Background of the Invention
The invention is related to a balance having a top mounted scale which is enclosed in a box-like structure to protect the scale from wind disturbances.
Similar balances are discloses in DE-OS No. 33 30 988. The box-like, or cuboid construction, which forms a weighing area around the balance scale protects the scale against the wind and consists, according to the state of the art, of a metallic carrying framework into which a front pane is set in a fixed manner and in which side glass sliding doors are provided. In addition, a part of the cover is frequently provided with a slide, or a removable or pivotable lid, consisting of transparent glass or metal. The two side sliding doors are for loading the balance scale with low containers set on it, from the right or the left side of the balance. The closable opening in the cover of the structure is for loading relatively tall containers and, for pipetting slender-necked laboratory containers.
These balances are primarily high resolution analytical balances having electronic displays. Accordingly, the material to be weighed is located in the weighing area, which is closed on all sides and screens the balance scale during the weighing, from disturbing external influences, which could distort the weighing result.
Bordering the glass with a metallic supporting framework makes it more difficult, to a greater or lesser extent, to see into the weighing area. This also applies to the accessibility of the weighing area and of the balance scale from the side, especially if the boxlike structure is relatively low.
Summary
This invention has the task of making it easier to see into the weighing area and of improving the accessibility of the weighing area of the balance scale in a balance, without adversely affecting the stability of the structure.
The invention solves this task by providing a load carrying transparent front pane having at least one holding and guide track secured to its top edge that extends longitudinally along the top of the structure to the back wall. Sliding side doors are provided in the structure and have bent extensions corresponding to the top of the structure. By opening the sliding side doors the scale can be accessed from the sides and top.
Brief Description of the Drawings
The concept of the invention is explained in several embodiments with reference made to the drawings.
FIG. 1 shows a perspective view of the balance.
FIG. 2 shows a detailed sectional view through the slide guide along line 2--2 in FIG. 1.
FIG. 3 shows a detailed sectional view through the sliding door guide in the base along line 3--3 in FIG. 1.
FIG. 4 shows a detailed view of the sliding door guide in the housing base at the rear foot.
FIGS. 5, 6 and 7 show a proportional side, front and top view of the balance of FIG. 1.
FIG. 8 shows a side view of a balance according to FIG. 1 and FIG. 5 with elevated construction.
FIG. 9 shows a top view of a varient of FIG. 7 with a centrally located holding and guide track.
FIG. 10 shows a top view of a variant of FIG. 7 and FIG. 9 with an off center holding and guide track.
FIG. 11 shows a perspective view of another varient.
Detail Description
In the preferred embodiment, illustrated in FIGS. 1 to 8, the balance comprises housing base 1 which houses all of the electric and electronic components and has an electronic display and operating console 3 in front. Console 3 comprises digital display 4", tare key 4' and other keys 4 having alphanumeric symbols. Box-like structure 2 is built around balance scale 28 and is rigidly connected to housing base 1. In the preferred embodiment this box-like structure is enclosed with transparent glass on both sides, the cover and also on the back wall. Front pane 6 and back wall 7 are rigidly connected to housing base 1 by clamping bearings 21. Front pane 6 and back wall 7 are connected at their upper edges to two holding and guide tracks 15, 16 which run parallel to the central longitudinal axis of the balance and are spaced from the side edges of the box-like structure. The guide tracks are provided with clamping bearings 22, and optionally screw bearings, at their ends for holding two all-glass panes 6, 7.
As is evident from FIG. 2, the two holding and guide tracks 15, 16 are constructed in such a manner that top slide 12 can be longitudinally shifted in the cover of the structure in guide groove 18 formed by the tracks. Bent sides 9, 11 are likewise guided in guide groove 19 of the tracks with the aid of guide profile 20. The lateral accessibility of weighing area 5 is considerably improved by bent sliding doors 9, 11 having horizontal extensions, so that relatively low containers set on balance scale 28 can be placed obliquely from above. Balance scale 28 is protected against lateral jolts by housing collar 27 in bottom 26 of weighing area 5.
Relatively high and slender containers, e.g. with liquids, can be placed and pipetted via slide 12 in the cover. Sliding doors 8, 19 and slide 12 have screw down grips 13, 14 formed from plastic or glass.
In order to support the longitudinal movement of sliding doors 8, 10 in the tracks, especially when the sliding doors are fully extended, an additional guide tube 23 in the form of a low-friction plastic channel is located in housing base 1. As can be seen from FIGS. 3 and 4, rod 24 runs along the entire length of the lower sliding door guide in plastic channel 23. The rear ends of sliding doors 8, 10 are supported on bearing clamp 25 on the rear end of rod 24 which prevents opened sliding doors 8, 10 from tipping.
If rear wall 7 is not formed of metal, but rather, as is shown and described, of an all-glass pane, it is recommended for reasons of strength to provide additional bracing of the structure. This is accomplished in the embodiments shown by metallic bracing bracket 17, which is located in the rear area of the structure, and is fastened to both sides of housing base 1 and connects the two sides in a U-shaped manner like a roll-over bar. Bracket 17 extends in a protective manner over the two sliding doors 8, 10, slide 12 and the two holding and guide tracks 15, 16 and fixes the latter to the rear of the scale in addition to the fastening to rear wall 7. As such, the total structure forms a bend-resistant and torsion-resistant box rigidly connected to housing base 1.
FIGS. 5 through 8 essentially show the embodiment of FIG. 1. FIGS. 5 and 6 show a relatively low structure 2 while FIG. 8 shows an extremely tall structure 2. It is especially advantageous to have a bracing means with two holding and guide tracks 15, 16 for the tall structure of FIG. 8.
In contrast thereto, FIG. 9 shows an embodiment for loading the weighing scale with relatively low, weighing material, such as tablets, jewels and other weighing material in small format. For such applications the weighing area can be kept relatively low. The bracing is achieved according to FIG. 9 by a single holding and guide track 15' positioned along the central longitudinal axis. Sliding doors 8', 10' bent to this holding and guide track 15' permit a favorable selective loading of balance scale 28 from both sides.
FIG. 10 shows an embodiment in which a single holding and guide track 15" is positioned asymmetically to the side of the central longitudinal axis and divides the cover of the structure approximately 1/3 to 2/3 along the central longitudinal axis. Containers having a narrow bottleneck, are not covered by the open structure in this embodiment by holding and guide track 15" which shows the wide extension 11" and are therefore also accessible from the top when sliding door 10' is open. Open sliding door 8', which shows the small extension 9' is used primarily for loading the balance scale or flat containers thereon from the side.
Sliding doors 8, 8', 10, 10' are preferably constructed in one piece, whereby the horizontal extension merges with the vertical plane of the door by a rounded contour into the plane of the cover.
The term "transparent glass" is also intended to include other transparent sheet materials, such as transparent plastic, which may exhibit advantageous qualities appropriate for the present usage.
A preferred embodiment according to FIG. 11 is constructed analogously to the embodiment of FIG. 10. In distinction thereto, sliding door 8' with the small horizontal extension is located on the other side and structure 2 is constructed as an independent, self-carrying cuboid box. Horizontal connected frame 29 or a connection plate connects all vertical structural members to the unit, and structure 2 is connected to base 1 by screws 30 or by other detachable connection elements.