Flat electronic scales

• US 6,211,472 B1
• Filed: 11/13/1998
• Issued: 04/03/2001
• Est. Priority Date: 12/19/1997
• Status: Expired due to Term

• Current Assignee: Sartorius Lab Instruments GmbH & Co. KG (Sartorius AG)
• Original Assignee: Sartorius AG
• Inventors: Meyer, Stefanie, Eger, Matthias, Schulze, Werner, Hirche, Steffen
• Primary Examiner(s): Gibson, Randy W.
• Application Number:
  US09/192,117
• Time in Patent Office: 872 Days
• Field of Search: 177/211, 177/229, 177/124, 177/154, 177/157, 177/158, 177/238, 73/862.627, 73/862.632, 73/862.634
• US Class Current: 177/154
• CPC Class Codes: G01G 21/244 combined with flexure-plate fulcrums flexure-plate fulcrums G01G21/07
• CPC Class Codes: G01G 23/005 Means for preventing overload
• CPC Class Codes: H01M 50/216 adapted for button or coin cells
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A top-loading balance with a housing, a weighing pan, and a load receptor, wherein the load receptor is connected with a system carrier by a parallel guidance having an upper guide and a lower guide. The system carrier is fixed relative to the housing. One of the guides is divided into two part-guides which, seen in plan view, are disposed preferably on either side of the undivided guide so that the guides do not overlap. In addition, the load receptor, the guides and the system carrier preferably form an integral component. The top-loading balance also includes strain gauges on at least one of the guides to generate a load-dependent electrical signal, which can be measured and converted into e.g. a visual display of the mass. The integral component has two cavities for batteries and the system carrier extends between the two battery cavities. Furthermore, the load receptor is constructed to be approximately U-shaped and the two limbs of the U are disposed laterally near the battery cavities. In addition, the strain gauges are arranged only on the inner side of the undivided guide. Therefore, the top-loading scale is flat and compact without compromising the stability of the scale. Preferably, the balance includes features, such as overload abutments, that protect the delicate parallel guidance, as well as features that ensure accurate measurement of off-center loads.

Claims

1. A top-loading scale, comprising:

a weighing pan to receive a load;

a housing;

an integral component having two cavities to receive two batteries, comprising;

a parallel guidance having an upper guide and a lower guide, wherein one of the guides is a divided guide split into two partial guides and the other guide is an undivided guide;

a system carrier fixed to the housing and extending between the two cavities; and

a load receiver being connected to the system carrier via the parallel guidance; and

strain gauges disposed only on an inner side of the undivided guide to generate an electrical signal dependent on the load on the weighing pan.

2. The top-loading scale of claim 1, wherein the load receiver has a U-shape with two limbs, the two limbs being disposed laterally next to the two cavities.

3. The top-loading scale of claim 1, wherein, in top plan view, the two partial guides are located on both sides of the undivided guide such that the divided guide and the undivided guide do not overlap.

4. The top-loading scale of claim 1, wherein the load receiver further comprises two slots to form two resilient arms having respective support points that support the weighing pan.

5. The top-loading scale of claim 1, wherein the housing comprises protrusions that form overload abutments for the weighing pan.

6. The top-loading scale of claim 5, wherein each of the two partial guides comprises a passage substantially in a center thereof through which a respective one of the protrusions extends.

7. The top-loading scale of claim 1, wherein the housing comprises two downwardly open battery compartments extending into the two cavities of the integral component, and wherein the two battery compartments form overload abutments for the weighing pan.

8. The top-loading scale of claim 2, wherein the housing comprises two downwardly open battery compartments extending into the two cavities of the integral component, and wherein the two battery compartments form overload abutments for the weighing pan.

9. The top-loading scale of claim 1, wherein the system carrier comprises a groove containing electrical leads that connect to the strain gauges.

10. The top-loading scale of claim 1, further comprising a common foil located on the inner side of the undivided guide, on which the strain gauges are arranged.

11. The top-loading scale of claim 10, wherein the inner side of the undivided guide comprises a step receiving an edge of the common foil, for positioning the strain gauges on the undivided guide.

12. The top-loading scale of claim 1, further comprising a detent system configured to fix the weighing pan to the housing when the weighing pan is laterally displaced out of a normal weighing setting.

13. The top-loading scale of claim 12, wherein the detent system comprises:

first latches mounted at the weighing pan;

second latches mounted at the weighing pan;

holes in the housing;

projections mounted at the housing;

protrusions on an underside of the weighing pan; and

recesses in the limbs of the load receiver,

wherein, when the weighing pan is fixed to the housing, the first latches of the weighing pan are locked in the holes of the housing, the second latches mounted at the weighing pan are latched behind the projections mounted at the housing, and the protrusions on the underside of the weighing pan are disposed in the recesses in the limbs of the load receiver.

14. An electronic scale for measuring the mass of a load, comprising:

a flat housing having overload abutments;

a system carrier connected to said housing, said system carrier lying substantially in a plane;

a load receptor disposed substantially in said plane;

parallel guides with strain gauges, said parallel guides connecting said load receptor to said system carrier, said parallel guides disposed substantially in said plane, and wherein said load receptor does not contact said housing under normal loads; and

a weighing pan resting on said load receptor, wherein said overload abutments extend through cavities in said parallel guides, and wherein said weighing p an rests on said overload abutments when said load exceeds a certain capacity.

15. The electronic scale of claim 14, wherein said system carrier has at least one battery cavity to receive a battery and wherein said battery is structured to provide a further overload abutment when positioned between said housing and said weighing pan.

16. The electronic scale of claim 14, further comprising a detent system configured to fix the weighing pan to the housing when the weighing pan is laterally displaced out of a normal weighing setting.

17. A top-loading scale, comprising:

a weighing pan that receives a load;

a housing having at least one overload abutment for the weighing pan; and

an integral component, comprising;

a load receptor;

a system carrier fixed to the housing; and

a parallel guidance having an upper guide and a lower guide, wherein one of the guides is divided into two partial guides and the other guide is an undivided guide; and

a plurality of strain gauges on an inner side of the undivided guide that generates an electrical signal dependent on the load on the weighing pan,

wherein the integral component has at least one cavity through which the overload abutment extends.

18. The top-loading scale of claim 17, wherein the parallel guidance has the at least one cavity through which the overload abutment extends.

19. The top loading scale of claim 17, wherein the housing has at least one downwardly open battery compartment, and the load receptor has at least one cavity that receives the battery compartment.

20. A top-loading scale, comprising:

a weighing pan that receives a load;

a housing;

an integral component, comprising;

a load receiver;

a system carrier fixed to the housing; and

a parallel guidance having an upper guide and a lower guide, wherein one of the guides is divided into two partial guides and the other guide is an undivided guide;

a plurality of strain gauges on an inner side of the undivided guide that generates an electrical signal dependent on the load on the weighing pan; and

a detent system configured to fix the weighing pan to the housing when the weighing pan is laterally displaced out of a normal weighing setting.

21. The top-loading scale of claim 20, wherein the detent system comprises:

first latches mounted at the weighing pan;

second latches mounted at the weighing pan;

holes in the housing;

projections mounted at the housing;

protrusions on an underside of the weighing pan; and

recesses in the limbs of the load receiver,

wherein, when the weighing pan is fixed to the housing, the first latches of the weighing pan are locked in the holes of the housing, the second latches mounted at the weighing pan are latched behind the projections mounted at the housing, and the protrusions on the underside of the weighing pan are disposed in the recesses in the limbs of the load receiver.