WO2020129055A1 - Motorized hoist with high precision load measurement arrangement - Google Patents

Motorized hoist with high precision load measurement arrangement Download PDF

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Publication number
WO2020129055A1
WO2020129055A1 PCT/IL2019/051375 IL2019051375W WO2020129055A1 WO 2020129055 A1 WO2020129055 A1 WO 2020129055A1 IL 2019051375 W IL2019051375 W IL 2019051375W WO 2020129055 A1 WO2020129055 A1 WO 2020129055A1
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WO
WIPO (PCT)
Prior art keywords
hoist
load
measurement arrangement
load measurement
motorized
Prior art date
Application number
PCT/IL2019/051375
Other languages
French (fr)
Inventor
Eitan Eilon
Original Assignee
Eilon-Engineering Industrial Weighing Systems Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eilon-Engineering Industrial Weighing Systems Ltd. filed Critical Eilon-Engineering Industrial Weighing Systems Ltd.
Publication of WO2020129055A1 publication Critical patent/WO2020129055A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
    • G01G19/14—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for weighing suspended loads
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C1/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles
    • B66C1/10—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means
    • B66C1/22—Rigid members, e.g. L-shaped members, with parts engaging the under surface of the loads; Crane hooks
    • B66C1/34—Crane hooks
    • B66C1/40—Crane hooks formed or fitted with load measuring or indicating devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66D—CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS
    • B66D1/00—Rope, cable, or chain winding mechanisms; Capstans
    • B66D1/28—Other constructional details
    • B66D1/40—Control devices
    • B66D1/48—Control devices automatic
    • B66D1/485—Control devices automatic electrical
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66D—CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS
    • B66D3/00—Portable or mobile lifting or hauling appliances
    • B66D3/18—Power-operated hoists
    • B66D3/20—Power-operated hoists with driving motor, e.g. electric motor, and drum or barrel contained in a common housing

Definitions

  • the presently disclosed subject matter generally relates to motorized hoists (hereinafter also referred to as“hoist(s)”) having a rigid hoist body configured to itself be suspended and containing a motor configured to lower and raise a load suspended to the hoist. More specifically, the presently disclosed subject matter relates to such hoist configured with a load measurement arrangement.
  • Hoists of the above-mentioned type typically have a first hook fixed to a hoist body and a second hook secured to an elongated object such as a chain, cable or rope.
  • the hoist is configured to bring the second hook to a different position relative to the hoist body upon operation of the motor.
  • the first hook can be connected to a support structure and a load to be lifted can be attached to the second hook.
  • such hoists can also be used in an opposite manner, namely with the second hook being connected to a support structure and the load being attached to the first hook. In the latter case the hoist body also is elevated together with the load.
  • a primary consideration of hoist design is to ensure components do not fail which can lead to damage, injury or even death.
  • a hoist should be as compact as possible, since, unlike other lifting devices such as cranes, such devices are often used indoors in areas having limited space (e.g., dependent on ceiling height, etc.).
  • overall length Lo the length from the hoist body to a fixed suspension element, as will be discussed below and which is called overall length Lo (see Fig. 6).
  • a length measured vertically or substantially vertically from a hoist body to an end of a fixed suspension element be as short as possible.
  • the presently disclosed subject matter may be directed towards minimizing this dimension.
  • Load measurement is known, however the presently disclosed subject matter is directed to finding a design which can provide, bearing in mind the considerations above, load measurement with high accuracy.
  • One object of the presently disclosed subject matter may be to provide an improved load element, load measurement arrangement, and hoist comprising such load measurement arrangement.
  • a motorized hoist comprising:
  • a hoist body comprising a motor
  • a first suspension element attached at a fixed distance to the hoist body and configured for attachment to a first external body
  • a second suspension element having a variable-distance attachment to the hoist body such that the motor is configured to change the position of the second suspension element relative to the hoist body, the second suspension element also being configured for attachment to a second external body;
  • a load measurement arrangement configured to determine the weight of a load suspended by the hoist
  • the load measurement arrangement comprising:
  • one or more sensors configured to measure a load applied to the load element and transmit information regarding the load measured
  • first suspension element is attached at a fixed distance with the load element being located between the hoist body and the first suspension element such that all compressive forces between the hoist body and the first suspension element are applied to the load element.
  • a load element like all physical objects, will be compressed when subject to compressive forces, yet the term“fixed” used in relation to the first suspension element is to be contrasted with the second suspension element being configured to be moved in its entirety relative to the hoist body.
  • the load element of the type under discussion has negligible compression or, stated differently, compression not visible to the eye.
  • suspension elements are hooks that may or may not be configured for rotational movement (i.e., swiveling), although it will be appreciated that other devices may be provided to connect the hoist to an external body.
  • the load measurement arrangement may further comprise a suspension bridge, the first suspension element being a hook comprising a hook portion and shaft portion and the fixed-distance attachment including the load element being mounted to the shaft portion with the suspension bridge being closer to the hook portion than the load element.
  • the load measurement arrangement may further comprise a tilt sensor configured to measure deviation of the load element from a vertical orientation.
  • the tilt sensor may comprise an accelerometer.
  • the load measurement arrangement may be configured to allow forces to be applied to the load element in a only single direction.
  • the load measurement arrangement may be configured to extend substantially perpendicular to a longest dimension of the hoist body.
  • the load measurement arrangement may be configured to receive power from a primary power source.
  • the primary power source may receive power from the hoist body.
  • the load measurement arrangement may further comprise a battery unit constituting a backup power source.
  • the load measurement arrangement may further comprise a control unit.
  • the control unit may comprise an electronic circuit.
  • the control unit may be connected to the one or more sensors via one or more wires.
  • the control unit may be configured to receive measurement information from the one or more sensors.
  • the control unit may be configured to transmit measurement information to a remote location.
  • the transmission of measurement information may be through a wired connection or a wireless transmitter.
  • the control unit may be configured to halt operation of the motor when an undesired load is detected.
  • the control unit may comprise the tilt sensor.
  • the control unit may be configured to halt or modify an operative state of the motor and/or the hoist body.
  • the first suspension element may be rotatable.
  • the first suspension element may be a hook comprising a hook portion and a shaft.
  • the load element may be configured to extend perpendicularly to the shaft portion of a hook, the hook being adjacent to the load element.
  • the load measurement arrangement may be configured to facilitate remote monitoring of the determined weight.
  • the load measurement arrangement may be configured to facilitate automated monitoring of the determined weight.
  • the one or more sensors may comprise one or more strain gauges.
  • the load measurement arrangement may be configured to transmit information regarding the load measured to a remote location.
  • the load measurement arrangement may be configured to provide measurement information only at a location distant from the load element.
  • the load measurement arrangement may further comprise a lug nut and corresponding pin configured to secure the load element to a suspension bridge.
  • a hoist load measurement arrangement comprising:
  • one or more sensors configured to measure a load applied to the load element and transmit the load measured
  • load element is located relative to the suspension bridge and the first suspension element such that all compressive forces applied by the first suspension element to the suspension bridge are applied to the load element.
  • the load element may comprise a ring-shape.
  • the hoist load measurement arrangement may comprise a plurality of the sensors circumferentially spaced apart on the ring-shape.
  • the sensors may be spaced equally apart.
  • the load element may comprise at least one projection or recess configured to prevent rotation of the load element relative to the other components of the hoist load measurement arrangement.
  • the at least one projection or recess may be at least one projection, and be configured to prevent rotation of the load element relative to the other components of the hoist load measurement arrangement, the projection being an outwardly projecting projection.
  • the outwardly projecting projection may extend outwardly in a radial direction.
  • the hoist load measurement arrangement may comprise at least four of the sensors.
  • the hoist load measurement arrangement may comprise at least six of the sensors.
  • the one or more sensors may be located within the load element.
  • the hoist load measurement arrangement may be configured to receive power from a primary power source.
  • the hoist load measurement arrangement may further comprise a battery unit constituting a backup power source.
  • the hoist load measurement arrangement may further comprise a tilt sensor configured to measure deviation of the load element from a vertical orientation.
  • the tilt sensor may comprise an accelerometer.
  • the hoist load measurement arrangement may be configured to allow forces to be applied to the load element in a only single direction.
  • the hoist load measurement arrangement may further comprise a control unit.
  • the control unit may comprise an electronic circuit.
  • the control unit may be connected to the one or more sensors via one or more wires.
  • the control unit may be configured to receive measurement information from the one or more sensors.
  • the control unit may be configured to transmit measurement information to a remote location.
  • the transmission of measurement information may be through a wired connection or a wireless transmitter.
  • the control unit may comprise the tilt sensor.
  • the first suspension element may be rotatable.
  • the first suspension element may be a hook comprising a hook portion and a shaft.
  • the load element may be configured to extend perpendicularly to the shaft portion of the hook, the hook being adjacent to the load element.
  • the hoist load measurement arrangement may be configured to facilitate remote monitoring of the determined weight.
  • the hoist load measurement arrangement may be configured to facilitate automated monitoring of the determined weight.
  • the one or more sensors may comprise one or more strain gauges.
  • the hoist load measurement arrangement may be configured to transmit information regarding the load measured to a remote location.
  • the hoist load measurement arrangement may be configured to provide measurement information only at a location distant from the load element.
  • the hoist load measurement arrangement may further comprise a lug nut and corresponding pin configured to secure the load element to a suspension bridge.
  • a motorized hoist comprising a load element located between a hoist body and a first suspension element attached at a fixed distance to the hoist body, such that all compressive forces between the hoist body and the first suspension element are applied to the load element.
  • locating the load element between two components fixed to each other may reduce the likelihood of damage (as compared, e.g., to having the load element attached to the variable-distance second suspension element, which can, for example, swing or hit objects when being lifted or lowered).
  • a load element connecting a hoist body via a fixed attachment to a suspension element provides controlled application of all compressive forces through the load element and has produced a solution with the most compact and least number of components of different systems conceived.
  • a motorized hoist comprising:
  • a hoist body comprising a motor
  • a first suspension element attached at a fixed distance to the hoist body and configured for attachment to a first external body
  • a second suspension element having a variable-distance attachment to the hoist body such that the motor is configured to change the position of the second suspension element relative to the hoist body, the second suspension element also being configured for attachment to a second external body;
  • a load measurement arrangement configured to determine the weight of a load suspended by the hoist
  • the load measurement arrangement comprising: a load element
  • one or more sensors configured to measure a load applied to the load element and transmit the load measured
  • the first suspension element is a hook comprising a hook portion and shaft portion and the fixed distance attachment includes the load element being mounted to the shaft portion with the suspension bridge being closer to the hook portion than the load element.
  • a motorized hoist comprising a load element which is mounted to a shaft portion of a first suspension element with a suspension bridge being closer to a hook portion of the first suspension element than the load element, the first suspension element being attached at a fixed distance to a hoist body.
  • a motorized hoist comprising:
  • a hoist body comprising a motor
  • a first suspension element attached at a fixed distance to the hoist body and configured for attachment to a first external body
  • a second suspension element having a variable-distance attachment to the hoist body such that the motor is configured to change the position of the second suspension element relative to the hoist body, the second suspension element also being configured for attachment to a second external body;
  • a load measurement arrangement configured to determine the weight of a load suspended by the hoist
  • the load measurement arrangement comprising: a load element
  • one or more sensors configured to measure a load applied to the load element and transmit the load measured
  • a tilt sensor configured to measure deviation of the load element from a vertical orientation.
  • a motorized hoist comprising a load measurement arrangement comprising a load element, one or more sensors configured to measure a load applied to the load element and transmit the load measured and a tilt sensor configured to measure a deviation of the load element from a vertical orientation.
  • Yet another advantage is that the presently disclosed subject matter may allow easy monitoring of the load from an external location, or even automated monitoring, allowing a reduction in manpower.
  • a hoist load measurement arrangement comprising:
  • one or more sensors configured to measure a load applied to the load element and transmit the load measured
  • load element is located relative to the suspension bridge and the first suspension element such that all compressive forces applied by the first suspension element to the suspension bridge are applied to the load element.
  • a hoist load measurement arrangement comprising:
  • one or more sensors configured to measure a load applied to the load element and transmit the load measured
  • a first suspension element in the form of a hook comprising a shaft portion and a hook portion
  • a hoist load measurement arrangement comprising:
  • one or more sensors configured to measure a load applied to the load element and transmit the load measured
  • a tilt sensor configured to measure deviation of the load element from a vertical orientation.
  • a hoist load element comprising: a ring-shape; and at least one projection or recess configured to prevent rotation of the load element.
  • a motorized hoist comprising: a hoist body comprising a tilt sensor.
  • the load element or load measurement arrangement can have one or more of the following features:
  • the load element may have a ring-shape, i.e., the load element can have a through hole extending through the middle thereof.
  • the load element may comprise at least one an anti-rotation element.
  • the anti-rotation element can be a projection or recess configured to prevent rotation of the load element.
  • the anti-rotation element is at least one outwardly projecting projection.
  • the anti-rotation element may be a single outwardly projecting projection. The single projection may extend outwardly in a radial direction.
  • the one or more sensors may be strain gauges.
  • the load element is ring-shaped and the one or more sensors is a plurality of sensors circumferentially spaced-apart on the ring-shape.
  • the plurality of sensors may be are equally circumferentially spaced-apart on the ring-shape.
  • the plurality of sensors may include more than four sensors, for example six or more sensors.
  • the tilt sensor may be an accelerometer.
  • a load measurement arrangement may be configured to receive power from a primary power source and can further comprise a battery unit as a backup power source.
  • the load measurement arrangement can be impervious to electricity failures. While such electricity stoppage would also stop any movement of the hoist, the presently disclosed subject matter considers any overload information to be still of use to the operator, even in such circumstance. It will be understood that sometimes a user may choose to shut down the electricity yet still desire to know a load measurement of a load being suspended.
  • a motorized hoist can comprise a hoist body, first and second suspension elements and a load measurement arrangement.
  • a hoist body can comprise a motor.
  • First and second suspension elements can be configured for attachment to external bodies.
  • First and second suspension elements may be hooks the hooks can comprise a hook portion and a shaft portion.
  • a first suspension element can be attached at a fixed distance to a hoist body.
  • the first suspension element can be secured in a rigid manner to the hoist body. Nonetheless, even though the first suspension element can be a fixed distance or fixed in a rigid manner, it can be configured for rotational movement.
  • a second suspension element can have a variable-distance attachment to a hoist body.
  • a motor of the hoist body can be configured to change the position of the second suspension element relative to the hoist body.
  • the second suspension element can be a hook attached to the hoist body via a chain and the motor can change the extension of the chain from the hoist body.
  • a load measurement arrangement can be configured to determine the weight of a load suspended by a hoist.
  • a load measurement arrangement can comprise a load element and one or more sensors configured to measure a load applied to the load element.
  • the one or more sensors may be more than four sensors.
  • a load measurement arrangement can comprise a load element and one or more sensors, and a tilt sensor.
  • the one or more sensors can be located within the load element.
  • a load measurement arrangement can be configured to transmit measurement information to a distant location.
  • the load measurement arrangement is configured to only provide measurement information at a location distant to a load element.
  • a load measurement arrangement can be configured to hold a load element in a static position (i.e., unable to translate or rotate).
  • the load measurement arrangement may be configured to only allow forces to be applied to the load element in a single direction, for example only allowing the load element to be subject to compressive forces.
  • a load measurement arrangement can comprise at least one power source.
  • the measurement arrangement may comprise a battery unit as a backup power source.
  • the load measurement arrangement comprises two power sources, a first power source receiving power from the hoist body and a second power source constituted by a battery unit as a backup power source. It is also feasible that a load measurement arrangement could comprise only a single power source (either from the hoist body or a battery unit).
  • a load measurement unit can comprise a control unit.
  • the control unit can comprise an electronic circuit.
  • the control unit can be configured to receive power from one or more power sources.
  • the control unit can be configured to receive measurement information from the one or more sensors.
  • the control unit can be configured to transmit measurement information to a distant location. This may be through a wired connection or a wireless transmitter.
  • the control unit can be located external to the housing.
  • the control unit may be located within a hoist body.
  • the control unit can be connected via a wire to the one or more sensors which are located inside the load element.
  • the control unit can be configured to halt or modify a motor or a hoist body’s operative state. For example, the control unit can be configured to halt operation of a motor in the case of a detected undesired load.
  • a tilt sensor may be located within a control unit.
  • a load measurement arrangement can comprise an anti-rotation element configured to prevent rotation of a load element.
  • the anti-rotation element can be one or more outwardly projecting projections and a suspension bridge can have one or more recesses configured for receiving the one or more projecting portions.
  • a load measurement arrangement can comprise a lug nut and corresponding pin configured to secure a load element to a suspension bridge.
  • the pin can extend through a pin hole formed in the second end of the load element to prevent the lug nut from loosening.
  • a load element can be located between a hoist body and a fixed distance first suspension element such that all compressive forces between the hoist body and the first suspension element are applied to the load element.
  • a suspension bridge can be located between a load element and a hook portion of a first suspension element.
  • the orientation of the load element or load measurement arrangement can be such that it minimizes any bending or non-axial forces.
  • the load element can be configured to extend perpendicular or substantially perpendicular to a longest dimension of the hoist body.
  • the load element can be configured to extend perpendicular with a shaft portion of a hook which is adjacent to the load element.
  • One or more sensors can be configured to measure a load applied to the load element and transmit the load measured.
  • the one or more sensors may be configured to measure strain.
  • Fig. 1 is a schematic perspective view of a hoist in accordance with the presently disclosed subject matter
  • Fig. 2 is a schematic perspective view of a first suspension element and load measuring arrangement of the hoist in Fig. 1 ;
  • Fig. 3 is an exploded view of the first suspension element and load measuring arrangement in Fig. 2, except for the electronic components thereof;
  • Fig. 4A is an upper perspective view of a suspension bridge of the load measuring arrangement in Fig. 2;
  • Fig. 4B is a lower perspective view of the suspension bridge in Fig. 4A
  • Fig. 4C is a side view of the suspension bridge in Fig. 4A;
  • Fig. 4D is a bottom view of the suspension bridge in Fig. 4A;
  • Fig. 5A is a perspective view of a load element of the load measuring arrangement in Fig. 2;
  • Fig. 5B is a side view of the load element in Fig. 5A;
  • Fig. 5C is a top view of the load element in Figs. 5A and 5B, further schematically showing a plurality of sensors and attached wires;
  • Fig. 6 is a partial section view of the first suspension element and load measuring arrangement in Fig. 2, excluding the electronic components thereof;
  • Fig. 7 is an exploded view of the first suspension element and a modification of the load measuring arrangement in Fig. 2.
  • Fig. 1 illustrates an example hoist 10.
  • the hoist 10 comprises a hoist body 12, a first suspension element 14 secured to the hoist body 12, a motor 16 (schematically shown in dashed lines), a chain 18 engaging the motor 16, and a second suspension element 20 attached to the chain 18.
  • the first and second suspension elements 14, 20 may be hooks. Referring also to Fig. 3, (using the first suspension element 14 as an example, noting that both are identical) the first suspension element 14 comprises a hook portion 24, an integrally formed shaft portion 26, and a latch portion 28.
  • the first suspension element 14 may be attached to a suspension bridge 30 in a manner that it can only rotate relative to the suspension bridge 30.
  • the suspension bridge 30 is firmly secured to the hoist body 12 such that it cannot move relative thereto. Accordingly, the first suspension element 14 is attached to the hoist body 12 at a constant or fixed distance thereto, the distance being substantially adjacent thereto.
  • the second suspension element 20 can be brought to different distances from the hoist body 12 upon operation of the motor 16.
  • the hoist 10 comprises a load measurement arrangement 32 (which comprises all elements shown in Fig. 2 except for the first suspension element 14).
  • the load measurement arrangement 32 comprises in a broadest sense a load element 34 and one or more sensors 36 (which in this example are six equally circumferentially spaced strain gauges 36A, 36B, 36C, 36D, 36E, 36F).
  • the load measurement arrangement 32 can further comprises electronic components.
  • each of the sensors can be connected with one or more wires 37.
  • the load measurement arrangement 32 can comprise a control unit 38 (for example located in the hoist body 12 as shown in Fig. 1) comprising an electronic circuit 40 (Fig. 2), wiring 42 connecting the one or more sensors 36 to the control unit 38 for transfer of measurement information, further wiring 44 for transmitting information from the circuit 40 to an external location (not shown), wiring 46 for receiving power from a primary power source (not shown) and extending to the control unit 38, a back-up battery power source 48, and wiring 50 connecting it to the control unit 38.
  • a control unit 38 for example located in the hoist body 12 as shown in Fig. 1
  • the load measurement arrangement 32 can comprise a control unit 38 (for example located in the hoist body 12 as shown in Fig. 1) comprising an electronic circuit 40 (Fig. 2), wiring 42 connecting the one or more sensors 36 to the control unit 38 for transfer of measurement information, further wiring 44 for transmitting information from the circuit 40 to an external location
  • the load measurement arrangement 32 can further comprise a securing arrangement (all elements designated as “52”) for securing the load element 34 to the first suspension element 14 and suspension bridge 30.
  • suspension bridge 30 is configured to hold the load element in place, it is also considered part of the load measurement arrangement 32 and not the securing arrangement 52.
  • the securing arrangement 52 comprises a lug nut 54, and a pin 56 mounted in a slot 58 of the lug nut 54 for halting rotational movement relative to the load element 34.
  • the suspension bridge 30 comprises a cover wall 60 and a peripheral wall 62 extending adjacent the perimeter of the cover wall 60.
  • the cover wall 60 has an outer surface 64 facing towards the first suspension element 14 (e.g., Fig. 6).
  • First and second bores 66, 68 extend through the cover wall 60 at opposite ends of the suspension bridge 30 and are configured to receive screws (not shown) therethrough to secure the suspension bridge 30 to corresponding threaded bores (not shown) of the hoist body 12. Between the first and second bores 66, 68 there is a securing section 70, a chamber section 72, and a side wall 74 separating them.
  • the securing section 70 is configured to secure the first suspension element 14 to the suspension bridge 30 and thus has a suspension aperture 76 formed in the cover wall 60 which is configured for receiving the shaft portion 26 therethrough.
  • a notch 78 is formed in the side wall 74. This is used to prevent rotation of the load element 34 as described hereinafter.
  • the notch 78 provides a further function of allowing the wiring 42 (Fig. 2) from the load element 34 to extend therethrough and into the hoist body 12.
  • the load element 34 34 can comprise parallel top and bottom surfaces 80, 82 and an external peripheral surface 84 extending therebetween.
  • the load element 34 may be ring-shaped about a central axis Ac. Accordingly, the external peripheral surface 84, and a corresponding internal peripheral surface 85, are both cylindrical.
  • the sensors 36 may be equally circumferentially spaced apart; for example, in the example described herein with reference to an illustrated in the accompanying figures, each of the six sensors are spaced from adjacent sensors by an angle of 60°about the central axis Ac.
  • the load element 34 further comprises an anti-rotation element 86, which may be a single outwardly radially projecting projection. As shown in Fig. 2, the anti-rotation element 86 is sized to fit in the notch 78.
  • the inner peripheral surface 85 forms a through-hole 88 sized to receive the shaft portion 26.
  • the external peripheral surface 84 is formed with an aperture 89 via which the wire 42 can exit the load element 34.
  • the lug nut 54 further comprises an external connection arrangement 55 (such as hexagonally arranged surfaces) and an internal threading 57.
  • the first suspension element 14 comprises the shaft portion 26 which in turn comprises an external threading 90 and a pin hole portion 92 for receiving the pin 56.
  • the load element 34 is inserted in the suspension bridge 30 such that the anti- rotation element 86 is located in the notch 78 to prevent rotation of the load element 34 relative to the suspension bridge 30.
  • the shaft portion 26 is then inserted through the suspension aperture 76 of the suspension bridge 30, and then the load element’s through-hole 88, and finally the external threading 90 of the shaft portion 26 is threaded to the corresponding internal threading 57 of the lug nut 54 thereby securing the first suspension element 14 to the suspension bridge 30.
  • the pin 56 is then inserted in the pin hole portion 92 to prevent further relative rotation of the lug nut 54 and shaft portion 26.
  • the first suspension element 14 is now held to the suspension bridge 30 yet can rotate relative thereto. It will be understood that the rotation capability is an option, and modification in which such rotation is constrained may be provided without departing from the scope of the presently disclosed subject matter, mutatis mutandis.
  • the first suspension element 14 is suspended from a support structure (not shown) and the second suspension element suspends a load (not shown). It will be understood that these functions could be reversed.
  • the controller 20 is used to change the height of the load by, for example, shortening the second suspension element’s 20 distance to the hoist body 12.
  • the sensor 36 measures the strain on the load element 34 and transmits the information to the control unit 38 which processes it and, for example, transmits it to an appropriate display unit (not shown) for an operator.
  • a tilt sensor schematically shown in Fig. 2 and designated“94” may be provided.
  • a tilt sensor 94 configured to measure a deviation of the load element 34 (or hoist body 12) from a vertical orientation allows the circuit 40 to correct an error of measurement caused by the tilting of the hoist body 12, which may improve the accuracy of the load measurement.
  • a first suspension element 114 is provided comprising a hook portion 124, an integrally formed shaft portion 126, and a latch portion 128.
  • the first suspension element 114 may be attached to a housing 130 in a manner that it can only rotate relative thereto.
  • the housing 130 may be firmly secured to a hoist body (not illustrated) such that it cannot move relative thereto. Accordingly, the first suspension element 114 is attached to the hoist body at a constant or fixed distance thereto, the distance being substantially adjacent thereto.
  • a load measuring arrangement 132 comprising a load element 134 and a securing arrangement 152.
  • the load element 134 may be provided as described above with reference to and illustrated in the accompanying drawings, for example comprising one or more sensors and suitable electronic components (not illustrated).
  • the securing arrangement 152 may comprise a lug nut 154 and a pin 156, mounted in a slot 158 formed in the lug nut for preventing rotational movement relative to the load element 134, for example as described above with reference to and illustrated in the accompanying drawings.
  • the load measuring arrangement 132 may further comprise one or more bearings.
  • one or more disc bearing 200 may be provided about the shaft portion 126 of the first suspension element 114, facilitating smooth rotation thereof about a central axis.
  • the disc bearing 200 may comprise a single piece of smooth material such as a urethane, or may comprise a ball bearing, roller bearing, or any other suitable arrangement.
  • the load measuring arrangement 132 may further comprise a spherical bearing 202, for example between the disc bearings 200 and the load element 134.
  • the spherical beating 202 provides rotational freedom, which may facilitate an increased accuracy in the load measurement by the load element 134.

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Abstract

A motorized hoist is provided, comprising a hoist body with a motor, a first suspension element attached at a fixed distance to the hoist body and configured for attachment to a first external body, a second suspension element for attachment to a second external body and having a variable-distance attachment to the hoist body such that the motor is configured to change the position of the second suspension element relative to the hoist body, and a load measurement arrangement configured to determine the weight of a load. The load measurement arrangement comprises a load element and one or more sensors to measure a load applied. The first suspension element is attached at a fixed distance with the load element being located between the hoist body and the first suspension element such that all compressive forces between the hoist body and the first suspension element are applied thereto.

Description

MOTORIZED HOIST WITH HIGH PRECISION LOAD MEASUREMENT
ARRANGEMENT
TECHNOLOGICAL FIELD
The presently disclosed subject matter generally relates to motorized hoists (hereinafter also referred to as“hoist(s)”) having a rigid hoist body configured to itself be suspended and containing a motor configured to lower and raise a load suspended to the hoist. More specifically, the presently disclosed subject matter relates to such hoist configured with a load measurement arrangement.
BACKGROUND
Hoists of the above-mentioned type typically have a first hook fixed to a hoist body and a second hook secured to an elongated object such as a chain, cable or rope. The hoist is configured to bring the second hook to a different position relative to the hoist body upon operation of the motor. During operation the first hook can be connected to a support structure and a load to be lifted can be attached to the second hook. Alternatively, such hoists can also be used in an opposite manner, namely with the second hook being connected to a support structure and the load being attached to the first hook. In the latter case the hoist body also is elevated together with the load.
A primary consideration of hoist design is to ensure components do not fail which can lead to damage, injury or even death.
Accordingly, it is highly beneficial for a user to know what load or weight is being suspended by the hoist, and with as much accuracy as required.
Not only is it beneficial but increasing legal requirements such as directives introduced in 2018 by the European Parliament require load monitoring and immediate correction of overloads or underloads.
Accordingly, it is desired for such load measuring systems to be as accurate as possible to avoid overloading or failure.
A further consideration, of specific importance to the types of hoists subject the present application, is that a hoist should be as compact as possible, since, unlike other lifting devices such as cranes, such devices are often used indoors in areas having limited space (e.g., dependent on ceiling height, etc.). By compact, it is noted that the specific dimension under discussion is the length from the hoist body to a fixed suspension element, as will be discussed below and which is called overall length Lo (see Fig. 6). Stated differently, it is desirable that a length measured vertically or substantially vertically from a hoist body to an end of a fixed suspension element be as short as possible. It will be understood that the presently disclosed subject matter may be directed towards minimizing this dimension. However, it is within the scope of the presently disclosed subject matter to provide a system or hoist which is not restricted to having as short an overall length as possible (e.g., an outdoor hoist).
Load measurement is known, however the presently disclosed subject matter is directed to finding a design which can provide, bearing in mind the considerations above, load measurement with high accuracy.
While the discussion above has been focused on the primary considerations of a load measurement arrangement that does not fail and provides high load measurement accuracy, other desired qualities such as fatigue-rating, compactness, and high repeatability are of importance.
One object of the presently disclosed subject matter may be to provide an improved load element, load measurement arrangement, and hoist comprising such load measurement arrangement.
SUMMARY
According to an aspect of the presently disclosed subject matter, there is provided a motorized hoist comprising:
a hoist body comprising a motor;
a first suspension element attached at a fixed distance to the hoist body and configured for attachment to a first external body;
a second suspension element having a variable-distance attachment to the hoist body such that the motor is configured to change the position of the second suspension element relative to the hoist body, the second suspension element also being configured for attachment to a second external body; and
a load measurement arrangement configured to determine the weight of a load suspended by the hoist;
the load measurement arrangement comprising:
a load element; and
one or more sensors configured to measure a load applied to the load element and transmit information regarding the load measured;
wherein the first suspension element is attached at a fixed distance with the load element being located between the hoist body and the first suspension element such that all compressive forces between the hoist body and the first suspension element are applied to the load element. It will also be understood that a load element, like all physical objects, will be compressed when subject to compressive forces, yet the term“fixed” used in relation to the first suspension element is to be contrasted with the second suspension element being configured to be moved in its entirety relative to the hoist body. Further it is noted that the load element of the type under discussion has negligible compression or, stated differently, compression not visible to the eye.
Typically the suspension elements are hooks that may or may not be configured for rotational movement (i.e., swiveling), although it will be appreciated that other devices may be provided to connect the hoist to an external body.
The load measurement arrangement may further comprise a suspension bridge, the first suspension element being a hook comprising a hook portion and shaft portion and the fixed-distance attachment including the load element being mounted to the shaft portion with the suspension bridge being closer to the hook portion than the load element.
The load measurement arrangement may further comprise a tilt sensor configured to measure deviation of the load element from a vertical orientation. The tilt sensor may comprise an accelerometer.
The load measurement arrangement may be configured to allow forces to be applied to the load element in a only single direction.
The load measurement arrangement may be configured to extend substantially perpendicular to a longest dimension of the hoist body.
The load measurement arrangement may be configured to receive power from a primary power source. The primary power source may receive power from the hoist body. The load measurement arrangement may further comprise a battery unit constituting a backup power source.
The load measurement arrangement may further comprise a control unit.
The control unit may comprise an electronic circuit.
The control unit may be connected to the one or more sensors via one or more wires.
The control unit may be configured to receive measurement information from the one or more sensors.
The control unit may be configured to transmit measurement information to a remote location.
The transmission of measurement information may be through a wired connection or a wireless transmitter.
The control unit may be configured to halt operation of the motor when an undesired load is detected. The control unit may comprise the tilt sensor.
The control unit may be configured to halt or modify an operative state of the motor and/or the hoist body.
The first suspension element may be rotatable.
The first suspension element may be a hook comprising a hook portion and a shaft.
The load element may be configured to extend perpendicularly to the shaft portion of a hook, the hook being adjacent to the load element.
The load measurement arrangement may be configured to facilitate remote monitoring of the determined weight.
The load measurement arrangement may be configured to facilitate automated monitoring of the determined weight.
The one or more sensors may comprise one or more strain gauges.
The load measurement arrangement may be configured to transmit information regarding the load measured to a remote location.
The load measurement arrangement may be configured to provide measurement information only at a location distant from the load element.
The load measurement arrangement may further comprise a lug nut and corresponding pin configured to secure the load element to a suspension bridge.
According to another aspect of the presently disclosed subject matter, there is provided a hoist load measurement arrangement comprising:
a load element;
one or more sensors configured to measure a load applied to the load element and transmit the load measured;
a first suspension element; and
a suspension bridge;
wherein the load element is located relative to the suspension bridge and the first suspension element such that all compressive forces applied by the first suspension element to the suspension bridge are applied to the load element.
The load element may comprise a ring-shape.
The hoist load measurement arrangement may comprise a plurality of the sensors circumferentially spaced apart on the ring-shape.
The sensors may be spaced equally apart. The load element may comprise at least one projection or recess configured to prevent rotation of the load element relative to the other components of the hoist load measurement arrangement. The at least one projection or recess may be at least one projection, and be configured to prevent rotation of the load element relative to the other components of the hoist load measurement arrangement, the projection being an outwardly projecting projection. The outwardly projecting projection may extend outwardly in a radial direction.
The hoist load measurement arrangement may comprise at least four of the sensors. The hoist load measurement arrangement may comprise at least six of the sensors.
The one or more sensors may be located within the load element.
The hoist load measurement arrangement may be configured to receive power from a primary power source.
The hoist load measurement arrangement may further comprise a battery unit constituting a backup power source.
The hoist load measurement arrangement may further comprise a tilt sensor configured to measure deviation of the load element from a vertical orientation. The tilt sensor may comprise an accelerometer.
The hoist load measurement arrangement may be configured to allow forces to be applied to the load element in a only single direction.
The hoist load measurement arrangement may further comprise a control unit. The control unit may comprise an electronic circuit.
The control unit may be connected to the one or more sensors via one or more wires.
The control unit may be configured to receive measurement information from the one or more sensors.
The control unit may be configured to transmit measurement information to a remote location. The transmission of measurement information may be through a wired connection or a wireless transmitter.
The control unit may comprise the tilt sensor.
The first suspension element may be rotatable.
The first suspension element may be a hook comprising a hook portion and a shaft.
The load element may be configured to extend perpendicularly to the shaft portion of the hook, the hook being adjacent to the load element.
The hoist load measurement arrangement may be configured to facilitate remote monitoring of the determined weight. The hoist load measurement arrangement may be configured to facilitate automated monitoring of the determined weight.
The one or more sensors may comprise one or more strain gauges.
The hoist load measurement arrangement may be configured to transmit information regarding the load measured to a remote location. The hoist load measurement arrangement may be configured to provide measurement information only at a location distant from the load element.
The hoist load measurement arrangement may further comprise a lug nut and corresponding pin configured to secure the load element to a suspension bridge.
According to another aspect of the presently disclosed subject matter, there is provided a motorized hoist comprising a load element located between a hoist body and a first suspension element attached at a fixed distance to the hoist body, such that all compressive forces between the hoist body and the first suspension element are applied to the load element.
It will be understood that the location of the load element may be considered advantageous.
For example, locating the load element between two components fixed to each other may reduce the likelihood of damage (as compared, e.g., to having the load element attached to the variable-distance second suspension element, which can, for example, swing or hit objects when being lifted or lowered).
As will be described in further detail below, it has been found that a load element connecting a hoist body via a fixed attachment to a suspension element provides controlled application of all compressive forces through the load element and has produced a solution with the most compact and least number of components of different systems conceived.
While it may be theoretically possible to redesign existing hoist bodies to accommodate such compressive load element within or substantially within the hoist body the present aspect takes into account that the presently disclosed subject matter may be retrofitted to existing systems, which greatly reduces the complexity of redesigning known hoists and is therefore significantly advantageous.
According to another aspect of the presently disclosed subject matter, there is provided a motorized hoist comprising:
a hoist body comprising a motor;
a first suspension element attached at a fixed distance to the hoist body and configured for attachment to a first external body;
a second suspension element having a variable-distance attachment to the hoist body such that the motor is configured to change the position of the second suspension element relative to the hoist body, the second suspension element also being configured for attachment to a second external body; and
a load measurement arrangement configured to determine the weight of a load suspended by the hoist;
the load measurement arrangement comprising: a load element;
one or more sensors configured to measure a load applied to the load element and transmit the load measured; and
a suspension bridge;
wherein the first suspension element is a hook comprising a hook portion and shaft portion and the fixed distance attachment includes the load element being mounted to the shaft portion with the suspension bridge being closer to the hook portion than the load element.
According to another aspect of the presently disclosed subject matter, there is provided a motorized hoist comprising a load element which is mounted to a shaft portion of a first suspension element with a suspension bridge being closer to a hook portion of the first suspension element than the load element, the first suspension element being attached at a fixed distance to a hoist body.
According to another aspect of the presently disclosed subject matter, there is provided a motorized hoist comprising:
a hoist body comprising a motor;
a first suspension element attached at a fixed distance to the hoist body and configured for attachment to a first external body;
a second suspension element having a variable-distance attachment to the hoist body such that the motor is configured to change the position of the second suspension element relative to the hoist body, the second suspension element also being configured for attachment to a second external body; and
a load measurement arrangement configured to determine the weight of a load suspended by the hoist;
the load measurement arrangement comprising: a load element;
one or more sensors configured to measure a load applied to the load element and transmit the load measured;
a tilt sensor configured to measure deviation of the load element from a vertical orientation.
According to another aspect of the presently disclosed subject matter, there is provided a motorized hoist comprising a load measurement arrangement comprising a load element, one or more sensors configured to measure a load applied to the load element and transmit the load measured and a tilt sensor configured to measure a deviation of the load element from a vertical orientation.
It will be understood that in order to achieve the highest possible load measurement accuracy, all compressive forces of the hoist must be applied to the load element.
Yet another advantage is that the presently disclosed subject matter may allow easy monitoring of the load from an external location, or even automated monitoring, allowing a reduction in manpower.
According to another aspect of the presently disclosed subject matter, there is provided a hoist load measurement arrangement comprising:
a load element;
one or more sensors configured to measure a load applied to the load element and transmit the load measured;
a first suspension element; and a suspension bridge;
wherein the load element is located relative to the suspension bridge and the first suspension element such that all compressive forces applied by the first suspension element to the suspension bridge are applied to the load element.
According to another aspect of the presently disclosed subject matter, there is provided a hoist load measurement arrangement comprising:
a load element;
one or more sensors configured to measure a load applied to the load element and transmit the load measured;
a first suspension element in the form of a hook comprising a shaft portion and a hook portion; and
a suspension bridge;
wherein the load element mounted to the shaft portion with the suspension bridge being closer to the hook portion than the load element.
According to another aspect of the presently disclosed subject matter, there is provided a hoist load measurement arrangement comprising:
a load element;
one or more sensors configured to measure a load applied to the load element and transmit the load measured;
a tilt sensor configured to measure deviation of the load element from a vertical orientation. According to another aspect of the presently disclosed subject matter, there is provided a hoist load element comprising: a ring-shape; and at least one projection or recess configured to prevent rotation of the load element.
According to another aspect of the presently disclosed subject matter, there is provided a motorized hoist comprising: a hoist body comprising a tilt sensor.
According to any of the aspects above, the load element or load measurement arrangement can have one or more of the following features:
• The load element may have a ring-shape, i.e., the load element can have a through hole extending through the middle thereof.
• The load element may comprise at least one an anti-rotation element. The anti-rotation element can be a projection or recess configured to prevent rotation of the load element. According to one example, the anti-rotation element is at least one outwardly projecting projection. The anti-rotation element may be a single outwardly projecting projection. The single projection may extend outwardly in a radial direction.
• The one or more sensors may be strain gauges.
• The load element is ring-shaped and the one or more sensors is a plurality of sensors circumferentially spaced-apart on the ring-shape. The plurality of sensors may be are equally circumferentially spaced-apart on the ring-shape. The plurality of sensors may include more than four sensors, for example six or more sensors.
• The tilt sensor may be an accelerometer.
• A load measurement arrangement may be configured to receive power from a primary power source and can further comprise a battery unit as a backup power source.
With such feature the load measurement arrangement can be impervious to electricity failures. While such electricity stoppage would also stop any movement of the hoist, the presently disclosed subject matter considers any overload information to be still of use to the operator, even in such circumstance. It will be understood that sometimes a user may choose to shut down the electricity yet still desire to know a load measurement of a load being suspended.
It will be understood that the above-said is a summary, and that any of the aspects above may further comprise any of the features described hereinbelow. Specifically, the following features, either alone or in combination, may be applicable to any of the above aspects:
A. A motorized hoist can comprise a hoist body, first and second suspension elements and a load measurement arrangement. B. A hoist body can comprise a motor.
C. First and second suspension elements can be configured for attachment to external bodies.
First and second suspension elements may be hooks the hooks can comprise a hook portion and a shaft portion.
D. A first suspension element can be attached at a fixed distance to a hoist body. Stated
differently, the first suspension element can be secured in a rigid manner to the hoist body. Nonetheless, even though the first suspension element can be a fixed distance or fixed in a rigid manner, it can be configured for rotational movement.
E. A second suspension element can have a variable-distance attachment to a hoist body. For example, a motor of the hoist body can be configured to change the position of the second suspension element relative to the hoist body. For example, the second suspension element can be a hook attached to the hoist body via a chain and the motor can change the extension of the chain from the hoist body.
F. A load measurement arrangement can be configured to determine the weight of a load suspended by a hoist.
G. A load measurement arrangement can comprise a load element and one or more sensors configured to measure a load applied to the load element. The one or more sensors may be more than four sensors.
H. A load measurement arrangement can comprise a load element and one or more sensors, and a tilt sensor.
I. The one or more sensors can be located within the load element.
J. A load measurement arrangement can be configured to transmit measurement information to a distant location. The load measurement arrangement is configured to only provide measurement information at a location distant to a load element.
K. A load measurement arrangement can be configured to hold a load element in a static position (i.e., unable to translate or rotate). The load measurement arrangement may be configured to only allow forces to be applied to the load element in a single direction, for example only allowing the load element to be subject to compressive forces.
L. A load measurement arrangement can comprise at least one power source. The load
measurement arrangement may comprise a battery unit as a backup power source. The load measurement arrangement comprises two power sources, a first power source receiving power from the hoist body and a second power source constituted by a battery unit as a backup power source. It is also feasible that a load measurement arrangement could comprise only a single power source (either from the hoist body or a battery unit).
M. A load measurement unit can comprise a control unit. The control unit can comprise an electronic circuit. The control unit can be configured to receive power from one or more power sources. The control unit can be configured to receive measurement information from the one or more sensors. The control unit can be configured to transmit measurement information to a distant location. This may be through a wired connection or a wireless transmitter. The control unit can be located external to the housing. The control unit may be located within a hoist body. The control unit can be connected via a wire to the one or more sensors which are located inside the load element. The control unit can be configured to halt or modify a motor or a hoist body’s operative state. For example, the control unit can be configured to halt operation of a motor in the case of a detected undesired load.
N. A tilt sensor may be located within a control unit.
O. A load measurement arrangement can comprise an anti-rotation element configured to prevent rotation of a load element. According to one example, the anti-rotation element can be one or more outwardly projecting projections and a suspension bridge can have one or more recesses configured for receiving the one or more projecting portions.
P. A load measurement arrangement can comprise a lug nut and corresponding pin configured to secure a load element to a suspension bridge. The pin can extend through a pin hole formed in the second end of the load element to prevent the lug nut from loosening.
Q. A load element can be located between a hoist body and a fixed distance first suspension element such that all compressive forces between the hoist body and the first suspension element are applied to the load element.
R. A suspension bridge can be located between a load element and a hook portion of a first suspension element.
S. The orientation of the load element or load measurement arrangement can be such that it minimizes any bending or non-axial forces. For example, the load element can be configured to extend perpendicular or substantially perpendicular to a longest dimension of the hoist body. For example, the load element can be configured to extend perpendicular with a shaft portion of a hook which is adjacent to the load element.
T. One or more sensors can be configured to measure a load applied to the load element and transmit the load measured. The one or more sensors may be configured to measure strain. BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the subject matter of the present application, and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which:
Fig. 1 is a schematic perspective view of a hoist in accordance with the presently disclosed subject matter;
Fig. 2 is a schematic perspective view of a first suspension element and load measuring arrangement of the hoist in Fig. 1 ;
Fig. 3 is an exploded view of the first suspension element and load measuring arrangement in Fig. 2, except for the electronic components thereof;
Fig. 4A is an upper perspective view of a suspension bridge of the load measuring arrangement in Fig. 2;
Fig. 4B is a lower perspective view of the suspension bridge in Fig. 4A; Fig. 4C is a side view of the suspension bridge in Fig. 4A;
Fig. 4D is a bottom view of the suspension bridge in Fig. 4A;
Fig. 5A is a perspective view of a load element of the load measuring arrangement in Fig. 2; Fig. 5B is a side view of the load element in Fig. 5A;
Fig. 5C is a top view of the load element in Figs. 5A and 5B, further schematically showing a plurality of sensors and attached wires;
Fig. 6 is a partial section view of the first suspension element and load measuring arrangement in Fig. 2, excluding the electronic components thereof; and
Fig. 7 is an exploded view of the first suspension element and a modification of the load measuring arrangement in Fig. 2.
DETAILED DESCRIPTION
Reference is made to Fig. 1 which illustrates an example hoist 10. The hoist 10 comprises a hoist body 12, a first suspension element 14 secured to the hoist body 12, a motor 16 (schematically shown in dashed lines), a chain 18 engaging the motor 16, and a second suspension element 20 attached to the chain 18.
There is further provided a controller 22 for an operator to operate the hoist 10, e.g., to vary the second suspension element 20 position relative to the hoist body 12, and a container 23 for collecting therein the chain 18. The first and second suspension elements 14, 20 may be hooks. Referring also to Fig. 3, (using the first suspension element 14 as an example, noting that both are identical) the first suspension element 14 comprises a hook portion 24, an integrally formed shaft portion 26, and a latch portion 28.
The first suspension element 14 may be attached to a suspension bridge 30 in a manner that it can only rotate relative to the suspension bridge 30. The suspension bridge 30 is firmly secured to the hoist body 12 such that it cannot move relative thereto. Accordingly, the first suspension element 14 is attached to the hoist body 12 at a constant or fixed distance thereto, the distance being substantially adjacent thereto.
In contrast, the second suspension element 20 can be brought to different distances from the hoist body 12 upon operation of the motor 16.
The hoist 10 comprises a load measurement arrangement 32 (which comprises all elements shown in Fig. 2 except for the first suspension element 14).
Referring to Fig. 5C, the load measurement arrangement 32 comprises in a broadest sense a load element 34 and one or more sensors 36 (which in this example are six equally circumferentially spaced strain gauges 36A, 36B, 36C, 36D, 36E, 36F).
The load measurement arrangement 32 can further comprises electronic components. For example, each of the sensors can be connected with one or more wires 37. Referring to all figures, the load measurement arrangement 32 can comprise a control unit 38 (for example located in the hoist body 12 as shown in Fig. 1) comprising an electronic circuit 40 (Fig. 2), wiring 42 connecting the one or more sensors 36 to the control unit 38 for transfer of measurement information, further wiring 44 for transmitting information from the circuit 40 to an external location (not shown), wiring 46 for receiving power from a primary power source (not shown) and extending to the control unit 38, a back-up battery power source 48, and wiring 50 connecting it to the control unit 38. It will be understood that the presently disclosed subject matter is primarily concerned with accurate load measurement which is primarily related to the load element 34 and position thereof, and hence the electronic components described should be considered as non- limiting examples.
Referring to Fig. 3, the load measurement arrangement 32 can further comprise a securing arrangement (all elements designated as “52”) for securing the load element 34 to the first suspension element 14 and suspension bridge 30.
Since the suspension bridge 30 is configured to hold the load element in place, it is also considered part of the load measurement arrangement 32 and not the securing arrangement 52.
While the securing of the load element 34 to the first suspension element 14 and suspension bridge 30 could be done in different ways, the exemplified embodiment are not meant to be limiting. More precisely the securing arrangement 52 comprises a lug nut 54, and a pin 56 mounted in a slot 58 of the lug nut 54 for halting rotational movement relative to the load element 34.
Referring to Figs. 4A-4D, the suspension bridge 30 comprises a cover wall 60 and a peripheral wall 62 extending adjacent the perimeter of the cover wall 60. The cover wall 60 has an outer surface 64 facing towards the first suspension element 14 (e.g., Fig. 6).
First and second bores 66, 68 extend through the cover wall 60 at opposite ends of the suspension bridge 30 and are configured to receive screws (not shown) therethrough to secure the suspension bridge 30 to corresponding threaded bores (not shown) of the hoist body 12. Between the first and second bores 66, 68 there is a securing section 70, a chamber section 72, and a side wall 74 separating them. The securing section 70 is configured to secure the first suspension element 14 to the suspension bridge 30 and thus has a suspension aperture 76 formed in the cover wall 60 which is configured for receiving the shaft portion 26 therethrough.
A notch 78 is formed in the side wall 74. This is used to prevent rotation of the load element 34 as described hereinafter. The notch 78 provides a further function of allowing the wiring 42 (Fig. 2) from the load element 34 to extend therethrough and into the hoist body 12.
Referring to Figs 5A-5C the load element 34 34 can comprise parallel top and bottom surfaces 80, 82 and an external peripheral surface 84 extending therebetween.
The load element 34 may be ring-shaped about a central axis Ac.Accordingly, the external peripheral surface 84, and a corresponding internal peripheral surface 85, are both cylindrical.
The sensors 36 may be equally circumferentially spaced apart; for example, in the example described herein with reference to an illustrated in the accompanying figures, each of the six sensors are spaced from adjacent sensors by an angle of 60°about the central axis Ac.
The load element 34 further comprises an anti-rotation element 86, which may be a single outwardly radially projecting projection. As shown in Fig. 2, the anti-rotation element 86 is sized to fit in the notch 78.
The inner peripheral surface 85 forms a through-hole 88 sized to receive the shaft portion 26.
The external peripheral surface 84 is formed with an aperture 89 via which the wire 42 can exit the load element 34.
The lug nut 54 further comprises an external connection arrangement 55 (such as hexagonally arranged surfaces) and an internal threading 57.
Referring to Figs. 3 and 6, the assembly of the components will now be described in more detail. The first suspension element 14 comprises the shaft portion 26 which in turn comprises an external threading 90 and a pin hole portion 92 for receiving the pin 56.
Firstly, the load element 34 is inserted in the suspension bridge 30 such that the anti- rotation element 86 is located in the notch 78 to prevent rotation of the load element 34 relative to the suspension bridge 30.
The shaft portion 26 is then inserted through the suspension aperture 76 of the suspension bridge 30, and then the load element’s through-hole 88, and finally the external threading 90 of the shaft portion 26 is threaded to the corresponding internal threading 57 of the lug nut 54 thereby securing the first suspension element 14 to the suspension bridge 30.
The pin 56 is then inserted in the pin hole portion 92 to prevent further relative rotation of the lug nut 54 and shaft portion 26.
Irrespective of the precise securing arrangement, the first suspension element 14 is now held to the suspension bridge 30 yet can rotate relative thereto. It will be understood that the rotation capability is an option, and modification in which such rotation is constrained may be provided without departing from the scope of the presently disclosed subject matter, mutatis mutandis.
In operation, the first suspension element 14 is suspended from a support structure (not shown) and the second suspension element suspends a load (not shown). It will be understood that these functions could be reversed.
The controller 20 is used to change the height of the load by, for example, shortening the second suspension element’s 20 distance to the hoist body 12.
In such situation the entire weight of the load is suspended by the first suspension element 14 and consequently the load element 34 is brought into compression with the force being axially directed along the central axis Ac thereof.
Whether or not the first suspension element 14 rotates relative to the load element, this force remains effectively unaffected.
The sensor 36, in this non-limiting example, measures the strain on the load element 34 and transmits the information to the control unit 38 which processes it and, for example, transmits it to an appropriate display unit (not shown) for an operator.
To further improve the accuracy of the load measurement a tilt sensor schematically shown in Fig. 2 and designated“94” may be provided.
Referring to Fig. 1, when the chain 18 is moved by the motor 16, different amounts of the chain 18 are collected in the container 23. This consequently tilts the hoist body 12. Thus, provision of a tilt sensor 94 configured to measure a deviation of the load element 34 (or hoist body 12) from a vertical orientation allows the circuit 40 to correct an error of measurement caused by the tilting of the hoist body 12, which may improve the accuracy of the load measurement.
Reference is made to Fig. 7, which illustrates a modification of the load measuring arrangement 32 described above with reference to and illustrated in Figs. 1 through 6. According to this modification, a first suspension element 114 is provided comprising a hook portion 124, an integrally formed shaft portion 126, and a latch portion 128.
The first suspension element 114 may be attached to a housing 130 in a manner that it can only rotate relative thereto. The housing 130 may be firmly secured to a hoist body (not illustrated) such that it cannot move relative thereto. Accordingly, the first suspension element 114 is attached to the hoist body at a constant or fixed distance thereto, the distance being substantially adjacent thereto.
A load measuring arrangement 132 is provided, comprising a load element 134 and a securing arrangement 152. The load element 134 may be provided as described above with reference to and illustrated in the accompanying drawings, for example comprising one or more sensors and suitable electronic components (not illustrated). The securing arrangement 152 may comprise a lug nut 154 and a pin 156, mounted in a slot 158 formed in the lug nut for preventing rotational movement relative to the load element 134, for example as described above with reference to and illustrated in the accompanying drawings.
The load measuring arrangement 132 may further comprise one or more bearings. For example, one or more disc bearing 200 may be provided about the shaft portion 126 of the first suspension element 114, facilitating smooth rotation thereof about a central axis. The disc bearing 200 may comprise a single piece of smooth material such as a urethane, or may comprise a ball bearing, roller bearing, or any other suitable arrangement.
The load measuring arrangement 132 may further comprise a spherical bearing 202, for example between the disc bearings 200 and the load element 134. The spherical beating 202 provides rotational freedom, which may facilitate an increased accuracy in the load measurement by the load element 134.
It will be appreciated that the modification described above with reference to and as illustrated in Fig. 7 may comprise any of the corresponding features described above with reference to and as illustrated in Figs. 1-6, mutatis mutandis. Operation of a hoist comprising the load element 134 according to the modification described above with reference to and as illustrated in Fig. 7 is similar to that described above with reference to and as illustrated in Figs. 1-6.
Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations, and modifications can be made without departing from the scope of the presently disclosed subject matter, mutatis mutandis.

Claims

1. A motorized hoist comprising:
a hoist body comprising a motor;
a first suspension element attached at a fixed distance to the hoist body and configured for attachment to a first external body;
a second suspension element having a variable-distance attachment to the hoist body such that the motor is configured to change the position of the second suspension element relative to the hoist body, the second suspension element also being configured for attachment to a second external body; and
a load measurement arrangement configured to determine the weight of a load suspended by the hoist;
the load measurement arrangement comprising:
a load element; and
one or more sensors configured to measure a load applied to the load element and transmit information regarding the load measured;
wherein said first suspension element is attached at a fixed distance with said load element being located between the hoist body and the first suspension element such that all compressive forces between the hoist body and the first suspension element are applied to the load element.
2. The motorized hoist according to claim 1, wherein the load measurement arrangement further comprises a suspension bridge, and wherein the first suspension element is a hook comprising a hook portion and shaft portion and the fixed-distance attachment includes the load element being mounted to the shaft portion with the suspension bridge being closer to the hook portion than the load element.
3. The motorized hoist according to any one of claims 1 and 2, wherein the load measurement arrangement further comprises a tilt sensor configured to measure deviation of the load element from a vertical orientation.
4. The motorized hoist according to claim 3, wherein said tilt sensor comprises an accelerometer.
5. The motorized hoist according to any one of the previous claims, wherein the load measurement arrangement is configured to allow forces to be applied to the load element in a only single direction.
6. The motorized hoist according to any one of the previous claims, wherein the load element is configured to extend substantially perpendicular to a longest dimension of the hoist body.
7. The motorized hoist according to any one of the previous claims, wherein the load measurement arrangement is configured to receive power from a primary power source.
8. The motorized hoist according to claim 7, the load measurement arrangement further comprising a battery unit constituting a backup power source.
9. The motorized hoist according to any one of claims 7 and 8, wherein said primary power source receives power from the hoist body.
10. The motorized hoist according to any one of the previous claims, said load measurement unit further comprising a control unit.
11. The motorized hoist according to claim 10, said control unit comprising an electronic circuit.
12. The motorized hoist according to any one of claims 10 and 11, said control unit being connected to the one or more sensors via one or more wires.
13. The motorized hoist according to any one of claims 10 through 12, the control unit being configured to receive measurement information from the one or more sensors.
14. The motorized hoist according to any one of claims 10 through 13, wherein the control unit is configured to transmit measurement information to a remote location.
15. The motorized hoist according to claim 14, wherein the transmission of measurement information is through a wired connection or a wireless transmitter.
16. The motorized hoist according to any one of claims 10 through 15, the control unit being configured to halt operation of the motor when an undesired load is detected.
17. The motorized hoist according to any one of claims 10 through 16 when dependent on any one of claims 3 and 4, wherein the control unit comprises said tilt sensor.
18. The motorized hoist according to any one of claims 10 through 17, wherein the control unit is configured to halt or modify an operative state of said motor and/or said hoist body.
19. The motorized hoist according to any one of the preceding claims, wherein said first suspension element is rotatable.
20. The motorized hoist according to any one of the preceding claims, wherein said first suspension element is a hook comprising a hook portion and a shaft.
21. The motorized hoist according to claim 20, wherein the load element is configured to extend perpendicularly to the shaft portion of a hook, said hook being adjacent to the load element.
22. The motorized hoist according to any one of the preceding claims, wherein said load measurement arrangement is configured to facilitate remote monitoring of the determined weight.
23. The motorized hoist according to any one of the preceding claims, wherein said load measurement arrangement is configured to facilitate automated monitoring of the determined weight.
24. The motorized hoist according to any one of the preceding claims, wherein said one or more sensors comprises one or more strain gauges.
25. The motorized hoist according to any one of the preceding claims, wherein said load measurement arrangement is configured to transmit information regarding the load measured to a remote location.
26. The motorized hoist according to claim 25, wherein the load measurement arrangement is configured to provide measurement information only at a location distant from the load element.
27. The motorized hoist according to any one of the preceding claims, the load measurement arrangement further comprising a lug nut and corresponding pin configured to secure the load element to a suspension bridge.
28. A hoist load measurement arrangement comprising:
a load element;
one or more sensors configured to measure a load applied to the load element and transmit the load measured;
a first suspension element; and
a suspension bridge;
wherein the load element is located relative to the suspension bridge and the first suspension element such that all compressive forces applied by the first suspension element to the suspension bridge are applied to the load element.
29. The hoist load measurement arrangement according to claim 28, wherein the load element comprises a ring-shape.
30. The hoist load measurement arrangement according to claim 29, comprising a plurality of said sensors circumferentially spaced apart on the ring-shape.
31. The hoist load measurement arrangement according to claim 30, wherein said sensors are spaced equally apart.
32. The hoist load measurement arrangement according to any one of claims 28 through 31, wherein the load element comprises at least one projection or recess configured to prevent rotation of the load element relative to the other components of the hoist load measurement arrangement.
33. The hoist load measurement arrangement according to claim 32, wherein the at least one projection or recess is at least one projection, and is configured to prevent rotation of the load element relative to the other components of the hoist load measurement arrangement, and wherein the projection is an outwardly projecting projection.
34. The hoist load measurement arrangement according to claim 33, wherein the outwardly projecting projection extends outwardly in a radial direction.
35. The hoist load measurement arrangement according to any one of claims 28 through 34, comprising at least four of said sensors.
36. The hoist load measurement arrangement according to claim 35, comprising at least six of said sensors.
37. The hoist load measurement arrangement according to any one of claims 28 through 36, wherein the one or more sensors are located within the load element.
38. The hoist load measurement arrangement according to any one of claims 28 through 37, being configured to receive power from a primary power source.
39. The hoist load measurement arrangement according to claim 38, further comprising a battery unit constituting a backup power source.
40. The hoist load measurement arrangement according to any one of claims 28 through 39, further comprising a tilt sensor configured to measure deviation of the load element from a vertical orientation.
41. The hoist load measurement arrangement according to claim 40, wherein said tilt sensor comprises an accelerometer.
42. The hoist load measurement arrangement according to any one of claims 28 through 41, being configured to allow forces to be applied to the load element in a only single direction.
43. The hoist load measurement arrangement according to any one of claims 28 through 42, further comprising a control unit.
44. The hoist load measurement arrangement according to claim 43, said control unit comprising an electronic circuit.
45. The hoist load measurement arrangement according to any one of claims 43 and 44, said control unit being connected to the one or more sensors via one or more wires.
46. The hoist load measurement arrangement according to any one of claims 43 through 45, the control unit being configured to receive measurement information from the one or more sensors.
47. The hoist load measurement arrangement according to any one of claims 43 through 46, wherein the control unit is configured to transmit measurement information to a remote location.
48. The hoist load measurement arrangement according to claim 47, wherein the transmission of measurement information is through a wired connection or a wireless transmitter.
49. The hoist load measurement arrangement according to any one of claims 43 through 48 when dependent on any one of claims 40 and 41 , wherein the control unit comprises said tilt sensor.
50. The hoist load measurement arrangement according to any one of claims 28 through 49, wherein said first suspension element is rotatable.
51. The hoist load measurement arrangement according to any one of claims 28 through 50, wherein said first suspension element is a hook comprising a hook portion and a shaft.
52. The hoist load measurement arrangement according to claim 51 , wherein the load element is configured to extend perpendicularly to the shaft portion of the hook, said hook being adjacent to the load element.
53. The hoist load measurement arrangement according to any one of claims 28 through 52, being configured to facilitate remote monitoring of the determined weight.
54. The hoist load measurement arrangement according to any one of claims 28 through 53, being configured to facilitate automated monitoring of the determined weight.
55. The hoist load measurement arrangement according to any one of claims 28 through 54, wherein said one or more sensors comprises one or mor strain gauges.
56. The hoist load measurement arrangement according to any one of claims 28 through 55, being configured to transmit information regarding the load measured to a remote location.
57. The hoist load measurement arrangement according to claim 56, being configured to provide measurement information only at a location distant from the load element.
58. The hoist load measurement arrangement according to any one of claims 28 through 57, further comprising a lug nut and corresponding pin configured to secure the load element to a suspension bridge.
PCT/IL2019/051375 2018-12-17 2019-12-16 Motorized hoist with high precision load measurement arrangement WO2020129055A1 (en)

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