FR2588384A1 - ELECTRICAL MEASUREMENT INSTRUMENT COVER HOUSING WITH EXCHANGEABLE GRADUATION - Google Patents

Abstract

THE INVENTION RELATES TO A BOX WITH A COVER FOR AN ELECTRIC MEASURING INSTRUMENT WITH EXCHANGEABLE GRADUATION. THE UPPER WALL 2 OF THE BOX INCLUDES A MOBILE COVER 5 WHICH, WHEN OPEN, ALLOWS ACCESS TO THE GRADUATED SCALE OF THE INSTRUMENT. IN THE CLOSED POSITION, GRADUATION IS HELD FIXED AND DUST CANNOT ENTER THE INSIDE OF THE INSTRUMENT. FIELD OF APPLICATION: BOXES FOR ELECTRICAL MEASURING INSTRUMENTS.

Description

The subject of the invention is a housing for covering

  key of an electrical measuring instrument to exchange the graduation of a calibrated and closed instrument. There are many forms of realization

  known instrument cases with exchangeable graduation.

  German Patent Application No. 16 94 884 discloses an embodiment in which part of the graduation can be exchanged by being attached to the basic graduated surface by means of special buttons.

  with elastic engagement. The disadvantage of this solution

  tion is that it requires the removal of protective glass

of the instrument.

  Another known solution, described in the German patent application N 22 63 836, uses a guide groove of the graduation, formed by the casing and the shell, and the housing has, on a

  side, an opening allowing extraction and introduc-

  graduation. The opening is covered with a lid that also holds the protective glass

and the bootmaker's mask.

  Another known solution, described in the German patent application N 29 05 318, uses a casing whose walls and bottom form a single block, and the graduation can be changed by means of an opening in the wall and closed by

  a lid that can rotate with two hinges.

  The lid is captive and closes automatically when the graduation is inserted into the cutout of the instrument panel, but only in the case where each instrument cabinet is inserted into the instrument panel.

own cutout.

  Other known solutions, in accordance with German Patent Nos. N 27 47 879, N 27 44 582 and N 27 19 389, European Patent No. 44 542 and British Patents Nos. 2 013 889 and 2 046 913, are designed in such a way that opening for the exchange of the graduation is located in the housing. In these solutions, there is the possibility of a loss of the lid during the exchange of the graduation and the introduction of

  the instrument having an open opening. The characteristics

  The common characteristics of all the solutions described are relatively

  complex of the instrument cabinet.

  The object of the invention is to provide an electrical measuring instrument casing cover which makes it possible to simply exchange the scale of a closed and calibrated instrument, in such a way that the overall construction is not bulky. and simple. The cover intended to cover the graduation exchange opening shall be made in such a way that

  to be captive. It must close automatically.

  When attempting to insert the instrument with a partially open cover into the instrument panel, the cover closes independently of the mounting. Measurement defects due to tolerances must

be negligible.

  The invention has solved the existing problem by using a lid mounted on a rectangular instrument casing whose graduation exchange opening is located between the mask and an upper wall. The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting example and in which: - Figure 1 is a partial view of

  perspective of the lid of an electronic measuring instrument

  exchangeable scale according to the invention, the lid being shown open at I and closed in

II;

  - Figure 2 is a section along the line A-A of Figure 1; - Figure 3 is a plan view of the housing whose cover is removed; and FIG. 4 is an axonometric view

  from the underside of the lid.

  As shown clearly in FIG. 1, the casing of the instrument comprises, on its upper face, a cover 5 which can be moved on

  along a wall portion 3 extending the upper wall

  2 of the box. Part I shown on the left in Figure 1 shows the cover 5 in its open state, to remove the graduation 12 of the housing

  of the measuring instrument, whereas Part II,

  shown on the right in Figure 1, shows the lid in its closed state. The wall portion 3 of the one-piece instrument housing follows the top wall 2 in the direction of the graduation 12 and is thinned, as clearly shown in FIG. 2. In the middle, the portion

  3 has an extension 4 on the underside

  a lug 13 is formed and, in addition, the portion 3 is reduced relative to the vertical walls 1 of the casing so that a notch 8 is formed on both sides of the walls 1. A connecting flange 10 is located at ends of the side walls 1 of the

  housing and a mask 11 is inserted into this flange.

  The upper edge of the mask 11 covers -the space between the flanged ends 10 so that a frame (not shown) can be fixed from above, this frame fixing, in addition to the mask, also the protective glass (not shown). ) of the instrument on the cabinet of the latter.

  The cover 5 shown in FIG.

  an opening or groove 6 located between the upper wall 17 and the lower wall 18, the walls

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  17 and 18 being connected by a band. In the middle of the lower wall 18, a cutout 14 is formed of

  way to communicate with the groove 6. On its trans-

  versaux, the upper wall 17 is extended by rectangular edges 7 while the outer surface of the wall 17 has notches 16 which facilitate the displacement of the lid 5. Lugs 9 are formed at both ends of the upper wall 17 to make protruding in the longitudinal direction of the cover 5. The cover 5 is placed on the wall portion 3 so that the latter can be slid into the groove 6. Simultaneously, the edges 7 slide in the notches 8 which guide them. In

  the closed position of the lid 5, the pin 13 of the extension

  4 snaps resiliently into the cutout 14 of the cover, thereby securing it in its position. When the cover 5 is closed (part II of FIG. 1), the tabs 9 penetrate into corresponding recesses 19 of the flange 10 and the mask 11 so that the inner surface of the flange 10 and that of the mask 11, which stops on the panel of the instrument, are entirely in the same plane. Using the tabs 9 which abut against the panel of the instrument when the instrument casing is inserted into the panel, it prevents

  the cover 5 can remain in its open position.

  When the lid 5 is closed, its front end slips into a groove 15 formed in the mask 11, thus preventing the lid 5 from folding.

  as well as dust getting inside the instrument

  is lying. It goes without saying that many modifications can be made to the described instrument case

  and shown without departing from the scope of the invention.

Claims (1)

CLAIM   Cover housing for an exchangeable electrical measuring instrument, characterized in that, in the direction towards the instrument scale (12), the upper wall (2) of the rectangular housing is extended by means of a step, by a portion (3) of wall whose end edge is spaced from the plane of the graduation (12) and comprises, in its middle, a rectangular extension (4) on the lower face of which a lug (13) is formed ; in that the wall portion (3) is reduced at its lateral ends, forming stepped notches (8) in side walls (1), in that the wall portion (3) can be movably inserted into a groove (6) formed between an upper wall (17) and a lower wall (18) of a lid (5), the lower wall (18) having in its middle a cut-out (14) for the elastic engagement, in this cutting, the lug (13) when the lid (5) is open; in that the edges (7) of the lid (5) are folded downwards and penetrate into the notches (8) of the walls (1), in that the end part of the side walls (1) has a flange (10). linkage in which a mask (11) is introduced, in that the outer ends of the cover (5) directed towards the flange (10) comprise tabs (9) which, when the lid (5) is closed, penetrate into recesses (19) formed in the flange (10) and in the mask (11), and in that the outer edge of the lid (5), in its closed position, is pushed into a groove (15) located in the mask (11).