CN210147858U

CN210147858U - Universal clamp

Info

Publication number: CN210147858U
Application number: CN201821734117.2U
Authority: CN
Inventors: 斯蒂芬·詹姆斯·戴蒙德; 周泽锋
Original assignee: P2i Ltd
Current assignee: P2i Ltd
Priority date: 2017-10-24
Filing date: 2018-10-24
Publication date: 2020-03-17
Anticipated expiration: 2028-10-24
Also published as: WO2019081922A1; TW201922441A

Abstract

A fixture for holding a workpiece, such as a printed circuit board, to perform one or more process steps thereon. The clamp includes two jaws separated by a clamping zone in which the workpiece is clamped. At least one of the jaws is provided with a plurality of teeth for contacting the workpiece holder at the clamping zone, each tooth being independently movable relative to the corresponding jaw. The independent movement of the teeth allows the fixture to hold workpieces of different shapes, sizes and configurations.

Description

Universal clamp

Technical Field

The present invention relates to a clamp for holding workpieces during one or more process operations, and more particularly to a clamp capable of holding workpieces of different shapes, sizes or arrangements.

Background

Often, it is necessary to clamp a printed circuit board or other similar item on a fixture to perform a process step. For example, when surface modifying an article (such as applying a coating on the article by vapor deposition), it is often necessary to mask the article so that a portion of the surface of the article is not modified. To do so, the masking may be performed by an automated process (e.g., robotic arm) and the items need to be placed in known locations to facilitate masking. For example, it is sometimes desirable to apply masking material to one or more areas of a component of a mobile device (such as a printed circuit board, screen, rear cover, or other article) prior to applying a vapor deposited coating to provide liquid-proofs for the unmasked areas.

The fixture may also be used to hold a printed circuit board or other article, such as mounting electronic components on a printed circuit board, during other process steps.

SUMMERY OF THE UTILITY MODEL

A fixture for holding a workpiece (e.g., a printed circuit board) for performing one or more process steps on the workpiece is provided. The fixture comprises two jaws which are separated by a clamping zone, wherein the workpiece is clamped in the clamping zone. At least one of the jaws has a plurality of teeth thereon for contacting a workpiece located in the clamping zone, each tooth being independently movable relative to the corresponding jaw.

One aspect of the present invention provides a clamp for clamping one or more workpieces. The clamp includes: a pair of jaws defining a clamping zone therebetween; at least one of the jaws is provided with a plurality of teeth, each tooth being independently movable relative to the corresponding jaw, each tooth being provided with a gripping surface for contacting a surface of a workpiece and gripping the workpiece in the gripping zone.

The independent movement of the teeth allows the fixture to hold workpieces having different shapes, sizes and configurations. For example, the fixture can be used to hold any flat workpiece of a relatively thin thickness. Thus, the workpiece may have two major faces enclosed by a pair of feathered edges. The workpiece may have any planar shape. The clamp can also hold workpieces having complex shapes. The workpiece has a length (i.e., the longest dimension through at least one major face thereof) of no more than 150mm and/or a width (i.e., the longest dimension perpendicular to the length direction through at least one major face thereof) of no more than 90 mm.

Each tooth-shaped part (or called a probe or a finger part) is provided with a main body part, and the main body part is provided with a corresponding clamping surface.

In a preferred embodiment of the invention, the one or more workpieces comprise one or more printed circuit boards, e.g. the one or more workpieces may comprise two printed circuit boards connected by a flexible connection. The one or more printed circuit boards may be single-sided, double-sided, or multi-layer printed circuit boards. The one or more printed circuit boards may include a substrate having one or more conductive tracks disposed thereon for electrically connecting one or more electronic components.

Each tooth is preferably movable away from the respective jaw from a retracted position to an extended position, and each tooth is biased towards the extended position.

Preferably, the jaws are biased towards each other. With this arrangement, the workpiece can be stably clamped between the jaws. Biasing the jaws toward each other reduces the width of the gripping area.

The jaws are preferably movable towards each other or away from each other along a common linear clamping direction, so that the jaws can be moved into alignment with each other, the force provided by the jaws being only in the clamping direction.

In a preferred embodiment of the invention, each tooth is movable along a linear tooth axis relative to the corresponding jaw, the tooth axes of the teeth of each jaw being parallel to each other. Thus, the teeth can move in alignment with each other, with the force exerted by each tooth on the workpiece being only along the direction of the corresponding tooth axis.

The tooth axis of each tooth is preferably parallel to the gripping direction of the jaws, so that the forces exerted on the workpiece by the jaws and the tooth are in the same direction.

Each tooth is provided with a gripping surface for engaging an edge of a workpiece. For example, each clamping surface may be provided with a V-shaped or U-shaped notch in which, in use, the edge of the workpiece is located. Similarly, each tooth may be provided with a recess on which the clamping surface is formed. By providing the clamping surfaces in the form of notches or depressions, slight misalignments between adjacent teeth (e.g. caused by manufacturing or assembly errors) may be absorbed.

Each tooth may be provided with a piston and cylinder assembly for providing movement relative to the corresponding jaw. For example, each tooth may comprise one or more pistons rigidly connected to the corresponding gripping surface, the one or more pistons being slidable in one or more cylinder bores respectively provided in the corresponding jaw. Alternatively, each tooth may comprise a cylinder bore in which a piston rigidly connected to the corresponding jaw may slide. In some embodiments of the invention, each tooth includes two piston and cylinder assemblies that move back and forth to provide movement of the tooth relative to the corresponding jaw.

Preferably, one or more of the plurality of teeth are shaped and/or sized differently than other one or more of the plurality of teeth. By varying the shape and/or size of the teeth, the ability of the fixture to grip workpieces of any shape or size may be further enhanced. For example, one or more of the plurality of teeth may have a different length than another one or more of the plurality of teeth in a direction of movement of the at least one jaw. Alternatively, one or more of the plurality of teeth may have a different shaped gripping surface than another one or more of the plurality of teeth.

The teeth of each jaw are preferably arranged in series along the jaw in such a way that the clamp can clamp a workpiece having opposed linear edges in one dimension. For example, the fixture may hold a relatively flat, thin workpiece.

The clamp is preferably provided with an opening device operable to allow the jaws to move away from each other to allow removal of the workpiece from the clamp. The opening device may comprise any manual or powered device, for example, the opening device may comprise a mechanical, electromechanical, electrical or hydraulic actuator.

According to the utility model discloses a preferred embodiment, opening device includes a pair of hinge arm, and corresponding jaw is connected to the one end of each hinge arm, and the hinge joint is connected to the other end, and wherein, the hinge joint can move to the open position. In the open position, the hinge arms are rotated away from each other such that the jaws are separated. So arranged, a simple means of opening the jaws may be provided, especially in combination with the feature that the jaws may be moved towards or away from each other along a common linear clamping direction. The opening device can be actuated by a key or the like to move the hinge joint to the open position.

Preferably, the clamp includes a mounting subassembly and a rotatable subassembly including a pair of jaws, wherein the rotatable subassembly is mounted on the mounting subassembly and is rotatable relative to the mounting subassembly. So configured, all edges/faces of one or more workpieces held by the fixture can be inspected or process steps performed on the workpieces. In some embodiments, the process steps are performed on the workpiece held in the fixture by an automated production machine, such as a robotic arm configured to apply a coating (i.e., a layer of masking material) to the workpiece, and rotation of the workpiece relative to the machine may minimize the complexity and associated expense of the machine. For example, only one robot arm may be provided to perform process steps on both sides of the workpiece.

The rotatable subassembly may rotate relative to the mounting subassembly about one or two axes, wherein the two axes may be substantially perpendicular to each other. In some embodiments of the present invention, the rotatable subassembly may rotate about three axes.

The rotatable sub-assembly may preferably comprise a jaw mounting plate, each jaw being mountable on the jaw mounting plate by a sliding connection and being slidable relative to the jaw mounting plate to provide relative movement between the jaws.

The clamp may include one or more bearings connecting the mounting subassembly and the rotatable subassembly.

The jig preferably includes control means to control the rotational position of the rotatable sub-assembly relative to the mounting sub-assembly.

A second aspect of the present invention provides a method of operating a clamp according to the first aspect of the invention and/or any of the features and/or embodiments described herein, comprising the steps of: placing the clamp in an open position; inserting a workpiece into the clamping zone between the jaws; the jaws are brought into a clamping position by bringing the jaws closer together so that the clamping face of one or more of the plurality of teeth contacts the surface of the workpiece and clamps the workpiece in the clamping zone.

The method of the present invention further includes rotating the jaw portion relative to the mounting subassembly of the fixture to rotate the workpiece held in the holding area. The jaw is rotatable between a first position and a second position: in the first position, a first side of the workpiece may be subjected to a first process step; in the second position, the second side of the workpiece may be subjected to a second process step. The angle between the first position and the second position is about 180 degrees. The first and second process steps may comprise steps performed by the same production equipment, i.e. equipment for performing the first and second process steps.

In some embodiments of the invention, the method further comprises performing a process step on the workpiece. For example, the process step includes applying a surface layer, such as a coating, on the workpiece. The surface layer may include a masking material that may be applied to one or more regions of the workpiece to prevent surface modification of the one or more regions prior to exposing the workpiece to the surface modifying conditions. Optionally, the surface layer may comprise an adhesive layer.

The method of the present invention may include performing a first process step on a first side of a workpiece and performing a second process step on a second side of the workpiece. In a preferred embodiment of the invention, the method further comprises, after performing the first process step, before performing the second process step, rotating the jaw from the first position to the second position. Preferably, the jaws are rotated about 180 degrees from the first position to the second position. The first and second process steps are preferably carried out by the same production apparatus, i.e. an apparatus for carrying out the first and second process steps.

A third aspect of the invention provides a method of performing a process step on one or more workpieces, comprising the steps of: according to the first aspect of the invention and/or optional features and/or any embodiment described herein, the one or more workpieces are clamped with a clamp; and performing a process step on the one or more workpieces. In some embodiments of the invention, the process step may include applying a surface layer, such as a coating, on the one or more clamped workpieces. For example, the surface layer may include a masking material. Masking material is applied to one or more regions of the workpiece prior to exposing the one or more clamped workpieces to surface modifying conditions to prevent surface modification of the one or more regions. Alternatively, the surface layer may comprise an adhesive layer.

The method of the present invention comprises applying a first process step to a first side of a workpiece and applying a second process step to a second side of the workpiece. According to a preferred embodiment of the present invention, the method further comprises: after the first process step is performed and before the second process step is performed, the jaws are rotated from the first position to the second position. Preferably, the jaw is rotated approximately 180 degrees from the first position to the second position. The first and second process steps are preferably performed by the same production equipment, i.e. equipment for performing the first and second process steps.

The masking process of the various aspects of the present invention includes, but is not limited to, the removal of masking material applied after the surface modification process.

The masking material may be in any desired form consistent with achieving the desired masking properties or effects.

According to some embodiments of the invention, the masking material comprises a cured resin, in particular, the masking material is liquid in the uncured state and solid in the cured state. The method of the present invention may also include curing the resin after application.

Suitably, the resin is preferably radiation curable, such as UV curable. Such masking materials are known in the art and include polymerizable monomers or oligomers, photoinitiators or various additives such as antioxidants, fillers and thickeners. Examples of suitable polymerizable monomers include substituted vinyl compounds, especially acrylate compounds.

The UV curable resins useful in the present invention preferably include acrylate urethanes, e.g., substituted or unsubstituted urethane methacrylates or urethane acrylates, such as the compositions sold by DymaxRTM under the tradename DymaxRTM 9-20479-B, DymaxRTM 9-20318-F, and DymaxRTM 9-318-F.

However, other types of masking materials may be used in the method of the present invention.

The masking material may comprise multiple units of masking material, for example, the masking material may comprise multiple points or other regions of masking material. The method of the present invention may include applying a plurality of discrete units of masking material.

In the present invention, and in particular in the second and third aspects of the invention, examples of surface modification processes include, but are not limited to, deposition processes, in particular particle or vapour deposition processes. The surface modification process may be carried out at sub-atmospheric pressure, i.e. comprising exposing the one or more masking articles to sub-atmospheric pressure. Suitably, the sub-atmospheric pressure is from 0.01 to 999.99mbar, such as from 0.1 to 999.99mbar, or from 0.5 to 999.99 mbar. In some embodiments of the present invention, the surface modification process is a sub-atmospheric vapor deposition process, in particular a plasma polymerization process.

For example, the conditions for surface modification may be vapor deposition conditions. The surface modification conditions may include sub-atmospheric pressure. In one embodiment of the present invention, the vapor deposition conditions are plasma polymerization conditions.

The conditions for surface modification may include: an excitation medium; and a monomer at least partially activatable by the excitation medium to form a liquid-repellent coating on the article. The excitation medium comprises a plasma or a pulsed plasma.

The monomer may be a compound of formula (I):

wherein R is¹，R²And R³Independently selected from hydrogen, alkyl, haloalkyl or aryl substituted with halo; r⁴Is a group X-R⁵Wherein R is⁵Is alkyl or haloalkyl, X is a bond; x is of the formula-C (O) O (CH)₂)_nA group of Y, wherein n is an integer of 1 to 10, Y is a bond or a sulfonamide group; or X is- (O)_PR⁶(O)_q(CH₂)_tWherein R is⁶Is aryl optionally substituted with halogen, p is 0 or 1, q is 0 or 1, t is 0 or an integer from 1 to 10, and t is not 0 when q is 1.

Suitably, the workpiece may be exposed to a plasma comprising the monomeric compound for a sufficient time to allow a protective polymeric coating to form on the surface of the workpiece; wherein the monomer compound has the following formula (II):

wherein R is¹，R²And R⁴Each independently selected from hydrogen, optionally substituted branched or straight chain C₁-C₆Alkyl or haloalkyl or aryl substituted by halogen, R₃Selected from:

wherein each X is independently selected from hydrogen, optionally substituted branched or straight chain C1-C6 alkyl, haloalkyl or aryl optionally substituted with halo; n is₁Is an integer from 1 to 27.

In some embodiments, the monomer may be as described in the claims of WO 2007/083122.

Suitably, the monomer may be selected from 1H,1H,2H, 2H-perfluorohexyl acrylate (PFAC4), 1H,2H, 2H-perfluorooctyl acrylate (PFAC6), 1H,2H, 2H-perfluorodecyl acrylate (PFAC8) and 1H,1H,2H, 2H-perfluorododecyl acrylate (PFAC 10).

Suitably, the masked article may be exposed to the monomer compound in combination with a cross-linking agent comprising two or more unsaturated bonds linked by means of one or more linking moieties, having a boiling point at standard pressure below 500 ℃. The crosslinking agent may be selected from 1, 4-butanediol divinyl ether (BDVE), 1, 4-cyclohexanedimethanol divinyl ether (CDDE), 1, 7-octadiene (17OD), 1,2, 4-Trivinylcyclohexane (TVCH), divinyl adipate (DVA), 1, 3-divinyltetramethyldisiloxane (DVTMDS), diallyl 1, 4-cyclohexanedicarboxylate (DCHD), dodecafluoro-1, 9-Decadiene (DVPFH), 1H,1H,6H, 6H-perfluorohexanediol diacrylate (PFHDA) and tetraallyloxyethane (GBDA).

The surface modification conditions may form a coating that is liquid repellent, such as water and/or oil repellent.

The one or more workpieces may be of any desired type, and in one embodiment of the invention, the one or more workpieces include one or more printed circuit boards, electronic devices, or electronic components.

Throughout the description and claims of this application, the terms "comprise" and "contain" and variations thereof such as "comprises" and "comprising" mean "including but not limited to", without excluding other elements, additives, components, integers or steps. Furthermore, the singular forms may have the plural unless the context requires otherwise. In particular, where the indefinite article is used, the specification is to be understood as embracing the plural and singular meanings unless the context requires otherwise.

Preferred features of the various aspects of the invention may be described in connection with any other aspect. Within the scope of the present application, the various aspects, embodiments, examples and alternatives described in the preceding paragraphs, claims and/or the following figures and description, particularly the various features thereof, may be independent or in any combination. In other words, features of all embodiments and/or any embodiment may be combined and/or grouped in any manner unless such features are incompatible.

Drawings

One or more embodiments of the present invention are described in detail below with reference to the accompanying drawings, wherein:

figure 1 is a schematic view of one embodiment of the clamp of the present invention wherein the rotatable subassembly of the clamp is in a first rotational position.

FIG. 2 is a schematic view of the clamp of FIG. 1, wherein the rotatable subassembly of the clamp is in a second rotational position.

Fig. 3 is a schematic view of the fixture of fig. 1 and 2 with a workpiece held therein.

Fig. 4 is a schematic view of a tooth adapted for use in the fixture of fig. 1-3.

Fig. 5A and 5B are top and bottom views of a PCB held in one embodiment of the clamp of the present invention.

Fig. 6A and 6B are top and bottom views of the jig for holding a PCB shown in fig. 5A and 5B, in which the PCB is located at different positions.

Fig. 7 is a schematic view of another embodiment of the clamp of the present invention.

FIG. 8 is a schematic view of the clamp of FIG. 7, wherein the clamp is in an open position.

Fig. 9 is a schematic view of the clamp of fig. 7 and 8, with the clamp in a rotated position and holding a workpiece.

Fig. 10 is a schematic view of another embodiment of the present invention, wherein the clamp is in a clamping position.

FIG. 11 is a schematic view of the clamp of FIG. 10, wherein the clamp is in an open position.

Fig. 12 is a schematic view of a tooth suitable for use in the clip of fig. 10 and 11.

Detailed Description

Fig. 1-4 illustrate a clamp 100 according to an embodiment of the present invention, the clamp 100 including a rotatable subassembly 10, the rotatable subassembly 10 being rotatable relative to a stationary mounting subassembly 12 between a first rotational position, shown in fig. 1, and a second rotational position, shown in fig. 2. As described below, the rotatable subassembly 10 is used to hold a workpiece (e.g., a printed circuit board), and rotation of the rotatable subassembly 10 allows process steps (e.g., manufacturing or inspection steps) to be performed on either major surface of the workpiece.

The rotatable subassembly 10 includes a jaw mounting frame 20 having first and second long jaw mounting plates 22, the first and second long jaw mounting plates 22 being rigidly connected to one another at opposite ends by first and second long engagement plates 24 to form an open four sided frame 20. The first and second shaft portions 26 extend in opposite directions from each of the joint plates 24 such that the rotational axes thereof are aligned.

The rotatable subassembly 10 is mounted to the stationary mounting subassembly 12 by first and second bearings 30, the stationary mounting subassembly 12 including first and second stationary bearing mounting plates 32, each stationary bearing mounting plate 32 being provided with an opening in which the outer edges of the bearings 30 are mounted by interference fit, mechanical fixation or other suitable rigid fixation. The first shaft portion 26 of the mounting frame 20 is mounted to the inner edge of the first bearing 30 by an interference fit, mechanical fastening, or other suitable rigid fastening. Similarly, the second shaft portion 26 of the mounting frame 20 is mounted to the inner edge of the second bearing 30. So configured, the first and second shaft portions 26 are free to rotate relative to the stationary bearing mounting plate 32, and thus, the rotatable subassembly 10 can rotate about the shaft relative to the stationary mounting subassembly 12.

The jaw mounting frame 20 is provided with first and second sliding jaws 40, each sliding jaw 40 being provided with a generally rectangular mounting plate, the first jaw 40 being mounted on the first mounting plate 22 and the second jaw 40 being mounted on the second mounting plate 22 such that the opposed faces of the jaws 40 are provided with toothed mounting faces 42 separated by clamping zones 50. In use, one or more printed circuit boards (PCBs, not shown in fig. 1 and 2) are held in the holding area 50.

The first jaw 40 is mounted to the first jaw mounting plate 22 by a slide 28, the slide 28 allowing the first jaw 40 to move relative to the first jaw mounting plate 22 by translational movement only in the clamping direction. Similarly, the second jaw 40 is mounted on the second jaw mounting plate 22 by a slide 28, the slide 28 allowing the second jaw 40 to move relative to the second jaw mounting plate 22 by translational movement only in the clamping direction. The clamping direction is perpendicular to the axis of rotation of the rotatable subassembly 10 and allows each jaw 40 to move closer to or further away from the axis of rotation. Thus, relative movement between the first and second jaws 40 can cause the tooth mounting surfaces 42 to move toward or away from each other, narrowing or widening the gripping region 50.

Each tooth mounting face 42 of each jaw 40 supports a plurality of teeth 60, each tooth 60 being provided with a plastic gripping body 62, the plastic gripping body 62 being substantially rectangular parallelepiped with a V-shaped notch therein to define a gripping face 64. The teeth 60 are arranged in linear succession along the tooth mounting surface 42 such that in the neutral position (shown in fig. 1 and 2), the V-shaped notches of the gripping surfaces 64 are aligned and form aligned long notches. Each tooth 60 is separated from adjacent teeth 60 by a gap to allow relative movement therebetween.

The gripping body 62 of each tooth 60 is rigidly mounted to a pin 66 or pair of pins 66, with each pin 66 being slidably mounted in a corresponding bore 46 of the jaw 40 such that the pin 66 is movable in the bore 46 in a piston and cylinder assembly. Referring to FIG. 4, one or more springs 72 bias each tooth 60 away from the tooth mounting face 42 of the respective jaw 40.

Each pin moves in a corresponding hole 46 along a tooth axis aligned with the gripping direction, and each tooth 60 is arranged to move along the corresponding tooth axis toward or away from the other one of the first and second jaws 40, independently relative to the corresponding first or second jaw 40, and relative to the other tooth 60. Thus, the position of the gripping surface 64 of each tooth 60 relative to the corresponding jaw (relative to the neutral position) is variable.

Fig. 4 is an exploded view of the tooth 60 showing the structure of each pin 66. The fixed end bar 67 is provided with a threaded portion 68 and a hollow circular portion 69, the threaded portion 68 interfacing with a threaded portion in the corresponding jaw 40. An inner rod 70 is inserted into the hollow circular portion 69 and positioned (e.g., by an interference fit) within the hollow circular portion 69 by a ring-shaped fixed rod pin 71 to surround the inner rod 70. A portion of the inner rod 70 extends from the hollow circular portion 69 of the fixed end bar 67 to interface with the base of the circular recess in the corresponding toothed gripping body 62. A spring 72 located between the gripping body 62 and the fixed end bar 67 biases the gripping body 62 away from the fixed end bar 67.

It will be appreciated by those skilled in the art that the gripping body 62 of each tooth may be configured in any of a number of different ways to suit the shape and size of the printed circuit board being gripped. In the illustrated embodiment, each tooth 60 has one of three different configurations of a gripping body 62: the long holder 62a has the longest length in the tooth axis direction, and the middle holder 62b and the short holder 62c have shorter lengths in the tooth axis direction. The middle holding body 62b is provided with a holding surface 64, the holding surface 64 has a V-shaped notch, and the V-shaped notch on the holding surface 64 is shallower than the notches on the long holding body 62a and the short holding body 62 c. The middle holder 62b is narrower than the long holder 62a and the short holder 62c in the direction of the rotation axis R, and is fitted to only one pin 66. By providing a plurality of gripping bodies 62, the ability of the fixture 100 to accommodate printed circuit boards of any of a variety of sizes or shapes may be further enhanced.

Referring to fig. 3, the rotatable subassembly 10 is provided with an opening device 70, the opening device 70 being operable to move the jaws 40 between an open position and a clamping position: in the open position, the jaws are moved away from each other to widen the clamping zone; in the clamping position, the jaws are brought closer together to narrow the clamping area and clamp the printed circuit board 90.

The opening device 70 comprises a pair of hinge arms 72, each hinge arm 72 having one end connected to the positioning rod 71 by a hinge joint and the other end connected to the corresponding jaw 40 by a similar hinge joint. Referring to fig. 1 and 2, the detent lever 71 is slidable in a bore 76 through the first shaft portion 26 between an extended position and a retracted position: in the extended position, the hinge arms 72 open through a wide angle, and the jaws 40 are driven away from each other to an open position; in the retracted position, the hinge arms are opened through a narrow angle and the jaws 40 are driven closer to each other to the clamping position. The positioning rod 74 is spring driven to the retracted position and the jaw 40 is biased toward the gripping position.

In this embodiment, the positioning rod 74 is moved between the retracted position and the extended position by operating a key (not shown) to engage the positioning rod 74 and position the positioning rod 74 in the hole 76. The key can be operated manually or electrically by means of an electric motor and suitable gearing. In some embodiments, the key may include a linear actuator, such as a hydraulic, pneumatic, electric, magnetic, or mechanical actuator.

The rotatable subassembly 10 may be rotated relative to the stationary mounting subassembly 12 by manual operation, or by a motor and suitable transmission. Each shaft portion 26 of the rotatable subassembly 10 includes a pair of circular slots 27 or through-holes into which a corresponding pair of tabs of a handle or motor interface may interface to rotate the rotatable subassembly 10.

Because of the independent movement of the teeth 60 on each jaw 40, the fixture 100 can hold printed circuit boards (or other workpieces) having irregular shapes. Referring to fig. 3, a printed circuit board 90 having a non-straight edge is held in a holder 100.

Fig. 5A, 5B and 6A, 6B also show a schematic view of the clamp of the present invention, wherein an irregularly shaped workpiece is held between two or more teeth 60 of the clamp. In fig. 5A and 5B, the printed circuit board 92 is held in a first direction, and in fig. 6A and 6B, the same printed circuit board 92 is held in a second direction perpendicular to the first direction. The printed circuit board 92 has an irregular, non-straight profile and is accommodated by the independent movement of the teeth 60.

In use, to insert a workpiece (e.g., printed circuit boards 90,92) into the clamping zone 50, the clamp 100 is moved from the open position to the extended position by moving the positioning rods 74 of the opening device 70 and driving the jaws 40 away from each other. This movement widens the clamping zone 50 and allows the workpiece to be positioned in the clamping zone 50. Subsequently, by moving the positioning rod 74 of the opening device 70 to the retracted position, the clamp 100 is moved to the clamping position and drives the jaws 40 closer to each other to narrow the clamping zone 50. When the gripping surfaces 64 of the tooth 60 contact the

workpieces

90,92, the gripping bodies 62 of the tooth 60 overcome the biasing action of the springs, respectively, and move independently along the respective tooth axes toward the respective tooth mounting surfaces 42. Each pin 66 moves only in the corresponding hole 46 to ensure that the workpiece is held stably and that the workpiece edge clearance can be accommodated. To remove the

workpieces

90,92, the clamp is returned to the open position.

Fig. 7 to 9 show a second embodiment of the present invention, the illustrated clamp 200 is substantially the same as the clamp 100 shown in fig. 1 to 6, and the following description will focus on different technical features.

The clamp 200 includes a rotatable subassembly 110 that can rotate relative to a stationary mounting subassembly 112. The rotatable subassembly 110 is used to hold a workpiece, such as a printed circuit board as described below. The rotation of the rotatable subassembly 110 allows process steps (such as manufacturing steps or inspection steps) to be performed on either major surface of the workpiece.

The rotatable subassembly comprises a jaw mounting frame 120 comprising a U-shaped rigid member, the two limbs of the jaw mounting frame 120 being provided with first and second jaw mounting plates 122. The shaft portion 126 extends from the base of the U-shaped jaw mounting frame 120 in a direction opposite to the direction in which the first and second jaw mounting plates 122 extend.

The rotatable subassembly 110 is mounted to the stationary mounting subassembly 112 by a bearing 130, the stationary mounting subassembly 112 including a bearing mounting plate 132 provided with an opening in which the outer edge of the bearing 130 is mounted by an interference fit, mechanical fastening, or other suitable rigid fastening. The shaft portion 126 of the mounting frame 120 is mounted to the inner edge of the first bearing 130 by an interference fit, mechanical fastening, or other suitable rigid fastening. So configured, the shaft portion 126 is free to rotate relative to the stationary bearing mounting plate 132, and thus, the rotatable subassembly 10 is rotatable about the axis of rotation R relative to the stationary mounting subassembly 12.

The jaw mounting frame 120 is provided with first and second sliding jaws 140, each jaw 140 being provided with a generally rectangular plate, the first jaw 140 being mounted on the first mounting plate 122 and the second jaw 140 being mounted on the second mounting plate 122 such that opposing faces of the jaws 140 include toothed mounting faces 142 separated by a clamping zone 150 in which, in use, one or more printed circuit boards (such as the printed circuit board 190 shown in figure 9) can be clamped in the clamping zone 150.

The first jaw 140 is mounted to the first jaw mounting plate 122 by the slider 128, allowing the first jaw 140 to move relative to the first jaw mounting plate 122 by translation only in the clamping direction C. Similarly, the second jaw 140 is mounted to the second jaw mounting plate 122 by the slider 128, allowing the second jaw 140 to move relative to the second jaw mounting plate 122 by translation only in the clamping direction C. The clamping direction C is perpendicular to the axis of rotation R of the rotatable subassembly 110, allowing each jaw 140 to move closer to or farther away from the axis of rotation. Thus, relative movement of the first and second jaws 140 causes the tooth mounting surfaces 142 to move toward or away from each other, narrowing or widening the gripping region 150.

Each slide 128 includes a first portion 128a rigidly connected to the jaw mounting frame 120 and a second portion 128b rigidly connected to the corresponding jaw 140. First portion 128a and second portion 128b are connected by a pair of rails 129 to allow relative sliding movement between first portion 128a and second portion 128b to provide movement for the gripping direction C of jaw 140.

Each tooth mounting face 142 of each jaw 140 supports a plurality of teeth 160, each tooth 160 being provided with a plastic gripping body 162, the plastic gripping body 162 being generally rectangular parallelepiped and having a V-shaped notch therein to define a gripping face 164. The teeth 160 are linearly spaced one after the other along the tooth mounting surface 142 such that in the neutral position shown in fig. 7, the V-shaped notches of the gripping surfaces 164 are aligned and form aligned long notches. Each tooth 160 is separated from adjacent teeth 160 by a small gap and allows relative movement between adjacent teeth 160.

The gripping body 162 of each tooth 160 is rigidly mounted on a pair of pins 166, and each pin 166 is slidably mounted in a bore 146 provided in a corresponding jaw 140 such that the pins 166 move in the bores 146 in a piston and cylinder assembly. One or more springs (not shown) bias each tooth 160 away from the tooth mounting face 142 of the corresponding jaw 140.

Each pin 166 moves in a corresponding hole 146 along a tooth axis aligned with the gripping direction C, so that each tooth 160 is independently movable relative to the corresponding first and second jaws 140, and independently movable relative to the other teeth 160 along the respective tooth axis toward or away from the teeth 160 mounted on the first and second jaws 140. Thus, the position of the gripping surface 164 of each tooth 160 relative to the corresponding jaw (and relative to the neutral position) may vary.

It will be appreciated by those skilled in the art that the gripping body 162 of each tooth may be provided in any of a variety of different forms to match the shape and size of the printed circuit board to be gripped. In the embodiment shown in fig. 7 to 9, each tooth 160 has an identical gripping body 162.

The rotatable sub-assembly 110 is provided with an opening device 170, the opening device 170 being capable of moving the jaw 140 between an open position and a clamping position. In the open position, the jaws are moved away from each other to widen the clamping zone 150; in the clamping position, the jaws are brought closer together to narrow the clamping area 150 and clamp a workpiece, such as a printed circuit board.

The opening device 170 comprises a pair of hinge arms 172, each of which has one end connected to a positioning rod 174 by means of a hinge joint and the other end connected to the second portion 128b of the corresponding slider 128 of the rigid connection jaw 140 by means of a similar hinge joint. The positioning rod 174 is slidably received in a hole 176 formed through the shaft portion 126 and is slidable between an extended position and a retracted position. In the extended position, the hinge arms 172 open through a wide angle, and the jaws 140 are separated from each other to an open position. In the retracted position, the hinge arms are opened through a narrow angle and the jaws are brought closer to each other to the clamping position. The positioning rod 174 is driven to the retracted position by the action of a spring (not shown), and the jaw 140 is biased to the gripping position.

Referring to FIG. 8, the positioning rod 174 may be moved between the retracted position and the extended position by operation of a key 180. The key 180 is provided with a circular portion 182, and the circular portion 182 may be inserted into the aperture 176 to drive the positioning rod 174 toward the extended position against the action of the spring. In this embodiment, the key 180 is operated manually, but in other embodiments the key may be operated by a motor and suitable gearing, or by a linear actuator (such as a hydraulic, pneumatic, electric, magnetic or mechanical actuator), or by other actuators that may be remotely controlled. The key disclosed in this embodiment can be applied to the first embodiment.

Referring to FIG. 9, the rotatable sub-assembly 10 is rotatable relative to the stationary mounting sub-assembly 12 via the interface connector 186. The interface connector 186 is provided with a pair of projections 188, the projections 188 being arranged to interface with a corresponding pair of circular grooves 127 or through-holes in the shaft portion 126. The interface connector 186 may be rotated manually by a handle or by a motor and suitable gearing to rotate the rotatable subassembly 10 to facilitate performing process steps on either side of a workpiece 190 (fig. 9) held by the fixture 200. The interface connector disclosed in this embodiment is also applicable to the first embodiment.

In use, to insert a workpiece (e.g., a printed circuit board) into the clamping area 150, the clamp 200 is moved to the open position by moving the positioning rods 174 of the opening device 170 to the extended position such that the jaws 140 are separated from each other. The movement widens the clamping area 150 so that the workpiece can be loaded. Subsequently, the clip 200 is moved to the clipping position by moving the positioning rod 174 of the opening device 170 to the retracted position, and causing the jaws 140 to approach each other and the clipping region 150 to be narrowed. Because the gripping surfaces 164 of the tooth 160 are in contact with the workpiece, the gripping bodies 162 of the tooth each move along the corresponding tooth axis independently toward the respective tooth mounting surface 142 against the biasing action of the spring. Each pin 166 moves only in the corresponding hole 146 to ensure that the workpiece can be held stably with the workpiece edge profile received. To remove the workpiece, the clamp 200 is returned to the open position.

Fig. 10 to 12 are schematic views of a third embodiment of the present invention, and the jig 300 of the present embodiment is particularly easy to form. The fixture 300 is shown in fig. 10 in a clamping position with the fixture 300 clamping a workpiece, which in the illustrated embodiment is a printed circuit board 290 (PCB). The clamp 300 is shown in fig. 11 in an open position with the clamp open to facilitate removal or insertion of a workpiece.

The clip 300 includes first and second jaws 240, each of the first and second jaws 240 being movable relative to the jaw mounting portion 220. For example, each jaw mounting portion 220 includes a cylinder 222 rigidly mounted to a stationary mounting frame (not shown) or mounted to a rotatable mounting frame. Each cylinder 222 is provided with a plurality of bores 224 (3 bores in the illustrated embodiment), and a piston 226 is slidable in each bore 224 in the manner of a cylinder and piston assembly. The pistons 226 are arranged to move back and forth to move the respective jaws 240 closer to or further away from the corresponding cylinder 222 in the clamping direction C.

Each jaw 240 is movable only in translation along the gripping direction C, the jaws 240 having opposing faces to provide tooth mounting faces 242 separated by gripping zones 250. In use, one or more printed circuit boards, such as printed circuit board 290 shown in fig. 10 and 11, are held within holding area 250. Thus, relative movement of the first and second jaws 240 causes the tooth mounting surfaces 242 to move toward or away from each other and narrow or widen the gripping region 250.

The tooth mounting portion 242 of each jaw 240 supports a plurality of teeth 260, and in this embodiment, the tooth mounting portion 242 supports 10 teeth 260. Each tooth 260 is provided with a gripping body 262, the gripping body 262 being movable along a toothed axis with respect to a pin 266, the pin 266 being rigidly connected to the corresponding jaw 240. Each gripping body 262 is generally circular and has a V-shaped notch in an end surface thereof to define a gripping surface 264. The teeth 260 are linearly spaced one after the other along the tooth mounting surface 242 such that in the neutral position (no workpiece being clamped in the fixture 300), the V-shaped notches of the clamping surfaces 264 are aligned and form aligned long notches. Each tooth 260 is separated from an adjacent tooth 260 by a small gap to allow relative movement therebetween.

Each gripping body 262 is movable relative to the corresponding pin 266 along a tooth axis aligned with the gripping direction C, so that each tooth 260 is independently movable relative to the corresponding first or second jaw 240, closer to or further from the teeth 160 mounted on the first and second jaws 140, relative to the other teeth 260 along the corresponding tooth axis. Thus, the position of the gripping surface 164 of each tooth 160 relative to the corresponding jaw (relative to the neutral position) may vary. The gripping body 262 and gripping face 264 of each tooth 260 can be offset from the corresponding tooth mounting surface 242 and biased toward the workpiece to be gripped by the gripping region 250.

Fig. 12 is an exploded view of the tooth 260 showing the configuration of the pin 266. The fixed end rod 267 is provided with a threaded portion 268 which interfaces with a threaded portion in the corresponding jaw 240, and a hollow circular portion 269. The inner rod 270 is inserted into the hollow circular portion 269 and positioned within the hollow circular portion 269 by a ring-like fixed rod pin (e.g., by an interference fit) such that it surrounds the inner rod 270. A portion of the inner rod 270 extends from the hollow circular portion of the fixed end rod 269 to interface with a circular recess in the corresponding tooth-like portion of the clamping body 262. A spring 272 located between the clamping body 262 and the fixed end bar 267 biases the clamping body 262 away from the fixed end bar 267.

It will be appreciated by those skilled in the art that the gripping body 262 of each tooth may be provided in any of a variety of different forms to match the shape and size of the printed circuit board to be gripped. In the embodiment shown in fig. 10 to 12, each tooth 260 has an identical gripping body 262.

In use, to insert a workpiece (e.g., printed circuit board 290) into clamping area 250, clamp 300 is moved to the open position shown in fig. 11, wherein pistons 266 are retracted into bores 224 in cylinder block 222 in a clamping direction C (as indicated by arrow R). This movement widens the clamping zone 250 and the workpiece 290 can be located in the clamping zone 250. Subsequently, the clamp 300 is moved to the clamping position shown in fig. 10, at which time the piston 266 is driven out of the corresponding bore 224 in the clamping direction (as indicated by arrow D) to narrow the clamping zone 250. When the gripping surfaces 264 of the tooth 260 contact the workpiece 290, the gripping bodies 262 of the tooth move independently in the direction indicated by arrow T along the respective tooth axes against the biasing action of the springs 272. Each gripping body 262 is only movable relative to the corresponding pin 266 to ensure that the workpiece is gripped stably and the workpiece edge profile can be accommodated. To remove the workpiece, the clamp 300 is returned to the open position.

In various aspects of the embodiments and descriptions of the present invention, a clamp is used to clamp a workpiece, such as a printed circuit board; or a plurality of workpieces, such as a plurality of printed circuit boards or an assembly of a plurality of printed circuit boards. Each workpiece is preferably a planar workpiece of relatively thin thickness. Each workpiece is thus provided with two main faces which are encompassed by the thinner sides. Each workpiece may have any planar shape, particularly planar shapes having a complex perimeter. Each workpiece has a length (longest dimension across at least one major face thereof) of no more than 150mm and/or a width (longest dimension perpendicular to the length across at least one major face thereof) of no more than 90 mm.

Each workpiece may be manually placed into the clamping area of the fixture or may be placed into the clamping area of the fixture by an automated device such as a robotic arm. The use of robotic arms may facilitate the highly repeatable placement of multiple identical workpieces into the fixture.

In each embodiment, the elements may be formed of any suitable material. However, the gripping portion of the tooth is preferably made of a plastics material and the other elements may be made of a suitable metal or metal alloy.

In all of the embodiments described above, one or more zones of masking material may be applied to the surface of a workpiece held in the fixture 100,200,300 by a robotic arm (not shown). The rotatable sub-assembly 10,110,210 may thus be rotated 180 degrees about the axis of rotation R and one or more regions of masking material may be applied to the opposite side of the workpiece by the robotic arm. Thus, a single robotic arm may be used to operate on both sides of the workpiece. The workpiece is then removed from the fixture and exposed to surface modification conditions, such as vapor deposition conditions, by placing the workpiece in a plasma polymerization deposition chamber. In some cases, the workpiece is returned to the fixture 100,200,300 after the surface modification process to remove some or all of the area of the masking material.

According to one embodiment of the present invention, the vapor deposition process comprises exposing the workpiece to vapor deposition conditions as disclosed in WO2007/083122, the entire contents of WO2007/083122 being incorporated herein by reference in its entirety.

In another embodiment of the invention, the vapor deposition conditions further comprise a crosslinker selected from the group consisting of 1, 4-butanediol divinyl ether (BDVE), 1, 4-cyclohexanedimethanol divinyl ether (CDDE), 1, 7-octadiene (17OD), 1,2, 4-Trivinylcyclohexane (TVCH), divinyl adipate (DVA), 1, 3-divinyltetramethyldisiloxane (DVTMDS), diallyl 1, 4-cyclohexanedicarboxylate (DCHD), dodecafluoro-1, 9-Decadiene (DVPFH), 1H,1H,6H, 6H-perfluorohexanediol diacrylate (PFHDA) and tetraallyloxyethane (GBDA).

Claims

1. A universal fixture for holding one or more workpieces, the fixture comprising:

a pair of jaws defining a clamping zone therebetween; and

at least one jaw provided with a plurality of teeth, each tooth being independently movable relative to the corresponding jaw, and each tooth being provided with a clamping surface to contact a surface of a workpiece and clamp the workpiece in a clamping zone.

2. The universal fixture of claim 1, wherein the one or more workpieces comprise one or more printed circuit boards.

3. The universal fixture of claim 1 or 2, wherein each tooth is movable relative to the corresponding jaw from a retracted position to an extended position, and each tooth is biased toward the extended position.

4. The universal fixture of claim 1, wherein said jaws are biased toward each other.

5. The universal fixture of claim 1, wherein said jaws move toward and away from each other along a common linear clamping direction.

6. The universal fixture of claim 1, wherein each tooth is movable relative to the corresponding jaw along a linear tooth axis, and the tooth axes of the teeth of each jaw are substantially parallel to each other.

7. Universal clamp according to claim 5 or 6, characterized in that the axes of the teeth are respectively parallel to the clamping direction of the jaws.

8. The universal fixture of claim 1, wherein each tooth includes a recess, the clamping surface being formed on the recess.

9. The universal fixture of claim 1, wherein each tooth includes a piston and cylinder assembly providing movement of the tooth relative to the corresponding jaw.

10. The universal fixture of claim 1, wherein each tooth includes two piston and cylinder assemblies movable back and forth to provide movement of the tooth relative to the corresponding jaw.

11. The universal fixture of claim 1, wherein one or more of said plurality of teeth and one or more of the other of said plurality of teeth have different shapes and/or sizes.

12. The universal fixture of claim 1, wherein one or more of said plurality of teeth and one or more of the other plurality of teeth have different lengths in a direction of movement of at least one jaw.

13. The universal fixture of claim 1, wherein one or more of the plurality of teeth and one or more of the other plurality of teeth have different shaped clamping surfaces.

14. The universal fixture of claim 1, wherein the teeth of each jaw are aligned in sequence along the jaw.

15. The universal fixture of claim 1 further comprising an opening device operable to separate the jaws to allow removal of a workpiece from the fixture.

16. The universal fixture of claim 15, wherein the opening device comprises a pair of hinge arms, each hinge arm having one end connected to a corresponding jaw and another end connected to a hinge joint, wherein the hinge joints are movable to an open position in which the hinge arms are biased away from each other to separate the jaws.

17. The universal fixture of claim 1, further comprising a rotatable subassembly provided with a pair of jaws and a mounting subassembly, wherein the rotatable subassembly is mounted on and rotatable relative to the mounting subassembly.

18. The universal fixture of claim 17, wherein the rotatable subassembly is provided with jaw mounting plates, each jaw being mounted to and slidable relative to the jaw mounting plate via a sliding connection to provide relative movement between the jaws.

19. The universal fixture of claim 17, further comprising one or more bearings connecting the mounting subassembly and the rotatable subassembly.

20. The universal fixture of claim 17, further comprising a control device to control a rotational position of the rotatable subassembly relative to the mounting subassembly.