Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D30/00—Producing pneumatic or solid tyres or parts thereof
  • B29D30/02—Solid tyres ; Moulds therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C19/00—Tyre parts or constructions not otherwise provided for
  • B60C19/08—Electric-charge-dissipating arrangements

Definitions

• the invention refers to a tread for an industrial truck wheel or an industrial truck roll, which tread counteracts the generation of electrostatic charge.
• the invention further refers to an industrial truck wheel with such a tread as well as an industrial truck comprising such an industrial truck wheel.
• the invention refers to a method for reducing the generation of static electrostatic charge of an industrial truck wheel or an industrial truck roll.
• treads become electrostatically charged at driving.
• the electrostatic charge arises in the composite material of the treads when loading in contact with the floor.
• the charge is thereafter transferred via the rim to which the treads are attached to the chassis of the industrial truck as well as the electric system of the industrial truck.
• the conductive wheels shall have a resistance below
• the anti-static wheels shall have a resistance of between 100 kohm and 10 mohm.
• Charge over 8 - 10 kV is not desirable as it can lead to sparks, discomfort, component damages as well as function disturbance.
• the pivoted wheels described in DE19858825 C2 have the disadvantages of, compared with conventional industrial truck wheels, being relatively expensive, give a less bearing capacity and have a shorter endurance.
• the goal with the present invention is to in a cost efficient manner reduce the electrostatic charge that can occur at a chassis of an industrial truck, without deteriorating the performance of the industrial truck.
• the goal has been achieved by providing a solid tread for an industrial truck wheel or an industrial truck roll, where at least one of the side surfaces of the tread has an electrically conductive coating, which reduces generation of electrostatic charge in the tread.
• the tread has the shape of a cylinder and its side surfaces are defined as the cylinder's both circular ends.
• the electrostatic charge at an industrial truck chassis is limited, which wheels of the industrial truck is provided with the inventive treads, to 2,5 - 5 kV. A charge within this range does not give rise to any of the above mentioned problems.
• the electrically conductive coating on the tread side surface suppresses the occurrence of electrostatic charge.
• the invention has the desired effect also when driving on electrically isolated grounds, for example plastics such as epoxy.
• Other advantages are that the tread only implies a marginal cost increase and does not affect the driving performance or the admissible c
• the effect of the invention is predictable as it is essentially not affected by varying air humidity.
• the invention can be applied on existing conventional industrial truck wheels by applying the coating.
• the invention has its best effect if the coating covers the entire tread side surface.
• the invention is however functioning to satisfaction even if the coating does not cover the entire side surface, which for example can be the case after the wear that occurs after a time period of operation.
• the coating can be applied such that it covers the entire side surface of the tread and also, thereby electrically contacts, overlaps the rim that the tread is mounted on. Further the coating can extend around the edge of the side surface to the outer surface of the tread, which is the side that in operation is facing the ground. In a corresponding manner the coating can be applied to the inside of the tread, which is the side that in operation is facing the rim.
• a simple and cost efficient manner to provide the tread with the electrically conductive coating is to cover both the tread side surface and the rim side surface with the coating. Through this is additionally achieved god electric contact between the tread and the rim.
• the invention functions at its best if the both of the side surfaces of the tread are covered with the electrically conductive coating.
• the effect of the invention can however also be achieved by coating only one of the side surfaces, which facilitates the production of the tread as only one side surface needs to be treated.
• the electrically conducting coating is of a colour that sharply deviates from the colour of the tread, it is possible to visually in a simple manner determine that an industrial truck is provided with the tread and by this is not heavily electrostatically charged. This is of advantage in operations having certain areas to which only vehicles with low charge are permitted.
• the deviating colour serves as a distinct marking when handling wheels before mounting on an industrial truck.
• the tread can be made in polyurethane which implies good admissible loading and good driving performances.
• the effect of the invention can however in principal always be reached with a tread from other materials, such as rubber.
• the goal of the invention has further been achieved through an industrial truck wheel or an industrial truck roll that has the said tread, and through an industrial truck with such an industrial truck wheel or such an industrial truck roll.
• the invention functions at its best if all wheels and/or rolls are of the type according to the invention.
• the goal of the invention has finally been achieved by providing of a method to reduce generation of electrostatic charge at an industrial truck wheel or an industrial truck roll when loaded in connection with driving of an industrial truck that is carried by the industrial truck wheel or the industrial truck roll.
• the method comprises the step of coating at least one side surface of the solid tread of the industrial truck wheel or the industrial truck roll with an electrically conducting coating.
• figure 1 a plane view and a side view of an industrial truck wheel with a tread according to the present invention
• figure 2 side views from further embodiments of the present invention
• figure 3 a comparison in static charge when using a conventional wheel and a wheel
• Figure 1 shows in a schematic manner an industrial truck wheel 10 or an industrial truck roll 10.
• the difference between an industrial truck wheel and an industrial truck roll is mainly that an industrial truck wheel is larger and designed to carry a larger load.
• An industrial truck wheel often operates as a powered and steering wheel, while an industrial truck roll often operates as a support leg wheel.
• an industrial truck wheel often operates as a powered and steering wheel, while an industrial truck roll often operates as a support leg wheel.
• the invention is functions in the same manner with an industrial truck roll.
• the industrial truck wheel 10 On the left side of figure 1 the industrial truck wheel 10 is shown in a plane view.
• the industrial truck wheel 10 has a rim 15 to which a tread 20 is mounted.
• On the right hand side of figure 1 the same wheel 10 is shown seen in the travel direction.
• the tread has the shape of a cylinder, more precisely a hollow cylinder.
• the in cross section circularly shaped tread 20 of the wheel 10 has a first side surface 20a and a second side surface 20b.
• To the first side surface 20a of the tread is a first coating 30a applied.
• the first coating 30a covers the entire first side surface 20a of the first tread.
• the corresponding is valid for the second side surface 20b of the second tread, where a second coating 30b has been applied.
• Figure 2 discloses different variants when it comes to the coating of the tread 20 and the rim 15 seen in the direction of travel.
• a wheel 10 is illustrated with different coating on the first side surface 20a of the tread 20 and the second side surface 20b respectively.
• the first coating 30a covers the entire side surface 20a of the tread and also overlaps the rim 15.
• the second coating 30b covers the entire second side surface 20b of the tread and also the entire rim 15.
• a wheel 10 is illustrated that is only covered on one side surface.
• the coating 30a extends over the entire first side surface 20a and around the peripheral outer edge to the outer surface 20c of the tread, which is the surface that is facing the ground.
• FIG. 2 To the right of figure 2 is illustrated a further alternative for the coating 30a, 30b.
• the same coating is used on the first and second side surfaces of the tread 20.
• the coatings 30a, 30b extend over the entire first and second side surfaces and around their peripheral outer edges to the outer surface 20c of the tread.
• the coatings 30a, 30b are further applied on the inner surface 20d of the tread, which is the side which is facing the rim 15.
• figures 1 and figures 2 illustrate several alternatives when considering the extension of the coating on the wheel.
• the coating can be applied exclusively to the tread, or on the tread and the rim.
• the coating can be of the same type on both sides, or be of different type on the sides.
• FIG 3 discloses the result of real measurements, where all wheels 10 of an industrial truck have carried treads with an electrically conducting coating 30a, 30b on both sides 20a, 20b of the tread, see figure 1.
• a - D are disclosed a dashed bar and a non-dashed bar.
• the dashed bars represent the charge that arises when operating wheels 10 according to the present invention, while the other bars represent ordinary wheels.
• the wheels according to the present invention have a favourable effect on each of the grounds A - D.
• the bars A concern the electrostatic charge that arises when operating on a first ground.
• the wheels of the invention bring about that the charge has been reduced by approximately 55 %.
• the bars B represent results measured when operating on a second ground, where the charge is reduced by 75 %.
• C represents operating on a third ground and a reduction of approximately 90 % has been established.
• the bars D represent operating on a fourth ground and show a reduction of approximately 70 %.
• FIG. 3 discloses that cases B, C and D imply charge in this interval, if conventional industrial truck wheels are used. In all cases the usage of the wheels of the invention has reduced the charging to an acceptable level.
• the invention implies coating of a tread with an electrically conductive coating.
• the coating can for example be Graphite 33 from Griffin Chemie.
• the coating can for example be sprayed or painted on the tread, or on the tread and the rim that carries the tread. Through this the coating can, according to the embodiments above, be applied to one or both side surfaces of the tread.
• the method can additionally comprise coating of the inner and/or outer surfaces of the tread.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Elimination Of Static Electricity (AREA)
• Tires In General (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Paints Or Removers (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=44262976

Family Applications (1)

Country Status (3)

Cited By (1)

Families Citing this family (1)

Family Cites Families (7)

• 2010
  • 2010-03-18 SE SE1050255A patent/SE534673C2/sv unknown
• 2011
  • 2011-03-17 EP EP11715776A patent/EP2547538A1/en not_active Withdrawn
  • 2011-03-17 WO PCT/SE2011/050292 patent/WO2011115564A1/en active Application Filing

Non-Patent Citations (1)

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