Weight scales and strain gauge assemblies useable therein

• US 4,691,794 A
• Filed: 09/04/1984
• Issued: 09/08/1987
• Est. Priority Date: 10/19/1983
• Status: Expired due to Term

• Current Assignee: Management Investment & Technology Company Limited
• Original Assignee: Fyrnetics Incorporated
• Inventors: Larsen, Larry D., Yung, Richard C. S., Hogel, Joseph E., Leung, Wing K.
• Primary Examiner(s): Miller, Jr., George H.
• Application Number:
  US06/689,377
• Time in Patent Office: 1,099 Days
• Field of Search: 177/177, 177/180, 177/211, 177/244, 177/255, 177/DIG. 9, 73/862.65, 73/862.66
• US Class Current: 177/211
• CPC Class Codes: G01G 3/1402 Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
• CPC Class Codes: Y10S 177/09 Scale bearings

Abstract

A strain gauge assembly of the type having an elongate flexible member (12) with attached strain gauges (36, 38) has forces applied thereto at points (48, 50) spaced from its central neutral plane (52) by means including members mounted to a foot (10) and force receiving (14) members for non-sliding lateral movement relative thereto. In another embodiment strain gauges are attached to a flexible diaphragm (68) which is in communication with a fluid contained within a flexible sealed container (78) that is restrained against lateral movement by a hollow restraint member (62) therearound but which has a portion (80) protruding from a lower open end (66) thereof to receive a load to pressurize the fluid for flexing the diaphragm (68). A weight scale suitable for employment of the above strain gauge assemblies has an electronic adder (91) summing the loads of a plurality of strain gauge assemblies (92) or load modules to produce a total load signal which is applied to an electronic display (90) for provision of a visual indication of weight.

Claims

1. In a weight scale having a housing and a display responsive to a strain gauge signal for visually indicating weight measured by the scale, an improved strain gauge assembly, comprising:

a flexible member with a strain gauge attached thereto to provide an electrical signal in response to the flexing of the flexible member;

a foot member in underlying relationship with the flexible member;

a load receiving member in overlying relationship with the flexible member;

a pair of support members connected with the foot member for supporting the flexible member at a pair of spaced locations associated therewith; and

a pair of load transmitting members connected with the load receiving member for transmitting a load therefrom to the flexible member at two locations spaced from one another and from the pair of locations associated with the foot member, at least one of said support members and load transmitting members having one end pivotally connected to the flexible member to pivot at a fixed location thereof and another end connected to the associated one of the foot member and load receiving member for relative lateral movement with respect thereto.

2. The weight scale of claim 1 in which said movement is translational lateral movement.

3. The weight scale of claim 1 in which said relative movement is non-sliding movement.

4. The weight scale of claim 3 in which said relative movement is rocking movement.

5. The weight scale of claim 1 in which

one of said support members is mounted for movement relative to the foot member, and

one of the load transmitting members is mounted for movement relative to the load receiving member.

6. The weight scale of claim 5 in which one of said support members is fixedly attached to the foot member.

7. The weight scale of claim 5 in which one of said load receiving members is fixedly attached to the load receiving member.

8. The weight scale of claim 1 in which one of said support members and load receiving members has a relative narrow connection portion engageable with the flexible member at a fixed location thereof and a base portion connected to its associated foot or force receiving members for relative movement therealong.

9. The weight scale of claim 8 in which said base portion has an arcuate surface for rolling translational movement.

10. The weight scale of claim 9 in which said base portion is fixedly mounted to the connection portion and said rolling motion imparts a pivotal motion to said connection portion.

11. The weight scale of claim 8 in which said base portion has a rocker surface for rocking movement.

12. The weight scale of claim 8 in which one of said support members and one of said loading transmitting members have a base portion with a rocker for rocking movement thereof.

13. The weight scale of claim 10 including means connected with the load receiving member, flexible member and foot member for retaining them together in the absence of a load.

14. The weight scale of claim 13 in which said retaining means includes a plurality of straps for holding the flexible member to the foot member and the load receiving member, respectively, in the absence of a load.

15. The weight scale of claim 13 in which

said flexible member has grooves in a surface thereof, and

said retaining means includes a plurality of straps which fit into the grooves, respectively, to retain the flexible member, foot member and load receiving members against substantial relative lateral movement in the absence of a load.

16. The weight scale of claim 1 in combination with

another improved strain gauge assembly substantially identical to said first mentioned strain gauge assembly contained with the housing,

a circuit responsive to the strain gauge signals from both of the strain gauge assemblies for producing a weight signal representative of the total load applied thereto, and

means for applying the weight signal to the display to provide an indication of the total weight.

17. In a weight scale having a housing and a display responsive to a strain gauge signal for visually indicating weight measured by the scale, an improved strain gauge assembly, comprising:

a flexible member with a strain gauge attached thereto to provide an electrical signal in response to the flexing of the flexible member;

a foot member in underlying relationship with the flexible member;

a load receiving member in overlying relationship with the flexible member;

a pair of support members connected with the foot member for supporting the flexible member at a pair of spaced locations associated therewith;

a pair of load transmitting members connected with the load receiving member for transmitting a load therefrom to the flexible member at two locations spaced from one another and from the pair of locations associated with the foot member; and

means connected with the load receiving member, flexible member and foot member for retaining them together in the absence of a load, said retaining means including

a plurality of retaining members,

one of said retaining members being attached to the load receiving member and engaging the flexible member adjacent one of the load transmitting members, and

another of said retaining members being attached to the foot member and engaging the flexible member adjacent one of support members.

18. The weight scale of claim 17 including

another retaining member attached to the load receiving member and engaging the flexible member for holding it thereto adjacent the other load transmitting member, and

another retaining member attached to the foot member and engaging the flexible member for holding it thereto adjacent the other support member.

19. A strain gauge assembly, comprising

a foot member;

a load receiving member;

a flexible member with a strain gauge attached thereto; and

means for interconnecting the flexible member with the foot member and the load receiving member including a rigid interconnecting member movably mounted between the flexible member and at least one of the foot member and the load receiving member for lateral movement relative thereto, said interconnecting member having

a relatively narrow end pivotally connected to the flexible member at a fixed connection point thereon at a preselected fixed distance from the strain gauge, and

another end for laterally moving along the surface of the at least one of the foot member and the load receiving member to which it is connected in response to relative lateral movement of the fixed connection point during bending of the flexible member in response to application of a load.

20. The strain gauge assembly of claim 19 in which said interconnecting means includes another interconnecting member spaced from said movably mounted interconnecting member and in engagement with said elongate flexible member and said at least one of the foot member and the load receiving member to which is connected the movably mounted interconnecting member.

21. The strain gauge assembly of claim 20 in which said other interconnecting member is fixedly mounted to the one of said foot member and load receiving member to which is connected said movably mounted interconnecting member.

22. The strain gauge assembly of claim 19 in which said movably mounted interconnecting member is mounted to the foot member for rocking movement relative thereto.

23. The strain gauge of claim 19 in which said movably mounted interconnecting member is mounted to said load receiving member for rolling movement relative thereto.

24. The strain gauge of claim 19 in which said flexible member has a slot at said fixed connection point for receipt of said relatively narrow end of the movably mounted interconnecting member.

25. The strain gauge assembly of claim 24 in which said other end of the interconnecting member has an arcuate surface for rolling lateral movement.

26. The strain gauge assembly of claim 19 in which said interconnecting member is a vertical load transmitting member which interconnects the load receiving member and the flexible member to transmit a load to said elongate flexible member from the load receiving member.

27. The strain gauge assembly of claim 26 including another vertical load transmitting member which is fixedly mounted to one of said load receiving member and said flexible member and spaced from said movably mounted load transmitting member by a preselected amount greater than said preselected distance.

28. The strain gauge assembly of claim 27 including another vertical support member which is fixedly mounted to one of said foot member and the flexible member and spaced from said movably mounted support member by a preselected amount greater than said preselected distance.

29. The strain gauge assembly of claim 25 including another load transmitting member spaced from said movably mounted load transmitting member by another preselected amount less than said preselected amount.

30. The strain gauge assembly of claim 29 in which said support members are located between said load transmitting members.

31. The strain gauge assembly of claim 30 in which the movably mounted support member is mounted adjacent said fixedly mounted load transmitting member.

32. The strain gauge assembly of claim 26 in which said movably mounted load transmitting member is mounted to the foot member for rocking movement relative thereto.

33. The strain gauge assembly of claim 25 including another movably mounted load transmitting member interconnecting the load receiving member and the flexible member and mounted to the load receiving member for non-sliding movement relative thereto.

34. The strain gauge assembly of claim 33 in which said movably mounted load transmitting member is mounted to the load receiving member for rocking movement relative thereto.

35. The strain gauge assembly of claim 33 in which movably mounted load transmitting member is mounted to the flexible member for pivotal movement relative thereto.

36. The strain gauge assembly of claim 35 in which said movably mounted load transmitting member is mounted to the load receiving member for rocking movement relative thereto.

37. The strain gauge assembly of claim 33 in which said flexible member has a central plane extending therethrough and all of said support members and said load transmitting members are mounted to slots of said flexible member which extend to a location spaced from said plane.

38. The strain gauge of claim 19 in which said interconnecting member is a support member which interconnects the flexible member and the foot member and supports the flexible member against a vertical load above the foot member.

39. The strain gauge assembly of claim 19 in which said flexible member has a central plane and said movably mounted interconnecting member is engaged therewith at a location spaced from said plane.

40. The strain gauge assembly of claim 39 in which said flexible member has a notch extending therein to a preselected distance from said central plane and said interconnecting member is received within said notch.

41. The strain gauge assembly of claim 19 including a second strain gauge attached to said flexible member opposite said first mentioned strain gauge.

42. The strain gauge assembly of claim 19 in combination with a meter for producing an indication of the amount of strain imposed on said strain gauge.

43. A strain gauge assembly, comprising:

a foot member;

a flexible member overlying said foot member having

a pair of opposite horizontal upper and lower surfaces substantially equidistant from a central horizontal neutral plane thereof,

a first notch extending upwardly away from said foot member into the lower one of said surfaces to within a non-zero preselected distance from said central plane, and

a second notch extending downwardly toward said foot member into the other of said surfaces to within another non-zero preselected distance from said central plane;

a strain gauge mounted to one of said horizontal surfaces;

a support member underlying the flexible member and mounted to said foot member and extending into said first notch to support said flexible member at said one non-zero preselected distance from the central neutral plane intermediate the lower one of said surfaces and the central plane; and

means directly unidirectionally transmitting a vertically directed load to said flexible member including

a force receiving member in overlying relationship with said flexible member and said foot member, and

a force transmitting member mounted to said force receiving member and extending downwardly into said second notch to transmit vertical force received by the force receiving member directly to the flexible member at said other non-zero preselected distance from the central neutral plane intermediate the upper one of said surfaces and the central plane.

44. The strain gauge assembly of claim 43 in which

said flexible member has

a third notch extending upwardly into the lower one of said horizontal surfaces to within said one preselected non-zero distance from said central plane, and

a fourth notch extending downwardly into the upper one of said upper surface to within said other preselected non-zero distance from the central neutral plane, and including

a second support member mounted to said foot member and extending upwardly into said third notch to support the flexible member at said one preselected non-zero distance from the central neutral plane, and in which

said load transmitting means includes a second force transmitting member mounted to an under surface of said force receiving member and extending downwardly into said fourth notch to directly transmit downward force received by the force receiving member to the flexible member at said other preselected non-zero distance from the central plane.

45. The strain gauge assembly of claim 44 in which

the second and fourth notches are spaced from one another by a first preselected distance,

said first and third notches are separated from one another by a second preselected distance which is less than said first preselected distance, and

said one and the other preselected distances from the central plane are equal to each other.

46. The strain gauge assembly of claim 45 in which the first and second notches are separated from one another by a third preselected distance and the third and fourth notches are separated from one another by a fourth preselected distance which is substantially equal to said third preselected distance.

47. The strain gauge assembly of claim 46 in which the strain gauge is mounted to the one horizontal surface between the first and third notches.

48. The strain gauge assembly of claim 47 including a second strain gauge mounted to the other of said horizontal surfaces opposite said first mentioned strain gauge.

49. In a weight scale having a housing, a power supply and a weight indicator responsive to a strain gauge, the improvement being a self-contained strain gauge module mounted within the housing, comprising:

an elongate force receiving member having an open face opposite a main horizontal wall between a pair of spaced, downwardly extending sidewalls;

an elongate frame member having an open face opposite a main horizontal wall between a pair of upwardly extending sidewalls;

an elongate flexible member with a strain gauge attached to a horizontal surface thereof for measuring flexing in a vertical plane; and

means connected with the main walls of the frame member and force receiving member for mounting the flexible member in force receiving relationship therebetween and for protection thereof by both of said pairs of sidewalls, said sidewalls overlapping to protectively contain the flexible member therebetween in adjacent parallel relationship therewith when mounted in force receiving relationship between the main walls, said mounting means including

a pair of spaced, rigid support members connected between the frame member for supporting the flexible member sufficiently above the main wall of the frame at a pair of spaced locations to enable downward flexing when weight is applied to the main wall of the force receiving member,

a pair of spaced, rigid force transmitting members connected between the flexible member and the frame receiving member for supporting the force receiving member above the main wall of the force receiving member at two spaced locations to directly transmit a vertical weight load from the main wall of the force receiving member to the flexible member at said two locations to cause flexing of the flexible member.

50. The strain gauge assembly of claim 49 in which the pair of sidewalls of one of said frame member and the force receiving member is slideably received between the pair of sidewalls of the other of said frame member and the force receiving member.

51. The strain gauge assembly of claim 49 in which the elongate sidewalls of the frame member are between and adjacent the elongate sidewalls of the force receiving member and adjacent elongate sidewalls of the flexible member.

52. The strain gauge assembly of claim 49 in which each of said frame member and force receiving member have a second pair of sidewalls at the end thereof which interconnect and extend in a direction transverse to the elongate sidewalls.

53. The strain gauge assembly of claim 49 including a switch connected with the strain gauge and mounted to one of said frame member and force receiving member and protectively enclosed therebetween.

54. The strain gauge assembly of claim 53 in which said switch is actuated by relative vertical movement between the frame member and the force receiving member.

55. A strain gauge sub-assembly, comprising:

an elongate, flexible rectangular member having a relatively wider pair of surfaces equidistant from a central neutral plane thereof and a relatively narrower pair of surfaces interconnecting the relatively wider surfaces;

a strain gauge mounted to one of said pair of relatively wider surfaces, and

a pair of notches in each of said pair of relatively wider surfaces extending into the flexible member to a non-zero preselected distance from the central neutral plane.

56. The strain gauge sub-assembly of claim 55 in which said notches have a substantially V-shaped cross section.

57. The strain gauge sub-assembly of claim 55 in which the distance between the pair of notches of one of said pair of surfaces is greater than the distance between the notches of the other of said pair of surfaces.

58. The strain gauge sub-assembly of claim 55 in which said pairs of notches are symmetrically located with respect to the elongate center of the flexible member.

59. The strain gauge assembly of claim 55 in which all of said preselected distances are equal to each other.

60. The strain gauge sub-assembly of claim 55 including another strain gauge mounted to the other of said relatively wider pair of surfaces opposite the first mentioned strain gauge.

61. In an electric weight scale having a housing and a display mounted to the housing for providing a visual indication of weight, the improvement comprising:

a plurality of separate self contained load modules contained within the housing and each of which includes a strain gauge for sensing weight, each of said modules including its own switch actuated only in response to receipt of a weight thereby to enable provision of a visual indication of weight,

an electric adder connected with each of the strain gauges of said plurality of load modules for producing a total weight signal proportional to the total weight sensed by the strain gauges; and

means for connecting the total weight signal to the display to cause visual display of the total weight represented thereby.

62. In an electric weight scale having a housing and a display mounted to the housing for providing a visual indication of weight, the improvement comprising:

a plurality of separate self contained load modules contained within the housing and each of which includes a strain gauge for sensing weight, said plurality of load modules including two load modules located alongside one another and spaced a distance from one another by a distance substantially equal to the distance between a person'"'"'s feet when standing normally, each one of said two load modules providing a weight signal in response to the force applied thereto by one foot independently of the force applied by the other foot to the other module,

an electric adder connected with each of the strain gauges of said plurality of load modules for producing a total weight signal proportional to the total weight sensed by the strain gauges; and

means for connecting the total weight signal to the display to cause visual display of the total weight represented thereby.