Electronic balance windshield

Abstract

To provide a windshield for an electronic balance having a simple structure, easy to assemble, and slidable side plates. [Solution] The front and rear plates 51 are fixed to a base 11 placed on the main case of the electronic balance, guide grooves 56a, 56b are formed on both side ends of the rear plate 51, and the pair of left and right side plates 31, 41 are provided with engagement plates 33, 44 that engage with the corresponding guide grooves 56a, 56b, respectively. These engagement plates 33, 44 are guided by the guide grooves 56a, 56b, thereby slidably supporting the pair of left and right side plates 31, 41 on the side ends of the rear plate 51, and the cover plate 61 has cutouts that allow the pair of left and right side plates 31, 41 to slide, and is engaged with the upper ends of the front plate, rear plate 51, and pair of left and right side plates 31, 41.

Description

[Technical Field]

[0001] The present invention relates to a windshield that forms a weighing chamber of an electronic balance that weighs a sample placed on a weighing pan inside the weighing chamber, and more particularly to an assembly-type windshield. [Background technology]

[0002] In electronic balances, air flow around the weighing pan, such as that caused by air conditioning, breathing while weighing, or airflow caused by walking, can act as wind pressure on the weighing pan, adversely affecting the weighing and making accurate measurements impossible. To prevent this adverse effect, a windshield has traditionally been provided to shield the weighing chamber, the weighing space containing the weighing pan, from the outside. These windshields can be broadly divided into two types: those with a pair of openable side panels that are pre-attached to the main body case of the electronic balance, and those with an assembly system in which multiple components, such as a front panel, a rear panel, a pair of side panels, and a cover, are assembled and placed on the main body case. The assembly system requires four pillars to support the front panel, rear panel, and a pair of side panels, making assembly complicated. Furthermore, when weighing, in order to place the sample on the weighing pan inside the weighing chamber, it is necessary to remove the cover plate or one of the side plates to secure an opening, and in some cases the weighing is performed with the cover plate or side plate removed, which creates the problem that the shielding function is inferior to that of the integrated type, in which the opening is secured by opening and closing the side plate (Patent Document 1).

[0003] To solve the above-mentioned problems, it has been proposed in the past to provide an assembled windshield for an electronic balance that does not require four pillars, but instead uses connecting rods installed on the outside of the rear plate to pull the upper and lower plates together, thereby sandwiching the front and rear plates together to form the framework of the weighing chamber, and the side plates slide back and forth along grooves formed in the lower plate to act as sliding doors for the weighing chamber, allowing samples to be inserted and removed by sliding the sliding doors, i.e., the side plates, open (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-130721 [Patent Document 2] Japanese Patent Application Publication No. 10-239139 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional windshields for electronic balances with sliding side panels, as described above, are configured to clamp the front and rear panels together by connecting rods installed on the outside of the rear panel to attract the upper and lower panels. However, excessive force applied by the connecting rods to the upper and lower panels prevents the side panels from sliding smoothly, while insufficient force results in the side panels being prone to accidental disassembly after assembly. Furthermore, since space must be secured outside the rear panel to accommodate the connecting rods, extra space outside the weighing chamber is required, making it difficult to miniaturize the electronic balance. Furthermore, the need for an extra component, the connecting rods, complicates assembly work. Furthermore, the side panels slide while being guided by grooves in the lower panel, but debris tends to accumulate in these grooves, making it difficult to remove the debris.

[0006] The present invention has been made to solve many of the problems mentioned above, and its object is to provide a windshield for an electronic balance that has a simple structure, is easy to assemble, and has sliding side panels. [Means for solving the problem]

[0007] In order to achieve the above object, a first aspect of the windshield for an electronic balance according to the present invention is a windshield consisting of a base that is placed on the main case of the electronic balance to form a weighing chamber on the main case, a front plate, a rear plate, a pair of side plates, and a cover plate, wherein the front plate and the rear plate are fixed to the base, guide grooves are formed on both side edges of the rear plate, and each of the pair of side plates is provided with an engaging protrusion that engages with the corresponding guide groove, and these engaging protrusions are guided by the guide grooves to slidably support the pair of side plates on the side edges of the rear plate, and the cover plate has cutouts that allow the pair of side plates to slide, and is engaged with the upper ends of the front plate, the rear plate, and the pair of side plates.

[0008] In a second aspect, in the first aspect described above, each guide groove is formed diagonally downward from each side end on the upper part of the rear plate, and each engaging protrusion consists of a plate-shaped protrusion extending widthwise on the upper part of each side plate.

[0009] In yet another aspect, in each of the first and second aspects described above, each side panel is provided with a front blocking portion that abuts against the inside of the front panel to block the inflow of air from the outside when slid all the way toward the front panel, and a rear blocking portion that abuts against the outside of the rear panel to block the inflow of air from the outside.

[0010] In yet another aspect, in each of the first and second aspects described above, the cover plate is provided with a restraining portion around its periphery that prevents the upper portions of the front plate, the rear plate, and the pair of side plates from opening outward. [Effects of the Invention]

[0011] According to the present invention, the structure is simple, assembly is easy, the weighing chamber has a slidable side panel and has excellent shielding properties, and furthermore, it is easy to clean out dust inside the weighing chamber. [Brief explanation of the drawings]

[0012] [Figure 1]FIG. 1 is a side view showing an electronic balance with an assembled windshield placed on a main body case according to an embodiment. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. 10 is a cross-sectional view showing the engagement state between the guide groove and the engagement protrusion plate. DETAILED DESCRIPTION OF THE INVENTION

[0013] A preferred embodiment of the present invention will now be described with reference to the accompanying drawings. 1, electronic balance 1 includes a main body case 2 that houses a weighing mechanism (not shown) including a mass sensor such as an electromagnetic balance or load cell connected to a weighing pan (not shown) on which a sample to be weighed is placed, and a control unit (not shown) that controls various operations of the electronic balance. Also, an assembled windshield 10 is placed on top of the main body case 2, forming a weighing chamber, which is a measuring space in which the weighing pan is located.

[0014] As shown in Figures 1 and 2, the windshield 10 comprises a base 11, a front plate 21, a pair of left and right side plates 31 and 41, a rear plate 51, and a cover plate 61. The windshield 10 forms a measuring chamber, which is a shielded rectangular parallelepiped measuring space. The base 11, the front plate 21, the pair of left and right side plates 31 and 41, the rear plate 51, and the cover plate 61 that constitute the windshield 10 are made of synthetic resin. In order to visually check the inside of the measuring chamber, it is preferable that each of the plates 21, 31, 41, 51, and 61, excluding the base 11, be see-through; however, it is not necessary that all of the plates 21, 31, 41, 51, and 61 be see-through, and all of them may not be see-through. The windshield 10 shields the inside of the measuring chamber during measurement, and prevents air flows during measurement, such as wind from an air conditioner, a person's breathing during measurement, or air flows generated when a person walks, from acting as wind pressure on the load-bearing part centered on the measuring pan and affecting the measurement.

[0015] Next, the components of the windshield 10, namely the base 11, the front plate 21, the pair of left and right side plates 31, 41, the rear plate 51, and the cover plate 61, will be described. As shown in FIG. 3, base 11 is a substantially rectangular frame in plan view, and its front-to-rear ends are provided with fixing plates 12 (only the front side is shown) with screw holes 13a, 13b for receiving fixing screws 71a, 71b (see FIGS. 1 and 2). Also, left and right ends of base 11 are provided with lower guide surfaces 14, 15 having an L-shaped cross section, each with horizontal surfaces 14a, 15a and vertical surfaces 14b, 15b. On the front-to-rear ends of each horizontal surface 14a, 15a, opposite the vertical surfaces 14b, 15b, protrusions 16a, 16b, 17a, 17b are provided. Upper frame 18 extends horizontally integrally from the upper ends of each vertical surface 14b, 15b, and has locking portions 19a, 19b, 19c, 19d at its four corners.

[0016] As shown in Figure 4, front plate 21 is fixed to fixed plate 12 on the front side of base 11, and its widthwise length is set to be the same as the widthwise length of upper frame 18 of base 11. Cutout steps 22a, 22b are formed on both sides of the lower end of front plate 21, with cutout step 22a engaging with locking portion 19a of base 11 and cutout step 22b engaging with locking portion 19b of base 11, and through holes 23a, 23b are formed at positions corresponding to screw holes 13a, 13b of base 11 in this locked state. Furthermore, oblong engagement holes 24a, 24b are formed at the upper end of front plate 21, and guide recesses 25a, 25b are formed above each of these engagement holes 24a, 24b on the outer surface of front plate 21, extending from the upper edge toward each of engagement holes 24a, 24b.

[0017] 5, rear plate 51 is fixed to a rear fixing plate (not shown) having the same configuration as front fixing plate 12 of base 11, and its widthwise length is set to be the same as the widthwise length of upper frame 18 of base 11. In other words, the widthwise length of rear plate 51 is the same as the widthwise length of front plate 21. Cutout step portions 52a, 52b are formed on both sides of the lower end of rear plate 51, and cutout step portion 52a is engaged with engaging portion 19c of base 11, and cutout step portion 52b is engaged with engaging portion 19d of base 11. Through holes 53a, 53b are formed at positions corresponding to screw holes into which fixing screws 71c (see FIG. 1) of a fixing plate (not shown) of base 11 are threaded in this engaged state. In addition, horizontally elongated engagement holes 54a, 54b are provided at the upper end of the rear plate 51, and further above each of these engagement holes 54a, 54b, guide recesses 55a, 55b are provided on the outer surface side, extending from the upper edge toward each of the engagement holes 54a, 54b.

[0018] 5 and 9, guide grooves 56a, 56b are formed obliquely downward from the upper end on both side edges of the rear plate 51. Protruding portions of the rear plate 51 corresponding to the side edges of the lower portions of these guide grooves 56a, 56b form support portions 57a, 57b that are formed thick in the thickness direction via a plurality of stair-like steps 58a, 58b, 58c, 58d on both the inner and outer sides.

[0019] Next, the pair of left and right side plates 31, 41 will be described. However, since these side plates 31, 41 are configured symmetrically, only the right side plate 31 will be described, and the description of the left side plate 41 will be omitted. As shown in FIG. 6, a handle 32 is provided on the outer surface of the right side plate 31. Furthermore, as shown in FIG. 7, an engagement plate 33 serving as an engagement protrusion that engages with one of the guide grooves 56a of the rear plate 51 is integrally provided on the upper end of the inner surface of the right side plate 31. This engagement plate 33 extends diagonally downward from the upper end of the right side plate 31 at an angle corresponding to the guide groove 56a and covers almost the entire width of the right side plate 31. Furthermore, a front blocking plate 34 serving as a front blocking portion that abuts against the inner surface of the front plate 31 to block the inflow of air from the outside is integrally provided on the inner surface of the right side plate 31, positioned slightly toward the rear end from the front side. Furthermore, a rear blocking plate 35 serving as a rear blocking portion that abuts against the outer surface of the rear plate 51 to block the inflow of air from the outside is integrally provided on the rear end.

[0020] In FIG. 9, reference numeral 44 denotes an engagement plate of the left side plate 41, which engages with the guide groove 56b of the rear plate 51.

[0021] As shown in FIGS. 1 and 2, the cover plate 61 is engaged with the upper ends of the front plate 21, the rear plate 51, and the pair of left and right side plates 31, 41. As shown in FIG. 8, the cover plate 61 has peripheral walls 62a, 62b, 62c, and 62d hanging down from its periphery, and the front and rear peripheral walls 62a and 62c have cutouts 63a, 63b, 63c, and 63d formed therein so that the upper ends of the pair of side plates 31, 41 can slide through. The peripheral walls 62a, 62b, 62c, and 62d constitute restraining portions that prevent the upper portions of the front plate 21, the rear plate 51, and the pair of side plates 31, 41 from opening outward. A through-hole 66 is formed in the center of the cover plate 61 so that a finger can be inserted to engage and release the cover plate 61 from the upper ends of the front plate 21, the rear plate 51, and the pair of side plates 31, 41.

[0022] As shown in Fig. 8, a locking protrusion 64a extending parallel to the peripheral wall 62a is provided on the inner surface of the cover plate 61 near the peripheral wall 62a, and the peripheral wall 62a and the locking protrusion 64a sandwich the upper end of the front plate 21 between them. As can be seen in Fig. 9, a locking protrusion 64b extending parallel to the peripheral wall 62c is provided on the inner surface of the cover plate 61 near the peripheral wall 62c, and the peripheral wall 62c and the locking protrusion 64b sandwich the upper end of the rear plate 51 between them. Furthermore, the inner surface of the peripheral wall 62a is provided with locking protrusions 65a and 65b that engage with the locking holes 24a and 24b of the front plate 21 during assembly, and the inner surface of the peripheral wall 62c is provided with locking protrusions 65c and 65d that engage with the locking holes 54a and 54b of the rear plate 51 during assembly (see Fig. 9). The engaging projections 65a, 65b, 65c, and 65d are formed with slopes so that they are guided by the guide recesses 25a, 25b, 55a, and 55b and project into the engaging holes 24a, 24b, 54a, and 54b.

[0023] Next, a method for assembling the windshield 10 will be described. First, when the inner surface of the lower end of the front plate 21 is brought into contact with the fixing plate 12 of the base 11 so that the notched step portions 22a, 22b of the front plate 21 are engaged with the locking portions 19a, 19b of the base 11, the through holes 23a, 23b of the front plate 21 correspond to the screw holes 13a, 13b of the base 11. Then, by inserting fixing screws 71a, 71b through the through holes 23a, 23b and screwing them into the screw holes 13a, 13b, the front plate 21 can be fixed to the base 11. Next, in a similar manner, the rear plate 51 is fixed to the base 11 with fixing screws 71c (only one is shown, see FIG. 1).

[0024] Next, the engagement plate 33 of the right side plate 31 is inserted obliquely from above into the guide groove 56a of the rear plate 51 to engage with it, supporting the right side plate 31 on the rear plate 51. At this time, the lower end surface of the right side plate 31 abuts against the horizontal surface 14a of the lower guide surface 14, and the inner side of the lower end abuts against the vertical surface 14b of the guide surface 14. In this state, the engagement plate 33 is supported and guided by the guide groove 56a, particularly the support portion 57a, and the right side plate 31 becomes slidable in the front-rear direction. The lower end of the right side plate 31 is additionally guided by the lower guide surface 14, making the sliding movement smoother. When the right side plate 31 is slid until its front closing plate 34 abuts against the inner side of the front plate 21, the closing plate 35 then abuts against the outer surface of the rear plate 51. This state is the closed state of the right side plate 31. Next, in the same manner, the left side plate 41 is supported on the rear plate 51 and made slidable in the front-rear direction, and the left side plate 41 is brought into a closed state.

[0025] Next, insert your fingers into the through holes 66 to pick up the cover plate 61, positioning the engagement protrusions 65a, 65b on the peripheral wall 62a in correspondence with the guide recesses 25a, 25b on the front plate 21 and the engagement protrusions 65c, 65d on the peripheral wall 62c in correspondence with the guide recesses 55a, 55b on the rear plate 51, and then pushing the cover plate 61 downward. Then, the engagement protrusions 65a, 65b are guided downward by the guide recesses 25a, 25b and engage with the engagement holes 24a, 24b. The engagement protrusions 65c, 65d are guided downward by the guide recesses 55a, 55b and engage with the engagement holes 54a, 54b. The inner surface of the peripheral wall 62b abuts against the outer upper edge of the right side plate 31, and the inner surface of the peripheral wall 62d abuts against the outer upper edge of the left side plate 41.

[0026] As a result, the cover plate 61 is engaged with the upper ends of the front plate 21, the rear plate 51, and the pair of left and right side plates 31, 41, and the peripheral walls 62a, 62b, 62c, and 62d of the cover plate 61 prevent the upper ends of the front plate 21, the rear plate 51, and the pair of side plates 31, 41 from opening outward, completing the assembly. In this assembled state, the measuring chamber is in a sealed state, as shown in Fig. 1. In this state, the front closing plate 34 of the right side plate 31 abuts against the inner surface of the front plate 21, and then the closing plate 35 abuts against the outer surface of the rear plate 51, preventing air from flowing in from the side, resulting in a satisfactory sealed state.

[0027] In the assembled state, the pair of left and right side plates 31, 41 are slidable while being guided by the guide grooves 56a, 56b, respectively, and can be opened and closed by gripping the handles 32. While upward force is likely to be generated on each side plate 31, 41 during this sliding operation, this force is suppressed by the cover plate 61, preventing the side plates 31, 41 from disengaging from the corresponding guide grooves 56a, 56b. Furthermore, the cover plate 61 does not come off because the engaging protrusions 65c, 65d engage with the engaging holes 54a, 54b of the rear plate 51 and the engaging protrusions 65a, 65b engage with the engaging holes 24a, 24b of the front plate 21. Even if an outward force is generated on each side plate 31, 41 during sliding, the supporting portions 57a, 57b of the rear plate 51 and the peripheral walls 62b, 62d of the cover plate 61 absorb this force, ensuring a smooth sliding movement.

[0028] 1 and 2, the front closing plate 34 of each side plate 31, 41 abuts against the inner surface of the front plate 21, and the rear closing plate 35 abuts against the outer surface of the rear plate 51, thereby shielding the measuring chamber. On the other hand, as each side plate 31, 41 is slid toward the rear plate 51 from the state shown in FIGS. 1 and 2, it gradually opens, and in the appropriate open state, a sample can be placed on the measuring pan from the desired side plate 31, 41. Furthermore, as each side plate 31, 41 slides, the opening gradually increases. However, when the front closing plate 34 abuts against the inner surface of the rear plate 51, the sliding of each side plate 31, 41 is stopped, preventing each side plate 31, 41 from falling off.

[0029] Furthermore, even if dust accumulates in the measuring chamber, the base 11 has no grooves, so the dust can be easily and reliably swept out.

[0030] The present invention is not limited to the above-described embodiment. For example, the lower ends of the side plates 31, 41 may be in a non-contact state away from the lower guide surfaces 14, 15 and not be guided by the lower guide surfaces 14, 15. The member for gripping the cover plate 61 is not limited to the through hole 66, and may be an appropriate number of gripping pieces. Furthermore, the protrusions 16a, 16b, 17a, 17b improve the shielding performance by abutting the lower ends against the vertical surfaces 14b, 15b of the lower guide surfaces 14, 15 when the side plates 31, 41 are closed, but the necessary shielding performance can be ensured even without the protrusions 16a, 16b, 17a, 17b. [Explanation of symbols]

[0031] 1. Electronic balance 2 Main unit case 10 Windshield 11 Base 12 Fixed plate 13a, 13b screw holes 14,15 Lower guide surface 16a,16b,17a,17b protrusion 18 Upper frame 19a,19b,19c,19d Locking part 21 Front panel 22a, 22b Notched step 23a,23b Through hole 24a,24b Engagement hole 25a, 25b Guide recess 31 Right side plate 32 Handle 33 Engagement plate 34 Anterior occlusion plate 35 Posterior occlusion plate 41 Left side plate 44 Engagement plate 51 Rear plate 52a, 52b Notched step 53a,53b Through hole 54a,54b Engagement hole 55a, 55b Guide recess 56a, 56b Guide groove 57a,57b Support part 58a,58b,58c,58d Stepped section 61 Lid plate 62a,62b,62c,62d Peripheral wall 63a, 63b, 63c, 63d Notch 64a,64b Locking protrusion 65a,65b,65c,65d Engagement protrusion 71a, 71b, 71c fixing screws

Claims

1. A windshield comprising a base, a front plate, a rear plate, a pair of side plates, and a cover plate, which are arranged on a main body case of an electronic balance to form a weighing chamber on the main body case, The front plate and the rear plate are fixed to the base, guide grooves are formed on both sides of the rear plate; Each of the pair of side plates is provided with an engaging protrusion that engages with the corresponding guide groove, and the engaging protrusion is guided by the guide groove, thereby slidably supporting the pair of side plates on the side ends of the rear plate, The cover plate has cutouts that allow the pair of side plates to slide, and is engaged with the upper ends of the front plate, the rear plate, and the pair of side plates. A windshield for an electronic balance characterized by the above.

2. The guide grooves are formed obliquely downward from the side edges on the upper portion of the rear plate, and the engaging protrusions are plate-shaped protrusions extending in the width direction on the upper portion of each side plate.

2. The windshield for an electronic balance according to claim 1.

3. Each of the side panels is provided with a front blocking portion that contacts the inside of the front panel to block the inflow of air from the outside when slid most toward the front panel, and a rear blocking portion that contacts the outside of the rear panel to block the inflow of air from the outside.

3. The windshield for an electronic balance according to claim 1 or 2.

4. The cover plate is provided with a stopper portion around its periphery to prevent the upper portions of the front plate, the rear plate, and the pair of side plates from opening outward.

3. The windshield for an electronic balance according to claim 1 or 2.

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