DE102010013844A1 - Device for determining contour of curved eyeglass lens frame, has evaluation unit calculating contour of spectacle lens frame, and compensation element compensating gravitational force of pin carrier by applying force on contour - Google Patents

Abstract

The device has a pin carrier (21) with a stylus (24) that is movably mounted in a rotating version relative to a lens during mechanical scanning. A motor (12), transducer elements (30, 35) and potentiometers (31, 37) detect the relative motion between the pin carrier and/or the stylus, and another lens version. An evaluation unit (33) calculates contour of a spectacle lens frame from the signals output from the detecting units. A compensation element (22) compensates gravitational force of the pin carrier by applying force on the contour.

Description

The invention relates to a device for determining the contour of a curved spectacle frame by mechanical scanning, with a relative to the lens frame rotatable and along a vertical axis movably mounted pin carrier with a stylus disposed thereon, which rests with its radially outer end from the inside against the contour , with detection means for the relative movement between on the one hand pin carrier and / or stylus and on the other hand spectacle lens frame, and with an evaluation unit for calculating the contour of the spectacle frame from the output signals of the detection means.

Devices with these features are known, for example from the EP 1 974 854 A2 known. Common to such devices is the desire later, the spectacle lens receiving and provided with a socket groove inner contour of the spectacle frame as quickly as geometrically precise to exact geometrical data for the later peripheral processing of the respective lens, such as a CNC-guided spectacle lens edge processing machine To have available.

However, the scanning by means of the applied under a certain pressure against the socket groove stylus must not be done too fast, because then the stylus of the contour can no longer safely follow the contour in all cases, he rather lifts off the contour or he along the spectacle frame running socket groove leaves. This danger is based on the one hand on the always existing weight of the stylus, which tends to pull the stylus down. Above all, there is a danger in strongly curved, ie shell-shaped eyeglass frames and here especially if they are also designed significantly angular. The stylus can then very easily fall out of the socket groove in the area of the corners. An increase in the pressure force of the stylus against the socket groove is usually not really satisfactory solution. Because the increased pressure leads to a temporary deformation of the spectacle frame with the result that the determined geometry does not sufficiently reflect the actual geometry of the inner contour, so that it later Passungsproblemen when inserting the lens comes.

In view of the above problems has already been proposed to equip the stylus with a sequencing, which supports the tracking of the stylus when scanning the socket groove. In the EP 1 050 373 A2 a sequential control for the stylus is described, by means of which the radial movement of the stylus is regulated in dependence on the respective radius vector and in particular in dependence on the change of the radius vector. This is done by increasing the torque of the radial drive of the stylus as the radius vector increases and decreasing as the radius vector becomes shorter. However, the apparatus and control costs associated with this technical solution are high, without a significantly increased scanning reliability being achieved in the case of difficult spectacle frame forms.

The aim of the invention is therefore as smooth as possible the course of the socket groove and without the risk of falling out, which is also suitable for highly curved and / or narrow curve radii having spectacle lens frames. Furthermore, the aim is a small apparatus and control effort.

To solve this problem, the device for determining the contour of a curved spectacle frame with the features specified by a compensating element which acts on the pin carrier with a force directed against its weight force.

This device allows increased scanning safety by the scanning mechanism is supplemented by a compensating element, which exerts on the pin carrier an upward and therefore its gravitational force counteracting force. This reduces the risk that the sensing pin leaves the socket groove on its way along the socket groove due to its inertial forces. It is advantageous, however, already that the means according to the invention contribute to the fact that the pen always the complete, d. H. maintains bilateral contact with the two flanks of the socket groove. If this is not the case, inaccuracies of the geometric values detected with the device occur. Another advantage is that the pressure applied to the stylus to be scanned contour pressure force can be kept relatively low, since this force is no longer as before the crucial importance in the reliable leadership of the stylus.

Even with eyeglass lens holders with narrow radii, the stylus safely and accurately follows the socket groove, without leaving the web along the socket groove or slipping out completely due to the effect of the weight force and the mass inertia forces. This is true even for such critical peripheral regions of a spectacle lens frame in which this has a bending due to a strong curvature or shell shape with the result that the socket groove is not aligned horizontally in these peripheral regions, but with a significant inclination. Especially in these "bent" peripheral areas there is a risk that the stylus of the socket groove can not follow sufficiently.

By compensating or overcompensating for the weight of the pen support, including the stylus, the scanning process itself is little affected. Even with eyeglass lens holders, which are provided with narrow radii and / or have a strong curvature or shell shape, the stylus safely and accurately follows the socket groove, without it slipping out as a result of the effective weight and the inertia forces. This also applies to such peripheral regions of the spectacle lens frame, in which this shows a bending due to their strong curvature or shell shape, with the result that the socket groove is not aligned horizontally in these peripheral regions, but with a clear inclination. Especially in such peripheral areas there is usually the risk that the stylus is not sufficiently guided within the socket groove and he therefore leaves this.

Various embodiments of the device according to the invention are specified in the subclaims.

With an embodiment, it is proposed that the force exerted by the compensating element increases with increasing lifting of the pin carrier. This is based on the consideration that many spectacle frames for fashionable reasons, a strongly curved, d. H. show clearly shell-shaped design. With eyeglass frames designed in this way, there is the risk of insufficient guidance of the stylus on those obliquely arranged peripheral regions which are located far outside on the eyeglass frame, that is to say near the eyeglass temple appendix. It is advantageous if in these peripheral areas, the weight of pen support and stylus not only compensated, but possibly even overcompensated by the counterforce.

With a further embodiment, it is proposed that the compensating element is a lever which can be pivoted about a horizontal axis, the lever arm of which is formed in regions as a force transmission surface supported against the pin carrier. Preferably, the lever arm is supported from below against the pin carrier.

With a further embodiment, it is proposed that the force transmission surface of the lever arm is curved with the curvature outside facing upwards. As a result, it is achieved with simple apparatus that the force exerted by the compensating element increases with increasing lifting of the pin carrier.

With a further embodiment of the device is proposed that the lever extends beyond the horizontal axis out, and there is provided with a overcompensating the weight of the lever arm mass.

Alternatively, to generate the force counteracting the weight force, a spring can be used, which acts on the lever in such a way that the lever arm exerts an upward force.

As an alternative to the spring can be used as a force-generating means an electromagnet or an electric motor. Also, by an electromagnet or an electric motor, the lever can be applied in the sense that the lever arm exerts an upward force, and thus at least partially compensates the weight of the pin carrier and stylus.

The invention will be explained in more detail with reference to an embodiment shown in the drawing. On the drawing show:

1 in a plan view of the apparatus for determining the contour of a lens frame with a clamped in the device glasses frame;

2 in detail the engagement of a finger-like stylus in the groove on the inner contour of the lens frame;

3 a vertical section through the device and

4 in plan view engaging in the socket groove of the lens frame sensing stylus;

5 in a side view of a compensating element and the pin carrier with the stylus attached thereto;

6a the objects after 5 at a certain altitude of the pen carrier;

6b the objects after 5 at a different altitude of the pen carrier;

7a a section through the stylus and the lens frame with horizontally aligned socket groove and

7b a section through the stylus and the lens frame with significantly inclined aligned socket groove.

The device has a frame of an L-shaped profile piece 2 standing on supports 4 resting with her foot on a stationary surface 6 seated. On the horizontal leg of the profile piece 2 is the edge 7 a rotatable round plate 8th on, whose edge 9 on the vertical leg of the profile piece 2 is guided. The plate 8th is round and rotatable about its vertical center axis M. This is a motor 12 , its drive shaft 13 in suitable manner in a corresponding part of the plate 8th engages to rotate about the axis M.

The plate 8th has a diameter that is capable of one, here left, half 14a a spectacle frame 14 to wear. The spectacle lens frame 14 or their half to be scanned 14a is made by clamping and clamping elements 15 immovable on the top 8a the plate 8th positioned near its central axis M a long or oval hole 16 having.

Below the plate 8th is a sled 18 in the direction of the double arrow 17a ( 3 ) arranged movably. On the sledge 18 is the touch device 20 arranged. This consists of a vertical guide, in which a pin carrier 21 is moved up and down in the direction of the Z-axis. On the pencil carrier 21 presses from below into the 5 to 6b shown, pivoting on the carriage 18 stored compensation element 22 , Through the compensation element 22 becomes the net weight G of the pen carrier 21 and the attached stylus 24 compensated or overcompensated, which is explained below on the basis of 4 to 6b is described in more detail.

The designed in the manner of a column or double column pin carrier 21 sticking out through the hole 16 the plate 8th through to the later the spectacle lens receiving opening of the spectacle frame half 14a , Above the level 8a the plate 8th is located on the pin carrier 21 the substantially horizontally oriented stylus 24 , Its horizontal direction of movement corresponds to the direction of movement of the carriage 18 as indicated by the double arrow 17a is designated. The radially outer end of the stylus 24 has acute angles to each other extending side surfaces corresponding to the wedge-shaped groove cross-section of the socket groove 27 of the glasses frame. The extreme tip 26 of the stylus 24 slides on the groove bottom of the socket groove 27 along and is guided by the socket groove when the plate 8th with the help of the engine 12 is rotated about the axis M.

The vertically longitudinally movable pin carrier 21 is with the stylus 24 firmly and non-rotatably connected, further, the pin carrier 21 non-rotatable about its vertical axis. With the help of z. B. one against the carriage 18 supporting spring is on the pin carrier 21 and thus on the stylus 24 exerted a continuous horizontal force, whereby the stylus always under a certain pressure force F '( 5 . 7b ) against the groove 27 supported.

The pencil carrier 21 carries a vertically, ie working in the Z direction donor element 30 which is in a potentiometer 31 or immersed in an electromagnetic coil such that with the vertical movement of the pin carrier 21 one of the elevation of the pen carrier 21 corresponding measured value via the line 32 an evaluation and control unit 33 is supplied as Z-axis value.

At the the pen holder 21 carrying sled 18 is a horizontally operating donor element 35 provided in an electromagnetic coil or a potentiometer 37 slides. In this way, another control pulse is sent over the line 38 to the evaluation and control unit 33 guided, this control pulse of the horizontal position or movement of the stylus 24 equivalent. The evaluation and control unit 33 therefore receives from the travelers 30 . 31 and 35 . 37 Measurements related to the adjustment of the pen support 21 in a plane perpendicular to the goggle frame opening, and further in the horizontal direction perpendicular to this plane.

Furthermore, it is also the plate 8th rotating engine 12 as an angle encoder via the line 39 with the evaluation and control unit 33 connected so that from this not only the above data of the movement of the stylus 24 be recorded and stored in the axial and perpendicular direction, but also the values of the respective angular position of the stylus relative to the angular position of the lens frame 14 , For this purpose, the angle of the position of the plate 8th in the control unit 33 the data of the transducers 30 . 31 and 35 . 37 assigned so that every point of the socket groove 27 is determined by a total of three measured values. These can be reproduced in a CNC-controlled spectacle lens edge grinding machine directly or after storage, and control the processing steps of the grinding machine. The evaluation and control unit 33 So it is programmed to take from the data of the fair value transmitter 30 . 31 and 35 . 37 and the relative angular position calculates the three-dimensional contour of the curved spectacle frame.

It is also possible that the evaluation and control unit 33 control commands to the motor from the received signals 12 in the way that generates the rotational speed of the stylus 24 relative to the lens frame as a function of the radial velocity or radial acceleration and / or the velocity or acceleration in the Z-axis direction of the stylus 24 is changed relative to the eyeglass detection opening so that the radial velocity or the radial acceleration and / or the speed or acceleration in the direction of the Z-axis remains within predeterminable limits. In particular, the rotational speed of the stylus 24 controlled relative to the lens frame when the radial velocity and / or the velocity in the Z-axis direction of the stylus with increasing radius and / or Z-axis value increase, and is the rotational speed of the stylus 24 also regulated down relative to the lens frame when the radial velocity and / or the velocity in the direction of the Z-axis of the stylus 24 increase after a zero crossing and decreasing radius and / or Z axis value.

The higher the speed when the probe moves along 24 along the socket groove 27 is, the more difficult it is for the stylus, in view of the downward pulling weight and the mass-related moments of inertia of the contour still sufficiently follow, and the greater is accordingly the risk that the tip 26 the socket groove leaves. This danger is particularly pronounced in a strongly curved, ie shell-shaped spectacle frame, as they are in 4 in top view and in the 5 and 7b is shown in sectional views. Due to the strong shell shape, there is a pronounced bending of the spectacle frame, especially in those outer peripheral areas U1 and U2, which usually begin the eyeglass temple.

This fact is in the 7a and 7b shown in detail. The 7a shows a section through the stylus 24 and the lens frame with horizontal aligned and therefore largely unproblematic Fassungsnut 27 , on the other hand 7b the same cut with hanging, so clearly inclined aligned socket groove 27 , It can be seen how the lower, almost vertical flank 40 the total wedge-shaped framing groove 27 The downward-acting weight G is hardly able to resist. The stylus 24 is also different strong on the two flanks of the socket groove. Especially in such "bent" peripheral areas, therefore, the danger is greatest that during operation of the device of the stylus 24 the correct contact with the groove 27 loses.

As 5 shows become pin carriers 21 and stylus 24 by pivoting on the carriage 18 arranged compensation element 22 constantly applied with an upward force F, which is opposite to the weight G, whereby the weight G of the pen support including the stylus is compensated or overcompensated. Despite the narrow radii and the curvature of the spectacle frame follows the stylus 24 exactly at any time the socket groove and is not carried out by its own weight and by the also acting mass inertia forces or moments. This is especially true in the critical peripheral areas with pronounced bending, in which the socket groove 27 not horizontally, but aligned with a clear inclination, causing the stylus 24 only asymmetrical on the two flanks 40 the socket groove 27 is applied.

According to 5 is the compensation element 22 preferably designed as a two-armed lever, the manner of a rocker on the horizontal axis 22a is pivotally mounted. The top of the one lever arm 23 forms the force transmission surface 25 , It is supported from below against one on the pin carrier 21 freely rotatably mounted roller 28 from. At the other lever arm is a mass 29 whose lever arm and weight are dimensioned so that regardless of the pivoting angle of the compensating element 22 the lever arm 23 always a positive moment of force F on the pin carrier 21 and with it the stylus 24 exercises. The effective moment of the mass 29 can be adjustable. An adjustment of the force curve can also be achieved by the location of the axis 22a changeable and thus adjustable is designed.

The transmission area 25 is curved, with upwardly facing curvature outside. As the 6a and 6b show in comparison, can be by this configuration of the compensating element 22 to achieve a control curve that on the pin carrier 21 acting compensation force of the height position of the pin carrier 21 depends. For scanning the outer peripheral regions U1, U2 of a strongly curved spectacle lens frame as in FIGS 4 and 5 it has been shown to be advantageous if the force F increases from a low value F1 with the pin carrier lowered to a significantly higher value F2 with the pin carrier being raised at maximum. By selecting the curvature of the power transmission surface 25 You can set whether the increase is continuous, progressive or degressive.

Alternatively, a spring can be used to generate the force F, which lever 22 also acted upon in such a way that the lever arm 23 exerts an upward force. Alternatively, can be used as a force-generating means a mass, which via a once deflected rope with the pin carrier 21 connected is. Alternatively, can be used as a force-generating means an electromagnet or an electric motor.

LIST OF REFERENCE NUMBERS

2

profile piece

4

support

6

document

7

edge

8th

plate

12

engine

13

drive shaft

14

Lens frame

14a

Eyeglass frame half

15

Clamping and clamping elements

16

hole

18

carriage

19

guide

20

sensing device

21

pin carrier

22

Compensation element, lever

22a

axis

23

lever arm

24

feeler

25

Force transmission surface

26

prod

27

frame groove

28

role

29

Dimensions

30

transmitter element

31

potentiometer

32

management

33

Evaluation and control unit

35

transmitter element

37

potentiometer

38

management

39

management

40

flank

F

force

F '

pressure force

G

weight force

M

central axis

Z

vertical direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1974854 A2 [0002]
• EP 1050373 A2 [0004]

Claims (9)

Device for determining the contour of a curved spectacle frame by mechanical scanning, with a pin carrier rotatable relative to the spectacle frame and movably mounted along a vertical axis ( 21 ) with a stylus arranged thereon ( 24 ), which abuts with its radially outer end from the inside against the contour, with detection means ( 35 . 37 ; 30 . 31 ; 12 ) for the relative movement between on the one hand pin carrier and / or stylus and on the other hand spectacle lens frame, and with an evaluation unit ( 33 ) for calculating the contour of the spectacle lens frame ( 23 ) from the output signals of the detection means ( 35 . 37 ; 30 . 31 ; 12 ), characterized by a compensation element ( 22 ) which supports the pen carrier ( 21 ) is acted upon by a force (F) directed against its weight (G). Apparatus according to claim 1, characterized in that by the compensating element ( 22 ) applied force (F) with increasing lifting of the pin carrier ( 21 ) increases. Device according to claim 1 or 2, characterized in that the compensating element ( 22 ) about a horizontal axis ( 22a ) is pivotable lever whose lever arm ( 23 ) in some areas than against the pencil carrier ( 21 ) supported power transmission surface ( 25 ) is trained. Device according to claim 3, characterized in that the lever arm ( 23 ) from below against the pin carrier ( 21 ) is supported. Apparatus according to claim 3 or 4, characterized in that the force transmission surface ( 25 ) of the lever arm ( 23 ) is curved with upwardly directed curvature outside. Device according to one of claims 3-5, characterized in that the lever ( 22 ) over the horizontal axis ( 22a ), and there with a the weight of the lever arm ( 23 ) overcompensating mass ( 29 ) is provided. Device according to one of claims 3-5, characterized by a lever ( 22 ), the lever arm ( 23 ) upward pulling spring. Device according to one of claims 3-5, characterized by a lever ( 22 ), the lever arm ( 23 ) pulling upward electromagnet. Device according to one of claims 3-5, characterized by a lever ( 22 ), the lever arm ( 23 ) pulling upward electric motor.

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