The invention relates to a draft shield for a precision balance, which surrounds a weighing chamber, having at least one side panel and a suspension guide for the side panel, wherein the suspension guide comprises a guide rail and a holding device for the side panel, wherein the holding device is displaceably mounted in the guide rail, wherein the holding device has a seating for the side panel and at least one guide element which engages in the guide rail and is displaceably mounted therein, wherein the side panel is held with an upper edge in the holding device of the suspension guide. The invention also relates to a suspension guide for a side panel of such a draft shield.
It is commonly known to mount a draft shield on a precision balance, said draft shield surrounding a space above the weighing dish of the balance. Examples of a draft shield of this type are disclosed by DE 94 07 984 U1 and EP 1 195 585 A1. The draft shield has the task of preventing air movements, electrostatic attractive forces or thermal radiation from influencing the weighing process. In order to be able to place an object to be weighed on the weighing dish, a draft shield of this type has a side panel which can be displaced between a closed position and an open position.
A further draft shield is disclosed in EP 2 251 657 A1. This has guidance means, for example, guide rails for the side panel in which the side panel is mounted such that it is pressed with the lower edge against the bottom of the draft shield. However, the side panels must be exactly oriented before being suspended in the guidance means.
From U.S. Pat. No. 3,975,862, sliding doors are known which are mounted such that they support one another and, despite the lack of floor-side guide rails, remain in the vertical position and do not snag one another.
In order to clean the draft shield or to gain unhindered access to the weighing dish, it is desirable to be able to demount this panel completely, preferably without the use of tools. At the same time, in the closed position, the side panel must close the weighing chamber completely so that the effects of environmental influences on the weighing process are reliably prevented.
It is an object of the invention to provide a suspension guide for a side panel of a draft shield of a precision balance which enables simple demounting and mounting of the side panel, but also enables reliable guidance and tight closing of the side panel. It is a further object of the invention to provide a draft shield for a precision balance which is demountable easily and without tools and which ensures reliable sealing of the weighing chamber.
In order to achieve these objects, according to one formulation of the invention, a draft shield of the type mentioned in the introduction is provided, in which the guide element is arranged outside a plane which is defined by the seating of the side panel and in which the holding device is mounted in the guide rail pivotable about a contact line between the guide element and the guide rail, wherein the plane of the side panel in relation to the weighing chamber is arranged offset outwardly relative to the guide rail.
The side panel of the draft shield can be fastened in the seating of the holding device, wherein the side panel is arranged in the plane defined by the seating. Since the guide element is arranged outside the plane defined by the seating and the side panel, the guide element is situated laterally offset relative to the side panel. Thus the guide element is arranged outside the center of gravity of an assembly consisting of the holding device and the side panel. When this assembly is hooked into the guide rail in which it is mounted displaceable in the longitudinal direction, this assembly has the tendency to tilt inwardly about the contact line of the guide element on the guide rail until the center of gravity is situated below the contact line.
Preferably provided on the draft shield or on the precision balance is a contact surface against which the lower edge of the side panel comes into contact or is pressed due to this tilting tendency. The contact surface is preferably configured such that the side panel makes contact areally with the lower edge so that the lower edge is tightly closed by the contact of the side panel against the contact surface. Therefore, due to the contact surface, which preferably extends parallel to the guide rail, a tight closure at the lower edge of the side panel is possible without additional guides or sealing elements being required. The sealing takes place automatically due to gravity, by which the lower edge is pressed against the contact surface.
Since the contact surface preferably extends in the direction of the guide rail, the contact surface can also serve as a guide for the side panel in order to guide the lower edge of the side panel between the open and closed positions. An arrangement of a further guide rail at the lower edge of the side panel is not necessary. A planar contact surface on which the side panel can make contact is thus entirely sufficient as a guide and also for tight contact.
Since the assembly of the side panel and the holding device only makes contact at the lower edge of the draft shield with the contact surface and is not held by the lower edge, easy demounting of the side panel is also possible. For this purpose, the side panel must only be unhooked from the suspension guide arranged at the upper edge, for example, in that it is lifted upwardly out of the guide rail. The mounting of the side panel is also substantially facilitated since it is only required to hook the holding device into the guide rail. Additional mounting or threading of the lower edge of the side panel into a lower guide is not necessary. Due to the tilting tendency, the side panel comes automatically into contact with the contact surface so that orientation of the lower edge of the side panel is not necessary.
Through this arrangement of the guide elements, it is thus ensured that they are arranged outside the center of gravity of the assembly of holding device and side panel, so that after hooking into the guide rail, this assembly has a tendency to tilt against a contact surface. Preferably, a contact surface is provided on the draft shield, against which the lower edge of the side panel can lie, wherein the contact surface is arranged parallel to the plane of the side panel. Preferably, the contact surface is arranged such that the plane of the side panel in the mounted state of the side panel extends substantially vertically. The contact surface serves both as a stop for the side panel, in order to seal the lower edge of the side panel, and also as a guide surface along which the side panel can slide in order to displace it between the closed position and the open position.
The stop surface is arranged, for example, offset in relation to a vertical through the guide rail in the direction toward the side panel, so that the side panel is pressed against the stop surface by gravity. Thus, a pressing force of the side panel against the contact surface is ensured, by which a reliable sealing of the lower edge of the side panel is ensured.
Even when the side panel is pressed against the contact surface due to the center of gravity being offset relative to the contact line, a guide projection which holds the lower edge of the side panel against the contact surface can additionally be provided.
Preferably, the draft shield has a cover which closes the weighing chamber upwardly. The guide rails can be provided, for example, on the cover. The cover can, for example, also be constructed multi-part so that, for example, the cover element is formed by a part of the cover.
In order to prevent influencing of the measurement result by electrostatic charging of the draft shield, the side panel and/or the suspension guide are configured to be electrically conductive and/or coated and are electrically coupled to one another so that electrostatic charges can be conducted away.
According to a further formulation of the invention, a suspension guide for a side panel of a draft shield is provided, having a guide rail and a holding device for the side panel, displaceably mounted in the guide rail, wherein the holding device has a seating for the side panel and at least one guide element which engages in the guide rail and is displaceably mounted therein. According to this formulation, the guide element is arranged outside a plane which is defined by the seating of the side panel and the holding device is mounted in the guide rail pivotable about the contact line between the guide element and the guide rail.
In order to enable easy mounting and demounting of the side panel, the guide rail has, for example, an upwardly open groove into which the at least one guide element can easily be hooked in from above. The holding device with the side panel can thus easily be removed upwardly from the guide rail. Therefore, easy demounting is possible without the need for additional tools. At the same time, secure guidance of the holding device and thus of the side panel is ensured, since the guide elements cannot tilt laterally out of the guide rail.
The guide elements of the holding device can be, for example, rollers which roll along on the guide rail. With the rollers, a lower resistance is possible during displacement of the side panel or the holding device between the open position and the closed position. In addition, due to the form of the rollers, a very narrow contact line, about which the holding device can tilt, is possible. With suitable bearings for the rollers, for example ball bearings, the rolling resistance can be further reduced.
For demounting the side panel, the holding device can preferably be removed upwardly out of the guide rail. In order to prevent unintentional demounting of the side panel, for example, a cover element which covers the guide rail is provided. This cover element is configured such that it covers the guide rail and the guide element in a holding position so that the guide element cannot be removed from the guide rail. Only when the cover element has been removed or moved into a releasing position in which the guide rail is no longer covered can the guide element be removed from the guide rail.
Further advantages and features are disclosed in the following description making reference to the accompanying drawings. In the drawings:
The draft shield 12 has a front panel 18, a rear wall 20 and two mutually opposed side walls 22. In addition, a cover 24 is provided which closes the draft shield 12 upwardly. The rear wall 20 is firmly connected to the weighing device 14 and forms a support for the cover 24. The side walls 22 each have a side panel 26 which are respectively displaceable between a closed and an open position (
In the closed position shown in
In order to be able to clean the draft shield 12 and the precision balance 10 easily, the side panels 26, the front panel 18, parts of the cover 24 and the weighing chamber bottom 34 are configured demountable, as will now be described. In particular, all the parts can be demounted without tools.
The demountable components of the draft shield 12 and the precision balance 10 will now be described.
As shown in
As shown in
Additionally, provided on the surfaces of the guide rails 38 facing one another are slide rails 46 extending in the longitudinal direction L of the guide rails 38. A cover panel 48 (see
The slide rails 46 are made preferably of plastics. The remainder of the support frame 36 can be made of metal, for example aluminum, or also of plastics. The cover panel 48 is made, for example, of glass and preferably has an electrically conductive coating. The fact that the slide rails 46 are made of plastics reliably prevents scratching of the cover panel 48. In order to prevent electrostatic charging of the cover panel 48, electrical conductors 52, for example carbon brushes, are provided in the rear region of the slide rails 46 on the support frame 36, wherein the brushes lie against the cover panel 48 and connect the cover panel electrically to the support frame 36.
In order to prevent electrostatic charging of the cover 24, all the parts of the cover 24 can either be configured electrically conductive or coated so that electric charges can be conducted away.
Similarly, the front panel 18, the side panels 22 and all the further parts of the draft shield 12 or the precision balance 10 can be configured electrically conductive and/or coated and electrically connected to one another so that electrostatic charging of individual parts, in particular the panel, is reliably prevented.
The cover 24 also has a cover element 54 which, as described below, is pivotable at one edge 56 of the cover 24, here the rear edge 56, between a holding position (
Since the bearing elements 62 are configured resilient in the longitudinal direction L, the whole cover element 54 can be displaced to a limited extent in the direction toward the bearing 60, wherein the cover element is loaded by the elastically yielding bearing elements 62 in the direction toward a second edge 68, here the front edge 68 of the support frame 36.
In order to hold the cover 24 in the closed holding position (
As shown in
The holding elements 72, 74 are thus released, for example, by a pressure on the front edge of the cover element 54, by which the cover element is displaced toward the bearing 60. Subsequently, the cover element 54 is moved by the spring elements 58 into the releasing position.
Even if no spring elements 58 are provided, it is easily possible to release the holding elements 72, 74 and to move the cover element into the releasing position. In order to release the holding elements 72, 74, pressure on the front edge 70 is needed. Following the release of the holding elements, the pressing direction must merely be changed and directed slightly upwardly. In the preferred embodiment, it is possible to select a pressing direction facing obliquely upwardly and in the longitudinal direction L, by which sufficient pressing force is applied to release the holding elements 72, 74 and the cover element 54 is subsequently moved into the releasing position without any change in the pressing direction. Thus, the cover element can be moved in a fluid movement from the holding position into the releasing position. Elaborate releasing of the holding elements 72, 74 is not necessary.
In the releasing position shown in
Furthermore, in this releasing position, as described below, the side panels 26 of the draft shield 12 can also be removed without tools.
As shown in
The suspension guides 78 are each formed by a guide rail 38 of the support frame 36 and by a holding device 84 on which the side panel 26 is held.
As shown in
Also provided on the holding device 84 are guide elements 92 formed by rollers, with which the holding device 84 can be mounted in the guide rails 38 displaceable in the longitudinal direction L.
The contact surface 82 is formed by a lateral border of the weighing chamber bottom 34, wherein the contact surface 82 extends in the longitudinal direction L and substantially vertically.
The guide rails 38 each have an upwardly open groove 94 into which the guide elements 92 can be hooked in vertically from above. The assembly made of the holding device 84 and the side panel 26 can be pivoted in this assembled state about the contact line 96 between the guide rails 38 and the guide elements 92.
As shown particularly in
Since the contact surface 82 extends in the longitudinal direction L, it also serves as a guide for the lower edge 80 of the side panel 26. Also provided on the contact surface 82 is a guide projection 97, which serves as a protective device in order to prevent lifting of the lower edge 80 of the side panel 26 from the contact surface 82. In normal operation of the precision balance 10 or of the draft shield 12, however, this guide projection 97 is not needed since the side panel 26 is pressed by gravity against the contact surface 82. Furthermore, a detent stop 99 is provided on the side surface 22 which holds the side panel 26 in the closed position.
Apart from the suspension guide 78 arranged at the upper edge 76 of the side panels 26, therefore, no additional complex mounting is needed at the lower edge 80.
Since the guide rails 38 are formed by upwardly open grooves 94, the side panels 26 can be easily removed vertically upwardly from the guide rails 38.
The mounting of the side panels 26 is also simplified since they have merely to be hooked into the guide rails 38 with the holding devices 84 or the guide elements 92. Due to gravity, the lower edges 80 automatically come into contact with the contact surfaces 82. Complex orientation of the lower edges 80 or feeding into a lower guide is not necessary.
In order to prevent the removal of the side panels 26 during normal operation of the draft shield 12, in the holding position, the cover element 54 covers the guide rails 38 vertically upwardly. The guide elements 92 thus cannot be removed from the guide rails. In order to be able to remove the side panels 26, it is necessary to move the cover element 54 into the releasing position in which the guide rails 38 are open vertically upwardly.
Irrespective of the configuration of the holding device or of the guide elements 92, it is merely necessary for the guide elements 92 to be arranged outside the plane formed by the side panel 26 or the seatings 86, so that the side panel can tilt about the contact line 96 between the guide rail 38 and the guide element 92 against the contact surface 82.
In order to prevent tilting in the plane of the side panels 26, a plurality of holding devices 84 can also be provided at a side panel 26.
As shown in
For this purpose, the weighing chamber bottom 34 has a weighing chamber bottom portion 98 and two side flanges 100. The side flanges 100 are disposed at opposing edges 102 of the weighing chamber bottom portion 98 and are arranged substantially perpendicular to the weighing chamber bottom portion 98 and parallel to one another.
Situated at the inner surfaces 104 facing one another are fastening devices 106 which in this embodiment are formed by locking elements. Provided on the housing of the weighing device 14 are substantially horizontally extending locking edges 108 on which the fastening devices 106 can engage.
The weighing chamber bottom 34 is placed vertically from above onto the weighing device 14, wherein the side flanges 100 encompass the housing on opposite sides. The weighing chamber bottom 34 is pushed onto the housing until the fastening devices 106 latch onto the locking edges 108. The side flanges 100 are configured elastically resilient so that they can give way during pushing onto the locking edges. If the fastening devices 106 are located behind the locking edges, the side flanges 100 are pressed resiliently against the housing, so that the fastening devices 106 latch onto the locking edges 108.
For demounting of the weighing chamber bottom 34, the side flanges 100 are pulled away laterally until the fastening devices 106 are released from the locking edges 108. Subsequently, the weighing chamber bottom 34 can be pulled upwardly from the housing (
As shown in
The weighing chamber bottom portion 98 is configured essentially planar (
The raised edges 110, 114 prevent liquids that find their way onto the weighing chamber bottom portion 98 from flowing out of the weighing chamber bottom 34 and flowing, for example, through the through opening 112 to the weighing mechanism and contaminating it.
As shown in
As
Thus, approximately all the parts of the draft shield 12 can be demounted without tools, so that easy cleaning of the draft shield 12 and the precision balance 10 and easy access to the weighing chamber 16 are possible.
In order to be able to clean the panels easily, that is, the cover panel 48, the side panel 26 and the front panel 18, components present on the panels, for example, handles 118 or the holding devices 84 can also be easily demounted, preferably without tools. In particular, the handles 118 can be easily latched on the panels, wherein tool-free release of this latching is possible.
Number | Date | Country | Kind |
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102013113006.2 | Nov 2013 | DE | national |
This is a Continuation of International Application PCT/EP2014/002812, which has an international filing date of Oct. 18, 2014, and the disclosure of which is incorporated in its entirety into the present Continuation by reference. The following disclosure is also based on and claims the benefit of and priority under 35 U.S.C. §119(a) to German Patent Application No. DE 10 2013 113 006.2, filed Nov. 25, 2013, which is also incorporated in its entirety into the present Continuation by reference.
Number | Date | Country | |
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Parent | PCT/EP2014/002812 | Oct 2014 | US |
Child | 15164274 | US |