DE29617085U1 - Platform scale - Google Patents

Description

Description

Title: Platform scale

The invention relates to a platform scale whose weighing frame consists mainly of aluminum profiles cut to length according to the weighing task or the installation dimensions, corner nodes for fastening commercially available load cells and a structure adapted to the weighing task.

Platform scales are used to weigh all kinds of goods and are often installed in pits, so that access with industrial trucks is made easier due to the lack of level differences.

Older, mechanical spring, inclination or illuminated image scales are increasingly being installed in companies. Due to the different technical structure of these scales with lever transmissions in the scale frames, today's platform scales from well-known manufacturers do not fit into the existing pits when replacements are required due to their different dimensions. In this case, either a platform scale in a special size or costly structural changes to the pit are required.

Furthermore, platform scales are often installed in conveyors, roller conveyors or filling stations, the dimensions of which do not match the catalog dimensions of well-known platform scale manufacturers. In this case, too, complex custom-made products must be manufactured.

There are also goods to be weighed that have very small masses in relation to their volume (foam, bed feathers), so that a large platform dimension is necessary for a small weighing capacity and a correspondingly fine division of the scale. Such scales are not available on the market due to a lack of quantities.

Platform scales of the well-known type are designed with weighing frames as cast or welded constructions, which are subsequently machined and painted. Due to the long construction and set-up times, custom-made products in terms of size and weighing capacity can only be realized with corresponding effort.

The aim of the invention is to create a platform scale whose weighing frame can be manufactured quickly, flexibly and without the use of depreciation-intensive operating resources in almost any size and weighing capacity using standardized components. In addition, adaptation to the environment with regard to the weighing task, as well as the installation of covers, transport rollers, conveyors, etc., should be easy to carry out.

This object is achieved according to the invention in that aluminum profiles are cut to length according to the required dimensions of the weighing frame. In the corner areas, corner nodes are screwed to the aluminum profiles in a form-fitting and force-fitting manner, which have fastening threads for mounting commercially available load cells.

By arranging the load cells directly in the corner area of the weighing frame, on the one hand, the weighing frame is prevented from tipping up when a forklift truck drives onto it, as there is practically no tipping moment. On the other hand, the calibration officer can easily check whether the content of the installed load cells corresponds to the type approval of the scale.

In addition, the design of the corner nodes and thus the position of the load cells next to the aluminum profiles results in a relatively low installation height.

Press tools for aluminum profiles can be manufactured inexpensively thanks to erosion technology and can be adapted to the task with almost any imaginable shape. The inventive shape allows the assembly of covers, belt conveyors, containers and supporting structures using T-slots for common connecting elements on all sides of the profile without the need for welding or drilling. This eliminates the possibility of cables being destroyed by the rotating drill or the load cells being destroyed by overflowing welding currents.

The variation in the shape also allows the moment of inertia of the profile to be adapted to the expected load, which leads to weight savings and thus lower material costs.

A further advantage is that, due to the use of anodized aluminum or galvanized steel parts, a protective coating is not required.

A preferred embodiment of the invention is explained in more detail by the drawings and the following description. They show:

Fig. 1: Platform scale with weighing frame according to the invention in plan view

Fig.2: an enlarged section through the corner area according to Fig. 1 in the direction
of the arrows I

Fig.3: an enlarged view of the corner area of Fig. 1 in the direction of arrows II

Fig. 1 shows a top view of the platform scale according to the invention as shown in Fig. 1. The structure of the scale frame made of aluminum profiles (1) can be seen and in the corner areas the arrangement of the corner nodes (2) for holding the load cells. The measuring sensors, shown as shear force load cells (5) including the load cell feet (7), emit a changed measuring signal when the scale is loaded by unspecified strain gauges. The measured values are supplied to a junction box (9) using connecting cables (8), then connected in parallel and adjusted to a display device.

Fig. 2 shows the corner area of the platform scale as an enlarged section in the direction of arrows I. The corner nodes (2) for fastening the load cells (5) each have two raised, trapezoidal profiles (10) on the screwing surfaces, which engage in the grooves (3) of the aluminum profile (1) for a positive connection. Using inserted hexagon nuts (11), the profile (1) and corner nodes (2) are connected to one another by the screws (12) in such a way that the flanks of the interlocking profiles (10) exclude undesirable play and introduce the torques from the supporting forces of the load cells (5) into the aluminum profile (1) in a defined manner. To further stiffen the connection, the profiles (1) and corner nodes (2) are additionally screwed together at the end faces of the profiles using self-tapping screws (17). For this purpose, the aluminium profile (1) has round material recesses (18) in the cross-section corresponding to the core diameter of thread-forming screws. Depending on the desired weighing capacity of the platform scale, commercially available load cells (5) are mounted, the connecting cables (8) of which

guided through the grooves (3) and fixed by means of a clip (13). The depth of the grooves (3) is designed in such a way that the space remaining after the corner nodes (2) have been installed has a sufficiently large cross-section for the connection cables (8) to be fed through. A threaded pin (6) adjusted to the load capacity of the load cells and fixed by means of a screw lock serves to protect the load cells (5) from overloading. A cover plate (14) with a thickness appropriate to the load is attached to the top of the weighing frame using countersunk screws (15) and hexagon nuts (11). To make installation easier, slotted nuts made of flat profile can also be used instead of the nuts (11), which can be fixed in position.

Fig. 3 shows an enlarged view of the corner area of the platform scale according to Fig. 1 in the direction of arrows II. Here, commercially available transport rollers (16) are mounted instead of the cover plate as a further embodiment.

The invention is not limited to the embodiments shown and described, but changes and additions are possible without departing from the scope of the invention. For example, the corner nodes (2) can be designed at a 60° angle, so that a triangular weighing frame is created using 3 aluminum profiles (1). This means that only 3 load cells are necessary, which on the one hand leads to a reduction in costs, and on the other hand is also the better solution in terms of weighing, for example, round containers due to the defined support forces of the load cells.

Instead of the shear force load cells mentioned above, bending beam load cells as well as parallel guided load cells with the corresponding force introduction elements are also possible.

List of reference numbers

1. Aluminium profile

2. Corner knot

3- trapezoidal groove of the aluminum profile

4. T-shaped groove of the aluminum profile

5. Load cell

6. Top load screw

7. Load cell base

8. Connection cable

9. Junction box

10. trapezoidal profiles of the corner node

11. Hexagon nut

12. Screw

13. Fastening clip

14. Cover plate

15. Countersunk screw

16. Transport roller

17. self-tapping screw

18. round material recess of the aluminum profile

Claims (3)

Protection claims 1. Platform scale with load cells arranged in the corner area of a weighing frame, characterized in that the weighing frame has aluminum profiles (1) and corner nodes (2) which are connected to one another by means of an interlocking mold and counter-mold both in a form-fitting manner and in a force-fitting manner by screwing. 2. Platform scale according to claim 1, characterized in that the aluminum profile (1) has trapezoidal grooves (3) incorporated in accordance with the shape of the corner nodes (2), T-shaped grooves (4) on all sides corresponding to the wrench size of hexagon nuts and round material recesses (18) corresponding to the core diameter of thread-forming screws. 3. Platform scale according to claim 1, characterized in that the design of the corner nodes (2) enables a position of the load cells (5) directly in the corner area of the scale frame and laterally next to the aluminum profiles (1), has profiles (10) machined in accordance with the shape of the grooves (3) of the aluminum profile (1), threaded holes for fastening commercially available load cells (5) and a threaded hole for mounting an overload screw (6).