a folding measuring rod according to the invention, in which the locking elements are permanent magnets integrated in the measuring elements, wherein, for example, a larger permanent magnet is firmly seated in a bore in the groove which widens towards the inside and projects beyond the bottom thereof into the front area of ​​the bung groove of the adjacent measuring element, while the second smaller permanent magnet is flush with a bore in the bung groove, wherein the permanent magnets are arranged in such a way that the larger permanent magnet comes to stand above the smaller permanent magnet after the measuring element has been pulled out and is fixed there due to the magnetic forces.

[0028] Preferably, in the above-described alternative embodiment of the locking elements as permanent magnets, the bung groove is delimited at both ends of the bung by holding webs, wherein the two permanent magnets are arranged in the immediate vicinity of the holding webs, so that when the measuring element is pulled out, the larger permanent magnet projecting into the bung groove is stopped by the holding web adjacent to the smaller permanent magnet, thus preventing unintentional removal of the measuring element in question from the folding measuring rod.

[0029] The proposed extendable folding rule is explained in detail below using selected examples and drawings. It is to be understood that these examples are by no means limiting, but merely serve to explain the basic principle of the present invention. DESCRIPTION OF THE DRAWINGS

[0030] The various exemplary features described above can be combined with one another according to the invention, as long as this is technically feasible. Further features, advantages, and embodiments of the invention will become apparent from the following description of the figures.

[0031] The figures used for explanation show: Fig. 1 an interrupted, perspective view of a partially exploded folding measuring rod in the view from above together with an exemplary, individual measuring element to be arranged inside the measuring rod package from the same perspective, Fig. 2 an interrupted, perspective view of a partially expanded folding measuring rod in the view from below together with an exemplary, individual measuring element to be arranged inside the measuring rod package from the same perspective, Fig. 3 a cross-section along the section plane S1-S2 Fig. 1, Fig. 4 a horizontal longitudinal section along the plane S3 Fig. 3, Fig. 5 an interrupted, perspective instruction drawing with two central measuring elements, Fig. 6 sectional drawings along the planes S4-S5 and S6-S7 from Fig. 5 and Fig. 7 a sectional drawing of a longitudinal section along the plane S8-S9.

[0032] Before the Fig. 1 and Fig. 2, it is necessary to point out one characteristic of measuring rod packages which can make a detailed description more difficult: namely, that they can generally be used on both sides. In the following description of the figures, a selected side was therefore arbitrarily defined as the top side, which then inevitably means that the opposite side is defined as the bottom side. However, this definition merely serves the purpose of enabling a clear and unambiguous description of the folding measuring rod 1 based on the figures. Of course, the designations could also have been interchanged, which would not change anything about the folding measuring rod 1 for the expert and user.Thus, the folding measuring stick 1 is preferably also scaled on both sides and can be used on both sides, wherein on the underside of the embodiments described below, a double scale is preferably provided, which enables the simultaneous use of the folding measuring stick 1 as a niche measuring stick.

[0033] The Fig. Figure 1 shows the top side 3 of a partially extended folding measuring rod 1 with a single measuring element 2 taken separately from the interior of the measuring rod package as an illustrative example. The folding measuring rod 1 and the individual measuring elements 2 are drawn interrupted due to their length in order to provide a compact overview. The individual measuring elements are connected to each other by a tongue and groove connection, which is not visible in the selected illustration and will be explained later using the Fig. 3 is explained in more detail. The uppermost measuring element 2 has an upper side 3 with a smooth surface on which the units of measurement and the scale are printed. For reasons of economy, only some of the units have been shown as examples for the entire measuring element 2. The scale was chosen so that the right-hand end of the uppermost measuring element 2 forms the zero point and the scale increases continuously to the left. In the present embodiment, a length of twenty-four centimeters was chosen for the individual measuring elements, so that for the fully extended folding measuring rod 1, a length of 2.04 m is obtained if, when each measuring element is pulled out, two by two centimeters are required for the mechanism for stable attachment and fixation to the adjacent measuring elements.

[0034] On the second measuring element 2 located underneath, a groove 8 is drawn on the upper side 3, which extends from a stop web 6 to the end of the measuring element 2, which in the Fig. 1 can be clearly seen in the individual measuring element 2 chosen as an example. The individual measuring element 2 is also drawn in broken lines and, for economic reasons, a scale has been omitted entirely. This design with the groove 8 continues through the entire folding rule 1, which in the selected example consists of a total of ten measuring elements 2 and thus corresponds to the usual folding rules with a length of two meters. Also worth mentioning with the individual measuring element 2 is a prism 14, which protrudes from the bottom of the groove 8 at the end thereof and points with its tip in the direction of extension. The exact positioning of the prism 14 in the groove 8 will be explained later using the Fig. 3, in which the cutting plane is shown graphically, which is formed by the Fig. 1 drawn section lines S1 and S2.

[0035] The Fig. 2 is the counterpart to Fig. 1 and shows the view of the underside 4 of a partially extended measuring rod 1, also with a single measuring element 2 taken out separately from the inside of the measuring rod package as an illustrative example. At this point, it should be pointed out again that the measuring rod 1 can be used on both sides, whereby in the Fig. 2, the lowest measuring element 2 is now pulled out and forms the beginning of the measuring process. The underside 4 of the lowest measuring element 2 also has a smooth surface, which is printed with a scale. Analogous to Fig. 1, interruptions in the drawings were chosen to allow a compact representation, and for economic reasons, the scaling was omitted in whole or in part. On the underside 4, the right end of the lowest measuring element 2 is also intended to form the zero point, although the scaling is now selected so that the folding ruler 1 can also be used as a niche measuring element. For this purpose, the measuring units on the subsequent measuring elements 2 are arranged in reverse and, for example, on the second measuring element 2, when this is fully extended, begin with 44 centimeters and end at 24 centimeters. With this arrangement, the niche measurement can then be read at the transition point from the lower to the next higher measuring element 2. For example, the Fig. The arrangement of the folding ruler 1 shown in Figure 2, with two fully extended measuring elements 2 and a third slightly extended measuring element 2, would result in a niche measurement of 47 centimeters. If only the bottom two measuring elements 2 were extended, a niche measurement of 44 centimeters could be read.

[0036] A particularly preferred embodiment of the folding ruler 1 provides that, for example, on the Fig. 2, a double scale is provided, whereby then, for example, on the second lowest measuring element 2, the units of measurement would not only be entered in reverse, but also a continuous scale would be provided, which would then, for example, be located on the outer edge of the underside 4 of the measuring element 2. In this way, the back of the folding measuring element 1 could be used not only as a niche measure, but also for normal length measurement. A comparable double scale can of course also be used for the top side 3 of the Fig. 1, which would further simplify the measurement as a whole, since the user would no longer have to pay attention to which side of the measuring stick 1 he is using. This double scaling on both sides thus corresponds to a particularly advantageous embodiment of the measuring stick 1, which, however, is not shown in a figure due to the great graphic effort, whereby the applicants have also assumed that the person skilled in the art will be able to identify the Fig. 1 and Fig. 2 can easily imagine a folding ruler 1 with a double scale on both sides.

[0037] The second lowest measuring element 2 and of course all middle measuring elements 2 have on their undersides 4, which can be seen in the Fig. 2, a dovetail-shaped, outwardly widening bung 7 is shown, which, starting from a flat receiving area 5 for a stop web 6 of the measuring element 2 located above, extends in the longitudinal direction continuously to the end of the measuring element 2. A bung groove 9 is arranged in the bung 7, which is open towards the receiving area 5 for the holding web 6 of the measuring element 2 located above, while it is delimited at the other end of the bung 7 by a holding web 19. Locking elements 10, 11, 12 are arranged inside the bung groove 9 itself, with two curvatures 10 located opposite one another on both sides and projecting into the interior of the bung groove 9 in the front area of ​​the bung groove 9, which is open when pulled apart.Similar curvatures 11, which also protrude into the interior of the bung groove 9, are also provided in the rear area of ​​the bung groove 9 lying in the pull-out direction, wherein the curvatures 11 in the rear area are combined with stop elements 12 arranged on both sides, each having a stop surface 13 aligned perpendicular to the pull-out direction. The interaction of the locking elements and the locking mechanism itself will be described later with the aid of the . Fig. 4 explained.

[0038] Subject of the Fig. 3 is a section of a section line S1 and S2 in Fig. 1 spanned section plane through a folding ruler 1, in which a measuring element 2 is completely grasped. In this illustration, the trapezoidal groove 8 formed on the upper side 3 of the measuring element 2 can be seen, which is in operative connection with the dovetail-shaped bung 7 formed on the underside 4 and forms the tongue and groove connection between the individual measuring elements 2. The cross section passes through the locking element 14 designed as a prism, which is arranged centrally on the base in the groove 8 and, in the collapsed state of the folding ruler 1 shown here, projects into the bung groove 9 in order to enter into operative connection with the locking elements 10, 11, 12 provided for this purpose. This locking mechanism is described in the following Fig. 4, which shows a horizontal section in the longitudinal direction through a measuring element 2 at the level of the Fig. 3 shows the section line S3.

[0039] In the Fig. 4 is a horizontally aligned longitudinal section through a measuring element 2 in the section plane S3 of Fig. 3. The section plane S3 was selected in such a way that the locking elements 10, 11, 12 and 14 acting in the tongue groove 9 are recorded in their interaction. It should be noted that the longitudinal section, again drawn interrupted, depicts temporally different states of the folding ruler 1 on both sides of the interruption, which makes it possible to illustrate the functioning of the locking elements 10, 11, 12 and 14 in the fully pushed together and fully pulled apart state in one drawing. For the longitudinal section, a perspective with a view of the underside 4 has been selected, which allows a view into the tongue groove 9. In the left part of the Fig. 4 shows the position of the locking elements 10 and 14 in the fully collapsed state of the folding measuring rod 1, wherein the locking element 14 is pushed behind the locking curvatures 10 and fixed there. At the same time, the stop bar 6 of the adjacent measuring element 2 positioned above it, which is positioned on the receiving area 5, rests against the bung 7, which corresponds to the fully collapsed and closed state of the folding measuring rod 1. In the present section through the measuring element 2, the stop bar 6 of a neighboring measuring element 2 cannot be shown. For a better understanding, however, an additional look back at the Fig. 1 and Fig. 2 is recommended, whereby the observer must imagine that the separate measuring element 2 consists of Fig. 1 is turned over and with its locking element 14 into the bung groove 9 of the separate measuring element 2 from Fig. 2 is introduced. At the same time, the tongue and groove connection between the two measuring elements 2 is realized by the tongue 7 of the measuring element 2 being Fig. 2 into the groove 8 of the measuring element 2 Fig. 1 is introduced.

[0040] The right part of the interrupted Fig. 4 shows the position of the locking elements 11 and 14 when the folding ruler 1 is fully extended. The locking element 14 is displaced from its rest position behind the locking curvatures 10 into the locking position between the locking elements 11 and 12 at the other end of the bung groove 9, with the prism 14 resting with its rear side 16 against the stop surfaces 13 of the stop elements 12, blocking further withdrawal and removal of the measuring element 2 from the folding ruler 1. From this position, the prism 14, with its tip 15 first, can be pushed back over the locking curvatures 11 into the bung groove 9 into the rest position behind the locking curvatures 10.

[0041] The Fig. Figure 5 is a perspective instruction drawing with two middle measuring elements 2, in which permanent magnets 17, 18 are provided as alternative locking elements. The measuring elements 2, shown in broken lines, have on their upper side 3 a trapezoidal, inwardly widening groove 8, from which a permanent magnet 17 protrudes in the upper measuring element 2. The permanent magnet 17 extends from the bung groove 9 on the underside 4 beyond the bottom of the groove 8 to the upper side 3. On its underside 4, the lower measuring element 2 has a bung 7 corresponding to the trapezoidal groove 8, in which a bung groove 9 is formed, delimited at both ends by retaining webs 19.Permanent magnets 17, 18 are provided as locking elements in the bung groove 9, adjacent to the holding webs 19 in the base of the bung groove 9. The locking element 17 of the upper measuring element 2 interacts with the analogous permanent magnet 17 of the lower measuring element 2 when the measuring elements 2 are brought together in the collapsed state of the folding measuring rod 1, whereby the measuring elements 2 are fixed in this position. The magnetic force is selected such that the folding measuring rod 1 holds together well in the collapsed state, but the measuring elements 2 can be pulled out with little force. After a measuring element 2 has been completely pulled out of the stack, the permanent magnet protruding into the bung groove 9 is positioned over the permanent magnet 18 of the adjacent measuring element 2, which is flush with the bung groove 9, whereby the measuring element 2 is fixed in this position.Further withdrawal or removal of a measuring element 2 from the package is prevented by the retaining web 19, against which the permanent magnet 17 projecting into the bung groove 9 strikes when withdrawn. The section lines S4, S5, S6, and S7 indicate section planes, the sections of which are shown in the following. Fig. 6 are shown graphically.

[0042] The left part of the Fig. 6 shows a cross-section of the folding measuring rod 1 in the plane S4-S5 with three measuring elements 2 from Fig. 5, while the right part of the figure also shows the cross section in the plane S6-S7 with three measuring elements Fig. 5. These sections are used to explain the installation conditions for the magnets 17, 18. The small permanent magnets 18 are embedded flush in the bottom of the bung groove 9, while the large permanent magnets 17 are located in a through-hole in the measuring element 2, starting from the bottom of the bung groove 9, where they are embedded flush, and extending beyond the bottom of the groove 8, so that in the assembled folding measuring rod 1 they protrude freely into the bung groove 9 of the adjacent measuring element 2. Two auxiliary lines H1 and H2 are also drawn, which will be referred to in the following Fig. 7 is used to show the positioning of the magnets 17, 18 in a longitudinal section.

[0043] In the Fig. Figure 7 shows the arrangement of the permanent magnets 17, 18 in the upper three measuring elements 2 of a measuring rod 1 using a longitudinal section along the section plane S8-S9. To be able to classify the positioning of the magnets in the measuring element package more precisely, auxiliary lines H1 and H2 were introduced, whereby auxiliary line H1 corresponds to the level of the bottom of the groove 8 and auxiliary line H2 to the bottom of the bung groove 9. Compared to Fig. 6 was in the Fig. 7 the folding ruler is rotated so that the view now falls on the upper side 3 of the uppermost measuring element 2 of a folding ruler 1. The interrupted sectional view shows the positions of the locking magnets 17, 18 when the folding ruler 1 is pushed together, with two small magnets 18 being flush with the bung groove 9 on the underside 4 of the uppermost measuring element 2. The level of the bottom of the bung groove 9 is marked by the auxiliary line H2. In the second uppermost measuring element 2, on the right-hand side of the interrupted section, a large continuous magnet 17 can be seen, which extends from the bottom of the bung groove 9 of the second measuring element 2 over the bottom of the groove 8 into the bung groove 9 of the first measuring element 2, where it interacts with the small magnet 18 of the upper measuring element 2. The two upper measuring elements 2 are thus fixed to one another.When the lower measuring element 2 is completely pulled out to the left, the large magnet 18 interacts with the small magnet 18 on the right, thus fixing the extended position. Pulling it out beyond this point is prevented by the retaining bar 19, against which the permanent magnet 17 abuts in this position.

[0044] As already mentioned at the beginning of the description of the figures, the above-described embodiments of the present invention are selected examples that are in no way to be considered as limitations, but merely serve to explain the basic principle of the present invention. The essential features of the folding ruler 1 according to the invention are that the measuring elements 2 are connected to one another via a tongue and groove connection and have a specific arrangement of locking elements, with which the fully retracted and fully extended state of the folding ruler 1 can be fixed.

[0045] The tongue and groove connection can also be realized with T-shaped connecting elements, which can be combined with locking elements in the same way as in the figures described above. In addition, other geometric configurations of the tongue and groove connection are conceivable, which will be obvious to the person skilled in the art.

[0046] It is also considered essential to the invention that a special design of the bung 7 with a bung groove 9 is provided, which enables the interaction between the locking elements, wherein in addition to the embodiments, designs and arrangements of the locking elements described above as examples, a large number of further combinations and variations are conceivable, which will also be obvious to the person skilled in the art and are thus covered by the claims formulated below. LIST OF REFERENCE SYMBOLS 1 folding ruler 2 measuring elements 3 Top side (measuring element) 4 Bottom (measuring element) 5 Mounting area for stop bar 6 Stop bar 7 bunging 8 grooves 9 tongue and groove 10 locking element (front curvature) 11 Locking element (rear curvature) 12 stop element 13 Stop surface 14 locking element, prism 15 Tip (prism) 16 Back (prism) 17 Permanent magnet (large) 18 Permanent magnet (small) 19 Stop bridge S1 section line ( Fig. 1) S2 section line ( Fig. 1) S3 section line ( Fig. 3) S4 cutting line ( Fig. 5) S5 cutting line ( Fig. 5) S6 cutting line ( Fig. 5) S7 section line ( Fig. 5) S8 cutting line ( Fig. 7) S9 section line ( Fig. 7) H1 auxiliary line ( Fig. 6, Fig. 7) H2 auxiliary line ( Fig. 6, Fig. 7)

Claims

[1] Extendable articulated measuring rod (1) constructed from several measuring elements arranged one above the other, wherein the individual measuring elements (2) are connected to one another via a tongue and groove connection, wherein - the uppermost measuring element (2) has a smooth upper side (3) and on its underside (4) has a continuous outwardly widening bung (7) extending from a flat receiving area (5) for a stop web (6) of the underlying measuring element (2) to the end of the measuring element (2) in the longitudinal direction, - as a counterpart, the lowest measuring element (2) has a smooth underside (4) and on its upper side (3) has a groove (8) extending from a stop web (6) to the end of the measuring element and widening inwards, - the middle measuring elements (2) arranged between the two outer measuring elements (2) each have on their upper sides (3) a groove (8) extending from a stop web (6) to the end of the measuring element (2) and widening inwards, and on their lower sides (4) each have a bung (7) extending from a flat receiving area (5) for a stop web (6) of the underlying measuring element (2) to the end of the measuring element (2) and widening outwards, - the bungs (7) and the grooves (8) are designed as a connection between the measuring elements (2) and at the same time as a guide for pulling apart and pushing together the articulated measuring rod (1), - additional longitudinally extending bung grooves (9) are arranged in the bungs (7) for arranging and receiving locking elements, - wherein the measuring elements (2) have matching locking elements provided for locking and fixing the measuring elements (2) in the fully extended and fully retracted state, characterized by that the locking elements in the measuring elements (2) are permanent magnets (17, 18) integrated, wherein a larger permanent magnet (17) sits firmly in a bore in the inwardly widening groove (8) and projects beyond the bottom thereof into the bung groove (9) of the adjacent measuring element (2), while a smaller permanent magnet (18) is flush with a bore in the bung groove (9), wherein the permanent magnets (17, 18) are arranged such that the larger permanent magnet (17) comes to stand above the smaller permanent magnet (18) after the measuring element (2) has been pulled out and is fixed in this position due to the magnetic forces. [2] Folding measuring stick according to claim 1, characterized bythat the tongue and groove connection is designed as a dovetail connection, wherein the outwardly widening tongues (7) are dovetail-shaped and the corresponding inwardly widening grooves (8) are trapezoidal. [3] Folding measuring stick (1) according to claim 1, characterized by that the tongue and groove connection is T-shaped, wherein the outwardly widening tongues (7) are T-shaped and the corresponding inwardly widening grooves (8) are inverted T-shaped. [4] Folding measuring stick (1) according to one of claims 1 to 3, characterized bythat the bung groove (9) is delimited at both ends of the bung by holding webs (19), wherein the two permanent magnets (17, 18) are arranged in the immediate vicinity of the holding webs (19), so that when the measuring element (2) is pulled out, the larger permanent magnet (17) projecting into the bung groove (9) is stopped by the holding web (19) adjacent to the smaller permanent magnet (18), thus preventing unintentional removal of the measuring element (2) in question from the folding measuring rod (1).

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