Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G21/00—Details of weighing apparatus
  • G01G21/24—Guides or linkages for ensuring parallel motion of the weigh-pans
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G21/00—Details of weighing apparatus
  • G01G21/23—Support or suspension of weighing platforms
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G23/00—Auxiliary devices for weighing apparatus
  • G01G23/002—Means for correcting for obliquity of mounting
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G23/00—Auxiliary devices for weighing apparatus
  • G01G23/06—Means for damping oscillations, e.g. of weigh beams
  • G01G23/12—Means for damping oscillations, e.g. of weigh beams specially adapted for preventing oscillations due to movement of the load
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L1/00—Measuring force or stress, in general
  • G01L1/26—Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload

Definitions

• the invention relates to a device for securing that the connection between a load and a load cell is ensured even under adverse operational conditions with negative loads on a load cell.
• the invention relates more specifically to installations where load cells are used for weighing on silos, mixing machinery etc. and where there is a risk of the weighed installation accidentally being tilted or falling over.
• Figure 1 show a commonly used way of securing a weighing installation against tilting
• 1 is the load cell
• 2 is a concrete surface
• 3 is a load introducing part
• 4 is a part of the structure of the weighed installation.
• the two bolts 5, which are fastened in the concrete surface 2 are passing through two holes 6 in the beam 7, which is welded to the structure member 4.
• the nuts 8 are securing that the weighed installation cannot be lifted off the load cell 1.
• the accuracy of this commonly used weighing solution is totally dependent on that the beam 7 is not in contact with the bolts 5 nor the nuts 8. These conditions are often violated in practice by the installation of the weighing system and later in use. Besides this obvious problem, this solution with the rather long bolts, is not stable with strong horizontal forces, which for example are seen during earthquakes.
• Another common solution is to secure the weighed installation by one or more bolts mounted in the upper surface of the load cell, but this solution will invariably introduce parasitic forces into the load cell, lowering the accuracy.
• the load cell 1 is clamped down on the surface 2 by the bolts 9 securing the ring or plate 10.
• the part 4 of the structure of the weighed installation is resting on the spherical upper surface 11 of the force introduction part 12 of the load cell 1.
• the locking members 13 are placed in the groove 14 of the part 4 and the groove 15 of the force introduction part 12.
• the locking members 13, which are shown as possibly being spherical balls are introduced into the grooves 14 and 15 through the opening 16 in the part 4.
• the grooves are preferably completely filled with locking members to ensure that the highest possible load can be taken up by the load cell lift-off
• the opening 16 is preferably closed by a threaded screw and additional openings 16 are preferably provided for a possible later easy removal of the locking members 13 when performing service on the load cell installation.
• the locking members 13 are preferably magnetic for even more easy removal.
• the height of the groove 14 and or possibly the groove 15 are higher than the height or diameter of the locking member 13. This allows the part 4 to tilt to a certain degree without introducing parasitic bending moments into the load cell as the load applied to the load cell is just shifting on the spherical surface 11 of the force introduction part 12.
• That the load is applied to the spherical surface 11 without any interference from the lift off protection is a prerequisite for a high accuracy of the weighing.
• the locking members 13 are shown as locking members fitting into the essentially rectangular grooves 14 and 15, which may have height which is equal to or preferably higher than the height of the locking members 13.
• Figure 5 show locking members in the form of cylindrical rollers with a height fitting into the grooves 14 and 15, and
• figure 6 show locking members with a height fitting into the grooves 14 and 15 and with an inner and outer radius fitting into respectively the grooves 15 and 14.
• Fig. 7 shows a sectional view of a load cell assembly, where a first end of the load cell 1 may be attached (not shown) to the base 2, where the load cell is provided with a second end, the force introduction part 12, configured to receive a load from a load transmission member 4.
• the load transmission member is provided with a recess 17 having a size that is larger than the outer diameter of the second end of the load cell, so that the second end 12 may be introduced into the recess of the load transmission member.
• the peripheral edge of the second end 12 may be provided with one or more grooves, that may be adapted to receive an intermediate coupling element 13, where the intermediate coupling element is locked to the side walls of the recess 17.
• the coupling element 13 may be adapted to move in a radial direction, so that prior to the placement of the load transmission member onto the load cell, the coupling elements are retracted, allowing the side walls of the recess to slip over the second end of the load cell.
• a locking sleeve 18 may be utilized to press the coupling members 13 in a radial inwards direction, allowing the coupling members to engage with the grooves, in order to prevent the load transmission member to be released from the load cell. I.e. the inner diameter of the coupling members, when engaged is smaller than the outer diameter of the grooves, so that the upper edge of the grooves will engage the coupling elements 13 if the load transmission member is pulled in a direction away from the load cell 1.
• the grooves are configured to have a vertical dimension that is larger than the vertical dimensions of the coupling element, allowing the coupling element to have a margin of movement (latitude) between the lower edge of the groove and the upper edge of the groove.
• the load transmission member 4 will be capable of tilting away from a vertical axis (central axis of the load cell) without the coupling member to come into engagement with the upper edge of the groove. I.e. that the coupling element may move in a vertical direction within the groove without engaging the groove. This ensures that the angled movement of the load transmission member will not transfer any interfering forces into the load cell, such as forces that are in a direction other than in the vertical direction. Thus, the forces that effect the movement of the load transferring member to tilt, will not affect the second end of the load cell, ensuring that parasitic forces applied to the load transmission member are isolated from the load cell.
• the attachment in the opposite direction is however secured by the coupling element, allowing some leeway of movement between the load cell and load transmission member in an upwards direction (vertical direction away from the load cell, as well as a tilting movement of the load transmission member, relative to the load cell.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Measurement Of Force In General (AREA)
• Forklifts And Lifting Vehicles (AREA)

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Citations (4)

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• 2018
  • 2018-09-07 WO PCT/DK2018/000091 patent/WO2019068292A1/en not_active Ceased
  • 2018-09-07 US US16/652,253 patent/US11408763B2/en active Active
  • 2018-09-07 EP EP18782298.6A patent/EP3692344B1/en active Active
  • 2018-09-07 CN CN201880058787.3A patent/CN111356906B/zh active Active
  • 2018-09-07 JP JP2020518687A patent/JP7233738B2/ja active Active

Patent Citations (4)

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