Alignment apparatus and methods of alignment

Abstract

An alignment dowel comprises a body extending along a longitudinal axis, the body comprising a plurality of resilient vanes that extend generally perpendicular to the longitudinal axis, and an actuator portion. The stack has openings of a predetermined diameter. The vanes are arranged around the longitudinal axis so as to extend along the axis and project radially outwards to define an outer diameter of the body. The actuator portion is operable to move the vanes between a collapsed configuration in which the outer diameter is smaller than the predetermined diameter, and an expanded configuration in which the outer diameter of the body is greater than in the collapsed configuration. A stack assembly jig, comprises a tool base on which a stack of components can be positioned. The tool base has guide holes that are no smaller than the predetermined diameter and are positioned to correspond to the position of the openings in the stack. A base plate carries an array of alignment dowels arranged to correspond to the positions of the guide holes. The base plate is moveable relative to the tool base such that the alignment dowels can project through the guide holes and into the component openings. The actuators are operable to align the components in the stack. A method for aligning components of a cell stack using an alignment dowel, comprises arranging cells adjacent one another in a stack, wherein the cells have internal alignment features, wherein each alignment feature includes an engaging surface with which the alignment dowel is configured to engage and disengage when located within said alignment feature; and locating the alignment dowel in the alignment features in the collapsed configuration and operating the actuator to move the alignment dowel to the expanded configuration to align the cells.

Claims

1. A method for aligning a plurality of components of a cell stack using an alignment dowel, wherein the alignment dowel comprises: an elongate body extending along a longitudinal axis, the body comprising resilient elongate vanes arranged around the longitudinal axis so as to extend along the longitudinal axis and project radially outwards from the longitudinal axis to define an outer diameter of the body, and an actuator portion; wherein the actuator portion is operable to move the vanes between a collapsed configuration in which the outer diameter is smaller than a predetermined diameter, and an expanded configuration in which the outer diameter of the body is greater than in the collapsed configuration; the method comprising: arranging a plurality of cells adjacent one another in a stacked configuration, wherein the cells have internal alignment features provided within components of each cell that allow them to be aligned relative to one another, wherein each alignment feature includes an engaging surface with which the vanes of the alignment dowel are configured to selectively engage and disengage when located within said alignment feature; and locating the alignment dowel in the alignment features in the collapsed configuration and operating the actuator to move the vanes of the alignment dowel to the expanded configuration to engage the engaging surfaces of the alignment features to align the cells.

2. A method according to claim 1, further comprising: arranging a plurality of gaskets interposed between adjacent cells, each gasket defining a gasket opening; and locating the alignment dowel in the alignment features and the gasket openings in the collapsed configuration and operating the actuator to move the alignment dowel to the expanded configuration to align the cells and gaskets.

3. A method according to claim 1, wherein the internal alignment features of the cells define a common datum opening, of the method comprising: arranging the cells and gaskets adjacent one another in a stacked configuration such that the common datum openings and the gasket openings define a passageway; and locating said alignment dowel within the passageway in the collapsed configuration and operating the actuator to move the alignment dowel to the expanded configuration to align the gaskets with the cells.

4. A method according to claim 1, wherein the alignment dowel comprises at least three resilient vanes.

5. A method according to claim 4, wherein each resilient vane is curved, and all vanes are curved in the same direction.

6. A method according to claim 4, wherein each resilient vane is bent, and all vanes are bent in the same direction.

7. A method according to claim 1, wherein the body comprises a central rod which carries the resilient vanes that extend outward from the rod.

8. A method according to claim 7, wherein the resilient vanes are attached to the rod along their length.

9. A method according to claim 7, wherein the resilient vanes form a spiral around the rod.

10. A method for assembling a stack of components comprising: aligning a plurality of components of a cell stack using an alignment dowel, comprising: arranging a plurality of cells adjacent one another in a stacked configuration, wherein the cells have internal alignment features provided within components of each cell that allow them to be aligned relative to one another, wherein each alignment feature includes: an engaging surface with which the alignment dowel is configured to selectively engage and disengage when located within said alignment feature; and locating the alignment dowel in the alignment features in the collapsed configuration and operating the actuator to move the alignment dowel to the expanded configuration to align the cells; wherein the alignment dowel comprises: an elongate body extending along a longitudinal axis, the body comprising resilient elongate vanes arranged around the longitudinal axis so as to extend along the longitudinal axis and project radially outwards from the longitudinal axis to define an outer diameter of the body, and an actuator portion; wherein the actuator portion is operable to move the vanes between a collapsed configuration in which the outer diameter is smaller than a predetermined diameter, and an expanded configuration in which the outer diameter of the body is greater than in the collapsed configuration; the method further comprising assembling a stack of components using an assembly jig comprising: a tool base on which a stack of components can be positioned, wherein the components define openings of the predetermined diameter and the tool base defines guide holes that are no smaller than the predetermined diameter and are positioned to correspond to the position of the openings of the components in the stack; and a base plate carrying an array of alignment dowels, wherein the alignment dowels are arranged to correspond to the positions of the guide holes; wherein the base plate is moveable relative to the tool base such that the alignment dowels can project through the guide holes and into the component openings, and wherein the actuators are operable to align the components in the stack; wherein the method comprises: positioning a stack of components on the tool base such that the openings overlap with the guide holes; moving the base plate with the vanes on the dowels in the collapsed configuration so that the dowels project through the guide holes and the openings; and operating the actuators so that the vanes move to the expanded configuration so as to align the components.

11. A method according to claim 10, wherein the base plate is located below the tool base and can be raised so that the alignment dowels project into the component openings.

12. A method according to claim 10, further comprising, after alignment of the components: operating the actuator to return the vanes to the collapsed configuration; adding further components to the stack so that the dowels project through the openings of the further components; and operating the actuators so that the vanes move to the expanded configuration so as to align the further components.

13. A method according to claim 12, further comprising moving the base plate closer to the tool base so that the dowels project further from the tool base as the height of the stack increases.

14. A method for aligning a plurality of components of a cell stack using an alignment dowel, comprising: arranging a plurality of cells adjacent one another in a stacked configuration, wherein the cells have internal alignment features provided within components of each cell that allow them to be aligned relative to one another, wherein each alignment feature includes: an engaging surface with which the alignment dowel is configured to selectively engage and disengage when located within said alignment feature; and locating the alignment dowel in the alignment features in the collapsed configuration and operating the actuator to move the alignment dowel to the expanded configuration to align the cells; wherein the alignment dowel comprises: an elongate body extending along a longitudinal axis, the body comprising resilient elongate vanes arranged around the longitudinal axis so as to extend along the longitudinal axis and project radially outwards from the longitudinal axis to define an outer diameter of the body, and an actuator portion; wherein the actuator portion is operable to move the vanes between a collapsed configuration in which the outer diameter is smaller than a predetermined diameter, and an expanded configuration in which the outer diameter of the body is greater than in the collapsed configuration; wherein the alignment dowel further comprises a central rod and an array of elongate tubes arranged around the rod, wherein each tube is substantially parallel to the rod and carries a resilient vane that projects outward from the array.

15. A method according to claim 14, wherein each vane projects tangentially from the tube on which it is carried.

16. A method according to claim 14, wherein the alignment dowel comprises at least three tubes.

17. A method according to claim 14, wherein each resilient vane is curved, and all vanes are curved in the same direction.

18. A method according to claim 14, wherein each resilient vane is bent, and all vanes are bent in the same direction.

19. A method according to claim 14, wherein each tube can be rotated so as to adjust the outward projection of its vane and so adjust the outer diameter of the body.

20. A method according to claim 19 wherein the actuator comprises a rotatable collar positioned around a first end of the array, wherein each tube includes a formation at a first end that engages in a corresponding formation in the collar such that rotation of the collar relative to the array acts to rotate each tube to adjust the outer diameter of the body.

21. A method according to claim 20, wherein the dowel further comprises a bracket positioned at a second, opposite end of the array, wherein the bracket includes formations that engage with the tubes to maintain the tubes parallel to the central rod.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cross-section through a first embodiment of an alignment dowel.

(2) FIG. 2 is an end view of the alignment dowel of FIG. 1.

(3) FIG. 3 is a perspective view of the alignment dowel of FIG. 1.

(4) FIG. 4 is a cross-sectional view through the alignment dowel of FIG. 1 in use.

(5) FIG. 5 shows a partially assembled fuel cell stack with alignment dowels of FIG. 1 inserted.

(6) FIG. 6 shows a partial top view of a metal supported solid oxide fuel cell unit of the partially assembled fuel cell stack of FIG. 5 without an alignment dowel inserted in the passageway.

(7) FIG. 7 shows a partial top view of a metal supported solid oxide fuel cell unit of the partially assembled fuel cell stack of FIG. 5, with a section through an alignment dowel inserted in the passageway.

(8) FIG. 8 is a cross-section through a second embodiment of an alignment dowel.

(9) FIG. 9 is a cross-section through the alignment dowel of FIG. 8 in use.

(10) FIG. 10 is a perspective view of a third embodiment of an alignment dowel.

(11) FIG. 11 is an end view of the dowel of FIG. 10.

(12) FIG. 12 is a perspective view of a fourth embodiment of an alignment dowel.

(13) FIG. 13 is an end view of the dowel of FIG. 12.

(14) FIG. 14 is a perspective view of a fifth embodiment of an alignment dowel with three vanes.

(15) FIG. 15 is an end view of the dowel of FIG. 14.

(16) FIG. 16 is a cross-section through a sixth embodiment of an alignment dowel.

(17) FIG. 17 is a cross-section through a seventh embodiment of an alignment dowel.

(18) FIG. 18 shows an alignment dowel according to an eighth embodiment in a collapsed configuration.

(19) FIG. 19 shows an end part of the alignment dowel of FIG. 18.

(20) FIG. 20 shows a tube carrying a resilient vane.

(21) FIG. 21 shows the alignment dowel of FIG. 18 in an expanded configuration.

(22) FIG. 22 shows an end part of the alignment dowel of FIG. 21.

(23) FIG. 23 shows a top bracket for use with the alignment dowel of FIG. 18.

(24) FIG. 24 shows a stack assembly jig.

(25) FIGS. 25-28 show the stack assembly jig of FIG. 24 in the stages of assembly of a cell stack.

(26) FIG. 29 shows a further form of vane.

DETAILED DESCRIPTION

(27) It will be apparent to those of ordinary skill in the art that various modifications and variations can be made in the present invention without departing from the scope of the claims.

1.SUP.st .Embodiment

(28) In the first embodiment (FIGS. 1-6), the alignment dowel 10 comprises a body section 20 comprising a central rod 30 from which extends a set of seven resilient vanes 40 which are curved in a clockwise direction (i.e., resilient vanes 40 are attached to the solid central rod 30 along their length). At one end of the alignment dowel 10 there is located an actuator 50 which is used to insert and remove the alignment dowel 10 from passageways in a stack of components, and to rotate the alignment dowel 10.

(29) A passageway 60 is defined by common datum openings of a plurality of fuel cells (not shown) and gasket openings of corresponding gaskets 70 interposed between adjacent fuel cells. The cells and gaskets are arranged adjacent one another in a stacked configuration.

(30) In use, the alignment dowel 10 is rotated using the actuator 50 in an anti-clockwise direction (when viewed from above) and inserted into the passageway 60, the anti-clockwise rotation reducing friction of resilient vanes 40 with the fuel cells and gaskets and easing insertion. The alignment dowel 10 is then rotated in a clockwise direction to increase the friction on resilient vanes 40. This results in resilient vanes 40 causing any misaligned gaskets 70 to be moved and aligned. The actuator 50 has a smaller diameter than the outer diameter of resilient vanes 40.

(31) In this embodiment, the vanes 40 have a continuous surface. In other embodiments (see, e.g., FIG. 12), vanes can be slotted.

(32) As shown in FIGS. 5-7, a partially assembled fuel cell stack 100 comprises a metal supported solid oxide fuel cell units 110 with interposed gaskets 70. Examples of metal supported solid oxide fuel cell units 110 are described in WO 2019/034855.

(33) Each fuel cell unit 110 defines passageways 60 (fuel ducts). In this example there is one in each corner. An alignment dowel 10 is inserted in each passageway 60. The fuel cell units 110 are rigidly aligned against a hard external datum (not shown). but the gaskets 70 are free to move relative to the fuel cell units 110 and are constrained by the mass of fuel cell unit(s) 110 on top of them. The alignment dowels 10 act to provide a soft datum against which the gaskets 70 are aligned—when a predetermined number of fuel cell units 110 and interposed gaskets 70 have been stacked, an alignment dowel 10 is inserted into each passageway 60 and actuated to align gaskets 70 with fuel cell units 10. The alignment dowels 10 are then removed from the passageways 60.

2.SUP.nd .Embodiment

(34) The second embodiment (FIGS. 8 and 9) corresponds generally to the first embodiment. In the second embodiment the resilient vanes 42 are not pre-curved, i.e., are substantially radial in the expanded/unconstrained configuration.

3.SUP.rd .Embodiment

(35) The third embodiment (FIGS. 10 and 11) corresponds generally to the first embodiment. In the third embodiment the resilient vanes 44 are angled relative to the radial direction (as opposed to, e.g., being curved as in the first embodiment).

4.SUP.th .Embodiment

(36) The fourth embodiment (FIGS. 12 and 13) corresponds generally to the first embodiment. In the fourth embodiment the resilient vanes 46 are intermittent (they can also be described as being “slotted”), and the central rod 32 is hollow.

5.SUP.th .Embodiment

(37) The fifth embodiment (FIGS. 14 and 15) corresponds generally to the first embodiment. The fourth embodiment comprises three resilient vanes 47 which are fabricated from spring steel and project tangentially from the central rod 30.

6.SUP.th .Embodiment

(38) The sixth embodiment (FIG. 16) differs from the previous embodiments in that it does not comprise a central rod. Instead, the body comprises two curved resilient vanes 48 which are joined directly to one another along long edges.

7.SUP.th .Embodiment

(39) The seventh embodiment (FIG. 17) is similar to the sixth embodiment in that it does not comprise a central rod. In the seventh embodiment the body comprises four curved resilient vanes 49 which are joined directly to one another along long edges.

8.SUP.th .Embodiment

(40) FIGS. 18-23 show an eighth embodiment of an alignment dowel 200. The dowel comprises a central rod 210 mounted in a base 211 with a series of tubes 212 arranged around the exterior of the rod 210. The rod 210 and tubes 212 are substantially parallel. The rod 210 and tubes are shown as hollow but can also be solid. Each tube 212 carries a resilient vane 214 connected to its outer surface. Each vane 214 extends tangentially from its tube 212 and is curved. When arranged around the central rod 210, the vanes 214 all project and curve in the same direction and adjacent vanes are overlapped.

(41) Each tube 212 can be rotated around its longitudinal axis. This has the effect of adjusting the amount by which each vane 214 projects in the radial direction. In the embodiment shown, when viewed from above, rotation of the tubes 212 in an anti-clockwise direction causes the vanes 214 to project more so that the outer diameter of the dowel increases. Conversely, rotation in a clockwise direction causes the vanes 214 to project less. FIGS. 18 and 19 show the dowel in a collapsed configuration (lower outer diameter) and FIGS. 20 and 21 show the same dowel in an expanded configuration (higher outer diameter).

(42) Each tube 212 has a formation in the form of a radially projecting peg 216 at its lower end that extends outwardly from the dowel. An actuator in the form of a rotatable collar 218 is mounted at the bottom of the dowel. The collar 218 has a series of cut-out formations 220 around the end of the dowel. A peg 216 engages in each cutout 220. Rotating the collar 218 relative to the central rod 210 causes the cutouts to move the pegs to one side or the other. This in turn causes the tubes to rotate and expand or collapse the vanes 212. The collar can be locked in the expanded or collapsed position by means of a locating pin 221. Other arrangements of formations can also be used. For example, the positions of the pegs and cutouts could be reversed, or a toothed gear arrangement could be used.

(43) A bracket 222 is located at the top of the dowel (shown separated in FIG. 23). The bracket is secured to the central rod 210 and has projecting formations 224 that engage in the ends of the tubes 212 to hold them in position relative to the rod 210 while allowing them to rotate about their longitudinal axis.

(44) FIGS. 24-28 show a stack assembly jig comprising dowels according to the eighth embodiment. The jig 230 has a tool base 232 for supporting the stack of components. The tool base 232 has a series of guide holes 234 what are arranged to correspond to the layout of passages 60 in the fuel cell units 110. A base plate 236 is positioned below the tool base 232. The base plate 236 has dowels 200 mounted on an upward-facing surface and arranged to correspond to the arrangement of guide holes 234 in the tool base 232.

(45) In an initial position, the dowels 200 are in the collapsed configuration and project partially through the guide holes 234 (FIG. 24). Fuel cell units 110 and gaskets 70 are placed over the dowels 200 to rest on the tool base 232 (FIG. 25). Each dowel 200 is actuated into the expanded configuration by rotation of the collars 218 so that the vanes 214 are moved outwards to engage with the inner surfaces of the passageways 60 in the fuel cell units 110 and gaskets 70 so as to urge them into alignment (FIG. 26). The dowels 200 are then actuated into the collapsed configuration (FIG. 27). At this point, further fuel cell units 110 and gaskets 70 can be placed over the dowels 200 to increase the size of the stack. Additionally, or alternatively, the base plate 236 can be raised so that the dowels 200 project further through the guide holes 234 to allow further fuel cell units 110 and gaskets 70 can be placed over the dowels 200 to increase the size of the stack (FIG. 28). Once the stack is complete, the dowels 200 are returned to the collapsed configuration, the base plate 236 lowered, and the stack removed.

9.SUP.th .Embodiment

(46) The ninth embodiment (FIG. 29) is similar to the eight embodiment. However, in this case, the vanes 215 are bent rather than curved, i.e., each blade is formed of a substantially flat portion with one or more bends so that the blade is deviated from a single plane. Combinations of flat portions, bends, and curves can also be used to achieve the same effect.

(47) Various modifications, adaptations and alternative embodiments will be readily apparent to the person of ordinary skill in the art without departing from the scope of the appended claims.