Holding device for a blank

Abstract

The invention relates to a holding device (100) for a blank (200), having a first holding element (101-1, 401-1) for inserting a blank (200); and a second holding element (101-2, 401-2) for clamping the blank (200), which can be locked to the first holding element (101-1, 401-1) by a rotational movement.

Description

Technical Field

[0001] The present invention relates to a holding device for a blank, an auxiliary tool for opening the holding device, and a method for holding a blank. Background Technology

[0002] During routine use of a dental milling machine machining disc-shaped blanks (so-called round blanks), periodic material changes (loading processes) are required. In these processes, the blank is removed from the workpiece fixture and replaced with a new blank. This process varies depending on the dental milling unit and manufacturer. Because these operations require user interaction, they should be as simple and time-efficient as possible.

[0003] To unlock the retaining device currently used for milling the workpiece, the four screws are loosened so that the clamping ring can be removed and the workpiece can be replaced. The clamping ring is then reinserted, and the screws are tightened by hand to the specified torque. This process is time-consuming and requires skill, tools, and attention. Summary of the Invention

[0004] Therefore, the technical objective of this invention is to simplify and accelerate the insertion of the blank into the holding device.

[0005] According to the first aspect, the technical problem is solved by a retaining device for a workpiece, the retaining device comprising: a first retaining element for inserting the workpiece; and a second retaining element for clamping the workpiece, the second retaining element being lockable to the first retaining element by a rotational movement. The retaining device saves time when clamping and releasing the workpiece. Furthermore, the workpiece is stably held between the two retaining elements.

[0006] In a technically advantageous embodiment of the retaining device, the second retaining element is formed of an open or closed ring. This achieves, for example, the technical advantage that the blank can be fixed by rotational movement. The ring can be manufactured in a simple manner.

[0007] In another technically advantageous embodiment of the retaining device, the ring includes a guide portion projecting radially inward or outward. The guide portion may be formed by a pin. The guide portion may project radially in a fan-shaped manner. This achieves, for example, the technical advantage that the guide portion can be supported on a corresponding undercut in the first retaining element.

[0008] In another technically advantageous embodiment of the retaining device, a guide portion is disposed on an arm extending in the axial direction of the second retaining element. This achieves, for example, the technical advantage of being able to clamp the workpiece over a large span.

[0009] In another technically advantageous embodiment of the retaining device, each of the radially projecting guide portions includes a spring portion for generating a clamping force on the workpiece in the direction of the first retaining element. This achieves, for example, the technical advantage that the workpiece can be elastically inserted into the retaining device with a predetermined clamping force.

[0010] In another technically advantageous embodiment of the retaining device, the guide portion extends above the undercut. This also achieves the technical advantage of being able to support the guide portion on the undercut.

[0011] In another technically advantageous embodiment of the retaining device, the first or second retaining element includes a stop element for limiting rotational movement. This achieves technical advantages such as preventing excessive rotation of the second retaining element and pre-determining the correct positioning of the ring by means of the stop element.

[0012] In another technically advantageous embodiment of the retaining device, the first retaining element includes at least one spring element for applying a clamping force on the guide portion of the second retaining element, or the second retaining element includes at least one spring element for applying a clamping force on the guide portion of the first retaining element. This achieves, for example, the technical advantage that the workpiece can be securely clamped between the retaining elements.

[0013] In another technically advantageous embodiment of the retaining device, the spring element is formed of a leaf spring. This has the technical advantage of making the spring element easy to manufacture.

[0014] In another technically advantageous embodiment of the retaining device, the first or second retaining element includes at least one recess for guiding the guide portion through. This achieves, for example, the technical advantage that the guide portion can be guided to opposite sides of the opposing retaining elements and that the retaining elements can be interlocked and secured.

[0015] In another technically advantageous embodiment of the retaining device, the leaf spring is V-shaped. This achieves, for example, the technical advantage of generating a high clamping force for clamping the workpiece.

[0016] In another technically advantageous embodiment of the retaining device, one side of the V-shaped leaf spring rests against the first retaining element. This achieves, for example, the technical advantage of good force transmission between the retaining elements.

[0017] In another technically advantageous embodiment of the retaining device, the spring element is disposed on the side of the first retaining element opposite to the second retaining element. This achieves, for example, the technical advantage that the retaining element surrounds the blank and avoids damage.

[0018] In another technically advantageous embodiment of the retaining device, the first retaining element includes an undercut for a spring portion that supports the second retaining element in the axial direction. This provides, for example, the technical advantage of achieving a good fastening of the first and second retaining elements.

[0019] In another technically advantageous embodiment of the retaining device, the undercut is positioned around the workpiece socket. This achieves, for example, the technical advantage that a uniformly distributed force can be applied to the workpiece.

[0020] In another technically advantageous embodiment of the retaining device, the first retaining element includes a ball thrust member, a spring and a groove system, or an adapter for engagement in the blank. This achieves, for example, the technical advantage that necessary adjustments and positioning can be made in a simple manner.

[0021] In another technically advantageous embodiment of the retaining device, the first retaining element includes a locking element for locking the second retaining element in the closed position. This provides, for example, the technical advantage of preventing accidental release or opening of the retaining device.

[0022] In another technically advantageous embodiment of the retaining device, the first retaining element and / or the second retaining element are formed of a glass fiber reinforced material. The retaining device may then include a radio frequency identification (RFID) chip. This provides the technical advantage that radio waves can pass through the retaining device. Nevertheless, the retaining element exhibits a high level of stability.

[0023] According to the second aspect, this technical objective is achieved by an auxiliary tool for opening the retaining device, the tool comprising at least one engaging element for engaging in a hole or groove in the second retaining element. This achieves, for example, the technical advantage that the workpiece can be quickly and with a large clamping force clamped in the retaining device.

[0024] According to the third aspect, this technical objective is achieved by a method for holding a workpiece, the method comprising the steps of: inserting the workpiece into a first holding element; and clamping the workpiece by rotational movement of a second holding element lockable to the first holding element. Thus, the same technical advantage is achieved by the holding device according to the first aspect.

[0025] In a technically advantageous embodiment of the method, a clamping force is generated on the workpiece along the direction of the first retaining element. This achieves, for example, the technical advantage that the workpiece can be reliably clamped in the retaining device.

[0026] In another technically advantageous embodiment of the method, the spring portion of the second retaining element is supported on the underside of the first retaining element, or a radially inward or outwardly projecting guide portion of the first or second retaining element is supported on the spring element of the first or second retaining element. This achieves, for example, the technical advantage that the workpiece can be securely clamped between the retaining elements. Attached Figure Description

[0027] Examples of embodiments of the invention are shown in the accompanying drawings and described in more detail below.

[0028] Figure 1 A composite holding device including a blank, a first holding element, and a second holding element is shown;

[0029] Figure 2 A view of the first retaining element of the retaining device is shown;

[0030] Figure 3 A view of the second retaining element of the retaining device is shown;

[0031] Figure 4 A view of the blank is shown;

[0032] Figure 5 A retaining device with an auxiliary tool for opening the retaining device is shown;

[0033] Figure 6 Another view of the retaining device with a movable latching element is shown;

[0034] Figure 7 The secondary locking mechanism is shown;

[0035] Figure 8 A block diagram of a method for holding a blank is shown;

[0036] Figure 9 This is another embodiment of the holding device;

[0037] Figure 10 This is a view of the second retaining element of the retaining device; and

[0038] Figure 11 This is a view of the first holding element of the holding device. Detailed Implementation

[0039] Figure 1An assembled retaining device 100 is shown, comprising a blank 200 and first and second retaining elements 101-1 and 101-2. The retaining device 100 is used to clamp and retain the blank 200 in a dental milling machine. The retaining device 100 with retaining elements 101-1 and 101-2 forms a quick-clamping system based on the principle of a snap-fit. A dental object, such as a crown or bridge, can be milled from the blank 200 using a dental milling machine.

[0040] The retaining device 100 can be modularly inserted into the gear milling machine as a quick clamping system. However, the retaining device 100 can also be used directly in the gear milling machine, wherein the first retaining element 101-1 is an integral part of the gear milling machine and does not need to be changed.

[0041] Incorrect insertion of the blank 200 can be prevented by correspondingly forming the blank 200 and retaining elements 101-1 and 101-2, for example, by interchangeably swapping the top and bottom surfaces. In the retaining device 100, a clamping force is generated on the blank 200 by means of a ring rotating under its opposite sides. The ring 103 can be formed as a spring ring. This allows the blank 200 to be stably fixed between the retaining elements 101-1 and 101-2. This occurs when interacting with a bayonet-type locking mechanism.

[0042] The retaining device 100 does not require threads for the fastening screws, which are often damaged or loosened during use. Therefore, clamping the blank 200 in the retaining device 100 does not require a torque wrench or fastening screws that may be lost, damaged, or worn. When tightening the fastening screws, the clamping force on the blank 200 no longer depends on the correct use of the torque wrench. Furthermore, the retaining device 100 is compatible with replacement systems.

[0043] Figure 2 A view of the first retaining element 101-1 of the retaining device 100 is shown. The retaining element 101-1 is annular. A blank 200 is inserted into and received inside the retaining element 101-1. For this purpose, the first retaining element 101-1 includes a cylindrical workpiece socket 113 for inserting the disc-shaped blank 200.

[0044] Insert the blank 200 into the retaining element 101-1 with the correct side facing upwards. The ball thrust member 115 protrudes into the interior of the retaining device 100, and the blank 200 engages with the ball thrust member 115. The ball thrust member 115 can engage in a matching groove or hole 201 on the outside of the blank 200, thereby positioning the blank 200. To do this, the user rotates the blank in the retaining element 101-1 until the ball thrust member 115 engages in the groove of the blank 200. An audible engagement sound is produced when the blank 200 is rotated to the correct position.

[0045] When a blank 200 without the hole or groove 201 is used, the thrust member 115 springs into place and is accommodated in the first retaining element 101-1. This ensures compatibility with other blanks. Suitable adapters can be used for other blanks 200.

[0046] The user now places the ring 103 in the retaining element 101-1. Several bag-shaped undercuts 109 are disposed on the upper side of the retaining element 101-1. These undercuts 109 may be spring-loaded. The number and shape of the annular undercuts 109 are variable. The undercuts 109 serve to support the ring 103, which serves as a second retaining element 101-2.

[0047] Ring 103 then rotates approximately 45 degrees. o The required clamping force is generated on the blank 200. However, the angle of rotation can usually be selected differently. The clamped blank 200 is now ready for direct use in the dental milling unit in the retaining device 100. Depending on the clamping force, the ring 103 can be manually rotated by hand or with the aid of an auxiliary tool. The retaining device 100 saves several minutes each time the material is changed without having to tighten or loosen the fastening screws.

[0048] Retaining elements 101-1 and 101-2 can be designed for injection molding, making them easily manufactured by means of metal casting or plastic injection molding. Retaining element 101-1 can also be designed as a glass fiber reinforced component. In this case, radio waves from the RFID chip can pass through the component disposed in retaining element 101-1. In this way, retaining device 100 can be tagged by means of an RFID chip or other chip, and the RFID chip can be read by retaining device 100.

[0049] The undercut 109 can also secure the second retaining element 101-2 to the first retaining element 101-1 via a friction connection. For example, the undercut 109 can be elastically mounted and secured together by a lever. In this way, the second retaining element 101-2 can be clamped to the first retaining element 101-1.

[0050] Figure 3 A view of the second retaining element 101-2 of the retaining device 100 is shown. The second retaining element 101-2 is formed by a flat, circular ring 103. Through the ring 103, a clamping force is applied to the blank 200 in the direction of the first retaining element 101-1. If a high clamping force is required, an auxiliary tool can be used to lock and unlock the ring 103.

[0051] Ring 103 includes a radially projecting guide portion 105 extending outward in a star shape. The guide portion 105 forms a pre-bent profile arranged in a circular configuration. By rotation in interaction with the opposing undercut 109, the guide portion 105 is capable of generating a preload between the first retaining element 101-1, the second retaining element 101-2, and the blank 200.

[0052] As spring elements, the guide portions 105 each include spring portions 107 for generating a clamping force on the blank 200 in the direction of the first retaining element 101-1. The spring portions 107 further include bending stop elements 111 for limiting rotational movement. Typically, the spring element can also be formed from another elastic element that applies force to the retaining element 101-1 in the axial direction, such as a coil spring or a ratchet spring. In this way, the blank 200 can be clamped between the retaining elements 101-1 and 101-2.

[0053] For example, if radial grooves are present, ring 103 can have a closed or open design. The variable design of ring 103 in terms of shape, angle, material thickness, and grade means that clamping forces on blank 200 can be accommodated, as different blanks 200 require different clamping forces. Using different rings 103, for example, individual rings 103 made of zirconium or metal, the clamping force on blank 200 can be variably adjusted. Ring 103 can be formed by laser cutting or bending of a metal sheet.

[0054] The ring 103 includes a plurality of holes 119 around its circumference. The holes 119 allow an auxiliary tool to engage to open the ring 103. For this purpose, grooves may also be provided in the ring 103 for the auxiliary tool to engage.

[0055] Figure 4 A view of blank 200 is shown. Blank 200 is circular and disc-shaped. However, other shapes of blank 200 are also generally possible, such as rectangular or hexagonal. Blank 200 includes a groove 201 in which the ball thrust member 115 of the first retaining element 101-1 engages, thereby indicating the unique position of blank 200 within retaining device 100.

[0056] To allow the retaining device 100 to be opened, the guide portion 105 may extend above the undercut 109. In this case, the retaining device 100 can be opened by hand or with the aid of an auxiliary tool 300. The undercut 109, which has an elongated configuration, can be locked by means of the opening ring 103.

[0057] Figure 5A retaining device 100 with an auxiliary tool 300 for opening the retaining device 100 is shown. The auxiliary tool 300 includes a handle 301 by which the auxiliary tool 300 can be manually rotated. A pin 303 is disposed around the auxiliary tool 300, which passes through a hole 119 or groove in a second retaining element 101-1 when the auxiliary tool 300 is placed on the retaining device 100. In this way, torque can be applied to the second retaining element 101-2 by means of the auxiliary tool 300 to fasten it to or release it from the first retaining element 101-1.

[0058] Figure 6 Another view of the retaining device 100 with locking element 117 is shown. Ring 103 is locked by locking element 117. Locking element 117 is movably mounted on the first retaining element 101-1 and supported on the stop element 111 of the second retaining element 101-2. This prevents ring 103 from loosening. Ring 103 is only released when locking element 117 is pressed down.

[0059] Figure 7 The secondary locking mechanism of the retaining device 100 is shown. In cases where high torque is generated on the workpiece 200 due to machining forces in the milling machine, the secondary locking mechanism can prevent unlocking. The secondary lock includes a resilient locking element 117 that springs upward when the ring 103 is locked in the closed position.

[0060] A rod-shaped locking element 117 is rotatably mounted on the first retaining element 101-1 and, in the locked state, supports the stop element 111 of the second retaining element 101-2. The locking element 117 thus prevents the ring 103 from being released due to vibration during milling. When unlocked, the corresponding pin of the auxiliary tool 300 presses down on the locking element 117, thereby releasing it. In this position, the second retaining element 101-2 can rotate.

[0061] Figure 8 A block diagram of a method for holding a blank 200 is shown. In step S101, the blank 200 is inserted into a first holding element 101-1. In step S102, the blank 200 is clamped in the holding device 100 by the rotational movement of a second holding element 101-2, which is lockable to the first holding element 101-1. Thus, a stable fixation of the blank 200 between the two holding elements 101-1 and 101-2 is achieved.

[0062] Figure 9Another embodiment of the holding device 400 is shown. The holding device 400 further includes a first holding element 401-1 and a second holding element 401-2. The second holding element 401-2 is also used to clamp the blank 200 and can be locked to the first holding element 401-1 by rotational movement. The blank 200 is thus also clamped between the two holding elements 401-1 and 401-2.

[0063] Figure 10 A view of the second retaining element 401-2 of the retaining device 400 is shown. The second retaining element 401-2 is also formed of a ring 403. On the underside of the ring 403 are a plurality of rod-shaped arms 409 extending in the axial direction of the ring 403. The arms 409 extend from the ring 403 in a vertical direction. On the outer circumferential side of the ring 403, there are a plurality of notches 411, which create a gripping profile and facilitate rotation of the ring 403.

[0064] The pin-shaped guide portion 405 is located at the top of the arm 409 and extends radially inward toward the center of the ring 403. The guide portion 405 engages with the first retaining element 401-1, such that the two retaining elements 401-1 and 401-2 can be locked by rotational movement, and retaining tension can be applied to the workpiece.

[0065] Figure 11 A view of the first retaining element 401-1 of the retaining device 400 is shown. The first retaining element 401-1 includes a plurality of spring elements 407 for applying a clamping force to the guide portion 405 of the second retaining element 401-2. The spring elements 407 press the first and second retaining elements 401-1 and 401-2 against the blank 200. The spring elements 407 are formed by a V-shaped leaf spring disposed on the bottom surface of the first retaining element 401-1. One wing of the V-shaped leaf spring rests against the underside of the annular retaining element 401-1. When closed, the underside is away from the second retaining element 401-2. This wing can be attached to the annular retaining element 401-1 by a screw or bolt 417.

[0066] Another wing of the V-shaped leaf spring protrudes elastically along the axial direction and includes a groove 413 in which the guide portion 405 engages in the closed state. A plurality of radial recesses 415 are located on the outer circumferential side of the first retaining element 401-1, the number of which corresponds to the number of arms of the second retaining element 401-2. When the retaining elements 401-1 and 401-2 are assembled, the guide portion 405 of the second retaining element 401-2 is first guided axially through the recesses 415. Then, the retaining elements 401-1 and 401-2 rotate relative to each other. During this process, the guide portion 405 slides over the protruding wing of the leaf spring, which applies an increased compressive axial force to the second retaining element 401-2. In the stop position, the guide portion 405 engages the groove 413 and clamps the blank. Typically, the spring element 407 can also be formed by another elastic element that applies force axially to the retaining element 401-2, such as a coil spring or a pawl spring. In this way, the blank 200 can be clamped between the retaining elements 401-1 and 401-2.

[0067] All features explained and illustrated in connection with various embodiments of the invention can be provided in different combinations within the subject matter of the invention to achieve their beneficial effects simultaneously.

[0068] All method steps can be implemented by means suitable for executing the corresponding method steps. All functions performed by a feature can be process steps of a method.

[0069] The scope of protection of this invention is given by the claims and is not limited to the features explained in the specification or shown in the drawings.

[0070] List of reference numerals

[0071] 100 holding device

[0072] 101 Holding Element

[0073] 103 rings

[0074] 105 Guiding Section

[0075] 107 Spring Part

[0076] 109 bottom cut

[0077] 111 Stopping element

[0078] 113 Workpiece Socket

[0079] 115 ball thrust component

[0080] 117 Locking Component

[0081] 119 holes

[0082] 200 blanks

[0083] 201 Groove

[0084] 300 auxiliary tools

[0085] 301 controller

[0086] 303 sales

[0087] 400 holding device

[0088] 401 Holding Element

[0089] 403 rings

[0090] 405 Guiding Section

[0091] 407 Spring Element

[0092] 409 arms

[0093] 411 gap

[0094] 413 slot

Claims

1. A holding device (400) for a blank (200), having: - a first holding element (401-1) for inserting the blank (200); and - a second holding element (401-2) for clamping the blank (200), which can be locked to the first holding element (401-1) by a rotational movement, wherein the second holding element (401-2) comprises a guide portion (405) projecting radially inwards, the guide portion (405) is arranged on an arm (409) extending in the axial direction of the second holding element (401-2); the first holding element (401-1) comprises at least one spring element (407) for exerting a clamping force on the guide portion (405) of the second holding element (401-2).

2. The holding device (400) according to claim 1, wherein the second holding element (401-2) is formed by an open or closed ring (403).

3. The holding device (400) according to claim 1, wherein the spring element (407) is formed by a leaf spring.

4. The holding device (400) according to claim 1, wherein the first holding element (401-1) or the second holding element (401-2) comprises at least one recess (415) for the guide portion (405) to pass through.

5. The holding device (400) according to claim 1, wherein one side of a v-shaped leaf spring abuts the first holding element (401-1).

6. The holding device (400) according to claim 1, wherein the spring element (407) is arranged on a side of the first holding element (401-1) facing away from the second holding element (401-2).

7. An auxiliary tool (300) for opening the holding device (400) according to any one of claims 1 to 6, comprising at least one engagement element for engaging a hole or recess of the second holding element (401-2).

8. A method of holding a blank (200), comprising: inserting (S101) the blank (200) into a first holding element (401-1); and clamping (S102) the blank (200) by a rotational movement of a second holding element (401-2) which can be locked to the first holding element (401-1).

9. The method of claim 8, wherein, a clamping force is generated on the blank (200) in the direction of the first holding element (401-1).

10. The method of claim 8 or 9, wherein, a radially inwards projecting guide portion (405) of the second holding element (401-2) is supported on a spring element (407) of the first holding element (401-1).

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