Mounting device

Abstract

Fastening device for holding a workpiece (10), comprising: Clamps (34), each clamp (34) being configured to engage with a corresponding pull rod (14, 15, 16, 17) attached to the workpiece (10); Arrangement pins (30) each having a convex surface facing the workpiece (10), wherein each arrangement pin (30) is configured to engage with its convex surface a concave surface of an associated arrangement pin (12, 13) attached to the workpiece (10); Support surfaces (32), each on which a part support detector (50) is located; and Actuators, each actuator being configured to move one of the clamps (34) in a direction parallel to the longitudinal axis of the pull rods (14, 15, 16, 17) to alternately pull the workpiece (10) into contact with the support surfaces (32) and release the engagement between the pull rod (14, 15, 16, 17) and the clamp (34) so ​​that the fastening arrangement can release the workpiece (10).

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to fastenings for holding a workpiece while manufacturing operations are carried out on the workpiece, and in particular to a fastening device for holding a workpiece.

[0002] DE 43 07 342 A1 describes, for example, a clamping device by means of which a workpiece carrier, carrying a workpiece to be machined, can be clamped to a machine tool. The clamping device has a base and a workpiece carrier that can be clamped to it. Alignment elements are arranged on the base and work together in pairs to align the workpiece carrier in three mutually perpendicular coordinate axes and at right angles to the base. Several clamping elements, with their clamping force, hold the tool carrier in the position on the base determined by the alignment elements. Each clamping element has a chuck on the base and a clamping pin on the tool carrier. Opposing stop surfaces are provided as alignment elements for determining the position in a coordinate axis parallel to the line of action of the clamping force.To make the workpiece carrier as simple and cost-effective as possible, it has a continuously flat surface on the side facing the base when clamped. This surface forms the stop surfaces in some areas, and the alignment elements for defining the coordinate axes and the clamping pins are attached to this surface.

[0003] Further details of the state of the art can be found in publications DD 85 699 A1, CN 201136101 Y and US 3 565 416 A.

[0004] Holding a workpiece and positioning it precisely during machining operations involving multiple processes presents a challenge. This is especially true when tools used to machine a complex-shaped workpiece require access from multiple sides. For example, a cylinder head for an internal combustion engine may require access from several sides for a variety of different operations.

[0005] Attempts have been made to machine these types of workpieces by attaching adapter plates to the workpiece and then supporting the adapter plate. However, these processes can be expensive and may require the design of extensive part features on the workpiece, such as on a cylinder head.

[0006] The invention is based on the objective of being able to reliably hold workpieces that do not have exactly the same dimensions before processing for machining purposes. SUMMARY OF THE INVENTION

[0007] This problem is solved by a fastening device for holding a workpiece having the features of claim 1.

[0008] One advantage of this embodiment is that the clamping device provides a machining location not present on the exposed surface, yet still produces a machined part that is essentially machined from the desired exposed surface. The clamping device allows access to five surfaces of a cylinder head for machining operations to be performed on the head. The number of clamping positions can be minimized, resulting in fewer loading and unloading operations of the component and therefore fewer machining operations. Access to five surfaces of a cylinder head can also allow for a reduced tool length for the tools used to machine the head and can improve tolerances in the finished parts. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 and Fig. Figure 2 shows a top view or a side view of a cylinder head for an internal combustion engine, showing tie rods and arrangement pins engaged with the cylinder head; Fig. Figure 3 is a side view of a fastening arrangement that supports the cylinder head and includes clamping cartridges that engage with the tie rods; Fig. Figure 4 is a perspective view of the fastening device; and Fig. Figure 5 is a side view of a clamping cartridge engaged with one of the pull rods. DETAILED DESCRIPTION

[0009] In the Fig. 1 and Fig. 2 includes a cylinder head 10 for an internal combustion engine (not shown), arrangement pins 12, 13 which are formed with concave surfaces, and threaded bores for receiving tie rods 14, 15, 16, 17.

[0010] A threaded shank 18 of each drawbar 14-17 engages with the threaded bores formed in the cylinder head 10. The head 20 of each drawbar extends outward from the outlet surface 22 of the cylinder head 10 and is dimensioned and shaped to be received and selectively held in a fastening arrangement. Each drawbar 14-17 comprises a cylindrical shank located between the threaded shank 18 and the head 10, the cylindrical shank extending parallel to the cylindrical shanks of the other drawbars and perpendicular to the outlet surface 22.

[0011] The Fig. 3 and Fig. Figure 4 shows a fastening arrangement 24 comprising an upper quick-connect fastening device (QC fastening device) 26 having four clamping holders 28, each holder engaging with the head 20 of each tie rod 14-17, an arrangement pin 30 having a convex surface facing the cylinder head to engage with the concave arrangement pin 12 on the outlet surface 22, and an arrangement pin 30 having a convex surface facing the cylinder head to engage with the concave arrangement pin 13 on the outlet surface 22.

[0012] How Fig. As shown in Figure 5, each clamping holder 28 comprises a support surface 32 and a clamping device 34, which is located in a cylinder 36 and is attached to a piston 38, which is also located in the cylinder. Fig. In position 5, the clamping device 34 is located at the upper end of its path of movement, where a recess 40, formed in a rod 42 connected to the piston 38, is in contact with the lower surface of a stop 44. When the piston 38 is actuated downwards to pull the cylinder head 10 into contact with the support surface 32, the axially opposite surface of the recess 40 comes into contact with the upper surface of the stop 44. The pressure exerted on each clamping holder 28 actuates the piston 38 upwards and downwards through a plate 46.

[0013] Each clamping device 34 also includes a pull-rod holder 48 or a clamping bar that engages with the head 20 of one of the pull rods 14-17. The pull-rod holders 48 and the support surfaces 32 may also have a part support detector 50 that detects when the cylinder head 10 is correctly positioned relative to the upper mounting device 26. The clamping holder 28 may include an air release for releasing the clamping of the holder. Each pull-rod holder includes a recess 52 for receiving the head 20 of a pull rod 14-17 and a retaining lip 54 that engages with the head 20 of the pull rod located in the recess 52. The pull-rod holder 48 may have an internal passage that can be used to blow debris out of the recess 52.

[0014] The upper mounting device 26 also includes arrangement rings 56, 58 for positioning and securing the upper mounting device to the lower mounting device 28. The mounting devices 26, 28 may also have quick couplers that create a connection between the two mounting devices to allow the flow of oil, coolant, and air between them. The lower mounting device 28 may have Pascal clamping devices located near each of its corners and pre-arrangement devices to ensure proper arrangement and fastening. The lower mounting device 28 may be mounted on a five-axis linear motor machine, enabling five-axis machining of the cylinder head 10.

[0015] In addition, an RFID label can be mounted on the cylinder head 10 to enable the identification of each cylinder head when it is loaded into the mounting arrangement.

[0016] To attach the cylinder block 10 to the mounting assembly 24, the tie rods 14-17 are oriented so that they extend from the cylinder block to the upper mounting device 26, as shown in Fig.Figure 3 shows that the pull rods 14-17 are located near the openings to the recesses 52 in the pull rod holders 48. Each of the pull rods 14-17 is received in one of the recesses 52. The clamping device 34 of each clamping holder 28 is actuated to cause the retaining lip 54 to engage with the engagement head 40 of the corresponding pull rod 14-17 and pull the pull rod towards the upper mounting device 24 until the part support detectors 50 on the support surfaces 32 detect that each pull rod 14-17 is positioned as desired. The cylinder head 10 is then held in the desired position for various operations, such as machining to be performed on the cylinder head 10. Finally, the clamping devices 34 are actuated to release the pull rods 14-17 from the mounting device 24. The tie rods 14-17 can then be removed from the cylinder head 10.

[0017] Mounting the cylinder head 10 on the mounting assembly 24 provides access to five surfaces of the head 10. A partially finished cover surface and the head / block dowel can be produced as raw end features in the same mounting. The final machining can be performed using the same concept. The cover surface and the dowel are finished simultaneously with the execution of the final machining of all critical features of the head 10.

[0018] Although this type of fastening arrangement is particularly well suited for use with a cylinder head 10, it can also be applied to other types of prismatic surfaces when access to multiple surfaces for machining is desired.

Claims

[1] A fastening device for holding a workpiece (10), comprising: Clamps (34), each clamp (34) configured to engage a corresponding drawbar (14, 15, 16, 17) attached to the workpiece (10); Locating pins (30) each having a convex surface facing the workpiece (10), each locating pin (30) being configured to engage with its convex surface a concave surface of an associated locating pin (12, 13) secured to the workpiece (10); Support surfaces (32), each of which has a part support detector (50) located thereon; and Actuators, each actuator being configured to move one of the clamps (34) in a direction parallel to the longitudinal axis of the drawbars (14, 15, 16, 17) to alternately pull the workpiece (10) into contact with the support surfaces (32) and release the engagement between the drawbar (14, 15, 16, 17) and the clamp (34) so ​​that the fastening assembly can release the workpiece (10). [2] Fastening device according to claim 1, wherein each clamp (34) further comprises a tie rod holder (48) formed with a recess (52) capable of receiving a head (20) of the tie rod (14, 15, 16, 17). [3] Fastening device according to claim 2, further comprising: a retaining lip (54) which can overlap and engage with a head (20) of the pull rod (14, 15, 16, 17); a cylinder (36); and a piston (38) which is movable in the cylinder (36) and is fastened to the tie rod holder (48). [4] Fastening device according to claim 3, further comprising: a source of pressurized fluid connected to the cylinder (36) for moving the clamp (34) in opposite directions along the length of the cylinder (36). [5] Fastening device according to claim 3, wherein: the piston (38) is formed with a second recess (40) and each clamp (34) has a stop (44) extending into the recess (40) and limiting the displacement of the piston (38) due to contact between the stop (44) and the second recess (40).

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