WO2007085049A1

WO2007085049A1 - Jig for locating holding and repositioning a surfboard or workpiece during machine shaping

Info

Publication number: WO2007085049A1
Application number: PCT/AU2007/000067
Authority: WO
Inventors: Samuel Thomas Pickering; Mark Joseph Pivac
Original assignee: Plastertech Australia Pty Ltd
Priority date: 2006-01-25
Filing date: 2007-01-25
Publication date: 2007-08-02
Also published as: WO2007085050A1

Abstract

A pneumatically controlled actuator that extends until contact is made with the work piece and is then locked into position with negligible run on or retraction. A jig which has a first work holding position with said jig able to be rotated through part of a revolution.

Description

"Jig for Locating Holding and Repositioning a Surfboard or Workpiece During Machine Shaping"

The invetniton is described in the following statement:-

Jig for Locating Holding and Repositioning a Surfboard or Workpiece During Machine Shaping

Field of the Invention

The present invention relates to a automated clamping mechanism within a jig to enable a work piece to be accurately removed from the work holding fixture on a machine, turned over and be accurately replaced on the work holding fixture when it is being formed by a computer controlled or manual copy shaping machine. In particular the invention relates to the manufacture or shaping of surfboards, sailboards, wakeboards, kite boards, snowboards and other similarly shaped articles but is also applicable to any object that needs to be held and turned over accurately during a shaping or processing operation.

Background of the Invention

It is known to use various types of machine to automatically shape or copy a surfboard. Such machines include computer controlled three and five axis routers, manual copy machines and a computer controlled shaping machine known as the Cybernetic shaping machine.

Known means and machinery allows the top or deck, and the bottom of a surfboard to be shaped individually very accurately. The overall finish of a surfboard requires that the shaping done on the top of the board match exactly the shaping done on the bottom. For access requirements it is necessary to either move fixtures used to locate the surfboard or remove the surfboard from the machine, turn it over and then accurately locate it back onto the machine so the remaining side can be shaped. A major problem overcome by the present invention is that surfboard blanks have an inbuilt stress in them which can be partly relieved by machining just one side. If after machining just one side of the blank it is released from the holding mechanism the blank will distort or change shape from its original shape. Then when the second side is machined it will not match up with the first side machining. The present invention overcomes this problem by maintaining the blank in its original undistorted shape by keeping it firmly held at all times throughout machining of both sides and during setup changes from one side to the other.

The present invention was developed with a view to providing a means of accurately machining all surfaces of a surfboard or similarly shaped object whilst maintaining a rigid hold on the object at all times during the machining process.

Summary of the Invention

A surfboard-shaping machine with a work holding table has a jig connected to the base of this table. The jig has a clamping table that can pivot 180 degrees.

To position a board the clamping mechanism of the jig is brought into engagement with the surfboard and held with vacuum suction cups. This is achieved by positioning the surfboard on three locating fixed pads. Once in alignment the actuators automatically retract their outer rubber sealing rims to leave proud the locator foot of each cup. Each actuator mechanism then extends with adjustable force until positive contact with the surfboard blank has been achieved. Said actuators then lock into position with negligible run on. All rubber-sealing rims are then released and a vacuum is applied to all suction cups, securing the surfboard to the jig. The surfboard deck or top is then shaped.

The jig is then rotated 180 degrees, positioning the surfboard upside down or bottom up. Before releasing the surfboard a second series of actuators automatically extend to meet the top of the surfboard in the same manner as described for the bottom. Once secured the first set of said actuators are released and the jig rotated back 180 degrees. The surfboard bottom is then shaped. . During this process the surfboard has been rotated by 180 degrees relative to the clamping table of the shaping machine.

Brief Description of the Drawings

Figure 1 is a schematic exploded representation of the said actuator.

Figure 2 is a cross section of the said actuator.

Figure 3 is a cross section of the pad in its retracted position. Figure 4 is an isometric drawing of a holding and turn over jig.

Figure 5 is an end view of a holding and turnover jig in a first position with a work piece clamped to it in a first clamping position.

Figure 6 is an end view of a holding and turnover jig in a second position with a work piece clamped to it.

Figure 7 is an end view of a holding and turnover jig in a third position with a work piece clamped to it being transferred to a second clamping position.

Detailed Description of Preferred Embodiments

With reference to the accompanying drawings and in particular Figure 1 and Figure 2. Figure 1 shows a simple first embodiment of the actuator 1. Provided on the mechanism is first rectangular housing 2 and second rectangular housing 3. . On the lower end of the second rectangular housing 3 there is a lower cap 4. Separating housing 2 and housing 3 is a middle cap 5. On top of the first rectangular housing is a combined bearing and end cap 6. The middle cap 5 and top cap 6 have a cylindrical hole allowing the shaft 7 to slide freely. Housing 3 acts as an air cylinder with varying pressure being applied to facilitate extension of the shaft 7.

Referring in particular to the suction cup 8 which includes a sealing rim 9. The sealing rim 9 is made of a compliant material such as foam rubber, rubber or silicone or polyurethane rubber. The suction cup is provided with a recess 10 allowing a vacuum to be applied and in-turn retracting the sealing rim 9 leaving proud the locator foot 11. Referring to Figure 1 the shaft 7 extends until the locator foot 11 comes in contact with the surfboard (not shown). To lock the shaft in position air is supplied to a tube 12, expanding the tube 12 between a backing plate 13 and a clamping arm 14. The clamping arm 14 pivots about an axis 15 applying pressure to the shaft 7 locking it in position. It has been found beneficial to coat the top of the locator foot 11 with non slip material 16. The non slip material 16 may be rubber if metal work pieces (not shown) are to be clamped or abrasive sand paper when foam work pieces such as surfboards (not shown) are to be clamped.

The suction cup 8 is fitted to a commercially available spherical bearing 17. This assembly of suction cup 8 and spherical bearing 17 is retained on the shaft by press fitting and or adhesive (not shown). Those skilled in the arts will appreciate that mechanical fasteners such as screws or bolts could be used to spimplify assembly but at the disadvantage of being less compact.

The actuator 1 can be mounted to a jig (not shown) with tapped mounting holes 18. The actuator 1 is assembled and held together via a plurality of tie rods 19, two of which are illustrated in Figure 2. The tie rods are clamped with nuts 20 and washers 21. Normally 4 tie rods 19 would be employed. Obviously either the top cap 6 or bottom cap 4 or middle cap 5 could have tapped holes and then long bolts rather than tie rods could be utilised to hold the actuator 1 together without departing from the inventive concepts described here in.

The flexible tube 12 is fitted into a fitting 22 that allows an air line 23 to be connected to it. The flexible tube 12 can be flattened for example by the application of heat so that it can be more easily expanded by the compressed air not shown. An alternative embodiment replaces the flattened tube 12 with a pneumatic ram. Those skilled in the art will appreciate that a solenoid or hydraulic ram could also be used to impart the force required to cause the clamping arm 14 to lock against the shaft 7.

The lower chamber 24 is formed by the lower housing 3 and the lower cap 4 and middle cap 5. The lower housing 3 is provided with a fitting 26 that is connected to an air line 25. The air line 25 can then be pressurised by normal industrial means (not shown) to in turn pressurise the lower chamber 24.

Figure 2 shows the sealing rim 9 in the position it assumes when clamping a workpiece 27. The work piece 27 and sealing rim 9 form a chamber 28 that is connected to a fitting 29 and vacuum line 30. Application of vacuum on the vacuum line 30 evacuates the chamber 28 thereby allowing atmospheric pressure acting on the work piece 27 to force the work piece 27 against the locating foot 11. Thus the work piece 27 is effectively held to the actuator 1.

Figure 3 shows a cross section of the sealing rim 9 in a retracted position against the pad 8. This retracted position allows a workpiece 27 to be positioned against the locator foot 11 without needing to push against a sealing lip. This prevents distortion of the workpiece 27 which if made of a soft material such as surfboard foam would otherwise experience significant distortion when pushed against many vacuum pads on a holding jig (not shown in Figure 3). The chamber 31 is formed by the recess 10 in the pad 8 and the sealing lip 9. The chamber 31 is connected to a fitting 32 that is in turn connected to a vacuum tube 33. The sealing lip 9 is forced back by atmospheric pressure acting on it when the chamber 31 is evacuated by applying a vacuum to the vacuum tube 33 by normal industrial means (not shown).

Those skilled in the art of material handling and mechanics will appreciate that various means of locking the shaft 7 relative to the housing 2 and housing 3 may be embodied by using various types of force application such as pneumatic or hydraulic cylinders. All such variations are deemed to be within the scope of the present invention. The described embodiment using a flexible tube 12 has the advantage of compactness and simplicity with few moving parts.

Figure 4 shows an isometric view of a holding and turnover jig 34. Figures 5, 6 and 7 show an end view of the holding and turnover jig 34.The holding and turnover jig 34 is designed to be fitted to the table of a shaping machine or copy machine (not shown) such as a 5 axis CNC (computer numerically controlled) router.

The turnover jig 34 is fitted with a plurality of the previously described actuators 1. The actuators 1 are arranged in two groups that form a first clamping position 35 and a second clamping position 36.

The holding and turnover jig 34 has a fixed frame 37 and moving frame 38. The fixed frame 37 is clamped to the shaping or copy machine (not shown) by suitable means such as bolting, clamping or vacuum hold down (not shown).

The moving frame 38 is fitted to a first bearing 39 and a second bearing 39' allowing it to rotate about the axis 40.

Figure 5 shows the moving frame 38 in a first position resting against the fixed frame 37.

Figure 5 shows a surfboard work piece 27 clamped in a working position 35. Figure 6 shows the moving frame 38 in a transition position. Figure 7 shows the moving frame 38 in a transfer position.

The moving frame 38 may be rotated about the bearing 39 manually or by a rotary actuator (not shown) or by using the machine (not shown) to move it. A shaping machine (not shown) may rotate the moving frame by engaging a spigot on the head of the shaping machine into a socket on the moving frame 38, thereby allowing the head of the shaping machine to pick up and rotate the moving frame 38 about the bearing 39 and axis 40.

Referring to Figure 4 the actuators 1 are clamped to frames 41, 42, 43, 44, 45, and 46. Obviously the number of frames 41 to 46 may be varied to suit the workpiece. Also the number of actuators 1 on each frame 41 to 46 may also be varied to suit the workpiece.

Figure 5 shows a frame 41 fitted with two actuators 1. The frame 41 is provided with a sliding bearing 47 and a clamping bar 48. The frame 38 is fitted with a rail 49 that supports the bearing 47 and thus the frame 41 fitted with actuators 1. The clamping bar 48 may be clamped tight with a bolt 49 fitted with a handle 50, the bolt engages in a fixed nut 51 attached to the clamping bar 48. Each frame 41 to 46 is fitted with a similar clamping mechanism to that described.

Figure 7 shows the moving frame 38 in a transfer position. This position allows the work piece to be clamped by the actuators 52 mounted to the fixed frame 37 while it is also held by the actuators 1 mounted to the moving frame 38. Note that the actuators 52 are similar to or identical to the actuators 1 previously described. In the transfer position the frame 38 is supported by a stop 53 that mates against a fixed stop 54 mounted to a leg 55 fitted to the fixed frame 37. After the actuators 52 have clamped the board in the second working position 36 the first actuators 1 can be released. The moving frame 38 can then be rotated back to the first working position 35 whilst leaving the work piece 27 in the second working position 36.

Claims

1. A pneumatically controlled actuator that extends until contact is made with the work piece and is then locked into position with negligible run on or retraction.

2. A suction cup with retracting outer sealing rim enabling positive contact with the work piece without imparting undue force causing distortion.

3. A suction cup with a central ridgid locating face to provide positive contact with the work piece without deflection relative to the ridgid body of the suction cup.

4. A suction cup fitted with a spherical bearing to allow alignment of the suction cup with differently shaped workpieces.

5. A jig which has a first workholding position with said jig able to be rotated through part of a revolution.

6. A jig which has a second workholding position.

7. A jig which has the second workholding position able to receive a part held by the first workholding position.

8. The jig of claims 5 to 7 with a first set of suction cups and actuators according to claims 1 to 4 in the first workholding position that can be moved to clamp a work piece.

9. The jig of claims 5 to 8 with a second set of suction cups and actuators according to claims 1 to 4 in the second workholding position that can be moved to clamp a work piece held in the first workholding position.

10. Any jig incorporating any number of, or combination of, or permutation of claims 1 to 9.