Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C17/00—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces
  • B05C17/005—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces for discharging material from a reservoir or container located in or on the hand tool through an outlet orifice by pressure without using surface contacting members like pads or brushes
  • B05C17/00576—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces for discharging material from a reservoir or container located in or on the hand tool through an outlet orifice by pressure without using surface contacting members like pads or brushes characterised by the construction of a piston as pressure exerting means, or of the co-operating container
  • B05C17/00579—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces for discharging material from a reservoir or container located in or on the hand tool through an outlet orifice by pressure without using surface contacting members like pads or brushes characterised by the construction of a piston as pressure exerting means, or of the co-operating container comprising means for allowing entrapped air to escape to the atmosphere

Definitions

• the present invention relates to a dispensing assembly comprising a piston and a membrane.
• the masses can be a so-called one-component mass, this means single component materials that e.g. harden via a chemical reaction which is brought about either by an external energy source, such as UV light or heat, or e.g. due to moisture etc. present in the surroundings of the position of application or air.
• an external energy source such as UV light or heat
• Typical applications of one component materials can be found e.g. in the dental field or in the building industry, for example to bond products such as windows and concrete elements, or to provide seals between different components.
• the materials to be dispensed are typically a matrix material and a hardener.
• the filled cartridges come in different ratios referred to as 1:1, 2:1, 4:1 and 10:1 etc., the numbers specifying the ratios of the amounts of each of the two materials that are to be dispensed.
• the reason for these different ratios is to allow a wide variety of different compositions to be mixed and dispensed. For example some compositions require more hardener and some require less hardener. Also some compositions require more mixing. Mixing tips are known from the prior art which are adapted to mix the compositions as they exit the cartridge.
• Two-component materials are typically used as impression materials, e.g. on the formation of dental impressions, as a cement material for prosthetic restorations, as a temporary cement for trial cementing restorations or for cementing temporary crowns. Further applications of two-component materials are in the building industry where they are e.g. used as a replacement for mechanical joints that corrode over time. Adhesive bonding can be used to bond products such as windows and concrete elements.
• the use of multi-component protective coatings for example moisture barriers, corrosion protection and anti-slip coatings, is also becoming increasingly common. Examples of flowable materials which can be used are, for example, distributed by the company Coltene using the tradename AFFINIS ® or by the company DMG using the tradename PermaCem.
• One-component and multi-component materials are frequently very expensive and thus it is desired to increase the storage life of these materials, particularly if the cartridges and the materials are designed not just for a single use, but such that they can be used a multiple amount of times over considerable periods of time of e.g. days, weeks or even months.
• the cartridges to be filled have to be made from materials which do not react with the masses stored therein. Moreover, the cartridges have to be clean, i.e. they should not include any water residue or air etc., in particular in connection with the storage of single component masses.
• the cartridges are typically filled either via their outlet with the piston already being positioned in the cartridge or the cartridge is filled from the end where the piston is normally received before the installation of the piston.
• Such a dispensing assembly comprises a piston and a membrane, wherein the piston has a dispensing end and an actuation end, wherein the actuation end can be acted on to move a piston for dispensing, wherein the membrane is arranged to cover at least a part of the dispensing end.
• This membrane can move relative to dispensing end on assembling a dispensing assembly to reduce the amount of air included in the cartridge.
• the membrane can either be attached to the dispensing end or moveable relative thereto.
• dispensing end is that end of the piston that once assembled in a cartridge faces the material to be dispensed.
• actuation end is arranged at the opposite side of the piston to the dispensing end and can be acted on by e.g. a plunger to move a piston in a cartridge-
• the membrane may be connected to the dispensing end. In this way the membrane can be fixed relative to the cartridge in order to permit air to flow into a space between the membrane and piston to act as a buffer on the material stored in a cartridge.
• the membrane may be fixedly connected to the piston. By fixedly connecting the membrane to the cartridge one can ensure that the space is hermetically sealed off with respect to a cartridge chamber.
• the membrane may be bonded to the piston, for example by means of ultrasonic welding, overmolding and/or an adhesive bond. Such bonds ensure the hermetic seal if required and reduce the amount of air present in a cartrdige.
• the membrane may be arranged to cover at least 60% and at most 90 % of the actuation end. In this way a space formed between the membrane and the piston can be maximized.
• a material of the membrane may be selected from the group of members comprising PTFE, PEEK, POM, Polyamide, PPS, PPA, PET, PPE and blends of one or more of the foregoing.
• the dispensing assembly may further comprise a cartridge filled with a material and the piston may then be arranged within the cartridge.
• cartridges are frequently used to store liquid flowable, frequently pasty or viscous to highly viscous substances and to dispense them for the respective application as required. Examples for such substances are joint sealing compounds, compounds for chemical dowels or chemical anchors, adhesives, pastes or impression materials in the dental sector.
• Fig. 1A & B show first views of a cartridge 10 for storage and dispensing of materials M from a chamber 12 of the cartridge 10.
• the cartridge 10 comprising an outlet 20 having an outlet passage 24 extending from an inlet opening 36 arranged at an end face 34 of the cartridge 10 bounding the chamber 12 to an outlet opening 38 projecting away from the cartridge 10 (see e.g. Fig. 3A ).
• the plug 16 is a component separate from the closure ring 14 in the present example. It should be noted in this connection that the plug 16 could also be integrally formed with the closure ring 14 (not shown).
• the cartridge 10 further comprises cartridge walls 18 extending from the end face 34 to a rear end 92 of the cartridge 10.
• the rear end 92 comprises an opening into which a piston 60 (see e.g. Figs. 5, 6 or 7A ) can be inserted.
• the cartridge 10 comprises tapered walls 96 at the rear end 92. It should be noted in this connection that such tapered walls 96 are not required for insertion of the piston 60 they merely facilitate the insertion of the piston 60 into the cartridge chamber.
• Fig. 4A to C show views of the plug 16 for the outlet 20 of Fig. 3 .
• the plug 16 comprises a body 54 having a grip 52 for gripping the plug 16.
• the plug alignment means 26 extend in parallel to the stopper 30 from the abutment 32.
• the plug alignment means 26 can have a generally T-shaped cross-section, it should be noted that also other cross-sections, such as a cylindrical cross-section are likewise possible.
• the outlet passage 24 shown has a cone-shaped cross-section but can also have a cylindrical cross-section in the region of the inlet opening. If provided, the cylindrical cross-section in the region of the inlet opening has a smaller inner diameter than the cylindrical or cone shaped section in the region of the outlet opening.
• the cylindrical or cone shaped cross-section in the region of the outlet opening 38 can extend over a length of 20 to 80% of a length of the outlet passage 24 from the outlet opening 38 towards the inlet opening 36. In this way an improved seal can be provided in the region of the outlet 20 reducing the amount of air that can be trapped between the plug 16 and the cartridge chamber 12.
• the cylindrical cross-section in the region of the inlet opening 36 can extends over a length of 20 to 80% of a length of the outlet passage 24 from the inlet opening 36 towards the outlet opening 38. In this way an improved seal can be provided in the region of the outlet 20 reducing the amount of air that can be trapped between the plug 16 and the cartridge chamber 12.
• the outlet passage 24 can has a truncated cone shaped cross-section in the region of the inlet opening 36. In this way an improved seal can be provided in the region of the outlet 20 reducing the amount of air that can be trapped between the plug 16 and the cartridge chamber 12.
• the outlet passage 24 can have an outer diameter selected in the range of 6 to 10 mm at the outlet opening 38.
• the outlet passage 24 can have an inner diameter selected in the range of 4 to 8 mm at the outlet opening 38.
• the outlet passage 24 comprises no inner thread. In this way an improved seal can be provided in the region of the outlet 20 reducing the amount of air that can be trapped between the plug 16 and the cartridge chamber 12.
• a material of the cartridge may be selected from the group of members comprising PTFE, PEEK, POM, Polyamide, PPS, PPA, PET, PPE and blends of one or more of the foregoing.
• Fig. 5 shows a view of a first kind of dispensing assembly 100.
• the dispensing assembly 100 comprises the piston 60 and a membrane 80.
• the piston 60 has a dispensing end 66 and an actuation end 64, wherein the actuation end 64 can be acted on to move the piston for dispensing, wherein the membrane 80 is arranged to cover at least a part of the dispensing end 64.
• the membrane 80 is fixedly connected to the dispensing end 66.
• the membrane is bonded to the piston, for example by means of ultrasonic welding, overmolding and/or an adhesive bond.
• the membrane 80 comprises an elastomer.
• the membrane 80 can also be formed by a multi-layered film as shown e.g. in Fig. 6 .
• the multi-layered film comprises two or more layers with the two or more layers being connected to one another.
• the piston cover 70 comprises a venting pin 68 configured to lift the piston cover 70 from the piston body 72 during a venting process.
• a material of the piston 60 is selected from the group of members comprising PTFE, PEEK, POM, PA, PPS, PPA, PET, PPE and blends of one or more of the foregoing.
• a material of the membrane may be selected from the group of members comprising PTFE, PEEK, POM, Polyamide, PPS, PPA, PET, PPE and blends of one or more of the foregoing.
• the piston 60 of Fig. 7 can also comprise a venting passage 74 extending from the actuation end 64 to the dispensing end 66 for venting via the venting channel 75.
• the dispensing end 66 comprises one or more venting channels that can extending over the concave shaped portion 84 towards the venting passage 74.
• the piston further comprises a venting plug 82 arranged at the actuation end 64 for sealing off the buffer space 48 of the piston 60 when inserted into the cartridge 12.
• venting plug 82 is moveable with respect to the actuation end 64.
• the piston of Fig. 7 can also comprise one, two, three or more sealing elements arranged on a peripheral outer surface of the piston 60.
• sealing elements can comprise sealing lips 62 and/or O-rings 98.
• An inner diameter of the venting passage can be selected in the range of 0.1 to 5 mm, preferably in the range of 0.2 to 4 mm.
• a material of a least the concave shaped portion of the piston can be selected from the group of members comprising PTFE, PEEK, POM, Polyamide, PPS, PPA, PET, PPE and blends of one or more of the foregoing.
• the piston of Figs. 7 and 8 is inserted in a cartridge 10 having a dome shaped end face projecting into the cartridge chamber.
• This dome shaped end face is shaped and formed complementary to the piston 60 in order to minimize an amount of air that can be trapped between the piston 60 and the end face 34 of the cartridge 10.
• Fig. 10 shows a process chart for filing a dispensing assembly 100 such as the assembly shown in Fig. 5 and 6 .
• the method of filling comprising the steps of:
• the piston 60 can comprises a venting pin and the method further comprises the step of actuating said venting pin in order to release over pressure from within the cartridge 10.
• the piston 60 comprises the plug 82 and the plug 82 is moved relative to a piston body 72 in order to close the piston 60.
• Figs. 10 and 11 can be mixed, e.g. the cartridge and piston of Figs. 5 and 6 can also be subjected to centrifuging as shown in Fig. 11 and the piston of Figs. 7 to 9 can have the vacuum released as indicated in Fig. 10 .

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Containers And Packaging Bodies Having A Special Means To Remove Contents (AREA)

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Publications (1)

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Citations (2)

• 2024
  • 2024-01-09 EP EP24150942.1A patent/EP4585318A1/de active Pending
  • 2024-12-16 WO PCT/EP2024/086522 patent/WO2025149305A1/en active Pending

Patent Citations (2)

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