Process and apparatus for the control of position of a tool of an edge-processing machine for glass panes

A process and apparatus for the control of the path of the grinding tool of an all-around edge grinding machine supporting a glass pane for movement about a rotational axis. The grinding tool is positively guided into contact with the edge of the glass pane as controlled by the contour of the glass pane. A scanning roller, also guided into contact with the edge of the glass panel provides the control heretofore described. Both the grinding head and scanning roller are movable in a direction toward the rotational axis of the glass pane. Path signals determined by the scanning roller are stored in a sliding register, and delayed at its output for a period of time required for movement of the glass pane through an angle which corresponds to the rotational angle (.alpha.,.beta.) between the point of contact of the scanning roller and the point of contact of the grinding tool on the edge of the glass pane. The path signals from the sliding register are used in position controlling the grinding tool. The scanning roller and the grinding tool each may be disposed on a sled for movement in directions colinear with a radius from the axis of rotation of the glass pane. The scanning roller and the grinding tool each may be disposed at the end of a rocker arm for movement along a circular path.

DESCRIPTION 
1. Technical Field 
The invention relates to a process for the control of a position taken by a 
grinding tool in processing (grinding) the edges of a glass pane and 
pressure exerted by the grinding tool during the process. The control and 
movement of the grinding tool are functions of the contour of the glass 
pane undergoing the process. The invention, also, relates to the apparatus 
for carrying out the process. 
2. Background of the Invention 
German Offenlegungsschrift No. 1928 162 discloses an edge grinding machine 
of the type of the invention. According to the publication, positive 
guidance of a grinding unit is provided by a template whose size and shape 
correspond to the size and shape of the glass pane to be edge ground. The 
publication, further, discloses that the template is placed parallel to 
the glass pane, and a guide roller which controls the edge grinding 
machine follows along the contour of the template. 
Quite obviously the apparatus of the publication may be used in the 
positive guidance of the grinding unit when glass panes of the same shape 
and size are moved seriatim to the edge grinding machine to be processed. 
If, however, there should be a change in either the shape of the glass 
pane or the size of the glass pane, or both, from one glass pane to the 
next, either the template must be exchanged for a proper template or the 
program which shall determine the path of the grinding unit must be 
exchanged for another program. Furthermore, in the case of the known 
apparatus, such as that of the publication, a prerequisite of proper 
operation in grinding is that of precise positioning of the glass pane 
relative to the template or to a reference mark of the apparatus as 
determined by the control. These measures represent a considerable 
disadvantage of the prior art and a limitation of the apparatus. 
SUMMARY OF THE INVENTION 
The invention is directed to a process for the control of the position and 
path of a grinding tool of an all-around edge processing apparatus for 
glass panes. Particularly, the process is one which may be carried out 
without the requirement heretofore of a template. According to the 
process, the apparatus may be used in edge processing of glass panes of 
the most varied shapes without any special measures being necessary 
insofar as a requirement of change of the program of the path, or a 
precise positioning of the glass pane relative to some reference mark of 
the apparatus in the processing station. 
The process may be characterized by the use of an element in concert with 
the grinding tool and the processing of signals generated by the element 
in scanning the edge of the glass pane. More particularly, the element is 
disposed for movement in the direction toward the rotational axis of a 
plate, supporting the glass pane for movement, and displaced by an angle 
(.alpha.,.beta.) in relation to the grinding tool. The path control 
program for the grinding tool will be determined by values as may have 
been stored in a sliding register and, then, found at the output of the 
sliding register after a timed interval corresponding to the rotational 
angle (.alpha.,.beta.) between the point of contact of the element and the 
point of contact of the grinding tool along the edge of the glass pane. 
The output value is used to control the position of the grinding tool 
relative to the axis of rotation of the glass pane. 
Contrary to the prior art, represented by the publication, the process of 
the invention is in the positioning of the grinding tool for each 
individual glass pane by a determination, individually, by scanning the 
contour of the edge of the glass pane that is to be processed. Information 
from the scanning process, at least for a partial extent of the periphery 
of the edge of the glass pane, relating to path or position, is fed to a 
storage from which it is taken after a period of time corresponding to the 
time taken for rotation of the glass pane through the rotational angle of 
displacement of the element for scanning and the grinding tool. To this 
end, the storage will contain, temporarily, a control signal corresponding 
to the length of the extent of that periphery. 
According to the invention, not only is it possible to process glass panes 
having substantially any shape without resort to special measures for 
aligning the glass panes, for example, it is also possible to process 
glass panes of different shape as they are moved seriatim to the 
all-around edge processing apparatus. Thus, the application of the 
grinding machine may be increased considerably. Further, the process may 
be conducted more economically since readjusting times in the readjustment 
from one program of path control to another are omitted. 
While the process has been generally described in relation to the practice 
of the process in the control of tools of an all-around edge grinding 
apparatus, the process may be used in the same manner in the control of 
tools in other apparatus by which glass panes may be processed either 
along their edge or on a surface parallel to the edge of the glass pane. 
With regard to the latter capability, it oftentimes is the case that a 
glass pane is provided along the edges of the glass pane or along the edge 
area of the surface of the glass pane with a strip which may be an 
electrically conductive strip or a decorating strip. The path control 
process according to the invention may be utilized in this operation, 
also. A further capability of the process may be that of incorporation of 
a control in a program of measurement of the contour of the glass pane. In 
this manner, for example, the invention may be used for control of the 
shape of the glass pane by comparing the values determined by the control 
arrangement with stored theoretical values. 
Many alternatives may be resorted to in the overall construction of the 
apparatus for carrying out the process. For example, according to a first 
form of the invention the grinding tool and a scanning element may be 
disposed for movement linearly along an axis that is colinear with a 
radius from the rotational axis of the plate which mounts the glass pane 
for movement. The grinding tool and the scanning element are displaced by 
an angle .alpha. described by the radii as discussed. The grinding tool 
and the scanning element are disposed on a sled, each of which is movable 
relative to an electric path recorder. The grinding tool may be provided 
with an adjustment motor drive and the control may include a sliding 
register storage and a regulating amplifier controlled by the path 
recorder which shall cooperate with the sled carrying the scanning 
element. A control signal from the sliding register storage, delayed for a 
period of time corresponding to the period of time required for rotation 
of the plate through the angle .alpha., controls the position of the 
grinding tool. 
According to another form of the invention, the grinding tool is disposed 
on a first rocker arm, and the scanning element is disposed on a second 
rocker arm. Both the grinding tool and the scanning element are capable of 
movement in a circular path about the axis of rotation of each rocker arm, 
and the rocker arms, in relation to the rotational axis of the plate, are 
displaced by an angle .beta.. The first rocker arm is provided with a 
collating rotor which provides a signal determination of the angular 
position of that rocker arm. The control for controlling the position of 
the grinding tool comprises an angle producer, a sliding register storage 
for temporarily delaying a control signal to the collating motor of the 
first rocker arm carrying the grinding tool and a regulating amplifier 
which shall directly control the second rocker arm with the control signal 
after the delay. The delay corresponds to the time taken for rotation of 
the glass pane through the rotational angle .beta.. 
A torque motor acts upon the scanning element so that the scanning element 
scans the edge of the glass pane under conditions of constant pressure. In 
the first form of the invention, the torque motor acts upon a sled which 
mounts the scanning element for linear movement, and in the second form of 
the invention, the torque motor acts about the rotational axis of the 
rocker arm which mounts the scanning element. The torque motor, also, 
provides for the movement of the scanning element between its operating 
and rests positions. 
The grinding tool effectively should be pressed against the edge of the 
glass pane under conditions of a continuous or regulating force. In 
certain cases, preferably during rotation of the glass pane and movement 
of the scanning element as it scans a sharply acute corner, the torque 
motor may assist in changing or correcting the force of pressure of the 
grinding tool. The change or correction of the grinding tool may be 
programmed, also. 
A speedometer machine may be mechanically connected with the drive shaft of 
a motor for adjusting the position of the scanning tool. The speedometer 
machine develops a signal which together with signals from a path 
recorder, processed by an evaluation unit, provide a start signal. The 
start signal functions to regulate the speed of the drive to the plate and 
the glass pane which it supports. Thus, the start signal represents a 
measurement of the speed of a position change, for example, whenever a 
sharply acute corner of the glass pane moves past the scanning element and 
grinding tool. 
The discussion above which briefly develops the features and advantages of 
the invention in both the process and apparatus which distinguish it from 
the prior art will be greatly expanded upon as the description continues, 
and as the description is considered with the drawing.

BEST MODE FOR CARRYING OUT THE INVENTION 
With reference to FIG. 1, there is illustrated a glass pane 1 which is to 
be ground along its edges, completely around the perimeter of the glass 
pane. The glass pane may take any form, such as that of the three-sided 
glass pane of the Figure. A plate 2 provides a support for the glass pane. 
The plate may be of the type having capability of developing a suction 
force within the confines of a rim, and the plate mechanically supports 
the glass pane within the region of its center of gravity for movement 
about an axis of rotation. To this end, a motor 3 is connected to the 
plate and drives the plate rotationally at a slow, constant speed during 
the grinding process. A drive shaft 24 illustrated by the dotted lines in 
FIG. 1 serves to drivingly connect the plate and motor. 
A sled 7 is mounted for movement relative to the axis of rotation of plate 
2 and glass pane 1. Particularly, and with regard to FIG. 2, it will be 
noted that the sled is mounted on a pair of rails 8 supported in spaced, 
parallel relation below the plane of the glass pane. The rails are mounted 
in a fixed orientation (by frame structure, not shown) relative to the 
glass pane and the sled 7 is adapted for movement back and forth, along 
the rails longitudinally in a direction radially inward and outward of the 
axis of rotation. A grinding tool 6 is carried by the sled for movement 
with the sled. The grinding tool is mounted for rotation, for example, in 
the counterclockwise direction in FIG. 1, by structure to be described. 
A second sled 12 is also mounted relative to the axis of rotation of plate 
2 and glass pane 1. The manner of mounting sled 12 may duplicate the 
manner of mounting of sled 7 whereby sled 12 may move back and forth, 
along a similar path. A scanning roller 11 is carried by sled 12. 
Sled 12 and sled 7, more particularly the axes of their longitudinal 
movement path relative to the axis of rotation of plate 2 are displaced by 
an angle .alpha. in the direction opposite to the direction of rotation of 
the glass pane (see the arrow in FIG. 1). 
A spindle 14 supports sled 12. A motor 16 is mechanically coupled to the 
spindle. A driving input to the motor drives the spindle in one direction 
or the other. Drive of the motor is followed by rotation of spindle 14, 
thereby to drive sled 12 in the manner heretofore discussed. At the 
commencement of a grinding process, the sled 12 and scanning roller 11 
will be located to the position illustrated in FIG. 1 and at the end of 
the grinding process the sled and scanning roller will be located to a 
position of rest radially removed from the operative position. 
The motor 16 may be a torque motor and functions in a manner so that the 
scanning roller 11, during a grinding process, is always pressed against 
the edge of glass pane 1. The torque motor, further, maintains a constant 
pressure between the scanning roller and the glass pane. A speedometer 
machine 13 is coupled either with spindle 14 or motor 16 and measures the 
speed of change of position of the scanning roller relative to the glass 
pane. The speedometer machine will be described in greater detail as the 
description continues. For the moment, however, it is to be noted that the 
speedometer machine provides a signal output in response to the 
measurement of change of position which output is used in regulating the 
contact pressure developed between grinding tool 6 and the edge of glass 
pane 1 to be ground. The signal output is also fed to a measuring trigger 
95, see FIGS. 1 and 3. 
A motor 15 provides a driving input to scanning roller 11 to rotate the 
scanning roller for purposes of substantial reduction of friction losses. 
The mechanical coupling of the motor and the scanning roller is 
illustrated by the dash line in FIG. 1. 
A path recorder 18 provides a signal output representative of the position 
of sled 12 and consequently the scanning roller 11 relative to the axis of 
rotation of plate 2. The path recorder is in the form of an electrically 
conductive finger biased into contact with a sliding resistance 19. The 
sliding resistance is connected at one end in series with an 
analog/digital converter 21. Movement of the finger or tap along the 
sliding resistance in response to the positioning of sled 12 serves to tap 
a voltage at a level which represents a linear position of orientation of 
the sled relative to the axis of rotation of plate 2. The voltage level 
which also represents the position of the scanning roller in relation to 
the same reference is connected to the analog/digital converter. The 
connection is a series connection along line 20. The output of the 
analog/digital converter is a digital value representing the voltage at 
the tap. The output is connected to a sliding register 22. 
The sliding register 22 may comprise a component of a microcomputer. A 
timing pulse generator 23 is connected to the sliding register and times 
the sliding register in accordance with the speed of rotation of plate 2. 
To this end, the timing pulse generator is coupled mechanically to drive 
shaft 24, and electrically coupled to the sliding register 22. 
A digital/analog converter 25 is connected at the output of the timing 
pulse generator 23. In a manner to be discussed, the output signal of the 
digital/analog converter, in the form of a timed voltage level, is used to 
provide position control of the grinding tool 6. 
Sliding register 22 is of a construction such that the output signal 
comprising a theoretical value voltage for position control of the 
grinding tool 6 is delayed by a time interval equal to the length of time 
required for rotation of plate 2 through the angle .alpha.. As indicated, 
the plate 2 is rotated at a constant speed and the angle of rotation which 
is of concern is enclosed by the dot-dash radial lines (see FIG. 2) 
extending colinearly with the axes of movement of sleds 7, 12. When the 
plate shall have rotated through the angle .alpha., the grinding tool 6 
will be located at the position along the edge of the glass pane relative 
to the axis of rotation of plate 2, to which the scanning roller 
previously was located. 
A spindle 29 supports sled 7. A motor 28 is mechanically coupled to the 
spindle to rotate the spindle in one direction or the other thereby to 
adjust the position of the sled, and consequently the grinding tool 6, 
relative to the axis of rotation of plate 2. The motor may be an adjusting 
motor, triggered into operation by the timed voltage output of 
digital/analog converter 25, as regulated by regulating amplifier 31. The 
connection is by line 30. 
A path recorder 34 like the path recorder 18 provides an electrical voltage 
representative of the position of sled 7 and consequently the grinding 
roller relative to the axis of rotation of plate 2. The path recorder 
provides a tap movable along a sliding resistance 35 in the form of a 
grinding contact. The electric voltage which is tapped, comprising an 
actual value serving as an acknowledgement of the grinding tool position 
is connected to the regulating amplifier 31. The connection of path 
recorder 34 to regulating amplifier 31 is completed by line 36. 
The path recorder 34 provides a second function. To this end, and in 
concert with operation of a speedometer machine 38, the path recorder 
controls the speed of drive (revolutions per minute) of plate 2 as may be 
required if there is a recognized change in the position of sled 7 
relative to the axis of rotation of plate 2. In this manner, and as 
discussed below, the effective grinding speed may be maintained constant. 
If there should be a change in the position of the grinding tool 6 toward 
the edge of the glass pane 1, or in the opposite direction, there will 
result an undesirable increase or decrease of the grinding effect. 
Accordingly, it is necessary to compensate for these undesirable 
influences. To this end, it is possible to change the speed of rotation of 
plate 2 as a factor of the position of sled 7, and consequently the 
grinding tool, as well as the rate of change of the position of the sled 
relative to the axis of rotation of the plate. Particularly, a series of 
voltages generated by the path recorder 34 and speedometer machine 38, the 
latter of which is coupled either with the spindle 29 or motor 28, are 
connected to an electronic unit 39. The voltages include the voltage 
output of path control 34, also connected with the regulating amplifier 
31, and the voltages U.sub.t and U.sub.w generated by speedometer machine 
38. The electronic unit processes the several inputs to provide a starting 
voltage U.sub.s. This voltage which is a theoretical value voltage 
provides an input to the regulating amplifier 40. A speedometer machine 42 
is mechanically coupled to drive shaft 24. The speedometer machine 
provides a starting voltage which is an actual value representing the 
speed of the drive shaft. The actual voltage is connected on line 43 to 
the regulating amplifier 40. The output of regulating amplifier 40 is 
connected over line 41 and provides a control for motor 3, and, thus, the 
speed of rotation of plate 2. 
Referring now to FIG. 2, a torque motor 45 may be provided either for 
maintaining a specific grinding force between the grinding tool 6 and the 
edge of glass pane 1 which is to be ground or regulating the grinding 
force in accordance with a predetermined program. The torque motor may be 
mechanically coupled between the adjusting motor 28 and sled 7. A 
potentiometer 46 is provided in the system for adjustment of the desired 
theoretical value for maintaining the specific grinding force. 
A pair of pressure components comprising load cells 47, 48 measure the 
grinding pressure exerted between the grinding tool 6 and the drive motor 
for the grinding disc. The load cells are mounted on a plate 49. The 
plate, in turn, is connected mechanically to sled 7 by the load cells 47, 
48. The power component measured by load cell 47 results from the 
pertinent spatial position of the edge of the glass pane relative to the 
grinding disc. This power component may be a positive or a negative value 
and may change constantly as the spatial position of the component 
changes. The effective grinding pressure to be exerted on the edge of the 
glass pane will correspond to the geometrical sum of two power components. 
The values from each of the load cells 47, 48 converted by the load cells 
themselves into electrical voltage values, are connected to computer 50. 
The values comprising the value U.sub.1 representing the power component 
from load cell 47 and the value U.sub.2, representing the power component 
from load cell 48, are geometrically summed by the computer, and a voltage 
U.sub.a (actual value) at the output of the computer provides a regulating 
voltage for regulating the torque motor 45. The voltage U.sub.a is an 
actual value of the automatic control system and together with a 
theoretical value voltage, adjusted by potentiometer 46, provides the 
input to a regulating amplifier 51. The output of regulating amplifier 51 
triggers the torque motor 45. 
Regulation of the grinding pressure may also be carried out by following a 
program which functions to lower the grinding force exerted by the 
grinding disc of the grinding tool at each corner of glass pane 1, and to 
increase the grinding force once the region of the corner has been 
processed following rotation of the glass pane relative to the grinding 
tool. Generally, this operation requires several potentiometers in place 
of the potentiometer 46, with the potentiometers being switched into and 
out of a circuit to a control voltage in some succession of operation 
corresponding to the program. A system of an all-around grinding program 
for regulating the grinding pressure may be seen in FIG. 3. 
The system for control of an all-around grinding program of FIG. 3 is a 
system capable of use with a multi-edged glass pane. Particularly, the 
system comprises a counter 90 of preselection-digital type, illustrated as 
enclosed within the dash line. Any commercial counter having ten 
capabilities of preselection may be used. The counter will have a function 
capability to change the grinding pressure at a maximum of five corners 
and, then, to set the standard pressure once the corner has rotated 
relative to the grinding tool. The change in grinding pressure will be 
that of a decrease at a corner and an increase to that of the standard 
pressure. 
Potentiometer R1 functions to adjust a preselected theoretical value of 
pressure, while the value of guiding pressure, through some decrease for 
individual corners, is adjusted by adjustment of potentiometers R2-R6. 
Thus, potentiometer R2 may be adjusted to adjust the grinding pressure at 
a first corner, while the successive potentiometers adjust the grinding 
pressure at the next and following corners. 
A control voltage may be sensed on line 91 and connected through contact P1 
to the regulating amplifier 51. Potentiometer R7 serves the purpose of 
raising the grinding pressure at the completion of the grinding process 
and to pull back the grinding tool to the position at which the grinding 
process may commence. The control voltage, adjusted by adjustment of 
potentiometer R7, is connected through contact P2 to the regulating 
amplifier, also. 
Speedometer machine 13 provides a control signal for changing, that is, 
decreasing the grinding pressure at each of the several corners of the 
glass pane. Whenever the scanning roller 11 scans a corner of the glass 
pane, the scanning action is expressed in a voltage value and a change in 
polarity of the voltage. The signal representing the change in voltage 
value and that of the reversal of polarity of the voltage provides a 
control signal for triggering the counter 90. 
The grinding pressure normally will require change when sensing an acute 
angled corner as the corner moves relative to the grinding tool. The 
signal from speedometer machine 13 is connected to a measuring trigger 95. 
A potentiometer 96 may be adjusted to control or fix the desired switching 
point, representing the first corner having the acute character requiring 
a change of the grinding pressure. Thereafter, speedometer machine 38 will 
signal a corner. Measuring trigger 95 will respond to the corner signal 
and the relay d1 will energize to close the relay switch d1 and a ganged 
relay switch d2 thereby to energize relay d2. Relay d2 is a holding relay 
and connects the counter 90, then at a zero level, with the timing pulse 
generator 23. It will be recalled that the timing pulse generator is 
mechanically coupled to drive shaft 24. As illustrated in FIG. 1, the 
timing pulse generator is connected to the sliding register to provide 
timing in accordance with the speed of rotation of the drive shaft. The 
counter 90 is programmed in a manner that after a turn of the glass pane 1 
through the angle .alpha., meter relay Z1 will respond. Whereas, 
heretofore, potentiometer R1 functioned to adjust the standard pressure or 
preset the theoretical value, a response of meter relay Z1 will switch 
potentiometer R2 into the circuit and switch potentiometer R1 out of the 
circuit. Thus, potentiometer R2 will be used to preset the theoretical 
value. The potentiometer R2 will remain on as a result of that 
preselection and will remain for a period determined by the rotary angle 
of plate 2. When meter relay Z2 shall be triggered the potentiometer R1, 
again, will be connected to the control voltage and the circuit to 
potentiometer R2 will open. At the instant of triggering the meter relay 
Z2 the circuit to circuit breaker wiper d3 will open. As a result of the 
open circuit, relay switch d3 opens to deenergize relay d2. The counter 
timing, then, is interrupted and the counter 90 is stopped. This condition 
remains until the speedometer machine 13 responds to the second corner 
having the acute character which shall require a change in the grinding 
pressure. 
When there shall be a response from speedometer machine 13, the relay d1 is 
energized to again energize relay d2 and the process which has been 
described is repeated. The process is repeated, however, through operation 
of meter or preselection relays Z3 and Z4. These preselection relays and 
their operation result in the simultaneous switching of potentiometers R1 
and R3 into and out of the control voltage circuit. In this manner one 
potentiometer or the other will be operative in a control sense. When 
potentiometer R3 is switched out of the circuit the circuit to relay d3 
opens. The process is repeated through response of speedometer machine 13 
to the remaining corners having the critical acute character. In these 
responses the preselection relays Z5 and Z6, . . . Z9 and Z10, if there 
shall be five corners, will operate. 
A glass pane having a number of corners, up to five corners with each 
corner having an acute characteristic requiring a change in grinding 
pressure, may be ground following the described process. And, each corner 
may be ground by application of a different grinding pressure by 
adjustment of the potentiometers R2-R6. At the completion of the 
all-around grinding process, an eraser entry over line 98 sets the counter 
90 to zero. 
The operation is as follows: a scanning roller 11 and grinding tool 6 
together with their supporting sleds 12 and 7, respectively, are located 
to a retracted, rest position. A glass pane 1, either automatically or 
manually, is positioned on plate 2 and the plate is connected to a source 
of vacuum for purposes of securement of the glass pane for rotation. When 
the glass pane is secured it is driven in rotation, the speed of which is 
determined by a motor 3 under control of a path recorder 34 according to 
the positional relationship of the grinding tool 6 in the rest position. 
The current for motor 16 is switched on thereby to locate the sled 
adjacent the glass pane and in a position that the scanning roller rests 
against the edge of the glass pane. The motor 16 functions as a torque 
motor to adjust the pressure of the scanning roller against the edge of 
the glass pane. At this point, that is, when the scanning roller is in the 
scanning position, the electronic system commences the grinding operation. 
The sled 7 and sled 12 are displaced in a phase-shifted manner through a 
rotary angle .alpha.. The regulating arrangement including the manner of 
regulation of grinding pressure is as illustrated in FIG. 3 and discussed 
above. 
A second form of the apparatus of the invention may be seen in FIG. 4. This 
form differs from the form illustrated schematically in FIG. 1 principally 
in the manner of mounting the grinding tool and the scanning roller. 
Whereas, referring to the FIG. 1 form, the grinding tool 6 was mounted on 
sled 7 and scanning roller 11 was mounted on sled 12, with both of the 
sleds being movable linearly along a longitudinal axis arranged colinearly 
with a radius extending from of the axis rotation of plate 2, in the form 
of the invention now to be described the grinding tool and scanning roller 
are mounted on respective rocker arms. 
Referring to FIG. 4, a glass pane 1 is mounted on plate 2 for movement 
about the rotational axis of the plate. The positional relationship of the 
glass pane and the construction of the plate are as discussed, above. A 
driving motor 53 is connected to the rotational axis by drive shaft 73 to 
drive the plate at a constant speed. As indicated, a grinding tool 56 and 
scanning roller 65 are mounted by rocker arms 57 and 63, respectively. 
Turning to the grinding tool 56, the grinding tool or disc is disposed at 
one end of rocker arm 57. The other end of the rocker arm is mounted on an 
axis 58 so that the grinding tool may be moved or guided in a circular 
path about the axis 58. A motor 59 comprises a collating or adjusting 
motor. The motor is mechanically coupled to the axis 58 and a drive to the 
motor determines the angular position .epsilon. of the rocker arm 57 
relative to a reference line connecting the axis 58, the axis of rotation 
of plate 2 and an axis 64, the latter of which defines the center of a 
circular path within which the scanning roller 65 may be moved. The 
adjusting motor will also determine the angular position of the grinding 
tool or disc which moves with the rocker arm 57. 
A torque motor 60 is located concentrically about the axis 58. The torque 
motor may function in response and according to a program, and provides 
regulation of the grinding pressure exerted by the grinding tool or disc 
on the edge of glass pane 1. The regulating function of torque motor 60 is 
independent of the angular position of rocker arm 57 so that the grinding 
pressure remains constant as the glass pane rotates. Regulation of the 
grinding pressure may also follow the manner of control illustrated in 
FIG. 3. 
The rocker arm 63 mounts the scanning roller in similar fashion and is 
similarly mounted to guide or move the scanning roller in a circular path 
about the axis 64. The axis 64 is displaced from the axis 58 by an angle 
.beta. in the direction of rotation of plate 2. The disposition of axis 64 
as illustrated in FIG. 3, located along the reference line, is displaced 
at an angle of 180.degree.. 
The rocker arms 57 and 63 are coextensive in length. A motor 66 is 
mechanically connected to the scanning roller for driving the scanning 
roller to reduce or substantially eliminate any friction loses as the 
scanning roller tracks the edge of the glass pane. A torque motor 67 is 
arranged coaxially along axis 64 to assure that the scanning roller exerts 
a constant force on the edge of the glass pane. The torque motor, also, 
functions to return rocker arm 63 to a rest position after the scanning 
process or prior to the commencement a grinding process. At this time the 
glass pane 1 will have been disposed on plate 2 and secured by a vacuum 
force, and the scanning roller 65 will have been moved to the edge of the 
glass pane. 
An angle generator 68 which is mechanically coupled to the axis 64 
determines the angle or swivel angle .gamma. of rocker arm 63 and scanning 
roller 65 relative to the aforementioned reference line. The angle 
generator functions to deliver a DC voltage signal corresponding to the 
angle .gamma.. The signal is converted by an analog/digital converter 71 
to a corresponding digital value, and the digitized signal is connected to 
a sliding register 72. A timer 74 mechanically coupled to drive shaft 73 
for driving plate 2 times the sliding register. Particularly, the timer is 
designed in a manner that the digitized signal connected to the sliding 
register appears at the output of the sliding register when the plate 2 
and the rotary value of movement indicates rotation through the angle 
.beta.. In the form of FIG. 4, the rotation will be through an angle of 
180.degree.. 
The sliding register 72 may comprise a part of a microcomputer and the 
signal output, delayed by the timer 74, provides an input to the 
digital/analog converter 75. The analog voltage value at one input of 
regulating amplifier 76, therefore, is a theoretical value voltage used to 
control or adjust the adjusting motor 59. The control is over line 77. An 
angle generator 82 mechanically coupled to the axis 58 of rocker arm 57 
develops an actual value of the angular position .epsilon. of the rocker 
arm 57. The actual value signal of the angle generator provides a second 
input to the regulating amplifier 76. This control is over line 79. 
To compensate for any influence exerted by the spatial position of the 
processed part of the edge of the glass pane, at any time, on the 
effective grinding speed, it is necessary to control the speed of rotation 
of drive shaft 73 and plate 2. To this end, it is necessary to regulate 
motor 53, which regulation will be a function of the angular position of 
rocker arm 57 and the speed at which the rocker arm may swivel about the 
axis 58. 
In the regulation of motor 53, a voltage U.sub.w which is the output of 
angle generator 82 and a voltage U.sub.t which is the output of the 
speedometer machine 80, both of which are mechanically coupled to the axis 
58 of the rocker arm 57, are processed by an electronic unit 84 which 
provides a starting voltage U.sub.s. The starting voltage is a theoretical 
value voltage representing the speed of the motor 53 which provides an 
input to regulating amplifier 85. An actual value voltage representing an 
actual speed of rotation sensed by speedometer machine 78 is connected to 
another input of the regulating amplifier. The output of the regulating 
amplifier, in turn, is connected to motor 53. 
The form of the invention of FIG. 4 permits regulation of the effective 
grinding pressure. The regulation control is a function of the value of 
the spatial position of the edge of the glass pane to a constant value or 
to a predetermined programmed value. To this end, a potentiometer 81 is 
adjusted to the theoretical value of the grinding pressure, or the 
regulation control may follow the scheme discussed in relation to FIG. 3, 
to provide an input to a regulating amplifier 87. The regulating amplifier 
provides control for the torque motor 60. Further, the grinding tool 56 
may be mounted by a pair of load cells 88, 89 to the rocker arm. In a 
manner as heretofore discussed, the load cells are connected to a computer 
92. The input U.sub.1 and U.sub.2 from the respective load cells 
representing the power components of the effective grinding pressure as 
positive or negative electric voltages are geometrically summed by the 
computer. The output comprises an actual value of the regulating circuit 
and is the input at the other input terminal of the amplifier.