Weight sensor

• US 5,000,274 A
• Filed: 01/18/1990
• Issued: 03/19/1991
• Est. Priority Date: 01/19/1989
• Status: Expired due to Fees

• Current Assignee: K-Tron International, Inc. (Hillenbrand Incorporated)
• Original Assignee: K-Tron International, Inc. (Hillenbrand Incorporated)
• Inventors: Bullivant, Kenneth W.
• Primary Examiner(s): Miller, Jr., George H.
• Application Number:
  US07/467,516
• Time in Patent Office: 425 Days
• Field of Search: 177/128, 177/210 EM, 177/211, 73/862.69
• US Class Current: 177/210.0EM
• CPC Class Codes: G07G 1/0054 with control of supplementary check-parameters, e.g. weight or number of articles
• CPC Class Codes: G08B 13/1472 with force or weight detection

Abstract

A low profile weight sensor for a weight sensing system for monitoring article input and removal from article storage apparatus comprises a plate or I-shaped bar support member having first and second sections, an integrally formed linkage system for connecting the first and second sections such that the sections are substantially coplanar in an unloaded state, and are relatively displaceable with respect to each other in response to a weight load applied to one of the sections; and a magnetic transducer mounted on surfaces extending in the thickness direction of the plate/bar member for producing an electrical output signal responsive to relative displacement of the first and second sections. In a multiple weight sensor embodiment, a planar support member has a plurality of such weight sensing portions, and each weight sensing portion is isolated by a continuous slot such that all of the second sections of the weight sensing portions are connected together to a common framework by a single, relatively narrow, tongue section associated with each weight sensing portion. Mounting of the magnetic transducer is facilitated by the use of an adhesive which is relatively viscous during a setting time; and by a pair of bracket mounting guide members configured to prevent tilting of a magnetic field sensor mounted thereon, while permitting longitudinal displacement thereof; and to permit transverse displacement of magnetic field generating elements mounted thereon in the thickness direction of the support member.

Claims

1. A low profile weight sensor comprising:

support means including a planar portion having a thickness and first and second sections;

first and second spaced flexible linkage means for connecting said first and second sections such that said first and second sections are substantially coplanar in an unloaded state, and are relatively displaceable with respect to each other in response to weight load applied to one of said sections; and

transducer means for producting an electrical output signal responsive to relative displacement of said first and second sections;

said support means planar portion including a continuous slot formed therein and connecting said first and second linkage means, said slot defining said first and second sections and first and second mounting surfaces on -aid first and second sections, respectively;

said first and second mounting surfaces extending in the thickness direction of said planar portion and being spaced from each other in a direction transverse to the thickness direction;

said transducer means comprising means for generating a magnetic field fixedly secured to said first mounting surface and means for sensing the magnitude of said magnetic field fixedly secured to said second mounting surface.

2. The weight sensor of claim 1 wherein said first and second linkage means each comprises a plurality of parallel link members connected by flexible joint portions formed in said planar portion.

11. The weight sensor of claim 1 wherein:

I-shaped bar means having two flange portions joined by a planar central web portion, and a first section and at least one second section, constitutes said support means;

linkage means formed in each of said flange portions constitute said first and second flexible linkage means;

and said transducer means is mounted on said web portion.

12. The weight sensor of claim 11 wherein each of said flange linkage means comprises a slot formed in the associated flange portion so as to define two relatively flexible links parallel to a longitudinal center line of said bar means, said slot extending into said central web portion and having a thickness at least equal to a thickness of said web portion so as to isolate said links from said web portion.

13. The weight sensor of claim 12 further comprising a further slot constituting said continuous slot formed in said central web portion and connecting the flange portion slots;

and wherein said transducer means comprises means for generating a magnetic field fixedly secured to a first one of said first and at least one second sections and means for sensing the magnitude of said magnetic field secured to a second one of said first and at least one second sections proximate said magnetic field generating means; and

wherein said further central web portion slot defines first and second spaced mounting surfaces on said first and at least one second sections, respectively, said first and second mounting surfaces extending in the thickness direction of said central web portion;

said magnetic field generating means being secured to one of said first and second mounting surfaces and said magnetic field sensing means being secured to another one of said first and second mounting surfaces.

14. The weight sensor of claim 13 further comprising first bracket mounting guide means for positioning of said magnetic field sensing means in alignment with said longitudinal center line of said bar member.

15. The weight sensor of claim 14 wherein said first bracket mounting guide means includes retaining means for preventing tilting of said magnetic field sensing means while permitting transverse displacement thereof relative to said longitudinal center line when said magnetic field sensing means is positioned in mounting relationship with said another one of said first and second mounting surfaces.

16. The weight sensor of claim 15 further comprising second bracket mounting guide means for positioning of said magnetic field generating means at a predetermined location relative to said longitudinal center line of said bar member.

17. The weight sensor of claim 16 wherein said second bracket mounting guide means permits transverse displacement of said magnetic field generating means in said thickness direction of said bar member.

18. The weight sensor of claim 17 wherein said first and second bracket means have identical configurations.

19. The weight sensor of claim 18 wherein said first and second bracket means each comprise a pair of identical bracket members releaseably mounted on opposite surfaces of said central web portion.

20. The weight sensor of claim 19, further comprising magnetic carrier means mounted on said one of said first and second mounting surfaces for supporting said magnetic field generating means.

21. The weight sensor of claim 20 further comprising adhesive means for securing said magnetic field generating means to said carrier means, said adhesive means being relatively viscous during a setting period such that said magnetic field generating means can be precisely displaced during said setting period in order to align the magnetic field of said magnetic field generating means with said magnetic field sensing means.

3. The weight sensor of claim 3 further comprising first bracket mounting guide means for positioning of said magnetic field sensing means in alignment with a longitudinal center line of said planar portion.

4. The weight sensor of claim 3 wherein said first bracking mounting guide means includes retaining means for preventing venting tilting of said magnetic field sensing means while permitting longitudinal displacement thereof when said magnetic field sensing means is positioned in mounting relationship with said second one of said mounting surfaces.

5. The weight sensor of claim 4 further comprising second bracket mounting guide means for positioning of said magnetic field generating means at a predetermined location relative to said longitudinal center line of said planar portion.

6. The weight sensor of claim 5 wherein said second bracket mounting guide means permits transverse displacement of said magnetic field generating means in the thickness direction of said planar portion.

7. The weight sensor of claim 6 wherein said first and second bracket means have identical configurations.

8. The weight sensor of claim 7 wherein said first and second bracket means each comprise a pair of identical bracket members releaseably mounted on opposite surfaces of said planar portion.

9. The weight sensor of claim 8 further comprising magnetic carrier means mounted on said first mounting surface for supporting said magnetic field generating means.

10. The weight sensor of claim 9 further comprising adhesive means for securing said magnetic field generating means to said carrier means, said adhesive means being relatively viscous during a setting period such that said magnetic field generating means can be precisely displaced during said setting period in order to align the magnetic field of said magnetic field generating means with said magnetic field sensing means. magnetic field fixedly secured to the other of said first and second mounting surfaces

22. A low profile multiple weight sensor system comprising:

planar support means having a thickness and a plurality of weight sensing portions;

each weight sensing portion having;

first and second section;

first and second flexible linkage means for connecting said first and second sections such that said first and second sections are substantially coplanar in an unloaded state, and are relatively displaceable with respect to each other in response to a weight load applied to said first section;

transducer means mounted on said plate means for producing an electrical output signal responsive to relative displacement of said first and second sections;

a first continuous slot connecting said first and second linkage means, said first slot defining said first and second sections and first and second mounting surfaces on said first and second sections, respectively;

said first and second mounting surfaces extending in the thickness direction of said central portion and being spaced from each other in a direction transverse to the thickness direction;

a second continuous slot isolating the weight sensing portion such that said second sections of all of said weight sensing portions are connected together to a common framework; and

said transducer means comprising means for generating a magnetic field fixedly secured to one of said first and second mounting surfaces and means for sensing the magnitude of said magnetic field fixedly secured to the other of said first and second mounting surfaces.

23. The weight sensor system of claim 22 wherein a single plate member constitutes said planar support means;

said first and second sections of said weight sensor portions are integral parts of said plate member; and

said second slot of each weight sensing portion is configured such that each of said second sections is joined to said common framework by a single, relatively narrow, tongue section.

24. A method of mounting magnetic transducer means on a low profile weight sensor;

the weight sensor comprising support means having a thickness and a slot formed therein defining first and second mounting surfaces extending in the thickness direction of the support means and being spaced from each other in a direction transverse to the thickness direction;

the transducer means comprising means for generating a magnetic field and means for sensing the magnitude of the magnetic field;

said method comprising the steps of;

fixedly mounting the magnetic field sensing means in a predetermined alignment on a first one of the first and second mounting surfaces;

adhesively mounting the magnetic field generating means on a second one of the first and second mounting surfaces using an adhesive which is relatively viscous during a setting period such that the magnetic field generating means is precisely displaceable during the setting period; and

displacing the magnetic field generating means during said setting period so as to align the magnetic field of the magnetic field generating means with the mounted magnetic field sensing means.

25. The method of claim 24 comprising the further step of:

prior to said magnetic field generating means mounting step, mounting magnetic carrier means on the support means proximate the mounting location for the magnetic field generating means.

26. The method of claim 24 wherein the magnetic carrier means is mounted on said second one of the first and second mounting surfaces so as to support the magnetic field generating means.

27. The method of claim 24 comprising the further step of:

prior to said magnetic field sensing means mounting step, mounting on the support means first bracket mounting guide means for positioning of the magnetic field sensing means in alignment with a longitudinal center line of the support means.

28. The method of claim 27 comprising the further step of:

prior to said magnetic field generating means mounting step, mounting on the support means second bracket mounting guide means for positioning of the magnetic field generating means at a predetermined location relative to the longitudinal center line of the support means.

29. The method of claim 28 wherein said first and second bracket mounting guide means mounting steps use identically configured brackets.