CN216049972U

CN216049972U - Measuring device and fastening element for locking a housing cover on a device housing

Info

Publication number: CN216049972U
Application number: CN202120666280.5U
Authority: CN
Inventors: 托马斯·科普
Original assignee: Vega Grieshaber KG
Current assignee: Vega Grieshaber KG
Priority date: 2020-04-07
Filing date: 2021-04-01
Publication date: 2022-03-15
Anticipated expiration: 2031-04-01
Also published as: DE102020204517A1

Abstract

A fastening element made of plastic for locking a housing cover on a measuring device housing, which fastening element has an annular closed shape and is elastically deformed in a radial direction when the housing cover is placed on top until it snaps into a corresponding groove of the housing cover.

Description

Measuring device and fastening element for locking a housing cover on a device housing

Technical Field

The present invention relates to measuring device technology in industrial environments. In particular, the utility model relates to a plastic fastening element for locking a housing cover on a measuring device housing, a measuring device and the use of a fastening element.

Background

A measuring device, such as a pressure sensor, a level gauge or a limit level sensor, usually comprises a measuring device housing in which electronics are accommodated. The measuring device housing can be closed with a housing cover. For this purpose, a screw connection can be provided, for example.

SUMMERY OF THE UTILITY MODEL

It is an object of the present invention to provide a measuring device housing comprising an alternative closure.

A first aspect of the utility model relates to a fastening element, for example a plastic fastening element made of thermoplastic or of thermosetting plastic, or a fastening element made of metal having the same or similar mechanical properties as plastic, for locking a housing cover on a measuring device housing of a measuring device, in particular a measuring device housing of a measuring device for process automation in an industrial environment. In the following, the fastening element is referred to as plastic fastening element. However, the name may also include other materials.

The plastic fastening element has an annular closed shape which is configured to be inserted into a groove of the measuring device housing or (alternative) housing cover which extends in the circumferential direction. The plastic fastening element has in the circumferential direction wave-shaped, sawtooth-shaped or stepped portions which can elastically deform the plastic fastening element in the radial direction when the housing cover is pushed into or onto the measuring device housing to close the measuring device housing.

Thus, instead of a screw-in connection, an effective lid locking device can be provided.

The plastic fastening element makes a shock-resistant but easily mountable form-locking connection between the housing cover and the measuring device housing possible. The plastic fastening element may be pre-mounted in the housing or, alternatively, in the housing cover. In particular, the plastic fastening element can also be used for less stiff measuring device housing materials and/or housing cover materials (e.g. plastic).

According to one embodiment, the plastic fastening element consists of a wave-shaped, zigzag-shaped or stepped portion. No other shaped portion is provided. These portions may for example be triangular with rounded corners at the tip and at the connection areas between the respective triangles.

In particular, the plastic fastening element may be shaped such that it comprises more than three portions arranged at an angle of 120 ° to each other, or 10 to 20 or more (e.g. 12 to 18 or 15) wavy, serrated or stepped portions. Like a tripod, the minimum number is three. The maximum number depends on the diameter or circumference. The shape may be wavy or zigzag, but is not limited thereto. Preferably corrugated, since a larger cross-sectional area for the drawing force can thereby be provided. Sinusoidal designs are also contemplated.

In particular, each wavy or stepped portion has an internal lead-in chamfer which is arranged in the region of the smallest diameter of the fastening element.

According to one embodiment, each wavy, serrated or stepped portion comprises an internal or external lead-in chamfer

Or a chamfer (lose), which lead-in chamfer or chamfer is arranged in the region of the smallest diameter of the plastic fastening element. The inner chamfer is configured for pre-installation into a groove on the outer counterpart and the outer chamfer is configured for installation into a groove on the inner counterpart.

These internal lead-in ramps make it easier for the housing cover to press the respective portions of the plastic fastening element radially outward when the housing cover is pressed into or onto the measuring device housing.

Alternatively or additionally, each wavy, serrated or stepped portion may comprise an outer lead-in chamfer which is arranged in the region of the largest diameter of the plastic fastening element. It is particularly advantageous to insert the plastic fastening element into the groove of the housing cover before fastening the housing cover to the measuring device housing, so that the housing cover is pressed radially inward when the housing is pushed into or onto the measuring device housing by the cover.

Another aspect of the utility model relates to a measuring device comprising a measuring device housing comprising a first groove extending in a circumferential direction, a housing cover comprising a second groove extending in the circumferential direction, and a plastic fastening element as described above or below which is arranged partly in the first groove and partly in the second groove for locking the housing cover on the measuring device housing.

According to one embodiment, the measuring device is designed as a filling level measuring device (in particular a level radar measuring device), a pressure sensor or a limit level sensor.

Another aspect of the disclosure relates to the use of the plastic fastening element described above and below for locking a housing cover on a measuring device housing.

The embodiments will be described below with reference to the drawings. The illustrations in the drawings are schematic and not drawn to scale. If the same reference numbers are used in the following description of the figures, they refer to the same or similar elements.

Drawings

Fig. 1A shows a measuring device housing with a circular metal ring made of stainless steel.

Fig. 1B shows a cross-sectional view of the measuring device housing of fig. 1A with a housing cover inserted into the measuring device housing.

Fig. 2A shows a measuring device housing with a plastic fastening element.

Fig. 2B shows a view of the measuring device housing of fig. 2A.

FIG. 2C shows a view of the measurement device housing of FIG. 2A including an inserted housing cover.

Fig. 3 shows another cross-sectional view of the embodiment of fig. 2C.

Fig. 4 shows a portion of the cross-sectional view of fig. 3.

Fig. 5 shows a perspective view of a plastic fastening element according to an embodiment.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Fig. 1A shows a perspective view of a measuring device housing 103 of a measuring device for process automation in an industrial environment.

The term "process automation in an industrial environment" can be understood as a sub-field of technology, which encompasses measures for operating machines and equipment without human intervention. The goal of process automation is to automate the interaction of the various components of a plant in the chemical, food, pharmaceutical, petroleum, paper, cement, shipping or mining fields. For this purpose, a large number of sensors can be used, which are particularly suitable for the specific requirements of the process industry, such as mechanical stability, insensitivity to contaminants, extreme temperatures, extreme pressures, etc. The measurements of these sensors are typically transmitted to a control room where process parameters such as temperature, fill level, limit level, flow, pressure or density can be monitored and the settings of the entire plant can be altered manually or automatically.

One sub-field of process automation in an industrial environment relates to logistics automation. In the field of logistics automation, processes within buildings or individual logistics plants are automated by means of distance sensors and angle sensors. A typical application is a logistics automation system for the following fields: the field of baggage and cargo handling at airports, the field of traffic monitoring (toll collection systems), the field of commerce, the field of parcel delivery or building security (access control). Common to the previously listed examples is that each application side needs to combine presence detection with accurate measurement of the size and position of the object. For this purpose, sensors based on optical measurement methods by means of lasers, LEDs, 2D cameras or 3D cameras can be used, which detect distances according to the time of flight (ToF) principle.

Another sub-area of process automation in an industrial environment relates to factory/manufacturing automation. Examples of such applications are found in many industries, such as the automotive industry, food manufacturing industry, pharmaceutical industry or general packaging industry. The purpose of factory automation is to automate the production of goods by machines, production lines and/or robots, i.e. to run without human intervention. The sensor used here and the specific requirements for the measurement accuracy in detecting the position and size of the object are comparable to those in the above-described logistics automation example.

The measuring device housing 103 includes a groove 110 extending in the circumferential direction, and a circular metal ring made of stainless steel is inserted in the groove 110. The groove serves as a cover locking means, i.e., for locking the housing cover 104 as shown in fig. 1B.

The circular metal ring 200 or locking ring may be pressed radially outwards when the cap is mounted and then spring back when the cap is in its closed position.

Fig. 1B shows a sectional view of the measuring device housing of fig. 1A with the housing cover 104 placed thereon. It can be seen that the

respective grooves

110, 111 of the measuring device housing 103 and the housing cover 104 are at the same height, so that the circular metal ring 200 is partly located in the first groove and partly in the second groove in order to lock the housing cover.

For mounting reasons, the locking ring has only a slight overlap with the cap, i.e. the locking ring protrudes only relatively slightly inwards from the outer groove 110. This may result in that, when an impact is generated in the axial direction (i.e. in the upward direction in fig. 1B), the cap may jump out of the measuring device housing and the locking ring thus loses its function.

Fig. 2A shows a measuring device housing 103 in which a plastic fastening element 100 is arranged in a circumferential groove. A detailed view of the plastic fastening element 100 can be seen in fig. 5.

In particular, it can be seen that approximately half of the plastic fastening element protrudes inwardly from the circumferential groove of the housing, thereby ensuring effective locking of the housing cover.

Fig. 2B shows a view of the measurement device housing 103 of fig. 2A.

Fig. 2C shows a sectional view of the measuring device housing of fig. 2A with the housing cover 104 placed thereon. In particular, a relatively large overlap of the plastic fastening elements 100 can be seen, which reliably prevents the housing cover from slipping out of the measuring device housing.

Fig. 3 shows a further sectional view along the upper region of the measuring device 300.

Fig. 4 shows a detailed view of zone Z as shown in fig. 3.

In this case, in particular, a groove 111 of the housing cover 104 extending in the circumferential direction and an adjoining groove 110 of the measuring device housing 103, which also extends in the circumferential direction, can be seen in which the plastic fastening element 100 is located.

It can also be seen that the lead-in chamfer of the plastic fastening element 100

105, which is also shown in fig. 5.

Fig. 5 shows a perspective view of a plastic fastening element 100 having a corrugated portion 106 forming the annular closed shape of the plastic fastening element. The lead-in chamfer 105 is located in the region of the smallest diameter of the plastic fastening element. In the outer region, i.e. at the location where the plastic fastening elements each have the largest diameter (see region 106), a lead-in chamfer can also be provided.

The plastic fastening element is designed such that it can be centered in the housing and still have a good overlap at the latching position on the housing cover. An advantage of being centered in the housing is that the plastic fastening element cannot jump out or be extruded from the fastening position (i.e. out of the groove) when the cover is introduced into the housing. In addition, the centering insert on the cover can thus be smaller. The centering insert on the cap is, for example, a conical region 112 (see fig. 3).

In order to enable the plastic fastening element in the groove to transmit as large forces as possible, its outer contour is designed as a rectangular contour (because of the absence of burrs or because of manufacturability) in addition to a smaller radius. In order to be able to easily push the housing cover onto the fastening element, the inner region of the housing cover is designed with a sufficiently large chamfer (fasen) or bevel

To achieve a universal mounting, the plastic fastening element can be designed with a chamfer or lead-in chamfer on both sides.

The plastic fastening element 100 consists of a plurality of wave-shaped, triangular or stepped sections or arcs, whereby the plastic fastening element can be deflected radially outwards or inwards when a lid is placed on top.

The housing cover and the measuring device housing can consist, for example, of a relatively rigid material, in which case the plastic fastening element can also be made of a relatively rigid but elastic material. For example, the plastic fastening elements are made of Polyoxymethylene (POM) or generally of a thermoplastic material.

For example, the material is selected such that the plastic fastening element has sufficient elasticity to be able to place the housing cover thereon and not to damage the housing cover and the measuring device housing during mounting.

The plastic fastening element is deformed in two directions or types. By means of the lead-in ramps on the fastening elements, the force transmission of the housing cover in its axial direction causes a radial force towards the outer diameter of the fastening elements or the groove outer diameter of the housing. In addition, the plastic fastening element begins to bend in the axial direction of the cap with a certain force in this direction. These effects show that the installation places high demands on the choice of material. Improper materials may cause the fastening elements to break immediately.

If the plastic fastening element is mounted in its predetermined position in the measuring device housing and the measuring device cover, the cover rests with its surface on the undercut on the plastic fastening element and is therefore able to transmit and absorb more forces statically.

The housing cover can be designed such that the cover can no longer be opened without damage by locking the plastic fastening element on the measuring device housing. But rather damages the plastic fastening element when opening the housing cover.

The measuring device can be designed as a two-wire measuring device of 4/20mA, and also as a three-wire measuring device. It may also be designed to be wireless and self-contained, in which case the measuring device comprises, for example, a battery as an energy source.

For example, a plastic fastening element is first inserted into a groove of the measuring device housing. Due to its shape, it has a significant overlap with the housing cover (which means that it clearly projects into the groove of the cover), so that the form-locking elastic connection provides almost as good a force transmission as a metal locking ring.

In particular, plastic fastening elements, which are also made of this material group, are used for fastening measuring device housing covers (housing closures), for example made of thermoplastic. In particular, the plastic fastening element may be formed from a very elastic thermoplastic with moderate but sufficient strength.

In addition, it should be noted that "comprising" and "having" do not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. It should also be pointed out that characteristics or steps which have been described with reference to one of the above exemplary embodiments can also be used in combination with other characteristics or steps of other exemplary embodiments described above. Reference signs in the claims shall not be construed as limiting.

Cross Reference to Related Applications

This application claims priority from german patent application 102020204517.8 filed on 7/4/2020, which is incorporated herein by reference in its entirety.

Claims

1. A fastening element (100) for locking a housing cover (104) to a measuring device housing (103),

characterized in that the fastening element has an annular closed shape which is configured to be inserted into a groove of the measuring device housing or the housing cover extending in the circumferential direction,

wherein the fastening element has a wave-shaped, saw-toothed or stepped portion in the circumferential direction, which portion enables the fastening element to be elastically deformed in the radial direction when the housing cover is pushed into or onto the measuring device housing.

2. The fastening element (100) of claim 1,

characterized in that the fastening element consists of the wavy, serrated or stepped portion.

3. The fastening element (100) according to claim 1 or 2,

characterized in that the fastening element has more than three wave-shaped or step-shaped portions.

4. The fastening element (100) according to claim 1 or 2,

characterized in that the fastening element has 10 to 20 wave-shaped or step-shaped portions.

5. The fastening element (100) according to claim 1 or 2,

characterized in that the fastening element has 12 to 18 wave-shaped or step-shaped portions.

6. The fastening element (100) according to claim 1 or 2,

characterized in that each wavy or stepped portion has an internal lead-in chamfer (105), the internal lead-in chamfer (105) being arranged in the region of the smallest diameter of the fastening element.

7. The fastening element (100) according to claim 1 or 2,

characterized in that each wavy or stepped portion comprises an external lead-in chamfer which is arranged in the region of the maximum diameter (106) of the fastening element.

8. A measurement device (300), characterized by comprising:

a measuring device housing (103) having a first groove (110) extending in a circumferential direction;

a housing cover (104) including a second groove (111) extending in a circumferential direction;

the fastening element (100) according to any one of claims 1 to 7, which is arranged partially in the first groove and partially in the second groove to lock the housing cover on the measuring device housing.

9. The measurement device (300) of claim 8,

characterized in that the material of the measuring device housing (103) and the housing cover (104) is harder than the material of the fastening element (100).

10. The measuring device (300) according to claim 8 or 9, characterized by being designed as a filling level measuring device, a pressure sensor, a temperature measuring device or a limit level sensor.