Abstract:
A pan lifting device configured to grip a pan of a balance with a positive fit has a pincer-shaped end ( 12 ) and a handle ( 14 ). A blade-shaped supporting projection ( 16 ) of the pan lifting device is configured to accommodate the bottom ( 28 ) of the pan and a bent-over beak ( 18 ) of the pan lifting device is configured to clamp the rim ( 30 ) of the pan.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a Continuation of International Application PCT/EP2014/003369, which has an international filing date of Dec. 16, 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 114 161.7, filed Dec. 17, 2013, which is also incorporated in its entirety into the present Continuation by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a pan lifting device configured to grip a pan of a balance with a positive fit, wherein the pan has a bottom and an upwardly projecting peripheral rim. 
     The invention relates, in particular, to a pan lifting device configured to grip a disposable pan of a drying balance. In drying balances, the sample to be weighed is tested for its water content. Herein, the sample to be weighed is first weighed and subsequently subjected to a defined heat treatment. 
     BACKGROUND 
     A method for determining the water content using a drying balance is described in DE 38 32 726 C2. 
     EP 1 004 859 B1 discloses a drying balance wherein a cover is moved over the removable pan in order to close a weighing chamber. In order to remove the pan, the cover is moved back again into the housing of the drying balance. In this way, the accessibility of the pan is optimized. 
     However, there are also drying balances, i.e. above all, top-pan drying balances in which no movable cover is present, so that the weighing chamber is closed and is accessible via a hinged cover. Herein, the pan must be introduced into the weighing chamber laterally. As known, it is herein important that the pan is handled with a tool in order not to leave any contaminants on the pan. 
     A pan lifting device for gripping and conveying a pan is described in DE 202 10 500 U1. This pan lifting device is placed on the pan from above, wherein a handle extends vertically and has two limbs extending in opposing directions from its lower end. Mounted at the end of each of these limbs are U-shaped receptacles which, approaching from above, encompass the rim of the pan and extend as far as the bottom. Thus the pan is grasped from the diametrically opposite side in that the limbs press radially and against one another. 
     Forceps and pincers are known from U.S. Pat. No. 2,595,683 A, DE 20 2012 102 499 U1 and US 2005/0001439 A1 for entirely different purposes are not suitable for gripping a balance pan laterally, since on axial clamping, the pan would tilt in the forceps or pincers. 
     From U.S. Pat. No. 1,541,738 A, there is known a pincer-like kitchen lifting tool wherein two handle limbs are connected to one another via a hinge. A leaf spring presses the handle ends apart and thereby presses the gripping portions disposed before the hinge toward one another. A lower portion has a plate-shaped supporting projection. Using the universal pincers disclosed, it is intended that different pans can be lifted. 
     FR 784 609 A describes a clamping device for pans wherein, however, the upper handle and the lower handle transition into one another on the rear-side handle end. The lower grip limb has a plate-like projection which comes to lie under the pan, whereas the upper-side handle limb has a hook-shaped projection which, on pressing together the handle limbs, comes to lie against the inside of the pan. 
     Another pan lifter in the form of pincers is known from FR 788 517 A. This pan lifter is configured like a pair of shears or pincers, and formed onto the lower handle end is a plate-like projection which lies under the pan, and at the upper handle end an upwardly open U-shaped projection which is intended to grip the upper edge of the pan. 
     U.S. Pat. No. 2,333,564 A describes a pan lifter, the lower handle limb of which is configured as a planar part. With a pivot axis, an upper handle limb is pivotably articulated on the lower handle limb. In the region of the ends of the handle limbs, a compression spring which pre-tensions the pan lifter into a clamping position is arranged between the handle limbs. FR 2 406 985 A1 discloses a very similar pair of pincers. 
     SUMMARY 
     It is an object of the invention to provide a pan lifting device for a drying balance which enables easier handling of the pan, particularly in drying balances which have a hinged cover for opening the weighing chamber. 
     In drying balances of this type, a disadvantage of the known pan lifting device is that it requires much space during its use. 
     This and other objects are achieved with a pan lifting device wherein the pan lifting device has a pan-side pincer-shaped end and an oppositely-arranged handle, wherein the pincer-shaped end has a blade-shaped supporting projection which is configured to lie under the bottom of the pan, and has a beak which is configured to move toward and away from the supporting projection and is positioned over the supporting projection, is bent over and positively grips and clamps the rim of the pan. The supporting projection forms, in the direction opposed to the handle, the furthest forwardly projecting part of the pan lifting device. In the pan lifting device according to the invention, the two portions which engage with the pan are arranged one over the other and movable relative to one another. The supporting projection supports the bottom so that the bottom of the pan lies thereon. The beak, however, engages the rim portion of the pan lying thereabove and grips it so that the pan is clamped only in a narrow region and is thus removable laterally from the weighing chamber. Thus the operator does not have to reach into the weighing chamber with a hand, but can remove the pan from outside. The handle has two handle limbs which are movable relative to one another, specifically an upper limb and a lower limb. One handle limb is coupled to the supporting projection and the other handle limb is coupled to the beak, so that with a relative movement of the handle limbs, the supporting projection and the beak are moved relative to one another in order to open or close the pincer-shaped end. 
     The operation of the pan lifting device therefore takes place on the handle itself. The two handle limbs transition into one another to form a hinge or are coupled to one another there. In this manner, parts are spared and the pan lifting device can configured very easily and very simply. The upper handle limb is coupled to the supporting projection and the lower limb is coupled to the beak situated thereabove, so that seen in a side view, the handle limbs cross one another. The crossing site which is formed thereby is configured such that one handle limb has a through opening through which the other handle limb extends. The crossing site should be configured large enough so that a relative movement of the handle limbs is possible for opening and closing the pincer-shaped end. 
     Preferably, the handle is angled slightly upwardly relative to the supporting projection, but with the pan in use, extends substantially horizontally. This allows, as with a kitchen lifting device, the pan lifting device to be grasped and pushed under the pan. 
     In that the beak is movable relative to the supporting projection, with the pan lifting device opened, it is offset upwardly so that firstly the supporting projection is pushed under the pan. Subsequently, the beak engages on the rim, approaching from above, in order to clamp the pan. 
     One embodiment of the invention provides that the handle limbs transition into one another at the free handle end, in particular, forming a U-shape. Thus, the middle section of the “U” effectively forms the hinge. 
     The handle limbs can transition integrally into the supporting projection and into the beak, i.e. one handle limb transitions integrally into the supporting projection and the other into the beak. In this context, it can be advantageous if the handle limbs consist at least partially of plastics, so that the supporting projection and the beak are made of plastics. This allows gentle handling of the pan. 
     The handle limbs can be configured resilient relative to one another, i.e. a resiliently pre-tensioned starting position can be pre-determined and the handle limbs must then be moved against the spring force in order to open or close the pincer-shaped end. 
     A leaf spring which is connected to the handle limbs and which imparts the resilient effect can be integrated into the handle. Alternatively, the handle limbs can be configured as leaf springs in that a U-shaped or V-shaped leaf spring forms the two handle limbs with its limbs. In this embodiment, the supporting projection and the beak are then mounted on the respective leaf spring limbs, for example, by gluing, injection molding, screw fixing or other fastening types. 
     The preferred embodiment provides that the pan lifting device has no hinge with a separate axis, but that the mobility of the pan lifting device for opening and closing the pincer-shaped end is possible exclusively by elastic deformation of the pan lifting device. 
     The supporting projection tapers, for example, toward the free end, seen in plan view, and/or becomes continually thinner in its height, that is, in its vertical height toward the free end. These variants permit the supporting projection to be easily pushed under the pan base. 
     The supporting projection transitions on the handle-side end into an upwardly projecting shoulder. The beak has at least one downwardly projecting bent-over portion which is movable relative to the side surface of the shoulder which is associated with the pan rim and against which the pan rim lies. Thus, with the pincer-shaped end open, the beak extends upwardly so far that the supporting projection can be pushed under the bottom until the contacting of the pan rim against the shoulder without the beak causing an obstruction. Subsequently, the beak is moved downwardly. In this manner, the rim of the pan is laterally clamped between the bent-over portion or portions and the shoulder. The bent-over portion then lies against the inside of the pan rim and the outside of the pan rim is pressed against the shoulder, or more accurately stated, against the side surface of the shoulder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the invention are disclosed in the following description and the attached drawings, to which reference will be made. In the drawings: 
         FIG. 1  is a perspective view of a first embodiment of the pan lifting device according to the invention, 
         FIG. 2  is a longitudinal sectional view through the pan lifting device of  FIG. 1  in the opened state, 
         FIG. 3  is a longitudinal sectional view through the pan lifting device of  FIG. 1  in the closed state, 
         FIG. 4  is a perspective view of a second embodiment of the pan lifting device according to the invention, and 
         FIG. 5  is a perspective view of a third embodiment of the pan lifting device according to the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a pan lifting device  10  which serves for laterally inserting and removing a disposable pan in the weighing chamber of a drying balance. 
     The pan lifting device  10  comprises a plurality of sections, specifically a pan-side, pincer-shaped end  12  and a handle  14  opposite thereto. 
     The overall form of the pan lifting device is elongate, wherein in a side view (see  FIG. 1 ), the handle  14  is bent-over upwardly somewhat in relation to the pincer-shaped end  12 . In this way, the user can still reach with the fingers under the handle when the pincer-shaped end is already placed on a bottom of the drying balance or on a placement surface. 
     The pincer-shaped end  12  comprises two portions or parts movable toward and away from one another, specifically a blade-shaped supporting projection  16  and a slightly laterally offset beak  18 , lying thereabove and extending less far forward. 
     The supporting projection  16  thus represents, in the opposite direction to the handle  14 , the furthest forward projecting part of the pan lifting device. 
     As is clearly apparent in  FIGS. 1 to 3 , the supporting projection  16  tapers toward its free end  19 , preferably conically. 
     Alternatively or additionally, the height or thickness of the supporting projection becomes ever less toward the free end  19 , as is also clearly apparent from  FIGS. 1 to 3 . 
     The shell-shaped pan lies with its bottom  28  on the upper side  20  of the supporting projection. 
     The supporting projection  16  transitions into an upwardly projecting shoulder  22  or is delimited thereby, wherein the shoulder  22  has a side surface  24  facing toward the supporting projection  16 , on which the outer rim  30  of the pan lies (see  FIG. 3 ) on gripping the pan. 
     The beak  18  has at its front end, i.e. the end close to the supporting projection, a plurality of downwardly bent-over portions  26 . Since the shoulder  22  has a circular segment form which corresponds to the circular form of the pan rim  30 , the bent-over portions  26  also lie on the circular path, seen in plan view. 
     With the pincer-shaped end closed (see  FIG. 3 ), the bent-over portions  26  lie against the side surface  24  or are spaced therefrom with a minimum gap so that the pan rim  30  is clamped between the side surface  24  and the opposite inner side of the bent-over portions  26 . 
     The bent-over portions  26  are peripherally separated from one another and spaced so that point-type clamping sites are produced. This ensures the stable holding of the very thin pan. 
     In  FIG. 3 , a clamped pan is drawn in with dashed lines. 
     The supporting projection  16  and the beak  18  transition into the handle  14 . 
     The handle  14  has two handle limbs extending toward one another, specifically an upper handle limb  32  and a lower hand limb  34 . 
     The handle limbs  32 ,  34  are connected to one another at the free handle end. The line in  FIG. 1  symbolizes the interface  36  of the two handle limbs  32 ,  34  manufactured as separate parts. In this region, the handle limbs  32 ,  34  are, for example, screwed to one another. The screw fixing itself is arranged on the rear side so that it is not visible in  FIG. 1 . 
     The handle limbs  32 ,  34  therefore form a U-shape wherein the central portion of the “U” forms a type of hinge  52  which is formed without an axis or an additional part. 
     The upper handle limb  32  transitions, as is to be understood herein as exemplary and not limiting, integrally into the supporting projection  16 . The lower handle limb transitions, as is also to be understood herein as exemplary and not limiting, integrally into the beak  18 . Since, therefore, the upper handle limb  32  is coupled to the supporting projection  16  arranged under the beak  18 , the handle limbs  32 ,  34  cross one another, as shown in  FIGS. 1 to 3 . The result is a crossing site  40 . 
     The crossing site  40  is configured in the embodiment shown in that the upper handle limb  32  has a, preferably elongate, through opening  42  through which the lower handle limb  34  extends. 
     The through opening  42  is configured as an elongate window and is thus peripherally closed in the embodiment shown. 
     Alternatively, the opening  42  can naturally also be configured as a laterally open cut-out, i.e. not configured as a closed window. 
     Furthermore, the through opening  42  can naturally also be conversely provided on the lower handle limb  34 . 
     Integrated into the handle  14  is a spring, in this case a leaf spring  50 , which presses the handle limbs  32 ,  34  away from one another. However, since the handle limbs  32 ,  34  joined to the supporting projection  16  and to the beak  18  cross one another, the leaf spring  50  has the effect that in the non-actuated starting position (rest position), the pincer-shaped end  12  is closed ( FIG. 3 ). 
     In order to open the pincer-shaped end  12 , the handle must be pressed together such that, with regard to  FIGS. 2 and 3 , the handle limbs  32 ,  34  are moved toward one another. Then the opened position is produced ( FIG. 2 ). 
     The leaf spring  50  is configured U-shaped in the embodiment shown. At the U-shaped connecting portion (hinge  52 ) of the two handle limbs  32 ,  34 , the leaf spring  50  extends externally. However, thereafter (see  FIGS. 2 and 3 ), the two limbs  54 ,  56  extend along the inside, i.e. on sides of the handle limbs  32  or  34  facing one another and lie thereagainst. 
     The leaf spring  50  is laterally guided and held by projections  58  on the inside of the handle limbs  32 ,  34 , so that no further, dedicated fasteners are needed. 
     The handle limbs  32 ,  34  and the supporting projection  16  and the beak  18  are made of plastics, particularly forming two plastics parts. 
     For assembly, the rear end of the lower handle limb  34  is pushed from the front through the through opening  42 . Then, the handle limbs  32 ,  34  are connected to one another in the region of the interface  36 . This connection can also be configured positively fitting without screw connections or other fasteners being needed. For example, a type of tongue and groove connection or a locking connection could be implemented. 
     If required, it is also possible for the pan lifting device  10  to be made without a leaf spring, so that the spring effect is realized purely through the two handle limbs  32 ,  34  without an additional part. 
     The embodiment according to  FIG. 4  corresponds to that of  FIGS. 1 to 3  except for a few details, so that reference can be made to the entire content of the preceding embodiment, and the embodiment as per  FIG. 4  can be regarded, with respect to any individual features, as analogous to that of  FIGS. 1 to 3 , except for the following differences. 
     In the embodiment of  FIG. 4 , the leaf spring  50  is configured somewhat differently. 
     Specifically, the leaf spring has a greater width in the region of the central section than in the region of the two limbs of the U. In the U-shaped region, the leaf spring  50  has the reference sign  70 . The narrower portion (limb  56 ) which again lies on the inside is situated in the region of the limbs  32 ,  34 . Here also, the leaf spring  50  extends on the outside in the region of the hinge  52  and otherwise on the inner sides of the handle limbs  32 ,  34  which face one another. 
     It is also possible, in general, thus not restricted to this embodiment, to injection mold at least one handle limb  32 ,  34  directly onto the leaf spring and to insert the other limb of the leaf spring  50  into the other handle limb  34  or  32  or, more generally, to fasten it thereto. 
     Whereas in the previous embodiments, the handle limbs  32 ,  34  transition integrally into the associated portions of the pincer-shaped end  12  (supporting projection and beak), specifically integrally, in the embodiment of  FIG. 5  it is provided that the handle  14  and the pincer-side end  12  consist of different parts. 
     The handle  14  is formed by the leaf spring  50  so that the leaf spring  50  also defines the handle limbs  32 ,  34  and the central portion of the U-shaped leaf spring  50  forms a hinge  52 . 
     For better handling, although this should not be understood as restrictive, a plastics part  80  which facilitates handling can be mounted on the upper and/or lower handle limb  32 ,  34 . 
     On the upper handle limb which crosses the lower handle limb  34 , there is a part  82  mounted, for example by injection molding or screw fastening, clamping or the like, whereas the beak  18  is mounted on the lower handle limb, also by a screw fastening, clamping connection, locking connection or the like, or by injection molding on. 
     The part  82  then comprises the supporting projection  16  and the shoulder with the side surface  24 . 
     In this embodiment, purely by way of example, two bent-over portions  26  are provided. Otherwise, the details of this embodiment also correspond to the embodiments above. 
     The underside  90  of the bent-over end of the handle lies in a plane E in which a, for example, planar portion of the underside  92  of the end  12  also lies, so that a stable placement surface results. In this manner, a pan lifting device  10  lies safely on a surface, even with a clamped pan. 
     LIST OF REFERENCE SIGNS 
     
         
           10  Pan lifting device 
           12  End 
           14  Handle 
           16  Supporting projection 
           18  Beak 
           19  End 
           20  Upper side 
           22  Shoulder 
           24  Side surface 
           26  Bent-over portion 
           28  Bottom 
           30  Pan rim 
           32  Handle limb 
           34  Handle limb 
           36  Interface 
           40  Crossing site 
           42  Through opening 
           50  Leaf spring 
           52  Hinge 
           54  Limb 
           56  Limb 
           58  Projections 
           70  U-shaped region 
           80  Plastics part 
           82  Part 
           90  Underside 
           92  Underside