IE43341B1 - A spring balance for domestic or other use - Google Patents

Abstract

1491116 Spring balance MURRHARDTER WAAGENFABRIK Gebr SOEHNLE 30 Sept 1975 [3 Oct 1974] 40032/75 Heading G1W A spring balance comprises a removable pan 4, and housing upper and under parts 2, 1 which are circular in plan view and which are attached at their peripheries by means forming a ledge to receive the inverted pan leaf springs 22, 22' inter-connecting spring carriers 19, 20 one spring carrier 19 being mounted on a pedestal 16 secured to the housing underpart and the other spring carrier 20 being connected to a pan carrier 6 which has a depending annular flange which overlaps the upper edge of an upwardly extending neck of the housing upper part, and an indicating mechanism including a pointer pivoted about a vertical axis for movement over a horizontal scale and a lever arrangment coupling the pointer to the other spring carrier 20, the leaf springs and spring carriers being constructed as a completed assembly 3 prior to installation in the housing. A member 5 is attached to spring carrier 20, and the pan carrier 6 is supported on member 5. Pan carrier 6 has two guide pins 25 co-operating with guiding and locking apertures 29, Fig. 4, in the member 5, and a rectangular locking member 27 co-operating with a rectangular aperture 28 in member 5. The completed assembly 3 further includes the indicating mechanism. A bracket 32 is fixed to spring carrier 19 and a lever 33 is pivotally mounted on bracket 32 at 34. The lever 33 includes at one end a nose 35 engaging the other spring carrier 20, and at the other end engages a rack 41 via a knife edge pivot. The nose 35 is resiliently mounted and is adjusted relative to pivot axis 34 by a screw to adjust the balance sensitivity. The bracket 32 includes an angle portion 48, Fig. 3, on which a lever 43 is pivoted at 49. Lever 43 includes an aperture 46 within which a pinion 44 is rotatably mounted, the pinion being engaged with the rack 41 and having a shaft 54 which drives a pointer 11. The rack 41 is guided by one edge of the aperture 46. The lever 43 is biased by a spring 50 against a zero adjustment screw 51 mounted on a bracket 53. The pointer co-operates with a fixed scale 10 in the housing under part and is viewed through a window 13 in the housing upper part. The window 13 carries a further scale and the upper part 2 rotates relative to the lower part 1 to facilitate weighing additional amounts. The pan 4 may be placed underneath the housing to support the balance when weighing bulky loads.

Description

This invention relates to a spring balance, for domestic i or other use, (herein called a spring balance as first specified) comprising a removable pan, a multi-part housing, and a mechanism which is constructed as a complete assembly unit prior to being installed in the housing, the said mechanism comprising two or more leaf springs which are parallel to and spaced from each other and first and second spring carriers to which the ends of the leaf springs are fastened, the first spring carrier being secured to an under part of the housing, the balance further comprising a movable pan carrier connected to the second spring carrier and a lever arrangement coupled to the second spring carrier and comprising a pointer mounted to pivot about a vertical axis and indicate in relation to a horizontal scale, the pivoting motions of the pointer being dependent upon loadcaused deflections of the leaf springs, the said housing also comprising an upper part which is connected to the said under part and covers the mechanism.

The invention is intended to facilitate the provision of a balance as first specified which can be convenient to assemble and to use and store.

According to the invention a balance as first specified is characterised in that the said housing upper part and under part are circular in plan view, the under part is provided with 3 3 41 a pedestal to which the first spring carrier is secured, the housing upper part has an upwardly extending neck with a top edge which is overlapped by and inwardly spaced from a depending annular flange of the pan carrier, and the housing upper part and under part are attached to one another at their peripheries by attachment means forming a circumferential ledge on which the rim of the pan can rest when the pan is inverted for the balance to be stored.

How the invention may be put into practice is explained in greater detail with reference to the accompanying drawings, wherei n: Figure 1 shows a partial section through a spring balance in accordance with the invention, Figure 2 shows an elevation of a mechanism, Figure 3 shows a lateral elevation in the direction of the arrow III in Figure 2, Figure 4 shows a plan view in the direction of the arrow IV in Figure 2, a Figure 5 shows an elevation of/lever arrangement, and Figure 6 shows a lateral elevation in the direction of the arrow VI in Figure 5.

In the spring balance illustrated in section in Figure 1, is a housing comprising a housing under part 1 of dish-like formation and a housing upper part 2. A mechanism 3 (see also Figures 2 to 6) forms a complete assembly unit prior to being installed in the housing. The mechanism 3 comprises a first spring carrier 19 which is firmly connected to a pedestal 17 in the housing under part 1. The mechanism 3 also includes 433 41 an angle plate 5. After the mechanism 3 is installed a pan carrier 6 is placed upon angle plate 5 and supports a removable pan 4 which receives the material to be weighed. Ihe pan 4 has a downwardly extending annular formation 7 and is thereby retained against lateral shifting on the pan carrier 6.

To facilitate the weighing of bulky pieces, the housing under part 1 can be inserted from above into the pan 4 when the latter stands upon a table or other support. Then, as indicated in dot-and-dash lines on the lower right in Figure 1, a circumferential ledge 8 rests on the rim of the pan 4. The housing under part 1 and the housing upper part 2 form the circumferential ledge 8, and the housing upper part 2 also forms a circumferential ledge 9 on which the rim of the pan 4 can rest when the pan 4 is in the inverted condition, as indicated i in Figure 1 in dotted lines at the right.

The mechanism 3 includes a pointer 11 (Figures 3 and 4).

A weight scale 10, over which the tip of the pointer 11 moves, is firmly connected with the housing under part 1. This weight scale 10 is visible through an elongated viewing window ι 12 let into the housing upper part 2. The housing upper part 2 is rotatably arranged on the housing under part 1, and in the viewing window 12 there is an additional upper weight scale 13, which can be printed directly on the viewing window 12.

By rotation of the housing upper part 2 it is possible to bring the zero.point of the upper weight scale 13 into the zero position with the pointer 11 in each of a series of weighing operations, in order thus to be able to determine the weights of additional loads without calculation. At the same time the total weight of the loads can be read from the weight scale 10.

The mechanism 3, which is constructed as a complete assembly unit prior to being inserted into the housing under part 1, has its first spring carrier 19 secured to the pedestal 17 in the housing under part 1 by means of two screws 14 provided with washers 15 and extending through slots 16 in the pedestal 17.

The mechanism 3 is illustrated alone in Figures 2 to 4 in various views, and it includes a spring arrangement 18 comprising the first spring carrier 19 and a second spring carrier 20. The two spring cariers 19 and 20 are of U-shaped crosssection, 'ith lens 21 which are interconnected through two upper leaf springs 22 and two lower leaf springs 22' respectively. The web 23 of the first spring carrier 19 is firmly secured by the said screws 14 to the pedestal 17 of the housing under part 1, whereas the angle plate 5 for supporting the pan carrier 6 is secured to the web 24 of the second spring carrier 20. The pan carrier 6 comprises two journal-like projections 25 and a headed locking part 27 with a cylindrical stem 26. In the angle plate 5 (Figure 4) is a piercing 28 through which the locking part 27 extends and there are slots 29 to co-operate with the projections 25. The slots 29 extend approximately along arcs of a circle and taper over their longitudinal extents, so that when the locking part 27 is pushed through the piercing 28 and the projections 25 are pushed into the slots 29 J3341 there is sufficient clearance, and locking takes place when the pan carrier 6 is rotated on the angle plate 5. The slots 29 are provided with end detent widenings 30 in order to make unlocking more difficult. In the locked condition the head of the locking part 27 engages under the angle plate 5.

On loading of the angle plate 5 by means of the pan carrier 6 or the pan 4, the second spring carrier 20 descends in proportion to the load resulting in deformation of the leaf springs 22, 22', and this descent actuates a lever arrangement 31. A bracket 32 (Figure 2) is secured by screws to the inner side of the web 23 of the spring carrier 19. On one arm of the bracket 32 is a two-armed pivot lever 33 (Figures 2 and 5) mounted for pivoting about a pivot axis 34. This two-armed pivot lever 33 has a nose 35 which rests on a support surface 36 of the lower leg 21 of the spring carrier 20. The plane of alignment 37 (Figure 2) of the support surface 36 is arranged so that when the spring balance is unloaded this plane 37 extends above the pivot axis 34, whereas when the spring balance is loaded the plane 37 extends beneath the pivot axis 34. If the floating plane passes through the pivotal axis at about half the maximum loading, the maximum error of the indicator over the whole range is a minimum. Thus any deviation of the indicated weight from the actual load weight can be kept small over the entire weighing range.

For adjustment of the indicated proportionality, the pivot lever 33 is provided with a resilient leg 38 having adjusting screw 39 by which the nose 35 is displaceable along a line 40 (Figure 5) passing through the pivot axis 34. Thus the effective length of the two-armed lever 33 between the second spring carrier 20 connected with the pan carrier 6 and the pivot axis 34 of the said lever is adjustable.

At the end of the pivot lever 33 opposite to the nose 35 is a knifeedge mounting 42 (Figure 5) engaging a rack 41 which meshes with a pinion 44 (Figure 6) mounted in a pinion-bearing lever 43. The rack 41 is loaded by a tension spring 45. Pinion 44 is mounted in the lever 43 in an aperture 46 of which one boundary surface 47 guides the rack 41. The pinion 44 is secured to a pinion shaft 54.

The lever 43 pivots about a spindle 49 on an angled-off leg 48 of the bracket 32, and a spring 50 (Figure 2) pulls the lever 43 against tbe end of a calibrating screw 51. The calibrating screw 51 is guided for screwing in a bearing 52 on a sheet metal tongue 53. The sheet metal tongue 53, to which one end of the spring 50 is also hooked, is secured by screws to the web 23 of the spring carrier 19 (Figure 2). For zero point setting, or calibration of the balance, the lever 43 can be pivoted about the axis 49 of the angled-off leg 48 of the bracket 32 by means of the calibrating screw 51. The pinion 44 then moves in relation to the rack 41 and effects a correction of the weight indication by means of the pointer 11, which is secured to the pinion shaft 54 (Figure 3).

In order to reduce friction, the pinion shaft 54 is supported at the end by a guide plate 55 (Figure 3). It may be noted that the pinion-bearing lever 43 and the rack 41 are approximately perpendicular to one another, while the rack 41 and the calibrating screw 51 are substantially parallel to one another.

To prevent overloading of the spring balance an inner edge surface 56 of the housing upper part 2 is placed so that when the limit load is reached the pan carrier 6 engages the edge surface 56 and the spring mechanism cannot be loaded any further.

The housing upper part 2 is rotatably guided on the housing under part 1, the upper part 2 having resilient projections 58 which engage below an annular bead 57 on the lower part 1 (Figure 1).

In this preferred construction the mechanism 18 and the lever arrangement 31 are completely assembled together before being introduced into the housing upper part 1 and secured to the pedestal 17.

Claims (26)

1. A spring balance as first specified herein, characterised in that the said housing upper part and under part are circular in plan view, the under part is provided with a pedestal to which the first spring carrier is secured, the housing upper part has an upwardly extending neck with a top edge which is overlapped by and inwardly spaced from a depending annular flange of the pan carrier, and the housing upper part and under part are attached to one another at their peripheries by attachment means forming a circumferential ledge on which the rim of the pan can rest when the pan is inverted for the balance to be stored.

2. A balance according to claim 1, wherein the housing upper part is rotatable relative to the under part.

3. A balance according to claim 1 or 2, wherein the said attachment means consist of resilient projections on the housing upper part engaging under an annular edge bead on the housing under part.

4. A balance according to claim 1, 2 or 3, wherein the said pedestal projects vertically upwards from the bottom of the housing under part.

5. A balance according to claim 4, wherein the pedestal has slots through which the shanks of headed screws extend into the first spring carrier so that the latter is adjustably secured to the pedestal. 4 3 3 41

6. A balance according to any one of the preceding claims, wherein the said scale is secured to the housing under part, and the housing upper part has a window for viewing the scale. 7. A balance according to claim 6, wherein the window carri es a supplementary scale. 8. A balance according to any one of the preceding claims, wherei n the mechanism comprises a bracket which is secured to the first spring carrier and to which is pivotably connected a two-armed lever which engages and moves with the second spring carrier connected to the pan carrier, and motion from the two-armed lever is transmitted by a toothed rack and a pinion to the pointer.

7. 9. A balance according to claim 8, wherein the two-armed lever is spring-loaded and has a nose which rests on a support surface of a leg of the second spring carrier. 10. A balance according to claim 9, wherein the said surface lies in a plane which extends above the pivot axis of the two-armed lever when the balance is in the unloaded condition and extends below this pivot axis when there is maximum loading of the balance.

8. 11. A balance according to claim 10, wherein the said plane passes through the said pivot axis of the said lever when there is approximately half maximum loading of the balance.

9. 12. A balance according to any one of claims 8 to 11, wherein the effective lever arm of the two-armed lever between the second spring carrier connected with the pan carrier and the pivot axis of the said lever is adjustable.

10. 13. A balance according to claim 12 when dependent on any one of claims 9 to 11, wherein for the adjustment of the said effective lever arm the two-armed lever has a resilient leg having an adjusting screw by means of which the nose of the lever may be displaced along a line through the pivot axis of the said lever.

11. 14. A balance according to any one of claims 8 to 13, wherein the said bracket is secured to a web of the first spring carrier connected firmly with the housing under part.

12. 15. A balance according to any one of claims 8 to 14, wherein on the said bracket there is an angled-off leg on which a pinion-bearing lever bearing the said pinion is pivotably mounted and is pivotable against the action of a spring by means of a calibrating screw.

13. 16. A balance according to claim 15, wherein the calibrating screw is guided for screwing in a sheet metal tongue which is firmly connected with the first spring carrier connected to the housing under part.

14. 17. A balance according to claim 16, wherein one end the spring acting upon the pinion-bearing lever is connected to the sheet metal tongue.

15. 18. A balance according to claim 15, 16 or 17, wherein the pinion is secured to a pinion shaft and in the pinionbearing lever there is an aperture which accommodates the pinion, and the pointer is placed upon an end Dortion of the pinion shaft protruding downwards from the pinion-bearing 1 ever.

16. 19. A balance according to claim 18, wherein the end portion of the pinion shaft protruding downwards from the pinionbearing lever is supported by a guide plate.

17. 20. A balance according to claims 8 and 15, wherein the rack meshing with the pinion protrudes through an aperture in the pinion-bearing lever and one side boundary of this aperture serves to guide the rack.

18. 21. A balance according to claim 20, wherein the pinionbearing lever and the rack are approximately perpendicular to one another.

19. 22. A balance according to claims 14 and 21, wherein the calibrating screw and the rack are approximately parallel to one another.

20. 23. A balance according to claim 15, wherein at least the spring carriers with the leaf springs, the brackets, the two-armed lever, the rack, the pinion and the pinion-bearing lever constitute the said complete asssembly unit.

21. 24. A balance according to any one of the preceding claims, wherein an angle plate is secured to the second spring carrier to support the pan carrier, and a flat leg of the angle plate extends over the upper leaf springs, and the pan carrier is held in place on this flat leg by projections on the pan carrier extending through apertures in the flat leg. 4 3 3 41

22. 25. A balance according to claim 24, wherein said projections include at least two journal-like projections on the pan carrier, and at least two slots extending approximately along arcs of a circle are provided in the angle plate to cooperate with the journal-like projections.

23. 26. A balance according to claim 25, wherein each of the said slots is of tapered formation over its length and has a detent widening at its narrower end.

24. 27. A balance according to claim 25 or 26, wherein a locking part having a head on a cylindrical stem is provided on the pan carrier and in the angle plate there is a piercing through which the locking part extends.

25. 28. A balance according to any one of the preceding claims wherein the said attachment means forms a circumferential ledge which can rest on the rim of the pan when the latter stands on a table or like support so that in this condition it is possible to weight loads placed directly upon the pan carrier.

26. 29. A spring balance, for domestic or other use, construct ed and arranged substantially as hereinbefore described with reference to and as shown in the accompanying drawings.