CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 63/395382 filed on August 5, 2022, the content of which is relied upon and incorporated herein by reference in its entirety.

BACKGROUND

[0002] The present disclosure relates to glass stacking and handling. More specifically, the present disclosure relates to an alignment system for kinematic stacking glass sheets. [0003] Stacks of glass sheets are used in industrial processes to perform the same operation on the side edges of the glass sheets in a batch rather than on individual glass sheets. These operations can include finishing the sides. Finishing processes can include, for example, grinding, polishing, chamfering, painting, coating, screen printing, and the like. A series of glass sheets is typically stacked and then held together for processing all at once. However, problems can occur such as shifting of glass sheets within the stack causing part misalignment and/or scratching.

[0004] Surface scratch specifications are challenging to meet. The stacking and unstacking operations and relative shifting in-process can cause scratches, many of them sufficiently deep to impact surface quality, optical characteristics, and finished part mechanical edge strength.

[0005] Where glass part positioning is concerned, numerous methods have been developed and some are in use today to position spacers between glass parts and build batch part stacks with reasonable precision. However, as the glass stack is clamped individual spacer and/or glass part shifting can occur causing stacking positioning errors. This shifting can be due to the compressive nature of the spacer material, the part/ spacer flatness, a twisting motion due to the clamp application methods, or any combination of these effects. [0006] Additionally, lateral forces applied to a plurality of parts (such as in stack form) are proportionally higher than those experienced by substrates in single part processing operations. Process failures using existing tooling can happen due to inherent unreliable application of a clamp force holding the glass sheets together in the stack.

[0007] As throughput requirements increase, increased stack sizes are economically beneficial. SUMMARY OF THE DISCLOSURE

[0008] To overcome the problems described above, embodiments of the present disclosure permits users to quickly and repeatably build positionally accurate work pieces such as glass stacks. The disclosed alignment system provides flexibility to make changes to dimensional offsets within the glass stack and four-sided processing of the glass stack once built.

[0009] Four sided processing stacks of similar glass sheets separated by spacers has a large throughput advantage when compared with processing single glass sheets. This type of bulk processing has several applications including edge finishing and printing on the edges of the glass sheets. The disclosed alignment and fixturing system provides precise, repeatable glass stack fabrication with sustained integrity even when subjected to lateral forces associated with batch finishing processing. The glass stack alignment system maximizes surface protection to the value areas of the glass sheets while minimizing possible scratching. [0010] The disclosed alignment and fixturing system permits the user to build an accurate stack of glass sheets and alternating spacer layers of different sizes, while maintaining accessibility to all four edges of the glass stack for processing. The alignment system includes adjustable shafts and high tolerance locators. The fixturing concept can be adopted to accommodate a wide range of stack offset parameters with minimal effort.

[0011] This solution is simpler and more easily accommodates a wide range of stack offset parameters than existing methods of stack building. It also allows for four-sided processing of the stack after it is built.

[0012] The above and other features, elements, characteristics, steps, and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. l is a perspective view of an alignment system according to an embodiment of the present disclosure.

[0014] FIG. 2 is a perspective view of an arm assembly.

[0015] FIG. 3 is a perspective view of the alignment assembly mounted to the arm assembly.

[0016] FIG. 4 is a rear perspective view of the alignment assembly.

[0017] FIG. 5 is a front view of the alignment assembly.

[0018] FIG. 6 is a view of the alignment assembly and a component stack. [0019] FIG. 7 is a side sectional view of the alignment assembly.

[0020] FIG. 8 is a view of a shaft.

[0021] FIG. 9A and FIG. 9B are perspective views of a shaft support.

[0022] FIG. 10, FIG. 11, and FIG. 12 are views of locators.

[0023] FIG. 13A and FIG. 13B are views of the bottom plate.

[0024] FIG. 14A and FIG. 14B are views of the top plate assembly.

[0025] FIG. 15A and FIG. 15B are perspective views of the clamp assembly.

[0026] FIG. 16A and FIG. 16B are perspective views of additional embodiments.

DETAILED DESCRIPTION

[0027] A rigid body in space has six degrees of freedom. In a conventional Cartesian coordinate system these are translations in X, Y, and Z directions (axes) and rotations about each of these axes. An idealized kinematic constraint would have six points of contact constraining these six degrees (idealized because all contact points deform under pressure). [0028] The disclosed alignment system relies on kinematic comer nesting to align each layer in a part (glass) stack to pre-set datums. A set of shafts, independently adjustable along slots, set by a user, provide these datums. Some of the shafts are used to locate the layers in the stack. Other shafts provide datums for locating other components of the stack that do not have the same footprint as the glass sheets in the stack. These other components can include base/top plates, spacer or interposer layers, etc. Although the disclosed alignment and fixturing system is described as being applied to a stack of glass sheets, the alignment system can be used in stacking and handling other rigid planar substrates made with ceramic, plastic, composite, metal, silicon, wood, or any other suitable material.

[0029] Once the stack components are properly located, a force can be applied to the stack locking the components together. A clamp bracket can be affixed to the locked stack in such a way that allows the stack to rotate 360 degrees within the clamp bracket.

[0030] FIG. 1 is a perspective view of an alignment system 100 according to an embodiment of the present disclosure. FIG. 1 shows that the alignment system 100 can include several components and subassemblies such as an arm assembly 110, an alignment assembly 120, a clamp assembly 130, a bottom plate 140, and a top plate assembly 1400. A glass stack GS is shown between the bottom plate 140 and the top plate assembly 1400. The fixturing system 100 is shown as mounted to a base plate 190 but the fixturing system 100 can be mounted to or set to rest on any suitable stabilizing structure such as a work bench, table top, breadboard, etc. [0031] FIG. 2 is a perspective view of an arm assembly 110. FIG. 2 shows that the arm assembly 110 can include a base 11 land an arm 113. As shown, the base 111 can be substantially planar or plate shaped and can include through holes 112 used to mount or stabilize the arm assembly 110 to a mounting surface such as a larger plate, a bench top, or other suitable working surface. Also as shown, the arm 113 can be mounted to and/or extend upwardly from the base 111. The arm 113 can be generally cubic shaped with an inclined face 114 and include mounting holes 115 in the inclined face 114 used to attach an alignment assembly. Optionally, the base 111 and the arm 113 of the arm assembly 110 can be any suitable configuration that can securely hold an alignment assembly and a clamp assembly. [0032] FIG. 3 is a perspective view of the alignment assembly 120 mounted to the arm assembly 110. As shown, the alignment assembly 120 can include a base plate 121 that includes slots 122 used to locate shafts 123, and though holes 124 for mounting the alignment assembly 120 to the arm assembly 110. Hardware used to mount the alignment assembly 120 to the arm assembly 110 is omitted for clarity. The base plate can also include two mounting slots 124, one each on opposing sides of the slots 122. The base plate 121 can be substantially flat or planar. Although shown as being ‘L’ shaped, angled, or rectangular with a corner portion cut out, the base plate 121 can be rectangular, circular, or any other suitable shape. The corner base plate 121 is cut out or missing so that components of the clamp assembly 130 can access about the middle of a component stack located on the alignment assembly 121. The alignment assembly 121 can be mounted or located on the arm assembly 110 at an angle other than horizontal such that gravity can be used to help locate glass sheets and spacer components.

[0033] FIG. 4 is a rear perspective view of the alignment assembly 120. FIG. 4 shows that each of the shafts 123 is retained in a slot 122 of the base plate 121 by a flange mounted shaft support 125, which is described in more detail below.

[0034] FIG. 5 is a front view of the alignment assembly 120 showing the base plate 121 and shafts 123 mounted in slots 122 via shaft supports 125 seen through the slots 122 and mounting slots 124. The shaft supports 125 can be mounted to the base plate 121 using hardware or fasteners fed through the mounting slots 124. Hardware used to mount the shaft supports 125 to the base plate 121 via the mounting slots 124 is omitted for clarity.

[0035] The size of the base plate 121 and the number and location of the slots 122 can be configured for stacking a particular size of work pieces or glass sheets or can be configured to more flexibly be used for several different sizes of glass sheets. As shown, the base plate 121 can include six slots 122 each with associated mounting slots 124 and a shaft 123 located in each of the slots 122. Although six slots 122 are shown, any suitable number is possible and not all of the slots 122 need to be populated with a shaft 123. The base plate 121 can be made of aluminum or any other suitable material.

[0036] The base plate 121 and shafts 123 in slots 122 provide datums for stack alignment. As configured in FIG. 5, shafts 123 with darker tops (as a visual indicator) can be used to align glass sheets 710 in a stack and shafts 123 with white tops can provide the datums for the other stack components. FIG. 5 shows that there is an intentional dimensional offset between the darker-topped shafts 123 and the white-topped shafts 123. The horizontal offset is shown as “X” and the vertical offset is shown as “Y”, which can be the same or different dimension. A glass sheet 710 with two sides at 90 degrees can be placed in the alignment assembly 120 such that edges of the glass sheet 710 contact shafts 123 with darker tops and cannot contact shafts 123 with white tops because these shafts are offset to the outside of the datums set by the shafts 123 with the darker tops.

[0037] The offset is desired so that edges of the glass sheets 710 in the stack can be exposed and aligned to each other for batch processing while edges of structures used to hold the stack together and protective spacers between glass sheets can be located out of the way. The offsets in both directions can be customized depending on the application by adjusting the relative position of shaft supports 125 holding the shafts 123 in the slots 122 and locking them into place via fastening hardware through the mounting slots 124.

[0038] To achieve the desired offset between the glass sheets and the other components in the stack, a series of different cylindrical locators can be utilized in conjunction with the shaft positions. The locators are deigned to have a close running slip fit over the shafts 123. The radius of the locators along with the X and Y dimensions from FIG. 5, controls the offset of the contacting stack component relative to the edges of the glass sheets. The heights of the locators are determined by the thickness of the contacting stack component and the glass sheet thickness. This is described with respect to FIGS. 6 and 7.

[0039] FIG. 6 is a view of the alignment assembly 120 and a component stack including the bottom plate 140, the glass stack GS, and the top plate assembly 1400 located on the base plate 121. As discussed below, the top plate assembly 1400 can include a padding plate 160, a manifold 170, and a top plate 150. The glass stack GS can be made of alternating layers of glass sheets 710 and spacers 700, seen in Detail A of FIG. 7. As shown in FIG. 6, the alignment assembly 120 is oriented at an angle other than horizontal such that gravity assists in locating corners of the stacking components to a lower corner of the alignment assembly 120 and helps to keep the stack components referenced against the shafts 123 and locators 1100, 1200. FIG. 6 also shows the locators 1100 and 1200 fit over some shafts 123 and used to locate and space stacking components relative to each other. The locators 1100 and 1200 are shown as fit over shafts 123 that are not used to align glass sheets. Two shafts are indicated as 123A and 123B to assist in understanding the orientation of the view in FIG. 7. [0040] FIG. 7 is a side sectional view of the alignment assembly 120 shown in FIG. 6 and includes an enlarged Detail A. The side view of FIG. 7 shows the base plate 121, shafts 123, and a shaft support 125. FIG. 7 also shows stacked components including the bottom plate 140 and glass stack GS and their relative orientations provided by location of the shafts 123A and 123B and locators 1100 and 1200. Other stacked components shown in FIG. 6 are omitted for clarity. Detail A in FIG. 7 shows that shaft 123A determines the location of the edges of the glass sheets 710. Shaft 123B and locator 1100 determines the edge location and offset of the bottom plate 140 from the aligned edges of the glass sheets 710. Shaft 123B and locators 1200 determines the edge locations and offset of the spacers 700 from the aligned edges of the glass sheets 710. Height dimensions of the locator 1100 are determined by the thickness of the bottom plate 140. Height dimensions of the locator 1200 are determined by the thickness of the spacers 700 and the glass sheets 710.

[0041] Optionally, a prefabricated reference plate with geometry including predetermined X and Y offsets can be used to orient the position of the shafts 123 to the base plate 121. The reference plate can be set into position relative to the base plate 121 and shafts 123 can be moved to contact edges of the reference plate and then securely fastened into position. Optionally, a glass sheet 710 can be used to locate shafts 123 designated to align the glass sheets 710. A glass sheet 710 can be set into position relative to the base plate 121 and shafts 123 can be moved to contact edges of the glass sheet 710 and then securely fastened into position. A spacer 700 can be used with a glass sheet 710 to locate shafts 123 to be fit with a locator 1200.

[0042] To build the component stack after the shafts 123 have been arranged and fastened into position with the desired offset, the locators 1100 can be fit over certain offset shafts, the bottom plate 140 can be placed into position contacting the base plate 121 and the locators 1100, a locator 1200 can be fit over the locators 1100, a spacer 700 can be placed into position contacting the bottom plate 140 and the locators 1200, a glass sheet 710 can be placed into position contacting the spacer 700 and shafts 123 that are not offset, another locator 1200 can be fit over the locators 1100, another spacer 700 can be placed into position contacting the glass sheet 710 and the locators 1200, another glass sheet can be placed into position contacting the spacer 700 and shafts 123 that are not offset, and so on. The action of fitting locators 1200, placing spacers 700, and placing glass sheets 710 can be repeated until the glass stack GS is at a desired thickness or includes a desired number of glass sheets 710. [0043] FIG. 8 is an example of a shaft 123. As shown, the shaft 123 can be solid and substantially cylindrically shaped. Optionally, at least one end of the shaft 123 can be threaded. Optionally, the shaft 123 can be hollow or of any geometrically suitable cross section. The shaft 123 can be made of aluminum, plastic, composite, foam, or any other suitable material.

[0044] FIGS. 9A and 9B are different perspective views of an example shaft support 125. FIG. 9B shows that the shaft support 125 can include a flat surface 1251 to contact with a flat surface of the base plate 121 of the alignment assembly 121. The shaft support 125 can also include an opening 1252 that can be centrally located and used to secure a shaft 123. A diameter of the opening 1252 can be slightly larger than a diameter of a shaft 123 such that one end of the shaft 123 can be inserted into the opening 1252 and the diameter of the opening 1252 can be closed around the shaft 123 using a tightening or clamping mechanism 1253. As shown, once an end of a cylindrical shaft 123 has been inserted into the opening 1252, a tool can be used to rotate an end 1254 of the clamping mechanism 1253 to close the opening 1252 around the shaft and secure the shaft 123 to the shaft support 125. In another aspect, the opening 1252 can be threaded and receive an end of a shaft 123 having corresponding threads. The shaft support 125 can also include mounting holes 1255. As shown, there can be two mounting holes 1255 with one each located on either side of the opening 1252. The center-to-center distance of the opening 1252 to the mounting holes 1255 can be the same as that between the slots 122 and mounting slots 124 shown in FIG. 3. The mounting holes 1255 can be arranged to accept fasteners used to mount the shaft support 125 to the base plate 121 of the alignment assembly 120 illustrated in FIGS. 4 and 5. Optionally, the mounting holes 1255 can be threaded.

[0045] FIGS. 10-12 illustrate exemplary locators 1000, 1100, and 1200, respectively. The locators 1000, 1100, and 1200 can be generally circular and symmetric about a central axis through respective openings 1010, 1110, and 1210 used to fit the locators 1000, 1100, and 1200 over a circular shaft 123. The locators 1000, 1100, and 1200 can each include two portions with different outer diameters each with a thickness along the central axis. Locators 1000 and 1100 with relatively thick portions can include a threaded hole 1120 and 1220, respectively, that can be configured to receive a set screw used to lock the locators 1000 and 1100 to a shaft 123. The outer diameters and thicknesses of the locators 1000, 1100, and 1200 are designed to be used with and provide an offset dimension from a shaft 123 to locate relative positions of components in a stack, as discussed with respect to FIGS. 6 and 7. Locators configured such as 1000 and 1100 can be used with bottom and top plates 140, 150 and a locator configured such as 1200 can be used with spacers 700 between glass sheets 710. [0046] FIGS. 13A and 13B are rear and front views of the bottom plate 140, respectively. As shown the bottom plate 140 can be substantially planar shaped. The rear surface of the bottom plate 140 can include a centrally located recess or depression to fit with a portion of the clamp assembly 130, as discussed below. The bottom plate 140 can also include other holes or recesses in which to mount tooling or fixtures used during subsequent processing of the glass stack GS. The x-y size of the bottom plate 140 is configured to be slightly smaller than the x-y size of the glass sheets 710. The bottom plate 140 can be any suitable thickness and be made of any suitable rigid material that is compatible with clamping forces provided by the clamp assembly 130.

[0047] FIGS. 14A and 14B are rear and front views of the top plate assembly 1400, respectively. As previously mentioned, the top plate assembly 1400 can include a padding plate 160, a manifold 170, and a top plate 150 that can be coupled together. The top plate assembly 1400 can be used to apply an even pressure through the glass stack GS to the bottom plate 140 to hold the glass sheets 710 and the spacers 700 together for edge processing. The force can be applied to the glass stack GS by pneumatic pressure through the top plate assembly 1400.

[0048] As shown, fasteners such as nuts and bolts can be used to hold the padding plate 160, the manifold 170, and the top plate 150 together via holes through these components. The padding plate 160 can be one piece or several pieces that define a frame around a periphery of the top plate assembly 1400 and used to directly contact with and provide an air seal to the glass stack GS. The padding plate 160 can be made of aluminum or another suitable material that actuate when pressure is applied to the top plate assembly 1400.

[0049] The top plate 150 can be made from a rigid material and include a pneumatic coupling 151 used to connect a forced air or another suitable gas. The top plate 150 can also include a centrally located recess 152 or depression used to fit and locate a clamped ball as part of the clamp assembly 130. The manifold plate 170 can include channels and diaphragms used to route air and distribute and balance air pressure to the glass stack GS. The components of the top plate assembly 1400 facilitate the pressure averaging to provide a uniform clamping force across the padding plate(s) 160. The top plate 150 can also include plugs that are inserted into holes in the top plate 150. One or all of the plugs can be loosened to relieve the clamping pressure for disassembly of the glass stack GS.

[0050] FIGS. 15A and 15B are perspective views of the clamp assembly 130. The clamp assembly 130 can include a substantially rectangularly shaped frame 131 with at least one handle 135. The clamp assembly 130 can also include a knob 132 used to rotate a threaded shaft 133 with a cup 134 A at one end through a side of the frame 131. The frame 131 can also include another cup 134B on another side of the frame that opposes the cup 134A at the end of the threaded shaft 133. The cups 134A and 134B can be made of brass or any other suitable material.

[0051] FIGS. 16A and 16B are perspective views of the clamp assembly 130 securing stacked components. In use, the stacked components are assembled in order on the alignment assembly 120 as shown in FIG. 6. Once all the stacked layers are in place, the top plate assembly 1400 is positioned on top of the glass stack GS using similar locators as the bottom plate 140. As shown, the order of stacked components can include the bottom plate 140, the glass stack GS, and top plate assembly 1400. The clamp assembly 130 is fit over the stacked components and a ball bearing, metal ball, or ball made of another suitable material can be seated in each of the cups 134A and 134B prior to rotating the knob 132 and tightening the threaded shaft 133 through the frame 131. This action holds the stacked components into place on the alignment assembly 120. In this example, a clamping force is applied via pneumatic pressure through pneumatic coupling 151 of the top plate assembly 1400. The clamp assembly 130 resists the pneumatic force. In an aspect, the pneumatic pressure can be about 30 psi. In another aspect, the pneumatic pressure can be between about 25 psi to about 35 psi.

[0052] The balls seated in the cups 134A and 134B provide points of contact between the clamp assembly 130 and bottom plate 140 and top plate assembly 1400. This permits 360- degree rotation of the stacked components within the clamp assembly 130. The entire stack components secured by the clamp assembly 130 can then be removed from the alignment assembly 120 and stored or installed on any processing fixture that has been made to interface with the stacked components. This, along with the 360-degree rotation of the component stack, facilitates processing on all four exposed edges of the glass stack GS without having to re-build the glass stack GS.

[0053] It should be understood that the foregoing description is only illustrative of the present disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the present disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications, and variances that fall within the scope of the appended claims.