Tensioned printing screen frame, assembly and method

Abstract

A printing screen assembly, a frame for a printing screen and a method for the construction of the first two are disclosed. The printing screen assembly has a frame (310) having an elongate first frame member (320, 320a) and an elongate second frame member (320, 320b) parallel to and in fixed relationship with the first frame member (320, 320a); and respective first and second cantilevered tensioning devices (326) extending from each frame member (320) along its length. A predictable pre-tension can be applied by resiliently deflecting the tensioning devices (326) into contact with abutment arrangements (328) and securing the printing screen to an attachment portion (326b) of the first tensioning device (326a) whilst the first tensioning device (326) is in contact with the first abutment arrangement (326a). The frame can be formed by pre-selecting the resilience of the tensioning devices (326) so as to pre-select the tension applied when tensioning the printing screen in use.

Description

Technical Field

[0001] This invention relates to the field of high-precision screen printing, and particularly to the field of high-precision screen printing for applications such as solder paste printing. Background Technology

[0002] Screen printing is used in a range of industries to print images onto a substrate. A printing screen with orifices defining the image negative is stretched within a frame and placed on a substrate. Ink or other printing media is distributed onto the screen by moving rollers or squeegees (sometimes called squeegees) across its surface, causing the printing media to flow through the orifices and the image to be printed onto the substrate.

[0003] In certain technological applications, screen printing methods are used that require high dimensional accuracy and precise feature clarity. For example, high-precision screen printing is used to print electronic features, such as those required for modern batteries or printed electronic devices, sensor features, photovoltaic features, etc.

[0004] Conventional precision screen printing uses latex screens. A mesh material with a suitable mesh size (typically woven steel or titanium mesh) is selected, and the printing screen is constructed such that the mesh is held taut within a rigid frame. A layer of photopolymer precursor solution or suspension is applied to the mesh. The photopolymer is selectively cured to produce a negative of the desired printed pattern (e.g., using a UV laser, using pre-cut sheets, or a mask), and the uncured precursor is washed away, leaving the desired printed pattern defined on the screen by the mask-defined exposed areas of the mesh.

[0005] In alternative applications, such as when printing solder patterns onto a circuit board substrate, sheet materials such as polymers or more typically metal sheets are used, where the pattern is precisely cut (e.g., by laser cutting) into the sheet material.

[0006] Mesh or sheet printing screens must be tensioned to keep the mesh as flat as possible to prevent the printing medium from bunching up when the screen is removed after printing. Therefore, the screen is tensioned by being stretched and secured to a frame while under tension (before or after the pattern is formed in the printing screen).

[0007] While this arrangement relatively directly tensions the mesh or sheet printing screen, the resulting printing screen and frame assembly is relatively large, and therefore storing the printing screen assembly library can be problematic. Furthermore, removing the printing screen from the frame without damage is often impractical or impossible, especially for the thin sheets required for precision printing, resulting in high material and recycling costs.

[0008] Solutions for removably mounting screens to frames have been proposed. For example, DE102005054225 describes a sheet-like metal printing screen with an array of perforations around its periphery, which are secured to a support frame equipped with spring-loaded bias pins corresponding to the perforation array. While this arrangement allows for frame reuse, the frame itself is mechanically complex and costly to manufacture. Installation and removal of the printing screen are also relatively time-consuming due to the need for precise alignment of the perforations and pins. Furthermore, the tension applied to the screen by the frame cannot be easily adjusted to specific requirements.

[0009] WO2005046994 describes a removable wire mesh and frame, wherein a sheet metal wire mesh has lips along each edge to be hooked onto a movable member within the frame. The movable member is then biased to tension the wire mesh by pressurizing a bladder within the frame. While this method is mechanically simpler and easier to use, the frame requires constant maintenance of a pneumatic system, and the amount of tension is limited by the strength of the hook-like devices surrounding the perimeter of the wire mesh. This is particularly problematic for very thin wire mesh materials. Although the tension applied to the wire mesh by the frame can be adjusted to some extent by changing the air pressure, this correlation is relatively coarse.

[0010] This type of general-purpose removable screen is also prone to damage during storage. This is particularly problematic for ultra-thin "foil" screens used in high-precision applications that require submicron printing accuracy.

[0011] Another drawback of such removable screen printing assemblies is that some steps involved in using these assemblies are easily automated.

[0012] Therefore, there is still a need to improve high-precision screen printing. Summary of the Invention

[0013] According to a first aspect of the present invention, a method for constructing a printing screen assembly is provided, the method comprising:

[0014] A frame is provided, having an elongated first frame member and an elongated second frame member that is parallel to and fixed to the first frame member; and corresponding cantilevered first tensioning devices and cantilevered second tensioning devices extending from each frame member along its length.

[0015] Apply a pretension force to cause the first tensioning device to elastically deflect toward the second frame member and come into contact with the abutment arrangement of the first frame member;

[0016] While the first tensioning device is in contact with the first abutting arrangement structure, the printing screen is fastened to the attachment portion of the first tensioning device;

[0017] Fasten the printing screen to the attachment portion of the second tensioning device; and

[0018] Release the pre-tension force from the first tensioning device to apply tension to the printing screen.

[0019] The first tensioning device deflects until it contacts the first abutment arrangement, introducing a predictable amount of elastic potential energy, or "pre-tension," into the device. Upon release, the tensioning device deflects toward its undeflected "rest" position, keeping the printing screen taut between the first and second tensioning devices. The amount of tension applied to the printing screen is related to the amount of elastic potential energy introduced by deflecting the first tensioning device.

[0020] What will be understood is that the length of the corresponding frame member—along which the tensioning device extends—corresponds to the length of the edge of the tensioned printing screen in use.

[0021] The method may include: elastically deflecting a second tensioning device toward a first frame member and contacting a second abutting arrangement structure of the second frame member; securing a printing screen to an attachment portion of the second tensioning device while at least one second tensioning device is in contact with the second abutting arrangement structure; and releasing pretension from at least one second tensioning device.

[0022] The following steps can be performed in any suitable order: the step of deflecting the first tensioning device; the step of optionally deflecting the second tensioning device; the step of securing the printing screen to the attachment portion of the first tensioning device; and the step of securing the printing screen to the attachment portion of the second tensioning device.

[0023] In some implementations, the printing screen is attached when appropriate pre-tension has been applied (to one or both of the first and second tensioning devices).

[0024] The pretension force can also be released in any order.

[0025] The method may include tensioning the printing screen in a single direction (i.e., between the first frame member and the second frame member).

[0026] This method may include tensioning the printing screen in two directions.

[0027] Therefore, the frame may include: an elongated third frame member and an elongated fourth frame member parallel to the third frame member; and corresponding cantilevered third and fourth tensioning devices extending along the length of each of the third and fourth frame members; wherein the third and fourth frame members extend substantially between the first and second frame members and are orthogonal to the first and second frame members.

[0028] The method further includes applying a pre-tensioning force to elastically deflect the third tensioning device toward the fourth frame member and make it contact the third abutment arrangement structure of the third frame member; and

[0029] Apply a pretension force to cause the fourth tensioning device to elastically deflect toward the third frame member and contact the fourth abutment arrangement structure of the fourth frame member;

[0030] While applying pre-tension to the third and fourth tensioning devices, the printing screen is secured to the attachment portions of the third and fourth tensioning devices; and

[0031] Release the pre-tension force from the third tensioning device to apply tension to the printing screen.

[0032] The steps of deflecting the tensioning device / each tensioning device and securing the printing screen to the attachment portion of the tensioning device can be performed in any suitable order.

[0033] In some implementations, depending on the circumstances, the printing screen is attached after all the appropriate pretensions have been applied to the first tensioning device and optionally the second and / or third and / or fourth tensioning devices.

[0034] In some embodiments that include first to fourth frame members, the printing screen is attached to the attachment portions of the first and second tensioning devices after a pretension force has been applied to the first tensioning device and optionally the second tensioning device. The pretension force can then be released to tension the printing screen between the first and second tensioning devices. The method may include subsequently applying pretension forces to the third and fourth tensioning devices.

[0035] Each tensioning device includes at least one tensioning element. Each tensioning device may independently include two or more tensioning elements; for example, a series of tensioning elements along the respective frame members; or a single elongated tensioning element.

[0036] Each abutment arrangement may independently include two or more abutments, such as a series of abutments along the corresponding frame members; or a single elongated abutment.

[0037] The number of abutments and tensioning elements along the length of the frame member can be the same or different. For example, a given tensioning element can be deflected to contact more than one abutment, or more than one tensioning element can be deflected to contact a given abutment.

[0038] A pretension force can be applied to a first tensioning device using at least one first deflection element. The method may include moving at least one first deflection element from a first side of the first frame member (i.e., from a side farther from the second frame member than from the first frame member and therefore from the outside of the frame) toward the first frame member (and therefore also toward the second frame member).

[0039] A single deflector element or multiple deflector elements can be used to deflect a given tensioning device. The number of deflector elements can be the same as or different from the number of tensioning elements. One deflector element can be used to deflect more than one tensioning element, or more than one deflector element can be used to deflect tensioning elements.

[0040] The method may include applying a pre-tension force to the second tensioning device using at least one second deflection element. The method may include moving at least one second deflection element from a second side of the second frame member (i.e., from a side farther from the first frame member than the second frame member and therefore from the outside of the frame) toward the second frame member (and therefore also toward the second frame member).

[0041] The method may include using at least one third deflection element and optionally at least one fourth deflection element.

[0042] In some embodiments, where the frame includes a third frame member and a fourth frame member, the method may include rotating the frame such that at least one first deflection element and at least one second deflection element can be used to apply pretension to the third and fourth tensioning devices.

[0043] The movement of the deflecting element can be achieved in any suitable manner; for example, the deflecting element can be electromechanically actuated, pneumatically actuated, or hydraulically actuated.

[0044] The one or more deflection elements will typically move generally within the plane of the frame (e.g., parallel to the reference edge).

[0045] The deflecting element may be sized to extend through an opening in the finger guard. The end portion of the deflecting element may be sized to extend through an opening in the tensioning device. The deflecting element may include a tapered end portion and a protrusion or flange. The tapered end portion may facilitate alignment of the deflecting element with an opening in the tensioning device and, optionally, with a corresponding opening in an abutment arrangement. The protrusion or flange may be sized to engage with the tensioning device around the opening or to bridge across the opening.

[0046] Each tensioning device includes at least one tensioning element. Each tensioning element extends from a fixed end connected to a corresponding frame element to a free end. The attachment portion of each tensioning element may be located at or near the free end of each tensioning element.

[0047] The method may include pre-selecting a tension applied by at least one of a first tensioning device or a second tensioning device (and, if present, a third and / or a fourth tensioning device).

[0048] The tensioning device, or each tensioning device, may comprise, or be formed from, an elastic sheet material such as stainless steel. The tension applied by the tensioning device can be pre-selected by removing material from the elastic sheet material, machining the elastic sheet material, and / or etching it to selectively reduce the thickness of the elastic sheet material in one or more regions. The tension applied by the tensioning device can be pre-selected by means of the distance between the tensioning device in its "resting" position and the corresponding abutment arrangement structure.

[0049] The thickness of the sheet material can be selectively reduced to control bending characteristics. Alternatively or additionally, one or more slots, cuts, or openings can be cut into the sheet material, or one or more slots, cuts, or openings can be cut from the sheet material to control bending characteristics.

[0050] One or more slots or cuts can be cut into or from the sheet material to define more than two tensioning elements.

[0051] The method may include forming orifices, slits, or reduced-thickness regions in any suitable pattern; for example, along an edge or apex that bends during pre-tensioning; on or through the surface of a flexible region between the fixed and free ends. Alternatively or additionally, material may be removed between the fixed and free ends of the tensioning element to control how the tensioning element flexes.

[0052] In some embodiments, the opening may correspond to an opening or recess in a frame member (e.g., an abutment arrangement and / or a finger guard) to facilitate pretensioning using a deflection element, as discussed in further detail below.

[0053] This method may include precise processing of the elastic sheet material, such as laser processing or etching. Other machining or etching methods, such as CNC machining or plasma processing, may also be used.

[0054] In some embodiments, the method may include varying the tension applied by at least one of the tensioning devices along the length of the respective frame member.

[0055] Tension can be varied, for example, by providing increased tension in the middle of the printing screen. A taut printing screen will tend to sag with distance from the point where it is attached to the frame, typically with distance from the corners of the frame. This method allows for the application of greater tension where resistance to this sagging is needed.

[0056] Tension can be varied by changing the pattern machined and / or etched along the corresponding tensioning device. For example, more machining and / or etching can be performed on a portion of the tensioning device closer to the frame corner or on the tensioning element.

[0057] This pre-selection via machining and / or etching can be conveniently carried out during the manufacture of the corresponding tensioning device.

[0058] The frame members may include nonlinear or non-collinear abutments; and the tension can be changed by altering the amount by which the corresponding tensioning device deflects along the length of the frame member.

[0059] Tensioning elements can be formed from elastic sheet materials.

[0060] The term "formed from sheet material" in this context refers to manufacturing processes such as bending, rolling, stamping, and pressing. Manufacturing processes such as extrusion, molding, or casting are excluded. Tensioning elements, frame components, or other articles formed from sheet material will possess the characteristics of sheet material; for example, the material thickness of all parts of the device features penetrating the sheet material; and / or creases, bends, etc., which, if reversed, would produce a planar article. Devices formed from sheet material can also typically present or represent two-dimensional patterns or outlines on the sheet material.

[0061] Tensioning devices can be manufactured by bending elastic sheet materials, for example by roll forming, pressing, stamping, etc. The sheet material can be bent to form one or more attachment portions and / or one or more interlocking structures (discussed in further detail below).

[0062] The method may include, for example, forming the profile of a tensioning element on a sheet material by precision processing (machining, laser cutting, etc.) or stamping, and subsequently performing one or more steps of bending, rolling, stamping and pressing the sheet material to form the tensioning element.

[0063] The method may include forming multiple tensioning elements from a single sheet of material.

[0064] The method may include, for example, forming the outline of one or more of the tensioning elements by stamping or machining a “blank” from a single sheet material, and then performing one or more steps of bending, rolling, stamping and pressing the sheet material to form each tensioning element.

[0065] Sheet materials or tensioning elements can be machined and / or etched before bending.

[0066] The first, second, third, and / or fourth tensioning devices may be integrally formed with the corresponding frame members. In some embodiments, the method may include bending sheet material to form a frame member and tensioning devices extending from the frame member.

[0067] The method may include attaching a first tensioning device, a second tensioning device, a third tensioning device and / or a fourth tensioning device to the respective frame members.

[0068] Therefore, in a second aspect, the invention extends to a method of manufacturing a frame for a printing screen assembly, the method comprising:

[0069] An elongated first frame member and an elongated second frame member are provided; at least the first frame member has an abutment arrangement structure;

[0070] The first frame member is fixed in a parallel relationship with the second frame member, wherein the abutting arrangement structure is oriented away from the second frame member;

[0071] A first tensioning device and a second tensioning device are provided that can be elastically deflected, each tensioning device having an attachment arrangement structure configured for attachment to a printing screen.

[0072] The first tensioning device is attached to the first frame member, and the second tensioning device is attached to the second frame member;

[0073] Thus, each tensioning device extends in a cantilever relationship relative to the corresponding frame member, wherein the first tensioning device extends at a predetermined distance from the abutment arrangement of the first frame member.

[0074] The second frame member may include an abutment arrangement structure oriented away from the first frame member, and the method may include attaching a second tensioning device to a second tensioning element, whereby the second tensioning element extends at a predetermined distance from the abutment arrangement structure of the second frame member.

[0075] The method may include setting an elongated third frame member and an elongated fourth frame member, a third tensioning device and a fourth tensioning device, and attaching the tensioning devices to the corresponding frame members.

[0076] The method may also include direct or via corner components to frame members as disclosed herein.

[0077] By manufacturing the frame components and tensioning devices separately and attaching them in this manner, each can be optimized to meet specific requirements. For example, the frame components and tensioning devices may require different materials or different material thicknesses or properties. This construction method also facilitates the subsequent disassembly and reuse of at least the frame components.

[0078] The tensioning device can be attached to the frame member by any suitable method, such as welding, joining, fasteners (bolts, rivets, etc.), or by an interlocking arrangement, such as inserting a portion of the tensioning device into a slot or channel. The tensioning device can be attached to the frame member and held to it by friction. The tensioning device can be attached to the frame member and held to it by flexing, for example, a portion of the frame or a portion of the tensioning device.

[0079] The tensioning device can be removable or replaceable.

[0080] The interlocking arrangement structure may include a tensioning element interlocking structure, such as a lip or protrusion, located at or near the fixed end of the tensioning element, and a corresponding groove, channel, or recess in the frame member, wherein the groove, channel, or recess includes a frame member interlocking structure adapted to engage with the tensioning element interlocking structure.

[0081] A given tensioning device may include more than one tensioning element interlocking structure.

[0082] In embodiments where the tensioning device is attached to the frame member at least partially by means of friction, flexure, and / or interlocking arrangements, the attachment between the tensioning device and the frame member can be configured to increase engagement between the frame member and the tensioning device when the tensioning device is elastically deflected. Therefore, the method can include increasing engagement between at least one tensioning device (e.g., an interlocking structure of the tensioning device's elements) and at least one frame member (e.g., an interlocking structure or groove / channel of the frame member) by elastically deforming a first, second, third, and / or fourth tensioning device.

[0083] The method may include attaching a first tensioning device, a second tensioning device, a third tensioning device, and / or a fourth tensioning device to a respective frame member by inserting a portion of at least one of the tensioning devices into a slot, channel, or recess defined by the respective frame member.

[0084] A portion of the tensioning device, such as a tensioning element interlocking structure, can be inserted into the slot, channel, or recess by moving the tensioning device generally toward the frame member. Inserting a portion of the tensioning device into the slot / channel / recess may include elastically deforming the tensioning device, such as elastically deforming the interlocking structure of the tensioning device. This elastic deformation can be mitigated or eliminated when at least one tensioning device is fully inserted. The slot may taper in width to facilitate this insertion.

[0085] A portion of a tensioning device can be inserted into a slot, channel, or recess by moving at least one tensioning device generally along a frame member, for example, along the slot / channel / recess. The method may include inserting a portion of at least one of the tensioning devices from one end of an elongated frame member.

[0086] The tensioning device can be inserted into the slot, channel, or recess approximately perpendicular to the length of the slot, channel, or recess.

[0087] Each frame element may include a single slot, channel, or recess, or multiple slots, channels, or recesses.

[0088] As described above, each frame member may include an abutment arrangement structure, which includes a single abutment or more than one abutment.

[0089] The abutment arrangement structure may include a linear abutment portion extending along the length of the frame member. The abutment arrangement structure may also include a collinear abutment portion extending along the length of the frame member. Therefore, the corresponding tensioning device can elastically deflect along the length of the frame member by the same amount during use.

[0090] In some embodiments, the abutment structure includes a nonlinear abutment portion or a non-collinear abutment portion, allowing the tensioning device to deflect to different degrees along the length of the frame member.

[0091] The terms linear and collinear refer to the following direction: the direction is along the length of the corresponding elongated frame member, and is therefore parallel to the plane of the printing screen of the resulting screen assembly and usually parallel to the edge of the printing screen.

[0092] The method may include casting, machining, and / or extruding each frame member. In some embodiments, the frame members are formed from extruded plastic material or extruded metal material, such as aluminum.

[0093] The method may include forming each frame member from sheet material. The method may include bending the sheet material and / or welding the sheet material to form the frame member, such as a frame member having a generally hollow structure.

[0094] The method may include, for example, forming the outline of a frame member on a sheet of material by precision processing (machining, laser cutting, etc.) or stamping, and subsequently performing one or more steps of bending, rolling, stamping and pressing the sheet material to form the frame member.

[0095] This method may include forming multiple frame members from a single sheet of material.

[0096] The method may include, for example, forming the outline of one or more of the frame members by stamping or machining a “blank” from a single sheet of material, and then performing one or more steps of bending, rolling, stamping and pressing the sheet material to form each frame member.

[0097] Sheet material or blanks can be machined and / or etched before bending. For example, to create one or more weak point lines to facilitate bending, machining can be performed before bending.

[0098] As disclosed herein, frame members may include one or more openings for inserting deflection elements, or for inserting or removing tensioning devices. In some embodiments, the method may include, for example, forming one or more openings, or an array of openings, by machining or stamping a sheet material or blank.

[0099] The method may include a tensioning device integrally formed with the frame members.

[0100] This method may include constructing the framework.

[0101] Constructing the frame may include fixing the first frame member and the second frame member parallel to each other and spaced apart.

[0102] The first frame member and the second frame member can each be fixed to the base frame.

[0103] The first frame member and the second frame member can each be fixed to the middle frame member at approximately their ends.

[0104] In some embodiments, constructing the frame may include fixing a third frame member and a fourth frame member parallel to each other and spaced apart, and orthogonal to the first frame member and the second frame member.

[0105] The first frame member, the second frame member, the third frame member, and the fourth frame member can each be fixed to the base frame.

[0106] The first and second frame members can be directly fixed to the third and fourth frame members or fixed to the third and fourth frame members via corner connectors.

[0107] Frame members can be joined or welded to each other, optionally via corner connectors.

[0108] In some implementations, one or both ends of each frame member may be mitered, and the mitered ends may be joined, welded, or otherwise connected together.

[0109] The steps of constructing the frame and, in embodiments having a tensioning device that is not integrally formed with the frame members, attaching the tensioning device to the respective frame members, can be performed in any order.

[0110] In some embodiments, for example, each tensioning device is attached to each frame member by sliding along a channel or groove defined by the respective frame member, one or both ends of which may be blocked when the frame has been constructed (in order to at least partially retain the tensioning device). In such embodiments, the tensioning device may be attached to the respective frame member before the frame member is secured in place, so as to block the channel or groove.

[0111] In some implementations, the frame or each frame member includes one or more access openings to facilitate the insertion or removal of a tensioning device from the frame.

[0112] Each frame member may include a reference edge that defines a horizontal line for the edge of the printing screen assembly during use.

[0113] The reference edges of the first and second frame members (and, where applicable, the third and fourth frame members) may be coplanar.

[0114] Each reference edge can be a surface, a lip, or a ridge.

[0115] In the resting position, the attachment portion of the tensioning device can be located outside the plane of the reference edge of the corresponding frame member. Elastic deflection of the tensioning device can cause the tensioning element to pivot substantially so that the attachment portion enters, approaches, or passes through and across the plane of the reference edge.

[0116] The method may include contacting the printing screen with the reference edge / each reference edge, and then fastening the printing screen. The method may also include contacting the printing screen with the reference edge / each reference edge, and bending a portion of the printing screen extending beyond the reference edge to contact the attachment portion / each attachment portion.

[0117] In some implementations, the method may include releasing the pretension force to bring the printing screen into contact with a reference edge.

[0118] This method may include forming a printed pattern on a printing screen.

[0119] In some embodiments, the screen is a mesh emulsion screen, and the pattern is produced by applying a layer of photosensitive polymer precursor solution or suspension to the mesh and selectively curing the polymer precursor to form a polymer mask, as is known to those skilled in the art.

[0120] In some embodiments, the screen is formed of a sheet material (such as a polymer sheet or a metal sheet such as stainless steel), and the method may include precisely cutting the printed pattern. Precise cutting may include laser cutting. Other precise cutting methods may be used (such as water jetting, plasma cutting, etc.).

[0121] The method may include securing the printing screen and then producing a printed pattern, or more typically, producing a printed pattern and then securing the printing screen.

[0122] The attachments for securing the printing screen to the first tensioning device and to the second tensioning device (and optionally the third and fourth tensioning devices) may include welding, bonding with adhesive, or securing the printing screen to each attachment via hooks. Securing the printing screen may include riveting.

[0123] Welding can include laser welding. Conveniently, where the laser is used to create the printed pattern, the same laser can be used to weld the printed screen to the attachment portion.

[0124] Any suitable soldering pattern can be used, including a single line, multiple lines (continuous or parallel), or a series of solder joints.

[0125] The printing screen may include hook-like portions extending along a length substantially corresponding to the length along which each tensioning device extends. The method may include hooking each hook-like portion to a corresponding attachment portion of each tensioning device.

[0126] In other words, the printing screen may include a first hook-shaped portion and a second hook-shaped portion, as well as optional third and fourth hook-shaped portions. It will be understood that in embodiments where the hook-shaped portions are integral with or attached to the screen before it is secured to the tensioning device, the hook-shaped portions will be spaced apart when a pre-tensioning force is applied to allow opposing hook-shaped portions to be secured; however, when the corresponding opposing tensioning devices (the first and second tensioning devices, and optionally the third and fourth tensioning devices) are in their rest positions, the opposing hook-shaped portions will not be secured.

[0127] The hook-shaped portion can be integrated with the printing screen. The hook-shaped portion can be formed, for example, by bending along the edge of the printing screen sheet material.

[0128] The method may include attaching hook-shaped portions to a printing screen. Individual hook-shaped portions may be formed of a different material or a material of different thickness / strength than the printing screen, which can facilitate, for example, securing the screen to the attachment portion when using a very thin printing screen.

[0129] The hook-shaped parts can be joined by any suitable method, including joining, welding, riveting, etc.

[0130] Conveniently, in embodiments where laser is used to generate printed patterns, and / or in embodiments where laser is used in other parts of the method (e.g., laser welding of attachment portions to the screen, laser processing of tensioning devices, connection of frame members via laser welding), the same laser can be used to laser weld the hook portion to the printing screen.

[0131] In some implementations, both the wire mesh and the hook portion can be welded or bonded to the attachment portion to provide additional strength.

[0132] The method may include constructing a printing screen assembly for a generally square or rectangular printing screen.

[0133] This method may include optionally cutting the printing screen to a specific size in situ on a frame. For example, the printing screen may be placed on a large sheet or roll of material or mesh and cut to a specific size.

[0134] In embodiments that include laser welding and / or cutting (or another form of cutting or welding), the method may include welding using the same equipment, producing a printed pattern, and / or cutting the printing screen to a certain size.

[0135] According to a third aspect of the present invention, a method for manufacturing a frame for a printing screen assembly is provided, the method comprising:

[0136] An elongated first frame member and an elongated second frame member parallel to and fixed to the first frame member are provided; each frame member has a corresponding cantilevered first tensioning device and tensioning device extending from each frame member along its length.

[0137] The method includes forming a first tensioning device and a second tensioning device from an elastic sheet material, and pre-selecting the elasticity of the first tensioning device and / or the second tensioning device by removing material from the elastic sheet material, machining and / or etching the elastic sheet material (in order to pre-select the tension applied when tensioning the printing screen in use, as disclosed herein).

[0138] The invention is further extended in a fourth aspect to a method of constructing a printing screen assembly, the method comprising: manufacturing a frame by the method of the third aspect (or setting a frame according to the seventh aspect discussed below); applying a pretension force to elastically deflect a first tensioning device toward a second frame member (and optionally elastically deflect a second tensioning device toward the first frame member);

[0139] While pre-tensioning the first tensioning device and the optional second tensioning device, the printing screen is fastened to the attachment portion of the first tensioning device;

[0140] Fasten the printing screen to the attachment portion of the second tensioning device; and

[0141] Release the pretension force from the first tensioning device (and from the second device if pretensioned) to apply tension to the printing screen.

[0142] It will be understood that the frame may include third and fourth frame members and corresponding tensioning elements.

[0143] This method may include selectively reducing the thickness of the elastic sheet material.

[0144] The method may include cutting one or more slots, cuts or openings in or from a sheet material.

[0145] This method may include precisely processing the elastic sheet material, such as laser processing or etching, to selectively reduce the thickness or cut out grooves, notches, or holes.

[0146] In some implementations, the method may include varying the elasticity of the first tensioning device and / or the second tensioning device along the length of the respective frame member.

[0147] Tensioning devices can be manufactured by bending elastic sheet materials, for example by roll forming, pressing, stamping, etc.

[0148] Sheet materials can be machined and / or etched before bending.

[0149] The method may include forming at least one first tensioning device and / or a second tensioning device, and then attaching the at least one first tensioning device and / or the second tensioning device to the respective frame member.

[0150] The method may include providing a tensioning element interlocking structure for each of the tensioning devices, providing a corresponding interlocking structure for each frame member; and attaching each tensioning element interlocking structure to the corresponding frame member interlocking structure.

[0151] The method may include attaching a first tensioning device and / or a second tensioning device to a respective frame member by inserting a portion of the tensioning device, such as a portion extending from the edge of the tensioning device or a tensioning element interlocking structure, into a slot, channel, or recess defined by the frame member.

[0152] Each tensioning element interlocking structure can be inserted into the slot, channel, or recess by moving at least one tensioning element substantially along the frame member, for example, from one end of an elongated frame member.

[0153] Each frame member may include a single slot, channel, or recess, or multiple slots, channels, or recesses, which are sized to receive part of a tensioning device, such as an interlocking structure of the tensioning device.

[0154] Each frame member may include an abutment arrangement extending along the length of the frame member. The abutment arrangement may be configured relative to at least one frame member interlocking structure such that when the tensioning element interlocking structure of the tensioning device is attached to the abutment arrangement, a predictable pre-tension force in use can be applied to the tensioning device by elastically deflecting it into contact with the abutment arrangement.

[0155] This method may include constructing the framework.

[0156] Constructing the frame may include fixing the first frame member and the second frame member parallel to each other and spaced apart.

[0157] The frame may include a third elongated frame member and a fourth elongated frame member, as well as corresponding third and fourth tensioning devices. The steps disclosed herein regarding the first and second elongated frame members, and the first and second tensioning devices, apply to the third and fourth frame members, and the third and fourth tensioning devices.

[0158] The steps can be performed in any suitable order.

[0159] The method may include manufacturing frame members. Each frame member may be manufactured by machining and / or extrusion. In some embodiments, the frame elements are formed from extruded plastic or extruded metal materials, such as aluminum.

[0160] The method may include extruding each frame member to form an elongated frame member having at least one abutment arrangement structure and at least one frame member interlocking structure.

[0161] Each frame component can be formed from sheet materials such as steel through rolling, pressing, folding, etc.

[0162] Other optional steps of the method in the first to fourth aspects correspond to those steps disclosed in any other aspect of the first to fourth aspects of the invention.

[0163] In a fifth aspect, the invention extends to a printing screen assembly comprising:

[0164] A frame having an elongated first frame member and an elongated second frame member that is parallel to and fixed to the first frame member;

[0165] A cantilevered first tensioning device and a cantilevered second tensioning device extend along the length of each respective frame member; each tensioning device includes an attachment portion located at or near the free end of the tensioning device along the length;

[0166] The first frame member includes a first abutting arrangement structure; the first tensioning device is operable to elastically deflect toward the second frame member and contact the first abutting arrangement structure; and

[0167] A printing screen is attached to an attachment portion of a first tensioning device and an attachment portion of a second tensioning device and is kept taut between the two attachment portions.

[0168] When the first tensioning device deflects into contact with the abutment arrangement structure as the screen is attached, the tension in the printing screen is determined by the amount of pretension applied to the first tensioning device.

[0169] The length of the corresponding frame component—along which the tensioning device extends—corresponds to the length of the edge of the tensioned printing screen.

[0170] The second frame member may include a second abutment arrangement structure; wherein the second tensioning device is operable to elastically deflect toward the first frame member and contact the second abutment arrangement structure.

[0171] The frame may include: an elongated third frame member and an elongated fourth frame member parallel to the third frame member; and corresponding cantilevered third and fourth tensioning devices extending along the length of the third frame member and other frame members; each tensioning device includes an attachment portion located at or near the free end of the tensioning device along the length.

[0172] Among them, the third frame member and the fourth frame member extend generally between the first frame member and the second frame member and are orthogonal to the first frame member and the second frame member;

[0173] The third frame member includes a third abutment arrangement structure; the third tensioning device is operable to elastically deflect toward another frame member and contact the third abutment arrangement structure; and

[0174] The fourth frame member includes a fourth abutment arrangement structure; wherein the fourth tensioning device is operable to elastically deflect toward the third frame member and contact the fourth abutment arrangement structure;

[0175] The printing screen is attached to the attachment portion of the third tensioning device and the attachment portion of the fourth tensioning device, and is kept taut between the two attachment portions.

[0176] Printing screens can be made of sheet materials, such as stainless steel.

[0177] Printed screens can be welded (e.g., laser welded) or bonded or riveted to the attachment.

[0178] The printing screen can be fastened to each of the attachment portions via hooks.

[0179] The hook-shaped portion can be integrated with the printing screen, for example, by bending along the edge of the printing screen sheet material.

[0180] The hook-shaped parts can be joined, welded (e.g., laser welded), riveted, etc., to the printing screen.

[0181] In a sixth aspect of the invention, a frame for a printing screen assembly is provided, the frame comprising:

[0182] An elongated first frame member and an elongated second frame member that is parallel to and fixed to the first frame member;

[0183] A cantilevered first tensioning device and a cantilevered second tensioning device extend along the length of each respective frame member; each tensioning device includes an attachment portion located along the length at or near the free end of the tensioning device for attachment to the printing screen.

[0184] The first frame member includes a first abutting arrangement structure; wherein the first tensioning device is operable to elastically deflect toward the second frame member and contact the first abutting arrangement structure.

[0185] The second frame member may include a second abutment arrangement structure; wherein the second tensioning device is operable to elastically deflect toward the first frame member and contact the second abutment arrangement structure.

[0186] The frame may include: an elongated third frame member and an elongated fourth frame member parallel to the third frame member; and corresponding cantilevered third and fourth tensioning devices extending along the length of the third frame member and other frame members; each tensioning device includes an attachment portion located at or near the free end of the tensioning device along the length.

[0187] Among them, the third frame member and the fourth frame member extend generally between the first frame member and the second frame member and are orthogonal to the first frame member and the second frame member;

[0188] The third frame member includes a third abutment arrangement structure; the third tensioning device is operable to elastically deflect toward another frame member and contact the third abutment arrangement structure; and

[0189] The fourth frame member includes a fourth abutment arrangement structure; wherein the fourth tensioning device is operable to elastically deflect toward the third frame member and contact the fourth abutment arrangement structure.

[0190] Each tensioning device includes at least one tensioning element that extends from a fixed end connected to a corresponding frame element to a free end.

[0191] The attachment portion of each tensioning element may be located at or near the free end of each tensioning element.

[0192] Each attachment portion can be configured to attach to the printing screen when the tensioning device deflects into contact with the corresponding abutment arrangement. It will be understood that each tensioning element will tend to pivot about its fixed end upon deflection, allowing the orientation of the attachment portion to change. Therefore, when the corresponding tensioning device deflects into contact with the abutment arrangement, the attachment portion can be optimally oriented for attachment to the printing screen.

[0193] The tensioning device, or each tensioning device, may comprise, or be formed of, an elastic sheet material such as stainless steel. The tension applied by at least one of the first and second tensioning devices (and, if present, a third and a fourth tensioning device) may be independently pre-selected by: selecting the material properties of the sheet material (e.g., material thickness, elasticity, etc.), removing material from the elastic sheet material, or machining and / or etching the elastic sheet material.

[0194] Therefore, at least one of the tensioning devices can have a variable thickness. The characteristics of the sheet material described below will be apparent to those skilled in the art: the sheet material has been machined (e.g., CNC machining) or etched (e.g., using a laser) to selectively reduce the thickness in one or more of its regions.

[0195] Alternatively or additionally, one or more slots, cuts or openings may be cut into or from the sheet material to control bending characteristics.

[0196] One or more slots or cuts can be cut into or from the sheet material to define more than two tensioning elements.

[0197] Grooves, cuts, openings, and / or machined or etched patterns can be varied along the length of the tensioning device; for example, to provide increased tension in the middle of the printing screen.

[0198] The tensioning device can be attached to the corresponding frame member, or optionally removably attached to the corresponding frame member.

[0199] In some embodiments, as disclosed herein, the tensioning device is attached to the frame member by an interlocking arrangement and / or by insertion into a slot or channel.

[0200] The interlocking arrangement structure may include a tensioning element interlocking structure, such as a lip or protrusion, located at or near the fixed end of the tensioning element, and a corresponding groove, channel, or recess in the frame member, wherein the groove, channel, or recess includes a frame member interlocking structure adapted to engage with the tensioning element interlocking structure.

[0201] Each frame component may include an elongated slot or channel for receiving a portion of the tensioning device, such as a tensioning element interlocking structure.

[0202] Each frame member may include an abutment arrangement structure, which includes a single abutment or more than one abutment.

[0203] The abutment arrangement structure may include a linear abutment extending along the length of the frame member.

[0204] Each frame component can be cast, machined, or extruded into a single piece. Each frame component can be formed from sheet material.

[0205] Each frame member may include a reference edge that defines a horizontal line for the edge of the printed screen of the screen assembly during use.

[0206] The reference edges of the first and second frame members (and, where applicable, the third and fourth frame members) may be coplanar.

[0207] The frame may include frame members fixed to each other. For example, frame members may be attached to a base frame, or connected by corner connectors, or frame members may be directly connected to each other around the frame; for example, via miter joints of the frame members.

[0208] In the static position and in some embodiments, when attached to a printing screen, the attachment portion of each tensioning device may be located outside the plane of the reference edge of the respective frame member.

[0209] The frame may also include one or more external safety guards or be able to connect to one or more external safety guards, which are often referred to as finger guards.

[0210] For some applications, the printing screen may be very thin and fragile. Furthermore, the joint between the printing screen and the attachment points may be relatively weak, and / or the screen may be easily damaged by accidental movement of the tensioning device. Sharp edges or other hazards that could cut or pinch the user's hands may also exist at the attachment points and other areas of the tensioning device and / or frame.

[0211] The external safety guard or finger guard, or each external safety guard or finger guard, can provide protection for the attached portion.

[0212] In some implementations, the external safety guards, or each external safety guard, may be attached after the frame has been secured or after the tensioning device has been attached to the frame.

[0213] The external safety guards, or each external safety guard, can be attached in any suitable manner, such as by clipping onto or to the frame elements. The external safety guards can take the form of mesh or sheet material (e.g., folded sheet material).

[0214] The external safety guard or finger guard, or each external safety guard or finger guard, may be formed from a sheet of material. Each external safety guard may be integrally formed with other parts of the frame member; it may be formed from the same sheet material or blank.

[0215] The external safety guard, or each external safety guard, may be provided with one or more openings. These openings can provide an inlet for the deflection element to contact the corresponding tensioning device.

[0216] In a seventh aspect, the invention extends to a frame for a printing screen assembly, the frame comprising: an elongated first frame member and an elongated second frame member parallel to and fixed to the first frame member; each frame member having a corresponding cantilevered first tensioning device and tensioning device extending from each frame member along its length.

[0217] The first tensioning device and the second tensioning device are formed of elastic sheet material, and the elasticity of the first tensioning device and / or the elasticity of the second tensioning device are pre-selected by removing material from the elastic sheet material, machining and / or etching the elastic sheet material (in order to pre-select the tension applied when the printing screen is tensioned in use, as disclosed herein).

[0218] The invention extends in an eighth aspect to a printing screen assembly comprising the frame of the seventh aspect; and

[0219] A printing screen is attached to an attachment portion of a first tensioning device and an attachment portion of a second tensioning device and is kept taut between the two attachment portions.

[0220] When it is mentioned that one structural feature is in a fixed relationship with another structural feature, it means that the two structural features are rigidly connected, for example, directly or indirectly, through one or more other structural features.

[0221] The term “setup” includes only acquiring or having, but may also include making or manufacturing.

[0222] The term elasticity describes the property of a material or structure to return to its original shape after deformation (including deflection, bending, etc.). Elastically deformable materials or structures can be deformed elastically.

[0223] When referring to a structural feature being integrally formed with another structural feature, it means that the structural feature is formed from a single piece of material, such as a sheet or block of material. Integral formation in this document does not include structural features that were initially separated and then permanently or temporarily joined together.

[0224] Terms such as up, down, above, and below refer only to the orientation shown in the figure, or, where applicable, to the orientation when using the device, and are not intended to be limiting.

[0225] Other preferred and optional features of each aspect of the invention correspond to preferred and optional features of any other aspect of the invention. In particular, where the methods disclosed herein involve structural features, it will be understood that the devices disclosed herein may include any such structural features. Furthermore, where the function or operation of the device is disclosed, it will be understood that the method may include such operational or functional steps. Attached Figure Description

[0226] A non-limiting exemplary embodiment will now be described with reference to the following accompanying drawings, in which:

[0227] Figure 1 A perspective view of an embodiment of a frame for a printing screen assembly is shown;

[0228] Figure 2 It shows crossing Figure 1 Cross-sectional view of the frame components of the frame;

[0229] Figure 3 A perspective view of the frame member and the deflection element adjacent to the tensioning device of the frame member is shown.

[0230] Figure 4 A cross-sectional view of a frame member and a deflection element adjacent to the tensioning device of the frame member is shown.

[0231] Figure 5 A perspective view of the frame components and deflection elements is shown, wherein the tensioning device contacts the abutment and the printing screen during attachment to the frame;

[0232] Figure 6 A cross-sectional view of the frame members and deflection elements is shown, wherein the tensioning device contacts the abutment and the printed screen during attachment to the frame;

[0233] Figure 7 It is a cross-sectional view of the frame member passing through the printing screen assembly;

[0234] Figure 8 It is a 3D view of the printing screen assembly;

[0235] Figure 9 A cross-sectional view of the frame member and deflection element of the printing screen assembly is shown, wherein the tensioning device contacts the abutment portion of the frame member, and the printing screen has a hook-shaped portion that attaches to the attachment portion of the tensioning device.

[0236] Figure 10 This illustrates the process of laser welding printed screens to the attachment portion. Figure 9 A cross-sectional view of the frame components of the printing screen assembly;

[0237] Figure 11 A cross-sectional view of the frame member and deflection element of the printing screen assembly is shown, wherein the tensioning device contacts the abutment portion of the frame member, the elongated hook-shaped portion hooks around the attachment portion of the tensioning device, and the printing screen is positioned to be attached to the attachment portion.

[0238] Figure 12 This illustrates the process of laser welding printed screens to the hook-shaped and attachment portions. Figure 11 A cross-sectional view of the frame components of the printing screen assembly;

[0239] Figure 13 A cross-sectional view of an alternative embodiment of the frame member is shown;

[0240] Figure 14 A plan view of a tensioning device with an array of cuts is shown during the manufacture of the tensioning device;

[0241] Figure 15 and Figure 16 The plan view and cross-sectional view of the tensioning device with a region of reduced material thickness during the manufacture of the tensioning device are shown;

[0242] Figure 17 A plan view of a tensioning device with multiple tensioning elements having cutouts and reduced thickness areas is shown, which provide a pre-selected and variable tension along the length of the tensioning device during its manufacture;

[0243] Figure 18 This is another implementation of a frame for printing screen assemblies;

[0244] Figure 19 It includes Figure 18 Another embodiment of the printing screen assembly of the frame shown;

[0245] Figure 20 This is a cross-sectional view along another embodiment of the frame member;

[0246] Figure 21 and Figure 22 yes Figure 21 A cross-sectional side view of a frame member, illustrating the attachment of the tensioning device to the frame member;

[0247] Figure 23 This is a perspective view of an embodiment of a frame for a printing screen assembly;

[0248] Figure 24 and Figure 25 yes Figure 23 Detailed perspective and side view of the frame; and

[0249] Figures 26 to 28 yes Figure 20 A cross-sectional side view of the frame member, illustrating the deflection and pretensioning of the tensioning device. Detailed Implementation

[0250] Figure 1 A frame 10 for a printing screen assembly is shown. The frame includes an elongated first frame member 20 and an elongated second frame member 30. The frame members 20 and 30 are held in a fixed relationship to each other by side members 12. The frame members 20 and 30 are parallel to each other.

[0251] Figure 2 A cross-sectional view of the first frame member 20 is shown in more detail. The upper end portion 22 of the frame member 20 defines a reference edge 22a along its upper side (in the orientation shown in the figures) to define the horizontal line of the printing screen in use. The reference edge 22a of the first frame member 20 and the reference edge 32a of the second frame member 30 are coplanar.

[0252] In an alternative embodiment, the frame members do not include different reference edge structures 22a, 32a, and the upper ends 22, 32 serve as reference edges.

[0253] Facing outwards (farthest from the second frame member 30), the frame member 20 defines a channel or groove 24 in which a tensioning device in the form of a single elongated tensioning element 26 is received. The tensioning device is formed of spring steel, and the method of manufacturing the tensioning device will be discussed in further detail below.

[0254] The tensioning element 26 is held by an interlocking arrangement, which takes the form of a lip 26a formed along the lower edge of the tensioning element 26 and a corresponding bend 24a located in the groove 24. The tensioning element interlocking structure (lip 26a) and the frame member interlocking structure (bend 24a) engage with each other to hold the tensioning device to the frame member 20.

[0255] The tensioning element 26 is inserted into the channel from the end 24c of the channel generally along the length L of the frame member 20. In an alternative embodiment (not shown), the tensioning device can be inserted into the channel from the upper opening of the slot 24b. This alternative attachment method may require deformation of the tensioning element interlocking structure during insertion.

[0256] The attachment portion 26b of the tensioning element 26 is formed at the upper end of the tensioning element 26 as a platform or protrusion for attaching the printing screen. Therefore, the tensioning element is cantilevered and extends from the fixed end engaged by the interlocking structures 24a, 26a to the free end including the attachment portion 26a.

[0257] The frame member 20 also includes an abutment arrangement in the form of an elongated abutment portion 28 extending upward from the groove 24. The abutment portion 28 extends along the length of the frame member 20 and is profiled and positioned to contact the tensioning element 26 between the fixed end and the free end when the tensioning element is elastically deflected as discussed below.

[0258] exist Figure 2 In the “rest” position shown, the free end 26b of the tensioning element 26 is spaced apart from the abutment portion 28.

[0259] Reference Figure 3 , Figure 5 and Figure 8 The schematic perspective diagram shown is as follows: Figure 4 , Figure 6 and Figure 7 The schematic cross-sectional view shown illustrates the construction of the screen assembly 70 as follows.

[0260] In the illustrated embodiment, by deflection element 29 ( Figure 3 and Figure 4 A pre-tension force is applied to the tensioning device 26. The deflecting element 29 has a surface 29a, the profile of which has substantially the same curvature and orientation as the abutment portion 28. The deflecting member moves along direction X from the outside of the frame toward the opposite end of the frame, thereby deflecting the tensioning element 26 toward the second frame member (i.e., inward) and into contact with the abutment portion 28. Figure 5 and Figure 6 It should be understood that, in the example shown, the corresponding deflection element moves in the opposite direction -X from near the second frame member 30 to deflect the tensioning device 36 inward toward the first frame member 20.

[0261] Simultaneously, in this position, the printing screen 60 is positioned above the frame 10 and attached along the attachment portions 26b and 36b using laser welding via the laser processing head 50. Spot welding or wire welding can be used. The attachment portions 26b and 36b can be substantially coplanar with the reference edges 22a and 32a, slightly offset from the plane of the reference edges 22a and 32a (located below the plane along the indicated orientation), allowing the flatness of the printing screen to be precisely defined.

[0262] The deflection element 29 is then removed to release the pretension force, thereby tensioning the frame between the first tensioning element 26 and the second tensioning element 36. Figure 8 The image shows the completed printing screen assembly 70.

[0263] When the pretension is released, the tensioning element can spring back to its resting position to some extent away from the contact point. The degree of this springback can vary depending on the material of the printing screen. For example, while stainless steel screens will exhibit minimal springback, a greater degree of springback can be observed with plastic sheets or mesh printing screens.

[0264] This method is particularly easy to automate steps such as moving the deflection element to pre-tension the tensioning element, positioning and attaching the printing screen.

[0265] Printed patterns can be set on a printing screen using conventional methods such as laser cutting and emulsification. When using laser processing to create the printed pattern, the same laser processing head 50 can be used (before or after attachment to the frame).

[0266] The frame can be optionally cut to size in situ (e.g., from a larger sheet or roll), or it can be set in a pre-cut form.

[0267] Figure 9 Another embodiment of the printing screen 62 is shown, which has been rolled to produce hook-shaped edges 62a. The screen 62 is attached to the frame by hooking the hook-shaped edges 62a over the attachment portion 26b. The attachment portion is further pushed into the hook-shaped edges by the elastic bias of the tensioning element 26 toward its rest position.

[0268] To provide additional strength to the attachment (as may be necessary for particularly high-tension wire mesh), welding (or other methods such as joining, riveting, etc.) can be used along the length of the attachment, while applying pretension between the hook-shaped edge 62a and the attachment, such as... Figure 10 As shown in the image.

[0269] Figure 11 and Figure 12 An alternative method for attaching the printing screen 62' to the attachment portion 26b is shown. A separate, elongated hook-shaped portion 62b is positioned above the attachment portion 26b at each end of the frame (or along each side), and the screen 62' is positioned above the hook-shaped portion 62b. The hook-shaped portion, the screen, and the attachment portion are then laser-welded together.

[0270] The thickness of the material in the hook-shaped section, or actually the material itself, can be selected independently of the screen. This can be particularly advantageous for, for example, very thin printing screens.

[0271] In another embodiment, the hook-shaped portion can be attached to the printing screen before it is attached to the frame. For example, when using a mesh screen, the hook-shaped portion can be welded or otherwise joined, and the printing screen (together with the hook-shaped portion) is attached to the frame.

[0272] Figure 13 A cross-sectional view of another embodiment of the frame member 80 is shown. The frame member 80 is formed by pressing or rolling a sheet material such as stainless steel and has a generally hollow box-shaped cross-section construction defining an elongated orifice 84. The edge of the orifice defined by the sheet material serves as an interlocking structure 84a for engagement with the lip 26a of the tensioning element 26. The surface 88 extending upward from the orifice 84 serves as an abutment in use. The upper vertex 82 defines a reference edge. As the tensioning element 26 deflects to contact the abutment 88, the interlocking structures 26a, 84a are further pushed in to engage with each other.

[0273] In another embodiment (not shown), the frame and tensioning element are formed together from sheet material, or the tensioning element can be welded, riveted or bolted to the frame members.

[0274] Those skilled in the art will understand that the frame members (and side members) can be connected together in a variety of ways to be fixed to each other, such as by direct connection as shown in the figure, or by connection via corner members, or by connection via a base frame that defines the perimeter of the frame, to which all members are connected.

[0275] It will also be understood that while tensioning devices comprising a single frame element for each frame member 20, 30, 80 are shown, in alternative embodiments, more than one tensioning element may be included, for example, by cutting grooves or fine pleats along the edge of the sheet material. In other embodiments, the tensioning elements may even be completely separable from each other.

[0276] The frame can be assembled in the manner disclosed herein, including by pre-selecting the elasticity of the tensioning device to form the frame.

[0277] The elasticity of the tensioning device can be pre-selected by selectively removing material from the sheet material used to manufacture the tensioning element. In one example, such as... Figure 14 As shown, in order to selectively reduce the amount of pretension applied in the use of a given frame member, such as frame members 20, 3; the pattern of opening 91 is laser-cut into sheet material 90, as... Figure 14 As shown in the diagram. The sheet material is then folded or pressed along lines 94 and 96 to form the attachment portion 96b and the lip 96a, respectively.

[0278] Figure 15 Another example is shown, in which region 113 of sheet material 110 is selectively thinned by laser processing (see [reference]). Figure 16 Along the cross section of AA, in order to selectively reduce the elasticity of the resulting tensioning element. Alternatively, CNC machining or other machining methods can be used. The sheet material is then folded along lines 114 and 116 to form attachment portion 116b and lip 116a, respectively.

[0279] In alternative implementations, other patterns or combinations of reduced thickness and slits can be used. The amount of material removed can also be varied along the length of the tensioning device, for example, as... Figure 17 As shown, both a notch 121 and laser etching 123 are employed, and a groove 125 is cut through to the edge of the sheet material above the fold line 126. The resulting tensioning device 120 includes a single interlocking structure 126a and a plurality of tensioning elements 126 and attachment portions 126b along opposite edges; the pretension applied to the tensioning elements also varies along the length of the tensioning elements during use.

[0280] Figure 18 Another embodiment of frame 210 is shown, and Figure 19 An embodiment of the printing screen assembly 270 is shown, wherein the printing screen 260 is fastened to the frame 210. Similar reference numerals are added to the frame 10 and assembly 70 to provide the same features.

[0281] Frame 210 and assembly 270 are similar to frames 10 and assembly 70 and include a first frame member 220 and a second frame member 230, each frame member having an elongated tensioning element 226, 236 extending along its length from each frame member. Furthermore, frames 210 and assembly 270 include a third frame member 240 and a fourth frame member 250, each including a corresponding third tensioning element 246 and a fourth tensioning element 256 extending along its length from each frame member. The third frame member 240 and the fourth frame member 250 are parallel to each other and orthogonal to the first frame member 220 and the second frame member 230. Frame members 220, 230, 240, and 250 are connected to each other, and their reference edges 222a, 232a, 242a, and 252a are coplanar.

[0282] To secure the wire mesh 260 to the attachment portions 226b, 236b, 246b, and 256b, the tensioning elements 226, 236, 246, and 256 are deflected inward to contact the corresponding abutments, and when the tensioning elements are in this position, the wire mesh is welded to the attachment portion along the length of each attachment portion; and thus welded to the attachment portion along the edge of the wire mesh and substantially around the periphery of the wire mesh 260. The pre-tension force used to deflect the tensioning elements can then be released. The wire mesh 270 is thus tensioned in two orthogonal directions.

[0283] The pretension force can be applied by the following deflection elements (not shown) as described above with respect to frame 10: these deflection elements are capable of moving inward relative to the frame from the outside of all four frame members.

[0284] In an alternative embodiment, the first and second tensioning elements are deflected and secured to the wire mesh, and the deflecting elements are removed; then the entire assembly is rotated 90 degrees so that the same deflecting elements can be used to apply pretension to the third and fourth tensioning elements to secure the corresponding attachment portions to the wire mesh.

[0285] Figure 20 A cross-sectional view of another embodiment of the frame member 320, taken perpendicular to its length, is shown. The frame member 320 is formed of a sheet material such as steel. The frame member 320 includes a reference edge 322a at the apex between its upper side 322 and inner side 321 to define a horizontal line for printing the screen in use. It will be understood that the horizontal lines of the reference edges of the first and second frame members defining the frame, as well as typically the reference edges of the third and fourth frame members, will be coplanar (e.g., as shown). Figure 23 (as shown in the image).

[0286] Frame member 320 defines a generally box-shaped cross-section portion, generally indicated by 340, which extends to a safety guard portion (also referred to as a "finger guard") generally indicated by 342. A groove 324 is defined between the box-shaped cross-section portion and the safety guard portion.

[0287] The tensioning device 326 is attached to the frame member 320 by inserting a portion 326a of the tensioning device extending from its lower edge (in the direction shown in the figure) into the slot 324. In this attachment, the tensioning device has a fixed end 326a and a free end 326b, the free end 326b being configured for attachment to a printing screen as disclosed herein.

[0288] The fixed end 326a is held in the groove by friction between the inner surface of the groove and the sheet material of the tensioning device. Alternatively, for example, if it is not necessary to remove or replace the tensioning device, spot welding (e.g., using a laser) can be used to hold or further hold the tensioning device in the groove.

[0289] In alternative embodiments, the groove may be curved, kinked, or spiral, and the portion of the fixed end or tensioning device extending from the lower edge is correspondingly configured to serve as an interlocking arrangement.

[0290] The box-shaped section 340 includes an overlapping region 344 of two layers of sheet material. In the illustrated embodiment, the inner layer 344a is elastically pushed against the outer layer 344b, but spot welding or wire welding, joint fixing or mechanical fixing may be optionally used.

[0291] The distance between the inner wall 324a and the outer wall 324b of the groove 324 is substantially the same as the thickness of the sheet material of the tensioning device 326. In an alternative embodiment, the distance between walls 326a and 326b can be slightly narrower, such that walls 326a and 326b are slightly pushed away by the portion 326a of the tensioning device when it is inserted into the groove. In such an embodiment, the elasticity applied between the overlapping layers of the box-shaped cross-section acts as a "clamping force" to help hold the tensioning device in place.

[0292] The outer portion 323 of the box-shaped section 340 (or the outer portion of the frame member itself in an embodiment lacking finger protection) defines the inner wall 324a of the groove 324 and the abutment arrangement structure 328.

[0293] The abutment arrangement extends at an angle from the wall 324a of the groove toward the outer portion 321. In the illustrated embodiment, the abutment arrangement is generally vertical (in the direction shown in the figures), but in alternative embodiments, the abutment arrangement may be further angled toward the outer portion 321 or at a slightly smaller angle toward the outer portion 321. As disclosed herein, in other embodiments, the abutment arrangement may be curved.

[0294] The abutment arrangement structure 328 is spaced apart from the portion of the tensioning device 326 extending from the groove 324, such that the free end 326b of the tensioning device 326 is cantilevered.

[0295] The frame member 320 also includes a safety guard 346, which extends around the outside of the assembled frame and protects the outer edge of the printing screen during use; the outer edge of the printing screen may be sharp and could cause injury in some cases. The safety guard is provided with openings (discussed in further detail below) that allow a deflection element to enter and deflect the tensioning device during use.

[0296] To manufacture the frame member 320, a "blank" of the frame member 320 is produced in a steel sheet by: laser-cutting openings (not shown) for aligning the deflection element along the length that will form the abutment arrangement 328, aligning the entry openings along the length that will form the safety guard; and laser-cutting the outline of the frame member pattern. In alternative embodiments, the openings and outlines may be machined or otherwise formed by machining, or stamped from the sheet. As known to those skilled in the art, the frame member is then rolled, pressed, and / or stamped into the desired configuration.

[0297] Figure 21 and Figure 22 A cross-sectional view of the frame member 320 is shown during the process of attaching the tensioning device 326 to the frame member 320.

[0298] The frame member 320 is configured such that the vertical gap G between the innermost part of the safety guard 346 and the abutment arrangement structure 328 leaves space for the tensioning device 326 to be inserted vertically in the direction A.

[0299] The lower edge 326c of the tensioning device 326 contacts the inclined or curved surface 324c at the upper end of the groove 324 and is guided into the groove, thereby causing the tensioning device 326 to flex until the attachment portion 326b passes over the top of the safety guard 346. Figure 22 As shown, the attachment portion 326b of the tensioning element 326 can then be allowed to return to the "rest" position, and the tensioning element is inserted into the slot 324 generally along direction B.

[0300] The safety guard may optionally be provided with a lower opening 346l, through which a guide pin or rod (not shown) may be inserted to facilitate the flexing or guiding of the lower portion 326a of the tensioning device over the inclined surface 324c and into the groove 324.

[0301] As those skilled in the art will know, such attachment can be performed manually or automatically.

[0302] Figure 23A perspective view of a frame 310 for a printing screen assembly is shown. The frame 310 includes parallel elongated first frame members 320a and 320b, and parallel third and fourth frame members 320c and 320d. Frame members 320a, 320b, 320c, and 320d are constructed as described above with respect to frame member 320. The frame members are attached to each other at welded miter joints (see...). Figure 24 ), and therefore have a fixed relationship with each other.

[0303] An array of upper orifices 346u and access slots 350 located at each end of each frame member are visible along the outer safety guards of each frame member 320a-320d. Each frame member (members 320a and 320d) is visible along the outer safety guards of each frame member 320a-320d. Figure 24 (Visible in the middle) It has miter joints (i.e., diagonal) ends 360a, 360b. The ends of the frame members are welded along the accessible portions of the miter joint ends to attach the frame members to each other.

[0304] Figure 25 This is a side view of frame 310 as seen along the Z direction. The corresponding tensioning device 4326 and its attachment portion 4326b are visible through the opening 426u in the outer safety guard of the fourth frame member 320d. The abutment arrangement structure 328a of the first frame member 320a is also visible through the leftmost opening 346u in the attached drawing.

[0305] The tensioning device 1326 of the first frame member 320a is visible through the access slot 350. The corresponding slot passes through the safety guard of the third frame member 320c and is positioned at the other end of the tensioning device 1326.

[0306] After the tensioning device is attached, the safety guard may obstruct access to the tensioning device. Access slot 350 facilitates the removal of the tensioning device via slot 350 by applying force to the tensioning device along the length of the respective frame member at the opposite side of the frame.

[0307] The tensioning device 2326 of the second frame member 320b and the tensioning device 3326 of the third frame member 320c are in Figure 23 As can be seen, these tensioning devices can be attached to the respective frame members before or after they are attached to each other.

[0308] Figure 26 and Figure 27 A cross-sectional view of the frame member 320 is shown, and the pre-tensioning of the tensioning device 326 is illustrated.

[0309] A deflecting element 329, in the form of a pin or rod, is introduced through an upper orifice 326u in the safety guard 326. It will be understood that the tensioning device will be deflected in use by inserting an array of corresponding pins 329 along the length of the frame member 320 through an array of orifices 346u. Typically, the deflecting elements will be introduced to opposite sides or all four sides of the frame 310 to deflect the tensioning device simultaneously.

[0310] Pin 329 has a tapered tip portion 329a extending to a wider diameter rod portion 329b. A flange 329c extends around the tapered tip portion 329a at the distal end of the rod portion 329b. To deflect and pre-tension the tensioning device 326, the rod 329 advances in direction D such that the tip 329a extends through an upper orifice 326u through the tensioning device 326 and an orifice 328u through the abutment arrangement structure 328, as shown. Figure 27 As shown in the diagram. Observed along direction D, orifices 326u, 328u, and 346u are substantially aligned.

[0311] The diameter of the orifice 326u is smaller than the diameter of the rod portion 329b, such that when the rod 329 advances, the flange 329c abuts against the tensioning device 326 around the orifice 326u, causing the tensioning device 326 to deflect toward and contact the abutting arrangement structure 328, as shown. Figure 28 As shown in the image.

[0312] When the tensioning device is in the like Figure 26 In the "rest" position shown, the predetermined distance between the abutment arrangement structure 328 and the free end 326b of the tensioning device 326 ensures that the tensioning device, as shown... Figure 28 When the device deflects as shown to come into contact with the abutment arrangement structure 328, a predetermined amount of elastic potential energy is stored in the tensioning device 326.

[0313] In this pre-tensioned position, the attachment portion at the free end 328b of the tensioning device can be approached via gap G. Therefore, the printing screen can be attached to this attachment portion in any manner disclosed herein (e.g., as referenced above). Figure 6 , Figure 7 as well as Figures 9 to 12 (As described).

[0314] When the deflection element 329 is subsequently removed, the printing screen is in a taut state under the action of the elastic tensioning device, and the printing screen is pulled taut above the reference edge 322a.

[0315] While exemplary embodiments have been described herein, these exemplary embodiments should not be construed as limiting modifications and variations within the scope of the invention as disclosed herein and as set forth in the appended claims.

Claims

1. A method for constructing a printing screen assembly, the method comprising: A frame is provided, the frame having an elongated first frame member and an elongated second frame member that is parallel to the first frame member and in a fixed relationship; And corresponding cantilevered first and second tensioning devices extending from each frame member along the length of each frame member; Apply a pretension force to cause the first tensioning device to elastically deflect toward the second frame member and contact the first abutment arrangement structure of the first frame member; While the first tensioning device is in contact with the first abutting arrangement structure, the printing screen is fastened to the attachment portion of the first tensioning device; Secure the printing screen to the attachment portion of the second tensioning device; as well as The pre-tension force is released from the first tensioning device to apply tension to the printing screen.

2. The method of claim 1, further comprising elastically deflecting the second tensioning device toward the first frame member and contacting a second abutting arrangement structure of the second frame member; While the second tensioning device is in contact with the second abutting arrangement structure, the printed screen is fastened to the attachment portion of the second tensioning device; and The pretension force is released from the second tensioning device.

3. The method according to claim 2, wherein, The frame includes an elongated third frame member and an elongated fourth frame member parallel to the third frame member; and corresponding cantilevered third and fourth tensioning devices extending from each of the third and fourth frame members along the length of each frame member; wherein the third and fourth frame members extend substantially between the first and second frame members and are orthogonal to the first and second frame members; The method further includes: Apply a pretension force to cause the third tensioning device to elastically deflect toward the fourth frame member and contact the third abutment arrangement structure of the third frame member; and Apply a pretension force to cause the fourth tensioning device to elastically deflect toward the third frame member and contact the fourth abutment arrangement structure of the fourth frame member; The printing screen is fastened to the attachment portions of the third and fourth tensioning devices, while a pre-tension force is applied to the third and fourth tensioning devices; and The pre-tension force is released from the third tensioning device to apply tension to the printing screen.

4. The method according to claim 1, wherein, Each tensioning device independently includes a single elongated tensioning element, two or more tensioning elements; and / or, wherein each abutment arrangement independently includes a single elongated abutment portion or includes two or more abutment portions.

5. The method according to claim 2, wherein, The pretension force is applied to the first tensioning device by using at least one first deflection element; the method includes moving the at least one first deflection element from a first side of the first frame member located outside the frame toward the first frame member.

6. The method of claim 5, further comprising applying a pre-tension force to the second tensioning device using at least one second deflection element; the method comprising moving the at least one second deflection element from a second side of the second frame member located outside the frame toward the second frame member.

7. The method of claim 4, further comprising pre-selecting the tension applied by at least one of the tensioning devices, wherein, Each tensioning device includes or is formed of an elastic sheet material, and the tension applied by the tensioning device or each tensioning device is pre-selected by one or more of the following methods: removing material from the elastic sheet material; The elastic sheet material is machined and / or etched to selectively reduce the thickness in one or more regions of the elastic sheet material; the distance between the corresponding abutment arrangement structure and the tensioning device in a stationary position.

8. The method according to claim 7, wherein, Cut one or more slots, cuts or holes in the elastic sheet material, or cut one or more slots, cuts or holes from the elastic sheet material, to control the bending characteristics of the tensioning device or each tensioning device.

9. The method according to claim 7, wherein, Cut one or more slots or slits in the tensioning device or the elastic sheet material of each tensioning device, or cut one or more slots or slits from the elastic sheet material, to define more than two tensioning elements.

10. The method according to any one of claims 7 to 9, comprising laser processing or etching the elastic sheet material.

11. The method according to any one of claims 7 to 9, comprising changing the tension applied by at least one tensioning device along the length of the respective frame member.

12. The method according to any one of claims 1 to 9, wherein, The tensioning device is manufactured by bending an elastic sheet material to form one or more attachment portions and / or one or more interlocking structures.

13. The method according to any one of claims 1 to 9, comprising attaching each tensioning device to a corresponding frame member.

14. The method of claim 13, further comprising attaching each tensioning device by inserting a portion of the tensioning device into a slot or channel defined by the frame member.

15. The method according to claim 14, wherein, Each tensioning device includes a tensioning element interlocking structure, and each frame member includes a corresponding frame member interlocking structure, wherein each tensioning device is attached via an interlocking arrangement structure including the tensioning element interlocking structure and the frame member interlocking structure.

16. The method according to claim 15, wherein, The interlocking structure of the frame components is a groove, channel, or recess.

17. The method according to any one of claims 1 to 9, comprising forming each frame member and / or each tensioning device from an elastic sheet material.

18. The method of claim 17, wherein the elastic sheet material is bent by roll forming, stamping and / or pressing to form each frame member and / or each tensioning device.

19. The method according to any one of claims 1 to 9, comprising securing the printed screen to each attachment portion by welding.

20. The method of claim 19, further comprising securing the printed screen to each attachment portion by using laser welding.

21. The method according to any one of claims 1 to 9, wherein, The printing screen includes hook-shaped portions extending along the length of the printing screen, the length of which substantially corresponds to the length along which each tensioning device extends; wherein the method includes hooking each hook-shaped portion to a corresponding attachment portion of each tensioning device.

22. The method according to claim 21, wherein, Each hook-shaped portion is integral with the printing screen, wherein each hook-shaped portion is formed by bending along the edge of the elastic sheet material of the printing screen.

23. The method of claim 21, further comprising attaching each hook portion to the printing screen.

24. The method of claim 23, further comprising laser welding each hook portion to the printing screen.

25. A printing screen assembly, comprising: A frame having an elongated first frame member and an elongated second frame member, the second frame member being parallel to and fixed to the first frame member; A cantilevered first tensioning device and a cantilevered second tensioning device extend from each respective frame member along the length of the respective frame member; each tensioning device includes an attachment portion located along the length at or near the free end of each tensioning device; Wherein, the first frame member includes a first abutting arrangement structure; wherein, the first tensioning device is operable to elastically deflect toward the second frame member to contact the first abutting arrangement structure; and A printing screen, the printing screen being attached to the attachment portions of a first tensioning device and a second tensioning device and being kept taut between the attachment portions; wherein, when the first tensioning device is deflected to contact the first abutment arrangement structure, the tension in the printing screen is determined by the pretension applied to the first tensioning device.

26. The printing screen assembly according to claim 25, wherein, The second frame member includes a second abutment arrangement; wherein the second tensioning device is operable to elastically deflect toward the first frame member to contact the second abutment arrangement; wherein, when the first tensioning device and the second tensioning device deflect to contact the corresponding first abutment arrangement and the second abutment arrangement, the tension in the printing screen is determined by the pretension applied to the first tensioning device and the second tensioning device.

27. The printing screen assembly according to claim 25, wherein, The printed screen is welded, bonded, and / or fastened to each of the attachment portions via hook-shaped portions.

28. The printing screen assembly according to claim 25, wherein, Each tensioning device and / or each frame member includes or is formed of elastic sheet material.

29. The printing screen assembly according to claim 28, wherein, The elastic sheet material is stainless steel.

30. The printing screen assembly according to claim 28, wherein, The tension applied by the tensioning device or each tensioning device has been pre-selected by one or more of the following methods: removing material from the elastic sheet material; machining and / or etching the elastic sheet material; and the distance between the corresponding abutment arrangement structure and the tensioning device in a stationary position.

31. The printing screen assembly according to claim 30, wherein, At least one of the tensioning devices has a variable thickness, and / or wherein at least one of the tensioning devices includes one or more slots, cuts, or openings cut into or from the elastic sheet material to control bending characteristics.

32. The printing screen assembly according to any one of claims 25 to 31, wherein, The tensioning device is attached to the corresponding frame member.

33. The printing screen assembly according to claim 32, wherein, The tensioning device is removably attached to the corresponding frame member.

34. The printing screen assembly according to claim 33, wherein, The tensioning device is attached to the frame member by inserting a portion of the tensioning device into a slot or channel defined by the frame member.

35. The printing screen assembly according to any one of claims 25 to 31, wherein, Each frame component is cast, machined, or extruded into a single piece.

36. The printing screen assembly according to any one of claims 25 to 31, wherein, Each frame component is formed from a single elastic sheet material piece or an elastic sheet material blank.

37. The printing screen assembly according to any one of claims 25 to 31, wherein, Each frame component includes external safety guards.

38. The printing screen assembly according to claim 37, wherein, Each external safety guard includes one or more openings that facilitate access to the corresponding tensioning device via a deflection element.

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